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glibc/io/fcntl.h
Adhemerval Zanella a4ed0471d7 Always define __USE_TIME_BITS64 when 64 bit time_t is used 
It was raised on libc-help [1] that some Linux kernel interfaces expect
the libc to define __USE_TIME_BITS64 to indicate the time_t size for the
kABI.  Different than defined by the initial y2038 design document [2],
the __USE_TIME_BITS64 is only defined for ABIs that support more than
one time_t size (by defining the _TIME_BITS for each module).

The 64 bit time_t redirects are now enabled using a different internal
define (__USE_TIME64_REDIRECTS). There is no expected change in semantic
or code generation.

Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu, and
arm-linux-gnueabi

[1] https://sourceware.org/pipermail/libc-help/2024-January/006557.html
[2] https://sourceware.org/glibc/wiki/Y2038ProofnessDesign

Reviewed-by: DJ Delorie <dj@redhat.com>
2024-04-02 15:28:36 -03:00

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/* Copyright (C) 1991-2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
/*
* POSIX Standard: 6.5 File Control Operations <fcntl.h>
*/
#ifndef _FCNTL_H
#define _FCNTL_H 1
#include <features.h>
/* This must be early so <bits/fcntl.h> can define types winningly. */
__BEGIN_DECLS
/* Get __mode_t, __dev_t and __off_t .*/
#include <bits/types.h>
/* Get the definitions of O_*, F_*, FD_*: all the
numbers and flag bits for `open', `fcntl', et al. */
#include <bits/fcntl.h>
/* Detect if open needs mode as a third argument (or for openat as a fourth
argument). */
#ifdef __O_TMPFILE
# define __OPEN_NEEDS_MODE(oflag) \
(((oflag) & O_CREAT) != 0 || ((oflag) & __O_TMPFILE) == __O_TMPFILE)
#else
# define __OPEN_NEEDS_MODE(oflag) (((oflag) & O_CREAT) != 0)
#endif
/* POSIX.1-2001 specifies that these types are defined by <fcntl.h>.
Earlier POSIX standards permitted any type ending in `_t' to be defined
by any POSIX header, so we don't conditionalize the definitions here. */
#ifndef __mode_t_defined
typedef __mode_t mode_t;
# define __mode_t_defined
#endif
#ifndef __off_t_defined
# ifndef __USE_FILE_OFFSET64
typedef __off_t off_t;
# else
typedef __off64_t off_t;
# endif
# define __off_t_defined
#endif
#if defined __USE_LARGEFILE64 && !defined __off64_t_defined
typedef __off64_t off64_t;
# define __off64_t_defined
#endif
#ifndef __pid_t_defined
typedef __pid_t pid_t;
# define __pid_t_defined
#endif
/* For XPG all symbols from <sys/stat.h> should also be available. */
#ifdef __USE_XOPEN2K8
# include <bits/types/struct_timespec.h>
#endif
#if defined __USE_XOPEN || defined __USE_XOPEN2K8
# include <bits/stat.h>
# define S_IFMT __S_IFMT
# define S_IFDIR __S_IFDIR
# define S_IFCHR __S_IFCHR
# define S_IFBLK __S_IFBLK
# define S_IFREG __S_IFREG
# ifdef __S_IFIFO
# define S_IFIFO __S_IFIFO
# endif
# ifdef __S_IFLNK
# define S_IFLNK __S_IFLNK
# endif
# if (defined __USE_UNIX98 || defined __USE_XOPEN2K8) && defined __S_IFSOCK
# define S_IFSOCK __S_IFSOCK
# endif
/* Protection bits. */
# define S_ISUID __S_ISUID /* Set user ID on execution. */
# define S_ISGID __S_ISGID /* Set group ID on execution. */
# if defined __USE_MISC || defined __USE_XOPEN
/* Save swapped text after use (sticky bit). This is pretty well obsolete. */
# define S_ISVTX __S_ISVTX
# endif
# define S_IRUSR __S_IREAD /* Read by owner. */
# define S_IWUSR __S_IWRITE /* Write by owner. */
# define S_IXUSR __S_IEXEC /* Execute by owner. */
/* Read, write, and execute by owner. */
# define S_IRWXU (__S_IREAD|__S_IWRITE|__S_IEXEC)
# define S_IRGRP (S_IRUSR >> 3) /* Read by group. */
# define S_IWGRP (S_IWUSR >> 3) /* Write by group. */
# define S_IXGRP (S_IXUSR >> 3) /* Execute by group. */
/* Read, write, and execute by group. */
# define S_IRWXG (S_IRWXU >> 3)
# define S_IROTH (S_IRGRP >> 3) /* Read by others. */
# define S_IWOTH (S_IWGRP >> 3) /* Write by others. */
# define S_IXOTH (S_IXGRP >> 3) /* Execute by others. */
/* Read, write, and execute by others. */
# define S_IRWXO (S_IRWXG >> 3)
#endif
#ifdef __USE_MISC
# ifndef R_OK /* Verbatim from <unistd.h>. Ugh. */
/* Values for the second argument to access.
These may be OR'd together. */
# define R_OK 4 /* Test for read permission. */
# define W_OK 2 /* Test for write permission. */
# define X_OK 1 /* Test for execute permission. */
# define F_OK 0 /* Test for existence. */
# endif
#endif /* Use misc. */
/* XPG wants the following symbols. <stdio.h> has the same definitions. */
#if defined __USE_XOPEN || defined __USE_XOPEN2K8
# define SEEK_SET 0 /* Seek from beginning of file. */
# define SEEK_CUR 1 /* Seek from current position. */
# define SEEK_END 2 /* Seek from end of file. */
#endif /* XPG */
/* The constants AT_REMOVEDIR and AT_EACCESS have the same value. AT_EACCESS
is meaningful only to faccessat, while AT_REMOVEDIR is meaningful only to
unlinkat. The two functions do completely different things and therefore,
the flags can be allowed to overlap. For example, passing AT_REMOVEDIR to
faccessat would be undefined behavior and thus treating it equivalent to
AT_EACCESS is valid undefined behavior. */
#ifdef __USE_ATFILE
# define AT_FDCWD -100 /* Special value used to indicate
the *at functions should use the
current working directory. */
# define AT_SYMLINK_NOFOLLOW 0x100 /* Do not follow symbolic links. */
# define AT_REMOVEDIR 0x200 /* Remove directory instead of
unlinking file. */
# define AT_SYMLINK_FOLLOW 0x400 /* Follow symbolic links. */
# ifdef __USE_GNU
# define AT_NO_AUTOMOUNT 0x800 /* Suppress terminal automount
traversal. */
# define AT_EMPTY_PATH 0x1000 /* Allow empty relative pathname. */
# define AT_STATX_SYNC_TYPE 0x6000
# define AT_STATX_SYNC_AS_STAT 0x0000
# define AT_STATX_FORCE_SYNC 0x2000
# define AT_STATX_DONT_SYNC 0x4000
# define AT_RECURSIVE 0x8000 /* Apply to the entire subtree. */
# endif
# define AT_EACCESS 0x200 /* Test access permitted for
effective IDs, not real IDs. */
#endif
/* Do the file control operation described by CMD on FD.
The remaining arguments are interpreted depending on CMD.
This function is a cancellation point and therefore not marked with
__THROW. */
#ifndef __USE_TIME64_REDIRECTS
# ifndef __USE_FILE_OFFSET64
extern int fcntl (int __fd, int __cmd, ...);
# else
# ifdef __REDIRECT
extern int __REDIRECT (fcntl, (int __fd, int __cmd, ...), fcntl64);
# else
# define fcntl fcntl64
# endif
# endif
# ifdef __USE_LARGEFILE64
extern int fcntl64 (int __fd, int __cmd, ...);
# endif
#else /* __USE_TIME64_REDIRECTS */
# ifdef __REDIRECT
extern int __REDIRECT_NTH (fcntl, (int __fd, int __request, ...),
__fcntl_time64);
extern int __REDIRECT_NTH (fcntl64, (int __fd, int __request, ...),
__fcntl_time64);
# else
extern int __fcntl_time64 (int __fd, int __request, ...) __THROW;
# define fcntl64 __fcntl_time64
# define fcntl __fcntl_time64
# endif
#endif
/* Open FILE and return a new file descriptor for it, or -1 on error.
OFLAG determines the type of access used. If O_CREAT or O_TMPFILE is set
in OFLAG, the third argument is taken as a `mode_t', the mode of the
created file.
This function is a cancellation point and therefore not marked with
__THROW. */
#ifndef __USE_FILE_OFFSET64
extern int open (const char *__file, int __oflag, ...) __nonnull ((1));
#else
# ifdef __REDIRECT
extern int __REDIRECT (open, (const char *__file, int __oflag, ...), open64)
__nonnull ((1));
# else
# define open open64
# endif
#endif
#ifdef __USE_LARGEFILE64
extern int open64 (const char *__file, int __oflag, ...) __nonnull ((1));
#endif
#ifdef __USE_ATFILE
/* Similar to `open' but a relative path name is interpreted relative to
the directory for which FD is a descriptor.
NOTE: some other `openat' implementation support additional functionality
through this interface, especially using the O_XATTR flag. This is not
yet supported here.
This function is a cancellation point and therefore not marked with
__THROW. */
# ifndef __USE_FILE_OFFSET64
extern int openat (int __fd, const char *__file, int __oflag, ...)
__nonnull ((2));
# else
# ifdef __REDIRECT
extern int __REDIRECT (openat, (int __fd, const char *__file, int __oflag,
...), openat64) __nonnull ((2));
# else
# define openat openat64
# endif
# endif
# ifdef __USE_LARGEFILE64
extern int openat64 (int __fd, const char *__file, int __oflag, ...)
__nonnull ((2));
# endif
#endif
/* Create and open FILE, with mode MODE. This takes an `int' MODE
argument because that is what `mode_t' will be widened to.
This function is a cancellation point and therefore not marked with
__THROW. */
#ifndef __USE_FILE_OFFSET64
extern int creat (const char *__file, mode_t __mode) __nonnull ((1));
#else
# ifdef __REDIRECT
extern int __REDIRECT (creat, (const char *__file, mode_t __mode),
creat64) __nonnull ((1));
# else
# define creat creat64
# endif
#endif
#ifdef __USE_LARGEFILE64
extern int creat64 (const char *__file, mode_t __mode) __nonnull ((1));
#endif
#if !defined F_LOCK && (defined __USE_MISC || (defined __USE_XOPEN_EXTENDED \
&& !defined __USE_POSIX))
/* NOTE: These declarations also appear in <unistd.h>; be sure to keep both
files consistent. Some systems have them there and some here, and some
software depends on the macros being defined without including both. */
/* `lockf' is a simpler interface to the locking facilities of `fcntl'.
LEN is always relative to the current file position.
The CMD argument is one of the following. */
# define F_ULOCK 0 /* Unlock a previously locked region. */
# define F_LOCK 1 /* Lock a region for exclusive use. */
# define F_TLOCK 2 /* Test and lock a region for exclusive use. */
# define F_TEST 3 /* Test a region for other processes locks. */
# ifndef __USE_FILE_OFFSET64
extern int lockf (int __fd, int __cmd, off_t __len);
# else
# ifdef __REDIRECT
extern int __REDIRECT (lockf, (int __fd, int __cmd, __off64_t __len), lockf64);
# else
# define lockf lockf64
# endif
# endif
# ifdef __USE_LARGEFILE64
extern int lockf64 (int __fd, int __cmd, off64_t __len);
# endif
#endif
#ifdef __USE_XOPEN2K
/* Advice the system about the expected behaviour of the application with
respect to the file associated with FD. */
# ifndef __USE_FILE_OFFSET64
extern int posix_fadvise (int __fd, off_t __offset, off_t __len,
int __advise) __THROW;
# else
# ifdef __REDIRECT_NTH
extern int __REDIRECT_NTH (posix_fadvise, (int __fd, __off64_t __offset,
__off64_t __len, int __advise),
posix_fadvise64);
# else
# define posix_fadvise posix_fadvise64
# endif
# endif
# ifdef __USE_LARGEFILE64
extern int posix_fadvise64 (int __fd, off64_t __offset, off64_t __len,
int __advise) __THROW;
# endif
/* Reserve storage for the data of the file associated with FD.
This function is a possible cancellation point and therefore not
marked with __THROW. */
# ifndef __USE_FILE_OFFSET64
extern int posix_fallocate (int __fd, off_t __offset, off_t __len);
# else
# ifdef __REDIRECT
extern int __REDIRECT (posix_fallocate, (int __fd, __off64_t __offset,
__off64_t __len),
posix_fallocate64);
# else
# define posix_fallocate posix_fallocate64
# endif
# endif
# ifdef __USE_LARGEFILE64
extern int posix_fallocate64 (int __fd, off64_t __offset, off64_t __len);
# endif
#endif
/* Define some inlines helping to catch common problems. */
#if __USE_FORTIFY_LEVEL > 0 && defined __fortify_function
# include <bits/fcntl2.h>
#endif
__END_DECLS
#endif /* fcntl.h */
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