操作系统_生产者与消费者问题的实现

1、河南师范大学计算机学院实验报告操作系统实验报告年月日学号XXX姓名XXX时间XXX专业XXX班级XXX-实验目的：通过生产者-消费者问题的模拟，加深对进程同步、共享存储器通信的理。实验内容与步骤:1 .启动LINUX操作系统，打开终端，输入命令"vis.c进入编辑页面编写程序，主要调用的函数有：<i>shmget()创建、获得一个共享存储区。<2>shmat()共享存储区的附接。从逻辑上将一个共享存储区附接到进程的虚拟地址空间上。<3>shmdt()把一个共享存储区从指定进程的虚地址空间断开。<4>shmctl()共享存储区的控制，对其

2、状态信息进行读取和修改。2 .编译原程序在终端输入命令"gcGlrts.c"若无错误再输入命令”./a.ou即运行出结果。(注：在命令"gcc-lrts.c'中，lrt选项是编译带有信号量的程序，命令”./a.out中./a.out是默认生成的原文件。)3 .实验所需程序及运行结果如下：(1)实验源程序：#include<stdio.h>#include<stdlib.h>#include<unistd.h>#include<sys/types.h>#include<sys/ipc.h>#incl

3、ude<sys/sem.h>#include<sys/mman.h>/提供了共享内存的相关操作#include<fcntl.h>#include<sys/stat.h>unionsemunintval;structsemid_ds*buf;unsignedshort*array;arg;生成信号量河南师范大学计算机学院实验报告intsem_creat(key_tkey,intvalue)(unionsemunsem;intsemid;sem.val=value;semid=semget(key,1,IPC_CREAT|0666);if(-1=se

4、mid)(printf("createsemaphoreerrorn");exit(-1);semctl(semid,0,SETVAL,sem);returnsemid;删除信号量voiddel_sem(intsemid)(unionsemunsem;sem.val=0;semctl(semid,0,IPC_RMID,sem);/p操作intp(intsemid)(structsembufsops=0,-1,SEM_UNDO;return(semop(semid,&sops,1);/v操作intv(intsemid)河南师范大学计算机学院实验报告(structsem

5、bufsops=0,+1,SEM_UNDO;return(semop(semid,&sops,1);intbuffer;int*pData;intvalue_read=0,value_write=0;intfull,empty;voidproducer(key_t,key_t);生产者所执行的代码voidconsumer(int,int);intmain(void)key_tkeyFull,keyEmpty;intfd;pid_tpid;void*ptr;指向共享内存的指针/*shm_open是一个POSIX函数，用来打开或创建一个与“/shm联的共享内存区*/if(fd=shm_op

6、en("/shm",O_RDWR|O_CREAT,S_IRUSR|S_IWUSR)=-1)printf("shm_openerror'n");/*出错提示*/if(ftruncate(fd,(sizeof(int)*5)=-1)/*截短共享内存的长度到我们所需要的长度*/printf("ftruncateerrorn");if(ptr=mmap(0,(sizeof(int)*5),PROT_READ|PROT_WRITE,MAP_SHARED,fd,0)=MAP_FAILED)/*将共享内存映射到进程地址空间*/河南师范大学计

7、算机学院实验报告(printf("mmaperror");)pData=(int*)ptr;keyFull=ftok("/",0);keyEmpty=ftok("/",5);full=sem_creat(keyFull,0);empty=sem_creat(keyEmpty,5);switch(pid=fork()(case-1:/*生成子进程失败*/break;case0:/*子进程*/producer(keyFull,keyEmpty);/*子进程是生产者*/sleep(2);break;default:consumer(full

8、,empty);/*父进程是消费者*/break;)wait(0);shm_unlink("/shm");/*删除共享内存区，程序中基本上保证了子进程先退出，因此父进程中无wait操作且这部操作放在父进程这里*/shmctl(shmid,IPC_RMID,&buf);return0;/del_sem(semid);)河南师范大学计算机学院实验报告/*生产者写5次后退出*/voidproducer(key_tkeyFull,key_tkeyEmpty)(intin=0;full=semget(keyFull,1,0);empty=semget(keyEmpty,1,0

9、);while(value_write<10)/*退出条件判定*/(printf("PrepareWrite'n");printf("emptyWriteP1:%dn",semctl(empty,0,GETVAL,0);p(empty);/*是否有空缓冲区，有则占有，无则被挂起，是原子操作*/printf("emptyWriteP2:%dn",semctl(empty,0,GETVAL,0);value_write+;in=in+;pDatain=value_write;in=in%5;printf("in=%

10、dn",in);printf("Write:%5dn",pDatain);printf("fullWriteV1:%dn",semctl(full,0,GETVAL,0);v(full);/*写完一个缓冲区，释放信号量full(值加1)*/printf("fullWriteV2:%dn",semctl(full,0,GETVAL,0);printf("WriteFinish'n");/sleep(1);)/*消费者读5次后退出*/voidconsumer(intfull,intempty)河南师范

11、大学计算机学院实验报告(intout=0;while(value_read<10)/*退出条件判定*/(printf("PrepareRead'n");printf("fullReadP1:%dn",semctl(full,0,GETVAL,0);p(full);/*获取信-号量*/printf("fullReadP2:%dn",semctl(full,0,GETVAL,0);value_read+;out=out+;pDataout=value_read;out=out%5;printf("out=%dn&q

12、uot;,out);printf("Read:%5dn",pDataout);printf("emptyReadV1:%dn",semctl(empty,0,GETVAL,0);*/v(empty);/*读完一个缓冲区，释放信号量empty(值加1)printf("emptyReadV2:%dn",semctl(empty,0,GETVAL,0);printf("ReadFinish'n");)(2)实验运行结果：rootlocalhost#gcc-lrts.crootlocalhost#./a.outPr

13、epareWriteemptyWriteP1:5emptyWriteP2:4in=1Write:1fullWriteV1:0河南师范大学计算机学院实验报告fullWriteV2:1WriteFinishPrepareWriteemptyWriteP1:4emptyWriteP2:3in=2Write:2fullWriteV1:1fullWriteV2:2WriteFinishPrepareWriteemptyWriteP1:3emptyWriteP2:2in=3Write:3fullWriteV1:2fullWriteV2:3WriteFinishPrepareWriteemptyWriteP

14、1:2emptyWriteP2:1in=4Write:4fullWriteV1:3fullWriteV2:4WriteFinishPrepareReadfullReadP1:4PrepareWritefullReadP2:3out=1河南师范大学计算机学院实验报告Read:1emptyReadV1:1emptyReadV2:2ReadFinishPrepareReadfullReadP1:3fullReadP2:2out=2Read:2emptyReadV1:2emptyReadV2:3ReadFinishPrepareReadfullReadP1:2fullReadP2:1out=3Read

15、:3emptyReadV1:3emptyReadV2:4ReadFinishPrepareReadfullReadP1:1fullReadP2:0out=4Read:4emptyReadV1:4emptyReadV2:5ReadFinishPrepareReadfullReadP1:0emptyWriteP1:2河南师范大学计算机学院实验报告emptyWriteP2:4in=0Write:5fullWriteV1:0fullWriteV2:0fullReadP2:0out=0Read:5emptyReadV1:4emptyReadV2:5ReadFinishPrepareReadfullRea

16、dP1:0WriteFinishPrepareWriteemptyWriteP1:5emptyWriteP2:4in=1Write:6fullWriteV1:0fullWriteV2:0fullReadP2:0out=1Read:6emptyReadV1:4emptyReadV2:5ReadFinishPrepareReadfullReadP1:0WriteFinishPrepareWrite河南师范大学计算机学院实验报告emptyWriteP1:5emptyWriteP2:4in=2Write:7fullWriteV1:0fullWriteV2:0fullReadP2:0out=2Read:

17、7emptyReadV1:4emptyReadV2:5ReadFinishPrepareReadfullReadP1:0WriteFinishPrepareWriteemptyWriteP1:5emptyWriteP2:4in=3Write:8fullWriteV1:0fullWriteV2:0fullReadP2:0out=3Read:8emptyReadV1:4emptyReadV2:5ReadFinishPrepareReadfullReadP1:0WriteFinish河南师范大学计算机学院实验报告PrepareWriteemptyWriteP1:5emptyWriteP2:4in=4Write:9fullWriteV1:0fullWriteV2:0fullReadP2:0out=4Read:9emptyReadV1:4emptyReadV2:5ReadFinishPrepareReadfullReadP1:0WriteFinishPrepareWriteemptyWriteP1:5emptyWriteP2:4in=0Write:10fullWriteV1:0fullWriteV2:0fullReadP2:0out=0Read:10emptyReadV1:4emptyReadV2:5ReadFinishWriteFinish