readlink: use xmalloc_realpath()

Using realpath() directly with a non-NULL output buffer is unsafe because its
behavior is unspecified on systems which don't have PATH_MAX (ie. Hurd)

I beleive this also fixes a small bug whereby 'buf' would not be freed
on 'readlink -v' with ENABLE_FEATURE_CLEANUP.

Signed-off-by: Jeremie Koenig <jk@jk.fr.eu.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 2 insertions, 3 deletions

diff --git a/coreutils/readlink.c b/coreutils/readlink.c
index 20df38b96..2ed5e2cac 100644
--- a/coreutils/readlink.c
+++ b/coreutils/readlink.c
@@ -36,7 +36,6 @@ int readlink_main(int argc UNUSED_PARAM, char **argv)
 {
         char *buf;
         char *fname;
-        char pathbuf[PATH_MAX];
 
         IF_FEATURE_READLINK_FOLLOW(
                 unsigned opt;
@@ -56,7 +55,7 @@ int readlink_main(int argc UNUSED_PARAM, char **argv)
                 logmode = LOGMODE_NONE;
 
         if (opt & 1) { /* -f */
-                buf = realpath(fname, pathbuf);
+                buf = xmalloc_realpath(fname);
         } else {
                 buf = xmalloc_readlink_or_warn(fname);
         }
@@ -65,7 +64,7 @@ int readlink_main(int argc UNUSED_PARAM, char **argv)
                 return EXIT_FAILURE;
         printf((opt & 2) ? "%s" : "%s\n", buf);
 
-        if (ENABLE_FEATURE_CLEAN_UP && !opt)
+        if (ENABLE_FEATURE_CLEAN_UP)
                 free(buf);
 
         fflush_stdout_and_exit(EXIT_SUCCESS);