1 /* Open a descriptor to a file.
2 Copyright (C) 2007-2008 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. */
24 /* If the fchdir replacement is used, open() is defined in fchdir.c. */
25 #ifndef FCHDIR_REPLACEMENT
30 # include <sys/types.h>
31 # include <sys/stat.h>
34 open (const char *filename, int flags, ...)
43 va_start (arg, flags);
45 /* If mode_t is narrower than int, use the promoted type (int),
46 not mode_t. Use sizeof to guess whether mode_t is narrower;
47 we don't know of any practical counterexamples. */
48 mode = (sizeof (mode_t) < sizeof (int)
50 : va_arg (arg, mode_t));
55 # if OPEN_TRAILING_SLASH_BUG
56 /* If the filename ends in a slash and one of O_CREAT, O_WRONLY, O_RDWR
57 is specified, then fail.
58 Rationale: POSIX <http://www.opengroup.org/susv3/basedefs/xbd_chap04.html>
60 "A pathname that contains at least one non-slash character and that
61 ends with one or more trailing slashes shall be resolved as if a
62 single dot character ( '.' ) were appended to the pathname."
64 "The special filename dot shall refer to the directory specified by
66 If the named file already exists as a directory, then
67 - if O_CREAT is specified, open() must fail because of the semantics
69 - if O_WRONLY or O_RDWR is specified, open() must fail because POSIX
70 <http://www.opengroup.org/susv3/functions/open.html> says that it
71 fails with errno = EISDIR in this case.
72 If the named file does not exist or does not name a directory, then
73 - if O_CREAT is specified, open() must fail since open() cannot create
75 - if O_WRONLY or O_RDWR is specified, open() must fail because the
76 file does not contain a '.' directory. */
77 if (flags & (O_CREAT | O_WRONLY | O_RDWR))
79 size_t len = strlen (filename);
80 if (len > 0 && filename[len - 1] == '/')
88 # if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
89 if (strcmp (filename, "/dev/null") == 0)
93 return open (filename, flags, mode);