freebsd-dev/sys/sys/fcntl.h
Peter Wemm 7e3426aa1f Implement a new open(2) flag: O_NOFOLLOW. This will instruct open
to not follow symlinks, but to open a handle on the link itself(!).
As strange as this might sound, it has several useful applications
safe race-free ways of opening files in hostile areas (eg: /tmp, a mode
1777 /var/mail, etc).  It also would allow things like fchown() to work
on the link rather than having to implement a new syscall specifically for
that task.

Reviewed by: phk
1998-04-06 17:38:43 +00:00

193 lines
7.0 KiB
C

/*-
* Copyright (c) 1983, 1990, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)fcntl.h 8.3 (Berkeley) 1/21/94
* $Id: fcntl.h,v 1.6 1997/02/22 09:45:13 peter Exp $
*/
#ifndef _SYS_FCNTL_H_
#define _SYS_FCNTL_H_
/*
* This file includes the definitions for open and fcntl
* described by POSIX for <fcntl.h>; it also includes
* related kernel definitions.
*/
#ifndef KERNEL
#include <sys/types.h>
#endif
/*
* File status flags: these are used by open(2), fcntl(2).
* They are also used (indirectly) in the kernel file structure f_flags,
* which is a superset of the open/fcntl flags. Open flags and f_flags
* are inter-convertible using OFLAGS(fflags) and FFLAGS(oflags).
* Open/fcntl flags begin with O_; kernel-internal flags begin with F.
*/
/* open-only flags */
#define O_RDONLY 0x0000 /* open for reading only */
#define O_WRONLY 0x0001 /* open for writing only */
#define O_RDWR 0x0002 /* open for reading and writing */
#define O_ACCMODE 0x0003 /* mask for above modes */
/*
* Kernel encoding of open mode; separate read and write bits that are
* independently testable: 1 greater than the above.
*
* XXX
* FREAD and FWRITE are excluded from the #ifdef KERNEL so that TIOCFLUSH,
* which was documented to use FREAD/FWRITE, continues to work.
*/
#ifndef _POSIX_SOURCE
#define FREAD 0x0001
#define FWRITE 0x0002
#endif
#define O_NONBLOCK 0x0004 /* no delay */
#define O_APPEND 0x0008 /* set append mode */
#ifndef _POSIX_SOURCE
#define O_SHLOCK 0x0010 /* open with shared file lock */
#define O_EXLOCK 0x0020 /* open with exclusive file lock */
#define O_ASYNC 0x0040 /* signal pgrp when data ready */
#define O_FSYNC 0x0080 /* synchronous writes */
#define O_NOFOLLOW 0x0100 /* don't follow symlinks */
#endif
#define O_CREAT 0x0200 /* create if nonexistent */
#define O_TRUNC 0x0400 /* truncate to zero length */
#define O_EXCL 0x0800 /* error if already exists */
#ifdef KERNEL
#define FMARK 0x1000 /* mark during gc() */
#define FDEFER 0x2000 /* defer for next gc pass */
#define FHASLOCK 0x4000 /* descriptor holds advisory lock */
#endif
/* Defined by POSIX 1003.1; BSD default, but must be distinct from O_RDONLY. */
#define O_NOCTTY 0x8000 /* don't assign controlling terminal */
#ifdef KERNEL
/* convert from open() flags to/from fflags; convert O_RD/WR to FREAD/FWRITE */
#define FFLAGS(oflags) ((oflags) + 1)
#define OFLAGS(fflags) ((fflags) - 1)
/* bits to save after open */
#define FMASK (FREAD|FWRITE|FAPPEND|FASYNC|FFSYNC|FNONBLOCK)
/* bits settable by fcntl(F_SETFL, ...) */
#define FCNTLFLAGS (FAPPEND|FASYNC|FFSYNC|FNONBLOCK)
#endif
/*
* The O_* flags used to have only F* names, which were used in the kernel
* and by fcntl. We retain the F* names for the kernel f_flags field
* and for backward compatibility for fcntl.
*/
#ifndef _POSIX_SOURCE
#define FAPPEND O_APPEND /* kernel/compat */
#define FASYNC O_ASYNC /* kernel/compat */
#define FFSYNC O_FSYNC /* kernel */
#define FNONBLOCK O_NONBLOCK /* kernel */
#define FNDELAY O_NONBLOCK /* compat */
#define O_NDELAY O_NONBLOCK /* compat */
#endif
/*
* Constants used for fcntl(2)
*/
/* command values */
#define F_DUPFD 0 /* duplicate file descriptor */
#define F_GETFD 1 /* get file descriptor flags */
#define F_SETFD 2 /* set file descriptor flags */
#define F_GETFL 3 /* get file status flags */
#define F_SETFL 4 /* set file status flags */
#ifndef _POSIX_SOURCE
#define F_GETOWN 5 /* get SIGIO/SIGURG proc/pgrp */
#define F_SETOWN 6 /* set SIGIO/SIGURG proc/pgrp */
#endif
#define F_GETLK 7 /* get record locking information */
#define F_SETLK 8 /* set record locking information */
#define F_SETLKW 9 /* F_SETLK; wait if blocked */
/* file descriptor flags (F_GETFD, F_SETFD) */
#define FD_CLOEXEC 1 /* close-on-exec flag */
/* record locking flags (F_GETLK, F_SETLK, F_SETLKW) */
#define F_RDLCK 1 /* shared or read lock */
#define F_UNLCK 2 /* unlock */
#define F_WRLCK 3 /* exclusive or write lock */
#ifdef KERNEL
#define F_WAIT 0x010 /* Wait until lock is granted */
#define F_FLOCK 0x020 /* Use flock(2) semantics for lock */
#define F_POSIX 0x040 /* Use POSIX semantics for lock */
#endif
/*
* Advisory file segment locking data type -
* information passed to system by user
*/
struct flock {
off_t l_start; /* starting offset */
off_t l_len; /* len = 0 means until end of file */
pid_t l_pid; /* lock owner */
short l_type; /* lock type: read/write, etc. */
short l_whence; /* type of l_start */
};
#ifndef _POSIX_SOURCE
/* lock operations for flock(2) */
#define LOCK_SH 0x01 /* shared file lock */
#define LOCK_EX 0x02 /* exclusive file lock */
#define LOCK_NB 0x04 /* don't block when locking */
#define LOCK_UN 0x08 /* unlock file */
#endif
#ifndef KERNEL
#include <sys/cdefs.h>
__BEGIN_DECLS
int open __P((const char *, int, ...));
int creat __P((const char *, mode_t));
int fcntl __P((int, int, ...));
#ifndef _POSIX_SOURCE
int flock __P((int, int));
#endif /* !_POSIX_SOURCE */
__END_DECLS
#endif
#endif /* !_SYS_FCNTL_H_ */