1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
|
/* Determine whether two file names refer to the same file.
Copyright (C) 1997-2000, 2002-2006, 2009-2019 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 3 of the License, 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, see <https://www.gnu.org/licenses/>. */
/* written by Jim Meyering */
#include <config.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stdio.h>
#include <unistd.h>
#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 "same-inode.h"
#ifndef MIN
# define MIN(a, b) ((a) < (b) ? (a) : (b))
#endif
/* Whether file name components are silently truncated (behavior that
POSIX stopped allowing in 2008). This enables checks whether
truncated base names are the same, while checking the directories. */
#if !_POSIX_NO_TRUNC && HAVE_FPATHCONF && defined _PC_NAME_MAX
# define CHECK_TRUNCATION true
#else
# define CHECK_TRUNCATION false
#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)
{
return same_nameat (AT_FDCWD, source, AT_FDCWD, dest);
}
/* Likewise, but interpret the file names relative to SOURCE_FD and DEST_FD,
in the style of openat. */
bool
same_nameat (int source_dfd, char const *source,
int dest_dfd, char const *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 CHECK_TRUNCATION
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;
/* Compare the parent directories (via the device and inode numbers). */
char *source_dirname = dir_name (source);
int flags = AT_SYMLINK_NOFOLLOW;
if (fstatat (source_dfd, source_dirname, &source_dir_stats, flags) != 0)
{
/* Shouldn't happen. */
error (1, errno, "%s", source_dirname);
}
free (source_dirname);
char *dest_dirname = dir_name (dest);
#if CHECK_TRUNCATION
int destdir_errno = 0;
int open_flags = O_SEARCH | O_CLOEXEC | O_DIRECTORY;
int destdir_fd = openat (dest_dfd, dest_dirname, open_flags);
if (destdir_fd < 0 || fstat (destdir_fd, &dest_dir_stats) != 0)
destdir_errno = errno;
else if (SAME_INODE (source_dir_stats, dest_dir_stats))
{
same = identical_basenames;
if (! same)
{
errno = 0;
long name_max = fpathconf (destdir_fd, _PC_NAME_MAX);
if (name_max < 0)
destdir_errno = errno;
else
same = (name_max <= min_baselen
&& (memcmp (source_basename, dest_basename, name_max)
== 0));
}
}
close (destdir_fd);
if (destdir_errno != 0)
{
/* Shouldn't happen. */
error (1, destdir_errno, "%s", dest_dirname);
}
#else
if (fstatat (dest_dfd, dest_dirname, &dest_dir_stats, flags) != 0)
{
/* Shouldn't happen. */
error (1, errno, "%s", dest_dirname);
}
same = SAME_INODE (source_dir_stats, dest_dir_stats);
#endif
free (dest_dirname);
}
return same;
}
|
