东北大学操作系统实验三报告
操作系统实验报告班级物联网1302班
学号
姓名
实验 3 进程同步和通信-生产者和消费者问题模拟
1. 目的：
调试、修改、运行模拟程序，通过形象化的状态显示，使学生理解进程的概念，了解同步和通信的过程，掌握进程通信和同步的机制，特别是利用缓冲区进行同步和通信的过程。通过补充新功能，使学生能灵活运用相关知识，培养创新能力。
2. 内容及要求：
1) 调试、运行模拟程序。
2) 发现并修改程序中不完善的地方。
3) 修改程序，使用随机数控制创建生产者和消费者的过程。
4) 在原来程序的基础上，加入缓冲区的写互斥控制功能，模拟多个进程存取一个公共缓冲区，当有进程正在写缓冲区时，其他要访问该缓冲区的进程必须等待，当有进程正在读取缓冲区时，其他要求读取的进程可以访问，而要求写的进程应该等待。
5) 完成1) 、2) 、3)功能的,得基本分,完成4)功能的加2 分,有其它功能改进的再加2 分3. 程序说明：
本程序是模拟两个进程，生产者(producer)和消费者(Consumer)工作。生产者每次产生一个数据，送入缓冲区中。消费者每次从缓冲区中取走一个数据。缓冲区可以容纳8 个数据。因为缓冲区是有限的，因此当其满了时生产者进程应该等待，而空时，消费者进程应该等待；当生产者向缓冲区放入了一个数据，应唤醒正在等待的消费者进程，同样，当消费者取走一个数据后，应唤醒正在等待的生产者进程。就是生产者和消费者之间的同步。
每次写入和读出数据时，都将读和写指针加一。当读写指针同样时，又一起退回起点。当写指针指向最后时，生产者就等待。当读指针为零时，再次要读取的消费者也应该等待。
为简单起见，每次产生的数据为0-99 的整数，从0 开始，顺序递增。两个进程的调度是通过运行者使用键盘来实现的。
4. 程序使用的数据结构
进程控制块：包括进程名，进程状态和执行次数。缓冲区：一个整数数组。
缓冲区说明块：包括类型，读指针，写指针，读等待指针和写等待指针。
5. 程序使用说明
启动程序后，如果使用0键则运行一次生产者进程，使用'c'键则运行一次消费者进程。通过屏幕可以观察到两个进程的状态和缓冲区变化的情况。
6. 实验流程图
源程序
#include
#include
#define NORMAL 0 #define SLEEP 1 #define AWAKE 2 struct PCB
{
char name[3];
enum Status status;
int time;
};
struct waitqueue
{
struct PCB pcb;
struct waitqueue *next;
};
struct PCB *producer; /* write wait point */
struct PCB *consumer; /* read wait point */
struct waitqueue *headerqueue, *tailqueue;
int writeptr;
int readptr;
int writein, readout;
int buffer[PIPESIZE];
int empty, full;
void runp(char in[3]), runc(char in[3]), print();
int main()
{
char in[3]; writeptr = 0; readptr = 0; writein = 0; empty = PIPESIZE;
full = 0;
producer = (struct PCB *)malloc(sizeof(struct PCB)); consumer = (struct PCB
*)malloc(sizeof(struct PCB)); headerqueue = (struct waitqueue *)malloc(sizeof(struct waitqueue)); headerqueue->next = NULL;
tailqueue = headerqueue; producer->status = READY; consumer->status = WAIT;
producer->time = consumer->time = 0;
printf("Now starting the program!\n");
printf("Press 'p1' to run PRODUCER1,Press 'p1' to run PRODUCER2 \n"); printf("Press 'c1' to run CONSUMER1,Press 'c2' to run CONSUMER2 \n"); printf("Press 'e' to exit from the program.\n");
while (1)
{
strcpy(in, "N");
while (!strcmp(in, "N"))
{
printf("\n");
scanf("%s", in);
if (strcmp(in, "e") && strcmp(in, "p1") && strcmp(in, "p2") && strcmp(in, "c1") && strcmp(in, "c2"))
{
printf("error,please input again!!!\n");
strcpy(in, "N");
}
}
if ('p' == in[0])
{
runp(in);
producer->time++;
}
else if ('c' == in[0])
{
runc(in);
consumer->time++;
}
else
{
//printf("PRODUCER product %d times\n", producer->time);
//printf("CONSUMER consumer %d times\n", consumer->time); exit(0);
}
print();
printf("\n");
}
}
void runp(char in[3])
{
if (full >= 8)
{
struct waitqueue *search;
search = headerqueue->next;
while (search != NULL)
{ if (!strcmp(in, search->https://www.360docs.net/doc/172738910.html,)) {
printf("error!!!\n"); exit(1);
}
search = search->next;
}
producer->status = WAIT;
printf("PRODUCER %s process is waiting, can't be scheduled.\n", in); struct waitqueue *p = (struct waitqueue *)malloc(sizeof(struct waitqueue));
strcpy(p->https://www.360docs.net/doc/172738910.html,, in);
p->pcb.status = WAIT;
p->pcb.time = producer->time + 1; p->next = NULL;
tailqueue->next = p;
tailqueue = p;
full++;
}
else
{
writein = (writein + 1) % 100;
producer->status = RUN;
printf("run PRODUCER %s process . product %d ", in, writein); buffer[writeptr] = writein;
if (empty>8)
{
struct waitqueue *p; p = headerqueue->next; printf("run CONSUMER %s process. use %d", p->https://www.360docs.net/doc/172738910.html,, buffer[writeptr]);
if (tailqueue == p) {
tailqueue = headerqueue;
} headerqueue->next = p->next; free(p);
consumer->status = WAIT; empty--;
}
else
{
if (writeptr > readptr)
{
writeptr++;
if (writeptr >= PIPESIZE)
{
writeptr = 0;
if (readptr == 0) producer->status = WAIT;
else producer->status = READY;
}
}
else
{
writeptr++;
if (writeptr == readptr) producer->status = WAIT;
else producer->status = READY;
}
consumer->status = READY;
empty--;
full++;
}
}
}
void runc(char in[3])
{
if (empty >= 8)
{
struct waitqueue *search; search = headerqueue->next; while (search != NULL) { if (!strcmp(in, search->https://www.360docs.net/doc/172738910.html,))
{
printf("error!!!\n");
exit(1);
}
search = search->next;
}
consumer->status = WAIT;
printf("CONSUMER %s is waiting, can't be scheduled.\n",in); struct waitqueue *p = (struct waitqueue *)malloc(sizeof(struct waitqueue));
strcpy(p->https://www.360docs.net/doc/172738910.html,, in);
p->pcb.status = WAIT;
p->pcb.time = consumer->time + 1;
p->next = NULL; tailqueue->next = p; tailqueue = p; empty++;
} else
{ consumer->status = RUN; readout = buffer[readptr]; printf("run CONSUMER %s process. use %d ", in, readout); if (full>8)
{ writein = (writein + 1) % 100; buffer[writeptr] = writein; struct waitqueue *p; p = headerqueue->next;
printf("run PRODUCER %s process. product %d ", p->https://www.360docs.net/doc/172738910.html,,
buffer[writeptr]);
if (tailqueue == p) {
tailqueue = headerqueue;
} headerqueue->next = p->next; free(p);
producer->status = WAIT; full--;
writeptr++;
readptr++;
} else
{ if (readptr > writeptr) {
readptr++;
if (readptr >= PIPESIZE)
{ readptr = 0; if (writeptr == 0) consumer->status = WAIT; else
consumer->status = READY;
} else consumer->status = READY;
} else
{
readptr++;
if (readptr == writeptr)
{
consumer->status = WAIT; writeptr = readptr = 0;
}
else consumer->status = READY; producer->status = READY;
}
full--;
empty++;
}
}
}
void print()
{
int i = 0;
int j = 0;
int low = 0;
int high = 0;
printf("\n");
for (i; i < PIPESIZE; i++) printf(" ");
printf("\n");
if (readptr < writeptr)
{
for (low = 0; low < readptr; low++)
printf("| |");
for (low = readptr; low < writeptr; low++)
{
printf("| %2d |", buffer[low]);
}
for (low = writeptr; low } else if (readptr > writeptr) { for (low = 0; low < writeptr; low++) printf("| %2d |", buffer[low]); for (low = writeptr; low < readptr; low++) printf("| |"); for (low = readptr; low < PIPESIZE; low++) { printf("| %2d |", buffer[low]); } else if (producer->status == WAIT) { for (low = 0; low < PIPESIZE; low++) { printf("| %2d |", buffer[low]); } } else { for (low = 0; low < PIPESIZE; low++) { printf("| |"); } } printf("\n"); for (i = 0; i < PIPESIZE; i++) printf(" "); printf("\n"); if (producer->status == WAIT && NULL !=headerqueue->next) { struct waitqueue *p = headerqueue->next; while (NULL != p) { printf(" PRODUCER %s process are waitting\n", p->https://www.360docs.net/doc/172738910.html,); p = p->next; } } else printf("PRODUCER ready \n"); if (consumer->status == WAIT &&headerqueue->next) { struct waitqueue *p = headerqueue->next; while (NULL != p) { printf(" CONSUMER %s process are waitting\n", p->https://www.360docs.net/doc/172738910.html,); p = p->next; } } else printf("CONSUMER ready\n "); } 实验结果：