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<stdio.h>#include<stdlib.h> #include<string.h> #define PIPESIZE 8 enum Status { RUN, WAIT, READY };#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->)) {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->, 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->, 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->)){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->, 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->,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; elseconsumer->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 <PIPESIZE; low++) printf("| |");}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->); 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->); p = p->next;}}else printf("CONSUMER ready\n ");} 实验结果：。