posix: New function posix_spawn_file_actions_addchdir_np [BZ #17405]

1 files changed, 192 insertions, 0 deletions

diff --git a/posix/tst-spawn-chdir.c b/posix/tst-spawn-chdir.c
new file mode 100644
index 0000000000..dc14f2059b
--- /dev/null
+++ b/posix/tst-spawn-chdir.c
@@ -0,0 +1,192 @@
+/* Test the posix_spawn_file_actions_addchdir_np function.
+   Copyright (C) 2018 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <array_length.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <spawn.h>
+#include <stdlib.h>
+#include <string.h>
+#include <support/check.h>
+#include <support/support.h>
+#include <support/temp_file.h>
+#include <support/xstdio.h>
+#include <support/xunistd.h>
+#include <unistd.h>
+
+/* Reads the file at PATH, which must consist of exactly one line.
+   Removes the line terminator at the end of the file.  */
+static char *
+read_one_line (const char *path)
+{
+  FILE *fp = xfopen (path, "r");
+  char *buffer = NULL;
+  size_t length = 0;
+  ssize_t ret = getline (&buffer, &length, fp);
+  if (ferror (fp))
+    FAIL_EXIT1 ("getline: %m");
+  if (ret < 1)
+    FAIL_EXIT1 ("getline returned %zd", ret);
+  if (fgetc (fp) != EOF)
+    FAIL_EXIT1 ("trailing bytes in %s", path);
+  if (ferror (fp))
+    FAIL_EXIT1 ("fgetc: %m");
+  xfclose (fp);
+  if (buffer[ret - 1] != '\n')
+    FAIL_EXIT1 ("missing line terminator in %s", path);
+  buffer[ret - 1] = 0;
+  return buffer;
+}
+
+/* Return the path to the "pwd" program.  */
+const char *
+get_pwd_program (void)
+{
+  const char *const paths[] = { "/bin/pwd", "/usr/bin/pwd" };
+  for (size_t i = 0; i < array_length (paths); ++i)
+    if (access (paths[i], X_OK) == 0)
+      return paths[i];
+  FAIL_EXIT1 ("cannot find pwd program");
+}
+
+static int
+do_test (void)
+{
+  /* Directory for temporary file data.  Each subtest uses a numeric
+     subdirectory.  */
+  char *directory = support_create_temp_directory ("tst-spawn-chdir-");
+  {
+    /* Avoid symbolic links, to get more consistent behavior from the
+       pwd command.  */
+    char *tmp = realpath (directory, NULL);
+    if (tmp == NULL)
+      FAIL_EXIT1 ("realpath: %m");
+    free (directory);
+    directory = tmp;
+  }
+
+  char *original_cwd = get_current_dir_name ();
+  if (original_cwd == NULL)
+    FAIL_EXIT1 ("get_current_dir_name: %m");
+
+  int iteration = 0;
+  for (int do_spawnp = 0; do_spawnp < 2; ++do_spawnp)
+    for (int do_overwrite = 0; do_overwrite < 2; ++do_overwrite)
+      {
+        ++iteration;
+        printf ("info: iteration=%d do_spawnp=%d do_overwrite=%d\n",
+                iteration, do_spawnp, do_overwrite);
+
+        /* The "pwd" program runs in this directory.  */
+        char *iteration_directory = xasprintf ("%s/%d", directory, iteration);
+        add_temp_file (iteration_directory);
+        xmkdir (iteration_directory, 0777);
+
+        /* This file receives output from "pwd".  */
+        char *output_file_path
+          = xasprintf ("%s/output-file", iteration_directory);
+        add_temp_file (output_file_path);
+
+        /* This subdirectory is used for chdir ordering checks.  */
+        char *subdir_path = xasprintf ("%s/subdir", iteration_directory);
+        add_temp_file (subdir_path);
+        xmkdir (subdir_path, 0777);
+
+        /* Also used for checking the order of actions.  */
+        char *probe_file_path
+          = xasprintf ("%s/subdir/probe-file", iteration_directory);
+        add_temp_file (probe_file_path);
+        TEST_COMPARE (access (probe_file_path, F_OK), -1);
+        TEST_COMPARE (errno, ENOENT);
+
+        /* This symbolic link is used in a relative path with
+           posix_spawn.  */
+        char *pwd_symlink_path
+          = xasprintf ("%s/subdir/pwd-symlink", iteration_directory);
+        xsymlink (get_pwd_program (), pwd_symlink_path);
+        add_temp_file (pwd_symlink_path);
+
+        posix_spawn_file_actions_t actions;
+        TEST_COMPARE (posix_spawn_file_actions_init (&actions), 0);
+        TEST_COMPARE (posix_spawn_file_actions_addchdir_np
+                      (&actions, subdir_path), 0);
+        TEST_COMPARE (posix_spawn_file_actions_addopen
+                      (&actions, 3, /* Arbitrary unused descriptor.  */
+                       "probe-file",
+                       O_WRONLY | O_CREAT | O_EXCL, 0777), 0);
+        TEST_COMPARE (posix_spawn_file_actions_addclose (&actions, 3), 0);
+        /* Run the actual in iteration_directory.  */
+        TEST_COMPARE (posix_spawn_file_actions_addchdir_np (&actions, ".."), 0);
+        TEST_COMPARE (posix_spawn_file_actions_addopen
+                      (&actions, STDOUT_FILENO, "output-file",
+                       O_WRONLY | O_CREAT | O_EXCL, 0777), 0);
+
+        /* Check that posix_spawn_file_actions_addchdir_np made a copy
+           of the path.  */
+        if (do_overwrite)
+          subdir_path[0] = '\0';
+
+        char *const argv[] = { (char *) "pwd", NULL };
+        char *const envp[] = { NULL } ;
+        pid_t pid;
+        if (do_spawnp)
+          TEST_COMPARE (posix_spawnp (&pid, "pwd", &actions,
+                                      NULL, argv, envp), 0);
+        else
+          TEST_COMPARE (posix_spawn (&pid, "subdir/pwd-symlink", &actions,
+                                     NULL, argv, envp), 0);
+        TEST_VERIFY (pid > 0);
+        int status;
+        xwaitpid (pid, &status, 0);
+        TEST_COMPARE (status, 0);
+
+        /* Check that the current directory did not change.  */
+        {
+          char *cwd = get_current_dir_name ();
+          if (cwd == NULL)
+            FAIL_EXIT1 ("get_current_dir_name: %m");
+          TEST_COMPARE_BLOB (original_cwd, strlen (original_cwd),
+                             cwd, strlen (cwd));
+          free (cwd);
+        }
+
+
+        /* Check the output from "pwd".  */
+        {
+          char *pwd = read_one_line (output_file_path);
+          TEST_COMPARE_BLOB (iteration_directory, strlen (iteration_directory),
+                             pwd, strlen (pwd));
+          free (pwd);
+        }
+
+        /* This file must now exist.  */
+        TEST_COMPARE (access (probe_file_path, F_OK), 0);
+
+        TEST_COMPARE (posix_spawn_file_actions_destroy (&actions), 0);
+        free (pwd_symlink_path);
+        free (probe_file_path);
+        free (subdir_path);
+        free (output_file_path);
+      }
+
+  free (directory);
+
+  return 0;
+}
+
+#include <support/test-driver.c>