sftp support for resuming partial downloads; patch mostly by Loganaden

Velvindron/AfriNIC with some tweaks by me; feedback and ok dtucker@
"Just be careful" deraadt@

4 files changed, 129 insertions, 56 deletions

diff --git a/usr.bin/ssh/sftp-client.c b/usr.bin/ssh/sftp-client.c
index 5c3725f6cb4..b335e261b49 100644
--- a/usr.bin/ssh/sftp-client.c
+++ b/usr.bin/ssh/sftp-client.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sftp-client.c,v 1.100 2013/06/01 22:34:50 dtucker Exp $ */
+/* $OpenBSD: sftp-client.c,v 1.101 2013/07/25 00:56:51 djm Exp $ */
 /*
  * Copyright (c) 2001-2004 Damien Miller <djm@openbsd.org>
  *
@@ -105,7 +105,7 @@ send_msg(struct sftp_conn *conn, Buffer *m)
 	iov[1].iov_len = buffer_len(m);
 
 	if (atomiciov6(writev, conn->fd_out, iov, 2,
-	    conn->limit_kbps > 0 ? sftpio : NULL, &conn->bwlimit_out) != 
+	    conn->limit_kbps > 0 ? sftpio : NULL, &conn->bwlimit_out) !=
 	    buffer_len(m) + sizeof(mlen))
 		fatal("Couldn't send packet: %s", strerror(errno));
 
@@ -981,16 +981,17 @@ send_read_request(struct sftp_conn *conn, u_int id, u_int64_t offset,
 
 int
 do_download(struct sftp_conn *conn, char *remote_path, char *local_path,
-    Attrib *a, int pflag)
+    Attrib *a, int pflag, int resume)
 {
 	Attrib junk;
 	Buffer msg;
 	char *handle;
-	int local_fd, status = 0, write_error;
-	int read_error, write_errno;
-	u_int64_t offset, size;
+	int local_fd = -1, status = 0, write_error;
+	int read_error, write_errno, reordered = 0;
+	u_int64_t offset = 0, size, highwater;
 	u_int handle_len, mode, type, id, buflen, num_req, max_req;
 	off_t progress_counter;
+	struct stat st;
 	struct request {
 		u_int id;
 		u_int len;
@@ -1043,21 +1044,36 @@ do_download(struct sftp_conn *conn, char *remote_path, char *local_path,
 		return(-1);
 	}
 
-	local_fd = open(local_path, O_WRONLY | O_CREAT | O_TRUNC,
+	local_fd = open(local_path, O_WRONLY | O_CREAT | (resume ? : O_TRUNC),
 	    mode | S_IWUSR);
 	if (local_fd == -1) {
 		error("Couldn't open local file \"%s\" for writing: %s",
 		    local_path, strerror(errno));
-		do_close(conn, handle, handle_len);
-		buffer_free(&msg);
-		free(handle);
-		return(-1);
+		goto fail;
+	}
+	offset = highwater = 0;
+	if (resume) {
+		if (fstat(local_fd, &st) == -1) {
+			error("Unable to stat local file \"%s\": %s",
+			    local_path, strerror(errno));
+			goto fail;
+		}
+		if ((size_t)st.st_size > size) {
+			error("Unable to resume download of \"%s\": "
+			    "local file is larger than remote", local_path);
+ fail:
+			do_close(conn, handle, handle_len);
+			buffer_free(&msg);
+			free(handle);
+			return -1;
+		}
+		offset = highwater = st.st_size;
 	}
 
 	/* Read from remote and write to local */
-	write_error = read_error = write_errno = num_req = offset = 0;
+	write_error = read_error = write_errno = num_req = 0;
 	max_req = 1;
-	progress_counter = 0;
+	progress_counter = offset;
 
 	if (showprogress && size != 0)
 		start_progress_meter(remote_path, size, &progress_counter);
@@ -1132,6 +1148,10 @@ do_download(struct sftp_conn *conn, char *remote_path, char *local_path,
 				write_error = 1;
 				max_req = 0;
 			}
+			else if (!reordered && req->offset <= highwater)
+				highwater = req->offset + len;
+			else if (!reordered && req->offset > highwater)
+				reordered = 1;
 			progress_counter += len;
 			free(data);
 
@@ -1180,7 +1200,15 @@ do_download(struct sftp_conn *conn, char *remote_path, char *local_path,
 	/* Sanity check */
 	if (TAILQ_FIRST(&requests) != NULL)
 		fatal("Transfer complete, but requests still in queue");
-
+	/* Truncate at highest contiguous point to avoid holes on interrupt */
+	if (read_error || write_error || interrupted) {
+		if (reordered && resume) {
+			error("Unable to resume download of \"%s\": "
+			    "server reordered requests", local_path);
+		}
+		debug("truncating at %llu", (unsigned long long)highwater);
+		ftruncate(local_fd, highwater);
+	}
 	if (read_error) {
 		error("Couldn't read from remote file \"%s\" : %s",
 		    remote_path, fx2txt(status));
@@ -1192,7 +1220,8 @@ do_download(struct sftp_conn *conn, char *remote_path, char *local_path,
 		do_close(conn, handle, handle_len);
 	} else {
 		status = do_close(conn, handle, handle_len);
-
+		if (interrupted)
+			status = -1;
 		/* Override umask and utimes if asked */
 		if (pflag && fchmod(local_fd, mode) == -1)
 			error("Couldn't set mode on \"%s\": %s", local_path,
@@ -1216,7 +1245,7 @@ do_download(struct sftp_conn *conn, char *remote_path, char *local_path,
 
 static int
 download_dir_internal(struct sftp_conn *conn, char *src, char *dst,
-    Attrib *dirattrib, int pflag, int printflag, int depth)
+    Attrib *dirattrib, int pflag, int printflag, int depth, int resume)
 {
 	int i, ret = 0;
 	SFTP_DIRENT **dir_entries;
@@ -1269,11 +1298,11 @@ download_dir_internal(struct sftp_conn *conn, char *src, char *dst,
 				continue;
 			if (download_dir_internal(conn, new_src, new_dst,
 			    &(dir_entries[i]->a), pflag, printflag,
-			    depth + 1) == -1)
+			    depth + 1, resume) == -1)
 				ret = -1;
 		} else if (S_ISREG(dir_entries[i]->a.perm) ) {
 			if (do_download(conn, new_src, new_dst,
-			    &(dir_entries[i]->a), pflag) == -1) {
+			    &(dir_entries[i]->a), pflag, resume) == -1) {
 				error("Download of file %s to %s failed",
 				    new_src, new_dst);
 				ret = -1;
@@ -1306,7 +1335,7 @@ download_dir_internal(struct sftp_conn *conn, char *src, char *dst,
 
 int
 download_dir(struct sftp_conn *conn, char *src, char *dst,
-    Attrib *dirattrib, int pflag, int printflag)
+    Attrib *dirattrib, int pflag, int printflag, int resume)
 {
 	char *src_canon;
 	int ret;
@@ -1317,7 +1346,7 @@ download_dir(struct sftp_conn *conn, char *src, char *dst,
 	}
 
 	ret = download_dir_internal(conn, src_canon, dst,
-	    dirattrib, pflag, printflag, 0);
+	    dirattrib, pflag, printflag, 0, resume);
 	free(src_canon);
 	return ret;
 }
@@ -1541,7 +1570,7 @@ upload_dir_internal(struct sftp_conn *conn, char *src, char *dst,
 	a.perm &= 01777;
 	if (!pflag)
 		a.flags &= ~SSH2_FILEXFER_ATTR_ACMODTIME;
-	
+
 	status = do_mkdir(conn, dst, &a, 0);
 	/*
 	 * we lack a portable status for errno EEXIST,
@@ -1551,7 +1580,7 @@ upload_dir_internal(struct sftp_conn *conn, char *src, char *dst,
 	if (status != SSH2_FX_OK) {
 		if (status != SSH2_FX_FAILURE)
 			return -1;
-		if (do_stat(conn, dst, 0) == NULL) 
+		if (do_stat(conn, dst, 0) == NULL)
 			return -1;
 	}
 
@@ -1559,7 +1588,7 @@ upload_dir_internal(struct sftp_conn *conn, char *src, char *dst,
 		error("Failed to open dir \"%s\": %s", src, strerror(errno));
 		return -1;
 	}
-	
+
 	while (((dp = readdir(dirp)) != NULL) && !interrupted) {
 		if (dp->d_ino == 0)
 			continue;
diff --git a/usr.bin/ssh/sftp-client.h b/usr.bin/ssh/sftp-client.h
index aef54ef49dd..111a998c84c 100644
--- a/usr.bin/ssh/sftp-client.h
+++ b/usr.bin/ssh/sftp-client.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: sftp-client.h,v 1.20 2010/12/04 00:18:01 djm Exp $ */
+/* $OpenBSD: sftp-client.h,v 1.21 2013/07/25 00:56:51 djm Exp $ */
 
 /*
  * Copyright (c) 2001-2004 Damien Miller <djm@openbsd.org>
@@ -106,13 +106,13 @@ int do_symlink(struct sftp_conn *, char *, char *);
  * Download 'remote_path' to 'local_path'. Preserve permissions and times
  * if 'pflag' is set
  */
-int do_download(struct sftp_conn *, char *, char *, Attrib *, int);
+int do_download(struct sftp_conn *, char *, char *, Attrib *, int, int);
 
 /*
  * Recursively download 'remote_directory' to 'local_directory'. Preserve 
  * times if 'pflag' is set
  */
-int download_dir(struct sftp_conn *, char *, char *, Attrib *, int, int);
+int download_dir(struct sftp_conn *, char *, char *, Attrib *, int, int, int);
 
 /*
  * Upload 'local_path' to 'remote_path'. Preserve permissions and times
diff --git a/usr.bin/ssh/sftp.1 b/usr.bin/ssh/sftp.1
index bcb4721449f..2577fe87551 100644
--- a/usr.bin/ssh/sftp.1
+++ b/usr.bin/ssh/sftp.1
@@ -1,4 +1,4 @@
-.\" $OpenBSD: sftp.1,v 1.91 2011/09/05 05:56:13 djm Exp $
+.\" $OpenBSD: sftp.1,v 1.92 2013/07/25 00:56:51 djm Exp $
 .\"
 .\" Copyright (c) 2001 Damien Miller.  All rights reserved.
 .\"
@@ -22,7 +22,7 @@
 .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd $Mdocdate: September 5 2011 $
+.Dd $Mdocdate: July 25 2013 $
 .Dt SFTP 1
 .Os
 .Sh NAME
@@ -129,7 +129,7 @@ may be used to indicate standard input.
 .Nm
 will abort if any of the following
 commands fail:
-.Ic get , put , rename , ln ,
+.Ic get , put , reget , rename , ln ,
 .Ic rm , mkdir , chdir , ls ,
 .Ic lchdir , chmod , chown ,
 .Ic chgrp , lpwd , df , symlink ,
@@ -343,7 +343,7 @@ extension.
 Quit
 .Nm sftp .
 .It Xo Ic get
-.Op Fl Ppr
+.Op Fl aPpr
 .Ar remote-path
 .Op Ar local-path
 .Xc
@@ -363,6 +363,14 @@ is specified, then
 .Ar local-path
 must specify a directory.
 .Pp
+If the
+.Fl a
+flag is specified, then attempt to resume partial transfers of existing files.
+Note that resumption assumes that any partial copy of the local file matches
+the remote copy.
+If the remote file differs from the partial local copy then the resultant file
+is likely to be corrupt.
+.Pp
 If either the
 .Fl P
 or
@@ -503,6 +511,18 @@ Display remote working directory.
 .It Ic quit
 Quit
 .Nm sftp .
+.It Xo Ic reget
+.Op Fl Ppr
+.Ar remote-path
+.Op Ar local-path
+.Xc
+Resume download of
+.Ar remote-path .
+Equivalent to
+.Ic get
+with the
+.Fl a
+flag set.
 .It Ic rename Ar oldpath Ar newpath
 Rename remote file from
 .Ar oldpath
diff --git a/usr.bin/ssh/sftp.c b/usr.bin/ssh/sftp.c
index 1a2d3b2dbc7..d495fd81c2c 100644
--- a/usr.bin/ssh/sftp.c
+++ b/usr.bin/ssh/sftp.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sftp.c,v 1.147 2013/07/12 00:20:00 djm Exp $ */
+/* $OpenBSD: sftp.c,v 1.148 2013/07/25 00:56:52 djm Exp $ */
 /*
  * Copyright (c) 2001-2004 Damien Miller <djm@openbsd.org>
  *
@@ -69,6 +69,9 @@ int showprogress = 1;
 /* When this option is set, we always recursively download/upload directories */
 int global_rflag = 0;
 
+/* When this option is set, we resume download if possible */
+int global_aflag = 0;
+
 /* When this option is set, the file transfers will always preserve times */
 int global_pflag = 0;
 
@@ -130,6 +133,7 @@ int remote_glob(struct sftp_conn *, const char *, int,
 #define I_SYMLINK	21
 #define I_VERSION	22
 #define I_PROGRESS	23
+#define I_REGET		26
 
 struct CMD {
 	const char *c;
@@ -169,6 +173,7 @@ static const struct CMD cmds[] = {
 	{ "put",	I_PUT,		LOCAL	},
 	{ "pwd",	I_PWD,		REMOTE	},
 	{ "quit",	I_QUIT,		NOARGS	},
+	{ "reget",	I_REGET,	REMOTE	},
 	{ "rename",	I_RENAME,	REMOTE	},
 	{ "rm",		I_RM,		REMOTE	},
 	{ "rmdir",	I_RMDIR,	REMOTE	},
@@ -218,6 +223,7 @@ help(void)
 	    "                                   filesystem containing 'path'\n"
 	    "exit                               Quit sftp\n"
 	    "get [-Ppr] remote [local]          Download file\n"
+	    "reget remote [local]		Resume download file\n"
 	    "help                               Display this help text\n"
 	    "lcd path                           Change local directory to 'path'\n"
 	    "lls [ls-options [path]]            Display local directory listing\n"
@@ -329,8 +335,8 @@ make_absolute(char *p, char *pwd)
 }
 
 static int
-parse_getput_flags(const char *cmd, char **argv, int argc, int *pflag,
-    int *rflag)
+parse_getput_flags(const char *cmd, char **argv, int argc,
+    int *aflag, int *pflag, int *rflag)
 {
 	extern int opterr, optind, optopt, optreset;
 	int ch;
@@ -338,9 +344,12 @@ parse_getput_flags(const char *cmd, char **argv, int argc, int *pflag,
 	optind = optreset = 1;
 	opterr = 0;
 
-	*rflag = *pflag = 0;
-	while ((ch = getopt(argc, argv, "PpRr")) != -1) {
+	*aflag = *rflag = *pflag = 0;
+	while ((ch = getopt(argc, argv, "aPpRr")) != -1) {
 		switch (ch) {
+		case 'a':
+			*aflag = 1;
+			break;
 		case 'p':
 		case 'P':
 			*pflag = 1;
@@ -498,7 +507,7 @@ pathname_is_dir(char *pathname)
 
 static int
 process_get(struct sftp_conn *conn, char *src, char *dst, char *pwd,
-    int pflag, int rflag)
+    int pflag, int rflag, int resume)
 {
 	char *abs_src = NULL;
 	char *abs_dst = NULL;
@@ -550,15 +559,18 @@ process_get(struct sftp_conn *conn, char *src, char *dst, char *pwd,
 		}
 		free(tmp);
 
-		if (!quiet)
+		resume |= global_aflag;
+		if (!quiet && resume)
+			printf("Resuming %s to %s\n", g.gl_pathv[i], abs_dst);
+		else if (!quiet && !resume)
 			printf("Fetching %s to %s\n", g.gl_pathv[i], abs_dst);
 		if (pathname_is_dir(g.gl_pathv[i]) && (rflag || global_rflag)) {
-			if (download_dir(conn, g.gl_pathv[i], abs_dst, NULL, 
-			    pflag || global_pflag, 1) == -1)
+			if (download_dir(conn, g.gl_pathv[i], abs_dst, NULL,
+			    pflag || global_pflag, 1, resume) == -1)
 				err = -1;
 		} else {
 			if (do_download(conn, g.gl_pathv[i], abs_dst, NULL,
-			    pflag || global_pflag) == -1)
+			    pflag || global_pflag, resume) == -1)
 				err = -1;
 		}
 		free(abs_dst);
@@ -1097,8 +1109,9 @@ makeargv(const char *arg, int *argcp, int sloppy, char *lastquote,
 }
 
 static int
-parse_args(const char **cpp, int *pflag, int *rflag, int *lflag, int *iflag,
-    int *hflag, int *sflag, unsigned long *n_arg, char **path1, char **path2)
+parse_args(const char **cpp, int *aflag, int *hflag, int *iflag, int *lflag,
+    int *pflag, int *rflag, int *sflag, unsigned long *n_arg,
+    char **path1, char **path2)
 {
 	const char *cmd, *cp = *cpp;
 	char *cp2, **argv;
@@ -1142,14 +1155,15 @@ parse_args(const char **cpp, int *pflag, int *rflag, int *lflag, int *iflag,
 	}
 
 	/* Get arguments and parse flags */
-	*lflag = *pflag = *rflag = *hflag = *n_arg = 0;
+	*aflag = *lflag = *pflag = *rflag = *hflag = *n_arg = 0;
 	*path1 = *path2 = NULL;
 	optidx = 1;
 	switch (cmdnum) {
 	case I_GET:
+	case I_REGET:
 	case I_PUT:
 		if ((optidx = parse_getput_flags(cmd, argv, argc,
-		    pflag, rflag)) == -1)
+		    aflag, pflag, rflag)) == -1)
 			return -1;
 		/* Get first pathname (mandatory) */
 		if (argc - optidx < 1) {
@@ -1164,6 +1178,11 @@ parse_args(const char **cpp, int *pflag, int *rflag, int *lflag, int *iflag,
 			/* Destination is not globbed */
 			undo_glob_escape(*path2);
 		}
+		if (*aflag && cmdnum == I_PUT) {
+			/* XXX implement resume for uploads */
+			error("Resume is not supported for uploads");
+			return -1;
+		}
 		break;
 	case I_LINK:
 		if ((optidx = parse_link_flags(cmd, argv, argc, sflag)) == -1)
@@ -1272,7 +1291,8 @@ parse_dispatch_command(struct sftp_conn *conn, const char *cmd, char **pwd,
     int err_abort)
 {
 	char *path1, *path2, *tmp;
-	int pflag = 0, rflag = 0, lflag = 0, iflag = 0, hflag = 0, sflag = 0;
+	int aflag = 0, hflag = 0, iflag = 0, lflag = 0, pflag = 0;
+	int rflag = 0, sflag = 0;
 	int cmdnum, i;
 	unsigned long n_arg = 0;
 	Attrib a, *aa;
@@ -1281,9 +1301,8 @@ parse_dispatch_command(struct sftp_conn *conn, const char *cmd, char **pwd,
 	glob_t g;
 
 	path1 = path2 = NULL;
-	cmdnum = parse_args(&cmd, &pflag, &rflag, &lflag, &iflag, &hflag,
-	    &sflag, &n_arg, &path1, &path2);
-
+	cmdnum = parse_args(&cmd, &aflag, &hflag, &iflag, &lflag, &pflag,
+	    &rflag, &sflag, &n_arg, &path1, &path2);
 	if (iflag != 0)
 		err_abort = 0;
 
@@ -1298,8 +1317,12 @@ parse_dispatch_command(struct sftp_conn *conn, const char *cmd, char **pwd,
 		/* Unrecognized command */
 		err = -1;
 		break;
+	case I_REGET:
+		aflag = 1;
+		/* FALLTHROUGH */
 	case I_GET:
-		err = process_get(conn, path1, path2, *pwd, pflag, rflag);
+		err = process_get(conn, path1, path2, *pwd, pflag,
+		    rflag, aflag);
 		break;
 	case I_PUT:
 		err = process_put(conn, path1, path2, *pwd, pflag, rflag);
@@ -1924,12 +1947,10 @@ interactive_loop(struct sftp_conn *conn, char *file1, char *file2)
 			}
 		} else {
 			/* XXX this is wrong wrt quoting */
-			if (file2 == NULL)
-				snprintf(cmd, sizeof cmd, "get %s", dir);
-			else
-				snprintf(cmd, sizeof cmd, "get %s %s", dir,
-				    file2);
-
+			snprintf(cmd, sizeof cmd, "get%s %s%s%s",
+			    global_aflag ? " -a" : "", dir,
+			    file2 == NULL ? "" : " ",
+			    file2 == NULL ? "" : file2);
 			err = parse_dispatch_command(conn, cmd,
 			    &remote_path, 1);
 			free(dir);
@@ -2101,7 +2122,7 @@ main(int argc, char **argv)
 	infile = stdin;
 
 	while ((ch = getopt(argc, argv,
-	    "1246hpqrvCc:D:i:l:o:s:S:b:B:F:P:R:")) != -1) {
+	    "1246ahpqrvCc:D:i:l:o:s:S:b:B:F:P:R:")) != -1) {
 		switch (ch) {
 		/* Passed through to ssh(1) */
 		case '4':
@@ -2141,6 +2162,9 @@ main(int argc, char **argv)
 		case '2':
 			sshver = 2;
 			break;
+		case 'a':
+			global_aflag = 1;
+			break;
 		case 'B':
 			copy_buffer_len = strtol(optarg, &cp, 10);
 			if (copy_buffer_len == 0 || *cp != '\0')