Dogcows Code - chaz/tar/blob - lib/xgetcwd.c

   1 /* xgetcwd.c -- return current directory with unlimited length
   2    Copyright (C) 1992, 1996, 2000, 2001 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2, or (at your option)
   7    any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software Foundation,
  16    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  17
  18 /* Written by David MacKenzie <djm@gnu.ai.mit.edu>.  */
  19
  20 #if HAVE_CONFIG_H
  21 # include <config.h>
  22 #endif
  23
  24 #include <stdio.h>
  25 #include <errno.h>
  26 #ifndef errno
  27 extern int errno;
  28 #endif
  29
  30 #include <sys/types.h>
  31
  32 #if HAVE_STDLIB_H
  33 # include <stdlib.h>
  34 #endif
  35 #if HAVE_UNISTD_H
  36 # include <unistd.h>
  37 #endif
  38
  39 #if HAVE_GETCWD
  40 char *getcwd ();
  41 #else
  42 char *getwd ();
  43 # define getcwd(Buf, Max) getwd (Buf)
  44 #endif
  45
  46 #include "xalloc.h"
  47
  48 /* Return the current directory, newly allocated, arbitrarily long.
  49    Return NULL and set errno on error. */
  50
  51 char *
  52 xgetcwd ()
  53 {
  54 #if defined __GLIBC__ && __GLIBC__ >= 2
  55   return getcwd (NULL, 0);
  56 #else
  57   size_t buf_size = 128;  /* must be a power of 2 */
  58   char *buf = NULL;
  59
  60   while (1)
  61     {
  62       char *cwd;
  63       buf = (char *) xrealloc (buf, buf_size);
  64
  65       cwd = getcwd (buf, buf_size);
  66       if (cwd != NULL)
  67         return cwd;
  68       if (errno != ERANGE)
  69         {
  70           free (buf);
  71           return NULL;
  72         }
  73
  74       buf_size *= 2;
  75       if (buf_size == 0)
  76         xalloc_die ();
  77     }
  78 #endif
  79 }