Integrate local changes

17 files changed, 2863 insertions, 843 deletions

diff --git a/gnu/usr.bin/cvs/configure b/gnu/usr.bin/cvs/configure
index f2c3eabbcc8..dd3ce3fc14d 100644
--- a/gnu/usr.bin/cvs/configure
+++ b/gnu/usr.bin/cvs/configure
@@ -1856,7 +1856,7 @@ EOF
 
 fi
 
-for ac_func in mkdir rename strstr dup2 strerror valloc waitpid vasprintf strtoul
+for ac_func in mkdir rename strstr dup2 strerror valloc waitpid memmove vasprintf strtoul
 do
 echo $ac_n "checking for $ac_func""... $ac_c" 1>&6
 echo "configure:1863: checking for $ac_func" >&5
@@ -3481,20 +3481,25 @@ EOF
 fi
 fi # enable_server
 
+cat >> confdefs.h <<\EOF
+#define PRESERVE_PERMISSIONS_SUPPORT 1
+EOF
+
+
 echo $ac_n "checking for cygwin32""... $ac_c" 1>&6
-echo "configure:3486: checking for cygwin32" >&5
+echo "configure:3491: checking for cygwin32" >&5
 if eval "test \"`echo '$''{'ccvs_cv_sys_cygwin32'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
   cat > conftest.$ac_ext <<EOF
-#line 3491 "configure"
+#line 3496 "configure"
 #include "confdefs.h"
 
 int main() {
 return __CYGWIN32__;
 ; return 0; }
 EOF
-if { (eval echo configure:3498: \"$ac_compile\") 1>&5; (eval $ac_compile) 2>&5; }; then
+if { (eval echo configure:3503: \"$ac_compile\") 1>&5; (eval $ac_compile) 2>&5; }; then
   rm -rf conftest*
   ccvs_cv_sys_cygwin32=yes
 else
diff --git a/gnu/usr.bin/cvs/configure.in b/gnu/usr.bin/cvs/configure.in
index 2296f71af59..cc678db8985 100644
--- a/gnu/usr.bin/cvs/configure.in
+++ b/gnu/usr.bin/cvs/configure.in
@@ -63,7 +63,7 @@ AC_TYPE_MODE_T
 AC_TYPE_SIZE_T
 AC_TYPE_PID_T
 AC_STRUCT_ST_BLKSIZE
-AC_REPLACE_FUNCS(mkdir rename strstr dup2 strerror valloc waitpid vasprintf strtoul)
+AC_REPLACE_FUNCS(mkdir rename strstr dup2 strerror valloc waitpid memmove vasprintf strtoul)
 AC_CHECK_FUNCS(fchmod fsync ftime mktemp putenv vprintf ftruncate timezone getpagesize initgroups fchdir sigaction sigprocmask sigvec sigsetmask sigblock tempnam tzset readlink wait3)
 
 dnl
@@ -348,6 +348,12 @@ if test "$ac_cv_func_crypt" = yes; then
 fi
 fi # enable_server
 
+dnl For the moment we will assume that all systems which have
+dnl the unixyness to run configure are unixy enough to do the
+dnl PreservePermissions stuff.  I have this sinking feeling that
+dnl things won't be that simple, before long.
+AC_DEFINE(PRESERVE_PERMISSIONS_SUPPORT)
+
 dnl On cygwin32, we configure like a Unix system, but we use the
 dnl Windows support code in lib/fncase.c to handle the case
 dnl insensitive file system.  We also need some support libraries.  We
diff --git a/gnu/usr.bin/cvs/contrib/Makefile.in b/gnu/usr.bin/cvs/contrib/Makefile.in
index 8bd2408a90d..462ae89f65e 100644
--- a/gnu/usr.bin/cvs/contrib/Makefile.in
+++ b/gnu/usr.bin/cvs/contrib/Makefile.in
@@ -106,7 +106,7 @@ ls:
 .PHONY: ls
 
 clean:
-	/bin/rm -f *.o core
+	rm -f *.o core
 .PHONY: clean
 
 distclean: clean
diff --git a/gnu/usr.bin/cvs/lib/memmove.c b/gnu/usr.bin/cvs/lib/memmove.c
new file mode 100644
index 00000000000..8818d46544c
--- /dev/null
+++ b/gnu/usr.bin/cvs/lib/memmove.c
@@ -0,0 +1,57 @@
+/* memmove -- copy memory regions of arbitary length
+   Copyright (C) 1991 Free Software Foundation, Inc.
+
+This file is part of the libiberty library.
+Libiberty is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public
+License as published by the Free Software Foundation; either
+version 2 of the License, or (at your option) any later version.
+
+Libiberty is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with libiberty; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA.  */
+
+
+/*
+
+NAME
+
+	memmove -- copy memory regions of arbitary length
+
+SYNOPSIS
+
+	void memmove (void *out, const void *in, size_t n);
+
+DESCRIPTION
+
+	Copy LENGTH bytes from memory region pointed to by IN to memory
+	region pointed to by OUT.
+
+	Regions can be overlapping.
+*/
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#ifdef __STDC__
+#include <stddef.h>
+#else
+#define size_t unsigned long
+#endif
+
+void *
+memmove (out, in, length)
+     void *out;
+     const void* in;
+     size_t length;
+{
+    bcopy(in, out, length);
+    return out;
+}
diff --git a/gnu/usr.bin/cvs/src/Makefile.in b/gnu/usr.bin/cvs/src/Makefile.in
index dfcd4d6e8d0..abfa957e279 100644
--- a/gnu/usr.bin/cvs/src/Makefile.in
+++ b/gnu/usr.bin/cvs/src/Makefile.in
@@ -39,7 +39,7 @@ LIBS = @LIBS@
 
 SOURCES = add.c admin.c buffer.c checkin.c checkout.c classify.c client.c \
 commit.c create_adm.c cvsrc.c diff.c edit.c entries.c error.c expand_path.c \
-fileattr.c find_names.c hash.c history.c ignore.c import.c \
+fileattr.c find_names.c hardlink.c hash.c history.c ignore.c import.c \
 lock.c log.c login.c logmsg.c main.c mkmodules.c modules.c myndbm.c no_diff.c \
 parseinfo.c patch.c rcs.c rcscmds.c recurse.c release.c remove.c repos.c \
 root.c rtag.c scramble.c server.c status.c subr.c filesubr.c run.c \
@@ -47,14 +47,14 @@ tag.c update.c watch.c wrapper.c vers_ts.c version.c zlib.c
 
 OBJECTS = add.o admin.o buffer.o checkin.o checkout.o classify.o client.o \
 commit.o create_adm.o cvsrc.o diff.o edit.o entries.o expand_path.o \
-fileattr.o find_names.o hash.o history.o ignore.o import.o \
+fileattr.o find_names.o hardlink.o hash.o history.o ignore.o import.o \
 lock.o log.o login.o logmsg.o main.o mkmodules.o modules.o myndbm.o no_diff.o \
 parseinfo.o patch.o rcs.o rcscmds.o recurse.o release.o remove.o repos.o \
 root.o rtag.o scramble.o server.o status.o tag.o update.o \
 watch.o wrapper.o vers_ts.o \
 subr.o filesubr.o run.o version.o error.o zlib.o
 
-HEADERS = buffer.h cvs.h rcs.h hash.h myndbm.h \
+HEADERS = buffer.h cvs.h rcs.h hardlink.h hash.h myndbm.h \
 	update.h server.h client.h error.h fileattr.h edit.h watch.h
 
 TAGFILES = $(HEADERS) options.h.in $(SOURCES)
@@ -125,7 +125,7 @@ ls:
 .PHONY: ls
 
 clean:
-	/bin/rm -f $(PROGS) *.o core check.log check.plog
+	rm -f $(PROGS) *.o core check.log check.plog
 .PHONY: clean
 
 distclean: clean
diff --git a/gnu/usr.bin/cvs/src/checkout.c b/gnu/usr.bin/cvs/src/checkout.c
index 3c1eef7fe11..46151eb9969 100644
--- a/gnu/usr.bin/cvs/src/checkout.c
+++ b/gnu/usr.bin/cvs/src/checkout.c
@@ -33,6 +33,7 @@
  * edited by the user, if necessary (when the repository is moved, e.g.)
  */
 
+#include <assert.h>
 #include "cvs.h"
 
 static char *findslash PROTO((char *start, char *p));
@@ -431,7 +432,7 @@ struct dir_to_build
 };
 
 static int build_dirs_and_chdir PROTO ((struct dir_to_build *list,
-					int sticky));
+					int sticky, int check_existing_dirs));
 
 static void build_one_dir PROTO ((char *, char *, int));
 
@@ -580,7 +581,11 @@ checkout_proc (pargc, argv, where_orig, mwhere, mfile, shorten,
 	    (void) strcat (where, "/");
 	}
 
-	if (mwhere != NULL)
+	/* If the -d flag in the modules file specified an absolute
+           directory, let the user override it with the command-line
+           -d option. */
+
+	if ((mwhere != NULL) && (! isabsolute (mwhere)))
 	    (void) strcat (where, mwhere);
 	else
 	    (void) strcat (where, argv[0]);
@@ -723,19 +728,39 @@ internal error: %s doesn't start with %s in checkout_proc",
 	/* Make a copy of the repository name to play with. */
 	reposcopy = xstrdup (repository);
 
-	/* FIXME: this should be written in terms of last_component instead
-	   of hardcoding '/'.  This presumably affects OS/2, NT, &c, if
-	   the user specifies '\'.  Likewise for the call to findslash.  */
-	cp = strrchr (where, '/');
-	while (cp != NULL)
+	/* FIXME: this should be written in terms of last_component
+	   instead of hardcoding '/'.  This presumably affects OS/2,
+	   NT, &c, if the user specifies '\'.  Likewise for the call
+	   to findslash.  */
+	cp = where + strlen (where);
+	while (1)
 	{
 	    struct dir_to_build *new;
+
+	    cp = findslash (where, cp - 1);
+	    if (cp == NULL)
+		break;		/* we're done */
+
 	    new = (struct dir_to_build *)
 		xmalloc (sizeof (struct dir_to_build));
 	    new->dirpath = xmalloc (strlen (where));
-	    strncpy (new->dirpath, where, cp - where);
-	    new->dirpath[cp - where] = '\0';
 
+	    /* If the user specified an absolute path for where, the
+               last path element we create should be the top-level
+               directory. */
+
+	    if (cp - where)
+	    {
+		strncpy (new->dirpath, where, cp - where);
+		new->dirpath[cp - where] = '\0';
+	    }
+	    else
+	    {
+		/* where should always be at least one character long. */
+		assert (strlen (where));
+		strcpy (new->dirpath, "/");
+	    }
+	    
 	    /* Now figure out what repository directory to generate.
                The most complete case would be something like this:
 
@@ -813,31 +838,41 @@ internal error: %s doesn't start with %s in checkout_proc",
 	    
 	    new->next = head;
 	    head = new;
-
-	    cp = findslash (where, cp - 1);
 	}
 
 	/* clean up */
 	free (reposcopy);
 
-	/* The top-level CVSADM directory should always be
-           CVSroot_directory.  Create it.
-	
-	   It may be argued that we shouldn't set any sticky bits for
-	   the top-level repository.  FIXME?  */
-	build_one_dir (CVSroot_directory, ".", *pargc <= 1);
-
-	/*
-	 * build dirs on the path if necessary and leave us in the bottom
-	 * directory (where if where was specified) doesn't contain a CVS
-	 * subdir yet, but all the others contain CVS and Entries.Static
-	 * files
-	 */
-	if (build_dirs_and_chdir (head, *pargc <= 1) != 0)
 	{
-	    error (0, 0, "ignoring module %s", omodule);
-	    err = 1;
-	    goto out;
+	    int where_is_absolute = isabsolute (where);
+	    
+	    /* The top-level CVSADM directory should always be
+	       CVSroot_directory.  Create it, but only if WHERE is
+	       relative.  If WHERE is absolute, our current directory
+	       may not have a thing to do with where the sources are
+	       being checked out.  If it does, build_dirs_and_chdir
+	       will take care of creating adm files here. */
+	       
+	    if (! where_is_absolute)
+	    {
+		/* It may be argued that we shouldn't set any sticky
+		   bits for the top-level repository.  FIXME?  */
+		build_one_dir (CVSroot_directory, ".", *pargc <= 1);
+	    }
+
+
+	    /* Build dirs on the path if necessary and leave us in the
+	       bottom directory (where if where was specified) doesn't
+	       contain a CVS subdir yet, but all the others contain
+	       CVS and Entries.Static files */
+
+	    if (build_dirs_and_chdir (head, *pargc <= 1,
+				      where_is_absolute) != 0)
+	    {
+		error (0, 0, "ignoring module %s", omodule);
+		err = 1;
+		goto out;
+	    }
 	}
 
 	/* set up the repository (or make sure the old one matches) */
@@ -969,7 +1004,7 @@ internal error: %s doesn't start with %s in checkout_proc",
 	List *entries;
 
 	/* we are only doing files, so register them */
-	entries = Entries_Open (0);
+	entries = Entries_Open (0, NULL);
 	for (i = 1; i < *pargc; i++)
 	{
 	    char *line;
@@ -1066,13 +1101,22 @@ emptydir_name ()
     return repository;
 }
 
-/* Build all the dirs along the path to DIRS with CVS subdirs with appropriate
-   repositories.  If ->repository is NULL, do not create a CVSADM directory
-   for that subdirectory; just CVS_CHDIR into it.  */
+
+/* Build all the dirs along the path to DIRS with CVS subdirs with
+   appropriate repositories.  If ->repository is NULL, do not create a
+   CVSADM directory for that subdirectory; just CVS_CHDIR into it.  If
+   check_existing_dirs is nonzero, don't create directories if they
+   already exist, and don't try to write adm files in directories
+   where we don't have write permission.  We use this last option
+   primarily when a user has specified an absolute path for checkout
+   -- we will often not have permission to top-level directories, so
+   we shouldn't complain. */
+
 static int
-build_dirs_and_chdir (dirs, sticky)
+build_dirs_and_chdir (dirs, sticky, check_existing_dirs)
     struct dir_to_build *dirs;
     int sticky;
+    int check_existing_dirs;
 {
     int retval = 0;
     struct dir_to_build *nextdir;
@@ -1080,20 +1124,31 @@ build_dirs_and_chdir (dirs, sticky)
     while (dirs != NULL)
     {
 	char *dir = last_component (dirs->dirpath);
+	int dir_is_writeable;
+
+	if ((! check_existing_dirs) || (! isdir (dir)))
+	    mkdir_if_needed (dir);
 
-	mkdir_if_needed (dir);
 	Subdir_Register (NULL, NULL, dir);
+
+	/* This is an expensive call -- only make it if necessary. */
+	if (check_existing_dirs)
+	    dir_is_writeable = iswritable (dir);
+
 	if (CVS_CHDIR (dir) < 0)
 	{
 	    error (0, errno, "cannot chdir to %s", dir);
 	    retval = 1;
 	    goto out;
 	}
-	if (dirs->repository != NULL)
+
+	if ((dirs->repository != NULL)
+	    && ((! check_existing_dirs) || dir_is_writeable))
 	{
 	    build_one_dir (dirs->repository, dirs->dirpath, sticky);
 	    free (dirs->repository);
 	}
+
 	nextdir = dirs->next;
 	free (dirs->dirpath);
 	free (dirs);
diff --git a/gnu/usr.bin/cvs/src/commit.c b/gnu/usr.bin/cvs/src/commit.c
index a7fec5f9bb8..4aa243868a9 100644
--- a/gnu/usr.bin/cvs/src/commit.c
+++ b/gnu/usr.bin/cvs/src/commit.c
@@ -19,6 +19,7 @@
 #include "getline.h"
 #include "edit.h"
 #include "fileattr.h"
+#include "hardlink.h"
 
 static Dtype check_direntproc PROTO ((void *callerdat, char *dir,
 				      char *repos, char *update_dir,
@@ -81,7 +82,6 @@ static List *mulist;
 static char *message;
 static time_t last_register_time;
 
-
 static const char *const commit_usage[] =
 {
     "Usage: %s %s [-nRlf] [-m msg | -F logfile] [-r rev] files...\n",
@@ -622,10 +622,23 @@ commit (argc, argv)
     lock_tree_for_write (argc, argv, local, aflag);
 
     /*
-     * Set up the master update list
+     * Set up the master update list and hard link list
      */
     mulist = getlist ();
 
+#ifdef PRESERVE_PERMISSIONS_SUPPORT
+    if (preserve_perms)
+    {
+	hardlist = getlist ();
+
+	/*
+	 * We need to save the working directory so that
+	 * check_fileproc can construct a full pathname for each file.
+	 */
+	working_dir = xgetwd();
+    }
+#endif
+
     /*
      * Run the recursion processor to verify the files are all up-to-date
      */
@@ -638,6 +651,17 @@ commit (argc, argv)
 	error (1, 0, "correct above errors first!");
     }
 
+#ifdef PRESERVE_PERMISSIONS_SUPPORT
+    if (preserve_perms)
+    {
+	/* hardlist now includes a complete index of the files
+	   to be committed, indexed by inode.  For each inode,
+	   compile a list of the files that are linked to it,
+	   and save this list in each file's hardlink_info node. */
+	(void) walklist (hardlist, cache_hardlinks_proc, NULL);
+    }
+#endif
+
     /*
      * Run the recursion processor to commit the files
      */
@@ -992,6 +1016,43 @@ warning: file `%s' seems to still contain conflict indicators",
 	    ci->options = xstrdup(vers->options);
 	    p->data = (char *) ci;
 	    (void) addnode (cilist, p);
+
+#ifdef PRESERVE_PERMISSIONS_SUPPORT
+	    if (preserve_perms)
+	    {
+		/* Add this file to hardlist, indexed on its inode.  When
+		   we are done, we can find out what files are hardlinked
+		   to a given file by looking up its inode in hardlist. */
+		char *fullpath;
+		Node *linkp;
+		struct hardlink_info *hlinfo;
+
+		/* Get the full pathname of the current file. */
+		fullpath = xmalloc (strlen(working_dir) +
+				    strlen(finfo->fullname) + 2);
+		sprintf (fullpath, "%s/%s", working_dir, finfo->fullname);
+
+		/* To permit following links in subdirectories, files
+                   are keyed on finfo->fullname, not on finfo->name. */
+		linkp = lookup_file_by_inode (fullpath);
+
+		/* If linkp is NULL, the file doesn't exist... maybe
+		   we're doing a remove operation? */
+		if (linkp != NULL)
+		{
+		    /* Create a new hardlink_info node, which will record
+		       the current file's status and the links listed in its
+		       `hardlinks' delta field.  We will append this
+		       hardlink_info node to the appropriate hardlist entry. */
+		    hlinfo = (struct hardlink_info *)
+			xmalloc (sizeof (struct hardlink_info));
+		    hlinfo->status = status;
+		    hlinfo->links = NULL;
+		    linkp->data = (char *) hlinfo;
+		}
+	    }
+#endif
+
 	    break;
 	case T_UNKNOWN:
 	    error (0, 0, "nothing known about `%s'", finfo->fullname);
@@ -1280,8 +1341,9 @@ commit_fileproc (callerdat, finfo)
 			    /* Doesn't matter, it won't get checked.  */
 			    SERVER_UPDATED,
 
-			    (struct stat *) NULL,
-			    (unsigned char *) NULL);
+			    (mode_t) -1,
+			    (unsigned char *) NULL,
+			    (struct buffer *) NULL);
 	}
 #endif
     }
@@ -1645,9 +1707,8 @@ remove_file (finfo, tag, message)
 			    (RCSCHECKOUTPROC) NULL, (void *) NULL);
     if (retcode != 0)
     {
-	if (!quiet)
-	    error (0, retcode == -1 ? errno : 0,
-		   "failed to check out `%s'", finfo->fullname);
+	error (0, 0,
+	       "failed to check out `%s'", finfo->fullname);
 	return (1);
     }
 
@@ -1981,13 +2042,21 @@ internal error: `%s' didn't move out of the attic",
     if (tag && newfile)
     {
 	char *tmp;
+	FILE *fp;
 
 	/* move the new file out of the way. */
 	fname = xmalloc (strlen (file) + sizeof (CVSADM)
 			 + sizeof (CVSPREFIX) + 10);
 	(void) sprintf (fname, "%s/%s%s", CVSADM, CVSPREFIX, file);
 	rename_file (file, fname);
-	copy_file (DEVNULL, file);
+
+	/* Create empty FILE.  Can't use copy_file with a DEVNULL
+	   argument -- copy_file now ignores device files. */
+	fp = fopen (file, "w");
+	if (fp == NULL)
+	    error (1, errno, "cannot open %s for writing", file);
+	if (fclose (fp) < 0)
+	    error (0, errno, "cannot close %s", file);
 
 	tmp = xmalloc (strlen (file) + strlen (tag) + 80);
 	/* commit a dead revision. */
@@ -2156,18 +2225,31 @@ lock_RCS (user, rcs, rev, repository)
     {
 	(void) RCS_lock(rcs, rev, 1);
     }
-    RCS_rewrite (rcs, NULL, NULL);
+
+    /* We used to call RCS_rewrite here, and that might seem
+       appropriate in order to write out the locked revision
+       information.  However, such a call would actually serve no
+       purpose.  CVS locks will prevent any interference from other
+       CVS processes.  The comment above rcs_internal_lockfile
+       explains that it is already unsafe to use RCS and CVS
+       simultaneously.  It follows that writing out the locked
+       revision information here would add no additional security.
+
+       If we ever do care about it, the proper fix is to create the
+       RCS lock file before calling this function, and maintain it
+       until the checkin is complete.
+
+       The call to RCS_lock is still required at present, since in
+       some cases RCS_checkin will determine which revision to check
+       in by looking for a lock.  FIXME: This is rather roundabout,
+       and a more straightforward approach would probably be easier to
+       understand.  */
 
     if (err == 0)
     {
 	if (sbranch != NULL)
 	    free (sbranch);
-	if (branch)
-	{
-	    sbranch = branch;
-	}
-	else
-	    sbranch = NULL;
+	sbranch = branch;
 	return (0);
     }
 
@@ -2182,7 +2264,8 @@ lock_RCS (user, rcs, rev, repository)
 
 /* Called when "add"ing files to the RCS respository.  It doesn't seem to
    be possible to get RCS to use the right mode, so we change it after
-   the fact.  */
+   the fact.  TODO: now that RCS has been librarified, we have the power
+   to change this. */
 
 static void
 fix_rcs_modes (rcs, user)
@@ -2192,6 +2275,12 @@ fix_rcs_modes (rcs, user)
     struct stat sb;
     mode_t rcs_mode;
 
+#ifdef PRESERVE_PERMISSIONS_SUPPORT
+    /* Do ye nothing to the modes on a symbolic link. */
+    if (preserve_perms && islink (user))
+	return;
+#endif
+
     if (CVS_STAT (user, &sb) < 0)
     {
 	/* FIXME: Should be ->fullname.  */
@@ -2201,6 +2290,9 @@ fix_rcs_modes (rcs, user)
 
     /* Now we compute the new mode.
 
+       TODO: decide whether this whole thing can/should be skipped
+       when `preserve_perms' is set.  Almost certainly so. -twp
+
        The algorithm that we use is:
 
        Write permission is always off (this is what RCS and CVS have always
diff --git a/gnu/usr.bin/cvs/src/cvs.h b/gnu/usr.bin/cvs/src/cvs.h
index a9e83599590..87f653598f3 100644
--- a/gnu/usr.bin/cvs/src/cvs.h
+++ b/gnu/usr.bin/cvs/src/cvs.h
@@ -406,6 +406,7 @@ int RCS_merge PROTO((RCSNode *, char *, char *, char *, char *, char *));
 #define RCS_FLAGS_DEAD 2
 #define RCS_FLAGS_QUIET 4
 #define RCS_FLAGS_MODTIME 8
+#define RCS_FLAGS_KEEPFILE 16
 
 extern int RCS_exec_rcsdiff PROTO ((RCSNode *rcsfile,
 				    char *opts, char *options,
@@ -426,7 +427,7 @@ DBM *open_module PROTO((void));
 FILE *open_file PROTO((const char *, const char *));
 List *Find_Directories PROTO((char *repository, int which, List *entries));
 void Entries_Close PROTO((List *entries));
-List *Entries_Open PROTO((int aflag));
+List *Entries_Open PROTO ((int aflag, char *update_dir));
 void Subdirs_Known PROTO((List *entries));
 void Subdir_Register PROTO((List *, const char *, const char *));
 void Subdir_Deregister PROTO((List *, const char *, const char *));
@@ -465,10 +466,12 @@ int SIG_register PROTO((int sig, SIGCLEANUPPROC sigcleanup));
 int isdir PROTO((const char *file));
 int isfile PROTO((const char *file));
 int islink PROTO((const char *file));
+int isdevice PROTO ((const char *));
 int isreadable PROTO((const char *file));
 int iswritable PROTO((const char *file));
 int isaccessible PROTO((const char *file, const int mode));
 int isabsolute PROTO((const char *filename));
+char *xreadlink PROTO((const char *link));
 char *last_component PROTO((char *path));
 char *get_homedir PROTO ((void));
 char *cvs_temp_name PROTO ((void));
@@ -731,6 +734,9 @@ void freevers_ts PROTO ((Vers_TS ** versp));
 int Checkin PROTO ((int type, struct file_info *finfo, char *rcs, char *rev,
 		    char *tag, char *options, char *message));
 int No_Difference PROTO ((struct file_info *finfo, Vers_TS *vers));
+/* TODO: can the finfo argument to special_file_mismatch be changed? -twp */
+int special_file_mismatch PROTO ((struct file_info *finfo,
+				  char *rev1, char *rev2));
 
 /* CVSADM_BASEREV stuff, from entries.c.  */
 extern char *base_get PROTO ((struct file_info *));
diff --git a/gnu/usr.bin/cvs/src/lock.c b/gnu/usr.bin/cvs/src/lock.c
index 72ae48a5a7a..e6a6be359c6 100644
--- a/gnu/usr.bin/cvs/src/lock.c
+++ b/gnu/usr.bin/cvs/src/lock.c
@@ -704,7 +704,6 @@ lock_obtained (repos)
 static int lock_filesdoneproc PROTO ((void *callerdat, int err,
 				      char *repository, char *update_dir,
 				      List *entries));
-static int fsortcmp PROTO((const Node * p, const Node * q));
 
 /*
  * Create a list of repositories to lock
@@ -733,17 +732,6 @@ lock_filesdoneproc (callerdat, err, repository, update_dir, entries)
     return (err);
 }
 
-/*
- * compare two lock list nodes (for sort)
- */
-static int
-fsortcmp (p, q)
-    const Node *p;
-    const Node *q;
-{
-    return (strcmp (p->key, q->key));
-}
-
 void
 lock_tree_for_write (argc, argv, local, aflag)
     int argc;
diff --git a/gnu/usr.bin/cvs/src/main.c b/gnu/usr.bin/cvs/src/main.c
index 7e111bed2b6..3f90e6973b7 100644
--- a/gnu/usr.bin/cvs/src/main.c
+++ b/gnu/usr.bin/cvs/src/main.c
@@ -528,7 +528,7 @@ main (argc, argv)
 		(void) fputs (config_string, stdout);
 		(void) fputs ("\n", stdout);
 		(void) fputs ("\
-Copyright (c) 1989-1997 Brian Berliner, david d `zoo' zuhn, \n\
+Copyright (c) 1989-1998 Brian Berliner, david d `zoo' zuhn, \n\
                         Jeff Polk, and other authors\n", stdout);
 		(void) fputs ("\n", stdout);
 		(void) fputs ("CVS may be copied only under the terms of the GNU General Public License,\n", stdout);
diff --git a/gnu/usr.bin/cvs/src/mkmodules.c b/gnu/usr.bin/cvs/src/mkmodules.c
index bb95d592532..2ec62d2aff3 100644
--- a/gnu/usr.bin/cvs/src/mkmodules.c
+++ b/gnu/usr.bin/cvs/src/mkmodules.c
@@ -279,10 +279,17 @@ static const char *const modules_contents[] = {
 static const char *const config_contents[] = {
     "# Set this to \"no\" if pserver shouldn't check system users/passwords\n",
     "#SystemAuth=no\n",
+    "\n",
+    "# Set `PreservePermissions' to `yes' to save file status information\n",
+    "# in the repository.\n",
+    "#PreservePermissions=no\n",
+    "\n",
     "# Set this to the name of a local tag to use in addition to Id\n",
     "#tag=OurTag\n",
+    "\n",
     "# Set this to the default umask to use when creating files and directories\n",
     "#umask=002\n",
+    "\n",
     "# Set this to the default data resource limit to use\n",
     "#dlimit=65536\n",
     NULL
@@ -544,7 +551,7 @@ checkout_file (file, temp)
 			    (RCSCHECKOUTPROC) NULL, (void *) NULL);
     if (retcode != 0)
     {
-	error (0, retcode == -1 ? errno : 0, "failed to check out %s file",
+	error (0, 0, "failed to check out %s file",
 	       file);
     }
     freercsnode (&rcsnode);
diff --git a/gnu/usr.bin/cvs/src/parseinfo.c b/gnu/usr.bin/cvs/src/parseinfo.c
index cb3c0ee3b02..6ae074e4e4f 100644
--- a/gnu/usr.bin/cvs/src/parseinfo.c
+++ b/gnu/usr.bin/cvs/src/parseinfo.c
@@ -350,6 +350,26 @@ parse_config (cvsroot)
 	    }
 #endif /* BSD */
 	}
+	else if (strcmp (line, "PreservePermissions") == 0)
+	{
+	    if (strcmp (p, "no") == 0)
+		preserve_perms = 0;
+	    else if (strcmp (p, "yes") == 0)
+	    {
+#ifdef PRESERVE_PERMISSIONS_SUPPORT
+		preserve_perms = 1;
+#else
+		error (0, 0, "\
+warning: this CVS does not support PreservePermissions");
+#endif
+	    }
+	    else
+	    {
+		error (0, 0, "unrecognized value '%s' for PreservePermissions",
+		       p);
+		goto error_return;
+	    }
+	}
 	else
 	{
 	    /* We may be dealing with a keyword which was added in a
diff --git a/gnu/usr.bin/cvs/src/patch.c b/gnu/usr.bin/cvs/src/patch.c
index 9d091c34b6f..9f56b627bfa 100644
--- a/gnu/usr.bin/cvs/src/patch.c
+++ b/gnu/usr.bin/cvs/src/patch.c
@@ -499,23 +499,43 @@ patch_fileproc (callerdat, finfo)
 	ret = 0;
 	goto out2;
     }
+
+    /* Create 3 empty files.  I'm not really sure there is any advantage
+       to doing so now rather than just waiting until later.  */
     tmpfile1 = cvs_temp_name ();
-    if ((fp1 = CVS_FOPEN (tmpfile1, "w+")) != NULL)
-	(void) fclose (fp1);
+    fp1 = CVS_FOPEN (tmpfile1, "w+");
+    if (fp1 == NULL)
+    {
+	error (0, errno, "cannot create temporary file %s", tmpfile1);
+	ret = 1;
+	goto out;
+    }
+    else
+	if (fclose (fp1) < 0)
+	    error (0, errno, "warning: cannot close %s", tmpfile1);
     tmpfile2 = cvs_temp_name ();
-    if ((fp2 = CVS_FOPEN (tmpfile2, "w+")) != NULL)
-	(void) fclose (fp2);
+    fp2 = CVS_FOPEN (tmpfile2, "w+");
+    if (fp2 == NULL)
+    {
+	error (0, errno, "cannot create temporary file %s", tmpfile2);
+	ret = 1;
+	goto out;
+    }
+    else
+	if (fclose (fp2) < 0)
+	    error (0, errno, "warning: cannot close %s", tmpfile2);
     tmpfile3 = cvs_temp_name ();
-    if ((fp3 = CVS_FOPEN (tmpfile3, "w+")) != NULL)
-	(void) fclose (fp3);
-    if (fp1 == NULL || fp2 == NULL || fp3 == NULL)
+    fp3 = CVS_FOPEN (tmpfile3, "w+");
+    if (fp3 == NULL)
     {
-	/* FIXME: should be printing a proper error message, with errno-based
-	   message, and the filename which we could not create.  */
-	error (0, 0, "cannot create temporary files");
+	error (0, errno, "cannot create temporary file %s", tmpfile3);
 	ret = 1;
 	goto out;
     }
+    else
+	if (fclose (fp3) < 0)
+	    error (0, errno, "warning: cannot close %s", tmpfile3);
+
     if (vers_tag != NULL)
     {
 	retcode = RCS_checkout (rcsfile, (char *) NULL, vers_tag,
@@ -523,9 +543,8 @@ patch_fileproc (callerdat, finfo)
 				(RCSCHECKOUTPROC) NULL, (void *) NULL);
 	if (retcode != 0)
 	{
-	    if (!really_quiet)
-		error (retcode == -1 ? 1 : 0, retcode == -1 ? errno : 0,
-		       "co of revision %s in %s failed", vers_tag, rcs);
+	    error (0, 0,
+		   "cannot check out revision %s of %s", vers_tag, rcs);
 	    ret = 1;
 	    goto out;
 	}
@@ -548,9 +567,8 @@ patch_fileproc (callerdat, finfo)
 				(RCSCHECKOUTPROC) NULL, (void *) NULL);
 	if (retcode != 0)
 	{
-	    if (!really_quiet)
-		error (retcode == -1 ? 1 : 0, retcode == -1 ? errno : 0,
-		       "co of revision %s in %s failed", vers_head, rcs);
+	    error (0, 0,
+		   "cannot check out revision %s of %s", vers_head, rcs);
 	    ret = 1;
 	    goto out;
 	}
@@ -584,10 +602,16 @@ patch_fileproc (callerdat, finfo)
 	    if (getline (&line1, &line1_chars_allocated, fp) < 0 ||
 		getline (&line2, &line2_chars_allocated, fp) < 0)
 	    {
-		error (0, errno, "failed to read diff file header %s for %s",
-		       tmpfile3, rcs);
+		if (feof (fp))
+		    error (0, 0, "\
+failed to read diff file header %s for %s: end of file", tmpfile3, rcs);
+		else
+		    error (0, errno,
+			   "failed to read diff file header %s for %s",
+			   tmpfile3, rcs);
 		ret = 1;
-		(void) fclose (fp);
+		if (fclose (fp) < 0)
+		    error (0, errno, "error closing %s", tmpfile3);
 		goto out;
 	    }
 	    if (!unidiff)
@@ -599,7 +623,8 @@ patch_fileproc (callerdat, finfo)
 		{
 		    error (0, 0, "invalid diff header for %s", rcs);
 		    ret = 1;
-		    (void) fclose (fp);
+		    if (fclose (fp) < 0)
+			error (0, errno, "error closing %s", tmpfile3);
 		    goto out;
 		}
 	    }
@@ -612,7 +637,8 @@ patch_fileproc (callerdat, finfo)
 		{
 		    error (0, 0, "invalid unidiff header for %s", rcs);
 		    ret = 1;
-		    (void) fclose (fp);
+		    if (fclose (fp) < 0)
+			error (0, errno, "error closing %s", tmpfile3);
 		    goto out;
 		}
 	    }
diff --git a/gnu/usr.bin/cvs/src/rcs.c b/gnu/usr.bin/cvs/src/rcs.c
index 23d7e97b8e1..29461b69d3f 100644
--- a/gnu/usr.bin/cvs/src/rcs.c
+++ b/gnu/usr.bin/cvs/src/rcs.c
@@ -11,6 +11,9 @@
 #include <assert.h>
 #include "cvs.h"
 #include "edit.h"
+#include "hardlink.h"
+
+int preserve_perms = 0;
 
 /* The RCS -k options, and a set of enums that must match the array.
    These come first so that we can use enum kflag in function
@@ -19,11 +22,57 @@ static const char *const kflags[] =
   {"kv", "kvl", "k", "v", "o", "b", (char *) NULL};
 enum kflag { KFLAG_KV = 0, KFLAG_KVL, KFLAG_K, KFLAG_V, KFLAG_O, KFLAG_B };
 
+/* A structure we use to buffer the contents of an RCS file.  The
+   various fields are only referenced directly by the rcsbuf_*
+   functions.  We declare the struct here so that we can allocate it
+   on the stack, rather than in memory.  */
+
+struct rcsbuffer
+{
+    /* Points to the current position in the buffer.  */
+    char *ptr;
+    /* Points just after the last valid character in the buffer.  */
+    char *ptrend;
+    /* The file.  */
+    FILE *fp;
+    /* The name of the file, used for error messages.  */
+    const char *filename;
+    /* The starting file position of the data in the buffer.  */
+    unsigned long pos;
+    /* The length of the value.  */
+    size_t vlen;
+    /* Whether the value contains an '@' string.  If so, we can not
+       compress whitespace characters.  */
+    int at_string;
+    /* The number of embedded '@' characters in an '@' string.  If
+       this is non-zero, we must search the string for pairs of '@'
+       and convert them to a single '@'.  */
+    int embedded_at;
+};
+
 static RCSNode *RCS_parsercsfile_i PROTO((FILE * fp, const char *rcsfile));
 static char *RCS_getdatebranch PROTO((RCSNode * rcs, char *date, char *branch));
-static int getrcskey PROTO((FILE * fp, char **keyp, char **valp,
-			    size_t *lenp));
-static void getrcsrev PROTO ((FILE *fp, char **revp));
+static void rcsbuf_open PROTO ((struct rcsbuffer *, FILE *fp,
+				const char *filename, unsigned long pos));
+static void rcsbuf_close PROTO ((struct rcsbuffer *));
+static int rcsbuf_getkey PROTO ((struct rcsbuffer *, char **keyp,
+				 char **valp));
+static int rcsbuf_getrevnum PROTO ((struct rcsbuffer *, char **revp));
+static char *rcsbuf_fill PROTO ((struct rcsbuffer *, char *ptr, char **keyp,
+				 char **valp));
+static char *rcsbuf_valcopy PROTO ((struct rcsbuffer *, char *val, int polish,
+				    size_t *lenp));
+static void rcsbuf_valpolish PROTO ((struct rcsbuffer *, char *val, int polish,
+				     size_t *lenp));
+static void rcsbuf_valpolish_internal PROTO ((struct rcsbuffer *, char *to,
+					      const char *from, size_t *lenp));
+static unsigned long rcsbuf_ftell PROTO ((struct rcsbuffer *));
+static void rcsbuf_get_buffered PROTO ((struct rcsbuffer *, char **datap,
+					size_t *lenp));
+static void rcsbuf_cache PROTO ((RCSNode *, struct rcsbuffer *));
+static void rcsbuf_cache_close PROTO ((void));
+static void rcsbuf_cache_open PROTO ((RCSNode *, long, FILE **,
+				      struct rcsbuffer *));
 static int checkmagic_proc PROTO((Node *p, void *closure));
 static void do_branches PROTO((List * list, char *val));
 static void do_symbols PROTO((List * list, char *val));
@@ -40,12 +89,15 @@ static void expand_keywords PROTO((RCSNode *, RCSVers *, const char *,
 static void cmp_file_buffer PROTO((void *, const char *, size_t));
 
 enum rcs_delta_op {RCS_ANNOTATE, RCS_FETCH};
-static void RCS_deltas PROTO ((RCSNode *, FILE *, char *, enum rcs_delta_op,
-			       char **, size_t *, char **, size_t *));
+static void RCS_deltas PROTO ((RCSNode *, FILE *, struct rcsbuffer *, char *,
+			       enum rcs_delta_op, char **, size_t *,
+			       char **, size_t *));
 
 /* Routines for reading, parsing and writing RCS files. */
-static RCSVers *getdelta PROTO ((FILE *, char *));
-static Deltatext *RCS_getdeltatext PROTO ((RCSNode *, FILE *));
+static RCSVers *getdelta PROTO ((struct rcsbuffer *, char *, char **,
+				 char **));
+static Deltatext *RCS_getdeltatext PROTO ((RCSNode *, FILE *,
+					   struct rcsbuffer *));
 static void freedeltatext PROTO ((Deltatext *));
 
 static void RCS_putadmin PROTO ((RCSNode *, FILE *));
@@ -54,13 +106,21 @@ static void RCS_putdesc PROTO ((RCSNode *, FILE *));
 static void putdelta PROTO ((RCSVers *, FILE *));
 static int putrcsfield_proc PROTO ((Node *, void *));
 static int putsymbol_proc PROTO ((Node *, void *));
-static void RCS_copydeltas PROTO ((RCSNode *, FILE *, FILE *, Deltatext *, char *));
+static void RCS_copydeltas PROTO ((RCSNode *, FILE *, struct rcsbuffer *,
+				   FILE *, Deltatext *, char *));
+static int count_delta_actions PROTO ((Node *, void *));
 static void putdeltatext PROTO ((FILE *, Deltatext *));
 
 static FILE *rcs_internal_lockfile PROTO ((char *));
 static void rcs_internal_unlockfile PROTO ((FILE *, char *));
 static char *rcs_lockfilename PROTO ((char *));
 
+/* The RCS file reading functions are called a lot, and they do some
+   string comparisons.  This macro speeds things up a bit by skipping
+   the function call when the first characters are different.  It
+   evaluates its arguments multiple times.  */
+#define STREQ(a, b) ((a)[0] == (b)[0] && strcmp ((a), (b)) == 0)
+
 /*
  * We don't want to use isspace() from the C library because:
  *
@@ -90,7 +150,6 @@ static const char spacetab[] = {
 
 #define whitespace(c)	(spacetab[(unsigned char)c] != 0)
 
-
 /* Parse an rcsfile given a user file name and a repository.  If there is
    an error, we print an error message and return NULL.  If the file
    does not exist, we return NULL without printing anything (I'm not
@@ -106,6 +165,10 @@ RCS_parse (file, repos)
     RCSNode *retval;
     char *rcsfile;
 
+    /* We're creating a new RCSNode, so there is no hope of finding it
+       in the cache.  */
+    rcsbuf_cache_close ();
+
     rcsfile = xmalloc (strlen (repos) + strlen (file)
 		       + sizeof (RCSEXT) + sizeof (CVSATTIC) + 10);
     (void) sprintf (rcsfile, "%s/%s%s", repos, file, RCSEXT);
@@ -115,7 +178,6 @@ RCS_parse (file, repos)
 	if (rcs != NULL) 
 	    rcs->flags |= VALID;
 
-	fclose (fp);
 	retval = rcs;
 	goto out;
     }
@@ -136,7 +198,6 @@ RCS_parse (file, repos)
 	    rcs->flags |= VALID;
 	}
 
-	fclose (fp);
 	retval = rcs;
 	goto out;
     }
@@ -165,7 +226,6 @@ RCS_parse (file, repos)
 	    if (rcs != NULL) 
 		rcs->flags |= VALID;
 
-	    fclose (fp);
 	    free (rcs->path);
 	    rcs->path = found_path;
 	    retval = rcs;
@@ -189,7 +249,6 @@ RCS_parse (file, repos)
 		rcs->flags |= VALID;
 	    }
 
-	    fclose (fp);
 	    free (rcs->path);
 	    rcs->path = found_path;
 	    retval = rcs;
@@ -221,6 +280,10 @@ RCS_parsercsfile (rcsfile)
     FILE *fp;
     RCSNode *rcs;
 
+    /* We're creating a new RCSNode, so there is no hope of finding it
+       in the cache.  */
+    rcsbuf_cache_close ();
+
     /* open the rcsfile */
     if ((fp = CVS_FOPEN (rcsfile, FOPEN_BINARY_READ)) == NULL)
     {
@@ -230,7 +293,6 @@ RCS_parsercsfile (rcsfile)
 
     rcs = RCS_parsercsfile_i (fp, rcsfile);
 
-    fclose (fp);
     return (rcs);
 }
 
@@ -243,6 +305,7 @@ RCS_parsercsfile_i (fp, rcsfile)
     const char *rcsfile;
 {
     RCSNode *rdata;
+    struct rcsbuffer rcsbuf;
     char *key, *value;
 
     /* make a node */
@@ -251,40 +314,32 @@ RCS_parsercsfile_i (fp, rcsfile)
     rdata->refcount = 1;
     rdata->path = xstrdup (rcsfile);
 
-    /* Process HEAD and BRANCH keywords from the RCS header.  
+    /* Process HEAD, BRANCH, and EXPAND keywords from the RCS header.
 
        Most cvs operations on the main branch don't need any more
        information.  Those that do call RCS_reparsercsfile to parse
-       the rest of the header and the deltas.
-
-       People often wonder whether this is inefficient, to open the
-       file once here and once in RCS_reparsercsfile.  Well, it might
-       help a little bit if we kept the file open (I haven't tried
-       timing this myself), but basically the common case, which we
-       want to optimize, is the one in which we call
-       RCS_parsercsfile_i and not RCS_reparsercsfile (for example,
-       "cvs update" on a lot of files most of which are unmodified).
-       So making the case in which we call RCS_reparsercsfile fast is
-       not as important.  */
-
-    if (getrcskey (fp, &key, &value, NULL) == -1 || key == NULL)
+       the rest of the header and the deltas.  */
+
+    rcsbuf_open (&rcsbuf, fp, rcsfile, 0);
+
+    if (! rcsbuf_getkey (&rcsbuf, &key, &value))
 	goto l_error;
-    if (strcmp (key, RCSDESC) == 0)
+    if (STREQ (key, RCSDESC))
 	goto l_error;
 
-    if (strcmp (RCSHEAD, key) == 0 && value != NULL)
-	rdata->head = xstrdup (value);
+    if (STREQ (RCSHEAD, key) && value != NULL)
+	rdata->head = rcsbuf_valcopy (&rcsbuf, value, 0, (size_t *) NULL);
 
-    if (getrcskey (fp, &key, &value, NULL) == -1 || key == NULL)
+    if (! rcsbuf_getkey (&rcsbuf, &key, &value))
 	goto l_error;
-    if (strcmp (key, RCSDESC) == 0)
+    if (STREQ (key, RCSDESC))
 	goto l_error;
 
-    if (strcmp (RCSBRANCH, key) == 0 && value != NULL)
+    if (STREQ (RCSBRANCH, key) && value != NULL)
     {
 	char *cp;
 
-	rdata->branch = xstrdup (value);
+	rdata->branch = rcsbuf_valcopy (&rcsbuf, value, 0, (size_t *) NULL);
 	if ((numdots (rdata->branch) & 1) != 0)
 	{
 	    /* turn it into a branch if it's a revision */
@@ -293,23 +348,43 @@ RCS_parsercsfile_i (fp, rcsfile)
 	}
     }
 
-    rdata->flags |= PARTIAL;
-    return rdata;
-
-l_error:
-    if (!really_quiet)
+    /* Look ahead for expand, stopping when we see desc or a revision
+       number.  */
+    while (1)
     {
-	if (ferror(fp))
-	{
-	    error (1, 0, "error reading `%s'", rcsfile);
-	}
-	else
+	char *cp;
+
+	if (STREQ (RCSEXPAND, key))
 	{
-	    error (0, 0, "`%s' does not appear to be a valid rcs file",
-		   rcsfile);
+	    rdata->expand = rcsbuf_valcopy (&rcsbuf, value, 0,
+					    (size_t *) NULL);
+	    break;
 	}
+
+	for (cp = key; (isdigit (*cp) || *cp == '.') && *cp != '\0'; cp++)
+	    /* do nothing */ ;
+	if (*cp == '\0')
+	    break;
+
+	if (STREQ (RCSDESC, key))
+	    break;
+
+	if (! rcsbuf_getkey (&rcsbuf, &key, &value))
+	    break;
     }
+
+    rdata->flags |= PARTIAL;
+
+    rcsbuf_cache (rdata, &rcsbuf);
+
+    return rdata;
+
+l_error:
+    error (0, 0, "`%s' does not appear to be a valid rcs file",
+	   rcsfile);
+    rcsbuf_close (&rcsbuf);
     freercsnode (&rdata);
+    fclose (fp);
     return (NULL);
 }
 
@@ -321,25 +396,24 @@ l_error:
    If PFP is NULL, close the file when done.  Otherwise, leave it open
    and store the FILE * in *PFP.  */
 void
-RCS_reparsercsfile (rdata, pfp)
+RCS_reparsercsfile (rdata, pfp, rcsbufp)
     RCSNode *rdata;
     FILE **pfp;
+    struct rcsbuffer *rcsbufp;
 {
     FILE *fp;
     char *rcsfile;
-
+    struct rcsbuffer rcsbuf;
     Node *q, *kv;
     RCSVers *vnode;
-    long fpos;
+    int gotkey;
     char *cp;
     char *key, *value;
 
     assert (rdata != NULL);
     rcsfile = rdata->path;
 
-    fp = CVS_FOPEN (rcsfile, FOPEN_BINARY_READ);
-    if (fp == NULL)
-	error (1, 0, "unable to reopen `%s'", rcsfile);
+    rcsbuf_cache_open (rdata, 0, &fp, &rcsbuf);
 
     /* make a node */
     /* This probably shouldn't be done until later: if a file has an
@@ -351,66 +425,68 @@ RCS_reparsercsfile (rdata, pfp)
      * process all the special header information, break out when we get to
      * the first revision delta
      */
+    gotkey = 0;
     for (;;)
     {
-	fpos = ftell (fp);
-
 	/* get the next key/value pair */
-
-	/* if key is NULL here, then the file is missing some headers
-	   or we had trouble reading the file. */
-	if (getrcskey (fp, &key, &value, NULL) == -1 || key == NULL)
+	if (!gotkey)
 	{
-	    if (ferror(fp))
-	    {
-		error (1, 0, "error reading `%s'", rcsfile);
-	    }
-	    else
+	    if (! rcsbuf_getkey (&rcsbuf, &key, &value))
 	    {
 		error (1, 0, "`%s' does not appear to be a valid rcs file",
 		       rcsfile);
 	    }
 	}
 
-	/* Skip head and branch tags; we already have them. */
-	if (strcmp (key, RCSHEAD) == 0 || strcmp (key, RCSBRANCH) == 0)
+	gotkey = 0;
+
+	/* Skip head, branch and expand tags; we already have them. */
+	if (STREQ (key, RCSHEAD)
+	    || STREQ (key, RCSBRANCH)
+	    || STREQ (key, RCSEXPAND))
+	{
 	    continue;
+	}
 
-	if (strcmp (key, "access") == 0)
+	if (STREQ (key, "access"))
 	{
 	    if (value != NULL)
-		rdata->access = xstrdup (value);
+	    {
+		/* We pass the POLISH parameter as 1 because
+                   RCS_addaccess expects nothing but spaces.  FIXME:
+                   It would be easy and more efficient to change
+                   RCS_addaccess.  */
+		rdata->access = rcsbuf_valcopy (&rcsbuf, value, 1,
+						(size_t *) NULL);
+	    }
 	    continue;
 	}
 
 	/* We always save lock information, so that we can handle
            -kkvl correctly when checking out a file. */
-	if (strcmp (key, "locks") == 0)
+	if (STREQ (key, "locks"))
 	{
 	    if (value != NULL)
-		rdata->locks_data = xstrdup (value);
-	    fpos = ftell (fp);
-	    if (getrcskey (fp, &key, &value, NULL) >= 0 &&
-		strcmp (key, "strict") == 0 &&
-		value == NULL)
+		rdata->locks_data = rcsbuf_valcopy (&rcsbuf, value, 0,
+						    (size_t *) NULL);
+	    if (! rcsbuf_getkey (&rcsbuf, &key, &value))
+	    {
+		error (1, 0, "premature end of file reading %s", rcsfile);
+	    }
+	    if (STREQ (key, "strict") && value == NULL)
 	    {
 		rdata->strict_locks = 1;
 	    }
 	    else
-		(void) fseek (fp, fpos, SEEK_SET);
+		gotkey = 1;
 	    continue;
 	}
 
-	if (strcmp (RCSSYMBOLS, key) == 0)
+	if (STREQ (RCSSYMBOLS, key))
 	{
 	    if (value != NULL)
-		rdata->symbols_data = xstrdup(value);
-	    continue;
-	}
-
-	if (strcmp (RCSEXPAND, key) == 0)
-	{
-	    rdata->expand = xstrdup (value);
+		rdata->symbols_data = rcsbuf_valcopy (&rcsbuf, value, 0,
+						      (size_t *) NULL);
 	    continue;
 	}
 
@@ -421,15 +497,19 @@ RCS_reparsercsfile (rdata, pfp)
 	 */
 	for (cp = key; (isdigit (*cp) || *cp == '.') && *cp != '\0'; cp++)
 	     /* do nothing */ ;
-	if (*cp == '\0' && strncmp (RCSDATE, value, strlen (RCSDATE)) == 0)
+	/* Note that when comparing with RCSDATE, we are not massaging
+           VALUE from the string found in the RCS file.  This is OK
+           since we know exactly what to expect.  */
+	if (*cp == '\0' && strncmp (RCSDATE, value, (sizeof RCSDATE) - 1) == 0)
 	    break;
 
-	if (strcmp (key, RCSDESC) == 0)
+	if (STREQ (key, RCSDESC))
 	    break;
 
-	if (strcmp (key, "comment") == 0)
+	if (STREQ (key, "comment"))
 	{
-	    rdata->comment = xstrdup (value);
+	    rdata->comment = rcsbuf_valcopy (&rcsbuf, value, 0,
+					     (size_t *) NULL);
 	    continue;
 	}
 	if (rdata->other == NULL)
@@ -437,7 +517,7 @@ RCS_reparsercsfile (rdata, pfp)
 	kv = getnode ();
 	kv->type = RCSFIELD;
 	kv->key = xstrdup (key);
-	kv->data = xstrdup (value);
+	kv->data = rcsbuf_valcopy (&rcsbuf, value, 1, (size_t *) NULL);
 	if (addnode (rdata->other, kv) != 0)
 	{
 	    error (0, 0, "warning: duplicate key `%s' in RCS file `%s'",
@@ -448,15 +528,11 @@ RCS_reparsercsfile (rdata, pfp)
 	/* if we haven't grabbed it yet, we didn't want it */
     }
 
-    /*
-     * we got out of the loop, so we have the first part of the first
-     * revision delta in our hand key=the revision and value=the date key and
-     * its value
-     */
-    /* First, seek back to the start of the delta block. */
-    (void) fseek (fp, fpos, SEEK_SET);
+    /* We got out of the loop, so we have the first part of the first
+       revision delta in KEY (the revision) and VALUE (the date key
+       and its value).  This is what getdelta expects to receive.  */
 
-    while ((vnode = getdelta (fp, rcsfile)) != NULL)
+    while ((vnode = getdelta (&rcsbuf, rcsfile, &key, &value)) != NULL)
     {
 	/* get the node */
 	q = getnode ();
@@ -476,8 +552,9 @@ RCS_reparsercsfile (rdata, pfp)
 	}
     }
 
-    (void) getrcskey (fp, &key, &value, NULL);
-    if (key != NULL && strcmp (key, RCSDESC) == 0)
+    /* Here KEY and VALUE are whatever caused getdelta to return NULL.  */
+
+    if (STREQ (key, RCSDESC))
     {
 	if (rdata->desc != NULL)
 	{
@@ -486,19 +563,17 @@ RCS_reparsercsfile (rdata, pfp)
 		   key, rcsfile);
 	    free (rdata->desc);
 	}
-	rdata->desc = xstrdup (value);
+	rdata->desc = rcsbuf_valcopy (&rcsbuf, value, 0, (size_t *) NULL);
     }
 
-    rdata->delta_pos = ftell (fp);
+    rdata->delta_pos = rcsbuf_ftell (&rcsbuf);
 
     if (pfp == NULL)
-    {
-	if (fclose (fp) < 0)
-	    error (0, errno, "cannot close %s", rcsfile);
-    }
+	rcsbuf_cache (rdata, &rcsbuf);
     else
     {
 	*pfp = fp;
+	*rcsbufp = rcsbuf;
     }
     rdata->flags &= ~PARTIAL;
 }
@@ -520,31 +595,21 @@ RCS_fully_parse (rcs)
     RCSNode *rcs;
 {
     FILE *fp;
+    struct rcsbuffer rcsbuf;
 
-    RCS_reparsercsfile (rcs, &fp);
+    RCS_reparsercsfile (rcs, &fp, &rcsbuf);
 
     while (1)
     {
-	int c;
 	char *key, *value;
-	size_t vallen;
 	Node *vers;
 	RCSVers *vnode;
 
 	/* Rather than try to keep track of how much information we
            have read, just read to the end of the file.  */
-	do
-	{
-	    c = getc (fp);
-	    if (c == EOF)
-		break;
-	} while (whitespace (c));
-	if (c == EOF)
+	if (! rcsbuf_getrevnum (&rcsbuf, &key))
 	    break;
-	if (ungetc (c, fp) == EOF)
-	    error (1, errno, "ungetc failed");
 
-	getrcsrev (fp, &key);
 	vers = findnode (rcs->versions, key);
 	if (vers == NULL)
 	    error (1, 0,
@@ -553,9 +618,9 @@ RCS_fully_parse (rcs)
 
 	vnode = (RCSVers *) vers->data;
 
-	while (getrcskey (fp, &key, &value, &vallen) >= 0)
+	while (rcsbuf_getkey (&rcsbuf, &key, &value))
 	{
-	    if (strcmp (key, "text") != 0)
+	    if (! STREQ (key, "text"))
 	    {
 		Node *kv;
 
@@ -564,7 +629,7 @@ RCS_fully_parse (rcs)
 		kv = getnode ();
 		kv->type = RCSFIELD;
 		kv->key = xstrdup (key);
-		kv->data = xstrdup (value);
+		kv->data = rcsbuf_valcopy (&rcsbuf, value, 1, (size_t *) NULL);
 		if (addnode (vnode->other, kv) != 0)
 		{
 		    error (0, 0,
@@ -577,7 +642,7 @@ warning: duplicate key `%s' in version `%s' of RCS file `%s'",
 		continue;
 	    }
 
-	    if (strcmp (vnode->version, rcs->head) != 0)
+	    if (! STREQ (vnode->version, rcs->head))
 	    {
 		unsigned long add, del;
 		char buf[50];
@@ -589,8 +654,10 @@ warning: duplicate key `%s' in version `%s' of RCS file `%s'",
 		del = 0;
 		if (value != NULL)
 		{
+		    size_t vallen;
 		    const char *cp;
 
+		    rcsbuf_valpolish (&rcsbuf, value, 0, &vallen);
 		    cp = value;
 		    while (cp < value + vallen)
 		    {
@@ -670,8 +737,7 @@ warning: duplicate key `%s' in version `%s' of RCS file `%s'",
 	}
     }
 
-    if (fclose (fp) < 0)
-	error (0, errno, "cannot close %s", rcs->path);
+    rcsbuf_cache (rcs, &rcsbuf);
 }
 
 /*
@@ -766,353 +832,877 @@ rcsvers_delproc (p)
 {
     free_rcsvers_contents ((RCSVers *) p->data);
 }
+
+/* These functions retrieve keys and values from an RCS file using a
+   buffer.  We use this somewhat complex approach because it turns out
+   that for many common operations, CVS spends most of its time
+   reading keys, so it's worth doing some fairly hairy optimization.  */
 
-/*
- * getrcskey - fill in the key and value from the rcs file the algorithm is
- *             as follows 
- *
- *    o skip whitespace
- *    o fill in key with everything up to next white 
- *      space or semicolon 
- *    o if key == "desc" then key and data are NULL and return -1 
- *    o if key wasn't terminated by a semicolon, skip white space and fill 
- *      in value with everything up to a semicolon 
- *    o compress all whitespace down to a single space 
- *    o if a word starts with @, do funky rcs processing
- *    o strip whitespace off end of value or set value to NULL if it empty 
- *    o return 0 since we found something besides "desc"
- *
- * Sets *KEYP and *VALUEP to point to storage managed by the getrcskey
- * function; the contents are only valid until the next call to
- * getrcskey or getrcsrev.  If LENP is not NULL, this sets *LENP to
- * the length of *VALUEP; this is needed if the string might contain
- * binary data.
- */
+/* The number of bytes we try to read each time we need more data.  */
 
-static char *key = NULL;
-static char *value = NULL;
-static size_t keysize = 0;
-static size_t valsize = 0;
+#define RCSBUF_BUFSIZE (8192)
 
-static int
-getrcskey (fp, keyp, valp, lenp)
+/* The buffer we use to store data.  This grows as needed.  */
+
+static char *rcsbuf_buffer = NULL;
+static size_t rcsbuf_buffer_size = 0;
+
+/* Whether rcsbuf_buffer is in use.  This is used as a sanity check.  */
+
+static int rcsbuf_inuse;
+
+/* Set up to start gathering keys and values from an RCS file.  This
+   initializes RCSBUF.  */
+
+static void
+rcsbuf_open (rcsbuf, fp, filename, pos)
+    struct rcsbuffer *rcsbuf;
     FILE *fp;
+    const char *filename;
+    unsigned long pos;
+{
+    if (rcsbuf_inuse)
+	error (1, 0, "rcsbuf_open: internal error");
+    rcsbuf_inuse = 1;
+
+    if (rcsbuf_buffer_size < RCSBUF_BUFSIZE)
+	expand_string (&rcsbuf_buffer, &rcsbuf_buffer_size, RCSBUF_BUFSIZE);
+
+    rcsbuf->ptr = rcsbuf_buffer;
+    rcsbuf->ptrend = rcsbuf_buffer;
+    rcsbuf->fp = fp;
+    rcsbuf->filename = filename;
+    rcsbuf->pos = pos;
+    rcsbuf->vlen = 0;
+    rcsbuf->at_string = 0;
+    rcsbuf->embedded_at = 0;
+}
+
+/* Stop gathering keys from an RCS file.  */
+
+static void
+rcsbuf_close (rcsbuf)
+    struct rcsbuffer *rcsbuf;
+{
+    if (! rcsbuf_inuse)
+	error (1, 0, "rcsbuf_close: internal error");
+    rcsbuf_inuse = 0;
+}
+
+/* Read a key/value pair from an RCS file.  This sets *KEYP to point
+   to the key, and *VALUEP to point to the value.  A missing or empty
+   value is indicated by setting *VALUEP to NULL.
+
+   This function returns 1 on success, or 0 on EOF.  If there is an
+   error reading the file, or an EOF in an unexpected location, it
+   gives a fatal error.
+
+   This sets *KEYP and *VALUEP to point to storage managed by
+   rcsbuf_getkey.  Moreover, *VALUEP has not been massaged from the
+   RCS format: it may contain embedded whitespace and embedded '@'
+   characters.  Call rcsbuf_valcopy or rcsbuf_valpolish to do
+   appropriate massaging.  */
+
+static int
+rcsbuf_getkey (rcsbuf, keyp, valp)
+    struct rcsbuffer *rcsbuf;
     char **keyp;
     char **valp;
-    size_t *lenp;
 {
-    char *cur, *max;
-    int c;
-    int just_string;
+    register const char * const my_spacetab = spacetab;
+    register char *ptr, *ptrend;
+    char c;
 
-    if (lenp != NULL)
-        *lenp = 0;
+#define my_whitespace(c)	(my_spacetab[(unsigned char)c] != 0)
 
-    /* skip leading whitespace */
-    do
+    rcsbuf->vlen = 0;
+    rcsbuf->at_string = 0;
+    rcsbuf->embedded_at = 0;
+
+    ptr = rcsbuf->ptr;
+    ptrend = rcsbuf->ptrend;
+
+    /* Sanity check.  */
+    if (ptr < rcsbuf_buffer || ptr > rcsbuf_buffer + rcsbuf_buffer_size)
+	abort ();
+
+    /* If the pointer is more than RCSBUF_BUFSIZE bytes into the
+       buffer, move back to the start of the buffer.  This keeps the
+       buffer from growing indefinitely.  */
+    if (ptr - rcsbuf_buffer >= RCSBUF_BUFSIZE)
     {
-	c = getc (fp);
-	if (c == EOF)
-	{
-	    *keyp = (char *) NULL;
-	    *valp = (char *) NULL;
-	    return (-1);
-	}
-    } while (whitespace (c));
+	int len;
+
+	len = ptrend - ptr;
 
-    /* fill in key */
-    cur = key;
-    max = key + keysize;
-    while (!whitespace (c) && c != ';')
+	/* Sanity check: we don't read more than RCSBUF_BUFSIZE bytes
+           at a time, so we can't have more bytes than that past PTR.  */
+	if (len > RCSBUF_BUFSIZE)
+	    abort ();
+
+	/* Update the POS field, which holds the file offset of the
+           first byte in the RCSBUF_BUFFER buffer.  */
+	rcsbuf->pos += ptr - rcsbuf_buffer;
+
+	memcpy (rcsbuf_buffer, ptr, len);
+	ptr = rcsbuf_buffer;
+	ptrend = ptr + len;
+	rcsbuf->ptrend = ptrend;
+    }
+
+    /* Skip leading whitespace.  */
+
+    while (1)
     {
-	if (cur >= max)
+	if (ptr >= ptrend)
 	{
-	    size_t curoff = cur - key;
-	    expand_string (&key, &keysize, keysize + 1);
-	    cur = key + curoff;
-	    max = key + keysize;
+	    ptr = rcsbuf_fill (rcsbuf, ptr, (char **) NULL, (char **) NULL);
+	    if (ptr == NULL)
+		return 0;
+	    ptrend = rcsbuf->ptrend;
 	}
-	*cur++ = c;
 
-	c = getc (fp);
-	if (c == EOF)
+	c = *ptr;
+	if (! my_whitespace (c))
+	    break;
+
+	++ptr;
+    }
+
+    /* We've found the start of the key.  */
+
+    *keyp = ptr;
+
+    if (c != ';')
+    {
+	while (1)
 	{
-	    *keyp = (char *) NULL;
-	    *valp = (char *) NULL;
-	    return (-1);
+	    ++ptr;
+	    if (ptr >= ptrend)
+	    {
+		ptr = rcsbuf_fill (rcsbuf, ptr, keyp, (char **) NULL);
+		if (ptr == NULL)
+		    error (1, 0, "EOF in key in RCS file %s",
+			   rcsbuf->filename);
+		ptrend = rcsbuf->ptrend;
+	    }
+	    c = *ptr;
+	    if (c == ';' || my_whitespace (c))
+		break;
 	}
     }
-    if (cur >= max)
+
+    /* Here *KEYP points to the key in the buffer, C is the character
+       we found at the of the key, and PTR points to the location in
+       the buffer where we found C.  We must set *PTR to \0 in order
+       to terminate the key.  If the key ended with ';', then there is
+       no value.  */
+
+    *ptr = '\0';
+    ++ptr;
+
+    if (c == ';')
     {
-	size_t curoff = cur - key;
-	expand_string (&key, &keysize, keysize + 1);
-	cur = key + curoff;
-	max = key + keysize;
+	*valp = NULL;
+	rcsbuf->ptr = ptr;
+	return 1;
     }
-    *cur = '\0';
 
-    /* skip whitespace between key and val */
-    while (whitespace (c))
+    /* C must be whitespace.  Skip whitespace between the key and the
+       value.  If we find ';' now, there is no value.  */
+
+    while (1)
     {
-	c = getc (fp);
-	if (c == EOF)
+	if (ptr >= ptrend)
 	{
-	    *keyp = (char *) NULL;
-	    *valp = (char *) NULL;
-	    return (-1);
+	    ptr = rcsbuf_fill (rcsbuf, ptr, keyp, (char **) NULL);
+	    if (ptr == NULL)
+		error (1, 0, "EOF while looking for value in RCS file %s",
+		       rcsbuf->filename);
+	    ptrend = rcsbuf->ptrend;
 	}
-    } 
+	c = *ptr;
+	if (c == ';')
+	{
+	    *valp = NULL;
+	    rcsbuf->ptr = ptr + 1;
+	    return 1;
+	}
+	if (! my_whitespace (c))
+	    break;
+	++ptr;
+    }
 
-    /* if we ended key with a semicolon, there is no value */
-    if (c == ';')
+    /* Now PTR points to the start of the value, and C is the first
+       character of the value.  */
+
+    if (c != '@')
+	*valp = ptr;
+    else
     {
-	*keyp = key;
-	*valp = (char *) NULL;
-	return (0);
-    }
+	char *pat;
+	size_t vlen;
 
-    /* otherwise, there might be a value, so fill it in */
-    cur = value;
-    max = value + valsize;
+	/* Optimize the common case of a value composed of a single
+	   '@' string.  */
 
-    just_string = (strcmp (key, RCSDESC) == 0
-		   || strcmp (key, "text") == 0
-		   || strcmp (key, "log") == 0);
+	rcsbuf->at_string = 1;
 
-    /* process the value */
-    for (;;)
-    {
-	/* handle RCS "strings" */
-	if (c == '@') 
+	++ptr;
+
+	*valp = ptr;
+
+	while (1)
 	{
-	    for (;;)
+	    while ((pat = memchr (ptr, '@', ptrend - ptr)) == NULL)
 	    {
-		c = getc (fp);
-		if (c == EOF)
-		{
-		    *keyp = (char *) NULL;
-		    *valp = (char *) NULL;
-		    return (-1);
-		}
+		/* Note that we pass PTREND as the PTR value to
+                   rcsbuf_fill, so that we will wind up setting PTR to
+                   the location corresponding to the old PTREND, so
+                   that we don't search the same bytes again.  */
+		ptr = rcsbuf_fill (rcsbuf, ptrend, keyp, valp);
+		if (ptr == NULL)
+		    error (1, 0,
+			   "EOF while looking for end of string in RCS file %s",
+			   rcsbuf->filename);
+		ptrend = rcsbuf->ptrend;
+	    }
 
-		if (c == '@')
+	    /* Handle the special case of an '@' right at the end of
+               the known bytes.  */
+	    if (pat + 1 >= ptrend)
+	    {
+		/* Note that we pass PAT, not PTR, here.  */
+		pat = rcsbuf_fill (rcsbuf, pat, keyp, valp);
+		if (pat == NULL)
 		{
-		    c = getc (fp);
-		    if (c == EOF)
-		    {
-			*keyp = (char *) NULL;
-			*valp = (char *) NULL;
-			return (-1);
-		    }
-		    
-		    if (c != '@')
-			break;
-		}
+		    /* EOF here is OK; it just means that the last
+		       character of the file was an '@' terminating a
+		       value for a key type which does not require a
+		       trailing ';'.  */
+		    pat = rcsbuf->ptrend - 1;
 
-		if (cur >= max)
-		{
-		    size_t curoff = cur - value;
-		    expand_string (&value, &valsize, valsize + 1);
-		    cur = value + curoff;
-		    max = value + valsize;
 		}
-		*cur++ = c;
+		ptrend = rcsbuf->ptrend;
+
+		/* Note that the value of PTR is bogus here.  This is
+		   OK, because we don't use it.  */
 	    }
+
+	    if (pat + 1 >= ptrend || pat[1] != '@')
+		break;
+
+	    /* We found an '@' pair in the string.  Keep looking.  */
+	    ++rcsbuf->embedded_at;
+	    ptr = pat + 2;
 	}
 
-	/* The syntax for some key-value pairs is different; they
-	   don't end with a semicolon.  */
-	if (just_string)
-	    break;
+	/* Here PAT points to the final '@' in the string.  */
+
+	*pat = '\0';
+
+	vlen = pat - *valp;
+	if (vlen == 0)
+	    *valp = NULL;
+	rcsbuf->vlen = vlen;
+
+	ptr = pat + 1;
+    }
+
+    /* Certain keywords only have a '@' string.  If there is no '@'
+       string, then the old getrcskey function assumed that they had
+       no value, and we do the same.  */
 
-	/* compress whitespace down to a single space */
-	if (whitespace (c))
+    {
+	char *k;
+
+	k = *keyp;
+	if (STREQ (k, RCSDESC)
+	    || STREQ (k, "text")
+	    || STREQ (k, "log"))
 	{
-	    do {
-		c = getc (fp);
-		if (c == EOF)
-		{
-		    *keyp = (char *) NULL;
-		    *valp = (char *) NULL;
-		    return (-1);
-		}
-	    } while (whitespace (c));
+	    if (c != '@')
+		*valp = NULL;
+	    rcsbuf->ptr = ptr;
+	    return 1;
+	}
+    }
 
-	    /* Do not include any trailing whitespace in the value. */
-	    if (c != ';')
+    /* If we've already gathered a '@' string, try to skip whitespace
+       and find a ';'.  */
+    if (c == '@')
+    {
+	while (1)
+	{
+	    char n;
+
+	    if (ptr >= ptrend)
 	    {
-		if (cur >= max)
-		{
-		    size_t curoff = cur - value;
-		    expand_string (&value, &valsize, valsize + 1);
-		    cur = value + curoff;
-		    max = value + valsize;
-		}
-		*cur++ = ' ';
+		ptr = rcsbuf_fill (rcsbuf, ptr, keyp, valp);
+		if (ptr == NULL)
+		    error (1, 0, "EOF in value in RCS file %s",
+			   rcsbuf->filename);
+		ptrend = rcsbuf->ptrend;
+	    }
+	    n = *ptr;
+	    if (n == ';')
+	    {
+		/* We're done.  We already set everything up for this
+                   case above.  */
+		rcsbuf->ptr = ptr + 1;
+		return 1;
 	    }
+	    if (! my_whitespace (n))
+		break;
+	    ++ptr;
 	}
 
-	/* if we got a semi-colon we are done with the entire value */
-	if (c == ';')
-	    break;
+	/* The value extends past the '@' string.  We need to undo the
+           closing of the '@' done in the default case above.  This
+           case never happens in a plain RCS file, but it can happen
+           if user defined phrases are used.  */
+	if (rcsbuf->vlen != 0)
+	    (*valp)[rcsbuf->vlen] = ' ';
+	else
+	    *valp = ptr;
+    }
 
-	if (cur >= max)
+    /* Here we have a value which is not a simple '@' string.  We need
+       to gather up everything until the next ';', including any '@'
+       strings.  *VALP points to the start of the value.  If
+       RCSBUF->VLEN is not zero, then we have already read an '@'
+       string, and PTR points to the data following the '@' string.
+       Otherwise, PTR points to the start of the value.  */
+
+    while (1)
+    {
+	char *start, *psemi, *pat;
+
+	/* Find the ';' which must end the value.  */
+	start = ptr;
+	while ((psemi = memchr (ptr, ';', ptrend - ptr)) == NULL)
 	{
-	    size_t curoff = cur - value;
-	    expand_string (&value, &valsize, valsize + 1);
-	    cur = value + curoff;
-	    max = value + valsize;
+	    int slen;
+
+	    /* Note that we pass PTREND as the PTR value to
+	       rcsbuf_fill, so that we will wind up setting PTR to the
+	       location corresponding to the old PTREND, so that we
+	       don't search the same bytes again.  */
+	    slen = start - *valp;
+	    ptr = rcsbuf_fill (rcsbuf, ptrend, keyp, valp);
+	    if (ptr == NULL)
+		error (1, 0, "EOF in value in RCS file %s", rcsbuf->filename);
+	    start = *valp + slen;
+	    ptrend = rcsbuf->ptrend;
 	}
-	*cur++ = c;
 
-	c = getc (fp);
-	if (c == EOF)
+	/* See if there are any '@' strings in the value.  */
+	pat = memchr (start, '@', psemi - start);
+
+	if (pat == NULL)
 	{
-	    *keyp = (char *) NULL;
-	    *valp = (char *) NULL;
-	    return (-1);
+	    size_t vlen;
+
+	    /* We're done with the value.  Trim any trailing
+               whitespace.  */
+
+	    rcsbuf->ptr = psemi + 1;
+
+	    start = *valp;
+	    while (psemi > start && my_whitespace (psemi[-1]))
+		--psemi;
+	    *psemi = '\0';
+
+	    vlen = psemi - start;
+	    if (vlen == 0)
+		*valp = NULL;
+	    rcsbuf->vlen = vlen;
+
+	    return 1;
 	}
+
+	/* We found an '@' string in the value.  We set
+	   RCSBUF->AT_STRING, which means that we won't be able to
+	   compress whitespace correctly for this type of value.
+	   Since this type of value never arises in a normal RCS file,
+	   this should not be a big deal.  It means that if anybody
+	   adds a phrase which can have both an '@' string and regular
+	   text, they will have to handle whitespace compression
+	   themselves.  */
+
+	rcsbuf->at_string = 1;
+
+	*pat = ' ';
+
+	ptr = pat + 1;
+
+	while (1)
+	{
+	    while ((pat = memchr (ptr, '@', ptrend - ptr)) == NULL)
+	    {
+		/* Note that we pass PTREND as the PTR value to
+                   rcsbuff_fill, so that we will wind up setting PTR
+                   to the location corresponding to the old PTREND, so
+                   that we don't search the same bytes again.  */
+		ptr = rcsbuf_fill (rcsbuf, ptrend, keyp, valp);
+		if (ptr == NULL)
+		    error (1, 0,
+			   "EOF while looking for end of string in RCS file %s",
+			   rcsbuf->filename);
+		ptrend = rcsbuf->ptrend;
+	    }
+
+	    /* Handle the special case of an '@' right at the end of
+               the known bytes.  */
+	    if (pat + 1 >= ptrend)
+	    {
+		ptr = rcsbuf_fill (rcsbuf, ptr, keyp, valp);
+		if (ptr == NULL)
+		    error (1, 0, "EOF in value in RCS file %s",
+			   rcsbuf->filename);
+		ptrend = rcsbuf->ptrend;
+	    }
+
+	    if (pat[1] != '@')
+		break;
+
+	    /* We found an '@' pair in the string.  Keep looking.  */
+	    ++rcsbuf->embedded_at;
+	    ptr = pat + 2;
+	}
+
+	/* Here PAT points to the final '@' in the string.  */
+
+	*pat = ' ';
+
+	ptr = pat + 1;
     }
 
-    /* terminate the string */
-    if (cur >= max)
+#undef my_whitespace
+}
+
+/* Read an RCS revision number from an RCS file.  This sets *REVP to
+   point to the revision number; it will point to space that is
+   managed by the rcsbuf functions, and is only good until the next
+   call to rcsbuf_getkey or rcsbuf_getrevnum.
+
+   This function returns 1 on success, or 0 on EOF.  If there is an
+   error reading the file, or an EOF in an unexpected location, it
+   gives a fatal error.  */
+
+static int
+rcsbuf_getrevnum (rcsbuf, revp)
+    struct rcsbuffer *rcsbuf;
+    char **revp;
+{
+    char *ptr, *ptrend;
+    char c;
+
+    ptr = rcsbuf->ptr;
+    ptrend = rcsbuf->ptrend;
+
+    *revp = NULL;
+
+    /* Skip leading whitespace.  */
+
+    while (1)
     {
-	size_t curoff = cur - value;
-	expand_string (&value, &valsize, valsize + 1);
-	cur = value + curoff;
-	max = value + valsize;
+	if (ptr >= ptrend)
+	{
+	    ptr = rcsbuf_fill (rcsbuf, ptr, (char **) NULL, (char **) NULL);
+	    if (ptr == NULL)
+		return 0;
+	    ptrend = rcsbuf->ptrend;
+	}
+
+	c = *ptr;
+	if (! whitespace (c))
+	    break;
+
+	++ptr;
     }
-    *cur = '\0';
 
-    /* if the string is empty, make it null */
-    if (value && cur != value)
+    if (! isdigit (c) && c != '.')
+	error (1, 0,
+	       "unexpected `%c' reading revision number in RCS file %s",
+	       c, rcsbuf->filename);
+
+    *revp = ptr;
+
+    do
+    {
+	++ptr;
+	if (ptr >= ptrend)
+	{
+	    ptr = rcsbuf_fill (rcsbuf, ptr, revp, (char **) NULL);
+	    if (ptr == NULL)
+		error (1, 0,
+		       "unexpected EOF reading revision number in RCS file %s",
+		       rcsbuf->filename);
+	    ptrend = rcsbuf->ptrend;
+	}
+
+	c = *ptr;
+    }
+    while (isdigit (c) || c == '.');
+
+    if (! whitespace (c))
+	error (1, 0, "unexpected `%c' reading revision number in RCS file %s",
+	       c, rcsbuf->filename);
+
+    *ptr = '\0';
+
+    rcsbuf->ptr = ptr + 1;
+
+    return 1;
+}
+
+/* Fill RCSBUF_BUFFER with bytes from the file associated with RCSBUF,
+   updating PTR and the PTREND field.  If KEYP and *KEYP are not NULL,
+   then *KEYP points into the buffer, and must be adjusted if the
+   buffer is changed.  Likewise for VALP.  Returns the new value of
+   PTR, or NULL on error.  */
+
+static char *
+rcsbuf_fill (rcsbuf, ptr, keyp, valp)
+    struct rcsbuffer *rcsbuf;
+    char *ptr;
+    char **keyp;
+    char **valp;
+{
+    int got;
+
+    if (rcsbuf->ptrend - rcsbuf_buffer + RCSBUF_BUFSIZE > rcsbuf_buffer_size)
+    {
+	int poff, peoff, koff, voff;
+
+	poff = ptr - rcsbuf_buffer;
+	peoff = rcsbuf->ptrend - rcsbuf_buffer;
+	if (keyp != NULL && *keyp != NULL)
+	    koff = *keyp - rcsbuf_buffer;
+	if (valp != NULL && *valp != NULL)
+	    voff = *valp - rcsbuf_buffer;
+
+	expand_string (&rcsbuf_buffer, &rcsbuf_buffer_size,
+		       rcsbuf_buffer_size + RCSBUF_BUFSIZE);
+
+	ptr = rcsbuf_buffer + poff;
+	rcsbuf->ptrend = rcsbuf_buffer + peoff;
+	if (keyp != NULL && *keyp != NULL)
+	    *keyp = rcsbuf_buffer + koff;
+	if (valp != NULL && *valp != NULL)
+	    *valp = rcsbuf_buffer + voff;
+    }
+
+    got = fread (rcsbuf->ptrend, 1, RCSBUF_BUFSIZE, rcsbuf->fp);
+    if (got == 0)
+    {
+	if (ferror (rcsbuf->fp))
+	    error (1, errno, "cannot read %s", rcsbuf->filename);
+	return NULL;
+    }
+
+    rcsbuf->ptrend += got;
+
+    return ptr;
+}
+
+/* Copy the value VAL returned by rcsbuf_getkey into a memory buffer,
+   returning the memory buffer.  Polish the value like
+   rcsbuf_valpolish, q.v.  */
+
+static char *
+rcsbuf_valcopy (rcsbuf, val, polish, lenp)
+    struct rcsbuffer *rcsbuf;
+    char *val;
+    int polish;
+    size_t *lenp;
+{
+    size_t vlen;
+    int embedded_at;
+    char *ret;
+
+    if (val == NULL)
     {
-	*valp = value;
 	if (lenp != NULL)
-	    *lenp = cur - value;
+	    *lenp = 0;
+	return NULL;
     }
-    else
-	*valp = NULL;
-    *keyp = key;
-    return (0);
+
+    vlen = rcsbuf->vlen;
+    embedded_at = rcsbuf->embedded_at;
+
+    ret = xmalloc (vlen - embedded_at + 1);
+
+    if (rcsbuf->at_string ? embedded_at == 0 : ! polish)
+    {
+	/* No special action to take.  */
+	memcpy (ret, val, vlen + 1);
+	if (lenp != NULL)
+	    *lenp = vlen;
+	return ret;
+    }
+
+    rcsbuf_valpolish_internal (rcsbuf, ret, val, lenp);
+    return ret;
 }
 
-/* Read an RCS revision number from FP.  Put a pointer to it in *REVP;
-   it points to space managed by getrcsrev which is only good until
-   the next call to getrcskey or getrcsrev.  */
+/* Polish the value VAL returned by rcsbuf_getkey.  The POLISH
+   parameter is non-zero if multiple embedded whitespace characters
+   should be compressed into a single whitespace character.  Note that
+   leading and trailing whitespace was already removed by
+   rcsbuf_getkey.  Within an '@' string, pairs of '@' characters are
+   compressed into a single '@' character regardless of the value of
+   POLISH.  If LENP is not NULL, set *LENP to the length of the value.  */
+
 static void
-getrcsrev (fp, revp)
-    FILE *fp;
-    char **revp;
+rcsbuf_valpolish (rcsbuf, val, polish, lenp)
+    struct rcsbuffer *rcsbuf;
+    char *val;
+    int polish;
+    size_t *lenp;
 {
-    char *cur;
-    char *max;
-    int c;
+    if (val == NULL)
+    {
+	if (lenp != NULL)
+	    *lenp= 0;
+	return;
+    }
 
-    do {
-	c = getc (fp);
-	if (c == EOF)
+    if (rcsbuf->at_string ? rcsbuf->embedded_at == 0 : ! polish)
+    {
+	/* No special action to take.  */
+	if (lenp != NULL)
+	    *lenp = rcsbuf->vlen;
+	return;
+    }
+
+    rcsbuf_valpolish_internal (rcsbuf, val, val, lenp);
+}
+
+/* Internal polishing routine, called from rcsbuf_valcopy and
+   rcsbuf_valpolish.  */
+
+static void
+rcsbuf_valpolish_internal (rcsbuf, to, from, lenp)
+    struct rcsbuffer *rcsbuf;
+    char *to;
+    const char *from;
+    size_t *lenp;
+{
+    size_t len;
+
+    len = rcsbuf->vlen;
+
+    if (! rcsbuf->at_string)
+    {
+	char *orig_to;
+	size_t clen;
+
+	orig_to = to;
+
+	for (clen = len; clen > 0; ++from, --clen)
 	{
-	    /* FIXME: should be including filename in error message.  */
-	    if (ferror (fp))
-		error (1, errno, "cannot read rcs file");
-	    else
-		error (1, 0, "unexpected end of file reading rcs file");
+	    char c;
+
+	    c = *from;
+	    if (whitespace (c))
+	    {
+		/* Note that we know that clen can not drop to zero
+                   while we have whitespace, because we know there is
+                   no trailing whitespace.  */
+		while (whitespace (from[1]))
+		{
+		    ++from;
+		    --clen;
+		}
+		c = ' ';
+	    }
+	    *to++ = c;
 	}
-    } while (whitespace (c));
 
-    if (!(isdigit (c) || c == '.'))
-	/* FIXME: should be including filename in error message.  */
-	error (1, 0, "error reading rcs file; revision number expected");
+	*to = '\0';
 
-    cur = key;
-    max = key + keysize;
-    while (isdigit (c) || c == '.')
+	if (lenp != NULL)
+	    *lenp = to - orig_to;
+    }
+    else
     {
-	if (cur >= max)
+	const char *orig_from;
+	char *orig_to;
+	int embedded_at;
+	size_t clen;
+
+	orig_from = from;
+	orig_to = to;
+
+	embedded_at = rcsbuf->embedded_at;
+
+	if (lenp != NULL)
+	    *lenp = len - embedded_at;
+
+	for (clen = len; clen > 0; ++from, --clen)
 	{
-	    size_t curoff = cur - key;
-	    expand_string (&key, &keysize, keysize + 1);
-	    cur = key + curoff;
-	    max = key + keysize;
+	    char c;
+
+	    c = *from;
+	    *to++ = c;
+	    if (c == '@')
+	    {
+		++from;
+
+		/* Sanity check.  */
+		if (*from != '@' || clen == 0)
+		    abort ();
+
+		--clen;
+
+		--embedded_at;
+		if (embedded_at == 0)
+		{
+		    /* We've found all the embedded '@' characters.
+                       We can just memcpy the rest of the buffer after
+                       this '@' character.  */
+		    if (orig_to != orig_from)
+			memcpy (to, from + 1, clen - 1);
+		    else
+			memmove (to, from + 1, clen - 1);
+		    from += clen;
+		    to += clen - 1;
+		    break;
+		}
+	    }
 	}
-	*cur++ = c;
 
-	c = getc (fp);
-	if (c == EOF)
+	/* Sanity check.  */
+	if (from != orig_from + len
+	    || to != orig_to + (len - rcsbuf->embedded_at))
 	{
-	    /* FIXME: should be including filename in error message.  */
-	    if (ferror (fp))
-		error (1, errno, "cannot read rcs file");
-	    else
-		error (1, 0, "unexpected end of file reading rcs file");
+	    abort ();
 	}
-    }
 
-    if (cur >= max)
-    {
-	size_t curoff = cur - key;
-	expand_string (&key, &keysize, keysize + 1);
-	cur = key + curoff;
-	max = key + keysize;
+	*to = '\0';
     }
-    *cur = '\0';
-    *revp = key;
 }
 
-/* Like getrcsrev, but don't die on error.  Return the last character
-   read (last call to getc, which may be EOF).  TODO: implement getrcsrev
-   in terms of this function. */
-static int
-getrevnum (fp, revp)
-    FILE *fp;
-    char **revp;
+/* Return the current position of an rcsbuf.  */
+
+static unsigned long
+rcsbuf_ftell (rcsbuf)
+    struct rcsbuffer *rcsbuf;
 {
-    char *cur;
-    char *max;
-    int c;
+    return rcsbuf->pos + (rcsbuf->ptr - rcsbuf_buffer);
+}
 
-    *revp = NULL;
-    do {
-	c = getc (fp);
-	if (c == EOF)
-	    return c;
-    } while (whitespace (c));
+/* Return a pointer to any data buffered for RCSBUF, along with the
+   length.  */
+
+static void
+rcsbuf_get_buffered (rcsbuf, datap, lenp)
+    struct rcsbuffer *rcsbuf;
+    char **datap;
+    size_t *lenp;
+{
+    *datap = rcsbuf->ptr;
+    *lenp = rcsbuf->ptrend - rcsbuf->ptr;
+}
 
-    if (!(isdigit (c) || c == '.'))
-	return c;
+/* CVS optimizes by quickly reading some header information from a
+   file.  If it decides it needs to do more with the file, it reopens
+   it.  We speed that up here by maintaining a cache of a single open
+   file, to save the time it takes to reopen the file in the common
+   case.  */
 
-    cur = key;
-    max = key + keysize;
-    while (isdigit (c) || c == '.')
+static RCSNode *cached_rcs;
+static struct rcsbuffer cached_rcsbuf;
+
+/* Cache RCS and RCSBUF.  This takes responsibility for closing
+   RCSBUF->FP.  */
+
+static void
+rcsbuf_cache (rcs, rcsbuf)
+    RCSNode *rcs;
+    struct rcsbuffer *rcsbuf;
+{
+    if (cached_rcs != NULL)
+	rcsbuf_cache_close ();
+    cached_rcs = rcs;
+    ++rcs->refcount;
+    cached_rcsbuf = *rcsbuf;
+}
+
+/* If there is anything in the cache, close it.  */
+
+static void
+rcsbuf_cache_close ()
+{
+    if (cached_rcs != NULL)
     {
-	if (cur >= max)
+	if (fclose (cached_rcsbuf.fp) != 0)
+	    error (0, errno, "cannot close %s", cached_rcsbuf.filename);
+	rcsbuf_close (&cached_rcsbuf);
+	freercsnode (&cached_rcs);
+	cached_rcs = NULL;
+    }
+}
+
+/* Open an rcsbuffer for RCS, getting it from the cache if possible.
+   Set *FPP to the file, and *RCSBUFP to the rcsbuf.  The file should
+   be put at position POS.  */
+
+static void
+rcsbuf_cache_open (rcs, pos, pfp, prcsbuf)
+    RCSNode *rcs;
+    long pos;
+    FILE **pfp;
+    struct rcsbuffer *prcsbuf;
+{
+    if (cached_rcs == rcs)
+    {
+	if (rcsbuf_ftell (&cached_rcsbuf) != pos)
 	{
-	    size_t curoff = cur - key;
-	    expand_string (&key, &keysize, keysize + 1);
-	    cur = key + curoff;
-	    max = key + keysize;
+	    if (fseek (cached_rcsbuf.fp, pos, SEEK_SET) != 0)
+		error (1, 0, "cannot fseek RCS file %s",
+		       cached_rcsbuf.filename);
+	    cached_rcsbuf.ptr = rcsbuf_buffer;
+	    cached_rcsbuf.ptrend = rcsbuf_buffer;
+	    cached_rcsbuf.pos = pos;
 	}
-	*cur = c;
+	*pfp = cached_rcsbuf.fp;
 
-	c = getc (fp);
-	if (c == EOF)
-	    break;
-	cur++;
-    }
+	/* When RCS_parse opens a file using fopen_case, it frees the
+           filename which we cached in CACHED_RCSBUF and stores a new
+           file name in RCS->PATH.  We avoid problems here by always
+           copying the filename over.  FIXME: This is hackish.  */
+	cached_rcsbuf.filename = rcs->path;
+
+	*prcsbuf = cached_rcsbuf;
+
+	cached_rcs = NULL;
 
-    if (cur >= max)
+	/* Removing RCS from the cache removes a reference to it.  */
+	--rcs->refcount;
+	if (rcs->refcount <= 0)
+	    error (1, 0, "rcsbuf_cache_open: internal error");
+    }
+    else
     {
-	size_t curoff = cur - key;
-	expand_string (&key, &keysize, keysize + 1);
-	cur = key + curoff;
-	max = key + keysize;
+	if (cached_rcs != NULL)
+	    rcsbuf_cache_close ();
+
+	*pfp = CVS_FOPEN (rcs->path, FOPEN_BINARY_READ);
+	if (*pfp == NULL)
+	    error (1, 0, "unable to reopen `%s'", rcs->path);
+	if (pos != 0)
+	{
+	    if (fseek (*pfp, pos, SEEK_SET) != 0)
+		error (1, 0, "cannot fseek RCS file %s", rcs->path);
+	}
+	rcsbuf_open (prcsbuf, *pfp, rcs->path, pos);
     }
-    *cur = '\0';
-    *revp = key;
-    return c;
 }
 
+
 /*
  * process the symbols list of the rcs file
  */
@@ -1312,10 +1902,10 @@ RCS_gettag (rcs, symtag, force_tag_match, simple_tag)
 
     /* XXX this is probably not necessary, --jtc */
     if (rcs->flags & PARTIAL) 
-	RCS_reparsercsfile (rcs, NULL);
+	RCS_reparsercsfile (rcs, (FILE **) NULL, (struct rcsbuffer *) NULL);
 
     /* If tag is "HEAD", special case to get head RCS revision */
-    if (tag && (strcmp (tag, TAG_HEAD) == 0 || *tag == '\0'))
+    if (tag && (STREQ (tag, TAG_HEAD) || *tag == '\0'))
 #if 0 /* This #if 0 is only in the Cygnus code.  Why?  Death support?  */
 	if (force_tag_match && (rcs->flags & VALID) && (rcs->flags & INATTIC))
 	    return ((char *) NULL);	/* head request for removed file */
@@ -1501,7 +2091,7 @@ checkmagic_proc (p, closure)
     Node *p;
     void *closure;
 {
-    if (strcmp (check_rev, p->data) == 0)
+    if (STREQ (check_rev, p->data))
 	return (1);
     else
 	return (0);
@@ -1655,7 +2245,7 @@ RCS_getbranch (rcs, tag, force_tag_match)
     assert (rcs != NULL);
 
     if (rcs->flags & PARTIAL)
-	RCS_reparsercsfile (rcs, NULL);
+	RCS_reparsercsfile (rcs, (FILE **) NULL, (struct rcsbuffer *) NULL);
 
     /* find out if the tag contains a dot, or is on the trunk */
     cp = strrchr (tag, '.');
@@ -1873,7 +2463,7 @@ RCS_getdate (rcs, date, force_tag_match)
     assert (rcs != NULL);
 
     if (rcs->flags & PARTIAL)
-	RCS_reparsercsfile (rcs, NULL);
+	RCS_reparsercsfile (rcs, (FILE **) NULL, (struct rcsbuffer *) NULL);
 
     /* if the head is on a branch, try the branch first */
     if (rcs->branch != NULL)
@@ -1911,7 +2501,7 @@ RCS_getdate (rcs, date, force_tag_match)
      */
 
     /* if we found what we're looking for, and it's not 1.1 return it */
-    if (cur_rev != NULL && strcmp (cur_rev, "1.1") != 0)
+    if (cur_rev != NULL && ! STREQ (cur_rev, "1.1"))
 	return (xstrdup (cur_rev));
 
     /* look on the vendor branch */
@@ -1960,7 +2550,7 @@ RCS_getdatebranch (rcs, date, branch)
     assert (rcs != NULL);
 
     if (rcs->flags & PARTIAL)
-	RCS_reparsercsfile (rcs, NULL);
+	RCS_reparsercsfile (rcs, (FILE **) NULL, (struct rcsbuffer *) NULL);
 
     p = findnode (rcs->versions, xrev);
     free (xrev);
@@ -2057,7 +2647,7 @@ RCS_getrevtime (rcs, rev, date, fudge)
     assert (rcs != NULL);
 
     if (rcs->flags & PARTIAL)
-	RCS_reparsercsfile (rcs, NULL);
+	RCS_reparsercsfile (rcs, (FILE **) NULL, (struct rcsbuffer *) NULL);
 
     /* look up the revision */
     p = findnode (rcs->versions, rev);
@@ -2109,7 +2699,7 @@ RCS_getlocks (rcs)
     assert(rcs != NULL);
 
     if (rcs->flags & PARTIAL)
-	RCS_reparsercsfile (rcs, NULL);
+	RCS_reparsercsfile (rcs, (FILE **) NULL, (struct rcsbuffer *) NULL);
 
     if (rcs->locks_data) {
 	rcs->locks = getlist ();
@@ -2128,7 +2718,7 @@ RCS_symbols(rcs)
     assert(rcs != NULL);
 
     if (rcs->flags & PARTIAL)
-	RCS_reparsercsfile (rcs, NULL);
+	RCS_reparsercsfile (rcs, (FILE **) NULL, (struct rcsbuffer *) NULL);
 
     if (rcs->symbols_data) {
 	rcs->symbols = getlist ();
@@ -2150,7 +2740,7 @@ translate_symtag (rcs, tag)
     const char *tag;
 {
     if (rcs->flags & PARTIAL)
-	RCS_reparsercsfile (rcs, NULL);
+	RCS_reparsercsfile (rcs, (FILE **) NULL, (struct rcsbuffer *) NULL);
 
     if (rcs->symbols != NULL)
     {
@@ -2234,7 +2824,7 @@ RCS_check_kflag (arg)
     {
 	for (cpp = kflags; *cpp != NULL; cpp++)
 	{
-	    if (strcmp (arg, *cpp) == 0)
+	    if (STREQ (arg, *cpp))
 		break;
 	}
     }
@@ -2292,7 +2882,7 @@ RCS_isdead (rcs, tag)
     RCSVers *version;
 
     if (rcs->flags & PARTIAL)
-	RCS_reparsercsfile (rcs, NULL);
+	RCS_reparsercsfile (rcs, (FILE **) NULL, (struct rcsbuffer *) NULL);
 
     p = findnode (rcs->versions, tag);
     if (p == NULL)
@@ -2312,8 +2902,6 @@ RCS_getexpand (rcs)
     RCSNode *rcs;
 {
     assert (rcs != NULL);
-    if (rcs->flags & PARTIAL)
-	RCS_reparsercsfile (rcs, NULL);
     return rcs->expand;
 }
 
@@ -2910,7 +3498,16 @@ expand_keywords (rcs, ver, name, log, loglen, expand, buf, len, retbuf, retlen)
 
    OPTIONS is a string such as "-kb" or "-kv" for keyword expansion
    options.  It may be NULL to use the default expansion mode of the
-   file, typically "-kkv".  */
+   file, typically "-kkv".
+
+   On an error which prevented checking out the file, either print a
+   nonfatal error and return 1, or give a fatal error.  On success,
+   return 0.  */
+
+/* This function mimics the behavior of `rcs co' almost exactly.  The
+   chief difference is in its support for preserving file ownership,
+   permissions, and special files across checkin and checkout -- see
+   comments in RCS_checkin for some issues about this. -twp */
 
 int
 RCS_checkout (rcs, workfile, rev, nametag, options, sout, pfn, callerdat)
@@ -2925,15 +3522,27 @@ RCS_checkout (rcs, workfile, rev, nametag, options, sout, pfn, callerdat)
 {
     int free_rev = 0;
     enum kflag expand;
-    FILE *fp;
+    FILE *fp, *ofp;
     struct stat sb;
+    struct rcsbuffer rcsbuf;
     char *key;
     char *value;
     size_t len;
     int free_value = 0;
     char *log = NULL;
     size_t loglen;
-    FILE *ofp;
+    Node *vp = NULL;
+#ifdef PRESERVE_PERMISSIONS_SUPPORT
+    uid_t rcs_owner;
+    gid_t rcs_group;
+    mode_t rcs_mode;
+    int change_rcs_owner = 0;
+    int change_rcs_group = 0;
+    int change_rcs_mode = 0;
+    int special_file = 0;
+    unsigned long devnum_long;
+    dev_t devnum = 0;
+#endif
 
     if (trace)
     {
@@ -2970,34 +3579,25 @@ RCS_checkout (rcs, workfile, rev, nametag, options, sout, pfn, callerdat)
 	free_rev = 1;
     }
 
-    if (rev == NULL || strcmp (rev, rcs->head) == 0)
+    if (rev == NULL || STREQ (rev, rcs->head))
     {
 	int gothead;
 
 	/* We want the head revision.  Try to read it directly.  */
 
 	if (rcs->flags & PARTIAL)
-	    RCS_reparsercsfile (rcs, &fp);
+	    RCS_reparsercsfile (rcs, &fp, &rcsbuf);
 	else
-	{
-	    fp = CVS_FOPEN (rcs->path, FOPEN_BINARY_READ);
-	    if (fp == NULL)
-		error (1, 0, "unable to reopen `%s'", rcs->path);
-	    if (fseek (fp, rcs->delta_pos, SEEK_SET) != 0)
-		error (1, 0, "cannot fseek RCS file");
-	}
+	    rcsbuf_cache_open (rcs, rcs->delta_pos, &fp, &rcsbuf);
 
 	gothead = 0;
-	getrcsrev (fp, &key);
-	while (getrcskey (fp, &key, &value, &len) >= 0)
+	if (! rcsbuf_getrevnum (&rcsbuf, &key))
+	    error (1, 0, "unexpected EOF reading %s", rcs->path);
+	while (rcsbuf_getkey (&rcsbuf, &key, &value))
 	{
-	    if (strcmp (key, "log") == 0)
-	    {
-		log = xmalloc (len);
-		memcpy (log, value, len);
-		loglen = len;
-	    }
-	    if (strcmp (key, "text") == 0)
+	    if (STREQ (key, "log"))
+		log = rcsbuf_valcopy (&rcsbuf, value, 0, &loglen);
+	    else if (STREQ (key, "text"))
 	    {
 		gothead = 1;
 		break;
@@ -3012,20 +3612,23 @@ RCS_checkout (rcs, workfile, rev, nametag, options, sout, pfn, callerdat)
 	    return 1;
 	}
 
+	rcsbuf_valpolish (&rcsbuf, value, 0, &len);
+
 	if (fstat (fileno (fp), &sb) < 0)
 	    error (1, errno, "cannot fstat %s", rcs->path);
 
-	if (fclose (fp) < 0)
-	    error (0, errno, "cannot close %s", rcs->path);
+	rcsbuf_cache (rcs, &rcsbuf);
     }
     else
     {
+	struct rcsbuffer *rcsbufp;
+
 	/* It isn't the head revision of the trunk.  We'll need to
 	   walk through the deltas.  */
 
 	fp = NULL;
 	if (rcs->flags & PARTIAL)
-	    RCS_reparsercsfile (rcs, &fp);
+	    RCS_reparsercsfile (rcs, &fp, &rcsbuf);
 
 	if (fp == NULL)
 	{
@@ -3033,14 +3636,17 @@ RCS_checkout (rcs, workfile, rev, nametag, options, sout, pfn, callerdat)
 	       here too.  Probably should change it thusly....  */
 	    if (stat (rcs->path, &sb) < 0)
 		error (1, errno, "cannot stat %s", rcs->path);
+	    rcsbufp = NULL;
 	}
 	else
 	{
 	    if (fstat (fileno (fp), &sb) < 0)
 		error (1, errno, "cannot fstat %s", rcs->path);
+	    rcsbufp = &rcsbuf;
 	}
 
-	RCS_deltas (rcs, fp, rev, RCS_FETCH, &value, &len, &log, &loglen);
+	RCS_deltas (rcs, fp, rcsbufp, rev, RCS_FETCH, &value, &len,
+		    &log, &loglen);
 	free_value = 1;
     }
 
@@ -3063,7 +3669,7 @@ RCS_checkout (rcs, workfile, rev, nametag, options, sout, pfn, callerdat)
 	    ouroptions = rcs->expand;
 
 	for (cpp = kflags; *cpp != NULL; cpp++)
-	    if (strcmp (*cpp, ouroptions) == 0)
+	    if (STREQ (*cpp, ouroptions))
 		break;
 
 	if (*cpp != NULL)
@@ -3077,17 +3683,186 @@ RCS_checkout (rcs, workfile, rev, nametag, options, sout, pfn, callerdat)
 	}
     }
 
-    if (expand != KFLAG_O && expand != KFLAG_B)
+#ifdef PRESERVE_PERMISSIONS_SUPPORT
+    /* Handle special files and permissions, if that is desired. */
+    if (preserve_perms)
     {
-	Node *p;
-	char *newvalue;
+	RCSVers *vers;
+	Node *info;
+	struct hardlink_info *hlinfo;
 
-	p = findnode (rcs->versions, rev == NULL ? rcs->head : rev);
-	if (p == NULL)
+	vp = findnode (rcs->versions, rev == NULL ? rcs->head : rev);
+	if (vp == NULL)
 	    error (1, 0, "internal error: no revision information for %s",
 		   rev == NULL ? rcs->head : rev);
+	vers = (RCSVers *) vp->data;
+
+	/* First we look for symlinks, which are simplest to handle. */
+	info = findnode (vers->other_delta, "symlink");
+	if (info != NULL)
+	{
+	    char *dest;
+
+	    if (pfn != NULL || (workfile == NULL && sout == RUN_TTY))
+		error (1, 0, "symbolic link %s:%s cannot be piped",
+		       rcs->path, vers->version);
+	    if (workfile == NULL)
+		dest = sout;
+	    else
+		dest = workfile;
+
+	    /* Remove `dest', just in case.  It's okay to get ENOENT here,
+	       since we just want the file not to be there.  (TODO: decide
+	       whether it should be considered an error for `dest' to exist
+	       at this point.  If so, the unlink call should be removed and
+	       `symlink' should signal the error. -twp) */
+	    if (unlink (dest) < 0 && existence_error (errno))
+		error (1, errno, "cannot remove %s", dest);
+	    if (symlink (info->data, dest) < 0)
+		error (1, errno, "cannot create symbolic link from %s to %s",
+		       dest, info->data);
+	    if (free_value)
+		free (value);
+	    if (free_rev)
+		free (rev);
+	    return 0;
+	}
+
+	/* Next, we look at this file's hardlinks field, and see whether
+	   it is linked to any other file that has been checked out.
+	   If so, we don't do anything else -- just link it to that file.
 
-	expand_keywords (rcs, (RCSVers *) p->data, nametag, log, loglen,
+	   If we are checking out a file to a pipe or temporary storage,
+	   none of this should matter.  Hence the `workfile != NULL'
+	   wrapper around the whole thing. -twp */
+
+	if (workfile != NULL)
+	{
+	    info = findnode (vers->other_delta, "hardlinks");
+	    if (info != NULL)
+	    {
+		char *links = xstrdup (info->data);
+		char *working_dir = xgetwd();
+		char *p, *file = NULL;
+		Node *n, *uptodate_link;
+
+		/* For each file in the hardlinks field, check to see
+		   if it exists, and if so, if it has been checked out
+		   this iteration. */
+		uptodate_link = NULL;
+		for (p = strtok (links, " ");
+		     p != NULL && uptodate_link == NULL;
+		     p = strtok (NULL, " "))
+		{
+		    file = (char *)
+			xmalloc (sizeof(char) *
+				 (strlen(working_dir) + strlen(p) + 2));
+		    sprintf (file, "%s/%s", working_dir, p);
+		    n = lookup_file_by_inode (file);
+		    if (n == NULL)
+		    {
+			if (strcmp (p, workfile) != 0)
+			{
+			    /* One of the files that WORKFILE should be
+			       linked to is not even in the working directory.
+			       The user should probably be warned. */
+			    error (0, 0,
+		"warning: %s should be hardlinked to %s, but is missing",
+				   p, workfile);
+			}
+			free (file);
+			continue;
+		    }
+
+		    /* hlinfo may be NULL if, for instance, a file is being
+		       removed. */
+		    hlinfo = (struct hardlink_info *) n->data;
+		    if (hlinfo && hlinfo->checked_out)
+			uptodate_link = n;
+		    free (file);
+		}
+		free (links);
+		free (working_dir);
+
+		/* If we've found a file that `workfile' is supposed to be
+		   linked to, and it has been checked out since CVS was
+		   invoked, then simply link workfile to that file.
+
+		   If one of these conditions is not met, then we're
+		   checking out workfile to a temp file or stdout, or
+		   workfile is the first one in its hardlink group to be
+		   checked out.  Either way we must continue with a full
+		   checkout. */
+
+		if (uptodate_link != NULL)
+		{
+		    if (link (uptodate_link->key, workfile) < 0)
+			error (1, errno, "cannot link %s to %s",
+			       workfile, uptodate_link->key);
+		    hlinfo->checked_out = 1;	/* probably unnecessary */
+		    if (free_value)
+			free (value);
+		    if (free_rev)
+			free (rev);
+		    return 0;
+		}
+	    }
+	}
+
+	info = findnode (vers->other_delta, "owner");
+	if (info != NULL)
+	{
+	    change_rcs_owner = 1;
+	    rcs_owner = (uid_t) strtoul (info->data, NULL, 10);
+	}
+	info = findnode (vers->other_delta, "group");
+	if (info != NULL)
+	{
+	    change_rcs_group = 1;
+	    rcs_group = (gid_t) strtoul (info->data, NULL, 10);
+	}
+	info = findnode (vers->other_delta, "permissions");
+	if (info != NULL)
+	{
+	    change_rcs_mode = 1;
+	    rcs_mode = (mode_t) strtoul (info->data, NULL, 8);
+	}
+	info = findnode (vers->other_delta, "special");
+	if (info != NULL)
+	{
+	    /* If the size of `devtype' changes, fix the sscanf call also */
+	    char devtype[16];
+
+	    if (sscanf (info->data, "%16s %lu",
+			devtype, &devnum_long) < 2)
+		error (1, 0, "%s:%s has bad `special' newphrase %s",
+		       workfile, vers->version, info->data);
+	    devnum = devnum_long;
+	    if (strcmp (devtype, "character") == 0)
+		special_file = S_IFCHR;
+	    else if (strcmp (devtype, "block") == 0)
+		special_file = S_IFBLK;
+	    else
+		error (0, 0, "%s is a special file of unsupported type `%s'",
+		       workfile, info->data);
+	}
+    }
+#endif
+
+    if (expand != KFLAG_O && expand != KFLAG_B)
+    {
+	char *newvalue;
+
+	/* Don't fetch the delta node again if we already have it. */
+	if (vp == NULL)
+	{
+	    vp = findnode (rcs->versions, rev == NULL ? rcs->head : rev);
+	    if (vp == NULL)
+		error (1, 0, "internal error: no revision information for %s",
+		       rev == NULL ? rcs->head : rev);
+	}
+
+	expand_keywords (rcs, (RCSVers *) vp->data, nametag, log, loglen,
 			 expand, value, len, &newvalue, &len);
 
 	if (newvalue != value)
@@ -3107,19 +3882,55 @@ RCS_checkout (rcs, workfile, rev, nametag, options, sout, pfn, callerdat)
 
     if (pfn != NULL)
     {
+#ifdef PRESERVE_PERMISSIONS_SUPPORT
+	if (special_file)
+	    error (1, 0, "special file %s cannot be piped to anything",
+		   rcs->path);
+#endif
 	/* The PFN interface is very simple to implement right now, as
            we always have the entire file in memory.  */
 	if (len != 0)
 	    pfn (callerdat, value, len);
     }
+#ifdef PRESERVE_PERMISSIONS_SUPPORT
+    else if (special_file)
+    {
+	char *dest;
+
+	/* Can send either to WORKFILE or to SOUT, as long as SOUT is
+	   not RUN_TTY. */
+	dest = workfile;
+	if (dest == NULL)
+	{
+	    if (sout == RUN_TTY)
+		error (1, 0, "special file %s cannot be written to stdout",
+		       rcs->path);
+	    dest = sout;
+	}
+
+	/* Unlink `dest', just in case.  It's okay if this provokes a
+	   ENOENT error. */
+	if (unlink (dest) < 0 && existence_error (errno))
+	    error (1, errno, "cannot remove %s", dest);
+	if (mknod (dest, special_file, devnum) < 0)
+	    error (1, errno, "could not create special file %s",
+		   dest);
+    }
+#endif
     else
     {
+	/* Not a special file: write to WORKFILE or SOUT. */
 	if (workfile == NULL)
 	{
 	    if (sout == RUN_TTY)
 		ofp = stdout;
 	    else
 	    {
+		/* Symbolic links should be removed before replacement, so that
+		   `fopen' doesn't follow the link and open the wrong file. */
+		if (islink (sout))
+		    if (unlink_file (sout) < 0)
+			error (1, errno, "cannot remove %s", sout);
 		ofp = CVS_FOPEN (sout, expand == KFLAG_B ? "wb" : "w");
 		if (ofp == NULL)
 		    error (1, errno, "cannot open %s", sout);
@@ -3127,6 +3938,11 @@ RCS_checkout (rcs, workfile, rev, nametag, options, sout, pfn, callerdat)
 	}
 	else
 	{
+	    /* Output is supposed to go to WORKFILE, so we should open that
+	       file.  Symbolic links should be removed first (see above). */
+	    if (islink (workfile))
+		if (unlink_file (workfile) < 0)
+		    error (1, errno, "cannot remove %s", workfile);
 	    ofp = CVS_FOPEN (workfile, expand == KFLAG_B ? "wb" : "w");
 	    if (ofp == NULL)
 		error (1, errno, "cannot open %s", workfile);
@@ -3171,22 +3987,56 @@ RCS_checkout (rcs, workfile, rev, nametag, options, sout, pfn, callerdat)
 		    nstep = nleft;
 	    }
 	}
+    }
 
-	if (workfile != NULL)
+    if (workfile != NULL)
+    {
+	int ret;
+
+#ifdef PRESERVE_PERMISSIONS_SUPPORT
+	if (!special_file && fclose (ofp) < 0)
+	    error (1, errno, "cannot close %s", workfile);
+
+	if (change_rcs_owner || change_rcs_group)
 	{
-	    if (fclose (ofp) < 0)
-		error (1, errno, "cannot close %s", workfile);
-	    if (chmod (workfile,
-		       sb.st_mode & ~(S_IWRITE | S_IWGRP | S_IWOTH)) < 0)
-		error (0, errno, "cannot change mode of file %s",
+	    if (chown (workfile, rcs_owner, rcs_group) < 0)
+		error (0, errno, "could not change file ownership on %s",
 		       workfile);
 	}
-	else if (sout != RUN_TTY)
+
+	ret = chmod (workfile,
+		     change_rcs_mode
+		     ? rcs_mode
+		     : sb.st_mode & ~(S_IWRITE | S_IWGRP | S_IWOTH));
+#else
+	if (fclose (ofp) < 0)
+	    error (1, errno, "cannot close %s", workfile);
+
+	ret = chmod (workfile,
+		     sb.st_mode & ~(S_IWRITE | S_IWGRP | S_IWOTH));
+#endif
+	if (ret < 0)
 	{
-	    if (fclose (ofp) < 0)
-		error (1, errno, "cannot close %s", sout);
+	    error (0, errno, "cannot change mode of file %s",
+		   workfile);
 	}
     }
+    else if (sout != RUN_TTY)
+    {
+	if (
+#ifdef PRESERVE_PERMISSIONS_SUPPORT
+	    !special_file &&
+#endif
+	    fclose (ofp) < 0)
+	    error (1, errno, "cannot close %s", sout);
+    }
+
+#ifdef PRESERVE_PERMISSIONS_SUPPORT
+    /* If we are in the business of preserving hardlinks, then
+       mark this file as having been checked out. */
+    if (preserve_perms && workfile != NULL)
+	update_hardlink_info (workfile);
+#endif
 
     if (free_value)
 	free (value);
@@ -3235,7 +4085,7 @@ RCS_findlock_or_tip (rcs)
     lock = NULL;
     for (p = locklist->list->next; p != locklist->list; p = p->next)
     {
-	if (strcmp (p->data, user) == 0)
+	if (STREQ (p->data, user))
 	{
 	    if (lock != NULL)
 	    {
@@ -3341,8 +4191,11 @@ compare_truncated_revnums (r, s)
    FIXME: isn't the max rev always the last one?
    If so, we don't even need a loop.  */
 
+static char *max_rev PROTO ((const RCSVers *));
+
 static char *
-max_rev (const RCSVers *branchnode)
+max_rev (branchnode)
+    const RCSVers *branchnode;
 {
     Node *head;
     Node *bp;
@@ -3477,22 +4330,27 @@ RCS_addbranch (rcs, branch)
     return newrevnum;
 }
 
-/* Check in to RCSFILE with revision REV (which must be greater than the
-   largest revision) and message MESSAGE (which is checked for legality).
-   If FLAGS & RCS_FLAGS_DEAD, check in a dead revision.  If FLAGS &
-   RCS_FLAGS_QUIET, tell ci to be quiet.  If FLAGS & RCS_FLAGS_MODTIME,
-   use the working file's modification time for the checkin time.
-   WORKFILE is the working file to check in from, or NULL to use the usual
-   RCS rules for deriving it from the RCSFILE.
+/* Check in to RCSFILE with revision REV (which must be greater than
+   the largest revision) and message MESSAGE (which is checked for
+   legality).  If FLAGS & RCS_FLAGS_DEAD, check in a dead revision.
+   If FLAGS & RCS_FLAGS_QUIET, tell ci to be quiet.  If FLAGS &
+   RCS_FLAGS_MODTIME, use the working file's modification time for the
+   checkin time.  WORKFILE is the working file to check in from, or
+   NULL to use the usual RCS rules for deriving it from the RCSFILE.
+   If FLAGS & RCS_FLAGS_KEEPFILE, don't unlink the working file;
+   unlinking the working file is standard RCS behavior, but is rarely
+   appropriate for CVS.
+
+   This function should almost exactly mimic the behavior of `rcs ci'.  The
+   principal point of difference is the support here for preserving file
+   ownership and permissions in the delta nodes.  This is not a clean
+   solution -- precisely because it diverges from RCS's behavior -- but
+   it doesn't seem feasible to do this anywhere else in the code. [-twp]
    
    Return value is -1 for error (and errno is set to indicate the
    error), positive for error (and an error message has been printed),
    or zero for success.  */
 
-/* TODO: RCS_checkin always unlinks the working file after checkin --
-   then RCS_checkout checks it out again.  The logic should probably
-   be reversed here. */
-
 int
 RCS_checkin (rcs, workfile, message, rev, flags)
     RCSNode *rcs;
@@ -3515,7 +4373,7 @@ RCS_checkin (rcs, workfile, message, rev, flags)
     commitpt = NULL;
 
     if (rcs->flags & PARTIAL)
-	RCS_reparsercsfile (rcs, NULL);
+	RCS_reparsercsfile (rcs, (FILE **) NULL, (struct rcsbuffer *) NULL);
 
     /* Get basename of working file.  Is there a library function to
        do this?  I couldn't find one. -twp */
@@ -3569,6 +4427,92 @@ RCS_checkin (rcs, workfile, message, rev, flags)
     else
 	delta->state = xstrdup ("Exp");
 
+#ifdef PRESERVE_PERMISSIONS_SUPPORT
+    /* If permissions should be preserved on this project, then
+       save the permission info. */
+    if (preserve_perms)
+    {
+	Node *np;
+	struct stat sb;
+	char buf[64];	/* static buffer should be safe: see usage. -twp */
+	char *fullpath;
+
+	delta->other_delta = getlist();
+
+	if (CVS_LSTAT (workfile, &sb) < 0)
+	    error (1, 1, "cannot lstat %s", workfile);
+
+	if (S_ISLNK (sb.st_mode))
+	{
+	    np = getnode();
+	    np->key = xstrdup ("symlink");
+	    np->data = xreadlink (workfile);
+	    addnode (delta->other_delta, np);
+	}
+	else
+	{
+	    (void) sprintf (buf, "%u", sb.st_uid);
+	    np = getnode();
+	    np->key = xstrdup ("owner");
+	    np->data = xstrdup (buf);
+	    addnode (delta->other_delta, np);
+
+	    (void) sprintf (buf, "%u", sb.st_gid);
+	    np = getnode();
+	    np->key = xstrdup ("group");
+	    np->data = xstrdup (buf);
+	    addnode (delta->other_delta, np);
+	    
+	    (void) sprintf (buf, "%o", sb.st_mode & 07777);
+	    np = getnode();
+	    np->key = xstrdup ("permissions");
+	    np->data = xstrdup (buf);
+	    addnode (delta->other_delta, np);
+
+	    /* Save device number. */
+	    switch (sb.st_mode & S_IFMT)
+	    {
+		case S_IFREG: break;
+		case S_IFCHR:
+		case S_IFBLK:
+		    np = getnode();
+		    np->key = xstrdup ("special");
+		    sprintf (buf, "%s %lu",
+			     ((sb.st_mode & S_IFMT) == S_IFCHR
+			      ? "character" : "block"),
+			     (unsigned long) sb.st_rdev);
+		    np->data = xstrdup (buf);
+		    addnode (delta->other_delta, np);
+		    break;
+
+		default:
+		    error (0, 0, "special file %s has unknown type", workfile);
+	    }
+
+	    /* Save hardlinks. */
+	    fullpath = xgetwd();
+	    fullpath = xrealloc (fullpath,
+				 strlen(fullpath) + strlen(workfile) + 2);
+	    sprintf (fullpath + strlen(fullpath), "/%s", workfile);
+
+	    np = lookup_file_by_inode (fullpath);
+	    if (np == NULL)
+	    {
+		error (1, 0, "lost information on %s's linkage", workfile);
+	    }
+	    else
+	    {
+		struct hardlink_info *hlinfo;
+		hlinfo = (struct hardlink_info *) np->data;
+		np = getnode();
+		np->key = xstrdup ("hardlinks");
+		np->data = xstrdup (hlinfo->links);
+		(void) addnode (delta->other_delta, np);
+	    }
+	}
+    }
+#endif
+
     /* Create a new deltatext node. */
     dtext = (Deltatext *) xmalloc (sizeof (Deltatext));
     memset (dtext, 0, sizeof (Deltatext));
@@ -3607,7 +4551,9 @@ RCS_checkin (rcs, workfile, message, rev, flags)
 
 	dtext->version = xstrdup (newrev);
 	bufsize = 0;
-	get_file(workfile, workfile, "r", &dtext->text, &bufsize, &dtext->len);
+	get_file (workfile, workfile,
+		  rcs->expand != NULL && STREQ (rcs->expand, "b") ? "rb" : "r",
+		  &dtext->text, &bufsize, &dtext->len);
 
 	if (!checkin_quiet)
 	{
@@ -3616,6 +4562,9 @@ RCS_checkin (rcs, workfile, message, rev, flags)
 	    cvs_output ("\n", 1);
 	}
 
+	/* We are probably about to invalidate any cached file.  */
+	rcsbuf_cache_close ();
+
 	fout = rcs_internal_lockfile (rcs->path);
 	RCS_putadmin (rcs, fout);
 	RCS_putdtree (rcs, rcs->head, fout);
@@ -3627,12 +4576,12 @@ RCS_checkin (rcs, workfile, message, rev, flags)
 	rcs_internal_unlockfile (fout, rcs->path);
 	freedeltatext (dtext);
 
-	/* Removing the file here is an RCS user-visible behavior which
-	   we almost surely do not need in the CVS case.  In fact, getting
-	   rid of it should clean up link_file and friends in import.c.  */
-	if (unlink_file (workfile) < 0)
-	    /* FIXME-update-dir: message does not include update_dir.  */
-	    error (0, errno, "cannot remove %s", workfile);
+	if ((flags & RCS_FLAGS_KEEPFILE) == 0)
+	{
+	    if (unlink_file (workfile) < 0)
+		/* FIXME-update-dir: message does not include update_dir.  */
+		error (0, errno, "cannot remove %s", workfile);
+	}
 
 	if (!checkin_quiet)
 	    cvs_output ("done\n", 5);
@@ -3672,7 +4621,7 @@ RCS_checkin (rcs, workfile, message, rev, flags)
 	    goto checkin_done;
 	}
 	else if (commitpt->next == NULL
-		 || strcmp (commitpt->version, rcs->head) == 0)
+		 || STREQ (commitpt->version, rcs->head))
 	    delta->version = increment_revnum (commitpt->version);
 	else
 	    delta->version = RCS_addbranch (rcs, commitpt->version);
@@ -3776,7 +4725,7 @@ RCS_checkin (rcs, workfile, message, rev, flags)
     nodep = findnode (RCS_getlocks (rcs), commitpt->version);
     if (nodep != NULL)
     {
-	if (strcmp (nodep->data, delta->author) != 0)
+	if (! STREQ (nodep->data, delta->author))
 	{
 	    error (0, 0, "%s: revision %s locked by %s",
 		   rcs->path,
@@ -3798,13 +4747,13 @@ RCS_checkin (rcs, workfile, message, rev, flags)
     tmpfile = cvs_temp_name();
     status = RCS_checkout (rcs, NULL, commitpt->version, NULL,
 			   ((rcs->expand != NULL
-			     && strcmp (rcs->expand, "b") == 0)
+			     && STREQ (rcs->expand, "b"))
 			    ? "-kb"
 			    : "-ko"),
 			   tmpfile,
 			   (RCSCHECKOUTPROC)0, NULL);
     if (status != 0)
-	error (1, status < 0 ? errno : 0,
+	error (1, 0,
 	       "could not check out revision %s of `%s'",
 	       commitpt->version, rcs->path);
 
@@ -3815,18 +4764,18 @@ RCS_checkin (rcs, workfile, message, rev, flags)
 
     /* Diff options should include --binary if the RCS file has -kb set
        in its `expand' field. */
-    diffopts = (rcs->expand != NULL && strcmp (rcs->expand, "b") == 0
+    diffopts = (rcs->expand != NULL && STREQ (rcs->expand, "b")
 		? "-a -n --binary"
 		: "-a -n");
 
-    if (strcmp (commitpt->version, rcs->head) == 0 &&
+    if (STREQ (commitpt->version, rcs->head) &&
 	numdots (delta->version) == 1)
     {
 	/* If this revision is being inserted on the trunk, the change text
 	   for the new delta should be the contents of the working file ... */
 	bufsize = 0;
 	get_file (workfile, workfile,
-		  rcs->expand != NULL && strcmp (rcs->expand, "b") == 0 ? "rb" : "r",
+		  rcs->expand != NULL && STREQ (rcs->expand, "b") ? "rb" : "r",
 		  &dtext->text, &bufsize, &dtext->len);
 
 	/* ... and the change text for the old delta should be a diff. */
@@ -3862,7 +4811,7 @@ RCS_checkin (rcs, workfile, message, rev, flags)
 	   This should cause no harm, but doesn't strike me as
 	   immensely clean.  */
 	get_file (changefile, changefile,
-		  rcs->expand != NULL && strcmp (rcs->expand, "b") == 0 ? "rb" : "r",
+		  rcs->expand != NULL && STREQ (rcs->expand, "b") ? "rb" : "r",
 		  &commitpt->text->text, &bufsize, &commitpt->text->len);
 
 	/* If COMMITPT->TEXT->TEXT is NULL, it means that CHANGEFILE
@@ -3899,7 +4848,7 @@ RCS_checkin (rcs, workfile, message, rev, flags)
 	/* See the comment above, at the other get_file invocation,
 	   regarding binary vs. text.  */
 	get_file (changefile, changefile, 
-		  rcs->expand != NULL && strcmp (rcs->expand, "b") == 0 ? "rb" : "r",
+		  rcs->expand != NULL && STREQ (rcs->expand, "b") ? "rb" : "r",
 		  &dtext->text, &bufsize,
 		  &dtext->len);
 	if (dtext->text == NULL)
@@ -3923,7 +4872,7 @@ RCS_checkin (rcs, workfile, message, rev, flags)
 
     if (numdots (commitpt->version) == numdots (delta->version))
     {
-	if (strcmp (commitpt->version, rcs->head) == 0)
+	if (STREQ (commitpt->version, rcs->head))
 	{
 	    delta->next = rcs->head;
 	    rcs->head = xstrdup (delta->version);
@@ -3953,12 +4902,12 @@ RCS_checkin (rcs, workfile, message, rev, flags)
 
     RCS_rewrite (rcs, dtext, commitpt->version);
 
-    /* Removing the file here is an RCS user-visible behavior which
-       we almost surely do not need in the CVS case.  In fact, getting
-       rid of it should clean up link_file and friends in import.c.  */
-    if (unlink_file (workfile) < 0)
-	/* FIXME-update-dir: message does not include update_dir.  */
-	error (1, errno, "cannot remove %s", workfile);
+    if ((flags & RCS_FLAGS_KEEPFILE) == 0)
+    {
+	if (unlink_file (workfile) < 0)
+	    /* FIXME-update-dir: message does not include update_dir.  */
+	    error (1, errno, "cannot remove %s", workfile);
+    }
     if (unlink_file (tmpfile) < 0)
 	error (0, errno, "cannot remove %s", tmpfile);
     if (unlink_file (changefile) < 0)
@@ -4011,42 +4960,70 @@ RCS_cmp_file (rcs, rev, options, filename)
     int retcode;
 
     if (options != NULL && options[0] != '\0')
-	binary = (strcmp (options, "-kb") == 0);
+	binary = STREQ (options, "-kb");
     else
     {
 	char *expand;
 
 	expand = RCS_getexpand (rcs);
-	if (expand != NULL && strcmp (expand, "b") == 0)
+	if (expand != NULL && STREQ (expand, "b"))
 	    binary = 1;
 	else
 	    binary = 0;
     }
 
-    fp = CVS_FOPEN (filename, binary ? FOPEN_BINARY_READ : "r");
-
-    data.filename = filename;
-    data.fp = fp;
-    data.different = 0;
-
-    retcode = RCS_checkout (rcs, (char *) NULL, rev, (char *) NULL,
-			    options, RUN_TTY, cmp_file_buffer,
-			    (void *) &data);
+#ifdef PRESERVE_PERMISSIONS_SUPPORT
+    /* If CVS is to deal properly with special files (when
+       PreservePermissions is on), the best way is to check out the
+       revision to a temporary file and call `xcmp' on the two disk
+       files.  xcmp needs to handle non-regular files properly anyway,
+       so calling it simplifies RCS_cmp_file.  We *could* just yank
+       the delta node out of the version tree and look for device
+       numbers, but writing to disk and calling xcmp is a better
+       abstraction (therefore probably more robust). -twp */
 
-    /* If we have not yet found a difference, make sure that we are at
-       the end of the file.  */
-    if (! data.different)
+    if (preserve_perms)
     {
-	if (getc (fp) != EOF)
-	    data.different = 1;
-    }
+	char *tmp;
 
-    fclose (fp);
+	tmp = cvs_temp_name();
+	retcode = RCS_checkout(rcs, NULL, rev, NULL, options, tmp, NULL, NULL);
+	if (retcode != 0)
+	    return 1;
 
-    if (retcode != 0)
-	return 1;
+	retcode = xcmp (tmp, filename);
+	if (CVS_UNLINK (tmp) < 0)
+	    error (0, errno, "cannot remove %s", tmp);
+	return retcode;
+    }
+    else
+#endif
+    {
+        fp = CVS_FOPEN (filename, binary ? FOPEN_BINARY_READ : "r");
+	
+        data.filename = filename;
+        data.fp = fp;
+        data.different = 0;
+	
+        retcode = RCS_checkout (rcs, (char *) NULL, rev, (char *) NULL,
+				options, RUN_TTY, cmp_file_buffer,
+				(void *) &data);
+
+        /* If we have not yet found a difference, make sure that we are at
+           the end of the file.  */
+        if (! data.different)
+        {
+	    if (getc (fp) != EOF)
+		data.different = 1;
+        }
+	
+        fclose (fp);
 
-    return data.different;
+	if (retcode != 0)
+	    return 1;
+	
+        return data.different;
+    }
 }
 
 /* This is a subroutine of RCS_cmp_file.  It is passed to
@@ -4114,12 +5091,12 @@ RCS_settag (rcs, tag, rev)
     Node *node;
 
     if (rcs->flags & PARTIAL)
-	RCS_reparsercsfile (rcs, NULL);
+	RCS_reparsercsfile (rcs, (FILE **) NULL, (struct rcsbuffer *) NULL);
 
     /* FIXME: This check should be moved to RCS_check_tag.  There is no
        reason for it to be here.  */
-    if (strcmp (tag, TAG_BASE) == 0
-	|| strcmp (tag, TAG_HEAD) == 0)
+    if (STREQ (tag, TAG_BASE)
+	|| STREQ (tag, TAG_HEAD))
     {
 	/* Print the name of the tag might be considered redundant
 	   with the caller, which also prints it.  Perhaps this helps
@@ -4173,7 +5150,7 @@ RCS_deltag (rcs, tag)
     List *symbols;
     Node *node;
     if (rcs->flags & PARTIAL)
-	RCS_reparsercsfile (rcs, NULL);
+	RCS_reparsercsfile (rcs, (FILE **) NULL, (struct rcsbuffer *) NULL);
 
     symbols = RCS_symbols (rcs);
     if (symbols == NULL)
@@ -4196,11 +5173,14 @@ RCS_setbranch (rcs, rev)
      const char *rev;
 {
     if (rcs->flags & PARTIAL)
-	RCS_reparsercsfile (rcs, NULL);
+	RCS_reparsercsfile (rcs, (FILE **) NULL, (struct rcsbuffer *) NULL);
+
+    if (rev && ! *rev)
+	rev = NULL;
 
     if (rev == NULL && rcs->branch == NULL)
 	return 0;
-    if (rev != NULL && rcs->branch != NULL && strcmp (rev, rcs->branch) == 0)
+    if (rev != NULL && rcs->branch != NULL && STREQ (rev, rcs->branch))
 	return 0;
 
     if (rcs->branch != NULL)
@@ -4230,7 +5210,7 @@ RCS_lock (rcs, rev, lock_quiet)
     char *xrev = NULL;
 
     if (rcs->flags & PARTIAL)
-	RCS_reparsercsfile (rcs, NULL);
+	RCS_reparsercsfile (rcs, (FILE **) NULL, (struct rcsbuffer *) NULL);
 
     locks = RCS_getlocks (rcs);
     if (locks == NULL)
@@ -4274,7 +5254,7 @@ RCS_lock (rcs, rev, lock_quiet)
     p = findnode (locks, xrev);
     if (p != NULL)
     {
-	if (strcmp (p->data, user) == 0)
+	if (STREQ (p->data, user))
 	{
 	    /* We already own the lock on this revision, so do nothing. */
 	    free (xrev);
@@ -4326,7 +5306,7 @@ RCS_unlock (rcs, rev, unlock_quiet)
 
     user = getcaller();
     if (rcs->flags & PARTIAL)
-	RCS_reparsercsfile (rcs, NULL);
+	RCS_reparsercsfile (rcs, (FILE **) NULL, (struct rcsbuffer *) NULL);
 
     /* If rev is NULL, unlock the latest revision (first in
        rcs->locks) held by the caller. */
@@ -4353,7 +5333,7 @@ RCS_unlock (rcs, rev, unlock_quiet)
 	lock = NULL;
 	for (p = locks->list->next; p != locks->list; p = p->next)
 	{
-	    if (strcmp (p->data, user) == 0)
+	    if (STREQ (p->data, user))
 	    {
 		if (lock != NULL)
 		{
@@ -4392,7 +5372,7 @@ RCS_unlock (rcs, rev, unlock_quiet)
 	return 0;
     }
 
-    if (strcmp (lock->data, user) != 0)
+    if (! STREQ (lock->data, user))
     {
         /* If the revision is locked by someone else, notify
 	   them.  Note that this shouldn't ever happen if RCS_unlock
@@ -4428,7 +5408,7 @@ RCS_addaccess (rcs, user)
     char *access, *a;
 
     if (rcs->flags & PARTIAL)
-	RCS_reparsercsfile (rcs, NULL);
+	RCS_reparsercsfile (rcs, (FILE **) NULL, (struct rcsbuffer *) NULL);
 
     if (rcs->access == NULL)
 	rcs->access = xstrdup (user);
@@ -4437,7 +5417,7 @@ RCS_addaccess (rcs, user)
 	access = xstrdup (rcs->access);
 	for (a = strtok (access, " "); a != NULL; a = strtok (NULL, " "))
 	{
-	    if (strcmp (a, user) == 0)
+	    if (STREQ (a, user))
 	    {
 		free (access);
 		return;
@@ -4461,7 +5441,7 @@ RCS_delaccess (rcs, user)
     int ulen;
 
     if (rcs->flags & PARTIAL)
-	RCS_reparsercsfile (rcs, NULL);
+	RCS_reparsercsfile (rcs, (FILE **) NULL, (struct rcsbuffer *) NULL);
 
     if (rcs->access == NULL)
 	return;
@@ -4492,7 +5472,7 @@ RCS_getaccess (rcs)
     RCSNode *rcs;
 {
     if (rcs->flags & PARTIAL)
-	RCS_reparsercsfile (rcs, NULL);
+	RCS_reparsercsfile (rcs, (FILE **) NULL, (struct rcsbuffer *) NULL);
 
     return rcs->access;
 }
@@ -4508,7 +5488,7 @@ findtag (node, arg)
 {
     char *rev = (char *)arg;
 
-    if (strcmp (node->data, rev) == 0)
+    if (STREQ (node->data, rev))
 	return 1;
     else
 	return 0;
@@ -4601,7 +5581,7 @@ RCS_delete_revs (rcs, tag1, tag2, inclusive)
     {
 	/* A range consisting of a branch number means the latest revision
 	   on that branch. */
-	if (RCS_isbranch (rcs, rev1) && strcmp (rev1, rev2) == 0)
+	if (RCS_isbranch (rcs, rev1) && STREQ (rev1, rev2))
 	    rev1 = rev2 = RCS_getbranch (rcs, rev1, 0);
 	else
 	{
@@ -4692,12 +5672,12 @@ RCS_delete_revs (rcs, tag1, tag2, inclusive)
 	    *bp = '.';
 	}
     }
-    else if (strcmp (rev1, branchpoint) != 0)
+    else if (! STREQ (rev1, branchpoint))
     {
 	/* Walk deltas from BRANCHPOINT on, looking for REV1. */
 	nodep = findnode (rcs->versions, branchpoint);
 	revp = (RCSVers *) nodep->data;
-	while (revp->next != NULL && strcmp (revp->next, rev1) != 0)
+	while (revp->next != NULL && ! STREQ (revp->next, rev1))
 	{
 	    revp = (RCSVers *) nodep->data;
 	    nodep = findnode (rcs->versions, revp->next);
@@ -4746,7 +5726,7 @@ RCS_delete_revs (rcs, tag1, tag2, inclusive)
 	revp = (RCSVers *) nodep->data;
 
 	if (rev2 != NULL)
-	    found = (strcmp (revp->version, rev2) == 0);
+	    found = STREQ (revp->version, rev2);
 	next = revp->next;
 
 	if ((!found && next != NULL) || rev2_inclusive || rev2 == NULL)
@@ -4843,13 +5823,6 @@ RCS_delete_revs (rcs, tag1, tag2, inclusive)
 	if (status > 0)
 	    goto delrev_done;
 
-	else if (status < 0)
-	{
-	    error (0, errno,
-		   "cannot check out revision %s of %s", after, rcs->path);
-	    goto delrev_done;
-	}
-
 	if (before == NULL)
 	{
 	    /* We are deleting revisions from the head of the tree,
@@ -4877,12 +5850,6 @@ RCS_delete_revs (rcs, tag1, tag2, inclusive)
 				   (RCSCHECKOUTPROC)0, NULL);
 	    if (status > 0)
 		goto delrev_done;
-	    else if (status < 0)
-	    {
-		error (0, errno, "cannot check out revision %s of %s",
-		       before, rcs->path);
-		goto delrev_done;
-	    }
 
 	    outfile = cvs_temp_name();
 	    status = diff_exec (beforefile, afterfile, "-n", outfile);
@@ -4927,7 +5894,7 @@ RCS_delete_revs (rcs, tag1, tag2, inclusive)
        outdated.  (FIXME: would it be safe to use the `dead' field for
        this?  Doubtful.) */
     for (next = rev1;
-	 next != NULL && (after == NULL || strcmp (next, after) != 0);
+	 next != NULL && (after == NULL || ! STREQ (next, after));
 	 next = revp->next)
     {
 	nodep = findnode (rcs->versions, next);
@@ -4952,13 +5919,13 @@ RCS_delete_revs (rcs, tag1, tag2, inclusive)
 	    /* beforep's ->next field already should be equal to after,
 	       which I think is always NULL in this case.  */
 	    ;
-	else if (strcmp (rev1, branchpoint) == 0)
+	else if (STREQ (rev1, branchpoint))
 	{
 	    nodep = findnode (rcs->versions, before);
 	    revp = (RCSVers *) nodep->data;
 	    nodep = revp->branches->list->next;
 	    while (nodep != revp->branches->list &&
-		   strcmp (nodep->key, rev1) != 0)
+		   ! STREQ (nodep->key, rev1))
 		nodep = nodep->next;
 	    assert (nodep != revp->branches->list);
 	    if (after == NULL)
@@ -5478,9 +6445,10 @@ rcs_change_text (name, textbuf, textlen, diffbuf, difflen, retbuf, retlen)
    On error, give a fatal error.  */
 
 static void
-RCS_deltas (rcs, fp, version, op, text, len, log, loglen)
+RCS_deltas (rcs, fp, rcsbuf, version, op, text, len, log, loglen)
     RCSNode *rcs;
     FILE *fp;
+    struct rcsbuffer *rcsbuf;
     char *version;
     enum rcs_delta_op op;
     char **text;
@@ -5488,6 +6456,7 @@ RCS_deltas (rcs, fp, version, op, text, len, log, loglen)
     char **log;
     size_t *loglen;
 {
+    struct rcsbuffer rcsbuf_local;
     char *branchversion;
     char *cpversion;
     char *key;
@@ -5497,7 +6466,6 @@ RCS_deltas (rcs, fp, version, op, text, len, log, loglen)
     RCSVers *prev_vers;
     RCSVers *trunk_vers;
     char *next;
-    int n;
     int ishead, isnext, isversion, onbranch;
     Node *node;
     struct linevector headlines;
@@ -5507,11 +6475,8 @@ RCS_deltas (rcs, fp, version, op, text, len, log, loglen)
 
     if (fp == NULL)
     {
-	fp = CVS_FOPEN (rcs->path, FOPEN_BINARY_READ);
-	if (fp == NULL)
-	    error (1, 0, "unable to reopen `%s'", rcs->path);
-	if (fseek (fp, rcs->delta_pos, SEEK_SET) != 0)
-	    error (1, 0, "cannot fseek RCS file");
+	rcsbuf_cache_open (rcs, rcs->delta_pos, &fp, &rcsbuf_local);
+	rcsbuf = &rcsbuf_local;
     }
 
     ishead = 1;
@@ -5538,9 +6503,10 @@ RCS_deltas (rcs, fp, version, op, text, len, log, loglen)
         *cpversion = '\0';
 
     do {
-	getrcsrev (fp, &key);
+	if (! rcsbuf_getrevnum (rcsbuf, &key))
+	    error (1, 0, "unexpected EOF reading RCS file %s", rcs->path);
 
-	if (next != NULL && strcmp (next, key) != 0)
+	if (next != NULL && ! STREQ (next, key))
 	{
 	    /* This is not the next version we need.  It is a branch
                version which we want to ignore.  */
@@ -5565,27 +6531,30 @@ RCS_deltas (rcs, fp, version, op, text, len, log, loglen)
 	    next = vers->next;
 
 	    /* Compare key and trunkversion now, because key points to
-	       storage controlled by getrcskey.  */
-	    if (strcmp (branchversion, key) == 0)
+	       storage controlled by rcsbuf_getkey.  */
+	    if (STREQ (branchversion, key))
 	        isversion = 1;
 	    else
 	        isversion = 0;
 	}
 
-	while ((n = getrcskey (fp, &key, &value, &vallen)) >= 0)
+	while (1)
 	{
+	    if (! rcsbuf_getkey (rcsbuf, &key, &value))
+		error (1, 0, "%s does not appear to be a valid rcs file",
+		       rcs->path);
+
 	    if (log != NULL
 		&& isversion
-		&& strcmp (key, "log") == 0
-		&& strcmp (branchversion, version) == 0)
+		&& STREQ (key, "log")
+		&& STREQ (branchversion, version))
 	    {
-		*log = xmalloc (vallen);
-		memcpy (*log, value, vallen);
-		*loglen = vallen;
+		*log = rcsbuf_valcopy (rcsbuf, value, 0, loglen);
 	    }
 
-	    if (strcmp (key, "text") == 0)
+	    if (STREQ (key, "text"))
 	    {
+		rcsbuf_valpolish (rcsbuf, value, 0, &vallen);
 		if (ishead)
 		{
 		    if (! linevector_add (&curlines, value, vallen, NULL, 0))
@@ -5604,14 +6573,12 @@ RCS_deltas (rcs, fp, version, op, text, len, log, loglen)
 		break;
 	    }
 	}
-	if (n < 0)
-	    goto l_error;
 
 	if (isversion)
 	{
 	    /* This is either the version we want, or it is the
                branchpoint to the version we want.  */
-	    if (strcmp (branchversion, version) == 0)
+	    if (STREQ (branchversion, version))
 	    {
 	        /* This is the version we want.  */
 		linevector_copy (&headlines, &curlines);
@@ -5691,9 +6658,8 @@ RCS_deltas (rcs, fp, version, op, text, len, log, loglen)
     } while (next != NULL);
 
     free (branchversion);
-    
-    if (fclose (fp) < 0)
-	error (0, errno, "cannot close %s", rcs->path);
+
+    rcsbuf_cache (rcs, rcsbuf);
 
     if (! foundhead)
         error (1, 0, "could not find desired version %s in %s",
@@ -5797,125 +6763,148 @@ RCS_deltas (rcs, fp, version, op, text, len, log, loglen)
     linevector_free (&trunklines);
 
     return;
-
-  l_error:
-    if (ferror (fp))
-	error (1, errno, "cannot read %s", rcs->path);
-    else
-        error (1, 0, "%s does not appear to be a valid rcs file",
-	       rcs->path);
 }
 
+/* Read the information for a single delta from the RCS buffer RCSBUF,
+   whose name is RCSFILE.  *KEYP and *VALP are either NULL, or the
+   first key/value pair to read, as set by rcsbuf_getkey. Return NULL
+   if there are no more deltas.  Store the key/value pair which
+   terminated the read in *KEYP and *VALP.  */
+
 static RCSVers *
-getdelta (fp, rcsfile)
-    FILE *fp;
+getdelta (rcsbuf, rcsfile, keyp, valp)
+    struct rcsbuffer *rcsbuf;
     char *rcsfile;
+    char **keyp;
+    char **valp;
 {
     RCSVers *vnode;
     char *key, *value, *cp;
-    long fpos;
     Node *kv;
 
-    vnode = (RCSVers *) xmalloc (sizeof (RCSVers));
-    memset (vnode, 0, sizeof (RCSVers));
-
-    /* Get revision number. This uses getrcskey because it doesn't
-       croak when encountering unexpected input.  As a result, we have
-       to play unholy games with `key' and `value'. */
-    fpos = ftell (fp);
-    getrcskey (fp, &key, &value, NULL);
+    /* Get revision number if it wasn't passed in. This uses
+       rcsbuf_getkey because it doesn't croak when encountering
+       unexpected input.  As a result, we have to play unholy games
+       with `key' and `value'. */
+    if (*keyp != NULL)
+    {
+	key = *keyp;
+	value = *valp;
+    }
+    else
+    {
+	if (! rcsbuf_getkey (rcsbuf, &key, &value))
+	    error (1, 0, "%s: unexpected EOF", rcsfile);
+    }
 
     /* Make sure that it is a revision number and not a cabbage 
        or something. */
     for (cp = key; (isdigit (*cp) || *cp == '.') && *cp != '\0'; cp++)
 	/* do nothing */ ;
-    if (*cp != '\0' || strncmp (RCSDATE, value, strlen (RCSDATE)) != 0)
+    /* Note that when comparing with RCSDATE, we are not massaging
+       VALUE from the string found in the RCS file.  This is OK since
+       we know exactly what to expect.  */
+    if (*cp != '\0' || strncmp (RCSDATE, value, (sizeof RCSDATE) - 1) != 0)
     {
-	(void) fseek (fp, fpos, SEEK_SET);
-	free (vnode);
+	*keyp = key;
+	*valp = value;
 	return NULL;
     }
+
+    vnode = (RCSVers *) xmalloc (sizeof (RCSVers));
+    memset (vnode, 0, sizeof (RCSVers));
+
     vnode->version = xstrdup (key);
 
-    /* grab the value of the date from value */
-    cp = value + strlen (RCSDATE);/* skip the "date" keyword */
+    /* Grab the value of the date from value.  Note that we are not
+       massaging VALUE from the string found in the RCS file.  */
+    cp = value + (sizeof RCSDATE) - 1;	/* skip the "date" keyword */
     while (whitespace (*cp))		/* take space off front of value */
 	cp++;
 
     vnode->date = xstrdup (cp);
 
     /* Get author field.  */
-    (void) getrcskey (fp, &key, &value, NULL);
-    /* FIXME: should be using errno in case of ferror.  */
-    if (key == NULL || strcmp (key, "author") != 0)
+    if (! rcsbuf_getkey (rcsbuf, &key, &value))
+    {
+	error (1, 0, "unexpected end of file reading %s", rcsfile);
+    }
+    if (! STREQ (key, "author"))
 	error (1, 0, "\
-unable to parse rcs file; `author' not in the expected place");
-    vnode->author = xstrdup (value);
+unable to parse %s; `author' not in the expected place", rcsfile);
+    vnode->author = rcsbuf_valcopy (rcsbuf, value, 0, (size_t *) NULL);
 
     /* Get state field.  */
-    (void) getrcskey (fp, &key, &value, NULL);
-    /* FIXME: should be using errno in case of ferror.  */
-    if (key == NULL || strcmp (key, "state") != 0)
+    if (! rcsbuf_getkey (rcsbuf, &key, &value))
+    {
+	error (1, 0, "unexpected end of file reading %s", rcsfile);
+    }
+    if (! STREQ (key, "state"))
 	error (1, 0, "\
-unable to parse rcs file; `state' not in the expected place");
-    vnode->state = xstrdup (value);
-    if (strcmp (value, "dead") == 0)
+unable to parse %s; `state' not in the expected place", rcsfile);
+    vnode->state = rcsbuf_valcopy (rcsbuf, value, 0, (size_t *) NULL);
+    if (STREQ (value, "dead"))
     {
 	vnode->dead = 1;
     }
 
     /* Note that "branches" and "next" are in fact mandatory, according
-       to doc/RCSFILES.  We perhaps should be giving an error if they
-       are not there.  */
+       to doc/RCSFILES.  */
 
     /* fill in the branch list (if any branches exist) */
-    fpos = ftell (fp);
-    (void) getrcskey (fp, &key, &value, NULL);
-    /* FIXME: should be handling various error conditions better.  */
-    if (key != NULL && strcmp (key, RCSDESC) == 0)
+    if (! rcsbuf_getkey (rcsbuf, &key, &value))
+    {
+	error (1, 0, "unexpected end of file reading %s", rcsfile);
+    }
+    if (STREQ (key, RCSDESC))
     {
-	(void) fseek (fp, fpos, SEEK_SET);
+	*keyp = key;
+	*valp = value;
+	/* Probably could/should be a fatal error.  */
+	error (0, 0, "warning: 'branches' keyword missing from %s", rcsfile);
 	return vnode;
     }
     if (value != (char *) NULL)
     {
 	vnode->branches = getlist ();
+	/* Note that we are not massaging VALUE from the string found
+           in the RCS file.  */
 	do_branches (vnode->branches, value);
     }
 
     /* fill in the next field if there is a next revision */
-    fpos = ftell (fp);
-    (void) getrcskey (fp, &key, &value, NULL);
-    /* FIXME: should be handling various error conditions better.  */
-    if (key != NULL && strcmp (key, RCSDESC) == 0)
+    if (! rcsbuf_getkey (rcsbuf, &key, &value))
     {
-	(void) fseek (fp, fpos, SEEK_SET);
+	error (1, 0, "unexpected end of file reading %s", rcsfile);
+    }
+    if (STREQ (key, RCSDESC))
+    {
+	*keyp = key;
+	*valp = value;
+	/* Probably could/should be a fatal error.  */
+	error (0, 0, "warning: 'next' keyword missing from %s", rcsfile);
 	return vnode;
     }
     if (value != (char *) NULL)
-	vnode->next = xstrdup (value);
+	vnode->next = rcsbuf_valcopy (rcsbuf, value, 0, (size_t *) NULL);
 
     /*
      * XXX - this is where we put the symbolic link stuff???
      * (into newphrases in the deltas).
      */
-    /* FIXME: Does not correctly handle errors, e.g. from stdio.  */
     while (1)
     {
-	fpos = ftell (fp);
-	if (getrcskey (fp, &key, &value, NULL) < 0)
-	    break;
+	if (! rcsbuf_getkey (rcsbuf, &key, &value))
+	    error (1, 0, "unexpected end of file reading %s", rcsfile);
 
-	assert (key != NULL);
-
-	if (strcmp (key, RCSDESC) == 0)
+	if (STREQ (key, RCSDESC))
 	    break;
 
 	/* Enable use of repositories created by certain obsolete
 	   versions of CVS.  This code should remain indefinately;
 	   there is no procedure for converting old repositories, and
 	   checking for it is harmless.  */
-	if (strcmp(key, RCSDEAD) == 0)
+	if (STREQ (key, RCSDEAD))
 	{
 	    vnode->dead = 1;
 	    if (vnode->state != NULL)
@@ -5926,6 +6915,9 @@ unable to parse rcs file; `state' not in the expected place");
 	/* if we have a new revision number, we're done with this delta */
 	for (cp = key; (isdigit (*cp) || *cp == '.') && *cp != '\0'; cp++)
 	    /* do nothing */ ;
+	/* Note that when comparing with RCSDATE, we are not massaging
+	   VALUE from the string found in the RCS file.  This is OK
+	   since we know exactly what to expect.  */
 	if (*cp == '\0' && strncmp (RCSDATE, value, strlen (RCSDATE)) == 0)
 	    break;
 
@@ -5936,7 +6928,7 @@ unable to parse rcs file; `state' not in the expected place");
 	kv = getnode ();
 	kv->type = RCSFIELD;
 	kv->key = xstrdup (key);
-	kv->data = xstrdup (value);
+	kv->data = rcsbuf_valcopy (rcsbuf, value, 1, (size_t *) NULL);
 	if (addnode (vnode->other_delta, kv) != 0)
 	{
 	    /* Complaining about duplicate keys in newphrases seems
@@ -5948,11 +6940,11 @@ unable to parse rcs file; `state' not in the expected place");
 		   key, rcsfile);
 	    freenode (kv);
 	}
-     }
+    }
 
-    /* We got here because we read beyond the end of a delta.  Seek back
-       to the beginning of the erroneous read. */
-    (void) fseek (fp, fpos, SEEK_SET);
+    /* Return the key which caused us to fail back to the caller.  */
+    *keyp = key;
+    *valp = value;
 
     return vnode;
 }
@@ -5973,25 +6965,21 @@ freedeltatext (d)
 }
 
 static Deltatext *
-RCS_getdeltatext (rcs, fp)
+RCS_getdeltatext (rcs, fp, rcsbuf)
     RCSNode *rcs;
     FILE *fp;
+    struct rcsbuffer *rcsbuf;
 {
     char *num;
     char *key, *value;
-    int n;
     Node *p;
     Deltatext *d;
-    size_t textlen;
 
     /* Get the revision number. */
-    n = getrevnum (fp, &num);
-    if (ferror (fp))
-	error (1, errno, "%s: cannot read", rcs->path);
-    if (n == EOF)
+    if (! rcsbuf_getrevnum (rcsbuf, &num))
     {
-	/* If n == EOF and num == NULL, it means we reached EOF
-	   naturally.  That's fine. */
+	/* If num == NULL, it means we reached EOF naturally.  That's
+	   fine. */
 	if (num == NULL)
 	    return NULL;
 	else
@@ -6007,36 +6995,36 @@ RCS_getdeltatext (rcs, fp)
     d->version = xstrdup (num);
 
     /* Get the log message. */
-    if (getrcskey (fp, &key, &value, NULL) < 0)
+    if (! rcsbuf_getkey (rcsbuf, &key, &value))
 	error (1, 0, "%s, delta %s: unexpected EOF", rcs->path, num);
-    if (strcmp (key, "log") != 0)
+    if (! STREQ (key, "log"))
 	error (1, 0, "%s, delta %s: expected `log', got `%s'",
 	       rcs->path, num, key);
-    d->log = xstrdup (value);
+    d->log = rcsbuf_valcopy (rcsbuf, value, 0, (size_t *) NULL);
 
     /* Get random newphrases. */
     d->other = getlist();
-    for (n = getrcskey (fp, &key, &value, &textlen);
-	 n >= 0 && strcmp (key, "text") != 0;
-	 n = getrcskey (fp, &key, &value, &textlen))
+    while (1)
     {
+	if (! rcsbuf_getkey (rcsbuf, &key, &value))
+	    error (1, 0, "%s, delta %s: unexpected EOF", rcs->path, num);
+
+	if (STREQ (key, "text"))
+	    break;
+
 	p = getnode();
 	p->type = RCSFIELD;
 	p->key = xstrdup (key);
-	p->data = xstrdup (value);
+	p->data = rcsbuf_valcopy (rcsbuf, value, 1, (size_t *) NULL);
 	if (addnode (d->other, p) < 0)
 	{
 	    error (0, 0, "warning: %s, delta %s: duplicate field `%s'",
 		   rcs->path, num, key);
 	}
     }
-    if (n < 0)
-	error (1, 0, "%s, delta %s: unexpected EOF", rcs->path, num);
 
     /* Get the change text. We already know that this key is `text'. */
-    d->text = (char *) malloc (textlen + 1);
-    d->len = textlen;
-    memcpy (d->text, value, textlen);
+    d->text = rcsbuf_valcopy (rcsbuf, value, 0, &d->len);
 
     return d;
 }
@@ -6053,11 +7041,23 @@ RCS_getdeltatext (rcs, fp)
    not get corrupted. */
 
 static int
-putsymbol_proc (symnode, fp)
+putsymbol_proc (symnode, fparg)
     Node *symnode;
-    void *fp;
+    void *fparg;
 {
-    return fprintf ((FILE *) fp, "\n\t%s:%s", symnode->key, symnode->data);
+    FILE *fp = (FILE *) fparg;
+
+    /* A fiddly optimization: this code used to just call fprintf, but
+       in an old repository with hundreds of tags this can get called
+       hundreds of thousands of times when doing a cvs tag.  Since
+       tagging is a relatively common operation, and using putc and
+       fputs is just as comprehensible, the change is worthwhile.  */
+    putc ('\n', fp);
+    putc ('\t', fp);
+    fputs (symnode->key, fp);
+    putc (':', fp);
+    fputs (symnode->data, fp);
+    return 0;
 }
 
 static int putlock_proc PROTO ((Node *, void *));
@@ -6109,9 +7109,9 @@ putrcsfield_proc (node, vfp)
 
     /* desc, log and text fields should not be terminated with semicolon;
        all other fields should be. */
-    if (strcmp (node->key, "desc") != 0 &&
-	strcmp (node->key, "log") != 0 &&
-	strcmp (node->key, "text") != 0)
+    if (! STREQ (node->key, "desc") &&
+	! STREQ (node->key, "log") &&
+	! STREQ (node->key, "text"))
     {
 	putc (';', fp);
     }
@@ -6141,7 +7141,15 @@ RCS_putadmin (rcs, fp)
     fputs (";\n", fp);
 
     fputs (RCSSYMBOLS, fp);
-    walklist (RCS_symbols(rcs), putsymbol_proc, (void *) fp);
+    /* If we haven't had to convert the symbols to a list yet, don't
+       force a conversion now; just write out the string.  */
+    if (rcs->symbols == NULL && rcs->symbols_data != NULL)
+    {
+	fputs ("\n\t", fp);
+	fputs (rcs->symbols_data, fp);
+    }
+    else
+	walklist (RCS_symbols (rcs), putsymbol_proc, (void *) fp);
     fputs (";\n", fp);
 
     fputs ("locks", fp);
@@ -6159,7 +7167,7 @@ RCS_putadmin (rcs, fp)
 	expand_at_signs (rcs->comment, (off_t) strlen (rcs->comment), fp);
 	fputs ("@;\n", fp);
     }
-    if (rcs->expand && strcmp (rcs->expand, "kv") != 0)
+    if (rcs->expand && ! STREQ (rcs->expand, "kv"))
 	fprintf (fp, "%s\t@%s@;\n", RCSEXPAND, rcs->expand);
 
     walklist (rcs->other, putrcsfield_proc, (void *) fp);
@@ -6281,40 +7289,68 @@ putdeltatext (fp, d)
    increasing order.) */
 
 static void
-RCS_copydeltas (rcs, fin, fout, newdtext, insertpt)
+RCS_copydeltas (rcs, fin, rcsbufin, fout, newdtext, insertpt)
     RCSNode *rcs;
     FILE *fin;
+    struct rcsbuffer *rcsbufin;
     FILE *fout;
     Deltatext *newdtext;
     char *insertpt;
 {
-    Deltatext *dtext;
+    int actions;
     RCSVers *dadmin;
     Node *np;
     int insertbefore, found;
+    char *bufrest;
+    int nls;
+    size_t buflen;
+    char buf[8192];
+    int got;
+
+    /* Count the number of versions for which we have to do some
+       special operation.  */
+    actions = walklist (rcs->versions, count_delta_actions, (void *) NULL);
 
     /* Make a note of whether NEWDTEXT should be inserted
        before or after its INSERTPT. */
     insertbefore = (newdtext != NULL && numdots (newdtext->version) == 1);
 
-    found = 0;
-    while ((dtext = RCS_getdeltatext (rcs, fin)) != NULL)
+    while (actions != 0 || newdtext != NULL)
     {
-	found = (insertpt != NULL && strcmp (dtext->version, insertpt) == 0);
+	Deltatext *dtext;
+
+	dtext = RCS_getdeltatext (rcs, fin, rcsbufin);
+
+	/* We shouldn't hit EOF here, because that would imply that
+           some action was not taken, or that we could not insert
+           NEWDTEXT.  */
+	if (dtext == NULL)
+	    error (1, 0, "internal error: EOF too early in RCS_copydeltas");
+
+	found = (insertpt != NULL && STREQ (dtext->version, insertpt));
 	if (found && insertbefore)
+	{
 	    putdeltatext (fout, newdtext);
+	    newdtext = NULL;
+	    insertpt = NULL;
+	}
 
 	np = findnode (rcs->versions, dtext->version);
 	dadmin = (RCSVers *) np->data;
 
 	/* If this revision has been outdated, just skip it. */
 	if (dadmin->outdated)
+	{
+	    --actions;
 	    continue;
+	}
 	   
 	/* Update the change text for this delta.  New change text
 	   data may come from cvs admin -m, cvs admin -o, or cvs ci. */
 	if (dadmin->text != NULL)
 	{
+	    if (dadmin->text->log != NULL || dadmin->text->text != NULL)
+		--actions;
 	    if (dadmin->text->log != NULL)
 	    {
 		free (dtext->log);
@@ -6333,9 +7369,92 @@ RCS_copydeltas (rcs, fin, fout, newdtext, insertpt)
 	freedeltatext (dtext);
 
 	if (found && !insertbefore)
+	{
 	    putdeltatext (fout, newdtext);
+	    newdtext = NULL;
+	    insertpt = NULL;
+	}
+    }
+
+    /* Copy the rest of the file directly, without bothering to
+       interpret it.  The caller will handle error checking by calling
+       ferror.
+
+       We just wrote a newline to the file, either in putdeltatext or
+       in the caller.  However, we may not have read the corresponding
+       newline from the file, because rcsbuf_getkey returns as soon as
+       it finds the end of the '@' string for the desc or text key.
+       Therefore, we may read three newlines when we should really
+       only write two, and we check for that case here.  This is not
+       an semantically important issue; we only do it to make our RCS
+       files look traditional.  */
+
+    nls = 3;
+
+    rcsbuf_get_buffered (rcsbufin, &bufrest, &buflen);
+    if (buflen > 0)
+    {
+	if (bufrest[0] != '\n'
+	    || strncmp (bufrest, "\n\n\n", buflen < 3 ? buflen : 3) != 0)
+	{
+	    nls = 0;
+	}
+	else
+	{
+	    if (buflen < 3)
+		nls -= buflen;
+	    else
+	    {
+		++bufrest;
+		--buflen;
+		nls = 0;
+	    }
+	}
+
+	fwrite (bufrest, 1, buflen, fout);
+    }
+
+    while ((got = fread (buf, 1, sizeof buf, fin)) != 0)
+    {
+	if (nls > 0
+	    && got >= nls
+	    && buf[0] == '\n'
+	    && strncmp (buf, "\n\n\n", nls) == 0)
+	{
+	    fwrite (buf + 1, 1, got - 1, fout);
+	}
+	else
+	{
+	    fwrite (buf, 1, got, fout);
+	}
+
+	nls = 0;
+    }
+}
+
+/* A helper procedure for RCS_copydeltas.  This is called via walklist
+   to count the number of RCS revisions for which some special action
+   is required.  */
+
+int
+count_delta_actions (np, ignore)
+    Node *np;
+    void *ignore;
+{
+    RCSVers *dadmin;
+
+    dadmin = (RCSVers *) np->data;
+
+    if (dadmin->outdated)
+	return 1;
+
+    if (dadmin->text != NULL
+	&& (dadmin->text->log != NULL || dadmin->text->text != NULL))
+    {
+	return 1;
     }
-    putc ('\n', fout);
+
+    return 0;
 }
 
 /* RCS_internal_lockfile and RCS_internal_unlockfile perform RCS-style
@@ -6443,6 +7562,12 @@ rcs_internal_unlockfile (fp, rcsfile)
        corrupting the repository. */
 
     if (ferror (fp))
+	/* The only case in which using errno here would be meaningful
+	   is if we happen to have left errno unmolested since the call
+	   which produced the error (e.g. fprintf).  That is pretty
+	   fragile even if it happens to sometimes be true.  The real
+	   solution is to check each call to fprintf rather than waiting
+	   until the end like this.  */
 	error (1, 0, "error writing to lock file %s", lockfile);
     if (fclose (fp) == EOF)
 	error (1, errno, "error closing lock file %s", lockfile);
@@ -6486,6 +7611,7 @@ RCS_rewrite (rcs, newdtext, insertpt)
     char *insertpt;
 {
     FILE *fin, *fout;
+    struct rcsbuffer rcsbufin;
 
     if (noexec)
 	return;
@@ -6497,10 +7623,7 @@ RCS_rewrite (rcs, newdtext, insertpt)
     RCS_putdesc (rcs, fout);
 
     /* Open the original RCS file and seek to the first delta text. */
-    if ((fin = CVS_FOPEN (rcs->path, FOPEN_BINARY_READ)) == NULL) 
-	error (1, errno, "cannot open RCS file `%s' for reading", rcs->path);
-    if (fseek (fin, rcs->delta_pos, SEEK_SET) < 0)
-	error (1, errno, "cannot fseek in RCS file %s", rcs->path);
+    rcsbuf_cache_open (rcs, rcs->delta_pos, &fin, &rcsbufin);
 
     /* Update delta_pos to the current position in the output file.
        Do NOT move these statements: they must be done after fin has
@@ -6510,10 +7633,19 @@ RCS_rewrite (rcs, newdtext, insertpt)
     if (rcs->delta_pos == -1)
 	error (1, errno, "cannot ftell in RCS file %s", rcs->path);
 
-    RCS_copydeltas (rcs, fin, fout, newdtext, insertpt);
+    RCS_copydeltas (rcs, fin, &rcsbufin, fout, newdtext, insertpt);
 
+    /* We don't want to call rcsbuf_cache here, since we're about to
+       delete the file.  */
+    rcsbuf_close (&rcsbufin);
     if (ferror (fin))
-	error (0, errno, "warning: when closing RCS file `%s'", rcs->path);
+	/* The only case in which using errno here would be meaningful
+	   is if we happen to have left errno unmolested since the call
+	   which produced the error (e.g. fread).  That is pretty
+	   fragile even if it happens to sometimes be true.  The real
+	   solution is to make sure that all the code which reads
+	   from fin checks for errors itself (some does, some doesn't).  */
+	error (0, 0, "warning: when closing RCS file `%s'", rcs->path);
     if (fclose (fin) < 0)
 	error (0, errno, "warning: closing RCS file `%s'", rcs->path);
 
@@ -6538,13 +7670,18 @@ annotate_fileproc (callerdat, finfo)
     struct file_info *finfo;
 {
     FILE *fp = NULL;
+    struct rcsbuffer *rcsbufp = NULL;
+    struct rcsbuffer rcsbuf;
     char *version;
 
     if (finfo->rcs == NULL)
         return (1);
 
     if (finfo->rcs->flags & PARTIAL)
-        RCS_reparsercsfile (finfo->rcs, &fp);
+    {
+        RCS_reparsercsfile (finfo->rcs, &fp, &rcsbuf);
+	rcsbufp = &rcsbuf;
+    }
 
     version = RCS_getversion (finfo->rcs, tag, date, force_tag_match,
 			      (int *) NULL);
@@ -6557,7 +7694,7 @@ annotate_fileproc (callerdat, finfo)
     cvs_outerr (finfo->fullname, 0);
     cvs_outerr ("\n***************\n", 0);
 
-    RCS_deltas (finfo->rcs, fp, version, RCS_ANNOTATE, (char **) NULL,
+    RCS_deltas (finfo->rcs, fp, rcsbufp, version, RCS_ANNOTATE, (char **) NULL,
 		(size_t) NULL, (char **) NULL, (size_t *) NULL);
     free (version);
     return 0;
diff --git a/gnu/usr.bin/cvs/src/rcscmds.c b/gnu/usr.bin/cvs/src/rcscmds.c
index 9a237a9be96..3086b57e10c 100644
--- a/gnu/usr.bin/cvs/src/rcscmds.c
+++ b/gnu/usr.bin/cvs/src/rcscmds.c
@@ -487,7 +487,42 @@ diff_exec (file1, file2, options, out)
     char *options;
     char *out;
 {
-    char *args = xmalloc (strlen (options) + 10);
+    char *args;
+
+#ifdef PRESERVE_PERMISSIONS_SUPPORT
+    /* If either file1 or file2 are special files, pretend they are
+       /dev/null.  Reason: suppose a file that represents a block
+       special device in one revision becomes a regular file.  CVS
+       must find the `difference' between these files, but a special
+       file contains no data useful for calculating this metric.  The
+       safe thing to do is to treat the special file as an empty file,
+       thus recording the regular file's full contents.  Doing so will
+       create extremely large deltas at the point of transition
+       between device files and regular files, but this is probably
+       very rare anyway.
+
+       There may be ways around this, but I think they are fraught
+       with danger. -twp */
+
+    if (preserve_perms &&
+	strcmp (file1, DEVNULL) != 0 &&
+	strcmp (file2, DEVNULL) != 0)
+    {
+	struct stat sb1, sb2;
+
+	if (CVS_LSTAT (file1, &sb1) < 0)
+	    error (1, errno, "cannot get file information for %s", file1);
+	if (CVS_LSTAT (file2, &sb2) < 0)
+	    error (1, errno, "cannot get file information for %s", file2);
+
+	if (!S_ISREG (sb1.st_mode) && !S_ISDIR (sb1.st_mode))
+	    file1 = DEVNULL;
+	if (!S_ISREG (sb2.st_mode) && !S_ISDIR (sb2.st_mode))
+	    file2 = DEVNULL;
+    }
+#endif
+
+    args = xmalloc (strlen (options) + 10);
     /* The first word in this string is used only for error reporting. */
     sprintf (args, "diff %s", options);
     call_diff_setup (args);
@@ -507,7 +542,31 @@ diff_execv (file1, file2, label1, label2, options, out)
     char *options;
     char *out;
 {
-    char *args = xmalloc (strlen (options) + 10);
+    char *args;
+
+#ifdef PRESERVE_PERMISSIONS_SUPPORT
+    /* Pretend that special files are /dev/null for purposes of making
+       diffs.  See comments in diff_exec. */
+
+    if (preserve_perms &&
+	strcmp (file1, DEVNULL) != 0 &&
+	strcmp (file2, DEVNULL) != 0)
+    {
+	struct stat sb1, sb2;
+
+	if (CVS_LSTAT (file1, &sb1) < 0)
+	    error (1, errno, "cannot get file information for %s", file1);
+	if (CVS_LSTAT (file2, &sb2) < 0)
+	    error (1, errno, "cannot get file information for %s", file2);
+
+	if (!S_ISREG (sb1.st_mode) && !S_ISDIR (sb1.st_mode))
+	    file1 = DEVNULL;
+	if (!S_ISREG (sb2.st_mode) && !S_ISDIR (sb2.st_mode))
+	    file2 = DEVNULL;
+    }
+#endif
+
+    args = xmalloc (strlen (options) + 10);
     /* The first word in this string is used only for error reporting.  */
     /* I guess we are pretty confident that options starts with a space.  */
     sprintf (args, "diff%s", options);
diff --git a/gnu/usr.bin/cvs/src/server.c b/gnu/usr.bin/cvs/src/server.c
index b512845192f..06e293e0c43 100644
--- a/gnu/usr.bin/cvs/src/server.c
+++ b/gnu/usr.bin/cvs/src/server.c
@@ -1194,7 +1194,7 @@ serve_modified (arg)
     }
 
     {
-	int status = change_mode (arg, mode_text);
+	int status = change_mode (arg, mode_text, 0);
 	free (mode_text);
 	if (status)
 	{
@@ -3355,12 +3355,13 @@ server_modtime (finfo, vers_ts)
 /* See server.h for description.  */
 
 void
-server_updated (finfo, vers, updated, file_info, checksum)
+server_updated (finfo, vers, updated, mode, checksum, filebuf)
     struct file_info *finfo;
     Vers_TS *vers;
     enum server_updated_arg4 updated;
-    struct stat *file_info;
+    mode_t mode;
     unsigned char *checksum;
+    struct buffer *filebuf;
 {
     if (noexec)
     {
@@ -3379,25 +3380,43 @@ server_updated (finfo, vers, updated, file_info, checksum)
     if (entries_line != NULL && scratched_file == NULL)
     {
 	FILE *f;
-	struct stat sb;
 	struct buffer_data *list, *last;
 	unsigned long size;
 	char size_text[80];
 
-	if ( CVS_STAT (finfo->file, &sb) < 0)
+	if (filebuf != NULL)
 	{
-	    if (existence_error (errno))
+	    size = buf_length (filebuf);
+	    if (mode == (mode_t) -1)
+		error (1, 0, "\
+CVS server internal error: no mode in server_updated");
+	}
+	else
+	{
+	    struct stat sb;
+
+	    if ( CVS_STAT (finfo->file, &sb) < 0)
 	    {
-		/*
-		 * If we have a sticky tag for a branch on which the
-		 * file is dead, and cvs update the directory, it gets
-		 * a T_CHECKOUT but no file.  So in this case just
-		 * forget the whole thing.  */
-		free (entries_line);
-		entries_line = NULL;
-		goto done;
+		if (existence_error (errno))
+		{
+		    /* If we have a sticky tag for a branch on which
+		       the file is dead, and cvs update the directory,
+		       it gets a T_CHECKOUT but no file.  So in this
+		       case just forget the whole thing.  */
+		    free (entries_line);
+		    entries_line = NULL;
+		    goto done;
+		}
+		error (1, errno, "reading %s", finfo->fullname);
+	    }
+	    size = sb.st_size;
+	    if (mode == (mode_t) -1)
+	    {
+		/* FIXME: When we check out files the umask of the
+		   server (set in .bashrc if rsh is in use) affects
+		   what mode we send, and it shouldn't.  */
+		mode = sb.st_mode;
 	    }
-	    error (1, errno, "reading %s", finfo->fullname);
 	}
 
 	if (checksum != NULL)
@@ -3466,21 +3485,14 @@ server_updated (finfo, vers, updated, file_info, checksum)
         {
 	    char *mode_string;
 
-	    /* FIXME: When we check out files the umask of the server
-	       (set in .bashrc if rsh is in use) affects what mode we
-	       send, and it shouldn't.  */
-	    if (file_info != NULL)
-	        mode_string = mode_to_string (file_info->st_mode);
-	    else
-	        mode_string = mode_to_string (sb.st_mode);
+	    mode_string = mode_to_string (mode);
 	    buf_output0 (protocol, mode_string);
 	    buf_output0 (protocol, "\n");
 	    free (mode_string);
 	}
 
 	list = last = NULL;
-	size = 0;
-	if (sb.st_size > 0)
+	if (size > 0)
 	{
 	    /* Throughout this section we use binary mode to read the
 	       file we are sending.  The client handles any line ending
@@ -3493,11 +3505,19 @@ server_updated (finfo, vers, updated, file_info, checksum)
 		 * might be computable somehow; using 100 here is just
 		 * a first approximation.
 		 */
-		&& sb.st_size > 100)
+		&& size > 100)
 	    {
 		int status, fd, gzip_status;
 		pid_t gzip_pid;
 
+		/* Callers must avoid passing us a buffer if
+                   file_gzip_level is set.  We could handle this case,
+                   but it's not worth it since this case never arises
+                   with a current client and server.  */
+		if (filebuf != NULL)
+		    error (1, 0, "\
+CVS server internal error: unhandled case in server_updated");
+
 		fd = CVS_OPEN (finfo->file, O_RDONLY | OPEN_BINARY, 0);
 		if (fd < 0)
 		    error (1, errno, "reading %s", finfo->fullname);
@@ -3520,15 +3540,14 @@ server_updated (finfo, vers, updated, file_info, checksum)
 		/* Prepending length with "z" is flag for using gzip here.  */
 		buf_output0 (protocol, "z");
 	    }
-	    else
+	    else if (filebuf == NULL)
 	    {
 		long status;
 
-		size = sb.st_size;
 		f = CVS_FOPEN (finfo->file, "rb");
 		if (f == NULL)
 		    error (1, errno, "reading %s", finfo->fullname);
-		status = buf_read_file (f, sb.st_size, &list, &last);
+		status = buf_read_file (f, size, &list, &last);
 		if (status == -2)
 		    (*protocol->memory_error) (protocol);
 		else if (status != 0)
@@ -3542,7 +3561,13 @@ server_updated (finfo, vers, updated, file_info, checksum)
 	sprintf (size_text, "%lu\n", size);
 	buf_output0 (protocol, size_text);
 
-	buf_append_data (protocol, list, last);
+	if (filebuf == NULL)
+	    buf_append_data (protocol, list, last);
+	else
+	{
+	    buf_append_buffer (protocol, filebuf);
+	    buf_free (filebuf);
+	}
 	/* Note we only send a newline here if the file ended with one.  */
 
 	/*
@@ -3555,6 +3580,7 @@ server_updated (finfo, vers, updated, file_info, checksum)
 	if ((updated == SERVER_UPDATED
 	     || updated == SERVER_PATCHED
 	     || updated == SERVER_RCS_DIFF)
+	    && filebuf != NULL
 	    /* But if we are joining, we'll need the file when we call
 	       join_file.  */
 	    && !joining ())
@@ -5611,7 +5637,7 @@ this client does not support writing binary files to stdout");
 	   I assume that what they are talking about can also be helped
 	   by flushing the stream before changing the mode.  */
 	fflush (stdout);
-	oldmode = _setmode (_fileno (stdout), _O_BINARY);
+	oldmode = _setmode (_fileno (stdout), OPEN_BINARY);
 	if (oldmode < 0)
 	    error (0, errno, "failed to setmode on stdout");
 #endif
@@ -5626,7 +5652,7 @@ this client does not support writing binary files to stdout");
 	}
 #ifdef USE_SETMODE_STDOUT
 	fflush (stdout);
-	if (_setmode (_fileno (stdout), oldmode) != _O_BINARY)
+	if (_setmode (_fileno (stdout), oldmode) != OPEN_BINARY)
 	    error (0, errno, "failed to setmode on stdout");
 #endif
     }
diff --git a/gnu/usr.bin/cvs/src/update.c b/gnu/usr.bin/cvs/src/update.c
index 0563eb346ad..31ee6ca2c75 100644
--- a/gnu/usr.bin/cvs/src/update.c
+++ b/gnu/usr.bin/cvs/src/update.c
@@ -42,9 +42,14 @@
 #include "fileattr.h"
 #include "edit.h"
 #include "getline.h"
+#include "buffer.h"
+#include "hardlink.h"
 
 static int checkout_file PROTO ((struct file_info *finfo, Vers_TS *vers_ts,
-				 int adding));
+				 int adding, int merging, int update_server));
+#ifdef SERVER_SUPPORT
+static void checkout_to_buffer PROTO ((void *, const char *, size_t));
+#endif
 #ifdef SERVER_SUPPORT
 static int patch_file PROTO ((struct file_info *finfo,
 			      Vers_TS *vers_ts, 
@@ -64,6 +69,9 @@ static int update_fileproc PROTO ((void *callerdat, struct file_info *));
 static int update_filesdone_proc PROTO ((void *callerdat, int err,
 					 char *repository, char *update_dir,
 					 List *entries));
+#ifdef PRESERVE_PERMISSIONS_SUPPORT
+static int get_linkinfo_proc PROTO ((void *callerdat, struct file_info *));
+#endif
 static void write_letter PROTO ((struct file_info *finfo, int letter));
 static void join_file PROTO ((struct file_info *finfo, Vers_TS *vers_ts));
 
@@ -79,6 +87,10 @@ static char *date = NULL;
 static int rewrite_tag;
 static int nonbranch;
 
+/* If we set the tag or date for a subdirectory, we use this to undo
+   the setting.  See update_dirent_proc.  */
+static char *tag_update_dir;
+
 static char *join_rev1, *date_rev1;
 static char *join_rev2, *date_rev2;
 static int aflag = 0;
@@ -437,6 +449,32 @@ do_update (argc, argv, xoptions, xtag, xdate, xforce, local, xbuild, xaflag,
     else
 	date_rev2 = (char *) NULL;
 
+#ifdef PRESERVE_PERMISSIONS_SUPPORT
+    if (preserve_perms)
+    {
+	/* We need to do an extra recursion, bleah.  It's to make sure
+	   that we know as much as possible about file linkage. */
+	hardlist = getlist();
+	working_dir = xgetwd();		/* save top-level working dir */
+
+	/* FIXME-twp: the arguments to start_recursion make me dizzy.  This
+	   function call was copied from the update_fileproc call that
+	   follows it; someone should make sure that I did it right. */
+	err = start_recursion (get_linkinfo_proc, (FILESDONEPROC) NULL,
+			       (DIRENTPROC) NULL, (DIRLEAVEPROC) NULL, NULL,
+			       argc, argv, local, which, aflag, 1,
+			       preload_update_dir, 1);
+	if (err)
+	    return (err);
+
+	/* FIXME-twp: at this point we should walk the hardlist
+	   and update the `links' field of each hardlink_info struct
+	   to list the files that are linked on dist.  That would make
+	   it easier & more efficient to compare the disk linkage with
+	   the repository linkage (a simple strcmp). */
+    }
+#endif
+
     /* call the recursion processor */
     err = start_recursion (update_fileproc, update_filesdone_proc,
 			   update_dirent_proc, update_dirleave_proc, NULL,
@@ -456,6 +494,50 @@ do_update (argc, argv, xoptions, xtag, xdate, xforce, local, xbuild, xaflag,
     return (err);
 }
 
+#ifdef PRESERVE_PERMISSIONS_SUPPORT
+/*
+ * The get_linkinfo_proc callback adds each file to the hardlist
+ * (see hardlink.c).
+ */
+
+static int
+get_linkinfo_proc (callerdat, finfo)
+    void *callerdat;
+    struct file_info *finfo;
+{
+    char *fullpath;
+    Node *linkp;
+    struct hardlink_info *hlinfo;
+
+    /* Get the full pathname of the current file. */
+    fullpath = xmalloc (strlen(working_dir) +
+			strlen(finfo->fullname) + 2);
+    sprintf (fullpath, "%s/%s", working_dir, finfo->fullname);
+
+    /* To permit recursing into subdirectories, files
+       are keyed on the full pathname and not on the basename. */
+    linkp = lookup_file_by_inode (fullpath);
+    if (linkp == NULL)
+    {
+	/* The file isn't on disk; we are probably restoring
+	   a file that was removed. */
+	return 0;
+    }
+    
+    /* Create a new, empty hardlink_info node. */
+    hlinfo = (struct hardlink_info *)
+	xmalloc (sizeof (struct hardlink_info));
+
+    hlinfo->status = (Ctype) 0;	/* is this dumb? */
+    hlinfo->checked_out = 0;
+    hlinfo->links = NULL;
+
+    linkp->data = (char *) hlinfo;
+
+    return 0;
+}
+#endif
+
 /*
  * This is the callback proc for update.  It is called for each file in each
  * directory by the recursion code.  The current directory is the local
@@ -526,7 +608,7 @@ update_fileproc (callerdat, finfo)
 #ifdef SERVER_SUPPORT
 	    case T_PATCH:		/* needs patch */
 #endif
-		retval = checkout_file (finfo, vers, 0);
+		retval = checkout_file (finfo, vers, 0, 0, 0);
 		break;
 
 	    default:			/* can't ever happen :-) */
@@ -629,7 +711,8 @@ update_fileproc (callerdat, finfo)
 					    (rcs_diff_patches
 					     ? SERVER_RCS_DIFF
 					     : SERVER_PATCHED),
-					    &file_info, checksum);
+					    file_info.st_mode, checksum,
+					    (struct buffer *) NULL);
 			break;
 		    }
 		}
@@ -639,13 +722,7 @@ update_fileproc (callerdat, finfo)
 		/* Fall through.  */
 #endif
 	    case T_CHECKOUT:		/* needs checkout */
-		retval = checkout_file (finfo, vers, 0);
-#ifdef SERVER_SUPPORT
-		if (server_active && retval == 0)
-		    server_updated (finfo, vers,
-				    SERVER_UPDATED, (struct stat *) NULL,
-				    (unsigned char *) NULL);
-#endif
+		retval = checkout_file (finfo, vers, 0, 0, 1);
 		break;
 	    case T_ADDED:		/* added but not committed */
 		write_letter (finfo, 'A');
@@ -663,8 +740,9 @@ update_fileproc (callerdat, finfo)
 		    if (vers->ts_user == NULL)
 			server_scratch_entry_only ();
 		    server_updated (finfo, vers,
-				    SERVER_UPDATED, (struct stat *) NULL,
-				    (unsigned char *) NULL);
+				    SERVER_UPDATED, (mode_t) -1,
+				    (unsigned char *) NULL,
+				    (struct buffer *) NULL);
 		}
 #endif
 		break;
@@ -806,6 +884,26 @@ update_dirent_proc (callerdat, dir, repository, update_dir, entries)
 	else
 	{
 	    /* otherwise, create the dir and appropriate adm files */
+
+	    /* If no tag or date were specified on the command line,
+               and we're not using -A, we want the subdirectory to use
+               the tag and date, if any, of the current directory.
+               That way, update -d will work correctly when working on
+               a branch.
+
+	       We use TAG_UPDATE_DIR to undo the tag setting in
+	       update_dirleave_proc.  If we did not do this, we would
+	       not correctly handle a working directory with multiple
+	       tags (and maybe we should prohibit such working
+	       directories, but they work now and we shouldn't make
+	       them stop working without more thought).  */
+	    if ((tag == NULL && date == NULL) && ! aflag)
+	    {
+		ParseTag (&tag, &date, &nonbranch);
+		if (tag != NULL || date != NULL)
+		    tag_update_dir = xstrdup (update_dir);
+	    }
+
 	    make_directory (dir);
 	    Create_Admin (dir, update_dir, repository, tag, date,
 			  /* This is a guess.  We will rewrite it later
@@ -897,6 +995,27 @@ update_dirleave_proc (callerdat, dir, err, update_dir, entries)
 {
     FILE *fp;
 
+    /* If we set the tag or date for a new subdirectory in
+       update_dirent_proc, and we're now done with that subdirectory,
+       undo the tag/date setting.  Note that we know that the tag and
+       date were both originally NULL in this case.  */
+    if (tag_update_dir != NULL && strcmp (update_dir, tag_update_dir) == 0)
+    {
+	if (tag != NULL)
+	{
+	    free (tag);
+	    tag = NULL;
+	}
+	if (date != NULL)
+	{
+	    free (date);
+	    date = NULL;
+	}
+	nonbranch = 0;
+	free (tag_update_dir);
+	tag_update_dir = NULL;
+    }
+
     /* run the update_prog if there is one */
     /* FIXME: should be checking for errors from CVS_FOPEN and printing
        them if not existence_error.  */
@@ -1016,7 +1135,7 @@ isemptydir (dir, might_not_exist)
 
 		if (CVS_CHDIR (dir) < 0)
 		    error (1, errno, "cannot change directory to %s", dir);
-		l = Entries_Open (0);
+		l = Entries_Open (0, NULL);
 		files_removed = walklist (l, isremoved, 0);
 		Entries_Close (l);
 
@@ -1063,22 +1182,29 @@ scratch_file (finfo)
  * Check out a file.
  */
 static int
-checkout_file (finfo, vers_ts, adding)
+checkout_file (finfo, vers_ts, adding, merging, update_server)
     struct file_info *finfo;
     Vers_TS *vers_ts;
     int adding;
+    int merging;
+    int update_server;
 {
     char *backup;
     int set_time, retval = 0;
-    int retcode = 0;
     int status;
     int file_is_dead;
+    struct buffer *revbuf;
 
-    /* Solely to suppress a warning from gcc -Wall.  */
     backup = NULL;
+    revbuf = NULL;
 
-    /* don't screw with backup files if we're going to stdout */
-    if (!pipeout)
+    /* Don't screw with backup files if we're going to stdout, or if
+       we are the server.  */
+    if (!pipeout
+#ifdef SERVER_SUPPORT
+	&& ! server_active
+#endif
+	)
     {
 	backup = xmalloc (strlen (finfo->file)
 			  + sizeof (CVSADM)
@@ -1088,6 +1214,7 @@ checkout_file (finfo, vers_ts, adding)
 	if (isfile (finfo->file))
 	    rename_file (finfo->file, backup);
 	else
+	{
 	    /* If -f/-t wrappers are being used to wrap up a directory,
 	       then backup might be a directory instead of just a file.  */
 	    if (unlink_file_dir (backup) < 0)
@@ -1097,6 +1224,9 @@ checkout_file (finfo, vers_ts, adding)
 		    /* FIXME: should include update_dir in message.  */
 		    error (0, errno, "error removing %s", backup);
 	    }
+	    free (backup);
+	    backup = NULL;
+	}
     }
 
     file_is_dead = RCS_isdead (vers_ts->srcfile, vers_ts->vn_rcs);
@@ -1124,22 +1254,64 @@ VERS: ", 0);
 	    }
 	}
 
-	status = RCS_checkout (vers_ts->srcfile,
-			       pipeout ? NULL : finfo->file,
-			       vers_ts->vn_rcs, vers_ts->vn_tag,
-			       vers_ts->options, RUN_TTY,
-			       (RCSCHECKOUTPROC) NULL, (void *) NULL);
+#ifdef SERVER_SUPPORT
+	if (update_server
+	    && server_active
+	    && ! pipeout
+	    && ! file_gzip_level
+	    && ! joining ()
+	    && ! wrap_name_has (finfo->file, WRAP_FROMCVS))
+	{
+	    revbuf = buf_nonio_initialize ((BUFMEMERRPROC) NULL);
+	    status = RCS_checkout (vers_ts->srcfile, (char *) NULL,
+				   vers_ts->vn_rcs, vers_ts->vn_tag,
+				   vers_ts->options, RUN_TTY,
+				   checkout_to_buffer, revbuf);
+	}
+	else
+#endif
+	    status = RCS_checkout (vers_ts->srcfile,
+				   pipeout ? NULL : finfo->file,
+				   vers_ts->vn_rcs, vers_ts->vn_tag,
+				   vers_ts->options, RUN_TTY,
+				   (RCSCHECKOUTPROC) NULL, (void *) NULL);
     }
     if (file_is_dead || status == 0)
     {
+	mode_t mode;
+
+	mode = (mode_t) -1;
+
 	if (!pipeout)
 	{
 	    Vers_TS *xvers_ts;
 
+	    if (revbuf != NULL)
+	    {
+		struct stat sb;
+
+		/* FIXME: We should have RCS_checkout return the mode.  */
+		if (stat (vers_ts->srcfile->path, &sb) < 0)
+		    error (1, errno, "cannot stat %s",
+			   vers_ts->srcfile->path);
+		mode = sb.st_mode &~ (S_IWRITE | S_IWGRP | S_IWOTH);
+	    }
+
 	    if (cvswrite
 		&& !file_is_dead
 		&& !fileattr_get (finfo->file, "_watched"))
-		xchmod (finfo->file, 1);
+	    {
+		if (revbuf == NULL)
+		    xchmod (finfo->file, 1);
+		else
+		{
+		    /* We know that we are the server here, so
+                       although xchmod checks umask, we don't bother.  */
+		    mode |= (((mode & S_IRUSR) ? S_IWUSR : 0)
+			     | ((mode & S_IRGRP) ? S_IWGRP : 0)
+			     | ((mode & S_IROTH) ? S_IWOTH : 0));
+		}
+	    }
 
 	    {
 		/* A newly checked out file is never under the spell
@@ -1171,6 +1343,27 @@ VERS: ", 0);
 	    if (strcmp (xvers_ts->options, "-V4") == 0)
 		xvers_ts->options[0] = '\0';
 
+	    if (revbuf != NULL)
+	    {
+		/* If we stored the file data into a buffer, then we
+                   didn't create a file at all, so xvers_ts->ts_user
+                   is wrong.  The correct value is to have it be the
+                   same as xvers_ts->ts_rcs, meaning that the working
+                   file is unchanged from the RCS file.
+
+		   FIXME: We should tell Version_TS not to waste time
+		   statting the nonexistent file.
+
+		   FIXME: Actually, I don't think the ts_user value
+		   matters at all here.  The only use I know of is
+		   that it is printed in a trace message by
+		   Server_Register.  */
+
+		if (xvers_ts->ts_user != NULL)
+		    free (xvers_ts->ts_user);
+		xvers_ts->ts_user = xstrdup (xvers_ts->ts_rcs);
+	    }
+
 	    (void) time (&last_register_time);
 
 	    if (file_is_dead)
@@ -1179,7 +1372,7 @@ VERS: ", 0);
 		{
 		    error (0, 0,
 			   "warning: %s is not (any longer) pertinent",
-			   finfo->fullname);
+ 			   finfo->fullname);
 		}
 		Scratch_Entry (finfo->entries, finfo->file);
 #ifdef SERVER_SUPPORT
@@ -1226,21 +1419,29 @@ VERS: ", 0);
 		write_letter (finfo, 'U');
 	    }
 	}
+
+#ifdef SERVER_SUPPORT
+	if (update_server && server_active)
+	    server_updated (finfo, vers_ts,
+			    merging ? SERVER_MERGED : SERVER_UPDATED,
+			    mode, (unsigned char *) NULL, revbuf);
+#endif
     }
     else
     {
-	int old_errno = errno;		/* save errno value over the rename */
-
-	if (!pipeout && isfile (backup))
+	if (backup != NULL)
+	{
 	    rename_file (backup, finfo->file);
+	    free (backup);
+	    backup = NULL;
+	}
 
-	error (retcode == -1 ? 1 : 0, retcode == -1 ? old_errno : 0,
-	       "could not check out %s", finfo->fullname);
+	error (0, 0, "could not check out %s", finfo->fullname);
 
-	retval = retcode;
+	retval = status;
     }
 
-    if (!pipeout)
+    if (backup != NULL)
     {
 	/* If -f/-t wrappers are being used to wrap up a directory,
 	   then backup might be a directory instead of just a file.  */
@@ -1259,6 +1460,24 @@ VERS: ", 0);
 
 #ifdef SERVER_SUPPORT
 
+/* This function is used to write data from a file being checked out
+   into a buffer.  */
+
+static void
+checkout_to_buffer (callerdat, data, len)
+     void *callerdat;
+     const char *data;
+     size_t len;
+{
+    struct buffer *buf = (struct buffer *) callerdat;
+
+    buf_output (buf, data, len);
+}
+
+#endif /* SERVER_SUPPORT */
+
+#ifdef SERVER_SUPPORT
+
 /* This structure is used to pass information between patch_file and
    patch_file_write.  */
 
@@ -1335,6 +1554,14 @@ patch_file (finfo, vers_ts, docheckout, file_info, checksum)
 	    free (rev);
     }
 
+    /* If the revision is dead, let checkout_file handle it rather
+       than duplicating the processing here.  */
+    if (RCS_isdead (vers_ts->srcfile, vers_ts->vn_rcs))
+    {
+	*docheckout = 1;
+	return 0;
+    }
+
     backup = xmalloc (strlen (finfo->file)
 		      + sizeof (CVSADM)
 		      + sizeof (CVSPREFIX)
@@ -1649,25 +1876,32 @@ merge_file (finfo, vers)
     xchmod (finfo->file, 1);
 
     if (strcmp (vers->options, "-kb") == 0
-	|| wrap_merge_is_copy (finfo->file))
+	|| wrap_merge_is_copy (finfo->file)
+	|| special_file_mismatch (finfo, NULL, vers->vn_rcs))
     {
-	/* For binary files, a merge is always a conflict.  We give the
+	/* For binary files, a merge is always a conflict.  Same for
+	   files whose permissions or linkage do not match.  We give the
 	   user the two files, and let them resolve it.  It is possible
 	   that we should require a "touch foo" or similar step before
 	   we allow a checkin.  */
-	status = checkout_file (finfo, vers, 0);
+
+	/* TODO: it may not always be necessary to regard a permission
+	   mismatch as a conflict.  The working file and the RCS file
+	   have a common ancestor `A'; if the working file's permissions
+	   match A's, then it's probably safe to overwrite them with the
+	   RCS permissions.  Only if the working file, the RCS file, and
+	   A all disagree should this be considered a conflict.  But more
+	   thought needs to go into this, and in the meantime it is safe
+	   to treat any such mismatch as an automatic conflict. -twp */
+
 #ifdef SERVER_SUPPORT
-	/* Send the new contents of the file before the message.  If we
-	   wanted to be totally correct, we would have the client write
-	   the message only after the file has safely been written.  */
 	if (server_active)
-	{
 	    server_copy_file (finfo->file, finfo->update_dir,
 			      finfo->repository, backup);
-	    server_updated (finfo, vers, SERVER_MERGED,
-			    (struct stat *) NULL, (unsigned char *) NULL);
-	}
 #endif
+
+	status = checkout_file (finfo, vers, 0, 1, 1);
+
 	/* Is there a better term than "nonmergeable file"?  What we
 	   really mean is, not something that CVS cannot or does not
 	   want to merge (there might be an external manual or
@@ -1728,7 +1962,8 @@ merge_file (finfo, vers)
         server_copy_file (finfo->file, finfo->update_dir, finfo->repository,
 			  backup);
 	server_updated (finfo, vers, SERVER_MERGED,
-			(struct stat *) NULL, (unsigned char *) NULL);
+			(mode_t) -1, (unsigned char *) NULL,
+			(struct buffer *) NULL);
     }
 #endif
 
@@ -1962,8 +2197,8 @@ join_file (finfo, vers)
 	if (server_active)
 	{
 	    server_scratch (finfo->file);
-	    server_updated (finfo, vers, SERVER_UPDATED, (struct stat *) NULL,
-			    (unsigned char *) NULL);
+	    server_updated (finfo, vers, SERVER_UPDATED, (mode_t) -1,
+			    (unsigned char *) NULL, (struct buffer *) NULL);
 	}
 #endif
 	mrev = xmalloc (strlen (vers->vn_user) + 2);
@@ -2016,14 +2251,7 @@ join_file (finfo, vers)
 
 	    /* FIXME: If checkout_file fails, we should arrange to
                return a non-zero exit status.  */
-	    status = checkout_file (finfo, xvers, 1);
-
-#ifdef SERVER_SUPPORT
-	    if (server_active && status == 0)
-		server_updated (finfo, xvers,
-				SERVER_UPDATED, (struct stat *) NULL,
-				(unsigned char *) NULL);
-#endif
+	    status = checkout_file (finfo, xvers, 1, 0, 1);
 
 	    freevers_ts (&xvers);
 
@@ -2085,7 +2313,7 @@ join_file (finfo, vers)
 				(char *) NULL, RUN_TTY,
 				(RCSCHECKOUTPROC) NULL, (void *) NULL);
 	if (retcode != 0)
-	    error (1, retcode == -1 ? errno : 0,
+	    error (1, 0,
 		   "failed to check out %s file", finfo->fullname);
     }
 #endif
@@ -2158,9 +2386,11 @@ join_file (finfo, vers)
 	write_letter (finfo, 'U');
     }
     else if (strcmp (options, "-kb") == 0
-	     || wrap_merge_is_copy (finfo->file))
+	     || wrap_merge_is_copy (finfo->file)
+	     || special_file_mismatch (finfo, rev1, rev2))
     {
-	/* We are dealing with binary files, but real merging would
+	/* We are dealing with binary files, or files with a
+	   permission/linkage mismatch, and real merging would
 	   need to take place.  This is a conflict.  We give the user
 	   the two files, and let them resolve it.  It is possible
 	   that we should require a "touch foo" or similar step before
@@ -2238,12 +2468,318 @@ join_file (finfo, vers)
 	server_copy_file (finfo->file, finfo->update_dir, finfo->repository,
 			  backup);
 	server_updated (finfo, vers, SERVER_MERGED,
-			(struct stat *) NULL, (unsigned char *) NULL);
+			(mode_t) -1, (unsigned char *) NULL,
+			(struct buffer *) NULL);
     }
 #endif
     free (backup);
 }
 
+/*
+ * Report whether revisions REV1 and REV2 of FINFO agree on:
+ *   . file ownership
+ *   . permissions
+ *   . major and minor device numbers
+ *   . symbolic links
+ *   . hard links
+ *
+ * If either REV1 or REV2 is NULL, the working copy is used instead.
+ *
+ * Return 1 if the files differ on these data.
+ */
+
+int
+special_file_mismatch (finfo, rev1, rev2)
+    struct file_info *finfo;
+    char *rev1;
+    char *rev2;
+{
+#ifdef PRESERVE_PERMISSIONS_SUPPORT
+    struct stat sb;
+    RCSVers *vp;
+    Node *n;
+    uid_t rev1_uid, rev2_uid;
+    gid_t rev1_gid, rev2_gid;
+    mode_t rev1_mode, rev2_mode;
+    unsigned long dev_long;
+    dev_t rev1_dev, rev2_dev;
+    char *rev1_symlink = NULL;
+    char *rev2_symlink = NULL;
+    char *rev1_hardlinks = NULL;
+    char *rev2_hardlinks = NULL;
+    int check_uids, check_gids, check_modes;
+    int result;
+
+    /* If we don't care about special file info, then
+       don't report a mismatch in any case. */
+    if (!preserve_perms)
+	return 0;
+
+    /* When special_file_mismatch is called from No_Difference, the
+       RCS file has been only partially parsed.  We must read the
+       delta tree in order to compare special file info recorded in
+       the delta nodes.  (I think this is safe. -twp) */
+    if (finfo->rcs->flags & PARTIAL)
+	RCS_reparsercsfile (finfo->rcs, NULL, NULL);
+
+    check_uids = check_gids = check_modes = 1;
+
+    /* Obtain file information for REV1.  If this is null, then stat
+       finfo->file and use that info. */
+    /* If a revision does not know anything about its status,
+       then presumably it doesn't matter, and indicates no conflict. */
+
+    if (rev1 == NULL)
+    {
+	if (islink (finfo->file))
+	    rev1_symlink = xreadlink (finfo->file);
+	else
+	{
+	    if (CVS_LSTAT (finfo->file, &sb) < 0)
+		error (1, errno, "could not get file information for %s",
+		       finfo->file);
+	    rev1_uid = sb.st_uid;
+	    rev1_gid = sb.st_gid;
+	    rev1_mode = sb.st_mode;
+	    if (S_ISBLK (rev1_mode) || S_ISCHR (rev1_mode))
+		rev1_dev = sb.st_rdev;
+	}
+	rev1_hardlinks = list_files_linked_to (finfo->file);
+    }
+    else
+    {
+	n = findnode (finfo->rcs->versions, rev1);
+	vp = (RCSVers *) n->data;
+
+	n = findnode (vp->other_delta, "symlink");
+	if (n != NULL)
+	    rev1_symlink = xstrdup (n->data);
+	else
+	{
+	    n = findnode (vp->other_delta, "owner");
+	    if (n == NULL)
+		check_uids = 0;	/* don't care */
+	    else
+		rev1_uid = strtoul (n->data, NULL, 10);
+
+	    n = findnode (vp->other_delta, "group");
+	    if (n == NULL)
+		check_gids = 0;	/* don't care */
+	    else
+		rev1_gid = strtoul (n->data, NULL, 10);
+
+	    n = findnode (vp->other_delta, "permissions");
+	    if (n == NULL)
+		check_modes = 0;	/* don't care */
+	    else
+		rev1_mode = strtoul (n->data, NULL, 8);
+
+	    n = findnode (vp->other_delta, "special");
+	    if (n == NULL)
+		rev1_mode |= S_IFREG;
+	    else
+	    {
+		/* If the size of `ftype' changes, fix the sscanf call also */
+		char ftype[16];
+		if (sscanf (n->data, "%16s %lu", ftype,
+			    &dev_long) < 2)
+		    error (1, 0, "%s:%s has bad `special' newphrase %s",
+			   finfo->file, rev1, n->data);
+		rev1_dev = dev_long;
+		if (strcmp (ftype, "character") == 0)
+		    rev1_mode |= S_IFCHR;
+		else if (strcmp (ftype, "block") == 0)
+		    rev1_mode |= S_IFBLK;
+		else
+		    error (0, 0, "%s:%s unknown file type `%s'",
+			   finfo->file, rev1, ftype);
+	    }
+
+	    n = findnode (vp->other_delta, "hardlinks");
+	    if (n == NULL)
+		rev1_hardlinks = xstrdup ("");
+	    else
+		rev1_hardlinks = xstrdup (n->data);
+	}
+    }
+
+    /* Obtain file information for REV2. */
+    if (rev2 == NULL)
+    {
+	if (islink (finfo->file))
+	    rev2_symlink = xreadlink (finfo->file);
+	else
+	{
+	    if (CVS_LSTAT (finfo->file, &sb) < 0)
+		error (1, errno, "could not get file information for %s",
+		       finfo->file);
+	    rev2_uid = sb.st_uid;
+	    rev2_gid = sb.st_gid;
+	    rev2_mode = sb.st_mode;
+	    if (S_ISBLK (rev2_mode) || S_ISCHR (rev2_mode))
+		rev2_dev = sb.st_rdev;
+	}
+	rev2_hardlinks = list_files_linked_to (finfo->file);
+    }
+    else
+    {
+	n = findnode (finfo->rcs->versions, rev2);
+	vp = (RCSVers *) n->data;
+
+	n = findnode (vp->other_delta, "symlink");
+	if (n != NULL)
+	    rev2_symlink = xstrdup (n->data);
+	else
+	{
+	    n = findnode (vp->other_delta, "owner");
+	    if (n == NULL)
+		check_uids = 0;	/* don't care */
+	    else
+		rev2_uid = strtoul (n->data, NULL, 10);
+
+	    n = findnode (vp->other_delta, "group");
+	    if (n == NULL)
+		check_gids = 0;	/* don't care */
+	    else
+		rev2_gid = strtoul (n->data, NULL, 10);
+
+	    n = findnode (vp->other_delta, "permissions");
+	    if (n == NULL)
+		check_modes = 0;	/* don't care */
+	    else
+		rev2_mode = strtoul (n->data, NULL, 8);
+
+	    n = findnode (vp->other_delta, "special");
+	    if (n == NULL)
+		rev2_mode |= S_IFREG;
+	    else
+	    {
+		/* If the size of `ftype' changes, fix the sscanf call also */
+		char ftype[16];
+		if (sscanf (n->data, "%16s %lu", ftype,
+			    &dev_long) < 2)
+		    error (1, 0, "%s:%s has bad `special' newphrase %s",
+			   finfo->file, rev2, n->data);
+		rev2_dev = dev_long;
+		if (strcmp (ftype, "character") == 0)
+		    rev2_mode |= S_IFCHR;
+		else if (strcmp (ftype, "block") == 0)
+		    rev2_mode |= S_IFBLK;
+		else
+		    error (0, 0, "%s:%s unknown file type `%s'",
+			   finfo->file, rev2, ftype);
+	    }
+
+	    n = findnode (vp->other_delta, "hardlinks");
+	    if (n == NULL)
+		rev2_hardlinks = xstrdup ("");
+	    else
+		rev2_hardlinks = xstrdup (n->data);
+	}
+    }
+
+    /* Check the user/group ownerships and file permissions, printing
+       an error for each mismatch found.  Return 0 if all characteristics
+       matched, and 1 otherwise. */
+
+    result = 0;
+
+    /* Compare symlinks first, since symlinks are simpler (don't have
+       any other characteristics). */
+    if (rev1_symlink != NULL && rev2_symlink == NULL)
+    {
+	error (0, 0, "%s is a symbolic link",
+	       (rev1 == NULL ? "working file" : rev1));
+	result = 1;
+    }
+    else if (rev1_symlink == NULL && rev2_symlink != NULL)
+    {
+	error (0, 0, "%s is a symbolic link",
+	       (rev2 == NULL ? "working file" : rev2));
+	result = 1;
+    }
+    else if (rev1_symlink != NULL)
+	result = (strcmp (rev1_symlink, rev2_symlink) == 0);
+    else
+    {
+	/* Compare user ownership. */
+	if (check_uids && rev1_uid != rev2_uid)
+	{
+	    error (0, 0, "%s: owner mismatch between %s and %s",
+		   finfo->file,
+		   (rev1 == NULL ? "working file" : rev1),
+		   (rev2 == NULL ? "working file" : rev2));
+	    result = 1;
+	}
+
+	/* Compare group ownership. */
+	if (check_gids && rev1_gid != rev2_gid)
+	{
+	    error (0, 0, "%s: group mismatch between %s and %s",
+		   finfo->file,
+		   (rev1 == NULL ? "working file" : rev1),
+		   (rev2 == NULL ? "working file" : rev2));
+	    result = 1;
+	}
+    
+	/* Compare permissions. */
+	if (check_modes &&
+	    (rev1_mode & 07777) != (rev2_mode & 07777))
+	{
+	    error (0, 0, "%s: permission mismatch between %s and %s",
+		   finfo->file,
+		   (rev1 == NULL ? "working file" : rev1),
+		   (rev2 == NULL ? "working file" : rev2));
+	    result = 1;
+	}
+
+	/* Compare device file characteristics. */
+	if ((rev1_mode & S_IFMT) != (rev2_mode & S_IFMT))
+	{
+	    error (0, 0, "%s: %s and %s are different file types",
+		   finfo->file,
+		   (rev1 == NULL ? "working file" : rev1),
+		   (rev2 == NULL ? "working file" : rev2));
+	    result = 1;
+	}
+	else if (S_ISBLK (rev1_mode))
+	{
+	    if (rev1_dev != rev2_dev)
+	    {
+		error (0, 0, "%s: device numbers of %s and %s do not match",
+		       finfo->file,
+		       (rev1 == NULL ? "working file" : rev1),
+		       (rev2 == NULL ? "working file" : rev2));
+		result = 1;
+	    }
+	}
+
+	/* Compare hard links. */
+	if (strcmp (rev1_hardlinks, rev2_hardlinks) != 0)
+	{
+	    error (0, 0, "%s: hard linkage of %s and %s do not match",
+		   finfo->file,
+		   (rev1 == NULL ? "working file" : rev1),
+		   (rev2 == NULL ? "working file" : rev2));
+	    result = 1;
+	}
+    }
+
+    if (rev1_symlink != NULL)
+	free (rev1_symlink);
+    if (rev2_symlink != NULL)
+	free (rev2_symlink);
+    if (rev1_hardlinks != NULL)
+	free (rev1_hardlinks);
+    if (rev2_hardlinks != NULL)
+	free (rev2_hardlinks);
+
+    return result;
+#else
+    return 0;
+#endif
+}
+
 int
 joining ()
 {