glibc/nss/tst-nss-test_errno.c
Florian Weimer 9bdf92c79d nss: Protect against errno changes in function lookup (bug 28953)
dlopen may clobber errno.  The nss_test_errno module uses an ELF
constructor to achieve that, but there could be internal errors
during dlopen that cause this, too.  Therefore, the NSS framework
has to guard against such errno clobbers.

__nss_module_get_function is currently the only function that calls
__nss_module_load, so it is sufficient to save and restore errno
around this call.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2022-03-11 08:24:19 +01:00

62 lines
1.7 KiB
C

/* getpwent failure when dlopen clobbers errno (bug 28953).
Copyright (C) 2022 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 <nss.h>
#include <support/check.h>
#include <stdlib.h>
#include <errno.h>
#include <stdbool.h>
#include <pwd.h>
#include <string.h>
static int
do_test (void)
{
__nss_configure_lookup ("passwd", "files test_errno");
errno = 0;
setpwent ();
TEST_COMPARE (errno, 0);
bool root_seen = false;
while (true)
{
errno = 0;
struct passwd *e = getpwent ();
if (e == NULL)
break;
if (strcmp (e->pw_name, "root"))
root_seen = true;
}
TEST_COMPARE (errno, 0);
TEST_VERIFY (root_seen);
errno = 0;
endpwent ();
TEST_COMPARE (errno, 0);
TEST_COMPARE_STRING (getenv ("_nss_test_errno_setpwent"), "yes");
TEST_COMPARE_STRING (getenv ("_nss_test_errno_getpwent_r"), "yes");
TEST_COMPARE_STRING (getenv ("_nss_test_errno_endpwent"), "yes");
return 0;
}
#include <support/test-driver.c>