/* Determine whether two file names refer to the same file. Copyright (C) 1997, 1998, 1999, 2000, 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ /* written by Jim Meyering */ #include #include #include #include #include #include #include #include #include #include #include #ifndef _POSIX_NAME_MAX # define _POSIX_NAME_MAX 14 #endif #include "same.h" #include "dirname.h" #include "error.h" #include "same-inode.h" #include "xalloc.h" #ifndef MIN # define MIN(a, b) ((a) < (b) ? (a) : (b)) #endif /* Return nonzero if SOURCE and DEST point to the same name in the same directory. */ bool same_name (const char *source, const char *dest) { /* Compare the basenames. */ char const *source_basename = last_component (source); char const *dest_basename = last_component (dest); size_t source_baselen = base_len (source_basename); size_t dest_baselen = base_len (dest_basename); bool identical_basenames = (source_baselen == dest_baselen && memcmp (source_basename, dest_basename, dest_baselen) == 0); bool compare_dirs = identical_basenames; bool same = false; #if ! _POSIX_NO_TRUNC && HAVE_PATHCONF && defined _PC_NAME_MAX /* This implementation silently truncates components of file names. If the base names might be truncated, check whether the truncated base names are the same, while checking the directories. */ size_t slen_max = HAVE_LONG_FILE_NAMES ? 255 : _POSIX_NAME_MAX; size_t min_baselen = MIN (source_baselen, dest_baselen); if (slen_max <= min_baselen && memcmp (source_basename, dest_basename, slen_max) == 0) compare_dirs = true; #endif if (compare_dirs) { struct stat source_dir_stats; struct stat dest_dir_stats; char *source_dirname, *dest_dirname; /* Compare the parent directories (via the device and inode numbers). */ source_dirname = dir_name (source); dest_dirname = dir_name (dest); if (stat (source_dirname, &source_dir_stats)) { /* Shouldn't happen. */ error (1, errno, "%s", source_dirname); } if (stat (dest_dirname, &dest_dir_stats)) { /* Shouldn't happen. */ error (1, errno, "%s", dest_dirname); } same = SAME_INODE (source_dir_stats, dest_dir_stats); #if ! _POSIX_NO_TRUNC && HAVE_PATHCONF && defined _PC_NAME_MAX if (same && ! identical_basenames) { long name_max = (errno = 0, pathconf (dest_dirname, _PC_NAME_MAX)); if (name_max < 0) { if (errno) { /* Shouldn't happen. */ error (1, errno, "%s", dest_dirname); } same = false; } else same = (name_max <= min_baselen && memcmp (source_basename, dest_basename, name_max) == 0); } #endif free (source_dirname); free (dest_dirname); } return same; }