pth_lib.c

Linux下的中文输入法

/*
**  GNU Pth - The GNU Portable Threads
**  Copyright (c) 1999-2004 Ralf S. Engelschall <[e-mail]>
**
**  This file is part of GNU Pth, a non-preemptive thread scheduling
**  library which can be found at http://www.gnu.org/software/pth/.
**
**  This library is free software; you can redistribute it and/or
**  modify it under the terms of the GNU Lesser General Public
**  License as published by the Free Software Foundation; either
**  version 2.1 of the License, or (at your option) any later version.
**
**  This library is distributed in the hope that it will be useful,
**  but WITHOUT ANY WARRANTY; without even the implied warranty of
**  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
**  Lesser General Public License for more details.
**
**  You should have received a copy of the GNU Lesser General Public
**  License along with this library; if not, write to the Free Software
**  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
**  USA, or contact Ralf S. Engelschall <[e-mail]>.
**
**  pth_lib.c: Pth main library code
*/
                             /* ``It took me fifteen years to discover
                                  I had no talent for programming, but
                                  I couldn't give it up because by that
                                  time I was too famous.''
                                            -- Unknown                */
#include "pth_p.h"

/* return the hexadecimal Pth library version number */
long pth_version(void)
{
    return PTH_VERSION;
}

/* implicit initialization support */
intern int pth_initialized = FALSE;
#if cpp
#define pth_implicit_init() \
    if (!pth_initialized) \
        pth_init();
#endif

#ifdef PTH_EX
/* exception handling callback functions */
static ex_ctx_t *pth_ex_ctx(void)
{
    return &(pth_current->ex_ctx);
}
static void pth_ex_terminate(ex_t *ex)
{
    pth_exit(ex->ex_value);
}
#endif

/* initialize the package */
int pth_init(void)
{
    pth_attr_t t_attr;

    /* support for implicit initialization calls
       and to prevent multiple explict initialization, too */
    if (pth_initialized)
        return pth_error(FALSE, EPERM);
    else
        pth_initialized = TRUE;

    pth_debug1("pth_init: enter");

    /* initialize syscall wrapping */
    pth_syscall_init();

    /* initialize the scheduler */
    if (!pth_scheduler_init()) {
        pth_shield { pth_syscall_kill(); }
        return pth_error(FALSE, EAGAIN);
    }

#ifdef PTH_EX
    /* optional support for exceptional handling */
    __ex_ctx       = pth_ex_ctx;
    __ex_terminate = pth_ex_terminate;
#endif

    /* spawn the scheduler thread */
    t_attr = pth_attr_new();
    pth_attr_set(t_attr, PTH_ATTR_PRIO,         PTH_PRIO_MAX);
    pth_attr_set(t_attr, PTH_ATTR_NAME,         "**SCHEDULER**");
    pth_attr_set(t_attr, PTH_ATTR_JOINABLE,     FALSE);
    pth_attr_set(t_attr, PTH_ATTR_CANCEL_STATE, PTH_CANCEL_DISABLE);
    pth_attr_set(t_attr, PTH_ATTR_STACK_SIZE,   64*1024);
    pth_attr_set(t_attr, PTH_ATTR_STACK_ADDR,   NULL);
    pth_sched = pth_spawn(t_attr, pth_scheduler, NULL);
    if (pth_sched == NULL) {
        pth_shield {
            pth_attr_destroy(t_attr);
            pth_scheduler_kill();
            pth_syscall_kill();
        }
        return FALSE;
    }

    /* spawn a thread for the main program */
    pth_attr_set(t_attr, PTH_ATTR_PRIO,         PTH_PRIO_STD);
    pth_attr_set(t_attr, PTH_ATTR_NAME,         "main");
    pth_attr_set(t_attr, PTH_ATTR_JOINABLE,     TRUE);
    pth_attr_set(t_attr, PTH_ATTR_CANCEL_STATE, PTH_CANCEL_ENABLE|PTH_CANCEL_DEFERRED);
    pth_attr_set(t_attr, PTH_ATTR_STACK_SIZE,   0 /* special */);
    pth_attr_set(t_attr, PTH_ATTR_STACK_ADDR,   NULL);
    pth_main = pth_spawn(t_attr, (void *(*)(void *))(-1), NULL);
    if (pth_main == NULL) {
        pth_shield {
            pth_attr_destroy(t_attr);
            pth_scheduler_kill();
            pth_syscall_kill();
        }
        return FALSE;
    }
    pth_attr_destroy(t_attr);

    /*
     * The first time we've to manually switch into the scheduler to start
     * threading. Because at this time the only non-scheduler thread is the
     * "main thread" we will come back immediately. We've to also initialize
     * the pth_current variable here to allow the pth_spawn_trampoline
     * function to find the scheduler.
     */
    pth_current = pth_sched;
    pth_mctx_switch(&pth_main->mctx, &pth_sched->mctx);

    /* came back, so let's go home... */
    pth_debug1("pth_init: leave");
    return TRUE;
}

/* kill the package internals */
int pth_kill(void)
{
    if (pth_current != pth_main)
        return pth_error(FALSE, EPERM);
    pth_debug1("pth_kill: enter");
    pth_thread_cleanup(pth_main);
    pth_scheduler_kill();
    pth_initialized = FALSE;
    pth_tcb_free(pth_sched);
    pth_tcb_free(pth_main);
    pth_syscall_kill();
#ifdef PTH_EX
    __ex_ctx       = __ex_ctx_default;
    __ex_terminate = __ex_terminate_default;
#endif
    pth_debug1("pth_kill: leave");
    return TRUE;
}

/* scheduler control/query */
long pth_ctrl(unsigned long query, ...)
{
    long rc;
    va_list ap;

    rc = 0;
    va_start(ap, query);
    if (query & PTH_CTRL_GETTHREADS) {
        if (query & PTH_CTRL_GETTHREADS_NEW)
            rc += pth_pqueue_elements(&pth_NQ);
        if (query & PTH_CTRL_GETTHREADS_READY)
            rc += pth_pqueue_elements(&pth_RQ);
        if (query & PTH_CTRL_GETTHREADS_RUNNING)
            rc += 1; /* pth_current only */
        if (query & PTH_CTRL_GETTHREADS_WAITING)
            rc += pth_pqueue_elements(&pth_WQ);
        if (query & PTH_CTRL_GETTHREADS_SUSPENDED)
            rc += pth_pqueue_elements(&pth_SQ);
        if (query & PTH_CTRL_GETTHREADS_DEAD)
            rc += pth_pqueue_elements(&pth_DQ);
    }
    else if (query & PTH_CTRL_GETAVLOAD) {
        float *pload = va_arg(ap, float *);
        *pload = pth_loadval;
    }
    else if (query & PTH_CTRL_GETPRIO) {
        pth_t t = va_arg(ap, pth_t);
        rc = t->prio;
    }
    else if (query & PTH_CTRL_GETNAME) {
        pth_t t = va_arg(ap, pth_t);
        rc = (long)t->name;
    }
    else if (query & PTH_CTRL_DUMPSTATE) {
        FILE *fp = va_arg(ap, FILE *);
        pth_dumpstate(fp);
    }
    else if (query & PTH_CTRL_FAVOURNEW) {
        int favournew = va_arg(ap, int);
        pth_favournew = (favournew ? 1 : 0);
    }
    else
        rc = -1;
    va_end(ap);
    if (rc == -1)
        return pth_error(-1, EINVAL);
    return rc;
}

/* create a new thread of execution by spawning a cooperative thread */
static void pth_spawn_trampoline(void)
{
    void *data;

    /* just jump into the start routine */
    data = (*pth_current->start_func)(pth_current->start_arg);

    /* and do an implicit exit of the thread with the result value */
    pth_exit(data);

    /* NOTREACHED */
    abort();
}
pth_t pth_spawn(pth_attr_t attr, void *(*func)(void *), void *arg)
{
    pth_t t;
    unsigned int stacksize;
    void *stackaddr;
    pth_time_t ts;

    pth_debug1("pth_spawn: enter");

    /* consistency */
    if (func == NULL)
        return pth_error((pth_t)NULL, EINVAL);

    /* support the special case of main() */
    if (func == (void *(*)(void *))(-1))
        func = NULL;

    /* allocate a new thread control block */
    stacksize = (attr == PTH_ATTR_DEFAULT ? 64*1024 : attr->a_stacksize);
    stackaddr = (attr == PTH_ATTR_DEFAULT ? NULL    : attr->a_stackaddr);
    if ((t = pth_tcb_alloc(stacksize, stackaddr)) == NULL)
        return pth_error((pth_t)NULL, errno);

    /* configure remaining attributes */
    if (attr != PTH_ATTR_DEFAULT) {
        /* overtake fields from the attribute structure */
        t->prio        = attr->a_prio;
        t->joinable    = attr->a_joinable;
        t->cancelstate = attr->a_cancelstate;
        t->dispatches  = attr->a_dispatches;
        pth_util_cpystrn(t->name, attr->a_name, PTH_TCB_NAMELEN);
    }
    else if (pth_current != NULL) {
        /* overtake some fields from the parent thread */
        t->prio        = pth_current->prio;
        t->joinable    = pth_current->joinable;
        t->cancelstate = pth_current->cancelstate;
        t->dispatches  = 0;
        pth_snprintf(t->name, PTH_TCB_NAMELEN, "%s.child@%d=0x%lx",
                     pth_current->name, (unsigned int)time(NULL),
                     (unsigned long)pth_current);
    }
    else {
        /* defaults */
        t->prio        = PTH_PRIO_STD;
        t->joinable    = TRUE;
        t->cancelstate = PTH_CANCEL_DEFAULT;
        t->dispatches  = 0;
        pth_snprintf(t->name, PTH_TCB_NAMELEN,
                     "user/%x", (unsigned int)time(NULL));
    }

    /* initialize the time points and ranges */
    pth_time_set(&ts, PTH_TIME_NOW);
    pth_time_set(&t->spawned, &ts);
    pth_time_set(&t->lastran, &ts);
    pth_time_set(&t->running, PTH_TIME_ZERO);

    /* initialize events */
    t->events = NULL;

    /* clear raised signals */
    sigemptyset(&t->sigpending);
    t->sigpendcnt = 0;

    /* remember the start routine and arguments for our trampoline */
    t->start_func = func;
    t->start_arg  = arg;

    /* initialize join argument */
    t->join_arg = NULL;

    /* initialize thread specific storage */
    t->data_value = NULL;
    t->data_count = 0;

    /* initialize cancellation stuff */
    t->cancelreq   = FALSE;
    t->cleanups    = NULL;

    /* initialize mutex stuff */
    pth_ring_init(&t->mutexring);

#ifdef PTH_EX
    /* initialize exception handling context */
    EX_CTX_INITIALIZE(&t->ex_ctx);
#endif

    /* initialize the machine context of this new thread */
    if (t->stacksize > 0) { /* the "main thread" (indicated by == 0) is special! */
        if (!pth_mctx_set(&t->mctx, pth_spawn_trampoline,
                          t->stack, ((char *)t->stack+t->stacksize))) {
            pth_shield { pth_tcb_free(t); }
            return pth_error((pth_t)NULL, errno);