dc5114efb5
a lock is being waitied on. Fix a races in join and cancellation. When trying to wait on a CV and the library is not yet threaded, make it threaded so that waiting actually works. When trying to nanosleep() and we're not threaded, just call the system call nanosleep instead of adding the thread to the wait queue. Clean up adding/removing new threads to the "all threads queue", assigning them unique ids, and tracking how many active threads there are. Do it all when the thread is added to the scheduling queue instead of making pthread_create() know how to do it. Fix a race where a thread could be marked for signal delivery but it could be exited before we actually add the signal to it. Other minor cleanups and bug fixes. Submitted by: davidxu Approved by: re@ (blanket for libpthread)
348 lines
11 KiB
C
348 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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#define OFF(f) offsetof(struct pthread, f)
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int _thread_next_offset = OFF(tle.tqe_next);
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int _thread_uniqueid_offset = OFF(uniqueid);
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int _thread_state_offset = OFF(state);
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int _thread_name_offset = OFF(name);
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int _thread_ctx_offset = OFF(tmbx.tm_context);
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#undef OFF
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int _thread_PS_RUNNING_value = PS_RUNNING;
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int _thread_PS_DEAD_value = PS_DEAD;
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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 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 kse *curkse;
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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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void *p;
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kse_critical_t crit;
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int i;
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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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/* Initialize the thread structure: */
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p = new_thread->alloc_addr;
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memset(new_thread, 0, sizeof(struct pthread));
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new_thread->alloc_addr = p;
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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 (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)) == 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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#ifndef KMF_DONE
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#define KMF_DONE 0x04
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#endif
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if (kse != NULL) {
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kse->k_mbx.km_flags |= KMF_DONE;
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_kse_free(curthread, kse);
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}
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if ((new_thread->attr.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(&new_thread->attr);
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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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_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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/* Initialize the thread for signals: */
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new_thread->sigmask = curthread->sigmask;
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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->tmbx.tm_context);
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_kse_critical_leave(crit);
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new_thread->tmbx.tm_udata = new_thread;
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new_thread->tmbx.tm_context.uc_sigmask =
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new_thread->sigmask;
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new_thread->tmbx.tm_context.uc_stack.ss_size =
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new_thread->attr.stacksize_attr;
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new_thread->tmbx.tm_context.uc_stack.ss_sp =
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new_thread->attr.stackaddr_attr;
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makecontext(&new_thread->tmbx.tm_context,
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(void (*)(void))thread_start, 4, 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.flags & PTHREAD_INHERIT_SCHED) != 0) {
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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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/*
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* Initialize thread locking.
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* Lock initializing needs malloc, so don't
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* enter critical region before doing this!
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*/
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if (_lock_init(&new_thread->lock, LCK_ADAPTIVE,
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_thr_lock_wait, _thr_lock_wakeup) != 0)
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PANIC("Cannot initialize thread lock");
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for (i = 0; i < MAX_THR_LOCKLEVEL; i++) {
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_lockuser_init(&new_thread->lockusers[i],
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(void *)new_thread);
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_LCK_SET_PRIVATE2(&new_thread->lockusers[i],
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(void *)new_thread);
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}
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/* Initialise hooks in the thread structure: */
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new_thread->specific = NULL;
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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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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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#ifdef NOT_YET
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kse->k_kseg->kg_flags |= KGF_SINGLE_THREAD;
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#endif
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new_thread->kse = kse;
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new_thread->kseg = kse->k_kseg;
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kse->k_mbx.km_udata = kse;
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kse->k_mbx.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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/* 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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/* 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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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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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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