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/* $OpenBSD: ln.c,v 1.24 2016/05/10 20:20:43 tim Exp $ */
/* $NetBSD: ln.c,v 1.10 1995/03/21 09:06:10 cgd Exp $ */
/*
* Copyright (c) 1987, 1993, 1994
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <libgen.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <limits.h>
int fflag; /* Unlink existing files. */
int hflag; /* Check new name for symlink first. */
int Pflag; /* Hard link to symlink. */
int sflag; /* Symbolic, not hard, link. */
int linkit(char *, char *, int);
void usage(void) __dead;
int
main(int argc, char *argv[])
{
struct stat sb;
int ch, exitval;
char *sourcedir;
if (pledge("stdio rpath cpath", NULL) == -1)
err(1, "pledge");
while ((ch = getopt(argc, argv, "fhLnPs")) != -1)
switch (ch) {
case 'f':
fflag = 1;
break;
case 'h':
case 'n':
hflag = 1;
break;
case 'L':
Pflag = 0;
break;
case 'P':
Pflag = 1;
break;
case 's':
sflag = 1;
break;
default:
usage();
}
argv += optind;
argc -= optind;
switch(argc) {
case 0:
usage();
case 1: /* ln target */
exit(linkit(argv[0], ".", 1));
case 2: /* ln target source */
exit(linkit(argv[0], argv[1], 0));
}
/* ln target1 target2 directory */
sourcedir = argv[argc - 1];
if (stat(sourcedir, &sb))
err(1, "%s", sourcedir);
if (!S_ISDIR(sb.st_mode))
usage();
for (exitval = 0; *argv != sourcedir; ++argv)
exitval |= linkit(*argv, sourcedir, 1);
exit(exitval);
}
/*
* Nomenclature warning!
*
* In this source "target" and "source" are used the opposite way they
* are used in the ln(1) manual. Here "target" is the existing file and
* "source" specifies the to-be-created link to "target".
*/
int
linkit(char *target, char *source, int isdir)
{
struct stat sb;
char *p, path[PATH_MAX];
int (*statf)(const char *, struct stat *);
int exists, n;
if (!sflag) {
/* If target doesn't exist, quit now. */
if ((Pflag ? lstat : stat)(target, &sb)) {
warn("%s", target);
return (1);
}
/* Only symbolic links to directories. */
if (S_ISDIR(sb.st_mode)) {
warnc(EISDIR, "%s", target);
return (1);
}
}
statf = hflag ? lstat : stat;
/* If the source is a directory, append the target's name. */
if (isdir || (!statf(source, &sb) && S_ISDIR(sb.st_mode))) {
if ((p = basename(target)) == NULL) {
warn("%s", target);
return (1);
}
n = snprintf(path, sizeof(path), "%s/%s", source, p);
if (n < 0 || n >= sizeof(path)) {
warnc(ENAMETOOLONG, "%s/%s", source, p);
return (1);
}
source = path;
}
exists = (lstat(source, &sb) == 0);
/*
* If doing hard links and the source (destination) exists and it
* actually is the same file like the target (existing file), we
* complain that the files are identical. If -f is specified, we
* accept the job as already done and return with success.
*/
if (exists && !sflag) {
struct stat tsb;
if ((Pflag ? lstat : stat)(target, &tsb)) {
warn("%s: disappeared", target);
return (1);
}
if (tsb.st_dev == sb.st_dev && tsb.st_ino == sb.st_ino) {
if (fflag)
return (0);
else {
warnx("%s and %s are identical (nothing done).",
target, source);
return (1);
}
}
}
/*
* If the file exists, and -f was specified, unlink it.
* Attempt the link.
*/
if ((fflag && unlink(source) < 0 && errno != ENOENT) ||
(sflag ? symlink(target, source) :
linkat(AT_FDCWD, target, AT_FDCWD, source,
Pflag ? 0 : AT_SYMLINK_FOLLOW))) {
warn("%s", source);
return (1);
}
return (0);
}
void
usage(void)
{
extern char *__progname;
(void)fprintf(stderr,
"usage: %s [-fhLnPs] source [target]\n"
" %s [-fLPs] source ... [directory]\n",
__progname, __progname);
exit(1);
}
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