driver_conductor.c

源码包中是我在学习Linux进程间通信时所写的关于五种通信方式（管道

/*
 * this program simulated a simple communication between dirver and conductor.
 * conductor tell diver to begin driving via signal SIGINT(Ctrl + c), and stoping via signal SIGQUIT(Ctrl + \)
 * dirver tell conductor to notice all the passenger get off the bus when bus arrive at station via signal(SIGHUP)
 */ 
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>
#include <sys/types.h>

pid_t	pid1;

void sig1( int sig_no )
{
	if( sig_no == 2 )
	{
		kill( getppid(), 10 );		/* tell driver to drive the bus */	
	}
	else if( sig_no == 3 )
	{
		kill( getppid(), 12 );		/* tell driver to stop the bus */
	}
	else if( sig_no == 10)
	{
		printf( "I have stopped the bus, all the passenger can get off now!\n");	/* recieve the signal 10 from driver */
	}
}

void sig2( int sig_no )
{
	if( sig_no == 10 )
	{
		printf( "All the passenger have got on the bus, let's go!\n" );			/* recieve the signal 10 from conductor */
	
	}
	else if( sig_no == 12 )
	{
		printf( "We have arrived at bus station, please stop the car!\n" );		/* recieve the signal 12 from conductor */
	}
	else if( sig_no == 1 )
	{
		kill( pid1, 10 );								/* tell conductor the bus has arrivaled at station */
	}
}

int main()
{
	while( (pid1 = fork()) == -1 )			/* create a child process */
                ;
	/* conductor is child process */ 
	if( pid1 == 0 )		
	{
		while(1)
		{
			signal( SIGINT, sig1 );
			signal( SIGQUIT, sig1 );
			signal( 10, sig1 );
		}
	}
	/* driver is parent process */
	else
	{	
		printf( "parent process id = %d\n", getpid() );
		signal( SIGINT, SIG_IGN	);
		signal( SIGQUIT, SIG_IGN );
	
		signal( SIGHUP, sig2 );
		signal( 10, sig2 );			/* signal 10 represent signal SIGUSR1 */
		signal( 12, sig2 );			/* signal 12 represent signal SIGUSR2 */
	
		while(1)
		{
			pause();
			pause();
		}
	}
}