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freebsd-dev/lib/libc/gen/lockf.c

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An implementation of lockf() function call. Obtained from: NetBSD (author: Klaus Klein)
1998-07-08 15:28:56 +00:00
/*-
* Copyright (c) 1997 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Klaus Klein.
*
* 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 NetBSD
* Foundation, Inc. and its contributors.
* 4. Neither the name of The NetBSD Foundation 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/
Fix SCM ID's.
2002-02-01 00:57:29 +00:00
/* $NetBSD: lockf.c,v 1.1 1997/12/20 20:23:18 kleink Exp $ */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
An implementation of lockf() function call. Obtained from: NetBSD (author: Klaus Klein)
1998-07-08 15:28:56 +00:00
Remove _THREAD_SAFE and make libc thread-safe by default by adding (weak definitions to) stubs for some of the pthread functions. If the threads library is linked in, the real pthread functions will pulled in. Use the following convention for system calls wrapped by the threads library: __sys_foo - actual system call _foo - weak definition to __sys_foo foo - weak definition to __sys_foo Change all libc uses of system calls wrapped by the threads library from foo to _foo. In order to define the prototypes for _foo(), we introduce namespace.h and un-namespace.h (suggested by bde). All files that need to reference these system calls, should include namespace.h before any standard includes, then include un-namespace.h after the standard includes and before any local includes. <db.h> is an exception and shouldn't be included in between namespace.h and un-namespace.h namespace.h will define foo to _foo, and un-namespace.h will undefine foo. Try to eliminate some of the recursive calls to MT-safe functions in libc/stdio in preparation for adding a mutex to FILE. We have recursive mutexes, but would like to avoid using them if possible. Remove uneeded includes of <errno.h> from a few files. Add $FreeBSD$ to a few files in order to pass commitprep. Approved by: -arch
2001-01-24 13:01:12 +00:00
#include "namespace.h"
An implementation of lockf() function call. Obtained from: NetBSD (author: Klaus Klein)
1998-07-08 15:28:56 +00:00
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
Remove _THREAD_SAFE and make libc thread-safe by default by adding (weak definitions to) stubs for some of the pthread functions. If the threads library is linked in, the real pthread functions will pulled in. Use the following convention for system calls wrapped by the threads library: __sys_foo - actual system call _foo - weak definition to __sys_foo foo - weak definition to __sys_foo Change all libc uses of system calls wrapped by the threads library from foo to _foo. In order to define the prototypes for _foo(), we introduce namespace.h and un-namespace.h (suggested by bde). All files that need to reference these system calls, should include namespace.h before any standard includes, then include un-namespace.h after the standard includes and before any local includes. <db.h> is an exception and shouldn't be included in between namespace.h and un-namespace.h namespace.h will define foo to _foo, and un-namespace.h will undefine foo. Try to eliminate some of the recursive calls to MT-safe functions in libc/stdio in preparation for adding a mutex to FILE. We have recursive mutexes, but would like to avoid using them if possible. Remove uneeded includes of <errno.h> from a few files. Add $FreeBSD$ to a few files in order to pass commitprep. Approved by: -arch
2001-01-24 13:01:12 +00:00
#include "un-namespace.h"
An implementation of lockf() function call. Obtained from: NetBSD (author: Klaus Klein)
1998-07-08 15:28:56 +00:00
int
lockf(filedes, function, size)
int filedes;
int function;
off_t size;
{
struct flock fl;
int cmd;
fl.l_start = 0;
fl.l_len = size;
fl.l_whence = SEEK_CUR;
switch (function) {
case F_ULOCK:
cmd = F_SETLK;
fl.l_type = F_UNLCK;
break;
case F_LOCK:
cmd = F_SETLKW;
fl.l_type = F_WRLCK;
break;
case F_TLOCK:
cmd = F_SETLK;
fl.l_type = F_WRLCK;
break;
case F_TEST:
fl.l_type = F_WRLCK;
Simplify sytem call renaming. Instead of _foo() <-- _libc_foo <-- foo(), just use _foo() <-- foo(). In the case of a libpthread that doesn't do call conversion (such as linuxthreads and our upcoming libpthread), this is adequate. In the case of libc_r, we still need three names, which are now _thread_sys_foo() <-- _foo() <-- foo(). Convert all internal libc usage of: aio_suspend(), close(), fsync(), msync(), nanosleep(), open(), fcntl(), read(), and write() to _foo() instead of foo(). Remove all internal libc usage of: creat(), pause(), sleep(), system(), tcdrain(), wait(), and waitpid(). Make thread cancellation fully POSIX-compliant. Suggested by: deischen
2000-01-27 23:07:25 +00:00
if (_fcntl(filedes, F_GETLK, &fl) == -1)
An implementation of lockf() function call. Obtained from: NetBSD (author: Klaus Klein)
1998-07-08 15:28:56 +00:00
return (-1);
Add the new kernel-mode NFS Lock Manager. To use it instead of the user-mode lock manager, build a kernel with the NFSLOCKD option and add '-k' to 'rpc_lockd_flags' in rc.conf. Highlights include: * Thread-safe kernel RPC client - many threads can use the same RPC client handle safely with replies being de-multiplexed at the socket upcall (typically driven directly by the NIC interrupt) and handed off to whichever thread matches the reply. For UDP sockets, many RPC clients can share the same socket. This allows the use of a single privileged UDP port number to talk to an arbitrary number of remote hosts. * Single-threaded kernel RPC server. Adding support for multi-threaded server would be relatively straightforward and would follow approximately the Solaris KPI. A single thread should be sufficient for the NLM since it should rarely block in normal operation. * Kernel mode NLM server supporting cancel requests and granted callbacks. I've tested the NLM server reasonably extensively - it passes both my own tests and the NFS Connectathon locking tests running on Solaris, Mac OS X and Ubuntu Linux. * Userland NLM client supported. While the NLM server doesn't have support for the local NFS client's locking needs, it does have to field async replies and granted callbacks from remote NLMs that the local client has contacted. We relay these replies to the userland rpc.lockd over a local domain RPC socket. * Robust deadlock detection for the local lock manager. In particular it will detect deadlocks caused by a lock request that covers more than one blocking request. As required by the NLM protocol, all deadlock detection happens synchronously - a user is guaranteed that if a lock request isn't rejected immediately, the lock will eventually be granted. The old system allowed for a 'deferred deadlock' condition where a blocked lock request could wake up and find that some other deadlock-causing lock owner had beaten them to the lock. * Since both local and remote locks are managed by the same kernel locking code, local and remote processes can safely use file locks for mutual exclusion. Local processes have no fairness advantage compared to remote processes when contending to lock a region that has just been unlocked - the local lock manager enforces a strict first-come first-served model for both local and remote lockers. Sponsored by: Isilon Systems PR: 95247 107555 115524 116679 MFC after: 2 weeks
2008-03-26 15:23:12 +00:00
if (fl.l_type == F_UNLCK || (fl.l_sysid == 0 && fl.l_pid == getpid()))
An implementation of lockf() function call. Obtained from: NetBSD (author: Klaus Klein)
1998-07-08 15:28:56 +00:00
return (0);
errno = EAGAIN;
return (-1);
/* NOTREACHED */
default:
errno = EINVAL;
return (-1);
/* NOTREACHED */
}
Simplify sytem call renaming. Instead of _foo() <-- _libc_foo <-- foo(), just use _foo() <-- foo(). In the case of a libpthread that doesn't do call conversion (such as linuxthreads and our upcoming libpthread), this is adequate. In the case of libc_r, we still need three names, which are now _thread_sys_foo() <-- _foo() <-- foo(). Convert all internal libc usage of: aio_suspend(), close(), fsync(), msync(), nanosleep(), open(), fcntl(), read(), and write() to _foo() instead of foo(). Remove all internal libc usage of: creat(), pause(), sleep(), system(), tcdrain(), wait(), and waitpid(). Make thread cancellation fully POSIX-compliant. Suggested by: deischen
2000-01-27 23:07:25 +00:00
return (_fcntl(filedes, cmd, &fl));
An implementation of lockf() function call. Obtained from: NetBSD (author: Klaus Klein)
1998-07-08 15:28:56 +00:00
}
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