1 files changed, 148 insertions, 0 deletions
diff --git a/tests/test-cloexec.c b/tests/test-cloexec.c
new file mode 100644
index 00000000..74928b4a
--- /dev/null
+++ b/tests/test-cloexec.c
@@ -0,0 +1,148 @@
+/* Test duplicating non-inheritable file descriptors.
+   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 "cloexec.h"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#if defined _WIN32 && ! defined __CYGWIN__
+/* Get declarations of the native Windows API functions.  */
+# define WIN32_LEAN_AND_MEAN
+# include <windows.h>
+/* Get _get_osfhandle.  */
+# if GNULIB_MSVC_NOTHROW
+#  include "msvc-nothrow.h"
+# else
+#  include <io.h>
+# endif
+#endif
+
+#include "binary-io.h"
+#include "macros.h"
+
+/* Return non-zero if FD is open and inheritable across exec/spawn.  */
+static int
+is_inheritable (int fd)
+{
+#if defined _WIN32 && ! defined __CYGWIN__
+  /* On native Windows, the initial state of unassigned standard file
+     descriptors is that they are open but point to an
+     INVALID_HANDLE_VALUE, and there is no fcntl.  */
+  HANDLE h = (HANDLE) _get_osfhandle (fd);
+  DWORD flags;
+  if (h == INVALID_HANDLE_VALUE || GetHandleInformation (h, &flags) == 0)
+    return 0;
+  return (flags & HANDLE_FLAG_INHERIT) != 0;
+#else
+# ifndef F_GETFD
+#  error Please port fcntl to your platform
+# endif
+  int i = fcntl (fd, F_GETFD);
+  return 0 <= i && (i & FD_CLOEXEC) == 0;
+#endif
+}
+
+#if !O_BINARY
+# define set_binary_mode(f,m) zero ()
+static int zero (void) { return 0; }
+#endif
+
+/* Return non-zero if FD is open in the given MODE, which is either
+   O_TEXT or O_BINARY.  */
+static int
+is_mode (int fd, int mode)
+{
+  int value = set_binary_mode (fd, O_BINARY);
+  set_binary_mode (fd, value);
+  return mode == value;
+}
+
+int
+main (void)
+{
+  const char *file = "test-cloexec.tmp";
+  int fd = creat (file, 0600);
+  int fd2;
+  int bad_fd = getdtablesize ();
+
+  /* Assume std descriptors were provided by invoker.  */
+  ASSERT (STDERR_FILENO < fd);
+  ASSERT (is_inheritable (fd));
+
+  /* Normal use of set_cloexec_flag.  */
+  ASSERT (set_cloexec_flag (fd, true) == 0);
+#if !(defined _WIN32 && ! defined __CYGWIN__)
+  ASSERT (!is_inheritable (fd));
+#endif
+  ASSERT (set_cloexec_flag (fd, false) == 0);
+  ASSERT (is_inheritable (fd));
+
+  /* Normal use of dup_cloexec.  */
+  fd2 = dup_cloexec (fd);
+  ASSERT (fd < fd2);
+  ASSERT (!is_inheritable (fd2));
+  ASSERT (close (fd) == 0);
+  ASSERT (dup_cloexec (fd2) == fd);
+  ASSERT (!is_inheritable (fd));
+  ASSERT (close (fd2) == 0);
+
+  /* On systems that distinguish between text and binary mode,
+     dup_cloexec reuses the mode of the source.  */
+  set_binary_mode (fd, O_BINARY);
+  ASSERT (is_mode (fd, O_BINARY));
+  fd2 = dup_cloexec (fd);
+  ASSERT (fd < fd2);
+  ASSERT (is_mode (fd2, O_BINARY));
+  ASSERT (close (fd2) == 0);
+  set_binary_mode (fd, O_TEXT);
+  ASSERT (is_mode (fd, O_TEXT));
+  fd2 = dup_cloexec (fd);
+  ASSERT (fd < fd2);
+  ASSERT (is_mode (fd2, O_TEXT));
+  ASSERT (close (fd2) == 0);
+
+  /* Test error handling.  */
+  errno = 0;
+  ASSERT (set_cloexec_flag (-1, false) == -1);
+  ASSERT (errno == EBADF);
+  errno = 0;
+  ASSERT (set_cloexec_flag (bad_fd, false) == -1);
+  ASSERT (errno == EBADF);
+  errno = 0;
+  ASSERT (set_cloexec_flag (fd2, false) == -1);
+  ASSERT (errno == EBADF);
+  errno = 0;
+  ASSERT (dup_cloexec (-1) == -1);
+  ASSERT (errno == EBADF);
+  errno = 0;
+  ASSERT (dup_cloexec (bad_fd) == -1);
+  ASSERT (errno == EBADF);
+  errno = 0;
+  ASSERT (dup_cloexec (fd2) == -1);
+  ASSERT (errno == EBADF);
+
+  /* Clean up.  */
+  ASSERT (close (fd) == 0);
+  ASSERT (unlink (file) == 0);
+
+  return 0;
+}