posix/tst-spawn-chdir.c

   1 /* Test the posix_spawn_file_actions_addchdir_np function.
   2    Copyright (C) 2018-2022 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <array_length.h>
  20 #include <errno.h>
  21 #include <fcntl.h>
  22 #include <spawn.h>
  23 #include <stdbool.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <support/check.h>
  27 #include <support/support.h>
  28 #include <support/temp_file.h>
  29 #include <support/test-driver.h>
  30 #include <support/xstdio.h>
  31 #include <support/xunistd.h>
  32 #include <unistd.h>
  33
  34 /* Reads the file at PATH, which must consist of exactly one line.
  35    Removes the line terminator at the end of the file.  */
  36 static char *
  37 read_one_line (const char *path)
  38 {
  39   FILE *fp = xfopen (path, "r");
  40   char *buffer = NULL;
  41   size_t length = 0;
  42   ssize_t ret = getline (&buffer, &length, fp);
  43   if (ferror (fp))
  44     FAIL_EXIT1 ("getline: %m");
  45   if (ret < 1)
  46     FAIL_EXIT1 ("getline returned %zd", ret);
  47   if (fgetc (fp) != EOF)
  48     FAIL_EXIT1 ("trailing bytes in %s", path);
  49   if (ferror (fp))
  50     FAIL_EXIT1 ("fgetc: %m");
  51   xfclose (fp);
  52   if (buffer[ret - 1] != '\n')
  53     FAIL_EXIT1 ("missing line terminator in %s", path);
  54   buffer[ret - 1] = 0;
  55   return buffer;
  56 }
  57
  58 /* Return the path to the "pwd" program.  */
  59 const char *
  60 get_pwd_program (void)
  61 {
  62   const char *const paths[] = { "/bin/pwd", "/usr/bin/pwd" };
  63   for (size_t i = 0; i < array_length (paths); ++i)
  64     if (access (paths[i], X_OK) == 0)
  65       return paths[i];
  66   FAIL_EXIT1 ("cannot find pwd program");
  67 }
  68
  69 /* Adds chdir operations to ACTIONS, using PATH.  If DO_FCHDIR, use
  70    the open function and TMPFD to emulate chdir using fchdir.  */
  71 static void
  72 add_chdir (posix_spawn_file_actions_t *actions, const char *path,
  73            bool do_fchdir, int tmpfd)
  74 {
  75   if (do_fchdir)
  76     {
  77       TEST_COMPARE (posix_spawn_file_actions_addopen
  78                     (actions, tmpfd, path, O_DIRECTORY | O_RDONLY, 0), 0);
  79       TEST_COMPARE (posix_spawn_file_actions_addfchdir_np
  80                     (actions, tmpfd), 0);
  81       TEST_COMPARE (posix_spawn_file_actions_addclose (actions, tmpfd), 0);
  82     }
  83   else
  84     TEST_COMPARE (posix_spawn_file_actions_addchdir_np (actions, path), 0);
  85 }
  86
  87 static int
  88 do_test (void)
  89 {
  90   /* Directory for temporary file data.  Each subtest uses a numeric
  91      subdirectory.  */
  92   char *directory = support_create_temp_directory ("tst-spawn-chdir-");
  93   {
  94     /* Avoid symbolic links, to get more consistent behavior from the
  95        pwd command.  */
  96     char *tmp = realpath (directory, NULL);
  97     if (tmp == NULL)
  98       FAIL_EXIT1 ("realpath: %m");
  99     free (directory);
 100     directory = tmp;
 101   }
 102
 103   char *original_cwd = get_current_dir_name ();
 104   if (original_cwd == NULL)
 105     FAIL_EXIT1 ("get_current_dir_name: %m");
 106
 107   int iteration = 0;
 108   for (int do_spawnp = 0; do_spawnp < 2; ++do_spawnp)
 109     for (int do_overwrite = 0; do_overwrite < 2; ++do_overwrite)
 110       for (int do_fchdir = 0; do_fchdir < 2; ++do_fchdir)
 111         {
 112           /* This subtest does not make sense for fchdir.  */
 113           if (do_overwrite && do_fchdir)
 114             continue;
 115
 116           ++iteration;
 117           if (test_verbose > 0)
 118             printf ("info: iteration=%d do_spawnp=%d do_overwrite=%d"
 119                     " do_fchdir=%d\n",
 120                     iteration, do_spawnp, do_overwrite, do_fchdir);
 121
 122           /* The "pwd" program runs in this directory.  */
 123           char *iteration_directory = xasprintf ("%s/%d", directory, iteration);
 124           add_temp_file (iteration_directory);
 125           xmkdir (iteration_directory, 0777);
 126
 127           /* This file receives output from "pwd".  */
 128           char *output_file_path
 129             = xasprintf ("%s/output-file", iteration_directory);
 130           add_temp_file (output_file_path);
 131
 132           /* This subdirectory is used for chdir ordering checks.  */
 133           char *subdir_path = xasprintf ("%s/subdir", iteration_directory);
 134           add_temp_file (subdir_path);
 135           xmkdir (subdir_path, 0777);
 136
 137           /* Also used for checking the order of actions.  */
 138           char *probe_file_path
 139             = xasprintf ("%s/subdir/probe-file", iteration_directory);
 140           add_temp_file (probe_file_path);
 141           TEST_COMPARE (access (probe_file_path, F_OK), -1);
 142           TEST_COMPARE (errno, ENOENT);
 143
 144           /* This symbolic link is used in a relative path with
 145              posix_spawn.  */
 146           char *pwd_symlink_path
 147             = xasprintf ("%s/subdir/pwd-symlink", iteration_directory);
 148           xsymlink (get_pwd_program (), pwd_symlink_path);
 149           add_temp_file (pwd_symlink_path);
 150
 151           posix_spawn_file_actions_t actions;
 152           TEST_COMPARE (posix_spawn_file_actions_init (&actions), 0);
 153           add_chdir (&actions, subdir_path, do_fchdir, 4);
 154           TEST_COMPARE (posix_spawn_file_actions_addopen
 155                         (&actions, 3, /* Arbitrary unused descriptor.  */
 156                          "probe-file",
 157                          O_WRONLY | O_CREAT | O_EXCL, 0777), 0);
 158           TEST_COMPARE (posix_spawn_file_actions_addclose (&actions, 3), 0);
 159           /* Run the actual in iteration_directory.  */
 160           add_chdir (&actions, "..", do_fchdir, 5);
 161           TEST_COMPARE (posix_spawn_file_actions_addopen
 162                         (&actions, STDOUT_FILENO, "output-file",
 163                          O_WRONLY | O_CREAT | O_EXCL, 0777), 0);
 164
 165           /* Check that posix_spawn_file_actions_addchdir_np made a copy
 166              of the path.  */
 167           if (do_overwrite)
 168             subdir_path[0] = '\0';
 169
 170           char *const argv[] = { (char *) "pwd", NULL };
 171           char *const envp[] = { NULL } ;
 172           pid_t pid;
 173           if (do_spawnp)
 174             TEST_COMPARE (posix_spawnp (&pid, "pwd", &actions,
 175                                         NULL, argv, envp), 0);
 176           else
 177             TEST_COMPARE (posix_spawn (&pid, "subdir/pwd-symlink", &actions,
 178                                        NULL, argv, envp), 0);
 179           TEST_VERIFY (pid > 0);
 180           int status;
 181           xwaitpid (pid, &status, 0);
 182           TEST_COMPARE (status, 0);
 183
 184           /* Check that the current directory did not change.  */
 185           {
 186             char *cwd = get_current_dir_name ();
 187             if (cwd == NULL)
 188               FAIL_EXIT1 ("get_current_dir_name: %m");
 189             TEST_COMPARE_BLOB (original_cwd, strlen (original_cwd),
 190                                cwd, strlen (cwd));
 191             free (cwd);
 192           }
 193
 194
 195           /* Check the output from "pwd".  */
 196           {
 197             char *pwd = read_one_line (output_file_path);
 198             TEST_COMPARE_BLOB (iteration_directory, strlen (iteration_directory),
 199                                pwd, strlen (pwd));
 200             free (pwd);
 201           }
 202
 203           /* This file must now exist.  */
 204           TEST_COMPARE (access (probe_file_path, F_OK), 0);
 205
 206           TEST_COMPARE (posix_spawn_file_actions_destroy (&actions), 0);
 207           free (pwd_symlink_path);
 208           free (probe_file_path);
 209           free (subdir_path);
 210           free (output_file_path);
 211         }
 212
 213   free (directory);
 214
 215   return 0;
 216 }
 217
 218 #include <support/test-driver.c>