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NetBSD/lib/libpthread/pthread.c

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/* $NetBSD: pthread.c,v 1.32 2003/12/31 16:45:48 cl Exp $ */
/*-
* Copyright (c) 2001,2002,2003 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 <sys/cdefs.h>
__RCSID("$NetBSD: pthread.c,v 1.32 2003/12/31 16:45:48 cl Exp $");
#include <err.h>
#include <errno.h>
#include <lwp.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <ucontext.h>
#include <unistd.h>
#include <sched.h>
#include "pthread.h"
#include "pthread_int.h"
#ifdef PTHREAD_MAIN_DEBUG
#define SDPRINTF(x) DPRINTF(x)
#else
#define SDPRINTF(x)
#endif
static void pthread__create_tramp(void *(*start)(void *), void *arg);
int pthread__started;
pthread_spin_t pthread__allqueue_lock;
struct pthread_queue_t pthread__allqueue;
pthread_spin_t pthread__deadqueue_lock;
struct pthread_queue_t pthread__deadqueue;
struct pthread_queue_t pthread__reidlequeue;
static int nthreads;
static int nextthread;
static pthread_spin_t nextthread_lock;
static pthread_attr_t pthread_default_attr;
enum {
DIAGASSERT_ABORT = 1<<0,
DIAGASSERT_STDERR = 1<<1,
DIAGASSERT_SYSLOG = 1<<2
};
static int pthread__diagassert = DIAGASSERT_ABORT | DIAGASSERT_STDERR;
pthread_spin_t pthread__runqueue_lock;
struct pthread_queue_t pthread__runqueue;
struct pthread_queue_t pthread__idlequeue;
struct pthread_queue_t pthread__suspqueue;
__strong_alias(__libc_thr_self,pthread_self)
__strong_alias(__libc_thr_create,pthread_create)
__strong_alias(__libc_thr_exit,pthread_exit)
__strong_alias(__libc_thr_errno,pthread__errno)
__strong_alias(__libc_thr_setcancelstate,pthread_setcancelstate)
/*
* Static library kludge. Place a reference to a symbol any library
* file which does not already have a reference here.
*/
extern int pthread__cancel_stub_binder;
extern int pthread__sched_binder;
extern struct pthread_queue_t pthread__nanosleeping;
void *pthread__static_lib_binder[] = {
&pthread__cancel_stub_binder,
pthread_cond_init,
pthread_mutex_init,
pthread_rwlock_init,
pthread_barrier_init,
pthread_key_create,
pthread_setspecific,
&pthread__sched_binder,
&pthread__nanosleeping
};
/*
* 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;
char *p;
extern int __isthreaded;
/* Initialize locks first; they're needed elsewhere. */
pthread__lockprim_init();
/* Basic data structure setup */
pthread_attr_init(&pthread_default_attr);
PTQ_INIT(&pthread__allqueue);
PTQ_INIT(&pthread__deadqueue);
PTQ_INIT(&pthread__reidlequeue);
PTQ_INIT(&pthread__runqueue);
PTQ_INIT(&pthread__idlequeue);
nthreads = 1;
/* 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(&pthread__allqueue, first, pt_allq);
/* Start subsystems */
pthread__signal_init();
PTHREAD_MD_INIT
#ifdef PTHREAD__DEBUG
pthread__debug_init();
#endif
for (p = getenv("PTHREAD_DIAGASSERT"); p && *p; p++) {
switch (*p) {
case 'a':
pthread__diagassert |= DIAGASSERT_ABORT;
break;
case 'A':
pthread__diagassert &= ~DIAGASSERT_ABORT;
break;
case 'e':
pthread__diagassert |= DIAGASSERT_STDERR;
break;
case 'E':
pthread__diagassert &= ~DIAGASSERT_STDERR;
break;
case 'l':
pthread__diagassert |= DIAGASSERT_SYSLOG;
break;
case 'L':
pthread__diagassert &= ~DIAGASSERT_SYSLOG;
break;
}
}
/* Tell libc that we're here and it should role-play accordingly. */
__isthreaded = 1;
}
static void
pthread__child_callback(void)
{
/*
* Clean up data structures that a forked child process might
* trip over. Note that if threads have been created (causing
* this handler to be registered) the standards say that the
* child will trigger undefined behavior if it makes any
* pthread_* calls (or any other calls that aren't
* async-signal-safe), so we don't really have to clean up
* much. Anything that permits some pthread_* calls to work is
* merely being polite.
*/
pthread__started = 0;
}
static void
pthread__start(void)
{
pthread_t self, idle;
int i, ret;
self = pthread__self(); /* should be the "main()" thread */
/*
* Per-process timers are cleared by fork(); despite the
* various restrictions on fork() and threads, it's legal to
* fork() before creating any threads.
*/
pthread__alarm_init();
pthread_atfork(NULL, NULL, pthread__child_callback);
/* 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);
idle->pt_type = PT_THREAD_IDLE;
PTQ_INSERT_HEAD(&pthread__allqueue, idle, pt_allq);
pthread__sched_idle(self, idle);
}
/* Start up the SA subsystem */
pthread__sa_start();
SDPRINTF(("(pthread__start %p) Started.\n", self));
}
/* 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);
pthread_lockinit(&t->pt_flaglock);
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_trapuc = 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);
t->pt_name = NULL;
#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;
struct pthread_attr_private *p;
char *name;
int ret;
PTHREADD_ADD(PTHREADD_CREATE);
/*
* 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->pta_magic == PT_ATTR_MAGIC)
nattr = *attr;
else
return EINVAL;
/* Fetch misc. attributes from the attr structure. */
name = NULL;
if ((p = nattr.pta_private) != NULL)
if (p->ptap_name[0] != '\0')
if ((name = strdup(p->ptap_name)) == NULL)
return ENOMEM;
self = pthread__self();
pthread_spinlock(self, &pthread__deadqueue_lock);
if (!PTQ_EMPTY(&pthread__deadqueue)) {
newthread = PTQ_FIRST(&pthread__deadqueue);
PTQ_REMOVE(&pthread__deadqueue, newthread, pt_allq);
pthread_spinunlock(self, &pthread__deadqueue_lock);
} else {
pthread_spinunlock(self, &pthread__deadqueue_lock);
/* Set up a stack and allocate space for a pthread_st. */
ret = pthread__stackalloc(&newthread);
if (ret != 0) {
if (name)
free(name);
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 misc. attributes. */
newthread->pt_name = name;
/*
* 4. Set up context.
*
* The pt_uc pointer points to a location safely below the
* stack start; this is arranged by pthread__stackalloc().
*/
_INITCONTEXT_U(newthread->pt_uc);
#ifdef PTHREAD_MACHINE_HAS_ID_REGISTER
pthread__uc_id(newthread->pt_uc) = newthread;
#endif
newthread->pt_uc->uc_stack = newthread->pt_stack;
newthread->pt_uc->uc_link = NULL;
makecontext(newthread->pt_uc, pthread__create_tramp, 2,
startfunc, arg);
/* 5. Add to list of all threads. */
pthread_spinlock(self, &pthread__allqueue_lock);
PTQ_INSERT_HEAD(&pthread__allqueue, newthread, pt_allq);
nthreads++;
pthread_spinunlock(self, &pthread__allqueue_lock);
SDPRINTF(("(pthread_create %p) Created new thread %p (name pointer %p).\n", self, newthread, newthread->pt_name));
/* 6. Put on appropriate queue. */
if (newthread->pt_flags & PT_FLAG_SUSPENDED) {
pthread_spinlock(self, &newthread->pt_statelock);
pthread__suspend(self, newthread);
pthread_spinunlock(self, &newthread->pt_statelock);
} else
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*/
pthread__abort();
}
int
pthread_suspend_np(pthread_t thread)
{
pthread_t self = pthread__self();
if (self == thread) {
fprintf(stderr, "suspend_np: can't suspend self\n");
return EDEADLK;
}
SDPRINTF(("(pthread_suspend_np %p) Suspend thread %p (state %d).\n",
self, thread, thread->pt_state));
pthread_spinlock(self, &thread->pt_statelock);
if (thread->pt_blockgen != thread->pt_unblockgen) {
/* XXX flaglock? */
thread->pt_flags |= PT_FLAG_SUSPENDED;
pthread_spinunlock(self, &thread->pt_statelock);
return 0;
}
switch (thread->pt_state) {
case PT_STATE_RUNNING:
pthread__abort(); /* XXX */
break;
case PT_STATE_SUSPENDED:
pthread_spinunlock(self, &thread->pt_statelock);
return 0;
case PT_STATE_RUNNABLE:
pthread_spinlock(self, &pthread__runqueue_lock);
PTQ_REMOVE(&pthread__runqueue, thread, pt_runq);
pthread_spinunlock(self, &pthread__runqueue_lock);
break;
case PT_STATE_BLOCKED_QUEUE:
pthread_spinlock(self, thread->pt_sleeplock);
PTQ_REMOVE(thread->pt_sleepq, thread, pt_sleep);
pthread_spinunlock(self, thread->pt_sleeplock);
break;
default:
break; /* XXX */
}
pthread__suspend(self, thread);
pthread_spinunlock(self, &thread->pt_statelock);
return 0;
}
int
pthread_resume_np(pthread_t thread)
{
pthread_t self = pthread__self();
SDPRINTF(("(pthread_resume_np %p) Resume thread %p (state %d).\n",
self, thread, thread->pt_state));
pthread_spinlock(self, &thread->pt_statelock);
/* XXX flaglock? */
thread->pt_flags &= ~PT_FLAG_SUSPENDED;
if (thread->pt_state == PT_STATE_SUSPENDED) {
pthread_spinlock(self, &pthread__runqueue_lock);
PTQ_REMOVE(&pthread__suspqueue, thread, pt_runq);
pthread_spinunlock(self, &pthread__runqueue_lock);
pthread__sched(self, thread);
}
pthread_spinunlock(self, &thread->pt_statelock);
return 0;
}
/*
* 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();
SDPRINTF(("(pthread__idle %p).\n", 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, &pthread__deadqueue_lock);
PTQ_INSERT_TAIL(&pthread__reidlequeue, self, pt_runq);
/* Don't need a flag lock; nothing else has a handle on this thread */
self->pt_flags |= PT_FLAG_IDLED;
pthread_spinunlock(self, &pthread__deadqueue_lock);
/*
* If we get to run this, then no preemption has happened
* (because the upcall handler will not continue an idle thread with
* PT_FLAG_IDLED set), and so we can yield the processor safely.
*/
SDPRINTF(("(pthread__idle %p) yielding.\n", self));
sa_yield();
/* NOTREACHED */
self->pt_spinlocks++; /* XXX make sure we get to finish the assert! */
SDPRINTF(("(pthread__idle %p) Returned! Error.\n", self));
pthread__abort();
}
void
pthread_exit(void *retval)
{
pthread_t self;
struct pt_clean_t *cleanup;
char *name;
int nt, flags;
self = pthread__self();
SDPRINTF(("(pthread_exit %p) Exiting (status %p, flags %x, cancel %d).\n", self, retval, self->pt_flags, self->pt_cancel));
/* Disable cancellability. */
pthread_spinlock(self, &self->pt_flaglock);
self->pt_flags |= PT_FLAG_CS_DISABLED;
flags = self->pt_flags;
self->pt_cancel = 0;
pthread_spinunlock(self, &self->pt_flaglock);
/* 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;
if (flags & PT_FLAG_DETACHED) {
name = self->pt_name;
self->pt_name = NULL;
if (name != NULL)
free(name);
pthread_spinlock(self, &pthread__allqueue_lock);
PTQ_REMOVE(&pthread__allqueue, self, pt_allq);
nthreads--;
nt = nthreads;
pthread_spinunlock(self, &pthread__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, &pthread__deadqueue_lock);
PTQ_INSERT_HEAD(&pthread__deadqueue, self, pt_allq);
pthread__block(self, &pthread__deadqueue_lock);
} else {
/* Note: name will be freed by the joiner. */
pthread_spinlock(self, &self->pt_join_lock);
pthread_spinlock(self, &pthread__allqueue_lock);
nthreads--;
nt = nthreads;
self->pt_state = PT_STATE_ZOMBIE;
pthread_spinunlock(self, &pthread__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.)
*/
pthread__sched_sleepers(self, &self->pt_joiners);
pthread__block(self, &self->pt_join_lock);
}
/*NOTREACHED*/
pthread__abort();
exit(1);
}
int
pthread_join(pthread_t thread, void **valptr)
{
pthread_t self;
char *name;
int num;
self = pthread__self();
SDPRINTF(("(pthread_join %p) Joining %p.\n", self, thread));
if (pthread__find(self, thread) != 0)
return ESRCH;
if (thread->pt_magic != PT_MAGIC)
return EINVAL;
if (thread == self)
return EDEADLK;
pthread_spinlock(self, &thread->pt_flaglock);
if (thread->pt_flags & PT_FLAG_DETACHED) {
pthread_spinunlock(self, &thread->pt_flaglock);
return EINVAL;
}
num = thread->pt_num;
pthread_spinlock(self, &thread->pt_join_lock);
while (thread->pt_state != PT_STATE_ZOMBIE) {
if ((thread->pt_state == PT_STATE_DEAD) ||
(thread->pt_flags & PT_FLAG_DETACHED) ||
(thread->pt_num != num)) {
/*
* Another thread beat us to the join, or called
* pthread_detach(). If num didn't match, the
* thread died and was recycled before we got
* another chance to run.
*/
pthread_spinunlock(self, &thread->pt_join_lock);
pthread_spinunlock(self, &thread->pt_flaglock);
return ESRCH;
}
/*
* "I'm not dead yet!"
* "You will be soon enough."
*/
pthread_spinunlock(self, &thread->pt_flaglock);
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_flaglock);
pthread_spinlock(self, &thread->pt_join_lock);
}
/* All ours. */
thread->pt_state = PT_STATE_DEAD;
name = thread->pt_name;
thread->pt_name = NULL;
pthread_spinunlock(self, &thread->pt_join_lock);
pthread_spinunlock(self, &thread->pt_flaglock);
if (valptr != NULL)
*valptr = thread->pt_exitval;
SDPRINTF(("(pthread_join %p) Joined %p.\n", self, thread));
/* Cleanup time. Move the dead thread from allqueue to the deadqueue */
pthread_spinlock(self, &pthread__allqueue_lock);
PTQ_REMOVE(&pthread__allqueue, thread, pt_allq);
pthread_spinunlock(self, &pthread__allqueue_lock);
pthread_spinlock(self, &pthread__deadqueue_lock);
PTQ_INSERT_HEAD(&pthread__deadqueue, thread, pt_allq);
pthread_spinunlock(self, &pthread__deadqueue_lock);
if (name != NULL)
free(name);
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;
self = pthread__self();
if (pthread__find(self, thread) != 0)
return ESRCH;
if (thread->pt_magic != PT_MAGIC)
return EINVAL;
pthread_spinlock(self, &thread->pt_flaglock);
pthread_spinlock(self, &thread->pt_join_lock);
if (thread->pt_flags & PT_FLAG_DETACHED) {
pthread_spinunlock(self, &thread->pt_join_lock);
pthread_spinunlock(self, &thread->pt_flaglock);
return EINVAL;
}
thread->pt_flags |= PT_FLAG_DETACHED;
/* Any joiners have to be punted now. */
pthread__sched_sleepers(self, &thread->pt_joiners);
pthread_spinunlock(self, &thread->pt_join_lock);
pthread_spinunlock(self, &thread->pt_flaglock);
return 0;
}
int
pthread_getname_np(pthread_t thread, char *name, size_t len)
{
pthread_t self;
self = pthread__self();
if (pthread__find(self, thread) != 0)
return ESRCH;
if (thread->pt_magic != PT_MAGIC)
return EINVAL;
pthread_spinlock(self, &thread->pt_join_lock);
if (thread->pt_name == NULL)
name[0] = '\0';
else
strlcpy(name, thread->pt_name, len);
pthread_spinunlock(self, &thread->pt_join_lock);
return 0;
}
int
pthread_setname_np(pthread_t thread, const char *name, void *arg)
{
pthread_t self = pthread_self();
char *oldname, *cp, newname[PTHREAD_MAX_NAMELEN_NP];
int namelen;
if (pthread__find(self, thread) != 0)
return ESRCH;
if (thread->pt_magic != PT_MAGIC)
return EINVAL;
namelen = snprintf(newname, sizeof(newname), name, arg);
if (namelen >= PTHREAD_MAX_NAMELEN_NP)
return EINVAL;
cp = strdup(newname);
if (cp == NULL)
return ENOMEM;
pthread_spinlock(self, &thread->pt_join_lock);
if (thread->pt_state == PT_STATE_DEAD) {
pthread_spinunlock(self, &thread->pt_join_lock);
free(cp);
return EINVAL;
}
oldname = thread->pt_name;
thread->pt_name = cp;
pthread_spinunlock(self, &thread->pt_join_lock);
if (oldname != NULL)
free(oldname);
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;
if (!(thread->pt_state == PT_STATE_RUNNING ||
thread->pt_state == PT_STATE_RUNNABLE ||
thread->pt_state == PT_STATE_BLOCKED_QUEUE))
return ESRCH;
self = pthread__self();
pthread_spinlock(self, &thread->pt_flaglock);
thread->pt_flags |= PT_FLAG_CS_PENDING;
if ((thread->pt_flags & PT_FLAG_CS_DISABLED) == 0) {
thread->pt_cancel = 1;
pthread_spinunlock(self, &thread->pt_flaglock);
pthread_spinlock(self, &thread->pt_statelock);
if (thread->pt_blockgen != thread->pt_unblockgen) {
/*
* 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; it will
* check for the cancellation if the routine
* is a cancellation point, and loop and reblock
* otherwise.
*/
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);
} else
pthread_spinunlock(self, &thread->pt_flaglock);
return 0;
}
int
pthread_setcancelstate(int state, int *oldstate)
{
pthread_t self;
int retval;
self = pthread__self();
retval = 0;
pthread_spinlock(self, &self->pt_flaglock);
if (oldstate != NULL) {
if (self->pt_flags & PT_FLAG_CS_DISABLED)
*oldstate = PTHREAD_CANCEL_DISABLE;
else
*oldstate = PTHREAD_CANCEL_ENABLE;
}
if (state == PTHREAD_CANCEL_DISABLE) {
self->pt_flags |= PT_FLAG_CS_DISABLED;
if (self->pt_cancel) {
self->pt_flags |= PT_FLAG_CS_PENDING;
self->pt_cancel = 0;
}
} else if (state == PTHREAD_CANCEL_ENABLE) {
self->pt_flags &= ~PT_FLAG_CS_DISABLED;
/*
* If a cancellation was requested while cancellation
* was disabled, note that fact for future
* cancellation tests.
*/
if (self->pt_flags & PT_FLAG_CS_PENDING) {
self->pt_cancel = 1;
/* This is not a deferred cancellation point. */
if (self->pt_flags & PT_FLAG_CS_ASYNC) {
pthread_spinunlock(self, &self->pt_flaglock);
pthread_exit(PTHREAD_CANCELED);
}
}
} else
retval = EINVAL;
pthread_spinunlock(self, &self->pt_flaglock);
return retval;
}
int
pthread_setcanceltype(int type, int *oldtype)
{
pthread_t self;
int retval;
self = pthread__self();
retval = 0;
pthread_spinlock(self, &self->pt_flaglock);
if (oldtype != NULL) {
if (self->pt_flags & PT_FLAG_CS_ASYNC)
*oldtype = PTHREAD_CANCEL_ASYNCHRONOUS;
else
*oldtype = PTHREAD_CANCEL_DEFERRED;
}
if (type == PTHREAD_CANCEL_ASYNCHRONOUS) {
self->pt_flags |= PT_FLAG_CS_ASYNC;
if (self->pt_cancel) {
pthread_spinunlock(self, &self->pt_flaglock);
pthread_exit(PTHREAD_CANCELED);
}
} else if (type == PTHREAD_CANCEL_DEFERRED)
self->pt_flags &= ~PT_FLAG_CS_ASYNC;
else
retval = EINVAL;
pthread_spinunlock(self, &self->pt_flaglock);
return retval;
}
void
pthread_testcancel()
{
pthread_t self;
self = pthread__self();
if (self->pt_cancel)
pthread_exit(PTHREAD_CANCELED);
}
/*
* POSIX requires that certain functions return an error rather than
* invoking undefined behavior even when handed completely bogus
* pthread_t values, e.g. stack garbage or (pthread_t)666. This
* utility routine searches the list of threads for the pthread_t
* value without dereferencing it.
*/
int
pthread__find(pthread_t self, pthread_t id)
{
pthread_t target;
pthread_spinlock(self, &pthread__allqueue_lock);
PTQ_FOREACH(target, &pthread__allqueue, pt_allq)
if (target == id)
break;
pthread_spinunlock(self, &pthread__allqueue_lock);
if (target == NULL)
return ESRCH;
return 0;
}
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);
}
ssize_t _sys_write(int, const void *, size_t);
void
pthread__assertfunc(char *file, int line, char *function, char *expr)
{
char buf[1024];
int len;
/*
* snprintf should not acquire any locks, or we could
* end up deadlocked if the assert caller held locks.
*/
len = snprintf(buf, 1024,
"assertion \"%s\" failed: file \"%s\", line %d%s%s%s\n",
expr, file, line,
function ? ", function \"" : "",
function ? function : "",
function ? "\"" : "");
_sys_write(STDERR_FILENO, buf, (size_t)len);
(void)kill(getpid(), SIGABRT);
_exit(1);
}
void
pthread__errorfunc(char *file, int line, char *function, char *msg)
{
char buf[1024];
size_t len;
if (pthread__diagassert == 0)
return;
/*
* snprintf should not acquire any locks, or we could
* end up deadlocked if the assert caller held locks.
*/
len = snprintf(buf, 1024,
"%s: Error detected by libpthread: %s.\n"
"Detected by file \"%s\", line %d%s%s%s.\n"
"See pthread(3) for information.\n",
getprogname(), msg, file, line,
function ? ", function \"" : "",
function ? function : "",
function ? "\"" : "");
if (pthread__diagassert & DIAGASSERT_STDERR)
_sys_write(STDERR_FILENO, buf, len);
if (pthread__diagassert & DIAGASSERT_SYSLOG)
syslog(LOG_DEBUG | LOG_USER, "%s", buf);
if (pthread__diagassert & DIAGASSERT_ABORT) {
(void)kill(getpid(), SIGABRT);
_exit(1);
}
}
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