The test posix/tst-glob_symlinks.c fails to build with GCC mainline:
tst-glob_symlinks.c: In function 'do_test':
tst-glob_symlinks.c:124:30: error: 'snprintf' output may be truncated before the last format character [-Werror=format-truncation=]
snprintf (buf, sizeof buf, "%s?", dangling_link);
^~~~~
tst-glob_symlinks.c:124:3: note: 'snprintf' output between 2 and 4097 bytes into a destination of size 4096
snprintf (buf, sizeof buf, "%s?", dangling_link);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
tst-glob_symlinks.c:128:30: error: 'snprintf' output may be truncated before the last format character [-Werror=format-truncation=]
snprintf (buf, sizeof buf, "%s*", dangling_link);
^~~~~
tst-glob_symlinks.c:128:3: note: 'snprintf' output between 2 and 4097 bytes into a destination of size 4096
snprintf (buf, sizeof buf, "%s*", dangling_link);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This patch fixes the test to avoid such truncation warnings by
increasing the buffer in question by one byte, to ensure it can hold
any possible result of %s? or %s* formats where %s comes from a buffer
of size PATH_MAX.
Tested compilation with build-many-glibcs.py for aarch64-linux-gnu.
* posix/tst-glob_symlinks.c (do_test): Increase size of buf.
This patch makes glob match dangling symlinks. Compared to other glob
implementation (*BSD, bash, musl, and other shells as well), GLIBC seems
the be the only one that does not match dangling symlinks. As for
comment #5 in BZ #866, POSIX does not have any strict specification for
dangling symlinks match and it is reasonable that trying to glob everything
in a path should return all types of files (such as for a 'rm *'). Also,
comment #7 shows even more example where GLIBC current behavior is
unexepected.
I avoided adding another GNU specific flag to set this behavior and
instead make it the default. Although this change the semanthic from
previous implementation, I think adding another compat symbol to be
really unecessary as from aforementioned reasons (current behavior not
defined in any standard, general idea of different implementation is
to list dangling symbols).
This also sync glob with gnulib commit fd1daf4 (glob: match dangling
symlinks).
Checked on x86_64-linux-gnu and on a build using build-many-glibcs.py
for all major architectures.
[BZ #866]
[BZ #1062]
* posix/Makefile (tests): Remove bug-glob1 and tst-glob_symlinks.
* posix/bug-glob1.c: Remove file.
* posix/tst-glob_symlinks.c: New file.
* posix/glob.c (__lstat64): New macro.
(is_dir): New function.
(glob, glob_in_dir): Match symlinks even if they are dangling.
(link_stat, link_exists_p): Remove. All uses removed.
Joseph Myers
Samuel Thibault
Adhemerval Zanella