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/* Determine whether two file names refer to the same file.
Copyright (C) 1997, 1998, 1999, 2000, 2002, 2003, 2004 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
/* written by Jim Meyering */
#if HAVE_CONFIG_H
# include <config.h>
#endif
#include <stdbool.h>
#include <stdio.h>
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <ctype.h>
#include <errno.h>
#include <string.h>
#include <limits.h>
#ifndef _POSIX_NAME_MAX
# define _POSIX_NAME_MAX 14
#endif
#include "same.h"
#include "dirname.h"
#include "error.h"
#include "xalloc.h"
#define MIN(a, b) ((a) < (b) ? (a) : (b))
#define SAME_INODE(Stat_buf_1, Stat_buf_2) \
((Stat_buf_1).st_ino == (Stat_buf_2).st_ino \
&& (Stat_buf_1).st_dev == (Stat_buf_2).st_dev)
/* 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 = base_name (source);
char const *dest_basename = base_name (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 pathname components. 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;
}
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