diff options
| -rw-r--r-- | lib/libthr/thread/thr_rwlock.c | 65 | ||||
| -rw-r--r-- | share/man/man3/Makefile | 2 | ||||
| -rw-r--r-- | share/man/man3/pthread_rwlock_timedrdlock.3 | 118 | ||||
| -rw-r--r-- | share/man/man3/pthread_rwlock_timedwrlock.3 | 107 |
4 files changed, 281 insertions, 11 deletions
diff --git a/lib/libthr/thread/thr_rwlock.c b/lib/libthr/thread/thr_rwlock.c index f819a80..afd2fa5 100644 --- a/lib/libthr/thread/thr_rwlock.c +++ b/lib/libthr/thread/thr_rwlock.c @@ -40,13 +40,17 @@ __weak_reference(_pthread_rwlock_destroy, pthread_rwlock_destroy); __weak_reference(_pthread_rwlock_init, pthread_rwlock_init); __weak_reference(_pthread_rwlock_rdlock, pthread_rwlock_rdlock); +__weak_reference(_pthread_rwlock_timedrdlock, pthread_rwlock_timedrdlock); +__weak_reference(_pthread_rwlock_timedwrlock, pthread_rwlock_timedwrlock); __weak_reference(_pthread_rwlock_tryrdlock, pthread_rwlock_tryrdlock); __weak_reference(_pthread_rwlock_trywrlock, pthread_rwlock_trywrlock); __weak_reference(_pthread_rwlock_unlock, pthread_rwlock_unlock); __weak_reference(_pthread_rwlock_wrlock, pthread_rwlock_wrlock); -static int rwlock_rdlock_common(pthread_rwlock_t *, int); -static int rwlock_wrlock_common(pthread_rwlock_t *, int); +static int rwlock_rdlock_common(pthread_rwlock_t *, int, + const struct timespec *); +static int rwlock_wrlock_common(pthread_rwlock_t *, int, + const struct timespec *); int _pthread_rwlock_destroy (pthread_rwlock_t *rwlock) @@ -116,7 +120,8 @@ out_mutex: * it is greater than 0 it will return immediately with EBUSY. */ static int -rwlock_rdlock_common(pthread_rwlock_t *rwlock, int nonblocking) +rwlock_rdlock_common(pthread_rwlock_t *rwlock, int nonblocking, + const struct timespec *timeout) { pthread_rwlock_t prwlock; int ret; @@ -124,6 +129,13 @@ rwlock_rdlock_common(pthread_rwlock_t *rwlock, int nonblocking) if (rwlock == NULL || *rwlock == NULL) return(EINVAL); + /* + * Check for validity of the timeout parameter. + */ + if (timeout != NULL && + (timeout->tv_nsec < 0 || timeout->tv_nsec >= 1000000000)) + return (EINVAL); + prwlock = *rwlock; /* grab the monitor lock */ @@ -143,7 +155,12 @@ rwlock_rdlock_common(pthread_rwlock_t *rwlock, int nonblocking) return (EBUSY); } - ret = pthread_cond_wait(&prwlock->read_signal, &prwlock->lock); + if (timeout == NULL) + ret = pthread_cond_wait(&prwlock->read_signal, + &prwlock->lock); + else + ret = pthread_cond_timedwait(&prwlock->read_signal, + &prwlock->lock, timeout); if (ret != 0 && ret != EINTR) { /* can't do a whole lot if this fails */ @@ -168,13 +185,20 @@ rwlock_rdlock_common(pthread_rwlock_t *rwlock, int nonblocking) int _pthread_rwlock_rdlock (pthread_rwlock_t *rwlock) { - return (rwlock_rdlock_common(rwlock, 0)); + return (rwlock_rdlock_common(rwlock, 0, NULL)); +} + +int +_pthread_rwlock_timedrdlock(pthread_rwlock_t *rwlock, + const struct timespec *timeout) +{ + return (rwlock_rdlock_common(rwlock, 0, timeout)); } int _pthread_rwlock_tryrdlock (pthread_rwlock_t *rwlock) { - return (rwlock_rdlock_common(rwlock, 1)); + return (rwlock_rdlock_common(rwlock, 1, NULL)); } int @@ -215,13 +239,20 @@ _pthread_rwlock_unlock (pthread_rwlock_t *rwlock) int _pthread_rwlock_wrlock (pthread_rwlock_t *rwlock) { - return (rwlock_wrlock_common(rwlock, 0)); + return (rwlock_wrlock_common(rwlock, 0, NULL)); +} + +int +_pthread_rwlock_timedwrlock (pthread_rwlock_t *rwlock, + const struct timespec *timeout) +{ + return (rwlock_wrlock_common(rwlock, 0, timeout)); } int _pthread_rwlock_trywrlock (pthread_rwlock_t *rwlock) { - return (rwlock_wrlock_common(rwlock, 1)); + return (rwlock_wrlock_common(rwlock, 1, NULL)); } /* @@ -229,7 +260,8 @@ _pthread_rwlock_trywrlock (pthread_rwlock_t *rwlock) * it is greater than 0 it will return immediately with EBUSY. */ static int -rwlock_wrlock_common(pthread_rwlock_t *rwlock, int nonblocking) +rwlock_wrlock_common(pthread_rwlock_t *rwlock, int nonblocking, + const struct timespec *timeout) { pthread_rwlock_t prwlock; int ret; @@ -237,6 +269,13 @@ rwlock_wrlock_common(pthread_rwlock_t *rwlock, int nonblocking) if (rwlock == NULL || *rwlock == NULL) return(EINVAL); + /* + * Check the timeout value for validity. + */ + if (timeout != NULL && + (timeout->tv_nsec < 0 || timeout->tv_nsec >= 1000000000)) + return (EINVAL); + prwlock = *rwlock; /* grab the monitor lock */ @@ -251,8 +290,12 @@ rwlock_wrlock_common(pthread_rwlock_t *rwlock, int nonblocking) ++prwlock->blocked_writers; - ret = pthread_cond_wait(&prwlock->write_signal, - &prwlock->lock); + if (timeout == NULL) + ret = pthread_cond_wait(&prwlock->write_signal, + &prwlock->lock); + else + ret = pthread_cond_timedwait(&prwlock->write_signal, + &prwlock->lock, timeout); if (ret != 0 && ret != EINTR) { --prwlock->blocked_writers; diff --git a/share/man/man3/Makefile b/share/man/man3/Makefile index 8af8e82..05120fe 100644 --- a/share/man/man3/Makefile +++ b/share/man/man3/Makefile @@ -155,6 +155,8 @@ MAN+= pthread.3 \ pthread_rwlock_destroy.3 \ pthread_rwlock_init.3 \ pthread_rwlock_rdlock.3 \ + pthread_rwlock_timedrdlock.3 \ + pthread_rwlock_timedwrlock.3 \ pthread_rwlock_unlock.3 \ pthread_rwlock_wrlock.3 \ pthread_rwlockattr_destroy.3 \ diff --git a/share/man/man3/pthread_rwlock_timedrdlock.3 b/share/man/man3/pthread_rwlock_timedrdlock.3 new file mode 100644 index 0000000..d08ea72 --- /dev/null +++ b/share/man/man3/pthread_rwlock_timedrdlock.3 @@ -0,0 +1,118 @@ +.\" Copyright (c) 2004 Michael Telahun Makonnen +.\" All rights reserved. +.\" +.\" 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. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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. +.\" +.\" $FreeBSD$ +.\" +.Dd January 16, 2004 +.Dt PTHREAD_RWLOCK_TIMEDRDLOCK 3 +.Os +.Sh NAME +.Nm pthread_rwlock_timedrdlock , +.Nd acquire a read-write lock for reading or give up after a specified period +.Sh LIBRARY +.Lb libpthread +.Lb libthr +.Sh SYNOPSIS +.In pthread.h +.Ft int +.Fn pthread_rwlock_timedrdlock "pthread_rwlock_t *rwlock" "const struct timespec *abs_timeout" +.Sh DESCRIPTION +This function acquires a read lock on the read-write lock +.Fa rwlock . +However, if the lock cannot be +acquired without waiting for another thread to +unlock the lock, +this wait shall be terminated when +.Fa abs_timeout +expires. +.Pp +.Pp +A thread may hold multiple concurrent read locks. +The +.Fn pthread_rwlock_unlock +function must be called once for each lock acquired. +.Pp +If the thread should be interrupted by a signal, +the +.Fn pthread_rwlock_wrlock +function will be automatically restarted after the thread returns from +the signal handler. +.Pp +The calling thread may deadlock if +at the time the call is made it holds a write lock on +.Fa rwlock . +The results are undefined if this function is called with +an uninitialized read-write lock. +.Sh IMPLEMENTATION NOTES +To prevent writer starvation, writers are favored over readers. +.Sh RETURN VALUES +If successful, the +.Fn pthread_rwlock_timedrdlock +function will return zero. Otherwise an error number will be returned +to indicate the error. +.Pp +This function shall not return an error code of EINTR. +.Sh ERRORS +The +.Fn pthread_rwlock_timedrdlock +function will fail if: +.Bl -tag -width Er +.It Bq Er ETIMEDOUT +The lock could not be acquired before the specified timeout expired +.El +.Pp +The +.Fn pthread_rwlock_timedrdlock +function may fail if: +.Bl -tag -width Er +.It Bq Er EAGAIN +The read lock could not be +acquired because the maximum number of read locks for +.Fa rwlock +would be exceeded. +.It Bq Er EDEADLK +The calling thread already holds a write lock on +.Fa rwlock . +.It Bq Er EINVAL +The value specified by +.Fa rwlock +does not refer to an initialized read-write lock object, +or the +.Fa abs_timeout nanosecond value is less than zero or +greater than or equal to 1 billion. +.El +.Sh SEE ALSO +.Xr pthread_rwlock_init 3 , +.Xr pthread_rwlock_timedwrlock 3 +.Xr pthread_rwlock_unlock 3 , +.Sh STANDARDS +The +.Fn pthread_rwlock_timedrdlock +function is expected to conform to +.St -p1003.1-96 . +.Sh HISTORY +The +.Fn pthread_rwlock_timedrdlock +function first appeared in +.Fx 5.2 . diff --git a/share/man/man3/pthread_rwlock_timedwrlock.3 b/share/man/man3/pthread_rwlock_timedwrlock.3 new file mode 100644 index 0000000..efe45dc --- /dev/null +++ b/share/man/man3/pthread_rwlock_timedwrlock.3 @@ -0,0 +1,107 @@ +.\" Copyright (c) 2004 Michael Telahun Makonnen +.\" All rights reserved. +.\" +.\" 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. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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. +.\" +.\" $FreeBSD$ +.\" +.Dd January 16, 2004 +.Dt PTHREAD_RWLOCK_TIMEDWRLOCK 3 +.Os +.Sh NAME +.Nm pthread_rwlock_timedwrlock , +.Nd acquire a read-write lock for writing or give up after a specified period +.Sh LIBRARY +.Lb libpthread +.Lb libthr +.Sh SYNOPSIS +.In pthread.h +.Ft int +.Fn pthread_rwlock_timedwrlock "pthread_rwlock_t *rwlock" "const struct timespec *abs_timeout" +.Sh DESCRIPTION +This function acquires a write lock on the read-write lock +.Fa rwlock . +However, if the lock cannot be +acquired without waiting for another thread to +unlock the lock, +this wait shall be terminated when +.Fa abs_timeout +expires. +.Pp +If the thread should be interrupted by a signal, +the +.Fn pthread_rwlock_wrlock +function will be automatically restarted after the thread returns from +the signal handler. +.Pp +The calling thread may deadlock if +at the time the call is made it holds +.Fa rwlock . +The results are undefined if this function is called with +an uninitialized read-write lock. +.Sh IMPLEMENTATION NOTES +To prevent writer starvation, writers are favored over readers. +.Sh RETURN VALUES +If successful, the +.Fn pthread_rwlock_timedwrlock +function will return zero. Otherwise an error number will be returned +to indicate the error. +.Pp +This function shall not return an error code of EINTR. +.Sh ERRORS +The +.Fn pthread_rwlock_timedwrlock +function shall fail if: +.Bl -tag -width Er +.It Bq Er ETIMEDOUT +The lock could not be acquired before the specified timeout expired +.El +.Pp +The +.Fn pthread_rwlock_timedrwlock +function may fail if: +.Bl -tag -width Er +.It Bq Er EDEADLK +The calling thread already holds +.Fa rwlock . +.It Bq Er EINVAL +The value specified by +.Fa rwlock +does not refer to an initialized read-write lock object, +or the +.Fa abs_timeout nanosecond value is less than zero or +greater than or equal to 1 billion. +.El +.Sh SEE ALSO +.Xr pthread_rwlock_init 3 , +.Xr pthread_rwlock_timedrdlock 3 +.Xr pthread_rwlock_unlock 3 , +.Sh STANDARDS +The +.Fn pthread_rwlock_timedwrlock +function is expected to conform to +.St -p1003.1-96 . +.Sh HISTORY +The +.Fn pthread_rwlock_timedwrlock +function first appeared in +.Fx 5.2 . |
