b9de27c005
a knob to force process scope threads. If the environment variable
LIBPTHREAD_PROCESS_SCOPE is set, force all threads to be process
scope threads regardless of how the application creates them. If
LIBPTHREAD_SYSTEM_SCOPE is set (forcing system scope threads), it
overrides LIBPTHREAD_PROCESS_SCOPE.
$ # To force system scope threads
$ LIBPTHREAD_SYSTEM_SCOPE=anything threaded_app
$ # To force process scope threads
$ LIBPTHREAD_PROCESS_SCOPE=anything threaded_app
347 lines
11 KiB
C
347 lines
11 KiB
C
/*
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* Copyright (c) 2003 Daniel M. Eischen <deischen@gdeb.com>
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* Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
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* All rights reserved.
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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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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by John Birrell.
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* 4. Neither the name of the author nor the names of any co-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 JOHN BIRRELL 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 AUTHOR 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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* $FreeBSD$
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*/
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#include <errno.h>
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#include <stdlib.h>
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#include <string.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <stddef.h>
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#include <sys/time.h>
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#include <machine/reg.h>
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#include <pthread.h>
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#include "thr_private.h"
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#include "libc_private.h"
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static void free_thread(struct pthread *curthread, struct pthread *thread);
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static int create_stack(struct pthread_attr *pattr);
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static void free_stack(struct pthread_attr *pattr);
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static void thread_start(struct pthread *curthread,
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void *(*start_routine) (void *), void *arg);
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__weak_reference(_pthread_create, pthread_create);
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/*
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* Some notes on new thread creation and first time initializion
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* to enable multi-threading.
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*
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* There are basically two things that need to be done.
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*
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* 1) The internal library variables must be initialized.
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* 2) Upcalls need to be enabled to allow multiple threads
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* to be run.
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*
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* The first may be done as a result of other pthread functions
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* being called. When _thr_initial is null, _libpthread_init is
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* called to initialize the internal variables; this also creates
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* or sets the initial thread. It'd be nice to automatically
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* have _libpthread_init called on program execution so we don't
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* have to have checks throughout the library.
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*
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* The second part is only triggered by the creation of the first
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* thread (other than the initial/main thread). If the thread
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* being created is a scope system thread, then a new KSE/KSEG
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* pair needs to be allocated. Also, if upcalls haven't been
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* enabled on the initial thread's KSE, they must be now that
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* there is more than one thread; this could be delayed until
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* the initial KSEG has more than one thread.
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*/
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int
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_pthread_create(pthread_t * thread, const pthread_attr_t * attr,
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void *(*start_routine) (void *), void *arg)
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{
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struct pthread *curthread, *new_thread;
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struct kse *kse = NULL;
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struct kse_group *kseg = NULL;
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kse_critical_t crit;
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int ret = 0;
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if (_thr_initial == NULL)
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_libpthread_init(NULL);
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/*
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* Turn on threaded mode, if failed, it is unnecessary to
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* do further work.
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*/
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if (_kse_isthreaded() == 0 && _kse_setthreaded(1)) {
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return (EAGAIN);
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}
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curthread = _get_curthread();
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/*
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* Allocate memory for the thread structure.
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* Some functions use malloc, so don't put it
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* in a critical region.
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*/
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if ((new_thread = _thr_alloc(curthread)) == NULL) {
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/* Insufficient memory to create a thread: */
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ret = EAGAIN;
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} else {
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/* Check if default thread attributes are required: */
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if (attr == NULL || *attr == NULL)
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/* Use the default thread attributes: */
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new_thread->attr = _pthread_attr_default;
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else {
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new_thread->attr = *(*attr);
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if ((*attr)->sched_inherit == PTHREAD_INHERIT_SCHED) {
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/* inherit scheduling contention scop */
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if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM)
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new_thread->attr.flags |= PTHREAD_SCOPE_SYSTEM;
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else
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new_thread->attr.flags &= ~PTHREAD_SCOPE_SYSTEM;
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/*
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* scheduling policy and scheduling parameters will be
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* inherited in following code.
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*/
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}
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}
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if (_thread_scope_system > 0)
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new_thread->attr.flags |= PTHREAD_SCOPE_SYSTEM;
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else if ((_thread_scope_system < 0)
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&& (thread != &_thr_sig_daemon))
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new_thread->attr.flags &= ~PTHREAD_SCOPE_SYSTEM;
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if (create_stack(&new_thread->attr) != 0) {
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/* Insufficient memory to create a stack: */
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ret = EAGAIN;
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_thr_free(curthread, new_thread);
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}
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else if (((new_thread->attr.flags & PTHREAD_SCOPE_SYSTEM) != 0) &&
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(((kse = _kse_alloc(curthread, 1)) == NULL)
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|| ((kseg = _kseg_alloc(curthread)) == NULL))) {
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/* Insufficient memory to create a new KSE/KSEG: */
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ret = EAGAIN;
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if (kse != NULL) {
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kse->k_kcb->kcb_kmbx.km_flags |= KMF_DONE;
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_kse_free(curthread, kse);
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}
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free_stack(&new_thread->attr);
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_thr_free(curthread, new_thread);
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}
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else {
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if (kseg != NULL) {
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/* Add the KSE to the KSEG's list of KSEs. */
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TAILQ_INSERT_HEAD(&kseg->kg_kseq, kse, k_kgqe);
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kseg->kg_ksecount = 1;
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kse->k_kseg = kseg;
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kse->k_schedq = &kseg->kg_schedq;
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}
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/*
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* Write a magic value to the thread structure
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* to help identify valid ones:
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*/
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new_thread->magic = THR_MAGIC;
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new_thread->slice_usec = -1;
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new_thread->start_routine = start_routine;
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new_thread->arg = arg;
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new_thread->cancelflags = PTHREAD_CANCEL_ENABLE |
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PTHREAD_CANCEL_DEFERRED;
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/* No thread is wanting to join to this one: */
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new_thread->joiner = NULL;
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/* Initialize the signal frame: */
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new_thread->curframe = NULL;
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/*
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* Initialize the machine context.
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* Enter a critical region to get consistent context.
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*/
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crit = _kse_critical_enter();
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THR_GETCONTEXT(&new_thread->tcb->tcb_tmbx.tm_context);
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/* Initialize the thread for signals: */
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new_thread->sigmask = curthread->sigmask;
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_kse_critical_leave(crit);
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new_thread->tcb->tcb_tmbx.tm_udata = new_thread;
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new_thread->tcb->tcb_tmbx.tm_context.uc_sigmask =
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new_thread->sigmask;
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new_thread->tcb->tcb_tmbx.tm_context.uc_stack.ss_size =
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new_thread->attr.stacksize_attr;
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new_thread->tcb->tcb_tmbx.tm_context.uc_stack.ss_sp =
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new_thread->attr.stackaddr_attr;
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makecontext(&new_thread->tcb->tcb_tmbx.tm_context,
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(void (*)(void))thread_start, 3, new_thread,
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start_routine, arg);
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/*
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* Check if this thread is to inherit the scheduling
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* attributes from its parent:
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*/
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if (new_thread->attr.sched_inherit == PTHREAD_INHERIT_SCHED) {
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/*
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* Copy the scheduling attributes.
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* Lock the scheduling lock to get consistent
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* scheduling parameters.
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*/
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THR_SCHED_LOCK(curthread, curthread);
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new_thread->base_priority =
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curthread->base_priority &
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~THR_SIGNAL_PRIORITY;
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new_thread->attr.prio =
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curthread->base_priority &
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~THR_SIGNAL_PRIORITY;
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new_thread->attr.sched_policy =
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curthread->attr.sched_policy;
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THR_SCHED_UNLOCK(curthread, curthread);
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} else {
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/*
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* Use just the thread priority, leaving the
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* other scheduling attributes as their
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* default values:
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*/
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new_thread->base_priority =
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new_thread->attr.prio;
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}
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new_thread->active_priority = new_thread->base_priority;
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new_thread->inherited_priority = 0;
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/* Initialize the mutex queue: */
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TAILQ_INIT(&new_thread->mutexq);
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/* Initialise hooks in the thread structure: */
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new_thread->specific = NULL;
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new_thread->specific_data_count = 0;
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new_thread->cleanup = NULL;
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new_thread->flags = 0;
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new_thread->continuation = NULL;
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new_thread->wakeup_time.tv_sec = -1;
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new_thread->lock_switch = 0;
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sigemptyset(&new_thread->sigpend);
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new_thread->check_pending = 0;
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new_thread->locklevel = 0;
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new_thread->rdlock_count = 0;
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new_thread->sigstk.ss_sp = 0;
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new_thread->sigstk.ss_size = 0;
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new_thread->sigstk.ss_flags = SS_DISABLE;
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new_thread->oldsigmask = NULL;
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if (new_thread->attr.suspend == THR_CREATE_SUSPENDED) {
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new_thread->state = PS_SUSPENDED;
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new_thread->flags = THR_FLAGS_SUSPENDED;
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}
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else
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new_thread->state = PS_RUNNING;
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/*
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* System scope threads have their own kse and
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* kseg. Process scope threads are all hung
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* off the main process kseg.
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*/
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if ((new_thread->attr.flags & PTHREAD_SCOPE_SYSTEM) == 0) {
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new_thread->kseg = _kse_initial->k_kseg;
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new_thread->kse = _kse_initial;
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}
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else {
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kse->k_curthread = NULL;
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kse->k_kseg->kg_flags |= KGF_SINGLE_THREAD;
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new_thread->kse = kse;
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new_thread->kseg = kse->k_kseg;
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kse->k_kcb->kcb_kmbx.km_udata = kse;
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kse->k_kcb->kcb_kmbx.km_curthread = NULL;
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}
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/*
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* Schedule the new thread starting a new KSEG/KSE
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* pair if necessary.
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*/
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ret = _thr_schedule_add(curthread, new_thread);
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if (ret != 0)
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free_thread(curthread, new_thread);
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else {
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/* Return a pointer to the thread structure: */
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(*thread) = new_thread;
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}
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}
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}
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/* Return the status: */
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return (ret);
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}
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static void
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free_thread(struct pthread *curthread, struct pthread *thread)
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{
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free_stack(&thread->attr);
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if ((thread->attr.flags & PTHREAD_SCOPE_SYSTEM) != 0) {
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/* Free the KSE and KSEG. */
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_kseg_free(thread->kseg);
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_kse_free(curthread, thread->kse);
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}
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_thr_free(curthread, thread);
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}
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static int
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create_stack(struct pthread_attr *pattr)
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{
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int ret;
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/* Check if a stack was specified in the thread attributes: */
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if ((pattr->stackaddr_attr) != NULL) {
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pattr->guardsize_attr = 0;
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pattr->flags |= THR_STACK_USER;
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ret = 0;
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}
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else
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ret = _thr_stack_alloc(pattr);
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return (ret);
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}
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static void
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free_stack(struct pthread_attr *pattr)
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{
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struct kse *curkse;
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kse_critical_t crit;
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if ((pattr->flags & THR_STACK_USER) == 0) {
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crit = _kse_critical_enter();
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curkse = _get_curkse();
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KSE_LOCK_ACQUIRE(curkse, &_thread_list_lock);
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/* Stack routines don't use malloc/free. */
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_thr_stack_free(pattr);
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KSE_LOCK_RELEASE(curkse, &_thread_list_lock);
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_kse_critical_leave(crit);
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}
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}
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static void
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thread_start(struct pthread *curthread, void *(*start_routine) (void *),
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void *arg)
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{
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/* Run the current thread's start routine with argument: */
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pthread_exit(start_routine(arg));
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/* This point should never be reached. */
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PANIC("Thread has resumed after exit");
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}
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