/* $NetBSD: pthread.c,v 1.1.2.28 2002/10/07 19:30:32 nathanw Exp $ */ /*- * Copyright (c) 2001 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Nathan J. Williams. * * 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 the NetBSD * Foundation, Inc. and its contributors. * 4. Neither the name of The NetBSD Foundation nor the names of its * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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. */ #include #include #include #include #include #include #include #include #include #include "sched.h" #include "pthread.h" #include "pthread_int.h" static void pthread__create_tramp(void *(*start)(void *), void *arg); static pthread_attr_t pthread_default_attr; pthread_spin_t allqueue_lock; struct pthread_queue_t allqueue; static int nthreads; pthread_spin_t deadqueue_lock; struct pthread_queue_t deadqueue; struct pthread_queue_t reidlequeue; extern struct pthread_queue_t runqueue; extern struct pthread_queue_t idlequeue; extern pthread_spin_t runqueue_lock; int pthread__started; static int nextthread; pthread_spin_t nextthread_lock; pthread_ops_t pthread_ops = { pthread_mutex_init, pthread_mutex_lock, pthread_mutex_trylock, pthread_mutex_unlock, pthread_mutex_destroy, pthread_mutexattr_init, pthread_mutexattr_destroy, pthread_cond_init, pthread_cond_signal, pthread_cond_broadcast, pthread_cond_wait, pthread_cond_timedwait, pthread_cond_destroy, pthread_condattr_init, pthread_condattr_destroy, pthread_key_create, pthread_setspecific, pthread_getspecific, pthread_key_delete, pthread_once, pthread_self, pthread_sigmask, pthread__errno }; /* * This needs to be started by the library loading code, before main() * gets to run, for various things that use the state of the initial thread * to work properly (thread-specific data is an application-visible example; * spinlock counts for mutexes is an internal example). */ void pthread_init(void) { pthread_t first; extern int __isthreaded; extern pthread_ops_t *__libc_pthread_ops; #ifdef PTHREAD__DEBUG pthread__debug_init(); #endif /* Basic data structure setup */ pthread_attr_init(&pthread_default_attr); PTQ_INIT(&allqueue); PTQ_INIT(&deadqueue); PTQ_INIT(&reidlequeue); PTQ_INIT(&runqueue); PTQ_INIT(&idlequeue); /* Create the thread structure corresponding to main() */ pthread__initmain(&first); pthread__initthread(first, first); first->pt_state = PT_STATE_RUNNING; sigprocmask(0, NULL, &first->pt_sigmask); PTQ_INSERT_HEAD(&allqueue, first, pt_allq); /* Start subsystems */ pthread__alarm_init(); pthread__signal_init(); PTHREAD_MD_INIT /* Tell libc that we're here and it should role-play accordingly. */ __libc_pthread_ops = &pthread_ops; __isthreaded = 1; } static void pthread__start(void) { pthread_t self, idle; int i, ret; self = pthread__self(); /* should be the "main()" thread */ /* Create idle threads */ for (i = 0; i < NIDLETHREADS; i++) { ret = pthread__stackalloc(&idle); if (ret != 0) err(1, "Couldn't allocate stack for idle thread!"); pthread__initthread(self, idle); sigfillset(&idle->pt_sigmask); PTQ_INSERT_HEAD(&allqueue, idle, pt_allq); pthread__sched_idle(self, idle); } nthreads = 1; /* Start up the SA subsystem */ pthread__sa_start(); } /* General-purpose thread data structure sanitization. */ void pthread__initthread(pthread_t self, pthread_t t) { int id; pthread_spinlock(self, &nextthread_lock); id = nextthread; nextthread++; pthread_spinunlock(self, &nextthread_lock); t->pt_num = id; t->pt_magic = PT_MAGIC; t->pt_type = PT_THREAD_NORMAL; t->pt_state = PT_STATE_RUNNABLE; pthread_lockinit(&t->pt_statelock); t->pt_spinlocks = 0; t->pt_next = NULL; t->pt_exitval = NULL; t->pt_flags = 0; t->pt_cancel = 0; t->pt_errno = 0; t->pt_parent = NULL; t->pt_heldlock = NULL; t->pt_switchto = NULL; t->pt_sleepuc = NULL; sigemptyset(&t->pt_siglist); sigemptyset(&t->pt_sigmask); pthread_lockinit(&t->pt_siglock); PTQ_INIT(&t->pt_joiners); pthread_lockinit(&t->pt_join_lock); PTQ_INIT(&t->pt_cleanup_stack); memset(&t->pt_specific, 0, sizeof(int) * PTHREAD_KEYS_MAX); #ifdef PTHREAD__DEBUG t->blocks = 0; t->preempts = 0; t->rescheds = 0; #endif } int pthread_create(pthread_t *thread, const pthread_attr_t *attr, void *(*startfunc)(void *), void *arg) { pthread_t self, newthread; pthread_attr_t nattr; int ret; PTHREADD_ADD(PTHREADD_CREATE); assert(thread != NULL); /* * It's okay to check this without a lock because there can * only be one thread before it becomes true. */ if (pthread__started == 0) { pthread__start(); pthread__started = 1; } if (attr == NULL) nattr = pthread_default_attr; else if (((attr != NULL) && (attr->pta_magic == PT_ATTR_MAGIC))) nattr = *attr; else return EINVAL; self = pthread__self(); pthread_spinlock(self, &deadqueue_lock); if (!PTQ_EMPTY(&deadqueue)) { newthread= PTQ_FIRST(&deadqueue); PTQ_REMOVE(&deadqueue, newthread, pt_allq); pthread_spinunlock(self, &deadqueue_lock); } else { pthread_spinunlock(self, &deadqueue_lock); /* Set up a stack and allocate space for a pthread_st. */ ret = pthread__stackalloc(&newthread); if (ret != 0) return ret; } /* 2. Set up state. */ pthread__initthread(self, newthread); newthread->pt_flags = nattr.pta_flags; newthread->pt_sigmask = self->pt_sigmask; /* * 3. Set up context. * * The pt_uc pointer points to a location safely below the * stack start; this is arranged by pthread__stackalloc(). */ getcontext(newthread->pt_uc); newthread->pt_uc->uc_stack = newthread->pt_stack; newthread->pt_uc->uc_link = NULL; makecontext(newthread->pt_uc, pthread__create_tramp, 2, startfunc, arg); /* 4. Add to list of all threads. */ pthread_spinlock(self, &allqueue_lock); PTQ_INSERT_HEAD(&allqueue, newthread, pt_allq); nthreads++; pthread_spinunlock(self, &allqueue_lock); /* 5. Put on run queue. */ pthread__sched(self, newthread); *thread = newthread; return 0; } static void pthread__create_tramp(void *(*start)(void *), void *arg) { void *retval; retval = start(arg); pthread_exit(retval); /* NOTREACHED */ } /* * Other threads will switch to the idle thread so that they * can dispose of any awkward locks or recycle upcall state. */ void pthread__idle(void) { pthread_t self; PTHREADD_ADD(PTHREADD_IDLE); self = pthread__self(); /* * The drill here is that we want to yield the processor, * but for the thread itself to be recovered, we need to be on * a list somewhere for the thread system to know about us. */ pthread_spinlock(self, &deadqueue_lock); PTQ_INSERT_TAIL(&reidlequeue, self, pt_runq); self->pt_flags |= PT_FLAG_IDLED; pthread_spinunlock(self, &deadqueue_lock); /* * If we get to run this, then no preemption has happened * (because the upcall handler will not contiune an idle thread with * PT_FLAG_IDLED set), and so we can yield the processor safely. */ sa_yield(); } void pthread_exit(void *retval) { pthread_t self, joiner; struct pt_clean_t *cleanup; int nt; self = pthread__self(); /* Disable cancellability. */ self->pt_flags |= PT_FLAG_CS_DISABLED; /* Call any cancellation cleanup handlers */ while (!PTQ_EMPTY(&self->pt_cleanup_stack)) { cleanup = PTQ_FIRST(&self->pt_cleanup_stack); PTQ_REMOVE(&self->pt_cleanup_stack, cleanup, ptc_next); (*cleanup->ptc_cleanup)(cleanup->ptc_arg); } /* Perform cleanup of thread-specific data */ pthread__destroy_tsd(self); self->pt_exitval = retval; pthread_spinlock(self, &self->pt_join_lock); if (self->pt_flags & PT_FLAG_DETACHED) { pthread_spinunlock(self, &self->pt_join_lock); pthread_spinlock(self, &allqueue_lock); PTQ_REMOVE(&allqueue, self, pt_allq); nthreads--; nt = nthreads; pthread_spinunlock(self, &allqueue_lock); self->pt_state = PT_STATE_DEAD; if (nt == 0) { /* Whoah, we're the last one. Time to go. */ exit(0); } /* Yeah, yeah, doing work while we're dead is tacky. */ pthread_spinlock(self, &deadqueue_lock); PTQ_INSERT_HEAD(&deadqueue, self, pt_allq); pthread__block(self, &deadqueue_lock); } else { pthread_spinlock(self, &allqueue_lock); nthreads--; nt = nthreads; self->pt_state = PT_STATE_ZOMBIE; pthread_spinunlock(self, &allqueue_lock); if (nt == 0) { /* Whoah, we're the last one. Time to go. */ exit(0); } /* Wake up all the potential joiners. Only one can win. * (Can you say "Thundering Herd"? I knew you could.) */ PTQ_FOREACH(joiner, &self->pt_joiners, pt_sleep) pthread__sched(self, joiner); pthread__block(self, &self->pt_join_lock); } /* NOTREACHED */ assert(0); exit(1); } int pthread_join(pthread_t thread, void **valptr) { pthread_t self; if ((thread == NULL) || (thread->pt_magic != PT_MAGIC)) return EINVAL; self = pthread__self(); if (thread == self) return EDEADLK; pthread_spinlock(self, &thread->pt_join_lock); if (thread->pt_flags & PT_FLAG_DETACHED) { pthread_spinunlock(self, &thread->pt_join_lock); return EINVAL; } if ((thread->pt_state != PT_STATE_ZOMBIE) && (thread->pt_state != PT_STATE_DEAD)) { /* * "I'm not dead yet!" * "You will be soon enough." */ pthread_spinlock(self, &self->pt_statelock); if (self->pt_cancel) { pthread_spinunlock(self, &self->pt_statelock); pthread_spinunlock(self, &thread->pt_join_lock); pthread_exit(PTHREAD_CANCELED); } self->pt_state = PT_STATE_BLOCKED_QUEUE; self->pt_sleepobj = thread; self->pt_sleepq = &thread->pt_joiners; self->pt_sleeplock = &thread->pt_join_lock; pthread_spinunlock(self, &self->pt_statelock); PTQ_INSERT_TAIL(&thread->pt_joiners, self, pt_sleep); pthread__block(self, &thread->pt_join_lock); pthread_spinlock(self, &thread->pt_join_lock); } if ((thread->pt_state == PT_STATE_DEAD) || (thread->pt_flags & PT_FLAG_DETACHED)) { /* Someone beat us to the join, or called pthread_detach(). */ pthread_spinunlock(self, &thread->pt_join_lock); return ESRCH; } /* All ours. */ thread->pt_state = PT_STATE_DEAD; pthread_spinunlock(self, &thread->pt_join_lock); if (valptr != NULL) *valptr = thread->pt_exitval; /* Cleanup time. Move the dead thread from allqueue to the deadqueue */ pthread_spinlock(self, &allqueue_lock); PTQ_REMOVE(&allqueue, thread, pt_allq); pthread_spinunlock(self, &allqueue_lock); pthread_spinlock(self, &deadqueue_lock); PTQ_INSERT_HEAD(&deadqueue, thread, pt_allq); pthread_spinunlock(self, &deadqueue_lock); return 0; } int pthread_equal(pthread_t t1, pthread_t t2) { /* Nothing special here. */ return (t1 == t2); } int pthread_detach(pthread_t thread) { pthread_t self, joiner; if ((thread == NULL) || (thread->pt_magic != PT_MAGIC)) return EINVAL; self = pthread__self(); pthread_spinlock(self, &thread->pt_join_lock); if (thread->pt_flags & PT_FLAG_DETACHED) { pthread_spinunlock(self, &thread->pt_join_lock); return EINVAL; } thread->pt_flags |= PT_FLAG_DETACHED; /* Any joiners have to be punted now. */ PTQ_FOREACH(joiner, &thread->pt_joiners, pt_sleep) pthread__sched(self, joiner); pthread_spinunlock(self, &thread->pt_join_lock); return 0; } int sched_yield(void) { /* XXX implement me */ return 0; } int pthread_attr_init(pthread_attr_t *attr) { attr->pta_magic = PT_ATTR_MAGIC; attr->pta_flags = 0; return 0; } int pthread_attr_destroy(pthread_attr_t *attr) { return 0; } int pthread_attr_getdetachstate(pthread_attr_t *attr, int *detachstate) { if ((attr == NULL) || (attr->pta_magic != PT_ATTR_MAGIC)) return EINVAL; *detachstate = (attr->pta_flags & PT_FLAG_DETACHED); return 0; } int pthread_attr_setdetachstate(pthread_attr_t *attr, int detachstate) { if ((attr == NULL) || (attr->pta_magic != PT_ATTR_MAGIC)) return EINVAL; switch (detachstate) { case PTHREAD_CREATE_JOINABLE: attr->pta_flags &= ~PT_FLAG_DETACHED; break; case PTHREAD_CREATE_DETACHED: attr->pta_flags |= PT_FLAG_DETACHED; break; default: return EINVAL; } return 0; } int pthread_attr_setschedparam(pthread_attr_t *attr, const struct sched_param *param) { if ((attr == NULL) || (attr->pta_magic != PT_ATTR_MAGIC)) return EINVAL; if (param == NULL) return EINVAL; if (param->sched_priority != 0) return EINVAL; return 0; } int pthread_attr_getschedparam(pthread_attr_t *attr, struct sched_param *param) { if ((attr == NULL) || (attr->pta_magic != PT_ATTR_MAGIC)) return EINVAL; if (param == NULL) return EINVAL; param->sched_priority = 0; return 0; } /* * XXX There should be a way for applications to use the efficent * inline version, but there are opacity/namespace issues. */ pthread_t pthread_self(void) { return pthread__self(); } int pthread_cancel(pthread_t thread) { pthread_t self; int flags; if (!(thread->pt_state == PT_STATE_RUNNING || thread->pt_state == PT_STATE_RUNNABLE || thread->pt_state == PT_STATE_BLOCKED_QUEUE || thread->pt_state == PT_STATE_BLOCKED_SYS)) return ESRCH; self = pthread__self(); flags = thread->pt_flags; flags |= PT_FLAG_CS_PENDING; if ((flags & PT_FLAG_CS_DISABLED) == 0) { thread->pt_cancel = 1; pthread_spinlock(self, &thread->pt_statelock); if (thread->pt_state == PT_STATE_BLOCKED_SYS) { /* * It's sleeping in the kernel. If we can wake * it up, it will notice the cancellation when * it returns. If it doesn't wake up when we * make this call, then it's blocked * uninterruptably in the kernel, and there's * not much to be done about it. */ _lwp_wakeup(thread->pt_blockedlwp); } else if (thread->pt_state == PT_STATE_BLOCKED_QUEUE) { /* * We're blocked somewhere (pthread__block() * was called. Cause it to wake up and the * caller will check for the cancellation. */ pthread_spinlock(self, thread->pt_sleeplock); PTQ_REMOVE(thread->pt_sleepq, thread, pt_sleep); pthread_spinunlock(self, thread->pt_sleeplock); pthread__sched(self, thread); } else { /* * Nothing. The target thread is running and will * notice at the next deferred cancellation point. */ } pthread_spinunlock(self, &thread->pt_statelock); } thread->pt_flags = flags; return 0; } int pthread_setcancelstate(int state, int *oldstate) { pthread_t self; int flags; self = pthread__self(); flags = self->pt_flags; if (oldstate != NULL) { if (flags & PT_FLAG_CS_DISABLED) *oldstate = PTHREAD_CANCEL_DISABLE; else *oldstate = PTHREAD_CANCEL_ENABLE; } if (state == PTHREAD_CANCEL_DISABLE) flags |= PT_FLAG_CS_DISABLED; else if (state == PTHREAD_CANCEL_ENABLE) { flags &= ~PT_FLAG_CS_DISABLED; /* * If a cancellation was requested while cancellation * was disabled, note that fact for future * cancellation tests. */ if (flags & PT_FLAG_CS_PENDING) { self->pt_cancel = 1; /* This is not a deferred cancellation point. */ if (flags & PT_FLAG_CS_ASYNC) pthread_exit(PTHREAD_CANCELED); } } else return EINVAL; self->pt_flags = flags; return 0; } int pthread_setcanceltype(int type, int *oldtype) { pthread_t self; int flags; self = pthread__self(); flags = self->pt_flags; if (oldtype != NULL) { if (flags & PT_FLAG_CS_ASYNC) *oldtype = PTHREAD_CANCEL_ASYNCHRONOUS; else *oldtype = PTHREAD_CANCEL_DEFERRED; } if (type == PTHREAD_CANCEL_ASYNCHRONOUS) { flags |= PT_FLAG_CS_ASYNC; if (self->pt_cancel) pthread_exit(PTHREAD_CANCELED); } else if (type == PTHREAD_CANCEL_DEFERRED) flags &= ~PT_FLAG_CS_ASYNC; else return EINVAL; self->pt_flags = flags; return 0; } void pthread_testcancel() { pthread_t self; self = pthread__self(); if (self->pt_cancel) pthread_exit(PTHREAD_CANCELED); } void pthread__testcancel(pthread_t self) { if (self->pt_cancel) pthread_exit(PTHREAD_CANCELED); } void pthread__cleanup_push(void (*cleanup)(void *), void *arg, void *store) { pthread_t self; struct pt_clean_t *entry; self = pthread__self(); entry = store; entry->ptc_cleanup = cleanup; entry->ptc_arg = arg; PTQ_INSERT_HEAD(&self->pt_cleanup_stack, entry, ptc_next); } void pthread__cleanup_pop(int ex, void *store) { pthread_t self; struct pt_clean_t *entry; self = pthread__self(); entry = store; PTQ_REMOVE(&self->pt_cleanup_stack, entry, ptc_next); if (ex) (*entry->ptc_cleanup)(entry->ptc_arg); } int * pthread__errno(void) { pthread_t self; self = pthread__self(); return &(self->pt_errno); }