]> git.ipfire.org Git - thirdparty/glibc.git/blame - io/fcntl.h
Fix Linux fcntl OFD locks for non-LFS architectures (BZ#20251)
[thirdparty/glibc.git] / io / fcntl.h
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688903eb 1/* Copyright (C) 1991-2018 Free Software Foundation, Inc.
54d79e99 2 This file is part of the GNU C Library.
28f540f4 3
54d79e99 4 The GNU C Library is free software; you can redistribute it and/or
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5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
28f540f4 8
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9 The GNU C Library 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 GNU
41bdb6e2 12 Lesser General Public License for more details.
28f540f4 13
41bdb6e2 14 You should have received a copy of the GNU Lesser General Public
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15 License along with the GNU C Library; if not, see
16 <http://www.gnu.org/licenses/>. */
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17
18/*
19 * POSIX Standard: 6.5 File Control Operations <fcntl.h>
20 */
21
22#ifndef _FCNTL_H
28f540f4 23#define _FCNTL_H 1
5107cf1d 24
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25#include <features.h>
26
5107cf1d 27/* This must be early so <bits/fcntl.h> can define types winningly. */
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28__BEGIN_DECLS
29
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30/* Get __mode_t, __dev_t and __off_t .*/
31#include <bits/types.h>
32
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33/* Get the definitions of O_*, F_*, FD_*: all the
34 numbers and flag bits for `open', `fcntl', et al. */
5107cf1d 35#include <bits/fcntl.h>
28f540f4 36
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37/* Detect if open needs mode as a third argument (or for openat as a fourth
38 argument). */
39#ifdef __O_TMPFILE
40# define __OPEN_NEEDS_MODE(oflag) \
41 (((oflag) & O_CREAT) != 0 || ((oflag) & __O_TMPFILE) == __O_TMPFILE)
42#else
43# define __OPEN_NEEDS_MODE(oflag) (((oflag) & O_CREAT) != 0)
44#endif
45
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46/* POSIX.1-2001 specifies that these types are defined by <fcntl.h>.
47 Earlier POSIX standards permitted any type ending in `_t' to be defined
48 by any POSIX header, so we don't conditionalize the definitions here. */
49#ifndef __mode_t_defined
f42d41d1 50typedef __mode_t mode_t;
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51# define __mode_t_defined
52#endif
f42d41d1 53
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54#ifndef __off_t_defined
55# ifndef __USE_FILE_OFFSET64
f42d41d1 56typedef __off_t off_t;
3a8db22f 57# else
f42d41d1 58typedef __off64_t off_t;
f42d41d1 59# endif
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60# define __off_t_defined
61#endif
62
63#if defined __USE_LARGEFILE64 && !defined __off64_t_defined
64typedef __off64_t off64_t;
65# define __off64_t_defined
66#endif
f42d41d1 67
3a8db22f 68#ifndef __pid_t_defined
f42d41d1 69typedef __pid_t pid_t;
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70# define __pid_t_defined
71#endif
f42d41d1 72
6077fe6e 73/* For XPG all symbols from <sys/stat.h> should also be available. */
35281b18 74#ifdef __USE_XOPEN2K8
05b68e14 75# include <bits/types/struct_timespec.h>
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76#endif
77#if defined __USE_XOPEN || defined __USE_XOPEN2K8
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78# include <bits/stat.h>
79
80# define S_IFMT __S_IFMT
81# define S_IFDIR __S_IFDIR
82# define S_IFCHR __S_IFCHR
83# define S_IFBLK __S_IFBLK
84# define S_IFREG __S_IFREG
85# ifdef __S_IFIFO
86# define S_IFIFO __S_IFIFO
87# endif
88# ifdef __S_IFLNK
89# define S_IFLNK __S_IFLNK
90# endif
91# if (defined __USE_UNIX98 || defined __USE_XOPEN2K8) && defined __S_IFSOCK
92# define S_IFSOCK __S_IFSOCK
93# endif
94
95/* Protection bits. */
96
97# define S_ISUID __S_ISUID /* Set user ID on execution. */
98# define S_ISGID __S_ISGID /* Set group ID on execution. */
99
ed9a38e2 100# if defined __USE_MISC || defined __USE_XOPEN
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101/* Save swapped text after use (sticky bit). This is pretty well obsolete. */
102# define S_ISVTX __S_ISVTX
103# endif
104
105# define S_IRUSR __S_IREAD /* Read by owner. */
106# define S_IWUSR __S_IWRITE /* Write by owner. */
107# define S_IXUSR __S_IEXEC /* Execute by owner. */
108/* Read, write, and execute by owner. */
109# define S_IRWXU (__S_IREAD|__S_IWRITE|__S_IEXEC)
110
111# define S_IRGRP (S_IRUSR >> 3) /* Read by group. */
112# define S_IWGRP (S_IWUSR >> 3) /* Write by group. */
113# define S_IXGRP (S_IXUSR >> 3) /* Execute by group. */
114/* Read, write, and execute by group. */
115# define S_IRWXG (S_IRWXU >> 3)
116
117# define S_IROTH (S_IRGRP >> 3) /* Read by others. */
118# define S_IWOTH (S_IWGRP >> 3) /* Write by others. */
119# define S_IXOTH (S_IXGRP >> 3) /* Execute by others. */
120/* Read, write, and execute by others. */
121# define S_IRWXO (S_IRWXG >> 3)
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122#endif
123
28f540f4 124#ifdef __USE_MISC
dfd2257a 125# ifndef R_OK /* Verbatim from <unistd.h>. Ugh. */
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126/* Values for the second argument to access.
127 These may be OR'd together. */
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128# define R_OK 4 /* Test for read permission. */
129# define W_OK 2 /* Test for write permission. */
130# define X_OK 1 /* Test for execute permission. */
131# define F_OK 0 /* Test for existence. */
132# endif
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133#endif /* Use misc. */
134
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135/* XPG wants the following symbols. <stdio.h> has the same definitions. */
136#if defined __USE_XOPEN || defined __USE_XOPEN2K8
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137# define SEEK_SET 0 /* Seek from beginning of file. */
138# define SEEK_CUR 1 /* Seek from current position. */
139# define SEEK_END 2 /* Seek from end of file. */
140#endif /* XPG */
141
0d217f40 142/* The constants AT_REMOVEDIR and AT_EACCESS have the same value. AT_EACCESS
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143 is meaningful only to faccessat, while AT_REMOVEDIR is meaningful only to
144 unlinkat. The two functions do completely different things and therefore,
145 the flags can be allowed to overlap. For example, passing AT_REMOVEDIR to
146 faccessat would be undefined behavior and thus treating it equivalent to
147 AT_EACCESS is valid undefined behavior. */
0b8f25bb 148#ifdef __USE_ATFILE
26cec518 149# define AT_FDCWD -100 /* Special value used to indicate
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150 the *at functions should use the
151 current working directory. */
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152# define AT_SYMLINK_NOFOLLOW 0x100 /* Do not follow symbolic links. */
153# define AT_REMOVEDIR 0x200 /* Remove directory instead of
154 unlinking file. */
c804fb5f 155# define AT_SYMLINK_FOLLOW 0x400 /* Follow symbolic links. */
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156# ifdef __USE_GNU
157# define AT_NO_AUTOMOUNT 0x800 /* Suppress terminal automount
620a0529 158 traversal. */
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159# define AT_EMPTY_PATH 0x1000 /* Allow empty relative pathname. */
160# endif
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161# define AT_EACCESS 0x200 /* Test access permitted for
162 effective IDs, not real IDs. */
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163#endif
164
28f540f4 165/* Do the file control operation described by CMD on FD.
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166 The remaining arguments are interpreted depending on CMD.
167
168 This function is a cancellation point and therefore not marked with
169 __THROW. */
06ab719d 170#ifndef __USE_FILE_OFFSET64
2c008571 171extern int fcntl (int __fd, int __cmd, ...);
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172#else
173# ifdef __REDIRECT
174extern int __REDIRECT (fcntl, (int __fd, int __cmd, ...), fcntl64);
175# else
176# define fcntl fcntl64
177# endif
178#endif
179#ifdef __USE_LARGEFILE64
180extern int fcntl64 (int __fd, int __cmd, ...);
181#endif
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182
183/* Open FILE and return a new file descriptor for it, or -1 on error.
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184 OFLAG determines the type of access used. If O_CREAT or O_TMPFILE is set
185 in OFLAG, the third argument is taken as a `mode_t', the mode of the
186 created file.
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187
188 This function is a cancellation point and therefore not marked with
189 __THROW. */
dfd2257a 190#ifndef __USE_FILE_OFFSET64
a784e502 191extern int open (const char *__file, int __oflag, ...) __nonnull ((1));
dfd2257a 192#else
918b9d72 193# ifdef __REDIRECT
a784e502 194extern int __REDIRECT (open, (const char *__file, int __oflag, ...), open64)
8a1f658b 195 __nonnull ((1));
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196# else
197# define open open64
198# endif
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199#endif
200#ifdef __USE_LARGEFILE64
a784e502 201extern int open64 (const char *__file, int __oflag, ...) __nonnull ((1));
dfd2257a 202#endif
28f540f4 203
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204#ifdef __USE_ATFILE
205/* Similar to `open' but a relative path name is interpreted relative to
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206 the directory for which FD is a descriptor.
207
0b8f25bb 208 NOTE: some other `openat' implementation support additional functionality
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209 through this interface, especially using the O_XATTR flag. This is not
210 yet supported here.
211
212 This function is a cancellation point and therefore not marked with
213 __THROW. */
214# ifndef __USE_FILE_OFFSET64
a784e502 215extern int openat (int __fd, const char *__file, int __oflag, ...)
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216 __nonnull ((2));
217# else
218# ifdef __REDIRECT
a784e502 219extern int __REDIRECT (openat, (int __fd, const char *__file, int __oflag,
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220 ...), openat64) __nonnull ((2));
221# else
222# define openat openat64
223# endif
224# endif
f095bb72 225# ifdef __USE_LARGEFILE64
a784e502 226extern int openat64 (int __fd, const char *__file, int __oflag, ...)
4973cbe5 227 __nonnull ((2));
f095bb72 228# endif
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229#endif
230
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231/* Create and open FILE, with mode MODE. This takes an `int' MODE
232 argument because that is what `mode_t' will be widened to.
233
234 This function is a cancellation point and therefore not marked with
235 __THROW. */
dfd2257a 236#ifndef __USE_FILE_OFFSET64
3a8db22f 237extern int creat (const char *__file, mode_t __mode) __nonnull ((1));
dfd2257a 238#else
918b9d72 239# ifdef __REDIRECT
3a8db22f 240extern int __REDIRECT (creat, (const char *__file, mode_t __mode),
8a1f658b 241 creat64) __nonnull ((1));
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242# else
243# define creat creat64
244# endif
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245#endif
246#ifdef __USE_LARGEFILE64
3a8db22f 247extern int creat64 (const char *__file, mode_t __mode) __nonnull ((1));
dfd2257a 248#endif
28f540f4 249
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250#if !defined F_LOCK && (defined __USE_MISC || (defined __USE_XOPEN_EXTENDED \
251 && !defined __USE_POSIX))
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252/* NOTE: These declarations also appear in <unistd.h>; be sure to keep both
253 files consistent. Some systems have them there and some here, and some
254 software depends on the macros being defined without including both. */
255
256/* `lockf' is a simpler interface to the locking facilities of `fcntl'.
257 LEN is always relative to the current file position.
258 The CMD argument is one of the following. */
259
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260# define F_ULOCK 0 /* Unlock a previously locked region. */
261# define F_LOCK 1 /* Lock a region for exclusive use. */
262# define F_TLOCK 2 /* Test and lock a region for exclusive use. */
263# define F_TEST 3 /* Test a region for other processes locks. */
28f540f4 264
dfd2257a 265# ifndef __USE_FILE_OFFSET64
3a8db22f 266extern int lockf (int __fd, int __cmd, off_t __len);
dfd2257a 267# else
b6a2b287 268# ifdef __REDIRECT
8dab36a1 269extern int __REDIRECT (lockf, (int __fd, int __cmd, __off64_t __len), lockf64);
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270# else
271# define lockf lockf64
272# endif
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273# endif
274# ifdef __USE_LARGEFILE64
3a8db22f 275extern int lockf64 (int __fd, int __cmd, off64_t __len);
dfd2257a 276# endif
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277#endif
278
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279#ifdef __USE_XOPEN2K
280/* Advice the system about the expected behaviour of the application with
281 respect to the file associated with FD. */
282# ifndef __USE_FILE_OFFSET64
3a8db22f 283extern int posix_fadvise (int __fd, off_t __offset, off_t __len,
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284 int __advise) __THROW;
285# else
b6a2b287 286 # ifdef __REDIRECT_NTH
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287extern int __REDIRECT_NTH (posix_fadvise, (int __fd, __off64_t __offset,
288 __off64_t __len, int __advise),
289 posix_fadvise64);
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290# else
291# define posix_fadvise posix_fadvise64
292# endif
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293# endif
294# ifdef __USE_LARGEFILE64
3a8db22f 295extern int posix_fadvise64 (int __fd, off64_t __offset, off64_t __len,
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296 int __advise) __THROW;
297# endif
298
299
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300/* Reserve storage for the data of the file associated with FD.
301
4c1423ed 302 This function is a possible cancellation point and therefore not
73299943 303 marked with __THROW. */
bb8e0116 304# ifndef __USE_FILE_OFFSET64
3a8db22f 305extern int posix_fallocate (int __fd, off_t __offset, off_t __len);
bb8e0116 306# else
b6a2b287 307 # ifdef __REDIRECT
bb8e0116 308extern int __REDIRECT (posix_fallocate, (int __fd, __off64_t __offset,
089d05d5 309 __off64_t __len),
bb8e0116 310 posix_fallocate64);
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311# else
312# define posix_fallocate posix_fallocate64
313# endif
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314# endif
315# ifdef __USE_LARGEFILE64
3a8db22f 316extern int posix_fallocate64 (int __fd, off64_t __offset, off64_t __len);
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317# endif
318#endif
319
ddfd0535 320
3a50811c 321/* Define some inlines helping to catch common problems. */
5ac3ea17 322#if __USE_FORTIFY_LEVEL > 0 && defined __fortify_function \
3a50811c 323 && defined __va_arg_pack_len
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324# include <bits/fcntl2.h>
325#endif
326
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327__END_DECLS
328
329#endif /* fcntl.h */