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/* Test for the memfd_create system call.
Copyright (C) 2017-2024 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 <fcntl.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <support/check.h>
#include <support/support.h>
#include <support/test-driver.h>
#include <support/xunistd.h>
#include <sys/mman.h>
/* Return true if the descriptor has the FD_CLOEXEC flag set. */
static bool
is_cloexec (int fd)
{
int flags = fcntl (fd, F_GETFD);
TEST_VERIFY (flags >= 0);
return flags & FD_CLOEXEC;
}
/* Return the seals set on FD. */
static int
get_seals (int fd)
{
int flags = fcntl (fd, F_GET_SEALS);
TEST_VERIFY (flags >= 0);
return flags;
}
/* Return true if the F_SEAL_SEAL flag is set on the descriptor. */
static bool
is_sealed (int fd)
{
return get_seals (fd) & F_SEAL_SEAL;
}
static int
do_test (void)
{
/* Initialized by the first call to memfd_create to 0 (memfd_create
unsupported) or 1 (memfd_create is implemented in the kernel).
Subsequent iterations check that the success/failure state is
consistent. */
int supported = -1;
for (int do_cloexec = 0; do_cloexec < 2; ++do_cloexec)
for (int do_sealing = 0; do_sealing < 2; ++do_sealing)
{
int flags = 0;
if (do_cloexec)
flags |= MFD_CLOEXEC;
if (do_sealing)
flags |= MFD_ALLOW_SEALING;
if (test_verbose > 0)
printf ("info: memfd_create with flags=0x%x\n", flags);
int fd = memfd_create ("tst-memfd_create", flags);
if (fd < 0)
{
if (errno == ENOSYS)
{
if (supported < 0)
{
printf ("warning: memfd_create is unsupported\n");
supported = 0;
continue;
}
TEST_VERIFY (supported == 0);
continue;
}
else
FAIL_EXIT1 ("memfd_create: %m");
}
if (supported < 0)
supported = 1;
TEST_VERIFY (supported > 0);
char *fd_path = xasprintf ("/proc/self/fd/%d", fd);
char *link = xreadlink (fd_path);
if (test_verbose > 0)
printf ("info: memfd link: %s\n", link);
TEST_VERIFY (strcmp (link, "memfd:tst-memfd_create (deleted)"));
TEST_VERIFY (is_cloexec (fd) == do_cloexec);
TEST_VERIFY (is_sealed (fd) == !do_sealing);
if (do_sealing)
{
TEST_VERIFY (fcntl (fd, F_ADD_SEALS, F_SEAL_WRITE) == 0);
TEST_VERIFY (!is_sealed (fd));
TEST_VERIFY (get_seals (fd) & F_SEAL_WRITE);
TEST_VERIFY (fcntl (fd, F_ADD_SEALS, F_SEAL_SEAL) == 0);
TEST_VERIFY (is_sealed (fd));
}
xclose (fd);
free (fd_path);
free (link);
}
if (supported == 0)
return EXIT_UNSUPPORTED;
return 0;
}
#include <support/test-driver.c>
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