1 /* -*- buffer-read-only: t -*- vi: set ro: */
2 /* DO NOT EDIT! GENERATED AUTOMATICALLY! */
3 /* provide a replacement openat function
4 Copyright (C) 2004-2011 Free Software Foundation, Inc.
6 This program is free software: you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>. */
19 /* written by Jim Meyering */
30 #include "dosname.h" /* solely for definition of IS_ABSOLUTE_FILE_NAME */
31 #include "openat-priv.h"
38 /* Like openat, but work around Solaris 9 bugs with trailing slash. */
40 rpl_openat (int dfd, char const *filename, int flags, ...)
49 va_start (arg, flags);
51 /* We have to use PROMOTED_MODE_T instead of mode_t, otherwise GCC 4
52 creates crashing code when 'mode_t' is smaller than 'int'. */
53 mode = va_arg (arg, PROMOTED_MODE_T);
58 # if OPEN_TRAILING_SLASH_BUG
59 /* If the filename ends in a slash and one of O_CREAT, O_WRONLY, O_RDWR
60 is specified, then fail.
61 Rationale: POSIX <http://www.opengroup.org/susv3/basedefs/xbd_chap04.html>
63 "A pathname that contains at least one non-slash character and that
64 ends with one or more trailing slashes shall be resolved as if a
65 single dot character ( '.' ) were appended to the pathname."
67 "The special filename dot shall refer to the directory specified by
69 If the named file already exists as a directory, then
70 - if O_CREAT is specified, open() must fail because of the semantics
72 - if O_WRONLY or O_RDWR is specified, open() must fail because POSIX
73 <http://www.opengroup.org/susv3/functions/open.html> says that it
74 fails with errno = EISDIR in this case.
75 If the named file does not exist or does not name a directory, then
76 - if O_CREAT is specified, open() must fail since open() cannot create
78 - if O_WRONLY or O_RDWR is specified, open() must fail because the
79 file does not contain a '.' directory. */
80 if (flags & (O_CREAT | O_WRONLY | O_RDWR))
82 size_t len = strlen (filename);
83 if (len > 0 && filename[len - 1] == '/')
91 fd = openat (dfd, filename, flags, mode);
93 # if OPEN_TRAILING_SLASH_BUG
94 /* If the filename ends in a slash and fd does not refer to a directory,
96 Rationale: POSIX <http://www.opengroup.org/susv3/basedefs/xbd_chap04.html>
98 "A pathname that contains at least one non-slash character and that
99 ends with one or more trailing slashes shall be resolved as if a
100 single dot character ( '.' ) were appended to the pathname."
102 "The special filename dot shall refer to the directory specified by
104 If the named file without the slash is not a directory, open() must fail
108 /* We know len is positive, since open did not fail with ENOENT. */
109 size_t len = strlen (filename);
110 if (filename[len - 1] == '/')
114 if (fstat (fd, &statbuf) >= 0 && !S_ISDIR (statbuf.st_mode))
127 #else /* !HAVE_OPENAT */
129 /* Replacement for Solaris' openat function.
130 <http://www.google.com/search?q=openat+site:docs.sun.com>
131 First, try to simulate it via open ("/proc/self/fd/FD/FILE").
132 Failing that, simulate it by doing save_cwd/fchdir/open/restore_cwd.
133 If either the save_cwd or the restore_cwd fails (relatively unlikely),
134 then give a diagnostic and exit nonzero.
135 Otherwise, upon failure, set errno and return -1, as openat does.
136 Upon successful completion, return a file descriptor. */
138 openat (int fd, char const *file, int flags, ...)
145 va_start (arg, flags);
147 /* We have to use PROMOTED_MODE_T instead of mode_t, otherwise GCC 4
148 creates crashing code when 'mode_t' is smaller than 'int'. */
149 mode = va_arg (arg, PROMOTED_MODE_T);
154 return openat_permissive (fd, file, flags, mode, NULL);
157 /* Like openat (FD, FILE, FLAGS, MODE), but if CWD_ERRNO is
158 nonnull, set *CWD_ERRNO to an errno value if unable to save
159 or restore the initial working directory. This is needed only
160 the first time remove.c's remove_dir opens a command-line
163 If a previous attempt to restore the current working directory
164 failed, then we must not even try to access a `.'-relative name.
165 It is the caller's responsibility not to call this function
169 openat_permissive (int fd, char const *file, int flags, mode_t mode,
172 struct saved_cwd saved_cwd;
177 if (fd == AT_FDCWD || IS_ABSOLUTE_FILE_NAME (file))
178 return open (file, flags, mode);
181 char buf[OPENAT_BUFFER_SIZE];
182 char *proc_file = openat_proc_name (buf, fd, file);
185 int open_result = open (proc_file, flags, mode);
186 int open_errno = errno;
187 if (proc_file != buf)
189 /* If the syscall succeeds, or if it fails with an unexpected
190 errno value, then return right away. Otherwise, fall through
191 and resort to using save_cwd/restore_cwd. */
192 if (0 <= open_result || ! EXPECTED_ERRNO (open_errno))
200 save_ok = (save_cwd (&saved_cwd) == 0);
204 openat_save_fail (errno);
207 if (0 <= fd && fd == saved_cwd.desc)
209 /* If saving the working directory collides with the user's
210 requested fd, then the user's fd must have been closed to
212 free_cwd (&saved_cwd);
222 err = open (file, flags, mode);
224 if (save_ok && restore_cwd (&saved_cwd) != 0)
228 /* Don't write a message to just-created fd 2. */
230 if (err == STDERR_FILENO)
232 openat_restore_fail (saved_errno);
238 free_cwd (&saved_cwd);
243 /* Return true if our openat implementation must resort to
244 using save_cwd and restore_cwd. */
246 openat_needs_fchdir (void)
248 bool needs_fchdir = true;
249 int fd = open ("/", O_SEARCH);
253 char buf[OPENAT_BUFFER_SIZE];
254 char *proc_file = openat_proc_name (buf, fd, ".");
257 needs_fchdir = false;
258 if (proc_file != buf)
267 #endif /* !HAVE_OPENAT */