tools/testing/selftests/fchmodat2/fchmodat2_test.c

   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
  12 int sys_fchmodat2(int dfd, const char *filename, mode_t mode, int flags)
  13 {
  14         int ret = syscall(__NR_fchmodat2, dfd, filename, mode, flags);
  15
  16         return ret >= 0 ? ret : -errno;
  17 }
  18
  19 int setup_testdir(void)
  20 {
  21         int dfd, ret;
  22         char dirname[] = "/tmp/ksft-fchmodat2.XXXXXX";
  23
  24         /* Make the top-level directory. */
  25         if (!mkdtemp(dirname))
  26                 ksft_exit_fail_msg("%s: failed to create tmpdir\n", __func__);
  27
  28         dfd = open(dirname, O_PATH | O_DIRECTORY);
  29         if (dfd < 0)
  30                 ksft_exit_fail_msg("%s: failed to open tmpdir\n", __func__);
  31
  32         ret = openat(dfd, "regfile", O_CREAT | O_WRONLY | O_TRUNC, 0644);
  33         if (ret < 0)
  34                 ksft_exit_fail_msg("%s: failed to create file in tmpdir\n",
  35                                 __func__);
  36         close(ret);
  37
  38         ret = symlinkat("regfile", dfd, "symlink");
  39         if (ret < 0)
  40                 ksft_exit_fail_msg("%s: failed to create symlink in tmpdir\n",
  41                                 __func__);
  42
  43         return dfd;
  44 }
  45
  46 int expect_mode(int dfd, const char *filename, mode_t expect_mode)
  47 {
  48         struct stat st;
  49         int ret = fstatat(dfd, filename, &st, AT_SYMLINK_NOFOLLOW);
  50
  51         if (ret)
  52                 ksft_exit_fail_msg("%s: %s: fstatat failed\n",
  53                                 __func__, filename);
  54
  55         return (st.st_mode == expect_mode);
  56 }
  57
  58 void test_regfile(void)
  59 {
  60         int dfd, ret;
  61
  62         dfd = setup_testdir();
  63
  64         ret = sys_fchmodat2(dfd, "regfile", 0640, 0);
  65
  66         if (ret < 0)
  67                 ksft_exit_fail_msg("%s: fchmodat2(noflag) failed\n", __func__);
  68
  69         if (!expect_mode(dfd, "regfile", 0100640))
  70                 ksft_exit_fail_msg("%s: wrong file mode bits after fchmodat2\n",
  71                                 __func__);
  72
  73         ret = sys_fchmodat2(dfd, "regfile", 0600, AT_SYMLINK_NOFOLLOW);
  74
  75         if (ret < 0)
  76                 ksft_exit_fail_msg("%s: fchmodat2(AT_SYMLINK_NOFOLLOW) failed\n",
  77                                 __func__);
  78
  79         if (!expect_mode(dfd, "regfile", 0100600))
  80                 ksft_exit_fail_msg("%s: wrong file mode bits after fchmodat2 with nofollow\n",
  81                                 __func__);
  82
  83         ksft_test_result_pass("fchmodat2(regfile)\n");
  84 }
  85
  86 void test_symlink(void)
  87 {
  88         int dfd, ret;
  89
  90         dfd = setup_testdir();
  91
  92         ret = sys_fchmodat2(dfd, "symlink", 0640, 0);
  93
  94         if (ret < 0)
  95                 ksft_exit_fail_msg("%s: fchmodat2(noflag) failed\n", __func__);
  96
  97         if (!expect_mode(dfd, "regfile", 0100640))
  98                 ksft_exit_fail_msg("%s: wrong file mode bits after fchmodat2\n",
  99                                 __func__);
 100
 101         if (!expect_mode(dfd, "symlink", 0120777))
 102                 ksft_exit_fail_msg("%s: wrong symlink mode bits after fchmodat2\n",
 103                                 __func__);
 104
 105         ret = sys_fchmodat2(dfd, "symlink", 0600, AT_SYMLINK_NOFOLLOW);
 106
 107         /*
 108          * On certain filesystems (xfs or btrfs), chmod operation fails. So we
 109          * first check the symlink target but if the operation fails we mark the
 110          * test as skipped.
 111          *
 112          * https://sourceware.org/legacy-ml/libc-alpha/2020-02/msg00467.html
 113          */
 114         if (ret == 0 && !expect_mode(dfd, "symlink", 0120600))
 115                 ksft_exit_fail_msg("%s: wrong symlink mode bits after fchmodat2 with nofollow\n",
 116                                 __func__);
 117
 118         if (!expect_mode(dfd, "regfile", 0100640))
 119                 ksft_exit_fail_msg("%s: wrong file mode bits after fchmodat2 with nofollow\n",
 120                                 __func__);
 121
 122         if (ret != 0)
 123                 ksft_test_result_skip("fchmodat2(symlink)\n");
 124         else
 125                 ksft_test_result_pass("fchmodat2(symlink)\n");
 126 }
 127
 128 #define NUM_TESTS 2
 129
 130 int main(int argc, char **argv)
 131 {
 132         ksft_print_header();
 133         ksft_set_plan(NUM_TESTS);
 134
 135         test_regfile();
 136         test_symlink();
 137
 138         if (ksft_get_fail_cnt() + ksft_get_error_cnt() > 0)
 139                 ksft_exit_fail();
 140         else
 141                 ksft_exit_pass();
 142 }