7285bccf1a
eischen (Daniel Eischen) added wrappers to protect against cancled threads orphaning internal resources. the cancelability code is still a bit fuzzy but works for test programs of my own, OpenBSD's and some examples from ORA's books. add readdir_r to both libc and libc_r add some 'const' attributes to function parameters Reviewed by: eischen, jasone
326 lines
9.7 KiB
C
326 lines
9.7 KiB
C
/*
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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 <sys/time.h>
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#include <sys/types.h>
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#include <sys/mman.h>
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#ifdef _THREAD_SAFE
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#include <machine/reg.h>
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#include <pthread.h>
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#include "pthread_private.h"
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#include "libc_private.h"
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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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int f_gc = 0;
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int ret = 0;
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pthread_t gc_thread;
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pthread_t new_thread;
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pthread_attr_t pattr;
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void *stack;
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/*
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* Locking functions in libc are required when there are
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* threads other than the initial thread.
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*/
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__isthreaded = 1;
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/* Allocate memory for the thread structure: */
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if ((new_thread = (pthread_t) malloc(sizeof(struct pthread))) == 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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/* 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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pattr = &pthread_attr_default;
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} else {
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pattr = *attr;
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}
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/* Check if a stack was specified in the thread attributes: */
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if ((stack = pattr->stackaddr_attr) != NULL) {
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}
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/* Allocate memory for a default-size stack: */
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else if (pattr->stacksize_attr == PTHREAD_STACK_DEFAULT) {
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struct stack *spare_stack;
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/* Allocate or re-use a default-size stack. */
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/*
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* Use the garbage collector mutex for synchronization
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* of the spare stack list.
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*/
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if (pthread_mutex_lock(&_gc_mutex) != 0)
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PANIC("Cannot lock gc mutex");
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if ((spare_stack = SLIST_FIRST(&_stackq)) != NULL) {
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/* Use the spare stack. */
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SLIST_REMOVE_HEAD(&_stackq, qe);
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/* Unlock the garbage collector mutex. */
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if (pthread_mutex_unlock(&_gc_mutex) != 0)
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PANIC("Cannot unlock gc mutex");
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stack = sizeof(struct stack)
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+ (void *) spare_stack
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- PTHREAD_STACK_DEFAULT;
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} else {
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/* Unlock the garbage collector mutex. */
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if (pthread_mutex_unlock(&_gc_mutex) != 0)
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PANIC("Cannot unlock gc mutex");
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/* Allocate a new stack. */
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stack = _next_stack + PTHREAD_STACK_GUARD;
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/*
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* Even if stack allocation fails, we don't want
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* to try to use this location again, so
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* unconditionally decrement _next_stack. Under
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* normal operating conditions, the most likely
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* reason for an mmap() error is a stack
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* overflow of the adjacent thread stack.
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*/
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_next_stack -= (PTHREAD_STACK_DEFAULT
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+ PTHREAD_STACK_GUARD);
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/* Red zone: */
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if (mmap(_next_stack, PTHREAD_STACK_GUARD, 0,
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MAP_ANON, -1, 0) == MAP_FAILED) {
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ret = EAGAIN;
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free(new_thread);
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}
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/* Stack: */
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else if (mmap(stack,
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PTHREAD_STACK_DEFAULT,
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PROT_READ | PROT_WRITE,
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#ifdef __i386__
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MAP_STACK,
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#else
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MAP_ANON,
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#endif
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-1, 0) == MAP_FAILED) {
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ret = EAGAIN;
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munmap(_next_stack,
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PTHREAD_STACK_GUARD);
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free(new_thread);
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}
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}
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}
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/*
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* The user wants a stack of a particular size. Lets hope they
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* really know what they want, and simply malloc the stack.
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*/
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else if ((stack = (void *) malloc(pattr->stacksize_attr))
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== NULL) {
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/* Insufficient memory to create a thread: */
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ret = EAGAIN;
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free(new_thread);
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}
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/* Check for errors: */
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if (ret != 0) {
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} else {
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/* Initialise the thread structure: */
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memset(new_thread, 0, sizeof(struct pthread));
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new_thread->slice_usec = -1;
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new_thread->sig_saved = 0;
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new_thread->stack = stack;
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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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/*
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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 = PTHREAD_MAGIC;
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/* Initialise the thread for signals: */
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new_thread->sigmask = _thread_run->sigmask;
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/* Initialise the jump buffer: */
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setjmp(new_thread->saved_jmp_buf);
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/*
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* Set up new stack frame so that it looks like it
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* returned from a longjmp() to the beginning of
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* _thread_start().
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*/
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#if defined(__FreeBSD__)
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#if defined(__alpha__)
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new_thread->saved_jmp_buf[0]._jb[2] = (long) _thread_start;
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new_thread->saved_jmp_buf[0]._jb[4 + R_RA] = 0;
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new_thread->saved_jmp_buf[0]._jb[4 + R_T12] = (long) _thread_start;
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#else
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new_thread->saved_jmp_buf[0]._jb[0] = (long) _thread_start;
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#endif
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#elif defined(__NetBSD__)
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#if defined(__alpha__)
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new_thread->saved_jmp_buf[2] = (long) _thread_start;
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new_thread->saved_jmp_buf[4 + R_RA] = 0;
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new_thread->saved_jmp_buf[4 + R_T12] = (long) _thread_start;
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#else
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new_thread->saved_jmp_buf[0] = (long) _thread_start;
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#endif
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#else
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#error "Don't recognize this operating system!"
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#endif
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/* The stack starts high and builds down: */
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#if defined(__FreeBSD__)
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#if defined(__alpha__)
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new_thread->saved_jmp_buf[0]._jb[4 + R_SP] = (long) new_thread->stack + pattr->stacksize_attr - sizeof(double);
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#else
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new_thread->saved_jmp_buf[0]._jb[2] = (int) (new_thread->stack + pattr->stacksize_attr - sizeof(double));
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#endif
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#elif defined(__NetBSD__)
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#if defined(__alpha__)
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new_thread->saved_jmp_buf[4 + R_SP] = (long) new_thread->stack + pattr->stacksize_attr - sizeof(double);
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#else
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new_thread->saved_jmp_buf[2] = (long) new_thread->stack + pattr->stacksize_attr - sizeof(double);
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#endif
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#else
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#error "Don't recognize this operating system!"
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#endif
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/* Copy the thread attributes: */
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memcpy(&new_thread->attr, pattr, sizeof(struct pthread_attr));
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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) {
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/* Copy the scheduling attributes: */
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new_thread->base_priority
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= _thread_run->base_priority;
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new_thread->attr.prio
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= _thread_run->base_priority;
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new_thread->attr.sched_policy
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= _thread_run->attr.sched_policy;
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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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/* Initialise the join queue for the new thread: */
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TAILQ_INIT(&(new_thread->join_queue));
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/* Initialize the mutex queue: */
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TAILQ_INIT(&new_thread->mutexq);
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/* Initialise hooks in the thread structure: */
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new_thread->specific_data = NULL;
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new_thread->cleanup = NULL;
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new_thread->flags = 0;
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new_thread->poll_data.nfds = 0;
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new_thread->poll_data.fds = NULL;
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/*
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* Defer signals to protect the scheduling queues
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* from access by the signal handler:
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*/
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_thread_kern_sig_defer();
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/*
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* Check if the garbage collector thread
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* needs to be started.
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*/
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f_gc = (TAILQ_FIRST(&_thread_list) == _thread_initial);
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/* Add the thread to the linked list of all threads: */
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TAILQ_INSERT_HEAD(&_thread_list, new_thread, tle);
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if (pattr->suspend == PTHREAD_CREATE_SUSPENDED) {
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new_thread->state = PS_SUSPENDED;
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PTHREAD_WAITQ_INSERT(new_thread);
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} else {
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new_thread->state = PS_RUNNING;
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PTHREAD_PRIOQ_INSERT_TAIL(new_thread);
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}
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/*
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* Undefer and handle pending signals, yielding
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* if necessary.
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*/
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_thread_kern_sig_undefer();
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/* Return a pointer to the thread structure: */
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(*thread) = new_thread;
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/* Schedule the new user thread: */
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_thread_kern_sched(NULL);
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/*
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* Start a garbage collector thread
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* if necessary.
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*/
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if (f_gc && pthread_create(&gc_thread,NULL,
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_thread_gc,NULL) != 0)
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PANIC("Can't create gc 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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void
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_thread_start(void)
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{
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/* We just left the scheduler via longjmp: */
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_thread_kern_in_sched = 0;
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/* Run the current thread's start routine with argument: */
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pthread_exit(_thread_run->start_routine(_thread_run->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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#endif
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