aboutsummaryrefslogtreecommitdiffstats
path: root/thread.c
blob: 8e4e8e49570b6562be54dad27f45690f5f0ff93b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
/* $Id: thread.c,v 1.2 2004/03/20 07:31:33 reinelt Exp $
 *
 * thread handling (mutex, shmem, ...)
 *
 * Copyright 2004 Michael Reinelt <reinelt@eunet.at>
 * Copyright 2004 The LCD4Linux Team <lcd4linux-devel@users.sourceforge.net>
 *
 * parts of this code are based on the old XWindow driver which is
 * Copyright 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.
 *
 *
 * $Log: thread.c,v $
 * Revision 1.2  2004/03/20 07:31:33  reinelt
 * support for HD66712 (which has a different RAM layout)
 * further threading development
 *
 * Revision 1.1  2004/03/19 06:37:47  reinelt
 * asynchronous thread handling started
 *
 */

/* 
 * exported functions:
 * 
 * Fixme: document me!
 *
 */


#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


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


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


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


int shm_create (void **buffer, 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 (int shmid) 
{
  shmctl(shmid, IPC_RMID, NULL);
}


int thread_create (char *name, void (*thread)(char *name))
{
  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);
    thread(name);
    info ("thread %s ended.", name);
    exit (0);
  default:
    info ("forked process %d for thread %s", pid, name);
  }
  
  return pid;
}