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/* xgetcwd.c -- return current directory with unlimited length
Copyright (C) 1992, 1996, 2000, 2001, 2003, 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 David MacKenzie <djm@gnu.ai.mit.edu>. */
#if HAVE_CONFIG_H
# include <config.h>
#endif
#include <limits.h>
#include <stdio.h>
#include <errno.h>
#include <sys/types.h>
#include <stdlib.h>
#if HAVE_UNISTD_H
# include <unistd.h>
#endif
#if HAVE_GETCWD
char *getcwd ();
#else
# include "pathmax.h"
# define INITIAL_BUFFER_SIZE (PATH_MAX + 1)
char *getwd ();
# define getcwd(Buf, Max) getwd (Buf)
#endif
#include "xalloc.h"
#include "xgetcwd.h"
/* Return the current directory, newly allocated, assuming it fits
within PATH_MAX bytes -- this is a common system-imposed limit
on how getcwd works.
Upon an out-of-memory error, call xalloc_die.
Upon any other type of error, return NULL. */
char *
xgetcwd (void)
{
#if HAVE_GETCWD_NULL
char *cwd = getcwd (NULL, 0);
if (! cwd && errno == ENOMEM)
xalloc_die ();
return cwd;
#else
int saved_errno;
/* The initial buffer size for the working directory. A power of 2
detects arithmetic overflow earlier, but is not required. */
# ifndef INITIAL_BUFFER_SIZE
# define INITIAL_BUFFER_SIZE 128
# endif
size_t buf_size = INITIAL_BUFFER_SIZE;
while (1)
{
char *buf = xmalloc (buf_size);
char *cwd = getcwd (buf, buf_size);
if (cwd)
return cwd;
saved_errno = errno;
free (buf);
if (saved_errno != ERANGE)
break;
#ifdef PATH_MAX
if (PATH_MAX / 2 < buf_size)
{
if (PATH_MAX <= buf_size)
break;
buf_size = PATH_MAX;
continue;
}
#endif
buf_size *= 2;
if (buf_size == 0)
xalloc_die ();
}
errno = saved_errno;
return NULL;
#endif
}
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