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-rw-r--r--lib/fopen-safer.c72
1 files changed, 72 insertions, 0 deletions
diff --git a/lib/fopen-safer.c b/lib/fopen-safer.c
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+/* Invoke fopen, but avoid some glitches.
+ Copyright (C) 2001, 2004 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+
+/* Written by Paul Eggert. */
+
+#if HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#if HAVE_UNISTD_H
+# include <unistd.h>
+#endif
+#include <unistd-safer.h>
+
+#ifndef STDERR_FILENO
+# define STDERR_FILENO 2
+#endif
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdio-safer.h>
+
+/* 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;
+}