1 /* Determine whether two file names refer to the same file.
3 Copyright (C) 1997-2000, 2002-2006, 2009-2010 Free Software Foundation, Inc.
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.
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.
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/>. */
18 /* written by Jim Meyering */
26 #include <sys/types.h>
34 #ifndef _POSIX_NAME_MAX
35 # define _POSIX_NAME_MAX 14
41 #include "same-inode.h"
45 # define MIN(a, b) ((a) < (b) ? (a) : (b))
48 /* Return nonzero if SOURCE and DEST point to the same name in the same
52 same_name (const char *source, const char *dest)
54 /* Compare the basenames. */
55 char const *source_basename = last_component (source);
56 char const *dest_basename = last_component (dest);
57 size_t source_baselen = base_len (source_basename);
58 size_t dest_baselen = base_len (dest_basename);
59 bool identical_basenames =
60 (source_baselen == dest_baselen
61 && memcmp (source_basename, dest_basename, dest_baselen) == 0);
62 bool compare_dirs = identical_basenames;
65 #if ! _POSIX_NO_TRUNC && HAVE_PATHCONF && defined _PC_NAME_MAX
66 /* This implementation silently truncates components of file names. If
67 the base names might be truncated, check whether the truncated
68 base names are the same, while checking the directories. */
69 size_t slen_max = HAVE_LONG_FILE_NAMES ? 255 : _POSIX_NAME_MAX;
70 size_t min_baselen = MIN (source_baselen, dest_baselen);
71 if (slen_max <= min_baselen
72 && memcmp (source_basename, dest_basename, slen_max) == 0)
78 struct stat source_dir_stats;
79 struct stat dest_dir_stats;
80 char *source_dirname, *dest_dirname;
82 /* Compare the parent directories (via the device and inode numbers). */
83 source_dirname = dir_name (source);
84 dest_dirname = dir_name (dest);
86 if (stat (source_dirname, &source_dir_stats))
88 /* Shouldn't happen. */
89 error (1, errno, "%s", source_dirname);
92 if (stat (dest_dirname, &dest_dir_stats))
94 /* Shouldn't happen. */
95 error (1, errno, "%s", dest_dirname);
98 same = SAME_INODE (source_dir_stats, dest_dir_stats);
100 #if ! _POSIX_NO_TRUNC && HAVE_PATHCONF && defined _PC_NAME_MAX
101 if (same && ! identical_basenames)
103 long name_max = (errno = 0, pathconf (dest_dirname, _PC_NAME_MAX));
108 /* Shouldn't happen. */
109 error (1, errno, "%s", dest_dirname);
114 same = (name_max <= min_baselen
115 && memcmp (source_basename, dest_basename, name_max) == 0);
119 free (source_dirname);