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
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
|
/* Open a descriptor to a file.
Copyright (C) 2007-2011 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 <http://www.gnu.org/licenses/>. */
/* Written by Bruno Haible <bruno@clisp.org>, 2007. */
#include <config.h>
/* Get the original definition of open. It might be defined as a macro. */
#define __need_system_fcntl_h
#include <fcntl.h>
#undef __need_system_fcntl_h
#include <sys/types.h>
static inline int
orig_open (const char *filename, int flags, mode_t mode)
{
return open (filename, flags, mode);
}
/* Specification. */
#include <fcntl.h>
#include <errno.h>
#include <stdarg.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#ifndef REPLACE_OPEN_DIRECTORY
# define REPLACE_OPEN_DIRECTORY 0
#endif
int
open (const char *filename, int flags, ...)
{
mode_t mode;
int fd;
mode = 0;
if (flags & O_CREAT)
{
va_list arg;
va_start (arg, flags);
/* We have to use PROMOTED_MODE_T instead of mode_t, otherwise GCC 4
creates crashing code when 'mode_t' is smaller than 'int'. */
mode = va_arg (arg, PROMOTED_MODE_T);
va_end (arg);
}
#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
if (strcmp (filename, "/dev/null") == 0)
filename = "NUL";
#endif
#if OPEN_TRAILING_SLASH_BUG
/* If the filename ends in a slash and one of O_CREAT, O_WRONLY, O_RDWR
is specified, then fail.
Rationale: POSIX <http://www.opengroup.org/susv3/basedefs/xbd_chap04.html>
says that
"A pathname that contains at least one non-slash character and that
ends with one or more trailing slashes shall be resolved as if a
single dot character ( '.' ) were appended to the pathname."
and
"The special filename dot shall refer to the directory specified by
its predecessor."
If the named file already exists as a directory, then
- if O_CREAT is specified, open() must fail because of the semantics
of O_CREAT,
- if O_WRONLY or O_RDWR is specified, open() must fail because POSIX
<http://www.opengroup.org/susv3/functions/open.html> says that it
fails with errno = EISDIR in this case.
If the named file does not exist or does not name a directory, then
- if O_CREAT is specified, open() must fail since open() cannot create
directories,
- if O_WRONLY or O_RDWR is specified, open() must fail because the
file does not contain a '.' directory. */
if (flags & (O_CREAT | O_WRONLY | O_RDWR))
{
size_t len = strlen (filename);
if (len > 0 && filename[len - 1] == '/')
{
errno = EISDIR;
return -1;
}
}
#endif
fd = orig_open (filename, flags, mode);
#if REPLACE_FCHDIR
/* Implementing fchdir and fdopendir requires the ability to open a
directory file descriptor. If open doesn't support that (as on
mingw), we use a dummy file that behaves the same as directories
on Linux (ie. always reports EOF on attempts to read()), and
override fstat() in fchdir.c to hide the fact that we have a
dummy. */
if (REPLACE_OPEN_DIRECTORY && fd < 0 && errno == EACCES
&& ((flags & O_ACCMODE) == O_RDONLY
|| (O_SEARCH != O_RDONLY && (flags & O_ACCMODE) == O_SEARCH)))
{
struct stat statbuf;
if (stat (filename, &statbuf) == 0 && S_ISDIR (statbuf.st_mode))
{
/* Maximum recursion depth of 1. */
fd = open ("/dev/null", flags, mode);
if (0 <= fd)
fd = _gl_register_fd (fd, filename);
}
else
errno = EACCES;
}
#endif
#if OPEN_TRAILING_SLASH_BUG
/* If the filename ends in a slash and fd does not refer to a directory,
then fail.
Rationale: POSIX <http://www.opengroup.org/susv3/basedefs/xbd_chap04.html>
says that
"A pathname that contains at least one non-slash character and that
ends with one or more trailing slashes shall be resolved as if a
single dot character ( '.' ) were appended to the pathname."
and
"The special filename dot shall refer to the directory specified by
its predecessor."
If the named file without the slash is not a directory, open() must fail
with ENOTDIR. */
if (fd >= 0)
{
/* We know len is positive, since open did not fail with ENOENT. */
size_t len = strlen (filename);
if (filename[len - 1] == '/')
{
struct stat statbuf;
if (fstat (fd, &statbuf) >= 0 && !S_ISDIR (statbuf.st_mode))
{
close (fd);
errno = ENOTDIR;
return -1;
}
}
}
#endif
#if REPLACE_FCHDIR
if (!REPLACE_OPEN_DIRECTORY && 0 <= fd)
fd = _gl_register_fd (fd, filename);
#endif
return fd;
}
|
