Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0-or-later
2
3#define _GNU_SOURCE
4#include <fcntl.h>
5#include <sys/stat.h>
6#include <sys/types.h>
7#include <syscall.h>
8#include <unistd.h>
9
10#include "kselftest.h"
11
12struct testdir {
13 char *dirname;
14 int dfd;
15};
16
17int sys_fchmodat2(int dfd, const char *filename, mode_t mode, int flags)
18{
19 int ret = syscall(__NR_fchmodat2, dfd, filename, mode, flags);
20
21 return ret >= 0 ? ret : -errno;
22}
23
24static void setup_testdir(struct testdir *testdir)
25{
26 int ret, dfd;
27 char dirname[] = "/tmp/ksft-fchmodat2.XXXXXX";
28
29 /* Make the top-level directory. */
30 if (!mkdtemp(dirname))
31 ksft_exit_fail_msg("%s: failed to create tmpdir\n", __func__);
32
33 dfd = open(dirname, O_PATH | O_DIRECTORY);
34 if (dfd < 0) {
35 ksft_perror("failed to open tmpdir");
36 goto err;
37 }
38
39 ret = openat(dfd, "regfile", O_CREAT | O_WRONLY | O_TRUNC, 0644);
40 if (ret < 0) {
41 ksft_perror("failed to create file in tmpdir");
42 goto err;
43 }
44 close(ret);
45
46 ret = symlinkat("regfile", dfd, "symlink");
47 if (ret < 0) {
48 ksft_perror("symlinkat() failed");
49 goto err_regfile;
50 }
51
52 testdir->dirname = strdup(dirname);
53 if (!testdir->dirname) {
54 ksft_perror("Out of memory");
55 goto err_symlink;
56 }
57 testdir->dfd = dfd;
58
59 return;
60
61err_symlink:
62 unlinkat(testdir->dfd, "symlink", 0);
63err_regfile:
64 unlinkat(testdir->dfd, "regfile", 0);
65err:
66 unlink(dirname);
67 ksft_exit_fail();
68}
69
70static void cleanup_testdir(struct testdir *testdir)
71{
72 unlinkat(testdir->dfd, "regfile", 0);
73 unlinkat(testdir->dfd, "symlink", 0);
74 rmdir(testdir->dirname);
75 free(testdir->dirname);
76}
77
78int expect_mode(int dfd, const char *filename, mode_t expect_mode)
79{
80 struct stat st;
81 int ret = fstatat(dfd, filename, &st, AT_SYMLINK_NOFOLLOW);
82
83 if (ret) {
84 ksft_perror("fstatat() failed\n");
85 return 0;
86 }
87
88 return (st.st_mode == expect_mode);
89}
90
91void test_regfile(void)
92{
93 struct testdir testdir;
94 int ret;
95
96 setup_testdir(&testdir);
97
98 ret = sys_fchmodat2(testdir.dfd, "regfile", 0640, 0);
99
100 if (ret < 0) {
101 ksft_perror("fchmodat2(noflag) failed");
102 goto out;
103 }
104
105 if (!expect_mode(testdir.dfd, "regfile", 0100640)) {
106 ksft_print_msg("%s: wrong file mode bits after fchmodat2\n",
107 __func__);
108 ret = 1;
109 goto out;
110 }
111
112 ret = sys_fchmodat2(testdir.dfd, "regfile", 0600, AT_SYMLINK_NOFOLLOW);
113
114 if (ret < 0) {
115 ksft_perror("fchmodat2(AT_SYMLINK_NOFOLLOW) failed");
116 goto out;
117 }
118
119 if (!expect_mode(testdir.dfd, "regfile", 0100600)) {
120 ksft_print_msg("%s: wrong file mode bits after fchmodat2 with nofollow\n",
121 __func__);
122 ret = 1;
123 }
124
125out:
126 ksft_test_result(ret == 0, "fchmodat2(regfile)\n");
127 cleanup_testdir(&testdir);
128}
129
130void test_symlink(void)
131{
132 struct testdir testdir;
133 int ret;
134
135 setup_testdir(&testdir);
136
137 ret = sys_fchmodat2(testdir.dfd, "symlink", 0640, 0);
138
139 if (ret < 0) {
140 ksft_perror("fchmodat2(noflag) failed");
141 goto err;
142 }
143
144 if (!expect_mode(testdir.dfd, "regfile", 0100640)) {
145 ksft_print_msg("%s: wrong file mode bits after fchmodat2\n",
146 __func__);
147 goto err;
148 }
149
150 if (!expect_mode(testdir.dfd, "symlink", 0120777)) {
151 ksft_print_msg("%s: wrong symlink mode bits after fchmodat2\n",
152 __func__);
153 goto err;
154 }
155
156 ret = sys_fchmodat2(testdir.dfd, "symlink", 0600, AT_SYMLINK_NOFOLLOW);
157
158 /*
159 * On certain filesystems (xfs or btrfs), chmod operation fails. So we
160 * first check the symlink target but if the operation fails we mark the
161 * test as skipped.
162 *
163 * https://sourceware.org/legacy-ml/libc-alpha/2020-02/msg00467.html
164 */
165 if (ret == 0 && !expect_mode(testdir.dfd, "symlink", 0120600)) {
166 ksft_print_msg("%s: wrong symlink mode bits after fchmodat2 with nofollow\n",
167 __func__);
168 ret = 1;
169 goto err;
170 }
171
172 if (!expect_mode(testdir.dfd, "regfile", 0100640)) {
173 ksft_print_msg("%s: wrong file mode bits after fchmodat2 with nofollow\n",
174 __func__);
175 }
176
177 if (ret != 0)
178 ksft_test_result_skip("fchmodat2(symlink)\n");
179 else
180 ksft_test_result_pass("fchmodat2(symlink)\n");
181 cleanup_testdir(&testdir);
182 return;
183
184err:
185 ksft_test_result_fail("fchmodat2(symlink)\n");
186 cleanup_testdir(&testdir);
187}
188
189#define NUM_TESTS 2
190
191int main(int argc, char **argv)
192{
193 ksft_print_header();
194 ksft_set_plan(NUM_TESTS);
195
196 test_regfile();
197 test_symlink();
198
199 ksft_finished();
200}