SDL/src/thread/pthread/SDL_systhread.c

/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2021 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/
#include "../../SDL_internal.h"

#include "SDL_system.h"
#include "SDL_hints.h"

#include <pthread.h>

#if HAVE_PTHREAD_NP_H
#include <pthread_np.h>
#endif

#include <signal.h>

#ifdef __LINUX__
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/syscall.h>
#include <unistd.h>
#include <errno.h>

#include "../../core/linux/SDL_dbus.h"
#endif /* __LINUX__ */

#if (defined(__LINUX__) || defined(__MACOSX__) || defined(__IPHONEOS__)) && defined(HAVE_DLOPEN)
#include <dlfcn.h>
#ifndef RTLD_DEFAULT
#define RTLD_DEFAULT NULL
#endif
#endif

#include "SDL_thread.h"
#include "../SDL_thread_c.h"
#include "../SDL_systhread.h"
#ifdef __ANDROID__
#include "../../core/android/SDL_android.h"
#endif

#ifdef __HAIKU__
#include <kernel/OS.h>
#endif


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

static void *
RunThread(void *data)
{
#ifdef __ANDROID__
    Android_JNI_SetupThread();
#endif
    SDL_RunThread((SDL_Thread *) data);
    return NULL;
}

#if (defined(__MACOSX__) || defined(__IPHONEOS__)) && defined(HAVE_DLOPEN)
static SDL_bool checked_setname = SDL_FALSE;
static int (*ppthread_setname_np)(const char*) = NULL;
#elif defined(__LINUX__) && defined(HAVE_DLOPEN)
static SDL_bool checked_setname = SDL_FALSE;
static int (*ppthread_setname_np)(pthread_t, const char*) = NULL;
#endif
int
SDL_SYS_CreateThread(SDL_Thread * thread)
{
    pthread_attr_t type;

    /* do this here before any threads exist, so there's no race condition. */
    #if (defined(__MACOSX__) || defined(__IPHONEOS__) || defined(__LINUX__)) && defined(HAVE_DLOPEN)
    if (!checked_setname) {
        void *fn = dlsym(RTLD_DEFAULT, "pthread_setname_np");
        #if defined(__MACOSX__) || defined(__IPHONEOS__)
        ppthread_setname_np = (int(*)(const char*)) fn;
        #elif defined(__LINUX__)
        ppthread_setname_np = (int(*)(pthread_t, const char*)) fn;
        #endif
        checked_setname = SDL_TRUE;
    }
    #endif

    /* Set the thread attributes */
    if (pthread_attr_init(&type) != 0) {
        return SDL_SetError("Couldn't initialize pthread attributes");
    }
    pthread_attr_setdetachstate(&type, PTHREAD_CREATE_JOINABLE);
    
    /* Set caller-requested stack size. Otherwise: use the system default. */
    if (thread->stacksize) {
        pthread_attr_setstacksize(&type, thread->stacksize);
    }

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

    return 0;
}

void
SDL_SYS_SetupThread(const char *name)
{
#if !defined(__NACL__)
    int i;
    sigset_t mask;
#endif /* !__NACL__ */

    if (name != NULL) {
        #if (defined(__MACOSX__) || defined(__IPHONEOS__) || defined(__LINUX__)) && defined(HAVE_DLOPEN)
        SDL_assert(checked_setname);
        if (ppthread_setname_np != NULL) {
            #if defined(__MACOSX__) || defined(__IPHONEOS__)
            ppthread_setname_np(name);
            #elif defined(__LINUX__)
            ppthread_setname_np(pthread_self(), name);
            #endif
        }
        #elif HAVE_PTHREAD_SETNAME_NP
            #if defined(__NETBSD__)
            pthread_setname_np(pthread_self(), "%s", name);
            #else
            pthread_setname_np(pthread_self(), name);
            #endif
        #elif HAVE_PTHREAD_SET_NAME_NP
            pthread_set_name_np(pthread_self(), name);
        #elif defined(__HAIKU__)
            /* The docs say the thread name can't be longer than B_OS_NAME_LENGTH. */
            char namebuf[B_OS_NAME_LENGTH];
            SDL_snprintf(namebuf, sizeof (namebuf), "%s", name);
            namebuf[sizeof (namebuf) - 1] = '\0';
            rename_thread(find_thread(NULL), namebuf);
        #endif
    }

   /* NativeClient does not yet support signals.*/
#if !defined(__NACL__)
    /* 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);
#endif /* !__NACL__ */


#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());
}

#if __LINUX__
/**
   \brief Sets the SDL priority (not nice level) for a thread, using setpriority() if appropriate, and RealtimeKit if available.
   Differs from SDL_LinuxSetThreadPriority in also taking the desired scheduler policy,
   such as SCHED_OTHER or SCHED_RR.

   \return 0 on success, or -1 on error.
 */
extern DECLSPEC int SDLCALL SDL_LinuxSetThreadPriorityAndPolicy(Sint64 threadID, int sdlPriority, int schedPolicy);
#endif

int
SDL_SYS_SetThreadPriority(SDL_ThreadPriority priority)
{
#if __NACL__ || __RISCOS__
    /* FIXME: Setting thread priority does not seem to be supported in NACL */
    return 0;
#else
    struct sched_param sched;
    int policy;
    int pri_policy;
    pthread_t thread = pthread_self();
    const char *policyhint = SDL_GetHint(SDL_HINT_THREAD_PRIORITY_POLICY);
    const SDL_bool timecritical_realtime_hint = SDL_GetHintBoolean(SDL_HINT_THREAD_FORCE_REALTIME_TIME_CRITICAL, SDL_FALSE);

    if (pthread_getschedparam(thread, &policy, &sched) != 0) {
        return SDL_SetError("pthread_getschedparam() failed");
    }

    /* Higher priority levels may require changing the pthread scheduler policy
     * for the thread.  SDL will make such changes by default but there is
     * also a hint allowing that behavior to be overridden. */
    switch (priority) {
    case SDL_THREAD_PRIORITY_LOW:
    case SDL_THREAD_PRIORITY_NORMAL:
        pri_policy = SCHED_OTHER;
        break;
    case SDL_THREAD_PRIORITY_HIGH:
    case SDL_THREAD_PRIORITY_TIME_CRITICAL:
#if defined(__MACOSX__) || defined(__IPHONEOS__) || defined(__TVOS__)
        /* Apple requires SCHED_RR for high priority threads */
        pri_policy = SCHED_RR;
        break;
#else
        pri_policy = SCHED_OTHER;
        break;
#endif
    default:
        pri_policy = policy;
        break;
    }

    if (timecritical_realtime_hint && priority == SDL_THREAD_PRIORITY_TIME_CRITICAL) {
        pri_policy = SCHED_RR;
    }

    if (policyhint) {
        if (SDL_strcmp(policyhint, "current") == 0) {
            /* Leave current thread scheduler policy unchanged */
        } else if (SDL_strcmp(policyhint, "other") == 0) {
            policy = SCHED_OTHER;
        } else if (SDL_strcmp(policyhint, "rr") == 0) {
            policy = SCHED_RR;
        } else if (SDL_strcmp(policyhint, "fifo") == 0) {
            policy = SCHED_FIFO;
        } else {
            policy = pri_policy;
        }
    } else {
        policy = pri_policy;
    }

#if __LINUX__
    {
        pid_t linuxTid = syscall(SYS_gettid);
        return SDL_LinuxSetThreadPriorityAndPolicy(linuxTid, priority, policy);
    }
#else
    if (priority == SDL_THREAD_PRIORITY_LOW) {
        sched.sched_priority = sched_get_priority_min(policy);
    } else if (priority == SDL_THREAD_PRIORITY_TIME_CRITICAL) {
        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);

#if defined(__MACOSX__) || defined(__IPHONEOS__) || defined(__TVOS__)
        if (min_priority == 15 && max_priority == 47) {
            /* Apple has a specific set of thread priorities */
            if (priority == SDL_THREAD_PRIORITY_HIGH) {
                sched.sched_priority = 45;
            } else {
                sched.sched_priority = 37;
            }
        } else
#endif /* __MACOSX__ || __IPHONEOS__ || __TVOS__ */
        {
            sched.sched_priority = (min_priority + (max_priority - min_priority) / 2);
            if (priority == SDL_THREAD_PRIORITY_HIGH) {
                sched.sched_priority += ((max_priority - min_priority) / 4);
            }
        }
    }
    if (pthread_setschedparam(thread, policy, &sched) != 0) {
        return SDL_SetError("pthread_setschedparam() failed");
    }
    return 0;
#endif /* linux */
#endif /* #if __NACL__ || __RISCOS__ */
}

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

void
SDL_SYS_DetachThread(SDL_Thread * thread)
{
    pthread_detach(thread->handle);
}

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