src/thread/pthread/SDL_systhread.c
author Sam Lantinga <slouken@libsdl.org>
Fri, 25 Mar 2011 12:54:21 -0700
changeset 5510 55519e27e5d1
parent 5509 5b1b4d820d10
child 5513 0a72c9c29099
permissions -rw-r--r--
Warn people not to run their applications as root!

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2011 Sam Lantinga

    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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/
#include "SDL_config.h"

#include <pthread.h>
#include <signal.h>
#ifdef linux
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/syscall.h>
#endif

#include "SDL_thread.h"
#include "../SDL_thread_c.h"
#include "../SDL_systhread.h"

/* List of signals to mask in the subthreads */
static const int sig_list[] = {
    SIGHUP, SIGINT, SIGQUIT, SIGPIPE, SIGALRM, SIGTERM, SIGCHLD, SIGWINCH,
    SIGVTALRM, SIGPROF, 0
};


static void *
RunThread(void *data)
{
    SDL_RunThread(data);
    pthread_exit((void *) 0);
    return ((void *) 0);        /* Prevent compiler warning */
}

int
SDL_SYS_CreateThread(SDL_Thread * thread, void *args)
{
    pthread_attr_t type;

    /* Set the thread attributes */
    if (pthread_attr_init(&type) != 0) {
        SDL_SetError("Couldn't initialize pthread attributes");
        return (-1);
    }
    pthread_attr_setdetachstate(&type, PTHREAD_CREATE_JOINABLE);

    /* Create the thread and go! */
    if (pthread_create(&thread->handle, &type, RunThread, args) != 0) {
        SDL_SetError("Not enough resources to create thread");
        return (-1);
    }

    return (0);
}

void
SDL_SYS_SetupThread(void)
{
    int i;
    sigset_t mask;

    /* Mask asynchronous signals for this thread */
    sigemptyset(&mask);
    for (i = 0; sig_list[i]; ++i) {
        sigaddset(&mask, sig_list[i]);
    }
    pthread_sigmask(SIG_BLOCK, &mask, 0);

#ifdef PTHREAD_CANCEL_ASYNCHRONOUS
    /* Allow ourselves to be asynchronously cancelled */
    {
        int oldstate;
        pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, &oldstate);
    }
#endif
}

SDL_threadID
SDL_ThreadID(void)
{
    return ((SDL_threadID) pthread_self());
}

int
SDL_SYS_SetThreadPriority(SDL_ThreadPriority priority)
{
#ifdef linux
    int value;

    if (priority == SDL_THREAD_PRIORITY_LOW) {
        value = 19;
    } else if (priority == SDL_THREAD_PRIORITY_HIGH) {
        value = -20;
    } else {
        value = 0;
    }
    if (setpriority(PRIO_PROCESS, syscall(SYS_gettid), value) < 0) {
        /* Note that this fails if you're trying to set high priority
           and you don't have root permission. BUT DON'T RUN AS ROOT!
         */
        SDL_SetError("setpriority() failed");
        return -1;
    }
    return 0;
#else
    struct sched_param sched;
    int policy;
    pthread_t thread = pthread_self();

    if (pthread_getschedparam(thread, &policy, &sched) < 0) {
        SDL_SetError("pthread_getschedparam() failed");
        return -1;
    }
    if (priority == SDL_THREAD_PRIORITY_LOW) {
        sched.sched_priority = sched_get_priority_min(policy);
    } else if (priority == SDL_THREAD_PRIORITY_HIGH) {
        sched.sched_priority = sched_get_priority_max(policy);
    } else {
        int min_priority = sched_get_priority_min(policy);
        int max_priority = sched_get_priority_max(policy);
        sched.sched_priority = (min_priority + (max_priority - min_priority) / 2);
    }
    if (pthread_setschedparam(thread, policy, &sched) < 0) {
        SDL_SetError("pthread_setschedparam() failed");
        return -1;
    }
    return 0;
#endif /* linux */
}

void
SDL_SYS_WaitThread(SDL_Thread * thread)
{
    pthread_join(thread->handle, 0);
}

/* vi: set ts=4 sw=4 expandtab: */