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Fix ln(1) symbolic link handling 

This was broken in multiple ways. For instance, the overlay-
check of identical files (name and target) was omitted for
symbolic links for some reason.
While at it, I fixed the stat-handling, improved the error-
messages so the right paths were shown and removed the
illegimite bail-out when the target-fstatat failed (we want
only a warning here as well).
This commit is contained in:
FRIGN 2015-05-27 18:15:24 +02:00 committed by sin
parent d23cc72490
commit 78b285deb6
1 changed files with 35 additions and 26 deletions
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61
ln.c
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@ -4,6 +4,7 @@
#include <errno.h> #include <errno.h>
#include <fcntl.h> #include <fcntl.h>
#include <libgen.h> #include <libgen.h>
#include <string.h>
#include <unistd.h> #include <unistd.h>
#include "util.h" #include "util.h"
@ -18,10 +19,10 @@ usage(void)
int int
main(int argc, char *argv[]) main(int argc, char *argv[])
{ {
char *fname, *to; char *targetdir = ".", *target = NULL;
int sflag = 0, fflag = 0, hasto = 0, dirfd = AT_FDCWD, ret = 0, int ret = 0, sflag = 0, fflag = 0, dirfd = AT_FDCWD,
flags = AT_SYMLINK_FOLLOW; hastarget = 0, flags = AT_SYMLINK_FOLLOW;
struct stat st, tost; struct stat st, tst;
ARGBEGIN { ARGBEGIN {
case 'f': case 'f':
@ -43,15 +44,16 @@ main(int argc, char *argv[])
if (!argc) if (!argc)
usage(); usage();
fname = sflag ? "symlink" : "link"; if (argc > 1) {
if (argc >= 2) {
if (!stat(argv[argc - 1], &st) && S_ISDIR(st.st_mode)) { if (!stat(argv[argc - 1], &st) && S_ISDIR(st.st_mode)) {
if ((dirfd = open(argv[argc - 1], O_RDONLY)) < 0) if ((dirfd = open(argv[argc - 1], O_RDONLY)) < 0)
eprintf("open %s:", argv[argc - 1]); eprintf("open %s:", argv[argc - 1]);
targetdir = argv[argc - 1];
if (targetdir[strlen(targetdir) - 1] == '/')
targetdir[strlen(targetdir) - 1] = '\0';
} else if (argc == 2) { } else if (argc == 2) {
to = argv[argc - 1]; hastarget = 1;
hasto = 1; target = argv[argc - 1];
} else { } else {
eprintf("%s: not a directory\n", argv[argc - 1]); eprintf("%s: not a directory\n", argv[argc - 1]);
} }
@ -60,27 +62,34 @@ main(int argc, char *argv[])
} }
for (; *argv; argc--, argv++) { for (; *argv; argc--, argv++) {
if (!hasto) if (!hastarget)
to = basename(*argv); target = basename(*argv);
if (!sflag) {
if (stat(*argv, &st) < 0) { if (stat(*argv, &st) < 0) {
weprintf("stat %s:", *argv); weprintf("stat %s:", *argv);
ret = 1; ret = 1;
continue; continue;
} else if (fstatat(dirfd, to, &tost, AT_SYMLINK_NOFOLLOW) < 0) { } else if (fstatat(dirfd, target, &tst, AT_SYMLINK_NOFOLLOW) < 0) {
if (errno != ENOENT) if (errno != ENOENT) {
eprintf("stat %s:", to); weprintf("fstatat %s %s:", targetdir, target);
} else if (st.st_dev == tost.st_dev && st.st_ino == tost.st_ino) {
weprintf("%s and %s are the same file\n", *argv, *argv);
ret = 1; ret = 1;
continue; continue;
} }
} else if (st.st_dev == tst.st_dev && st.st_ino == tst.st_ino) {
weprintf("%s and %s/%s are the same file\n", *argv, targetdir, target);
ret = 1;
continue;
} }
if (fflag)
unlinkat(dirfd, to, 0); if (fflag && unlinkat(dirfd, target, 0) < 0 && errno != ENOENT) {
if ((!sflag ? linkat(AT_FDCWD, *argv, dirfd, to, flags) weprintf("unlinkat %s %s:", targetdir, target);
: symlinkat(*argv, dirfd, to)) < 0) { ret = 1;
weprintf("%s %s <- %s:", fname, *argv, to); continue;
}
if ((sflag ? symlinkat(*argv, dirfd, target) :
linkat(AT_FDCWD, *argv, dirfd, target, flags)) < 0) {
weprintf("%s %s <- %s/%s:", sflag ? "symlinkat" : "linkat",
*argv, targetdir, target);
ret = 1; ret = 1;
} }
} }