producerandconsumer.c

操作系统著名源代码

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <pthread.h>
#include <semaphore.h>

#define N 2   // 消费者或者生产者的数目
#define M 10 // 缓冲区里的数目

int in = 0;   // 生产者放置产品的位置
int out = 0; // 消费者取产品的位置

int buff[M] = {0}; // 缓冲区初始化为0， 开始时没有产品

sem_t empty_sem; // 同步信号量， 为空的时候消费者不能消费
sem_t full_sem;   // 同步信号量， 为满的时候生产者不能生产
pthread_mutex_t mutex; // 互斥锁申明

int producer_id = 0;   //生产者id
int consumer_id = 0; //消费者id

/* 打印缓冲区当前情况 */
void print()
{
int i;
for(i = 0; i < M; i++)
   printf("%d ", buff[i]);
printf("\n");
}


/*syscall：系统调用转换va（虚拟地址）为revert（物理地址）*/
void printadd(unsigned long va,unsigned long pid)

{

printf("vitual address:0x%lx\n",va);

unsigned long revert=syscall(333,va,pid);

printf("phisical address: 0x%lx\n\n",revert);
}

/* 生产者方法 */ 
void *producer()
{
int id = ++producer_id;
unsigned long va;

unsigned long pid;

pid =getpid();
while(1)
{
   // 用sleep的数量可以调节生产和消费的速度，便于观察
   sleep(1);
   //sleep(1);
  
   sem_wait(&full_sem);//如果为满则不能生产
   pthread_mutex_lock(&mutex);//上锁
  
   in = in % M;
   printf("producer %d in %d. like: \t", id, in);
   
   buff[in] = 1;  
   
   va=((unsigned) &buff[in]);
   print(); 
   
   printadd(va,pid);
   ++in;
   
   pthread_mutex_unlock(&mutex);//解锁
   sem_post(&empty_sem);  
}
}

/* 消费者方法 */
void *consumer()
{
int id = ++consumer_id;

unsigned long va;

unsigned long pid;

pid = getpid();
while(1)
{
   // 用sleep的数量可以调节生产和消费的速度，便于观察
   sleep(1);
//sleep(1);
  
   sem_wait(&empty_sem);
   pthread_mutex_lock(&mutex);
  
   out = out % M;
   printf("consumer %d in %d. like: \t", id, out);
  
   buff[out] = 0;
   va=((unsigned)&buff[out]);
   print();
   printadd(va,pid);
   ++out;
  
   pthread_mutex_unlock(&mutex);
   sem_post(&full_sem);
}
}

int main()
{
pthread_t id1[N];
pthread_t id2[N];
int i;
int ret[N];

// 初始化同步信号量
int ini1 = sem_init(&full_sem, 0, M); 
int ini2 = sem_init(&empty_sem, 0, 0);  
if(ini1 && ini2 != 0)
{
   printf("sem init failed \n");
   exit(1);
} 
//初始化互斥锁
int ini3 = pthread_mutex_init(&mutex, NULL);
if(ini3 != 0)
{
   printf("mutex init failed \n");
   exit(1);
} 
// 创建N个生产者线程
for(i = 0; i < N; i++)
{
   ret[i] = pthread_create(&id1[i], NULL, producer, (void *)(&i));
   if(ret[i] != 0)
   {
    printf("producer %d creation failed \n", i);
    exit(1);
   }
}
//创建N个消费者线程
for(i = 0; i < N; i++)
{
   ret[i] = pthread_create(&id2[i], NULL, consumer, NULL);
   if(ret[i] != 0)
   {
    printf("consumer %d creation failed \n", i);
    exit(1);
   }
}
//销毁线程
for(i = 0; i < N; i++)
{
   pthread_join(id1[i],NULL);
   pthread_join(id2[i],NULL);
}

exit(0); 
}