FreeBSD-5.3/lib/libpthread/thread/thr_create.c
/*
* Copyright (c) 2003 Daniel M. Eischen <deischen@gdeb.com>
* Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
* 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
* 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: src/lib/libpthread/thread/thr_create.c,v 1.57 2004/08/12 12:12:12 deischen Exp $
*/
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <stddef.h>
#include <sys/time.h>
#include <machine/reg.h>
#include <pthread.h>
#include "thr_private.h"
#include "libc_private.h"
static void free_thread(struct pthread *curthread, struct pthread *thread);
static int create_stack(struct pthread_attr *pattr);
static void free_stack(struct pthread_attr *pattr);
static void thread_start(struct pthread *curthread,
void *(*start_routine) (void *), void *arg);
__weak_reference(_pthread_create, pthread_create);
/*
* Some notes on new thread creation and first time initializion
* to enable multi-threading.
*
* There are basically two things that need to be done.
*
* 1) The internal library variables must be initialized.
* 2) Upcalls need to be enabled to allow multiple threads
* to be run.
*
* The first may be done as a result of other pthread functions
* being called. When _thr_initial is null, _libpthread_init is
* called to initialize the internal variables; this also creates
* or sets the initial thread. It'd be nice to automatically
* have _libpthread_init called on program execution so we don't
* have to have checks throughout the library.
*
* The second part is only triggered by the creation of the first
* thread (other than the initial/main thread). If the thread
* being created is a scope system thread, then a new KSE/KSEG
* pair needs to be allocated. Also, if upcalls haven't been
* enabled on the initial thread's KSE, they must be now that
* there is more than one thread; this could be delayed until
* the initial KSEG has more than one thread.
*/
int
_pthread_create(pthread_t * thread, const pthread_attr_t * attr,
void *(*start_routine) (void *), void *arg)
{
struct pthread *curthread, *new_thread;
struct kse *kse = NULL;
struct kse_group *kseg = NULL;
kse_critical_t crit;
int ret = 0;
if (_thr_initial == NULL)
_libpthread_init(NULL);
/*
* Turn on threaded mode, if failed, it is unnecessary to
* do further work.
*/
if (_kse_isthreaded() == 0 && _kse_setthreaded(1)) {
return (EAGAIN);
}
curthread = _get_curthread();
/*
* Allocate memory for the thread structure.
* Some functions use malloc, so don't put it
* in a critical region.
*/
if ((new_thread = _thr_alloc(curthread)) == NULL) {
/* Insufficient memory to create a thread: */
ret = EAGAIN;
} else {
/* Check if default thread attributes are required: */
if (attr == NULL || *attr == NULL)
/* Use the default thread attributes: */
new_thread->attr = _pthread_attr_default;
else {
new_thread->attr = *(*attr);
if ((*attr)->sched_inherit == PTHREAD_INHERIT_SCHED) {
/* inherit scheduling contention scop */
if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM)
new_thread->attr.flags |= PTHREAD_SCOPE_SYSTEM;
else
new_thread->attr.flags &= ~PTHREAD_SCOPE_SYSTEM;
/*
* scheduling policy and scheduling parameters will be
* inherited in following code.
*/
}
}
if (_thread_scope_system > 0)
new_thread->attr.flags |= PTHREAD_SCOPE_SYSTEM;
else if ((_thread_scope_system < 0)
&& (thread != &_thr_sig_daemon))
new_thread->attr.flags &= ~PTHREAD_SCOPE_SYSTEM;
if (create_stack(&new_thread->attr) != 0) {
/* Insufficient memory to create a stack: */
ret = EAGAIN;
_thr_free(curthread, new_thread);
}
else if (((new_thread->attr.flags & PTHREAD_SCOPE_SYSTEM) != 0) &&
(((kse = _kse_alloc(curthread, 1)) == NULL)
|| ((kseg = _kseg_alloc(curthread)) == NULL))) {
/* Insufficient memory to create a new KSE/KSEG: */
ret = EAGAIN;
if (kse != NULL) {
kse->k_kcb->kcb_kmbx.km_flags |= KMF_DONE;
_kse_free(curthread, kse);
}
free_stack(&new_thread->attr);
_thr_free(curthread, new_thread);
}
else {
if (kseg != NULL) {
/* Add the KSE to the KSEG's list of KSEs. */
TAILQ_INSERT_HEAD(&kseg->kg_kseq, kse, k_kgqe);
kseg->kg_ksecount = 1;
kse->k_kseg = kseg;
kse->k_schedq = &kseg->kg_schedq;
}
/*
* Write a magic value to the thread structure
* to help identify valid ones:
*/
new_thread->magic = THR_MAGIC;
new_thread->slice_usec = -1;
new_thread->start_routine = start_routine;
new_thread->arg = arg;
new_thread->cancelflags = PTHREAD_CANCEL_ENABLE |
PTHREAD_CANCEL_DEFERRED;
/* No thread is wanting to join to this one: */
new_thread->joiner = NULL;
/* Initialize the signal frame: */
new_thread->curframe = NULL;
/*
* Initialize the machine context.
* Enter a critical region to get consistent context.
*/
crit = _kse_critical_enter();
THR_GETCONTEXT(&new_thread->tcb->tcb_tmbx.tm_context);
/* Initialize the thread for signals: */
new_thread->sigmask = curthread->sigmask;
_kse_critical_leave(crit);
new_thread->tcb->tcb_tmbx.tm_udata = new_thread;
new_thread->tcb->tcb_tmbx.tm_context.uc_sigmask =
new_thread->sigmask;
new_thread->tcb->tcb_tmbx.tm_context.uc_stack.ss_size =
new_thread->attr.stacksize_attr;
new_thread->tcb->tcb_tmbx.tm_context.uc_stack.ss_sp =
new_thread->attr.stackaddr_attr;
makecontext(&new_thread->tcb->tcb_tmbx.tm_context,
(void (*)(void))thread_start, 3, new_thread,
start_routine, arg);
/*
* Check if this thread is to inherit the scheduling
* attributes from its parent:
*/
if (new_thread->attr.sched_inherit == PTHREAD_INHERIT_SCHED) {
/*
* Copy the scheduling attributes.
* Lock the scheduling lock to get consistent
* scheduling parameters.
*/
THR_SCHED_LOCK(curthread, curthread);
new_thread->base_priority =
curthread->base_priority &
~THR_SIGNAL_PRIORITY;
new_thread->attr.prio =
curthread->base_priority &
~THR_SIGNAL_PRIORITY;
new_thread->attr.sched_policy =
curthread->attr.sched_policy;
THR_SCHED_UNLOCK(curthread, curthread);
} else {
/*
* Use just the thread priority, leaving the
* other scheduling attributes as their
* default values:
*/
new_thread->base_priority =
new_thread->attr.prio;
}
new_thread->active_priority = new_thread->base_priority;
new_thread->inherited_priority = 0;
/* Initialize the mutex queue: */
TAILQ_INIT(&new_thread->mutexq);
/* Initialise hooks in the thread structure: */
new_thread->specific = NULL;
new_thread->specific_data_count = 0;
new_thread->cleanup = NULL;
new_thread->flags = 0;
new_thread->continuation = NULL;
new_thread->wakeup_time.tv_sec = -1;
new_thread->lock_switch = 0;
sigemptyset(&new_thread->sigpend);
new_thread->check_pending = 0;
new_thread->locklevel = 0;
new_thread->rdlock_count = 0;
new_thread->sigstk.ss_sp = 0;
new_thread->sigstk.ss_size = 0;
new_thread->sigstk.ss_flags = SS_DISABLE;
new_thread->oldsigmask = NULL;
if (new_thread->attr.suspend == THR_CREATE_SUSPENDED) {
new_thread->state = PS_SUSPENDED;
new_thread->flags = THR_FLAGS_SUSPENDED;
}
else
new_thread->state = PS_RUNNING;
/*
* System scope threads have their own kse and
* kseg. Process scope threads are all hung
* off the main process kseg.
*/
if ((new_thread->attr.flags & PTHREAD_SCOPE_SYSTEM) == 0) {
new_thread->kseg = _kse_initial->k_kseg;
new_thread->kse = _kse_initial;
}
else {
kse->k_curthread = NULL;
kse->k_kseg->kg_flags |= KGF_SINGLE_THREAD;
new_thread->kse = kse;
new_thread->kseg = kse->k_kseg;
kse->k_kcb->kcb_kmbx.km_udata = kse;
kse->k_kcb->kcb_kmbx.km_curthread = NULL;
}
/*
* Schedule the new thread starting a new KSEG/KSE
* pair if necessary.
*/
ret = _thr_schedule_add(curthread, new_thread);
if (ret != 0)
free_thread(curthread, new_thread);
else {
/* Return a pointer to the thread structure: */
(*thread) = new_thread;
}
}
}
/* Return the status: */
return (ret);
}
static void
free_thread(struct pthread *curthread, struct pthread *thread)
{
free_stack(&thread->attr);
if ((thread->attr.flags & PTHREAD_SCOPE_SYSTEM) != 0) {
/* Free the KSE and KSEG. */
_kseg_free(thread->kseg);
_kse_free(curthread, thread->kse);
}
_thr_free(curthread, thread);
}
static int
create_stack(struct pthread_attr *pattr)
{
int ret;
/* Check if a stack was specified in the thread attributes: */
if ((pattr->stackaddr_attr) != NULL) {
pattr->guardsize_attr = 0;
pattr->flags |= THR_STACK_USER;
ret = 0;
}
else
ret = _thr_stack_alloc(pattr);
return (ret);
}
static void
free_stack(struct pthread_attr *pattr)
{
struct kse *curkse;
kse_critical_t crit;
if ((pattr->flags & THR_STACK_USER) == 0) {
crit = _kse_critical_enter();
curkse = _get_curkse();
KSE_LOCK_ACQUIRE(curkse, &_thread_list_lock);
/* Stack routines don't use malloc/free. */
_thr_stack_free(pattr);
KSE_LOCK_RELEASE(curkse, &_thread_list_lock);
_kse_critical_leave(crit);
}
}
static void
thread_start(struct pthread *curthread, void *(*start_routine) (void *),
void *arg)
{
/* Run the current thread's start routine with argument: */
pthread_exit(start_routine(arg));
/* This point should never be reached. */
PANIC("Thread has resumed after exit");
}