I found this problem while looking into Bug#13516
<http://bugs.gnu.org/13515>. Currently, the openat
emulator exits the program if savedir fails, but it's
nicer if it merely causes openat to fail. If savedir
fails, no harm has been done yet -- the program's
working directory has not changed, so there's no need
to do something as drastic as exit the program.
Here's a proposed patch. It also fixes some more-obscure
issues in functions like linkat. I suppose I could pull
them out as a separate patch but I'm not sure it's worth
the trouble.
openat: don't exit program if save_cwd fails
* lib/at-func.c (AT_FUNC_NAME):
* lib/at-func2.c (at_func2):
* lib/openat.c (openat_permissive):
If save_cwd fails, simply return a failure rather than exiting the
program. No harm has been done yet, since we haven't used chdir.
* lib/at-func2.c (at_func2): Simplify, and fix bugs whereby the
code would leave the application in the wrong directory (!) in
some tricky failure cases.
diff --git a/lib/at-func.c b/lib/at-func.c
index 03c5678..aa94561 100644
--- a/lib/at-func.c
+++ b/lib/at-func.c
@@ -108,7 +108,7 @@ AT_FUNC_NAME (int fd, char const *file
AT_FUNC_POST_FILE_PARAM_DECLS)
}
if (save_cwd (&saved_cwd) != 0)
- openat_save_fail (errno);
+ return FUNC_FAIL;
if (0 <= fd && fd == saved_cwd.desc)
{
/* If saving the working directory collides with the user's
diff --git a/lib/at-func2.c b/lib/at-func2.c
index bbbddc0..169d886 100644
--- a/lib/at-func2.c
+++ b/lib/at-func2.c
@@ -180,7 +180,7 @@ at_func2 (int fd1, char const *file1,
place, it is time to start changing directories. */
if (save_cwd (&saved_cwd) != 0)
- openat_save_fail (errno);
+ return -1;
if (fd1 != AT_FDCWD && fd2 != AT_FDCWD && fd1 != fd2) /* Case 15b. */
{
@@ -199,6 +199,7 @@ at_func2 (int fd1, char const *file1,
file1_alt = (char *) file1;
file2_alt = (char *) file2;
+ saved_errno = 0;
if (fd1 == AT_FDCWD && !IS_ABSOLUTE_FILE_NAME (file1)) /* Case 7. */
{
@@ -207,63 +208,41 @@ at_func2 (int fd1, char const *file1,
but libraries should not call xalloc_die. */
char *cwd = getcwd (NULL, 0);
if (!cwd)
+ saved_errno = errno;
+ else
{
- saved_errno = errno;
- free_cwd (&saved_cwd);
- errno = saved_errno;
- return -1;
- }
- file1_alt = mfile_name_concat (cwd, file1, NULL);
- if (!file1_alt)
- {
- saved_errno = errno;
+ file1_alt = mfile_name_concat (cwd, file1, NULL);
+ if (!file1_alt)
+ saved_errno = errno;
free (cwd);
- free_cwd (&saved_cwd);
- errno = saved_errno;
- return -1;
}
- free (cwd); /* Reduced to case 3. */
+ /* Reduced to case 3. */
}
else if (fd2 == AT_FDCWD && !IS_ABSOLUTE_FILE_NAME (file2)) /* Case 13. */
{
char *cwd = getcwd (NULL, 0);
if (!cwd)
+ saved_errno = errno;
+ else
{
- saved_errno = errno;
- free_cwd (&saved_cwd);
- errno = saved_errno;
- return -1;
- }
- file2_alt = mfile_name_concat (cwd, file2, NULL);
- if (!file2_alt)
- {
- saved_errno = errno;
+ file2_alt = mfile_name_concat (cwd, file2, NULL);
+ if (!file2_alt)
+ saved_errno = errno;
free (cwd);
- free_cwd (&saved_cwd);
- errno = saved_errno;
- return -1;
}
- free (cwd); /* Reduced to case 12. */
+ /* Reduced to case 12. */
}
- /* Cases 3, 12, 15a remain. Change to the correct directory. */
- if (fchdir (fd1 == AT_FDCWD ? fd2 : fd1) != 0)
+ err = -1;
+ if (! saved_errno)
{
+ /* Cases 3, 12, 15a remain. Change to the correct directory
+ and perform the user's function. */
+ if (fchdir (fd1 == AT_FDCWD ? fd2 : fd1) == 0)
+ err = func (file1_alt, file2_alt);
saved_errno = errno;
- free_cwd (&saved_cwd);
- if (file1 != file1_alt)
- free (file1_alt);
- else if (file2 != file2_alt)
- free (file2_alt);
- errno = saved_errno;
- return -1;
}
- /* Finally safe to perform the user's function, then clean up. */
-
- err = func (file1_alt, file2_alt);
- saved_errno = (err < 0 ? errno : 0);
-
if (file1 != file1_alt)
free (file1_alt);
else if (file2 != file2_alt)
@@ -274,8 +253,7 @@ at_func2 (int fd1, char const *file1,
free_cwd (&saved_cwd);
- if (saved_errno)
- errno = saved_errno;
+ errno = saved_errno;
return err;
}
#undef CALL_FUNC
diff --git a/lib/openat.c b/lib/openat.c
index fd1ff91..7ea0e58 100644
--- a/lib/openat.c
+++ b/lib/openat.c
@@ -220,7 +220,7 @@ openat_permissive (int fd, char const *file, int flags,
mode_t mode,
if (! save_ok)
{
if (! cwd_errno)
- openat_save_fail (errno);
+ return -1;
*cwd_errno = errno;
}
if (0 <= fd && fd == saved_cwd.desc)
