1/* xgetcwd.c -- return current directory with unlimited length 2 Copyright (C) 1992, 1996, 2000, 2003, 2005-2006 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 3 of the License, or 7 (at your option) 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, see <http://www.gnu.org/licenses/>. */ 16 17/* Written by David MacKenzie <djm@gnu.ai.mit.edu>. */ 18 19#include <config.h> 20 21#include <stdlib.h> 22#include <stdio.h> 23#include <errno.h> 24#include <sys/types.h> 25#include <unistd.h> 26 27#include "pathmax.h" 28 29#if HAVE_GETCWD 30# ifdef VMS 31 /* We want the directory in Unix syntax, not in VMS syntax. */ 32# define getcwd(Buf, Max) (getcwd) (Buf, Max, 0) 33# else 34char *getcwd (); 35# endif 36#else 37char *getwd (); 38# define getcwd(Buf, Max) getwd (Buf) 39#endif 40 41#include "xalloc.h" 42 43/* Return the current directory, newly allocated, arbitrarily long. 44 Return NULL and set errno on error. */ 45 46char * 47xgetcwd () 48{ 49 char *ret; 50 unsigned path_max; 51 char buf[1024]; 52 53 errno = 0; 54 ret = getcwd (buf, sizeof (buf)); 55 if (ret != NULL) 56 return xstrdup (buf); 57 if (errno != ERANGE) 58 return NULL; 59 60 path_max = (unsigned) PATH_MAX; 61 path_max += 2; /* The getcwd docs say to do this. */ 62 63 for (;;) 64 { 65 char *cwd = XNMALLOC (path_max, char); 66 67 errno = 0; 68 ret = getcwd (cwd, path_max); 69 if (ret != NULL) 70 return ret; 71 if (errno != ERANGE) 72 { 73 int save_errno = errno; 74 free (cwd); 75 errno = save_errno; 76 return NULL; 77 } 78 79 free (cwd); 80 81 path_max += path_max / 16; 82 path_max += 32; 83 } 84} 85