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// SPDX-License-Identifier: GPL-2.0-or-later
#define _GNU_SOURCE
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <syscall.h>
#include <unistd.h>
#include "../kselftest.h"
int sys_fchmodat2(int dfd, const char *filename, mode_t mode, int flags)
{
int ret = syscall(__NR_fchmodat2, dfd, filename, mode, flags);
return ret >= 0 ? ret : -errno;
}
int setup_testdir(void)
{
int dfd, ret;
char dirname[] = "/tmp/ksft-fchmodat2.XXXXXX";
/* Make the top-level directory. */
if (!mkdtemp(dirname))
ksft_exit_fail_msg("%s: failed to create tmpdir\n", __func__);
dfd = open(dirname, O_PATH | O_DIRECTORY);
if (dfd < 0)
ksft_exit_fail_msg("%s: failed to open tmpdir\n", __func__);
ret = openat(dfd, "regfile", O_CREAT | O_WRONLY | O_TRUNC, 0644);
if (ret < 0)
ksft_exit_fail_msg("%s: failed to create file in tmpdir\n",
__func__);
close(ret);
ret = symlinkat("regfile", dfd, "symlink");
if (ret < 0)
ksft_exit_fail_msg("%s: failed to create symlink in tmpdir\n",
__func__);
return dfd;
}
int expect_mode(int dfd, const char *filename, mode_t expect_mode)
{
struct stat st;
int ret = fstatat(dfd, filename, &st, AT_SYMLINK_NOFOLLOW);
if (ret)
ksft_exit_fail_msg("%s: %s: fstatat failed\n",
__func__, filename);
return (st.st_mode == expect_mode);
}
void test_regfile(void)
{
int dfd, ret;
dfd = setup_testdir();
ret = sys_fchmodat2(dfd, "regfile", 0640, 0);
if (ret < 0)
ksft_exit_fail_msg("%s: fchmodat2(noflag) failed\n", __func__);
if (!expect_mode(dfd, "regfile", 0100640))
ksft_exit_fail_msg("%s: wrong file mode bits after fchmodat2\n",
__func__);
ret = sys_fchmodat2(dfd, "regfile", 0600, AT_SYMLINK_NOFOLLOW);
if (ret < 0)
ksft_exit_fail_msg("%s: fchmodat2(AT_SYMLINK_NOFOLLOW) failed\n",
__func__);
if (!expect_mode(dfd, "regfile", 0100600))
ksft_exit_fail_msg("%s: wrong file mode bits after fchmodat2 with nofollow\n",
__func__);
ksft_test_result_pass("fchmodat2(regfile)\n");
}
void test_symlink(void)
{
int dfd, ret;
dfd = setup_testdir();
ret = sys_fchmodat2(dfd, "symlink", 0640, 0);
if (ret < 0)
ksft_exit_fail_msg("%s: fchmodat2(noflag) failed\n", __func__);
if (!expect_mode(dfd, "regfile", 0100640))
ksft_exit_fail_msg("%s: wrong file mode bits after fchmodat2\n",
__func__);
if (!expect_mode(dfd, "symlink", 0120777))
ksft_exit_fail_msg("%s: wrong symlink mode bits after fchmodat2\n",
__func__);
ret = sys_fchmodat2(dfd, "symlink", 0600, AT_SYMLINK_NOFOLLOW);
/*
* On certain filesystems (xfs or btrfs), chmod operation fails. So we
* first check the symlink target but if the operation fails we mark the
* test as skipped.
*
* https://sourceware.org/legacy-ml/libc-alpha/2020-02/msg00467.html
*/
if (ret == 0 && !expect_mode(dfd, "symlink", 0120600))
ksft_exit_fail_msg("%s: wrong symlink mode bits after fchmodat2 with nofollow\n",
__func__);
if (!expect_mode(dfd, "regfile", 0100640))
ksft_exit_fail_msg("%s: wrong file mode bits after fchmodat2 with nofollow\n",
__func__);
if (ret != 0)
ksft_test_result_skip("fchmodat2(symlink)\n");
else
ksft_test_result_pass("fchmodat2(symlink)\n");
}
#define NUM_TESTS 2
int main(int argc, char **argv)
{
ksft_print_header();
ksft_set_plan(NUM_TESTS);
test_regfile();
test_symlink();
if (ksft_get_fail_cnt() + ksft_get_error_cnt() > 0)
ksft_exit_fail();
else
ksft_exit_pass();
}
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