1 files changed, 97 insertions, 0 deletions
diff --git a/gnulib-tests/test-freopen-safer.c b/gnulib-tests/test-freopen-safer.c
new file mode 100644
index 0000000..958fc89
--- /dev/null
+++ b/gnulib-tests/test-freopen-safer.c
@@ -0,0 +1,97 @@
+/* Test of reopening a stream.
+   Copyright (C) 2009-2023 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>
+
+/* Specification.  */
+#include "stdio--.h"
+
+/* Helpers.  */
+#include <unistd.h>
+
+/* This test intentionally closes stderr.  So, we arrange to have fd 10
+   (outside the range of interesting fd's during the test) set up to
+   duplicate the original stderr.  */
+
+#define BACKUP_STDERR_FILENO 10
+#define ASSERT_STREAM myerr
+#include "macros.h"
+
+static FILE *myerr;
+
+int
+main (void)
+{
+  FILE *fp;
+
+  /* We close fd 2 later, so save it in fd 10.  */
+  if (dup2 (STDERR_FILENO, BACKUP_STDERR_FILENO) != BACKUP_STDERR_FILENO
+      || (myerr = fdopen (BACKUP_STDERR_FILENO, "w")) == NULL)
+    return 2;
+
+  {
+    FILE *tmp;
+    ASSERT (tmp = fopen ("/dev/null", "r"));
+    ASSERT (STDERR_FILENO < fileno (tmp));
+    ASSERT (fp = fopen ("/dev/null", "w"));
+    ASSERT (fileno (tmp) < fileno (fp));
+    ASSERT (fclose (tmp) == 0);
+  }
+
+  /* Gap in fds.  */
+  ASSERT (freopen ("/dev/null", "r+", fp) == fp);
+  ASSERT (STDERR_FILENO < fileno (fp));
+
+  ASSERT (freopen ("/dev/null", "r", stdin) == stdin);
+  ASSERT (STDIN_FILENO == fileno (stdin));
+
+  ASSERT (freopen ("/dev/null", "w", stdout) == stdout);
+  ASSERT (STDOUT_FILENO == fileno (stdout));
+
+  ASSERT (freopen ("/dev/null", "w", stderr) == stderr);
+  ASSERT (STDERR_FILENO == fileno (stderr));
+
+  /* fd 0 closed.  */
+  ASSERT (close (STDIN_FILENO) == 0);
+
+  ASSERT (freopen ("/dev/null", "w", stdout) == stdout);
+  ASSERT (STDOUT_FILENO == fileno (stdout));
+
+  ASSERT (freopen ("/dev/null", "w", stderr) == stderr);
+  ASSERT (STDERR_FILENO == fileno (stderr));
+
+  ASSERT (freopen ("/dev/null", "a", fp) == fp);
+  ASSERT (STDERR_FILENO < fileno (fp));
+
+  /* fd 1 closed.  */
+  ASSERT (close (STDOUT_FILENO) == 0);
+
+  ASSERT (freopen ("/dev/null", "w", stderr) == stderr);
+  ASSERT (STDERR_FILENO == fileno (stderr));
+
+  ASSERT (freopen ("/dev/null", "a+", fp) == fp);
+  ASSERT (STDERR_FILENO < fileno (fp));
+
+  /* fd 2 closed.  */
+  ASSERT (close (STDERR_FILENO) == 0);
+
+  ASSERT (freopen ("/dev/null", "w+", fp) == fp);
+  ASSERT (STDERR_FILENO < fileno (fp));
+
+  return 0;
+}