support: Add xstrndup, xunlink, xreadlink, support_create_temp_directory

1 files changed, 72 insertions, 0 deletions

diff --git a/support/tst-xreadlink.c b/support/tst-xreadlink.c
new file mode 100644
index 0000000000..cb2c12a888
--- /dev/null
+++ b/support/tst-xreadlink.c
@@ -0,0 +1,72 @@
+/* Test the xreadlink function.
+   Copyright (C) 2017 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 <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <support/check.h>
+#include <support/support.h>
+#include <support/temp_file.h>
+#include <support/xunistd.h>
+
+static int
+do_test (void)
+{
+  char *dir = support_create_temp_directory ("/tmp/tst-xreadlink-XXXXXX");
+  char *symlink_name = xasprintf ("%s/symlink", dir);
+  add_temp_file (symlink_name);
+
+  /* The limit 10000 is arbitrary and simply there to prevent an
+     attempt to exhaust all available disk space.  */
+  for (int size = 1; size < 10000; ++size)
+    {
+      char *contents = xmalloc (size + 1);
+      for (int i = 0; i < size; ++i)
+        contents[i] = 'a' + (rand () % 26);
+      contents[size] = '\0';
+      if (symlink (contents, symlink_name) != 0)
+        {
+          if (errno == ENAMETOOLONG)
+            {
+              printf ("info: ENAMETOOLONG failure at %d bytes\n", size);
+              free (contents);
+              break;
+            }
+          FAIL_EXIT1 ("symlink (%d bytes): %m", size);
+        }
+
+      char *readlink_result = xreadlink (symlink_name);
+      TEST_VERIFY (strcmp (readlink_result, contents) == 0);
+      free (readlink_result);
+      xunlink (symlink_name);
+      free (contents);
+    }
+
+  /* Create an empty file to suppress the temporary file deletion
+     warning.  */
+  xclose (xopen (symlink_name, O_WRONLY | O_CREAT, 0));
+
+  free (symlink_name);
+  free (dir);
+
+  return 0;
+}
+
+#include <support/test-driver.c>