8f4b2e8689
This allows for creating dangling symlinks with force applied:
# Before:
$ ln -sf non-existant target
ln: stat non-existent: No such file or directory
$ ls -l target
ls: lstat target: No such file or directory
# After:
$ ln -sf non-existant target
$ ls -l target
lrwxrwxrwx 1 eu users 12 May 08 07:50 target -> non-existent
This also allows creating relative non-dangling symlinks with force applied:
touch existant; mkdir dir
# Before
$ ln -sf ../existant dir
ln: stat ../existant: No such file or directory
$ ls -l dir
# After
$ ln -sf ../existant dir
$ ls -l dir
lrwxrwxrwx 1 eu users 11 May 08 07:53 existant -> ../existant
The check for whether each src and to pairs are on the same device with the
same inode are only needed for hardlinks so that a forcefull link does
not remove the underlying file:
touch f; mkdir dir
# Before:
$ ln -f f f dir
ln: f and f are the same file
$ ls -i f dir/f
3670611 dir/f
3670611 f
# After:
$ ln -f f f dir
ln: f and f are the same file
$ ls -i f dir/f
4332236 dir/f
4332236 f
86 lines
1.7 KiB
C
86 lines
1.7 KiB
C
/* See LICENSE file for copyright and license details. */
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#include <sys/stat.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <libgen.h>
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#include <unistd.h>
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#include "util.h"
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static void
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usage(void)
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{
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eprintf("usage: %s [-f] [-L | -P | -s] target [name]\n"
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" %s [-f] [-L | -P | -s] target ... dir\n", argv0, argv0);
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}
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int
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main(int argc, char *argv[])
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{
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char *fname, *to;
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int sflag = 0, fflag = 0, hasto = 0, dirfd = AT_FDCWD, flags = AT_SYMLINK_FOLLOW;
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struct stat st, tost;
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ARGBEGIN {
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case 'f':
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fflag = 1;
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break;
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case 'L':
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flags |= AT_SYMLINK_FOLLOW;
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break;
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case 'P':
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flags &= ~AT_SYMLINK_FOLLOW;
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break;
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case 's':
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sflag = 1;
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break;
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default:
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usage();
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} ARGEND;
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if (!argc)
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usage();
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fname = sflag ? "symlink" : "link";
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if (argc >= 2) {
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if (!stat(argv[argc - 1], &st) && S_ISDIR(st.st_mode)) {
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if ((dirfd = open(argv[argc - 1], O_RDONLY)) < 0)
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eprintf("open %s:", argv[argc - 1]);
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} else if (argc == 2) {
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to = argv[argc - 1];
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hasto = 1;
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} else {
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eprintf("%s: not a directory\n", argv[argc - 1]);
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}
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argv[argc - 1] = NULL;
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argc--;
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}
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for (; *argv; argc--, argv++) {
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if (!hasto)
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to = basename(*argv);
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if (!sflag) {
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if (stat(*argv, &st) < 0) {
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weprintf("stat %s:", *argv);
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continue;
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} else if (fstatat(dirfd, to, &tost, AT_SYMLINK_NOFOLLOW) < 0) {
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if (errno != ENOENT)
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eprintf("stat %s:", to);
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} else if (st.st_dev == tost.st_dev && st.st_ino == tost.st_ino) {
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weprintf("%s and %s are the same file\n", *argv, *argv);
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continue;
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}
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}
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if (fflag)
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unlinkat(dirfd, to, 0);
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if ((!sflag ? linkat(AT_FDCWD, *argv, dirfd, to, flags)
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: symlinkat(*argv, dirfd, to)) < 0) {
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weprintf("%s %s <- %s:", fname, *argv, to);
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}
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}
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return 0;
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}
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