1 files changed, 121 insertions, 0 deletions
diff --git a/gnulib-tests/test-readlinkat.c b/gnulib-tests/test-readlinkat.c
new file mode 100644
index 0000000..64e8f22
--- /dev/null
+++ b/gnulib-tests/test-readlinkat.c
@@ -0,0 +1,121 @@
+/* Tests of readlinkat.
+   Copyright (C) 2009-2022 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Eric Blake <ebb9@byu.net>, 2009.  */
+
+#include <config.h>
+
+#include <unistd.h>
+
+#include "signature.h"
+SIGNATURE_CHECK (readlinkat, ssize_t, (int, char const *, char *, size_t));
+
+#include <fcntl.h>
+#include <errno.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+
+#include "ignore-value.h"
+#include "macros.h"
+
+#ifndef HAVE_SYMLINK
+# define HAVE_SYMLINK 0
+#endif
+
+#define BASE "test-readlinkat.t"
+
+#include "test-readlink.h"
+
+static int dfd = AT_FDCWD;
+
+static ssize_t
+do_readlink (char const *name, char *buf, size_t len)
+{
+  return readlinkat (dfd, name, buf, len);
+}
+
+int
+main (void)
+{
+  char buf[80];
+  int result;
+
+  /* Remove any leftovers from a previous partial run.  */
+  ignore_value (system ("rm -rf " BASE "*"));
+
+  /* Test behaviour for invalid file descriptors.  */
+  {
+    errno = 0;
+    ASSERT (readlinkat (-1, "foo", buf, sizeof buf) == -1);
+    ASSERT (errno == EBADF);
+  }
+  {
+    close (99);
+    errno = 0;
+    ASSERT (readlinkat (99, "foo", buf, sizeof buf) == -1);
+    ASSERT (errno == EBADF);
+  }
+
+  /* Perform same checks as counterpart functions.  */
+  result = test_readlink (do_readlink, false);
+  dfd = openat (AT_FDCWD, ".", O_RDONLY);
+  ASSERT (0 <= dfd);
+  ASSERT (test_readlink (do_readlink, false) == result);
+
+  /* Now perform some cross-directory checks.  Skip everything else on
+     mingw.  */
+  if (HAVE_SYMLINK)
+    {
+      const char *contents = "don't matter!";
+      ssize_t exp = strlen (contents);
+
+      /* Create link while cwd is '.', then read it in '..'.  */
+      ASSERT (symlinkat (contents, AT_FDCWD, BASE "link") == 0);
+      errno = 0;
+      ASSERT (symlinkat (contents, dfd, BASE "link") == -1);
+      ASSERT (errno == EEXIST);
+      ASSERT (chdir ("..") == 0);
+      errno = 0;
+      ASSERT (readlinkat (AT_FDCWD, BASE "link", buf, sizeof buf) == -1);
+      ASSERT (errno == ENOENT);
+      ASSERT (readlinkat (dfd, BASE "link", buf, sizeof buf) == exp);
+      ASSERT (strncmp (contents, buf, exp) == 0);
+      ASSERT (unlinkat (dfd, BASE "link", 0) == 0);
+
+      /* Create link while cwd is '..', then read it in '.'.  */
+      ASSERT (symlinkat (contents, dfd, BASE "link") == 0);
+      ASSERT (fchdir (dfd) == 0);
+      errno = 0;
+      ASSERT (symlinkat (contents, AT_FDCWD, BASE "link") == -1);
+      ASSERT (errno == EEXIST);
+      buf[0] = '\0';
+      ASSERT (readlinkat (AT_FDCWD, BASE "link", buf, sizeof buf) == exp);
+      ASSERT (strncmp (contents, buf, exp) == 0);
+      buf[0] = '\0';
+      ASSERT (readlinkat (dfd, BASE "link", buf, sizeof buf) == exp);
+      ASSERT (strncmp (contents, buf, exp) == 0);
+      ASSERT (unlink (BASE "link") == 0);
+    }
+
+  ASSERT (close (dfd) == 0);
+  if (result == 77)
+    fputs ("skipping test: symlinks not supported on this file system\n",
+           stderr);
+  return result;
+}