io/getdirname.c

   1 /* Copyright (C) 1992 Free Software Foundation, Inc.
   2 This file is part of the GNU C Library.
   3
   4 The GNU C Library is free software; you can redistribute it and/or
   5 modify it under the terms of the GNU Library General Public License as
   6 published by the Free Software Foundation; either version 2 of the
   7 License, or (at your option) any later version.
   8
   9 The GNU C Library 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 GNU
  12 Library General Public License for more details.
  13
  14 You should have received a copy of the GNU Library General Public
  15 License along with the GNU C Library; see the file COPYING.LIB.  If
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 #include <ansidecl.h>
  20 #include <unistd.h>
  21 #include <sys/stat.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24
  25 /* Return a malloc'd string containing the current directory name.
  26    If the environment variable `PWD' is set, and its value is correct,
  27    that value is used.  */
  28
  29 char *
  30 DEFUN_VOID(get_current_dir_name)
  31 {
  32   char *pwd;
  33   struct stat dotstat, pwdstat;
  34
  35   pwd = getenv ("PWD");
  36   if (pwd != NULL &&
  37       stat (".", &dotstat) == 0 &&
  38       stat (pwd, &pwdstat) == 0 &&
  39       pwdstat.st_dev == dotstat.st_dev &&
  40       pwdstat.st_ino == dotstat.st_ino)
  41     /* The PWD value is correct.  Use it.  */
  42     return strdup (pwd);
  43
  44   return getcwd ((char *) NULL, 0);
  45 }