src/thread/pthread/SDL_systhread.c

/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2018 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 <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__)
#include <dlfcn.h>
#ifndef RTLD_DEFAULT
#define RTLD_DEFAULT NULL
#endif
#endif

#include "SDL_log.h"
#include "SDL_platform.h"
#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

#include "SDL_assert.h"

#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(data);
    return NULL;
}

#if defined(__MACOSX__) || defined(__IPHONEOS__)
static SDL_bool checked_setname = SDL_FALSE;
static int (*ppthread_setname_np)(const char*) = NULL;
#elif defined(__LINUX__)
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, void *args)
{
    pthread_attr_t type;

    /* do this here before any threads exist, so there's no race condition. */
    #if defined(__MACOSX__) || defined(__IPHONEOS__) || defined(__LINUX__)
    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, (size_t) thread->stacksize);
    }

    /* Create the thread and go! */
    if (pthread_create(&thread->handle, &type, RunThread, args) != 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__)
        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());
}

/* d-bus queries to org.freedesktop.RealtimeKit1. */
#if SDL_USE_LIBDBUS

#define RTKIT_DBUS_NODE "org.freedesktop.RealtimeKit1"
#define RTKIT_DBUS_PATH "/org/freedesktop/RealtimeKit1"
#define RTKIT_DBUS_INTERFACE "org.freedesktop.RealtimeKit1"

static pthread_once_t rtkit_initialize_once = PTHREAD_ONCE_INIT;
static Sint32 rtkit_min_nice_level = -20;

static void
rtkit_initialize()
{
    SDL_DBusContext *dbus = SDL_DBus_GetContext();

    /* Try getting minimum nice level: this is often greater than PRIO_MIN (-20). */
    if (!dbus || !SDL_DBus_QueryPropertyOnConnection(dbus->system_conn, RTKIT_DBUS_NODE, RTKIT_DBUS_PATH, RTKIT_DBUS_INTERFACE, "MinNiceLevel",
                                            DBUS_TYPE_INT32, &rtkit_min_nice_level)) {
        rtkit_min_nice_level = -20;
    }
}

static SDL_bool
rtkit_setpriority(pid_t thread, int nice_level)
{
    Uint64 ui64 = (Uint64)thread;
    Sint32 si32 = (Sint32)nice_level;
    SDL_DBusContext *dbus = SDL_DBus_GetContext();

    pthread_once(&rtkit_initialize_once, rtkit_initialize);

    if (si32 < rtkit_min_nice_level)
        si32 = rtkit_min_nice_level;

    if (!dbus || !SDL_DBus_CallMethodOnConnection(dbus->system_conn,
            RTKIT_DBUS_NODE, RTKIT_DBUS_PATH, RTKIT_DBUS_INTERFACE, "MakeThreadHighPriority",
            DBUS_TYPE_UINT64, &ui64, DBUS_TYPE_INT32, &si32, DBUS_TYPE_INVALID,
            DBUS_TYPE_INVALID)) {
        return SDL_FALSE;
    }
    return SDL_TRUE;
}

#else

static SDL_bool
rtkit_setpriority(pid_t thread, int nice_level)
{
    return SDL_FALSE;
}

#endif /* !SDL_USE_LIBDBUS */

#if __LINUX__
int
SDL_LinuxSetThreadPriority(Sint64 threadID, int priority)
{
    if (setpriority(PRIO_PROCESS, (id_t)threadID, priority) < 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!

           You can grant the ability to increase thread priority by
           running the following command on your application binary:
               sudo setcap 'cap_sys_nice=eip' <application>

           Let's try setting priority with RealtimeKit...

           README and sample code at:
             http://git.0pointer.net/rtkit.git
         */
        if (rtkit_setpriority((pid_t)threadID, priority) == SDL_FALSE) {
            return SDL_SetError("setpriority() failed");
        }
    }
    return 0;
}
#endif /* __LINUX__ */

int
SDL_SYS_SetThreadPriority(SDL_ThreadPriority priority)
{
#if __NACL__ 
    /* FIXME: Setting thread priority does not seem to be supported in NACL */
    return 0;
#elif __LINUX__
    int value;
    pid_t thread = syscall(SYS_gettid);

    if (priority == SDL_THREAD_PRIORITY_LOW) {
        value = 19;
    } else if (priority == SDL_THREAD_PRIORITY_HIGH) {
        value = -10;
    } else if (priority == SDL_THREAD_PRIORITY_TIME_CRITICAL) {
        value = -20;
    } else {
        value = 0;
    }
    return SDL_LinuxSetThreadPriority(thread, value);
#else
    struct sched_param sched;
    int policy;
    pthread_t thread = pthread_self();

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

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

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

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