c675522fc4
provides the correct semantics for flock(2) style locks which are used by the lockf(1) command line tool and the pidfile(3) library. It also implements recovery from server restarts and ensures that dirty cache blocks are written to the server before obtaining locks (allowing multiple clients to use file locking to safely share data). Sponsored by: Isilon Systems PR: 94256 MFC after: 2 weeks
284 lines
9.5 KiB
C
284 lines
9.5 KiB
C
/*-
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* Copyright (c) 1983, 1990, 1993
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* The Regents of the University of California. All rights reserved.
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* (c) UNIX System Laboratories, Inc.
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* All or some portions of this file are derived from material licensed
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* to the University of California by American Telephone and Telegraph
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* Co. or Unix System Laboratories, Inc. and are reproduced herein with
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* the permission of UNIX System Laboratories, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)fcntl.h 8.3 (Berkeley) 1/21/94
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* $FreeBSD$
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*/
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#ifndef _SYS_FCNTL_H_
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#define _SYS_FCNTL_H_
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/*
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* This file includes the definitions for open and fcntl
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* described by POSIX for <fcntl.h>; it also includes
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* related kernel definitions.
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*/
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#include <sys/cdefs.h>
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#include <sys/_types.h>
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#ifndef _MODE_T_DECLARED
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typedef __mode_t mode_t;
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#define _MODE_T_DECLARED
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#endif
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#ifndef _OFF_T_DECLARED
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typedef __off_t off_t;
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#define _OFF_T_DECLARED
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#endif
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#ifndef _PID_T_DECLARED
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typedef __pid_t pid_t;
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#define _PID_T_DECLARED
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#endif
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/*
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* File status flags: these are used by open(2), fcntl(2).
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* They are also used (indirectly) in the kernel file structure f_flags,
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* which is a superset of the open/fcntl flags. Open flags and f_flags
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* are inter-convertible using OFLAGS(fflags) and FFLAGS(oflags).
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* Open/fcntl flags begin with O_; kernel-internal flags begin with F.
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*/
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/* open-only flags */
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#define O_RDONLY 0x0000 /* open for reading only */
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#define O_WRONLY 0x0001 /* open for writing only */
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#define O_RDWR 0x0002 /* open for reading and writing */
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#define O_ACCMODE 0x0003 /* mask for above modes */
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/*
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* Kernel encoding of open mode; separate read and write bits that are
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* independently testable: 1 greater than the above.
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*
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* XXX
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* FREAD and FWRITE are excluded from the #ifdef _KERNEL so that TIOCFLUSH,
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* which was documented to use FREAD/FWRITE, continues to work.
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*/
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#if __BSD_VISIBLE
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#define FREAD 0x0001
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#define FWRITE 0x0002
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#endif
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#define O_NONBLOCK 0x0004 /* no delay */
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#define O_APPEND 0x0008 /* set append mode */
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#if __BSD_VISIBLE
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#define O_SHLOCK 0x0010 /* open with shared file lock */
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#define O_EXLOCK 0x0020 /* open with exclusive file lock */
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#define O_ASYNC 0x0040 /* signal pgrp when data ready */
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#define O_FSYNC 0x0080 /* synchronous writes */
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#endif
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#define O_SYNC 0x0080 /* POSIX synonym for O_FSYNC */
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#if __BSD_VISIBLE
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#define O_NOFOLLOW 0x0100 /* don't follow symlinks */
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#endif
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#define O_CREAT 0x0200 /* create if nonexistent */
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#define O_TRUNC 0x0400 /* truncate to zero length */
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#define O_EXCL 0x0800 /* error if already exists */
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#ifdef _KERNEL
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#define FHASLOCK 0x4000 /* descriptor holds advisory lock */
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#endif
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/* Defined by POSIX Extended API Set Part 2 */
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#if __BSD_VISIBLE
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/*
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* Magic value that specify the use of the current working directory
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* to determine the target of relative file paths in the openat() and
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* similar syscalls.
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*/
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#define AT_FDCWD -100
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/*
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* Miscellaneous flags for the *at() syscalls.
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*/
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#define AT_EACCESS 0x100 /* Check access using effective user and group ID */
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#define AT_SYMLINK_NOFOLLOW 0x200 /* Do not follow symbolic links */
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#define AT_SYMLINK_FOLLOW 0x400 /* Follow symbolic link */
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#define AT_REMOVEDIR 0x800 /* Remove directory instead of file */
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#endif
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/* Defined by POSIX 1003.1; BSD default, but must be distinct from O_RDONLY. */
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#define O_NOCTTY 0x8000 /* don't assign controlling terminal */
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#if __BSD_VISIBLE
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/* Attempt to bypass buffer cache */
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#define O_DIRECT 0x00010000
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#endif
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/* Defined by POSIX Extended API Set Part 2 */
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#if __BSD_VISIBLE
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#define O_DIRECTORY 0x00020000 /* Fail if not directory */
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#define O_EXEC 0x00040000 /* Open for execute only */
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#endif
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#ifdef _KERNEL
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#define FEXEC O_EXEC
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#endif
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/*
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* XXX missing O_DSYNC, O_RSYNC.
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*/
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#ifdef _KERNEL
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/* convert from open() flags to/from fflags; convert O_RD/WR to FREAD/FWRITE */
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#define FFLAGS(oflags) ((oflags) + 1)
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#define OFLAGS(fflags) ((fflags) - 1)
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/* bits to save after open */
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#define FMASK (FREAD|FWRITE|FAPPEND|FASYNC|FFSYNC|FNONBLOCK|O_DIRECT|FEXEC)
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/* bits settable by fcntl(F_SETFL, ...) */
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#define FCNTLFLAGS (FAPPEND|FASYNC|FFSYNC|FNONBLOCK|O_DIRECT)
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#if defined(COMPAT_FREEBSD7) || defined(COMPAT_FREEBSD6) || \
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defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4)
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/*
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* Set by shm_open(3) in older libc's to get automatic MAP_ASYNC
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* behavior for POSIX shared memory objects (which are otherwise
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* implemented as plain files).
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*/
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#define FPOSIXSHM O_NOFOLLOW
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#undef FCNTLFLAGS
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#define FCNTLFLAGS (FAPPEND|FASYNC|FFSYNC|FNONBLOCK|FPOSIXSHM|O_DIRECT)
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#endif
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#endif
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/*
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* The O_* flags used to have only F* names, which were used in the kernel
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* and by fcntl. We retain the F* names for the kernel f_flag field
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* and for backward compatibility for fcntl. These flags are deprecated.
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*/
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#if __BSD_VISIBLE
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#define FAPPEND O_APPEND /* kernel/compat */
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#define FASYNC O_ASYNC /* kernel/compat */
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#define FFSYNC O_FSYNC /* kernel */
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#define FNONBLOCK O_NONBLOCK /* kernel */
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#define FNDELAY O_NONBLOCK /* compat */
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#define O_NDELAY O_NONBLOCK /* compat */
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#endif
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/*
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* We are out of bits in f_flag (which is a short). However,
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* the flag bits not set in FMASK are only meaningful in the
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* initial open syscall. Those bits can thus be given a
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* different meaning for fcntl(2).
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*/
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#if __BSD_VISIBLE
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#endif
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/*
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* Constants used for fcntl(2)
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*/
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/* command values */
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#define F_DUPFD 0 /* duplicate file descriptor */
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#define F_GETFD 1 /* get file descriptor flags */
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#define F_SETFD 2 /* set file descriptor flags */
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#define F_GETFL 3 /* get file status flags */
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#define F_SETFL 4 /* set file status flags */
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#if __BSD_VISIBLE || __XSI_VISIBLE || __POSIX_VISIBLE >= 200112
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#define F_GETOWN 5 /* get SIGIO/SIGURG proc/pgrp */
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#define F_SETOWN 6 /* set SIGIO/SIGURG proc/pgrp */
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#endif
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#define F_OGETLK 7 /* get record locking information */
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#define F_OSETLK 8 /* set record locking information */
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#define F_OSETLKW 9 /* F_SETLK; wait if blocked */
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#define F_DUP2FD 10 /* duplicate file descriptor to arg */
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#define F_GETLK 11 /* get record locking information */
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#define F_SETLK 12 /* set record locking information */
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#define F_SETLKW 13 /* F_SETLK; wait if blocked */
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#define F_SETLK_REMOTE 14 /* debugging support for remote locks */
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/* file descriptor flags (F_GETFD, F_SETFD) */
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#define FD_CLOEXEC 1 /* close-on-exec flag */
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/* record locking flags (F_GETLK, F_SETLK, F_SETLKW) */
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#define F_RDLCK 1 /* shared or read lock */
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#define F_UNLCK 2 /* unlock */
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#define F_WRLCK 3 /* exclusive or write lock */
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#define F_UNLCKSYS 4 /* purge locks for a given system ID */
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#define F_CANCEL 5 /* cancel an async lock request */
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#ifdef _KERNEL
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#define F_WAIT 0x010 /* Wait until lock is granted */
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#define F_FLOCK 0x020 /* Use flock(2) semantics for lock */
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#define F_POSIX 0x040 /* Use POSIX semantics for lock */
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#define F_REMOTE 0x080 /* Lock owner is remote NFS client */
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#define F_NOINTR 0x100 /* Ignore signals when waiting */
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#endif
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/*
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* Advisory file segment locking data type -
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* information passed to system by user
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*/
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struct flock {
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off_t l_start; /* starting offset */
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off_t l_len; /* len = 0 means until end of file */
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pid_t l_pid; /* lock owner */
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short l_type; /* lock type: read/write, etc. */
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short l_whence; /* type of l_start */
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int l_sysid; /* remote system id or zero for local */
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};
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/*
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* Old advisory file segment locking data type,
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* before adding l_sysid.
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*/
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struct oflock {
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off_t l_start; /* starting offset */
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off_t l_len; /* len = 0 means until end of file */
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pid_t l_pid; /* lock owner */
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short l_type; /* lock type: read/write, etc. */
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short l_whence; /* type of l_start */
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};
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#if __BSD_VISIBLE
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/* lock operations for flock(2) */
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#define LOCK_SH 0x01 /* shared file lock */
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#define LOCK_EX 0x02 /* exclusive file lock */
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#define LOCK_NB 0x04 /* don't block when locking */
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#define LOCK_UN 0x08 /* unlock file */
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#endif
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/*
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* XXX missing posix_fadvise() and posix_fallocate(), and POSIX_FADV_* macros.
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*/
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#ifndef _KERNEL
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__BEGIN_DECLS
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int open(const char *, int, ...);
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int creat(const char *, mode_t);
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int fcntl(int, int, ...);
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int openat(int, const char *, int, ...);
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#if __BSD_VISIBLE
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int flock(int, int);
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#endif
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__END_DECLS
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#endif
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#endif /* !_SYS_FCNTL_H_ */
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