pseduo patches are usually sent to the yocto list so
I've added that list and only BCCed oe-core here so
people know where to look for follow-up.
On 2020-09-25 1:05 p.m., Sakib Sajal wrote:
From: Matt Cowell <[email protected]>
Some symlinks in /proc, such as those under /proc/[pid]/fd,
/proc/[pid]/cwd, and /proc/[pid]/exe that are not real and should not
have readlink called on them. These look like symlinks, but behave like
hardlinks. Readlink does not return actual paths. Previously
pseudo_fix_path would expand files such as /dev/stdin to paths such as
/proc/6680/fd/pipe:[1270830076] which do not exist.
This issue affects:
- deleted files
- deleted directories
- fifos
- sockets
- anon_inodes (epoll, eventfd, inotify, signalfd, timerfd, etc)
Testing:
timed builds before and after applying patch, without significant
measurable difference.
$ bitbake -c compile <image>; time bitbake <image>
installed pseudo on an image and was unable to reproduce the test
on bug report after applying the patch.
There might be a better test so please let Sakib know if so.
Sakib,
If there's a v2 or in future work, please give the actual results
such as:
5 trials with an average time of 18m:14s and a range of 22 seconds
on a build host that no one else was using.
This will help people to understand what you mean by
"without significant measurable difference.
Thanks for testing and sending this change.
../Randy
FIXES: Bug 13288
Signed-off-by: Sakib Sajal <[email protected]>
---
pseudo_util.c | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)
diff --git a/pseudo_util.c b/pseudo_util.c
index c867ed6..bce4d1e 100644
--- a/pseudo_util.c
+++ b/pseudo_util.c
@@ -21,6 +21,8 @@
#include <sys/time.h>
#include <unistd.h>
#include <limits.h>
+#include <sys/vfs.h>
+#include <linux/magic.h>
/* see the comments below about (*real_regcomp)() */
#include <dlfcn.h>
@@ -29,6 +31,11 @@
#include "pseudo_ipc.h"
#include "pseudo_db.h"
+/* O_PATH is defined in glibc 2.16 and later only */
+#ifndef O_PATH
+#define O_PATH 010000000
+#endif
+
struct pseudo_variables {
char *key;
size_t key_len;
@@ -677,6 +684,26 @@ pseudo_append_element(char *newpath, char *root, size_t
allocated, char **pcurre
*/
if (!leave_this && is_dir) {
int is_link = S_ISLNK(buf->st_mode);
+
+ /* do not expand symlinks in the proc filesystem, since they
may not be real */
+ if (is_link) {
+ struct statfs sfs;
+ int fd;
+
+ /* statfs follows symlinks, so use fstatfs */
+ fd = open(newpath, O_CLOEXEC | O_PATH | O_NOFOLLOW);
+ if (-1 != fd) {
+ if (0 == fstatfs(fd, &sfs) && sfs.f_type ==
PROC_SUPER_MAGIC) {
+ pseudo_debug(PDBGF_PATH | PDBGF_VERBOSE,
+ "pae: '%s' is procfs symlink, not
expanding\n",
+ newpath);
+ is_link = 0;
+ }
+
+ close(fd);
+ }
+ }
+
if (link_recursion >= PSEUDO_MAX_LINK_RECURSION && is_link) {
pseudo_diag("link recursion too deep, not expanding path
'%s'.\n", newpath);
is_link = 0;
--
# Randy MacLeod
# Wind River Linux
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