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 #if HAVE_STRING_H
  40 # include <string.h>
  41 #else
  42 # include <strings.h>
  43 #endif
  44
  45 #include "same.h"
  46 #include "dirname.h"
  47 #include "error.h"
  48 #include "xalloc.h"
  49
  50 #if ENABLE_NLS
  51 # include <libintl.h>
  52 # define _(Text) gettext (Text)
  53 #else
  54 # define _(Text) Text
  55 #endif
  56
  57 #ifndef HAVE_DECL_FREE
  58 "this configure-time declaration test was not run"
  59 #endif
  60 #if !HAVE_DECL_FREE
  61 void free ();
  62 #endif
  63
  64 #define SAME_INODE(Stat_buf_1, Stat_buf_2) \
  65   ((Stat_buf_1).st_ino == (Stat_buf_2).st_ino \
  66    && (Stat_buf_1).st_dev == (Stat_buf_2).st_dev)
  67
  68 /* Return nonzero if SOURCE and DEST point to the same name in the same
  69    directory.  */
  70
  71 int
  72 same_name (const char *source, const char *dest)
  73 {
  74   struct stat source_dir_stats;
  75   struct stat dest_dir_stats;
  76   char *source_dirname, *dest_dirname;
  77   char *source_basename, *dest_basename;
  78   size_t source_baselen, dest_baselen;
  79
  80   source_dirname = dir_name (source);
  81   dest_dirname = dir_name (dest);
  82
  83   if (stat (source_dirname, &source_dir_stats))
  84     {
  85       /* Shouldn't happen.  */
  86       error (1, errno, "%s", source_dirname);
  87     }
  88
  89   if (stat (dest_dirname, &dest_dir_stats))
  90     {
  91       /* Shouldn't happen.  */
  92       error (1, errno, "%s", dest_dirname);
  93     }
  94
  95   free (source_dirname);
  96   free (dest_dirname);
  97
  98   if (! SAME_INODE (source_dir_stats, dest_dir_stats))
  99     return 0;
 100
 101   source_basename = base_name (source);
 102   dest_basename = base_name (dest);
 103   source_baselen = base_len (source_basename);
 104   dest_baselen = base_len (dest_basename);
 105   return (source_baselen == dest_baselen
 106           && memcmp (source_basename, dest_basename, dest_baselen) == 0);
 107 }