/* $Id$ * $URL$ * * 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); }