libc/unistd/getcwd.c

   1 /*
   2  *  ZeX/OS
   3  *  Copyright (C) 2009  Tomas 'ZeXx86' Jedrzejek (zexx86@zexos.org)
   4  *
   5  *  This program is free software: you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation, either version 3 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19
  20 #include <errno.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24
  25 char *getcwd (char *buf, size_t size)
  26 {
  27         char *cwd = getenv ("PWD");
  28
  29         if (!cwd) {
  30                 errno = ENOENT;
  31                 return 0;
  32         }
  33
  34         unsigned l = strlen (cwd);
  35
  36         if (!buf) {
  37                 if (!size)
  38                         size = l;
  39                 else {
  40                         errno = EINVAL;
  41                         return 0;
  42                 }
  43
  44                 buf = (char *) malloc (sizeof (char) * size);
  45
  46                 if (!buf) {
  47                         errno = EFAULT;
  48                         return 0;
  49                 }
  50
  51         }
  52
  53         if (l > size) {
  54                 errno = ERANGE;
  55                 return 0;
  56         }
  57
  58         memcpy (buf, cwd, l);
  59         buf[l] = '\0';
  60
  61         return buf;
  62 }