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/* $OpenBSD: rthread.c,v 1.9 2020/10/12 22:06:51 deraadt Exp $ */
/*
* Copyright (c) 2004,2005 Ted Unangst <tedu@openbsd.org>
* All Rights Reserved.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/*
* The infrastructure of rthreads
*/
#include <sys/types.h>
#include <sys/atomic.h>
#include <pthread.h>
#include <stdlib.h>
#include <tib.h>
#include <unistd.h>
#include "rthread.h"
#define RTHREAD_ENV_DEBUG "RTHREAD_DEBUG"
int _rthread_debug_level;
static int _threads_inited;
struct pthread _initial_thread = {
.flags_lock = _SPINLOCK_UNLOCKED,
.name = "Original thread",
};
/*
* internal support functions
*/
void
_spinlock(volatile _atomic_lock_t *lock)
{
while (_atomic_lock(lock))
sched_yield();
membar_enter_after_atomic();
}
DEF_STRONG(_spinlock);
int
_spinlocktry(volatile _atomic_lock_t *lock)
{
if (_atomic_lock(lock) == 0) {
membar_enter_after_atomic();
return 1;
}
return 0;
}
void
_spinunlock(volatile _atomic_lock_t *lock)
{
membar_exit();
*lock = _ATOMIC_LOCK_UNLOCKED;
}
DEF_STRONG(_spinunlock);
static void
_rthread_init(void)
{
pthread_t thread = &_initial_thread;
struct tib *tib;
if (_threads_inited)
return;
tib = TIB_GET();
tib->tib_thread = thread;
thread->tib = tib;
thread->donesem.lock = _SPINLOCK_UNLOCKED;
tib->tib_thread_flags = TIB_THREAD_INITIAL_STACK;
/*
* Set the debug level from an environment string.
* Bogus values are silently ignored.
*/
if (!issetugid()) {
char *envp = getenv(RTHREAD_ENV_DEBUG);
if (envp != NULL) {
char *rem;
_rthread_debug_level = (int) strtol(envp, &rem, 0);
if (*rem != '\0' || _rthread_debug_level < 0)
_rthread_debug_level = 0;
}
}
_threads_inited = 1;
}
/*
* real pthread functions
*/
pthread_t
pthread_self(void)
{
if (__predict_false(!_threads_inited))
_rthread_init();
return TIB_GET()->tib_thread;
}
DEF_STRONG(pthread_self);
void
pthread_exit(void *retval)
{
struct rthread_cleanup_fn *clfn;
struct tib *tib;
pthread_t thread = pthread_self();
tib = thread->tib;
if (tib->tib_cantcancel & CANCEL_DYING) {
/*
* Called pthread_exit() from destructor or cancelation
* handler: blow up. XXX write something to stderr?
*/
abort();
//_exit(42);
}
tib->tib_cantcancel |= CANCEL_DYING;
thread->retval = retval;
for (clfn = thread->cleanup_fns; clfn; ) {
struct rthread_cleanup_fn *oclfn = clfn;
clfn = clfn->next;
oclfn->fn(oclfn->arg);
free(oclfn);
}
_thread_finalize();
_rthread_tls_destructors(thread);
if (_thread_cb.tc_thread_release != NULL)
_thread_cb.tc_thread_release(thread);
__threxit(&tib->tib_tid);
for(;;);
}
DEF_STRONG(pthread_exit);
int
pthread_equal(pthread_t t1, pthread_t t2)
{
return (t1 == t2);
}
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