coreutils-6.9coreutils-6.9

1 files changed, 68 insertions, 0 deletions

diff --git a/lib/fopen-safer.c b/lib/fopen-safer.c
new file mode 100644
index 0000000..3502dba
--- /dev/null
+++ b/lib/fopen-safer.c
@@ -0,0 +1,68 @@
+/* Invoke fopen, but avoid some glitches.
+
+   Copyright (C) 2001, 2004, 2005, 2006 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 2, 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, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+/* Written by Paul Eggert.  */
+
+#include <config.h>
+
+#include "stdio-safer.h"
+
+#include <errno.h>
+#include <unistd.h>
+#include "unistd-safer.h"
+
+#ifndef STDERR_FILENO
+# define STDERR_FILENO 2
+#endif
+
+/* Like fopen, but do not return stdin, stdout, or stderr.  */
+
+FILE *
+fopen_safer (char const *file, char const *mode)
+{
+  FILE *fp = fopen (file, mode);
+
+  if (fp)
+    {
+      int fd = fileno (fp);
+
+      if (0 <= fd && fd <= STDERR_FILENO)
+	{
+	  int f = dup_safer (fd);
+
+	  if (f < 0)
+	    {
+	      int e = errno;
+	      fclose (fp);
+	      errno = e;
+	      return NULL;
+	    }
+
+	  if (fclose (fp) != 0
+	      || ! (fp = fdopen (f, mode)))
+	    {
+	      int e = errno;
+	      close (f);
+	      errno = e;
+	      return NULL;
+	    }
+	}
+    }
+
+  return fp;
+}