/* xgetcwd.c -- return current directory with unlimited length   Copyright (C) 1992, 1996, 2000, 2001 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 <stdio.h>#include <errno.h>#ifndef errnoextern int errno;#endif#include <sys/types.h>#if HAVE_STDLIB_H# include <stdlib.h>#endif#if HAVE_UNISTD_H# include <unistd.h>#endif#if HAVE_GETCWDchar *getcwd ();#else# include "pathmax.h"# define INITIAL_BUFFER_SIZE (PATH_MAX + 1)char *getwd ();# define getcwd(Buf, Max) getwd (Buf)#endif#include "xalloc.h"/* Return the current directory, newly allocated, arbitrarily long.   Return NULL and set errno on error. */char *xgetcwd (){#if HAVE_GETCWD_NULL  char *cwd = getcwd (NULL, 0);  if (! cwd && errno == ENOMEM)    xalloc_die ();  return cwd;#else  /* 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);      int saved_errno;      if (cwd)	return cwd;      saved_errno = errno;      free (buf);      if (saved_errno != ERANGE)	return NULL;      buf_size *= 2;      if (buf_size == 0)	xalloc_die ();    }#endif}