b5a8a15c2f
file descriptors needing to be polled (Doh!). Reported
by Dan Nelson <dnelson@emsphone.com>.
Don't install and start the scheduling timer until the
first thread is created. This prevents the overhead of
having a periodic scheduling signal in a single threaded
program. Reported by Dan Nelson <dnelson@emsphone.com>.
Allow builtin longjmps out of application installed
signal handlers without the need perform any post-handler
cleanup:
o Change signal handling to save the threads interrupted
context on the stack. The threads current context is
now always stored in the same place (in the pthread).
If and when a signal handler returns, the interrupted
context is copied back to the storage area in the pthread.
o Before calling invoking a signal handler for a thread,
back the thread out of any internal waiting queues
(mutex, CV, join, etc) to which it belongs.
Rework uthread_info.c a bit to make it easier to change
the format of a thread dump.
Use an alternal signal stack for the thread library's
signal handler. This allows us to fiddle with the main
threads stack without fear of it being in use.
Reviewed by: jasone
328 lines
9.6 KiB
C
328 lines
9.6 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 <stddef.h>
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#include <sys/time.h>
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#include <sys/param.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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static u_int64_t next_uniqueid = 1;
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#define OFF(f) offsetof(struct pthread, f)
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int _thread_next_offset = OFF(tle.tqe_next);
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int _thread_uniqueid_offset = OFF(uniqueid);
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int _thread_state_offset = OFF(state);
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int _thread_name_offset = OFF(name);
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int _thread_ctxtype_offset = OFF(ctxtype);
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int _thread_ctx_offset = OFF(ctx);
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#undef OFF
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int _thread_PS_RUNNING_value = PS_RUNNING;
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int _thread_PS_DEAD_value = PS_DEAD;
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int _thread_CTX_JB_NOSIG_value = CTX_JB_NOSIG;
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int _thread_CTX_JB_value = CTX_JB;
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int _thread_CTX_SJB_value = CTX_SJB;
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int _thread_CTX_UC_value = CTX_UC;
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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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struct itimerval itimer;
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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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/* 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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/* 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: */
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if (mmap(stack, PTHREAD_STACK_DEFAULT,
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PROT_READ | PROT_WRITE, MAP_STACK,
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-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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}
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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->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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new_thread->sigmask_seqno = 0;
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/* Initialize the signal frame: */
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new_thread->curframe = NULL;
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/* Initialise the jump buffer: */
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_setjmp(new_thread->ctx.jb);
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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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SET_RETURN_ADDR_JB(new_thread->ctx.jb, _thread_start);
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/* The stack starts high and builds down: */
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SET_STACK_JB(new_thread->ctx.jb,
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(long)new_thread->stack + pattr->stacksize_attr
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- sizeof(double));
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/* Initialize the rest of the frame: */
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new_thread->ctxtype = CTX_JB_NOSIG;
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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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~PTHREAD_SIGNAL_PRIORITY;
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new_thread->attr.prio =
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_thread_run->base_priority &
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~PTHREAD_SIGNAL_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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new_thread->continuation = 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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* Initialise the unique id which GDB uses to
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* track threads.
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*/
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new_thread->uniqueid = next_uniqueid++;
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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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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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if (f_gc != 0) {
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/* Install the scheduling timer: */
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itimer.it_interval.tv_sec = 0;
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itimer.it_interval.tv_usec = _clock_res_usec;
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itimer.it_value = itimer.it_interval;
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if (setitimer(_ITIMER_SCHED_TIMER, &itimer,
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NULL) != 0)
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PANIC("Cannot set interval timer");
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}
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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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