1 /* $Id$ */

     2 

     3 /** @file thread_pthread.cpp POSIX pthread implementation of Threads. */

     4 

     5 #include "stdafx.h"

     6 #include "thread.h"

     7 #include "debug.h"

     8 #include "core/alloc_func.hpp"

     9 #include <stdlib.h>

    10 #include <pthread.h>

    11 #include <semaphore.h>

    12 #include <unistd.h>

    13 

    14 struct OTTDThread {

    15 	pthread_t thread;

    16 };

    17 

    18 OTTDThread *OTTDCreateThread(OTTDThreadFunc function, void *arg)

    19 {

    20 	OTTDThread *t = MallocT<OTTDThread>(1);

    21 

    22 	if (t == NULL) return NULL;

    23 

    24 	if (pthread_create(&t->thread, NULL, function, arg) == 0) {

    25 		return t;

    26 	} else {

    27 		free(t);

    28 		return NULL;

    29 	}

    30 }

    31 

    32 void *OTTDJoinThread(OTTDThread *t)

    33 {

    34 	void* ret;

    35 

    36 	if (t == NULL) return NULL;

    37 

    38 	pthread_join(t->thread, &ret);

    39 	free(t);

    40 	return ret;

    41 }

    42 

    43 void OTTDExitThread()

    44 {

    45 	pthread_exit(NULL);

    46 }

    47 

    48 

    49 /**

    50  * POSIX pthread version for ThreadObject.

    51  */

    52 class ThreadObject_pthread : public ThreadObject {

    53 private:

    54 	pthread_t m_thr;             ///< System thread identifier.

    55 	OTTDThreadFunc m_proc;       ///< External thread procedure.

    56 	void     *m_param;           ///< Parameter for the external thread procedure.

    57 	bool      m_attached;        ///< True if the ThreadObject was attached to an existing thread.

    58 	sem_t     m_sem_start;       ///< Here the new thread waits before it starts.

    59 	sem_t     m_sem_stop;        ///< Here the other thread can wait for this thread to end.

    60 

    61 public:

    62 	/**

    63 	 * Create a pthread and start it, calling proc(param).

    64 	 */

    65 	ThreadObject_pthread(OTTDThreadFunc proc, void *param) :

    66 		m_thr(0),

    67 		m_proc(proc),

    68 		m_param(param),

    69 		m_attached(false)

    70 	{

    71 		sem_init(&m_sem_start, 0, 0);

    72 		sem_init(&m_sem_stop, 0, 0);

    73 

    74 		pthread_create(&m_thr, NULL, &stThreadProc, this);

    75 		sem_post(&m_sem_start);

    76 	}

    77 

    78 	/**

    79 	 * Create a pthread and attach current thread to it.

    80 	 */

    81 	ThreadObject_pthread() :

    82 		m_thr(0),

    83 		m_proc(NULL),

    84 		m_param(0),

    85 		m_attached(true)

    86 	{

    87 		sem_init(&m_sem_start, 0, 0);

    88 		sem_init(&m_sem_stop, 0, 0);

    89 

    90 		m_thr = pthread_self();

    91 	}

    92 

    93 	/* virtual */ ~ThreadObject_pthread()

    94 	{

    95 		sem_destroy(&m_sem_stop);

    96 		sem_destroy(&m_sem_start);

    97 	};

    98 

    99 	/* virtual */ bool IsRunning()

   100 	{

   101 		return m_thr != 0;

   102 	}

   103 

   104 	/* virtual */ bool WaitForStop()

   105 	{

   106 		/* You can't wait on yourself */

   107 		assert(!IsCurrent());

   108 		/* If the thread is not running, waiting is over */

   109 		if (!IsRunning()) return true;

   110 

   111 		int ret = sem_wait(&m_sem_stop);

   112 		if (ret == 0) {

   113 			/* We have passed semaphore so increment it again */

   114 			sem_post(&m_sem_stop);

   115 			return true;

   116 		}

   117 		return false;

   118 	}

   119 

   120 	/* virtual */ bool IsCurrent()

   121 	{

   122 		return pthread_self() == m_thr;

   123 	}

   124 

   125 	/* virtual */ uint GetId()

   126 	{

   127 		return (uint)m_thr;

   128 	}

   129 

   130 private:

   131 	/**

   132 	 * On thread creation, this function is called, which calls the real startup

   133 	 *  function. This to get back into the correct instance again.

   134 	 */

   135 	static void *stThreadProc(void *thr)

   136 	{

   137 		return ((ThreadObject_pthread*)thr)->ThreadProc();

   138 	}

   139 

   140 	/**

   141 	 * A new thread is created, and this function is called. Call the custom

   142 	 *  function of the creator of the thread.

   143 	 */

   144 	void *ThreadProc()

   145 	{

   146 		/* The new thread stops here so the calling thread can complete pthread_create() call */

   147 		sem_wait(&m_sem_start);

   148 

   149 		/* Call the proc of the creator to continue this thread */

   150 		try {

   151 			m_proc(m_param);

   152 		} catch (...) {

   153 			DEBUG(misc, 0, "Exception in thread %u!", GetId());

   154 		}

   155 		/* The thread died, so we are no longer valid */

   156 		m_thr = 0;

   157 

   158 		/* Notify threads waiting for our completion */

   159 		sem_post(&m_sem_stop);

   160 		return NULL;

   161 	}

   162 };

   163 

   164 /* static */ ThreadObject *ThreadObject::New(OTTDThreadFunc proc, void *param)

   165 {

   166 	return new ThreadObject_pthread(proc, param);

   167 }

   168 

   169 /* static */ ThreadObject *ThreadObject::AttachCurrent()

   170 {

   171 	return new ThreadObject_pthread();

   172 }

   173 

   174 /* static */ uint ThreadObject::CurrentId()

   175 {

   176 	return (uint)pthread_self();

   177 }

   178 

   179 

   180 /**

   181  * POSIX pthread version of ThreadSemaphore.

   182  */

   183 class ThreadSemaphore_pthread : public ThreadSemaphore {

   184 private:

   185 	sem_t m_sem;

   186 

   187 public:

   188 	ThreadSemaphore_pthread()

   189 	{

   190 		sem_init(&m_sem, 0, 0);

   191 	}

   192 

   193 	/* virtual */ ~ThreadSemaphore_pthread()

   194 	{

   195 		sem_destroy(&m_sem);

   196 	}

   197 

   198 	/* virtual */ void Set()

   199 	{

   200 		int val = 0;

   201 		if (sem_getvalue(&m_sem, &val) == 0 && val == 0) sem_post(&m_sem);

   202 	}

   203 

   204 	/* virtual */ void Wait()

   205 	{

   206 		sem_wait(&m_sem);

   207 	}

   208 };

   209 

   210 /* static */ ThreadSemaphore *ThreadSemaphore::New()

   211 {

   212 	return new ThreadSemaphore_pthread();

   213 }