1 files changed, 222 insertions, 0 deletions
diff --git a/tests/test-dup2.c b/tests/test-dup2.c
new file mode 100644
index 00000000..1041525b
--- /dev/null
+++ b/tests/test-dup2.c
@@ -0,0 +1,222 @@
+/* Test duplicating 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 <unistd.h>
+
+#include "signature.h"
+SIGNATURE_CHECK (dup2, int, (int, int));
+
+#include <errno.h>
+#include <fcntl.h>
+
+#if HAVE_SYS_RESOURCE_H
+# include <sys/resource.h>
+#endif
+
+#include "binary-io.h"
+
+#if GNULIB_TEST_CLOEXEC
+# include "cloexec.h"
+#endif
+
+#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 "macros.h"
+
+/* Return non-zero if FD is open.  */
+static int
+is_open (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.  */
+  return (HANDLE) _get_osfhandle (fd) != INVALID_HANDLE_VALUE;
+#else
+# ifndef F_GETFL
+#  error Please port fcntl to your platform
+# endif
+  return 0 <= fcntl (fd, F_GETFL);
+#endif
+}
+
+#if GNULIB_TEST_CLOEXEC
+/* 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
+}
+#endif /* GNULIB_TEST_CLOEXEC */
+
+#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-dup2.tmp";
+  char buffer[1];
+  int bad_fd = getdtablesize ();
+  int fd = open (file, O_CREAT | O_TRUNC | O_RDWR, 0600);
+
+  /* Assume std descriptors were provided by invoker.  */
+  ASSERT (STDERR_FILENO < fd);
+  ASSERT (is_open (fd));
+  /* Ignore any other fd's leaked into this process.  */
+  close (fd + 1);
+  close (fd + 2);
+  ASSERT (!is_open (fd + 1));
+  ASSERT (!is_open (fd + 2));
+
+  /* Assigning to self must be a no-op.  */
+  ASSERT (dup2 (fd, fd) == fd);
+  ASSERT (is_open (fd));
+
+  /* The source must be valid.  */
+  errno = 0;
+  ASSERT (dup2 (-1, fd) == -1);
+  ASSERT (errno == EBADF);
+  close (99);
+  errno = 0;
+  ASSERT (dup2 (99, fd) == -1);
+  ASSERT (errno == EBADF);
+  errno = 0;
+  ASSERT (dup2 (AT_FDCWD, fd) == -1);
+  ASSERT (errno == EBADF);
+  ASSERT (is_open (fd));
+
+  /* If the source is not open, then the destination is unaffected.  */
+  errno = 0;
+  ASSERT (dup2 (fd + 1, fd + 1) == -1);
+  ASSERT (errno == EBADF);
+  ASSERT (!is_open (fd + 1));
+  errno = 0;
+  ASSERT (dup2 (fd + 1, fd) == -1);
+  ASSERT (errno == EBADF);
+  ASSERT (is_open (fd));
+
+  /* The destination must be valid.  */
+  errno = 0;
+  ASSERT (dup2 (fd, -2) == -1);
+  ASSERT (errno == EBADF);
+  if (bad_fd > 256)
+    {
+      ASSERT (dup2 (fd, 255) == 255);
+      ASSERT (dup2 (fd, 256) == 256);
+      ASSERT (close (255) == 0);
+      ASSERT (close (256) == 0);
+    }
+  ASSERT (dup2 (fd, bad_fd - 1) == bad_fd - 1);
+  ASSERT (close (bad_fd - 1) == 0);
+  errno = 0;
+  ASSERT (dup2 (fd, bad_fd) == -1);
+  ASSERT (errno == EBADF);
+
+  /* Using dup2 can skip fds.  */
+  ASSERT (dup2 (fd, fd + 2) == fd + 2);
+  ASSERT (is_open (fd));
+  ASSERT (!is_open (fd + 1));
+  ASSERT (is_open (fd + 2));
+
+  /* Verify that dup2 closes the previous occupant of a fd.  */
+  ASSERT (open ("/dev/null", O_WRONLY, 0600) == fd + 1);
+  ASSERT (dup2 (fd + 1, fd) == fd);
+  ASSERT (close (fd + 1) == 0);
+  ASSERT (write (fd, "1", 1) == 1);
+  ASSERT (dup2 (fd + 2, fd) == fd);
+  ASSERT (lseek (fd, 0, SEEK_END) == 0);
+  ASSERT (write (fd + 2, "2", 1) == 1);
+  ASSERT (lseek (fd, 0, SEEK_SET) == 0);
+  ASSERT (read (fd, buffer, 1) == 1);
+  ASSERT (*buffer == '2');
+
+#if GNULIB_TEST_CLOEXEC
+  /* Any new fd created by dup2 must not be cloexec.  */
+  ASSERT (close (fd + 2) == 0);
+  ASSERT (dup_cloexec (fd) == fd + 1);
+  ASSERT (!is_inheritable (fd + 1));
+  ASSERT (dup2 (fd + 1, fd + 1) == fd + 1);
+  ASSERT (!is_inheritable (fd + 1));
+  ASSERT (dup2 (fd + 1, fd + 2) == fd + 2);
+  ASSERT (!is_inheritable (fd + 1));
+  ASSERT (is_inheritable (fd + 2));
+  errno = 0;
+  ASSERT (dup2 (fd + 1, -1) == -1);
+  ASSERT (errno == EBADF);
+  ASSERT (!is_inheritable (fd + 1));
+#endif
+
+  /* On systems that distinguish between text and binary mode, dup2
+     reuses the mode of the source.  */
+  set_binary_mode (fd, O_BINARY);
+  ASSERT (is_mode (fd, O_BINARY));
+  ASSERT (dup2 (fd, fd + 1) == fd + 1);
+  ASSERT (is_mode (fd + 1, O_BINARY));
+  set_binary_mode (fd, O_TEXT);
+  ASSERT (is_mode (fd, O_TEXT));
+  ASSERT (dup2 (fd, fd + 1) == fd + 1);
+  ASSERT (is_mode (fd + 1, O_TEXT));
+
+  /* Clean up.  */
+  ASSERT (close (fd + 2) == 0);
+  ASSERT (close (fd + 1) == 0);
+  ASSERT (close (fd) == 0);
+  ASSERT (unlink (file) == 0);
+
+  return 0;
+}