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 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ 17 18 /* Written by David MacKenzie <djm@gnu.ai.mit.edu>. */ 19 20 #include <config.h> 21 22 #include <stdlib.h> 23 #include <stdio.h> 24 #include <errno.h> 25 #include <sys/types.h> 26 #include <unistd.h> 27 28 #include "pathmax.h" 29 30 #if HAVE_GETCWD 31 # ifdef VMS 32 /* We want the directory in Unix syntax, not in VMS syntax. */ 33 # define getcwd(Buf, Max) (getcwd) (Buf, Max, 0) 34 # else 35 char *getcwd (); 36 # endif 37 #else 38 char *getwd (); 39 # define getcwd(Buf, Max) getwd (Buf) 40 #endif 41 42 #include "xalloc.h" 43 44 /* Return the current directory, newly allocated, arbitrarily long. 45 Return NULL and set errno on error. */ 46 47 char * 48 xgetcwd () 49 { 50 char *ret; 51 unsigned path_max; 52 char buf[1024]; 53 54 errno = 0; 55 ret = getcwd (buf, sizeof (buf)); 56 if (ret != NULL) 57 return xstrdup (buf); 58 if (errno != ERANGE) 59 return NULL; 60 61 path_max = (unsigned) PATH_MAX; 62 path_max += 2; /* The getcwd docs say to do this. */ 63 64 for (;;) 65 { 66 char *cwd = (char *) xmalloc (path_max); 67 68 errno = 0; 69 ret = getcwd (cwd, path_max); 70 if (ret != NULL) 71 return ret; 72 if (errno != ERANGE) 73 { 74 int save_errno = errno; 75 free (cwd); 76 errno = save_errno; 77 return NULL; 78 } 79 80 free (cwd); 81 82 path_max += path_max / 16; 83 path_max += 32; 84 } 85 } 86