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authorThomas De Schampheleire <thomas.de.schampheleire@gmail.com>2013-06-21 19:27:56 (GMT)
committer Denys Vlasenko <vda.linux@googlemail.com>2013-06-27 01:44:46 (GMT)
commit879f008a8f890f83a005d0816d259c6157121e5b (patch)
treec04cb9e6376d8eb18e17d19eaa9f8e35ce45a86b
parentd66eb9042dcc6ee274949fb83612cecbbde44a4a (diff)
downloadbusybox-879f008a8f890f83a005d0816d259c6157121e5b.tar.gz
busybox-879f008a8f890f83a005d0816d259c6157121e5b.tar.bz2
lsof: correct check for symbolic link
Busybox lsof used the d_type field of a 'struct dirent' to verify whether the entry is a symbolic link. This field, however, is not portable. On at least one board [1] I have seen, that field is 0, and the check fails even though the entry is a link. The explicit check for a symbolic link is really only needed to skip the default directory entries '.' and '..'. The directory /proc/<pid>/fd/ should not contain anything else but these two and symbolic links. With these assumptions, this patch replaces the explicit link check with a basic check for '.' and '..' (and any hidden file). In the unlikely case that there are other file types, xmalloc_readlink() will return NULL, and we can skip the entry. [1] A MIPS-based board with glibc 2.9, Linux 2.6.32.27. Signed-off-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--procps/lsof.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/procps/lsof.c b/procps/lsof.c
index 7e0ffa4..b0156a5 100644
--- a/procps/lsof.c
+++ b/procps/lsof.c
@@ -61,9 +61,12 @@ int lsof_main(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
d_fd = opendir(name);
if (d_fd) {
while ((entry = readdir(d_fd)) != NULL) {
- if (entry->d_type == DT_LNK) {
- safe_strncpy(name + baseofs, entry->d_name, 10);
- fdlink = xmalloc_readlink(name);
+ /* Skip entries '.' and '..' (and any hidden file) */
+ if (entry->d_name[0] == '.')
+ continue;
+
+ safe_strncpy(name + baseofs, entry->d_name, 10);
+ if ((fdlink = xmalloc_readlink(name)) != NULL) {
printf("%d\t%s\t%s\n", proc->pid, proc->exe, fdlink);
free(fdlink);
}