pc11.c

#define __LIBRARY__
#include	<stdio.h>
#include	<stdlib.h>
#include	<unistd.h>
#include	<linux/kernel.h>
#include	<fcntl.h>
#include	<sys/types.h>
#define BUFFERSIZE	10

static _syscall2(sem_t *,sem_open,const char *,name,int,value);
static _syscall1(int,sem_post,sem_t *,sem);
static _syscall1(int,sem_wait,sem_t *,sem);
static _syscall1(int,sem_getvalue,sem_t *,sem);
static _syscall1(int,sem_unlink,const char*,name);

sem_t *empty;
sem_t *full;
sem_t *mutex;

int main(void)
{

	char err_desc[255];
	char empty_sem[]= "empty";
	char full_sem[]= "full";
	char mutex_sem[]="mutex";

	int in = open("pc.log", O_CREAT|O_TRUNC|O_RDWR, 0666);
	int of = open("pc.log", O_CREAT|O_TRUNC|O_RDWR, 0666);
	int log = open("pclog.log", O_CREAT|O_TRUNC|O_RDWR, 0666);
	char buflog[255];

	int tmp;

	int itemValue = -1;
	int fileLen,tmpValue,i,j;

	if(fcntl(in,F_CHSIZE,0)!=0)
	{
		printf("in main process. ftruncate error!\n");
		close(in);
		close(of);
		return 0;
	}
	empty = sem_open(empty_sem,BUFFERSIZE);

	if(empty == NULL)
	{
		printf("create semaphore empty error!\n");
		exit(1);
	}	

	full = sem_open(full_sem,0);
	if(full ==NULL)
	{
		printf("create semaphore full error!\n");
		exit(1);
	}
	
	mutex = sem_open(mutex_sem,1);
	if(mutex == NULL)
	{
		printf("create semaphore mutex error!\n");
		exit(1);
	}
	
	tmpValue=sem_getvalue(empty);
	printf("now empty's value = %d\n",tmpValue);

	tmpValue=sem_getvalue(mutex);
	printf("now mutex's value = %d\n",tmpValue);

	tmpValue=sem_getvalue(full);
	printf("now full's value = %d\n",tmpValue);
	
	if(!fork())
	{
		printf("producer process %u !now itemValue=%d\n",getpid(),itemValue);
		
		while(itemValue<50)
		{
			itemValue++;

			if(sem_wait(empty)!=0)
			{
				printf("in producer sem_wait(empty) error!\n");
				perror(err_desc);
				break;
			}
			

			if(sem_wait(mutex)!=0)
			{
				printf("in producer sem_wait(mutex) error!\n");
				perror(err_desc);

				break;
			}

			fileLen=lseek(in,0,SEEK_END);
			write(in,&itemValue,sizeof(itemValue));

			
			if(sem_post(mutex)!=0)
			{
				printf("in producer sem_post(mutex) error!\n");
				perror(err_desc);
				break;
			}

			if(sem_post(full)!=0)
			{
				printf("in producer sem_post(full) error!\n");
				perror(err_desc);
				break;
			}

		}

		tmpValue=sem_getvalue(empty);
		printf("now empty's value = %d\n",tmpValue);

		tmpValue=sem_getvalue(mutex);
		printf("now mutex's value = %d\n",tmpValue);

		tmpValue=sem_getvalue(full);
		printf("now full's value = %d\n",tmpValue);

		while(1)
			;

		close(in);
	}
	
	for(i=0; i < 5; i++)
	{
		if(!fork())
		{
			printf("customer process(%u) begin to run!\n",getpid());

			while(1)
			{
			

				if(sem_wait(full)!=0)
				{
					printf("in customer %u sem_wait(full) error!\n",getpid());
					perror(err_desc);
					break;
				}
	
				if(sem_wait(mutex)!=0)
				{
					printf("in customer %u,sem_post(empty) error!",getpid());
					perror(err_desc);
					break;
				}

				lseek(of,0,SEEK_SET);
				read(of,&itemValue,sizeof(itemValue));
				/*printf("%u:%d\n",getpid(),itemValue);*/

				lseek(log,0,SEEK_END);
				sprintf(buflog,"%u:%d\n",getpid(),itemValue);
				write(log,&buflog,sizeof(char)*strlen(buflog));

				fileLen=lseek(in,0,SEEK_END);

				for(j=1;j<(fileLen/sizeof(itemValue));j++)
				{
					lseek(in,j*sizeof(itemValue),SEEK_SET);
					read(in,&tmpValue,sizeof(tmpValue));
					lseek(in,(j-1)*sizeof(itemValue),SEEK_SET);
					write(in,&tmpValue,sizeof(tmpValue));
				}

				if(fcntl(in,F_CHSIZE,fileLen-sizeof(tmpValue))!=0)
				{
					printf("ftruncate error!\n");
					break;
				}

				if(sem_post(mutex)!=0)
				{
					printf("in customer %u,sem_post(empty) error!\n",getpid());
					perror(err_desc);
					break;
				}

				if(sem_post(empty)!=0)
				{

					printf("in customer %u,sem_post(empty) error!\n",getpid());
					perror(err_desc);

				}
			}

			close(of);
		}
	}
	
	printf("now, main process exit!\n");

	return 0;
}