/* * 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. 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 REGENTS 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. * * $Id: uthread_create.c,v 1.13 1999/06/20 08:28:14 jb Exp $ */ #include #include #include #include #include #include #ifdef _PTHREAD_GSTACK #include #include #endif #ifdef _THREAD_SAFE #include #include #include "pthread_private.h" #include "libc_private.h" int pthread_create(pthread_t * thread, const pthread_attr_t * attr, void *(*start_routine) (void *), void *arg) { int f_gc = 0; int i; int ret = 0; int status; pthread_t gc_thread; pthread_t new_thread; pthread_attr_t pattr; void *stack; /* * Locking functions in libc are required when there are * threads other than the initial thread. */ __isthreaded = 1; /* Allocate memory for the thread structure: */ if ((new_thread = (pthread_t) malloc(sizeof(struct pthread))) == 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: */ pattr = &pthread_attr_default; } else { pattr = *attr; } /* Check if a stack was specified in the thread attributes: */ if ((stack = pattr->stackaddr_attr) != NULL) { } #ifdef _PTHREAD_GSTACK /* Allocate memory for a default-size stack: */ else if (pattr->stacksize_attr == PTHREAD_STACK_DEFAULT) { struct stack * spare_stack; /* Allocate or re-use a default-size stack. */ /* Use the garbage collector mutex for synchronization * of the spare stack list. * * XXX This may not be ideal. */ if (pthread_mutex_lock(&_gc_mutex) != 0) PANIC("Cannot lock gc mutex"); if (NULL != (spare_stack = SLIST_FIRST(&_stackq))) { /* Use the spare stack. */ SLIST_REMOVE_HEAD(&_stackq, qe); stack = sizeof(struct stack) + (void *) spare_stack - PTHREAD_STACK_DEFAULT; } else { /* Allocate a new stack. */ stack = _next_stack + PTHREAD_STACK_GUARD; /* Even if stack allocation fails, we don't want to try to use this location again, so unconditionally * decrement _next_stack. Under normal operating conditions, the most likely reason for an mmap() * error is a stack overflow of the adjacent thread stack. */ _next_stack -= (PTHREAD_STACK_DEFAULT + PTHREAD_STACK_GUARD); /* Red zone: */ if (MAP_FAILED == mmap(_next_stack, PTHREAD_STACK_GUARD, 0, MAP_ANON, -1, 0)) { ret = EAGAIN; free(new_thread); } /* Stack: */ else if (MAP_FAILED == mmap(stack, PTHREAD_STACK_DEFAULT, PROT_READ | PROT_WRITE, MAP_STACK, -1, 0)) { ret = EAGAIN; munmap(_next_stack, PTHREAD_STACK_GUARD); free(new_thread); } } /* Unlock the garbage collector mutex. */ if (pthread_mutex_unlock(&_gc_mutex) != 0) PANIC("Cannot unlock gc mutex"); } /* The user wants a stack of a particular size. Lets hope they really know what they want, and simply malloc the * stack. */ else if ((stack = (void *) malloc(pattr->stacksize_attr)) == NULL) { /* Insufficient memory to create a thread: */ ret = EAGAIN; free(new_thread); } #else /* Allocate memory for the stack: */ else if ((stack = (void *) malloc(pattr->stacksize_attr)) == NULL) { /* Insufficient memory to create a thread: */ ret = EAGAIN; free(new_thread); } #endif /* Check for errors: */ if (ret != 0) { } else { /* Initialise the thread structure: */ memset(new_thread, 0, sizeof(struct pthread)); new_thread->slice_usec = -1; new_thread->sig_saved = 0; new_thread->stack = stack; new_thread->start_routine = start_routine; new_thread->arg = arg; /* * Write a magic value to the thread structure * to help identify valid ones: */ new_thread->magic = PTHREAD_MAGIC; /* Initialise the thread for signals: */ new_thread->sigmask = _thread_run->sigmask; /* Initialise the jump buffer: */ setjmp(new_thread->saved_jmp_buf); /* * Set up new stack frame so that it looks like it * returned from a longjmp() to the beginning of * _thread_start(). */ #if defined(__FreeBSD__) #if defined(__alpha__) new_thread->saved_jmp_buf[0]._jb[2] = (long) _thread_start; new_thread->saved_jmp_buf[0]._jb[4 + R_RA] = 0; new_thread->saved_jmp_buf[0]._jb[4 + R_T12] = (long) _thread_start; #else new_thread->saved_jmp_buf[0]._jb[0] = (long) _thread_start; #endif #elif defined(__NetBSD__) #if defined(__alpha__) new_thread->saved_jmp_buf[2] = (long) _thread_start; new_thread->saved_jmp_buf[4 + R_RA] = 0; new_thread->saved_jmp_buf[4 + R_T12] = (long) _thread_start; #else new_thread->saved_jmp_buf[0] = (long) _thread_start; #endif #else #error "Don't recognize this operating system!" #endif /* The stack starts high and builds down: */ #if defined(__FreeBSD__) #if defined(__alpha__) new_thread->saved_jmp_buf[0]._jb[4 + R_SP] = (long) new_thread->stack + pattr->stacksize_attr - sizeof(double); #else new_thread->saved_jmp_buf[0]._jb[2] = (int) (new_thread->stack + pattr->stacksize_attr - sizeof(double)); #endif #elif defined(__NetBSD__) #if defined(__alpha__) new_thread->saved_jmp_buf[4 + R_SP] = (long) new_thread->stack + pattr->stacksize_attr - sizeof(double); #else new_thread->saved_jmp_buf[2] = (long) new_thread->stack + pattr->stacksize_attr - sizeof(double); #endif #else #error "Don't recognize this operating system!" #endif /* Copy the thread attributes: */ memcpy(&new_thread->attr, pattr, sizeof(struct pthread_attr)); /* * Check if this thread is to inherit the scheduling * attributes from its parent: */ if (new_thread->attr.flags & PTHREAD_INHERIT_SCHED) { /* Copy the scheduling attributes: */ new_thread->base_priority = _thread_run->base_priority; new_thread->attr.prio = _thread_run->base_priority; new_thread->attr.sched_policy = _thread_run->attr.sched_policy; } 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; /* Initialise the join queue for the new thread: */ TAILQ_INIT(&(new_thread->join_queue)); /* Initialize the mutex queue: */ TAILQ_INIT(&new_thread->mutexq); /* Initialise hooks in the thread structure: */ new_thread->specific_data = NULL; new_thread->cleanup = NULL; new_thread->flags = 0; new_thread->poll_data.nfds = 0; new_thread->poll_data.fds = NULL; /* * Defer signals to protect the scheduling queues * from access by the signal handler: */ _thread_kern_sig_defer(); /* * Check if the garbage collector thread * needs to be started. */ f_gc = (TAILQ_FIRST(&_thread_list) == _thread_initial); /* Add the thread to the linked list of all threads: */ TAILQ_INSERT_HEAD(&_thread_list, new_thread, tle); if (pattr->suspend == PTHREAD_CREATE_SUSPENDED) { new_thread->state = PS_SUSPENDED; PTHREAD_WAITQ_INSERT(new_thread); } else { new_thread->state = PS_RUNNING; PTHREAD_PRIOQ_INSERT_TAIL(new_thread); } /* * Undefer and handle pending signals, yielding * if necessary. */ _thread_kern_sig_undefer(); /* Return a pointer to the thread structure: */ (*thread) = new_thread; /* Schedule the new user thread: */ _thread_kern_sched(NULL); /* * Start a garbage collector thread * if necessary. */ if (f_gc && pthread_create(&gc_thread,NULL, _thread_gc,NULL) != 0) PANIC("Can't create gc thread"); } } /* Return the status: */ return (ret); } void _thread_start(void) { /* We just left the scheduler via longjmp: */ _thread_kern_in_sched = 0; /* Run the current thread's start routine with argument: */ pthread_exit(_thread_run->start_routine(_thread_run->arg)); /* This point should never be reached. */ PANIC("Thread has resumed after exit"); } #endif