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, ...)
44 va_start (arg, flags);
46 /* If mode_t is narrower than int, use the promoted type (int),
47 not mode_t. Use sizeof to guess whether mode_t is narrower;
48 we don't know of any practical counterexamples. */
49 mode = (sizeof (mode_t) < sizeof (int)
51 : va_arg (arg, mode_t));
56 # if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
57 if (strcmp (filename, "/dev/null") == 0)
61 # if OPEN_TRAILING_SLASH_BUG
62 /* If the filename ends in a slash and one of O_CREAT, O_WRONLY, O_RDWR
63 is specified, then fail.
64 Rationale: POSIX <http://www.opengroup.org/susv3/basedefs/xbd_chap04.html>
66 "A pathname that contains at least one non-slash character and that
67 ends with one or more trailing slashes shall be resolved as if a
68 single dot character ( '.' ) were appended to the pathname."
70 "The special filename dot shall refer to the directory specified by
72 If the named file already exists as a directory, then
73 - if O_CREAT is specified, open() must fail because of the semantics
75 - if O_WRONLY or O_RDWR is specified, open() must fail because POSIX
76 <http://www.opengroup.org/susv3/functions/open.html> says that it
77 fails with errno = EISDIR in this case.
78 If the named file does not exist or does not name a directory, then
79 - if O_CREAT is specified, open() must fail since open() cannot create
81 - if O_WRONLY or O_RDWR is specified, open() must fail because the
82 file does not contain a '.' directory. */
83 if (flags & (O_CREAT | O_WRONLY | O_RDWR))
85 size_t len = strlen (filename);
86 if (len > 0 && filename[len - 1] == '/')
94 fd = open (filename, flags, mode);
96 # if OPEN_TRAILING_SLASH_BUG
97 /* If the filename ends in a slash and fd does not refer to a directory,
99 Rationale: POSIX <http://www.opengroup.org/susv3/basedefs/xbd_chap04.html>
101 "A pathname that contains at least one non-slash character and that
102 ends with one or more trailing slashes shall be resolved as if a
103 single dot character ( '.' ) were appended to the pathname."
105 "The special filename dot shall refer to the directory specified by
107 If the named file without the slash is not a directory, open() must fail
111 size_t len = strlen (filename);
112 if (len > 0 && filename[len - 1] == '/')
116 if (fstat (fd, &statbuf) >= 0 && !S_ISDIR (statbuf.st_mode))