[hackers] [sbase] Fix ln(1) symbolic link handling || FRIGN

From: <git_AT_suckless.org>
Date: Fri, 29 May 2015 13:08:43 +0200 (CEST)

commit 78b285deb6c5e6770621223b3364eca1174d8e28
Author: FRIGN <dev_AT_frign.de>
Date: Wed May 27 18:15:24 2015 +0200

    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).

diff --git a/ln.c b/ln.c
index bbda821..6e40c8f 100644
--- a/ln.c
+++ b/ln.c
_AT_@ -4,6 +4,7 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <libgen.h>
+#include <string.h>
 #include <unistd.h>
 
 #include "util.h"
_AT_@ -18,10 +19,10 @@ usage(void)
 int
 main(int argc, char *argv[])
 {
- char *fname, *to;
- int sflag = 0, fflag = 0, hasto = 0, dirfd = AT_FDCWD, ret = 0,
- flags = AT_SYMLINK_FOLLOW;
- struct stat st, tost;
+ char *targetdir = ".", *target = NULL;
+ int ret = 0, sflag = 0, fflag = 0, dirfd = AT_FDCWD,
+ hastarget = 0, flags = AT_SYMLINK_FOLLOW;
+ struct stat st, tst;
 
         ARGBEGIN {
         case 'f':
_AT_@ -43,15 +44,16 @@ main(int argc, char *argv[])
         if (!argc)
                 usage();
 
- fname = sflag ? "symlink" : "link";
-
- if (argc >= 2) {
+ if (argc > 1) {
                 if (!stat(argv[argc - 1], &st) && S_ISDIR(st.st_mode)) {
                         if ((dirfd = open(argv[argc - 1], O_RDONLY)) < 0)
                                 eprintf("open %s:", argv[argc - 1]);
+ targetdir = argv[argc - 1];
+ if (targetdir[strlen(targetdir) - 1] == '/')
+ targetdir[strlen(targetdir) - 1] = '\0';
                 } else if (argc == 2) {
- to = argv[argc - 1];
- hasto = 1;
+ hastarget = 1;
+ target = argv[argc - 1];
                 } else {
                         eprintf("%s: not a directory\n", argv[argc - 1]);
                 }
_AT_@ -60,27 +62,34 @@ main(int argc, char *argv[])
         }
 
         for (; *argv; argc--, argv++) {
- if (!hasto)
- to = basename(*argv);
- if (!sflag) {
- if (stat(*argv, &st) < 0) {
- weprintf("stat %s:", *argv);
- ret = 1;
- continue;
- } else if (fstatat(dirfd, to, &tost, AT_SYMLINK_NOFOLLOW) < 0) {
- if (errno != ENOENT)
- eprintf("stat %s:", to);
- } 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);
+ if (!hastarget)
+ target = basename(*argv);
+
+ if (stat(*argv, &st) < 0) {
+ weprintf("stat %s:", *argv);
+ ret = 1;
+ continue;
+ } else if (fstatat(dirfd, target, &tst, AT_SYMLINK_NOFOLLOW) < 0) {
+ if (errno != ENOENT) {
+ weprintf("fstatat %s %s:", targetdir, target);
                                 ret = 1;
                                 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, target, 0) < 0 && errno != ENOENT) {
+ weprintf("unlinkat %s %s:", targetdir, target);
+ ret = 1;
+ continue;
                 }
- if (fflag)
- unlinkat(dirfd, to, 0);
- if ((!sflag ? linkat(AT_FDCWD, *argv, dirfd, to, flags)
- : symlinkat(*argv, dirfd, to)) < 0) {
- weprintf("%s %s <- %s:", fname, *argv, to);
+ 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;
                 }
         }
Received on Fri May 29 2015 - 13:08:43 CEST