port/threads/pthread.c

	pthread.c revision 7257d1b4d25bfac0c802847390e98a464fd787ac
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include "lint.h"
#include "thr_uberdata.h"

/*
 * pthread_once related data
 * This structure is exported as pthread_once_t in pthread.h.
 * We export only the size of this structure. so check
 * pthread_once_t in pthread.h before making a change here.
 */
typedef struct  __once {
    mutex_t mlock;
    union {
        uint32_t    pad32_flag[2];
        uint64_t    pad64_flag;
    } oflag;
} __once_t;

#define once_flag   oflag.pad32_flag[1]

static int
_thr_setparam(pthread_t tid, int policy, int prio)
{
    ulwp_t *ulwp;
    id_t cid;
    int error = 0;

    if ((ulwp = find_lwp(tid)) == NULL) {
        error = ESRCH;
    } else {
        if (policy == ulwp->ul_policy &&
            (policy == SCHED_FIFO || policy == SCHED_RR) &&
            ulwp->ul_epri != 0) {
            /*
             * Don't change the ceiling priority,
             * just the base priority.
             */
            if (prio > ulwp->ul_epri)
                error = EPERM;
            else
                ulwp->ul_pri = prio;
        } else if ((cid = setparam(P_LWPID, tid, policy, prio)) == -1) {
            error = errno;
        } else {
            if (policy == SCHED_FIFO || policy == SCHED_RR)
                ulwp->ul_rtclassid = cid;
            ulwp->ul_cid = cid;
            ulwp->ul_pri = prio;
            membar_producer();
            ulwp->ul_policy = policy;
        }
        ulwp_unlock(ulwp, curthread->ul_uberdata);
    }
    return (error);
}

/*
 * pthread_create: creates a thread in the current process.
 * calls common _thrp_create() after copying the attributes.
 */
#pragma weak _pthread_create = pthread_create
int
pthread_create(pthread_t *thread, const pthread_attr_t *attr,
    void * (*start_routine)(void *), void *arg)
{
    ulwp_t      *self = curthread;
    const thrattr_t *ap = attr? attr->__pthread_attrp : def_thrattr();
    const pcclass_t *pccp;
    long        flag;
    pthread_t   tid;
    int     error;

    update_sched(self);

    if (ap == NULL)
        return (EINVAL);

    /* validate explicit scheduling attributes */
    if (ap->inherit == PTHREAD_EXPLICIT_SCHED &&
        (ap->policy == SCHED_SYS ||
        (pccp = get_info_by_policy(ap->policy)) == NULL ||
        ap->prio < pccp->pcc_primin || ap->prio > pccp->pcc_primax))
        return (EINVAL);

    flag = ap->scope | ap->detachstate | ap->daemonstate | THR_SUSPENDED;
    error = _thrp_create(ap->stkaddr, ap->stksize, start_routine, arg,
        flag, &tid, ap->guardsize);
    if (error == 0) {
        if (ap->inherit == PTHREAD_EXPLICIT_SCHED &&
            (ap->policy != self->ul_policy ||
            ap->prio != (self->ul_epri? self->ul_epri : self->ul_pri)))
            /*
             * The SUSv3 specification requires pthread_create()
             * to fail with EPERM if it cannot set the scheduling
             * policy and parameters on the new thread.
             */
            error = _thr_setparam(tid, ap->policy, ap->prio);
        if (error) {
            /*
             * We couldn't determine this error before
             * actually creating the thread.  To recover,
             * mark the thread detached and cancel it.
             * It is as though it was never created.
             */
            ulwp_t *ulwp = find_lwp(tid);
            if (ulwp->ul_detached == 0) {
                ulwp->ul_detached = 1;
                ulwp->ul_usropts |= THR_DETACHED;
                (void) __lwp_detach(tid);
            }
            ulwp->ul_cancel_pending = 2; /* cancelled on creation */
            ulwp->ul_cancel_disabled = 0;
            ulwp_unlock(ulwp, self->ul_uberdata);
        } else if (thread) {
            *thread = tid;
        }
        (void) thr_continue(tid);
    }

    /* posix version expects EAGAIN for lack of memory */
    if (error == ENOMEM)
        error = EAGAIN;
    return (error);
}

/*
 * pthread_once: calls given function only once.
 * it synchronizes via mutex in pthread_once_t structure
 */
int
pthread_once(pthread_once_t *once_control, void (*init_routine)(void))
{
    __once_t *once = (__once_t *)once_control;

    if (once == NULL || init_routine == NULL)
        return (EINVAL);

    if (once->once_flag == PTHREAD_ONCE_NOTDONE) {
        (void) mutex_lock(&once->mlock);
        if (once->once_flag == PTHREAD_ONCE_NOTDONE) {
            pthread_cleanup_push(mutex_unlock, &once->mlock);
            (*init_routine)();
            pthread_cleanup_pop(0);
            membar_producer();
            once->once_flag = PTHREAD_ONCE_DONE;
        }
        (void) mutex_unlock(&once->mlock);
    }
    membar_consumer();

    return (0);
}

/*
 * pthread_equal: equates two thread ids.
 */
int
pthread_equal(pthread_t t1, pthread_t t2)
{
    return (t1 == t2);
}

/*
 * pthread_getschedparam: get the thread's sched parameters.
 */
#pragma weak _pthread_getschedparam = pthread_getschedparam
int
pthread_getschedparam(pthread_t tid, int *policy, struct sched_param *param)
{
    ulwp_t *ulwp;
    id_t cid;
    int error = 0;

    if ((ulwp = find_lwp(tid)) == NULL) {
        error = ESRCH;
    } else {
        cid = getparam(P_LWPID, ulwp->ul_lwpid, policy, param);
        if (cid == -1) {
            error = errno;
        } else if (*policy == ulwp->ul_policy && cid == ulwp->ul_cid &&
            (*policy == SCHED_FIFO || *policy == SCHED_RR)) {
            /*
             * Return the defined priority, not the effective
             * priority from priority ceiling mutexes.
             */
            param->sched_priority = ulwp->ul_pri;
        } else {
            if (*policy == SCHED_FIFO || *policy == SCHED_RR)
                ulwp->ul_rtclassid = cid;
            ulwp->ul_cid = cid;
            ulwp->ul_pri = param->sched_priority;
            membar_producer();
            ulwp->ul_policy = *policy;
        }
        ulwp_unlock(ulwp, curthread->ul_uberdata);
    }

    return (error);
}

#pragma weak _thr_getprio = thr_getprio
int
thr_getprio(thread_t tid, int *priority)
{
    struct sched_param param;
    int policy;
    int error;

    if ((error = pthread_getschedparam(tid, &policy, &param)) == 0)
        *priority = param.sched_priority;
    return (error);
}

/*
 * pthread_setschedparam: sets the sched parameters for a thread.
 */
int
pthread_setschedparam(pthread_t tid,
    int policy, const struct sched_param *param)
{
    return (_thr_setparam(tid, policy, param->sched_priority));
}

#pragma weak pthread_setschedprio = thr_setprio
int
thr_setprio(thread_t tid, int prio)
{
    struct sched_param param;
    int policy;
    int error;

    /*
     * pthread_getschedparam() has the side-effect of setting
     * the target thread's ul_policy, ul_pri and ul_cid correctly.
     */
    if ((error = pthread_getschedparam(tid, &policy, &param)) != 0)
        return (error);
    if (param.sched_priority == prio)   /* no change */
        return (0);
    return (_thr_setparam(tid, policy, prio));
}