io/getdirname.c

   1 /* Copyright (C) 1992-2018 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 Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the 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    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <unistd.h>
  19 #include <include/sys/stat.h>
  20 #include <stdlib.h>
  21 #include <string.h>
  22
  23 /* Return a malloc'd string containing the current directory name.
  24    If the environment variable `PWD' is set, and its value is correct,
  25    that value is used.  */
  26
  27 char *
  28 get_current_dir_name (void)
  29 {
  30   char *pwd;
  31   struct stat64 dotstat, pwdstat;
  32
  33   pwd = getenv ("PWD");
  34   if (pwd != NULL
  35       && stat64 (".", &dotstat) == 0
  36       && stat64 (pwd, &pwdstat) == 0
  37       && pwdstat.st_dev == dotstat.st_dev
  38       && pwdstat.st_ino == dotstat.st_ino)
  39     /* The PWD value is correct.  Use it.  */
  40     return __strdup (pwd);
  41
  42   return __getcwd ((char *) NULL, 0);
  43 }