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/* Provide a replacement for the POSIX getcwd function.
Copyright (C) 2003 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 Jim Meyering */
#include <config.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#ifndef errno
extern int errno;
#endif
#include <sys/types.h>
#include "pathmax.h"
#include "same.h"
/* Guess high, because that makes the test below more conservative.
But this is a kludge, because we should really use
pathconf (".", _PC_NAME_MAX). But it's probably not worth the cost. */
#define KLUDGE_POSIX_NAME_MAX 255
#define MAX_SAFE_LEN (PATH_MAX - 1 - KLUDGE_POSIX_NAME_MAX - 1)
/* Undefine getcwd here, as near the use as possible, in case any
of the files included above define it to rpl_getcwd. */
#undef getcwd
/* Any declaration of getcwd from headers included above has
been changed to a declaration of rpl_getcwd. Declare it here. */
extern char *getcwd (char *buf, size_t size);
/* This is a wrapper for getcwd.
Some implementations (at least GNU libc 2.3.1 + linux-2.4.20) return
non-NULL for a working directory name longer than PATH_MAX, yet the
returned string is a strict prefix of the desired directory name.
Upon such a failure, free the offending string, set errno to
ENAMETOOLONG, and return NULL.
I've heard that this is a Linux kernel bug, and that it has
been fixed between 2.4.21-pre3 and 2.4.21-pre4. */
char *
rpl_getcwd (char *buf, size_t size)
{
char *cwd = getcwd (buf, size);
if (cwd == NULL)
return NULL;
if (strlen (cwd) <= MAX_SAFE_LEN || same_name (cwd, "."))
return cwd;
free (cwd);
errno = ENAMETOOLONG;
return NULL;
}
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