/* * Copyright (c) 2003 Daniel M. Eischen * Copyright (c) 1995-1998 John Birrell * 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. 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. * * $FreeBSD$ */ #include "namespace.h" #include #include #include #include #include #include #include #include #include #include "un-namespace.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 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->tlflags = 0; new_thread->sigbackout = NULL; 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 __unused, 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"); }