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freebsd-dev/lib/libc_r/uthread/uthread_wait4.c

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Reviewed by: julian Submitted by: john birrel One version of the pthreads library another will follow with differnt actions under some cases.. not QUITE complete
1996-01-22 00:23:58 +00:00
/*
Change signal model to match POSIX (i.e. one set of signal handlers for the process, not a separate set for each thread). By default, the process now only has signal handlers installed for SIGVTALRM, SIGINFO and SIGCHLD. The thread kernel signal handler is installed for other signals on demand. This means that SIG_IGN and SIG_DFL processing is now left to the kernel, not the thread kernel. Change the signal dispatch to no longer use a signal thread, and call the signal handler using the stack of the thread that has the signal pending. Change the atomic lock method to use test-and-set asm code with a yield if blocked. This introduces separate locks for each type of object instead of blocking signals to prevent a context switch. It was this blocking of signals that caused the performance degradation the people have noted. This is a *big* change!
1998-04-29 09:59:34 +00:00
* Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
Reviewed by: julian Submitted by: john birrel One version of the pthreads library another will follow with differnt actions under some cases.. not QUITE complete
1996-01-22 00:23:58 +00:00
* 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by John Birrell.
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL 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
Add RCS IDs to those files without them. Fix copyrights (s/REGENTS/AUTHOR). Suggested by: tg Approved by: jb
1999-08-05 12:15:30 +00:00
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
Reviewed by: julian Submitted by: john birrel One version of the pthreads library another will follow with differnt actions under some cases.. not QUITE complete
1996-01-22 00:23:58 +00:00
* 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.
*
$Id$ -> $FreeBSD$
1999-08-28 00:22:10 +00:00
* $FreeBSD$
Reviewed by: julian Submitted by: john birrel One version of the pthreads library another will follow with differnt actions under some cases.. not QUITE complete
1996-01-22 00:23:58 +00:00
*/
#include <errno.h>
#include <sys/wait.h>
#ifdef _THREAD_SAFE
#include <pthread.h>
#include "pthread_private.h"
pid_t
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
_wait4(pid_t pid, int *istat, int options, struct rusage * rusage)
Reviewed by: julian Submitted by: john birrel One version of the pthreads library another will follow with differnt actions under some cases.. not QUITE complete
1996-01-22 00:23:58 +00:00
{
Fixes for signal handling: o Don't call signal handlers with the signal handler access lock held. o Remove pending signals before calling signal handlers. If pending signals were not removed prior to handling them, invocation of the handler could cause the handler to be called more than once for the same signal. Found by: JB o When SIGCHLD arrives, wake up all threads in PS_WAIT_WAIT (wait4). PR: bin/15328 Reviewed by: jasone
1999-12-17 00:56:36 +00:00
pid_t ret;
Reviewed by: julian Submitted by: john birrel One version of the pthreads library another will follow with differnt actions under some cases.. not QUITE complete
1996-01-22 00:23:58 +00:00
Defer signals, so we will not wait for SIGCHLD after it was delivered.
1999-06-29 19:57:07 +00:00
_thread_kern_sig_defer();
Reviewed by: julian Submitted by: john birrel One version of the pthreads library another will follow with differnt actions under some cases.. not QUITE complete
1996-01-22 00:23:58 +00:00
/* Perform a non-blocking wait4 syscall: */
while ((ret = _thread_sys_wait4(pid, istat, options | WNOHANG, rusage)) == 0 && (options & WNOHANG) == 0) {
Change signal model to match POSIX (i.e. one set of signal handlers for the process, not a separate set for each thread). By default, the process now only has signal handlers installed for SIGVTALRM, SIGINFO and SIGCHLD. The thread kernel signal handler is installed for other signals on demand. This means that SIG_IGN and SIG_DFL processing is now left to the kernel, not the thread kernel. Change the signal dispatch to no longer use a signal thread, and call the signal handler using the stack of the thread that has the signal pending. Change the atomic lock method to use test-and-set asm code with a yield if blocked. This introduces separate locks for each type of object instead of blocking signals to prevent a context switch. It was this blocking of signals that caused the performance degradation the people have noted. This is a *big* change!
1998-04-29 09:59:34 +00:00
/* Reset the interrupted operation flag: */
_thread_run->interrupted = 0;
Reviewed by: julian Submitted by: john birrel One version of the pthreads library another will follow with differnt actions under some cases.. not QUITE complete
1996-01-22 00:23:58 +00:00
/* Schedule the next thread while this one waits: */
_thread_kern_sched_state(PS_WAIT_WAIT, __FILE__, __LINE__);
/* Check if this call was interrupted by a signal: */
Change signal model to match POSIX (i.e. one set of signal handlers for the process, not a separate set for each thread). By default, the process now only has signal handlers installed for SIGVTALRM, SIGINFO and SIGCHLD. The thread kernel signal handler is installed for other signals on demand. This means that SIG_IGN and SIG_DFL processing is now left to the kernel, not the thread kernel. Change the signal dispatch to no longer use a signal thread, and call the signal handler using the stack of the thread that has the signal pending. Change the atomic lock method to use test-and-set asm code with a yield if blocked. This introduces separate locks for each type of object instead of blocking signals to prevent a context switch. It was this blocking of signals that caused the performance degradation the people have noted. This is a *big* change!
1998-04-29 09:59:34 +00:00
if (_thread_run->interrupted) {
errno = EINTR;
Reviewed by: julian Submitted by: john birrel One version of the pthreads library another will follow with differnt actions under some cases.. not QUITE complete
1996-01-22 00:23:58 +00:00
ret = -1;
break;
}
}
Defer signals, so we will not wait for SIGCHLD after it was delivered.
1999-06-29 19:57:07 +00:00
_thread_kern_sig_undefer();
Reviewed by: julian Submitted by: john birrel One version of the pthreads library another will follow with differnt actions under some cases.. not QUITE complete
1996-01-22 00:23:58 +00:00
return (ret);
}
Track libc's three-tier symbol naming. libc_r must currently implement the _libc_*() entry points and add *() weak aliases. This will all change for the better when libc_r becomes libpthread.
2000-01-12 09:28:58 +00:00
Use __strong_reference() instead of __weak_reference() to assure that the weak symbols of the same name are not used.
2000-01-29 22:53:55 +00:00
__strong_reference(_wait4, wait4);
Reviewed by: julian Submitted by: john birrel One version of the pthreads library another will follow with differnt actions under some cases.. not QUITE complete
1996-01-22 00:23:58 +00:00
#endif
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