1 /* Open a descriptor to a file.
2 Copyright (C) 2007-2009 Free Software Foundation, Inc.
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 3 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>. */
17 /* Written by Bruno Haible <bruno@clisp.org>, 2007. */
21 /* Get the original definition of open. It might be defined as a macro. */
22 #define __need_system_fcntl_h
24 #undef __need_system_fcntl_h
25 #include <sys/types.h>
28 orig_open (const char *filename, int flags, mode_t mode)
30 return open (filename, flags, mode);
39 #include <sys/types.h>
42 #ifndef REPLACE_OPEN_DIRECTORY
43 # define REPLACE_OPEN_DIRECTORY 0
47 open (const char *filename, int flags, ...)
56 va_start (arg, flags);
58 /* We have to use PROMOTED_MODE_T instead of mode_t, otherwise GCC 4
59 creates crashing code when 'mode_t' is smaller than 'int'. */
60 mode = va_arg (arg, PROMOTED_MODE_T);
65 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
66 if (strcmp (filename, "/dev/null") == 0)
70 #if OPEN_TRAILING_SLASH_BUG
71 /* If the filename ends in a slash and one of O_CREAT, O_WRONLY, O_RDWR
72 is specified, then fail.
73 Rationale: POSIX <http://www.opengroup.org/susv3/basedefs/xbd_chap04.html>
75 "A pathname that contains at least one non-slash character and that
76 ends with one or more trailing slashes shall be resolved as if a
77 single dot character ( '.' ) were appended to the pathname."
79 "The special filename dot shall refer to the directory specified by
81 If the named file already exists as a directory, then
82 - if O_CREAT is specified, open() must fail because of the semantics
84 - if O_WRONLY or O_RDWR is specified, open() must fail because POSIX
85 <http://www.opengroup.org/susv3/functions/open.html> says that it
86 fails with errno = EISDIR in this case.
87 If the named file does not exist or does not name a directory, then
88 - if O_CREAT is specified, open() must fail since open() cannot create
90 - if O_WRONLY or O_RDWR is specified, open() must fail because the
91 file does not contain a '.' directory. */
92 if (flags & (O_CREAT | O_WRONLY | O_RDWR))
94 size_t len = strlen (filename);
95 if (len > 0 && filename[len - 1] == '/')
103 fd = orig_open (filename, flags, mode);
105 #ifdef FCHDIR_REPLACEMENT
106 /* Implementing fchdir and fdopendir requires the ability to open a
107 directory file descriptor. If open doesn't support that (as on
108 mingw), we use a dummy file that behaves the same as directories
109 on Linux (ie. always reports EOF on attempts to read()), and
110 override fstat() in fchdir.c to hide the fact that we have a
112 if (REPLACE_OPEN_DIRECTORY && fd < 0 && errno == EACCES
113 && (mode & O_ACCMODE) == O_RDONLY)
116 if (stat (filename, &statbuf) == 0 && S_ISDIR (statbuf.st_mode))
118 /* Maximum recursion depth of 1. */
119 fd = open ("/dev/null", flags, mode);
121 fd = _gl_register_fd (fd, filename);
128 #if OPEN_TRAILING_SLASH_BUG
129 /* If the filename ends in a slash and fd does not refer to a directory,
131 Rationale: POSIX <http://www.opengroup.org/susv3/basedefs/xbd_chap04.html>
133 "A pathname that contains at least one non-slash character and that
134 ends with one or more trailing slashes shall be resolved as if a
135 single dot character ( '.' ) were appended to the pathname."
137 "The special filename dot shall refer to the directory specified by
139 If the named file without the slash is not a directory, open() must fail
143 size_t len = strlen (filename);
144 if (len > 0 && filename[len - 1] == '/')
148 if (fstat (fd, &statbuf) >= 0 && !S_ISDIR (statbuf.st_mode))
158 #ifdef FCHDIR_REPLACEMENT
159 if (!REPLACE_OPEN_DIRECTORY && 0 <= fd)
160 fd = _gl_register_fd (fd, filename);