lib/same.c

   1 /* Determine whether two file names refer to the same file.
   2    Copyright (C) 1997-2000 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  17
  18 /* written by Jim Meyering */
  19
  20 #if HAVE_CONFIG_H
  21 # include <config.h>
  22 #endif
  23
  24 #include <stdio.h>
  25 #ifdef HAVE_UNISTD_H
  26 # include <unistd.h>
  27 #endif
  28 #if HAVE_STDLIB_H
  29 # include <stdlib.h>
  30 #endif
  31 #include <sys/types.h>
  32 #include <sys/stat.h>
  33 #include <ctype.h>
  34 #include <errno.h>
  35 #ifndef errno
  36 extern int errno;
  37 #endif
  38
  39 #include "same.h"
  40 #include "dirname.h"
  41 #include "error.h"
  42
  43 #if ENABLE_NLS
  44 # include <libintl.h>
  45 # define _(Text) gettext (Text)
  46 #else
  47 # define _(Text) Text
  48 #endif
  49
  50 #define STREQ(a, b) (strcmp ((a), (b)) == 0)
  51
  52 #ifndef HAVE_DECL_FREE
  53 void free ();
  54 #endif
  55
  56 char *base_name PARAMS ((char const *));
  57
  58 #define SAME_INODE(Stat_buf_1, Stat_buf_2) \
  59   ((Stat_buf_1).st_ino == (Stat_buf_2).st_ino \
  60    && (Stat_buf_1).st_dev == (Stat_buf_2).st_dev)
  61
  62 /* Return nonzero if SOURCE and DEST point to the same name in the same
  63    directory.  */
  64
  65 int
  66 same_name (const char *source, const char *dest)
  67 {
  68   struct stat source_dir_stats;
  69   struct stat dest_dir_stats;
  70   char *source_dirname, *dest_dirname;
  71
  72   source_dirname = dir_name (source);
  73   dest_dirname = dir_name (dest);
  74   if (source_dirname == NULL || dest_dirname == NULL)
  75     error (1, 0, _("virtual memory exhausted"));
  76
  77   if (stat (source_dirname, &source_dir_stats))
  78     {
  79       /* Shouldn't happen.  */
  80       error (1, errno, "%s", source_dirname);
  81     }
  82
  83   if (stat (dest_dirname, &dest_dir_stats))
  84     {
  85       /* Shouldn't happen.  */
  86       error (1, errno, "%s", dest_dirname);
  87     }
  88
  89   free (source_dirname);
  90   free (dest_dirname);
  91
  92   return (SAME_INODE (source_dir_stats, dest_dir_stats)
  93           && STREQ (base_name (source), base_name (dest)));
  94 }