diff options
Diffstat (limited to 'lib/fopen-safer.c')
-rw-r--r-- | lib/fopen-safer.c | 69 |
1 files changed, 69 insertions, 0 deletions
diff --git a/lib/fopen-safer.c b/lib/fopen-safer.c new file mode 100644 index 00000000..4f2ffa1b --- /dev/null +++ b/lib/fopen-safer.c @@ -0,0 +1,69 @@ +/* Invoke fopen, but avoid some glitches. + Copyright (C) 2001, 2004, 2005 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. */ + +#ifdef HAVE_CONFIG_H +# include <config.h> +#endif + +#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; +} |