Avoid uninitialized result in sem_open when file does not exist

A static analyzer apparently reported an uninitialized use of the
variable result in sem_open in the case where the file is required to
exist but does not exist.

The report appears to be correct; set result to SEM_FAILED in that
case, and add a test for it.

Note: the test passes for me even without the sem_open fix, I guess
because result happens to get value SEM_FAILED (i.e. 0) when
uninitialized.

Tested for x86_64.
This commit is contained in:
Joseph Myers 2024-11-08 01:53:48 +00:00
parent 97f60abd25
commit f745d78e26
3 changed files with 37 additions and 0 deletions

View File

@ -256,6 +256,7 @@ tests += \
tst-sem14 \
tst-sem15 \
tst-sem16 \
tst-sem17 \
tst-setuid3 \
tst-signal1 \
tst-signal2 \

View File

@ -76,6 +76,7 @@ __sem_open (const char *name, int oflag, ...)
goto try_create;
/* Return. errno is already set. */
result = SEM_FAILED;
}
else
/* Check whether we already have this semaphore mapped and

View File

@ -0,0 +1,35 @@
/* Test sem_open with missing file.
Copyright (C) 2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <errno.h>
#include <semaphore.h>
#include <support/check.h>
int
do_test (void)
{
sem_unlink ("/glibc-tst-sem17");
errno = 0;
sem_t *s = sem_open ("/glibc-tst-sem17", 0);
TEST_VERIFY (s == SEM_FAILED);
TEST_COMPARE (errno, ENOENT);
return 0;
}
#include <support/test-driver.c>