1 files changed, 87 insertions, 0 deletions
diff --git a/tests/test-fdopendir.c b/tests/test-fdopendir.c
new file mode 100644
index 00000000..3430d03b
--- /dev/null
+++ b/tests/test-fdopendir.c
@@ -0,0 +1,87 @@
+/* Test opening a directory stream from a file descriptor.
+   Copyright (C) 2009-2024 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 <dirent.h>
+
+#include "signature.h"
+SIGNATURE_CHECK (fdopendir, DIR *, (int));
+
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "macros.h"
+
+int
+main ()
+{
+  DIR *d;
+  int fd;
+
+  /* A non-directory cannot be turned into a directory stream.  */
+  fd = open ("test-fdopendir.tmp", O_RDONLY | O_CREAT, 0600);
+  ASSERT (0 <= fd);
+  errno = 0;
+  ASSERT (fdopendir (fd) == NULL);
+  ASSERT (errno == ENOTDIR);
+  ASSERT (close (fd) == 0);
+  ASSERT (unlink ("test-fdopendir.tmp") == 0);
+
+  /* A bad fd cannot be turned into a stream.  */
+  {
+    errno = 0;
+    ASSERT (fdopendir (-1) == NULL);
+    ASSERT (errno == EBADF);
+  }
+  {
+    close (99);
+    errno = 0;
+    ASSERT (fdopendir (99) == NULL);
+    ASSERT (errno == EBADF);
+  }
+#ifdef AT_FDCWD
+  {
+    errno = 0;
+    ASSERT (fdopendir (AT_FDCWD) == NULL);
+    ASSERT (errno == EBADF);
+  }
+#endif
+
+  /* This should work.  */
+  fd = open (".", O_RDONLY);
+  ASSERT (0 <= fd);
+  d = fdopendir (fd);
+  ASSERT (d);
+  /* fdopendir should not close fd.  */
+  ASSERT (dup2 (fd, fd) == fd);
+
+  /* Don't test dirfd here.  dirfd (d) must return fd on current POSIX
+     platforms, but on pre-2008 platforms or on non-POSIX platforms
+     dirfd (fd) might return some other descriptor, or -1, and gnulib
+     does not work around this porting problem.  */
+
+  ASSERT (closedir (d) == 0);
+  /* Now we can guarantee that fd must be closed.  */
+  errno = 0;
+  ASSERT (dup2 (fd, fd) == -1);
+  ASSERT (errno == EBADF);
+
+  return test_exit_status;
+}