/* $Id$
 * $URL$
 *
 * thread handling (mutex, shmem, ...)
 *
 * Copyright (C) 2004 Michael Reinelt <michael@reinelt.co.at>
 * Copyright (C) 2004 The LCD4Linux Team <lcd4linux-devel@users.sourceforge.net>
 *
 * parts of this code are based on the old XWindow driver which is
 * Copyright (C) 2000 Herbert Rosmanith <herp@wildsau.idv.uni-linz.ac.at>
 *
 * This file is part of LCD4Linux.
 *
 * LCD4Linux is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * LCD4Linux 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */

/* 
 * exported functions:
 * 
 * int  mutex_create  (void);
 *   creates a mutex and treturns its ID
 * 
 * void mutex_lock    (int semid);
 *   try to lock a mutex
 *
 * void mutex_unlock  (int semid);
 *   unlock a mutex
 *
 * void mutex_destroy (int semid);
 *   release a mutex
 *
 *
 * int shm_create    (void **buffer, int size);
 *   create shared memory segment
 *
 * void shm_destroy   (int shmid, void *buffer) ;
 *   release shared memory segment
 *
 * int thread_create (char *name, void (*thread)(void *data), void *data);
 *   create a new thread
 *
 */


#include "config.h"

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#include <sys/shm.h>

#include "debug.h"
#include "thread.h"


#ifdef WITH_DMALLOC
#include <dmalloc.h>
#endif


int thread_argc;
char **thread_argv;


/* glibc 2.1 requires defining semun ourselves */
#ifdef _SEM_SEMUN_UNDEFINED
union semun {
    int val;
    struct semid_ds *buf;
    unsigned short int *array;
    struct seminfo *__buf;
};
#endif


int mutex_create(void)
{
    int semid;
    union semun semun;

    semid = semget(IPC_PRIVATE, 1, 0);
    if (semid == -1) {
	error("fatal error: semget() failed: %s", strerror(errno));
	return -1;
    }
    semun.val = 1;
    semctl(semid, 0, SETVAL, semun);

    return semid;
}


void mutex_lock(const int semid)
{
    struct sembuf sembuf;
    sembuf.sem_num = 0;
    sembuf.sem_op = -1;
    sembuf.sem_flg = 0;
    semop(semid, &sembuf, 1);
}


void mutex_unlock(const int semid)
{
    struct sembuf sembuf;
    sembuf.sem_num = 0;
    sembuf.sem_op = 1;
    sembuf.sem_flg = 0;
    semop(semid, &sembuf, 1);
}


void mutex_destroy(const int semid)
{
    union semun arg;
    semctl(semid, 0, IPC_RMID, arg);
}


int shm_create(void **buffer, const int size)
{
    int shmid;

    shmid = shmget(IPC_PRIVATE, size, SHM_R | SHM_W);
    if (shmid == -1) {
	error("fatal error: shmget() failed: %s", strerror(errno));
	return -1;
    }

    *buffer = shmat(shmid, NULL, 0);
    if (*buffer == NULL) {
	error("fatal error: shmat() failed: %s", strerror(errno));
	return -1;
    }

    return shmid;
}


void shm_destroy(const int shmid, const void *buffer)
{
    shmdt(buffer);
    shmctl(shmid, IPC_RMID, NULL);
}


int thread_create(const char *name, void (*thread) (void *data), void *data)
{
    pid_t pid, ppid;

    ppid = getpid();

    switch (pid = fork()) {
    case -1:
	error("fatal error: fork(%s) failed: %s", name, strerror(errno));
	return -1;
    case 0:
	info("thread %s starting...", name);
	if (thread_argc > 0) {
	    strncpy(thread_argv[0], name, strlen(thread_argv[0]));
	}
	thread(data);
	info("thread %s ended.", name);
	exit(0);
    default:
	info("forked process %d for thread %s", pid, name);
    }

    return pid;
}


int thread_destroy(const int pid)
{
    return kill(pid, SIGKILL);
}
/td><td>reinelt</td><td>10</td><td><span class='deletions'>-335</span>/<span class='insertions'>+719</span></td></tr>
<tr><td><span title='2004-01-14 11:33:00 +0000'>2004-01-14</span></td><td><a href='/lcd4linux.git/commit/widget_text.c?id=504656e9484752c9c0596f153f27089c1961f501&amp;follow=1'>[lcd4linux @ 2004-01-14 11:33:00 by reinelt]</a></td><td>reinelt</td><td>15</td><td><span class='deletions'>-160</span>/<span class='insertions'>+607</span></td></tr>
<tr><td><span title='2004-01-13 10:03:01 +0000'>2004-01-13</span></td><td><a href='/lcd4linux.git/commit/plugin_sample.c?id=90a08f4f1082f25ab999d8a331dcbea512778a47&amp;follow=1'>[lcd4linux @ 2004-01-13 10:03:01 by reinelt]</a></td><td>reinelt</td><td>8</td><td><span class='deletions'>-23</span>/<span class='insertions'>+458</span></td></tr>
<tr><td><span title='2004-01-13 08:18:20 +0000'>2004-01-13</span></td><td><a href='/lcd4linux.git/commit/widget_text.c?id=3cac7824479e0eef3b0bc6e33e5b4d157119a646&amp;follow=1'>[lcd4linux @ 2004-01-13 08:18:07 by reinelt]</a></td><td>reinelt</td><td>12</td><td><span class='deletions'>-154</span>/<span class='insertions'>+469</span></td></tr>
<tr><td><span title='2004-01-12 03:51:01 +0000'>2004-01-12</span></td><td><a href='/lcd4linux.git/commit/lcd4linux.c?id=14bc006adad8578e31e557d7ffb57971284a0846&amp;follow=1'>[lcd4linux @ 2004-01-12 03:51:01 by reinelt]</a></td><td>reinelt</td><td>5</td><td><span class='deletions'>-15</span>/<span class='insertions'>+44</span></td></tr>
<tr><td><span title='2004-01-11 18:26:02 +0000'>2004-01-11</span></td><td><a href='/lcd4linux.git/commit/widget_text.c?id=bbe7f194ee035c6cafdc5102092b7b422541aeab&amp;follow=1'>[lcd4linux @ 2004-01-11 18:26:02 by reinelt]</a></td><td>reinelt</td><td>10</td><td><span class='deletions'>-79</span>/<span class='insertions'>+158</span></td></tr>
<tr><td><span title='2004-01-11 09:26:15 +0000'>2004-01-11</span></td><td><a href='/lcd4linux.git/commit/widget.c?id=e2854bdb20aa686e18df912e133b790ae39ad44d&amp;follow=1'>[lcd4linux @ 2004-01-11 09:26:15 by reinelt]</a></td><td>reinelt</td><td>4</td><td><span class='deletions'>-19</span>/<span class='insertions'>+67</span></td></tr>
<tr><td><span title='2004-01-10 20:22:33 +0000'>2004-01-10</span></td><td><a href='/lcd4linux.git/commit/widget_text.c?id=a390d8386961109a8e182897753080538dce8625&amp;follow=1'>[lcd4linux @ 2004-01-10 20:22:33 by reinelt]</a></td><td>reinelt</td><td>13</td><td><span class='deletions'>-210</span>/<span class='insertions'>+554</span></td></tr>
<tr><td><span title='2004-01-10 17:45:26 +0000'>2004-01-10</span></td><td><a href='/lcd4linux.git/commit/plugin.c?id=76ffcfa4c6fb4cf45126bfd97c3ab0affe1e8e0d&amp;follow=1'>[lcd4linux @ 2004-01-10 17:45:26 by reinelt]</a></td><td>reinelt</td><td>2</td><td><span class='deletions'>-5</span>/<span class='insertions'>+15</span></td></tr>
<tr><td><span title='2004-01-10 17:36:56 +0000'>2004-01-10</span></td><td><a href='/lcd4linux.git/commit/plugin_i2c_sensors.c?id=390e66bc2d925669451ece6ce01091792da46634&amp;follow=1'>[lcd4linux @ 2004-01-10 17:36:56 by reinelt]</a></td><td>reinelt</td><td>4</td><td><span class='deletions'>-10</span>/<span class='insertions'>+207</span></td></tr>
<tr><td><span title='2004-01-10 17:34:40 +0000'>2004-01-10</span></td><td><a href='/lcd4linux.git/commit/widget.h?id=cb95898b90081079571dfbff493f9f8611637590&amp;follow=1'>[lcd4linux @ 2004-01-10 17:34:40 by reinelt]</a></td><td>reinelt</td><td>3</td><td><span class='deletions'>-176</span>/<span class='insertions'>+138</span></td></tr>
<tr><td><span title='2004-01-10 10:20:22 +0000'>2004-01-10</span></td><td><a href='/lcd4linux.git/commit/drv_MatrixOrbital.c?id=f223eb72233c076b781c2db7b99af394442a64e6&amp;follow=1'>[lcd4linux @ 2004-01-10 10:20:22 by reinelt]</a></td><td>reinelt</td><td>2</td><td><span class='deletions'>-14</span>/<span class='insertions'>+605</span></td></tr>
<tr><td><span title='2004-01-09 17:03:07 +0000'>2004-01-09</span></td><td><a href='/lcd4linux.git/commit/lcd4linux.c?id=22f3f6af66d2feea50512544df4cf32a039e559b&amp;follow=1'>[lcd4linux @ 2004-01-09 17:03:06 by reinelt]</a></td><td>reinelt</td><td>10</td><td><span class='deletions'>-51</span>/<span class='insertions'>+420</span></td></tr>
<tr><td><span title='2004-01-09 04:16:06 +0000'>2004-01-09</span></td><td><a href='/lcd4linux.git/commit/wifi.c?id=9dc6ff97fe8e9c911dfee409114fc5428adf858a&amp;follow=1'>[lcd4linux @ 2004-01-09 04:16:06 by reinelt]</a></td><td>reinelt</td><td>28</td><td><span class='deletions'>-193</span>/<span class='insertions'>+332</span></td></tr>
<tr><td><span title='2004-01-08 06:00:28 +0000'>2004-01-08</span></td><td><a href='/lcd4linux.git/commit/cfg.c?id=1cf54b00c151235704b41d192650a8e75c4ac905&amp;follow=1'>[lcd4linux @ 2004-01-08 06:00:28 by reinelt]</a></td><td>reinelt</td><td>1</td><td><span class='deletions'>-8</span>/<span class='insertions'>+14</span></td></tr>
<tr><td><span title='2004-01-08 05:28:12 +0000'>2004-01-08</span></td><td><a href='/lcd4linux.git/commit/lcd4linux.c?id=526f730eeb1a3c2d8ca73fa25f5bec4b39dd4248&amp;follow=1'>[lcd4linux @ 2004-01-08 05:28:12 by reinelt]</a></td><td>reinelt</td><td>3</td><td><span class='deletions'>-42</span>/<span class='insertions'>+198</span></td></tr>
<tr><td><span title='2004-01-07 10:15:41 +0000'>2004-01-07</span></td><td><a href='/lcd4linux.git/commit/libtool?id=cb467898be6270f34892aab862db49cc3bb169cb&amp;follow=1'>[lcd4linux @ 2004-01-07 10:15:41 by reinelt]</a></td><td>reinelt</td><td>4</td><td><span class='deletions'>-184</span>/<span class='insertions'>+436</span></td></tr>
<tr><td><span title='2004-01-06 23:01:37 +0000'>2004-01-06</span></td><td><a href='/lcd4linux.git/commit/evaluator.c?id=654ac10fea60f352a7f79955f93ea8da75517638&amp;follow=1'>[lcd4linux @ 2004-01-06 23:01:37 by reinelt]</a></td><td>reinelt</td><td>3</td><td><span class='deletions'>-4</span>/<span class='insertions'>+7</span></td></tr>
<tr><td><span title='2004-01-06 22:33:14 +0000'>2004-01-06</span></td><td><a href='/lcd4linux.git/commit/wifi.h?id=cb237ec8bae76a6f621fc0ec704e87f9163274cd&amp;follow=1'>[lcd4linux @ 2004-01-06 22:33:13 by reinelt]</a></td><td>reinelt</td><td>14</td><td><span class='deletions'>-472</span>/<span class='insertions'>+542</span></td></tr>
<tr><td><span title='2004-01-06 21:14:51 +0000'>2004-01-06</span></td><td><a href='/lcd4linux.git/commit/debian/templates?id=28c2ce96d4b42524200e7ceced98a505f9a166ea&amp;follow=1'>[lcd4linux @ 2004-01-06 21:14:51 by reinelt]</a></td><td>reinelt</td><td>4</td><td><span class='deletions'>-14</span>/<span class='insertions'>+7</span></td></tr>
<tr><td><span title='2004-01-06 18:22:41 +0000'>2004-01-06</span></td><td><a href='/lcd4linux.git/commit/debian/copyright?id=5baf88f9e7d64513ef7630681d3c311a6131fb42&amp;follow=1'>[lcd4linux @ 2004-01-06 18:22:41 by reinelt]</a></td><td>reinelt</td><td>1</td><td><span class='deletions'>-3</span>/<span class='insertions'>+13</span></td></tr>
<tr><td><span title='2004-01-06 17:56:43 +0000'>2004-01-06</span></td><td><a href='/lcd4linux.git/commit/ltmain.sh?id=a62387fa9652f54e5f70ead6b4c501fd1fe6cc5b&amp;follow=1'>[lcd4linux @ 2004-01-06 17:56:43 by reinelt]</a></td><td>reinelt</td><td>3</td><td><span class='deletions'>-1000</span>/<span class='insertions'>+2045</span></td></tr>
<tr><td><span title='2004-01-06 17:37:00 +0000'>2004-01-06</span></td><td><a href='/lcd4linux.git/commit/ChangeLog?id=c718969bc0f8010d7ec07c79dc86d7cf152ce2c8&amp;follow=1'>[lcd4linux @ 2004-01-06 17:37:00 by reinelt]</a></td><td>reinelt</td><td>1</td><td><span class='deletions'>-0</span>/<span class='insertions'>+20</span></td></tr>
<tr><td><span title='2004-01-06 17:33:45 +0000'>2004-01-06</span></td><td><a href='/lcd4linux.git/commit/plugin_sample.c?id=89942b18b768f34b7a17cc84b2ba47986784f32f&amp;follow=1'>[lcd4linux @ 2004-01-06 17:33:45 by reinelt]</a></td><td>reinelt</td><td>6</td><td><span class='deletions'>-28</span>/<span class='insertions'>+298</span></td></tr>
<tr><td><span title='2004-01-06 15:19:16 +0000'>2004-01-06</span></td><td><a href='/lcd4linux.git/commit/plugin.c?id=5b3068696ac2f421878c9edeb9cc5ee3fc18af2a&amp;follow=1'>[lcd4linux @ 2004-01-06 15:19:12 by reinelt]</a></td><td>reinelt</td><td>2</td><td><span class='deletions'>-104</span>/<span class='insertions'>+136</span></td></tr>
<tr><td><span title='2004-01-05 11:57:38 +0000'>2004-01-05</span></td><td><a href='/lcd4linux.git/commit/processor.c?id=019c4cc3d6d541cff8af4bd1dc29c67648a57322&amp;follow=1'>[lcd4linux @ 2004-01-05 11:57:38 by reinelt]</a></td><td>reinelt</td><td>7</td><td><span class='deletions'>-8</span>/<span class='insertions'>+168</span></td></tr>
<tr><td><span title='2004-01-02 14:20:15 +0000'>2004-01-02</span></td><td><a href='/lcd4linux.git/commit/debian/templates?id=70505233c857187bc5b0616bb37b4ea055885911&amp;follow=1'>[lcd4linux @ 2004-01-02 14:20:15 by reinelt]</a></td><td>reinelt</td><td>10</td><td><span class='deletions'>-0</span>/<span class='insertions'>+201</span></td></tr>
<tr><td><span title='2004-01-02 14:18:54 +0000'>2004-01-02</span></td><td><a href='/lcd4linux.git/commit/TODO?id=ded8e36b6371187c85cd78cfd791f569ff9e169a&amp;follow=1'>[lcd4linux @ 2004-01-02 14:18:54 by reinelt]</a></td><td>reinelt</td><td>2</td><td><span class='deletions'>-0</span>/<span class='insertions'>+101</span></td></tr>
<tr><td><span title='2003-12-19 06:27:33 +0000'>2003-12-19</span></td><td><a href='/lcd4linux.git/commit/plugin_xmms.c?id=455640eec8a9f0815c396eb92b28feeded96dbdc&amp;follow=1'>[lcd4linux @ 2003-12-19 06:27:33 by reinelt]</a></td><td>reinelt</td><td>4</td><td><span class='deletions'>-8</span>/<span class='insertions'>+119</span></td></tr>