操作系统实验报告

1、武汉工程大学实验报告专业班级：网工 01 |姓名： 何彬|学号：1305120411课程名称：操作系统实验成绩:指导教师:蔡敦波 实验名称：进程控制与进程间通信一、实验目的：1、掌握进程的概念，明确进程和程序的区别。2、认识和了解并发执行的实质。3、了解什么是信号。4、熟悉LINUX系统中进程之间软中断通信的基本原理。二、实验内容：1、进程的创建(必做题)编写一段程序，使用系统调用fork()创建两个子进程，在系统中有一个父进程和两个子进程活动。让每个进程在屏幕上显示一个字符；父进程显示字符“a”，子进程分别显示字符 “b”和“c”。试观察记录屏幕上的显示结果，并分析原因。参考程序roat0h

2、ebin -# cat fork, c#include<stdio.h>pinclude<stdlib.h>int main() Int pl, p2;while(pl=fork() = -1);if(pl = 0)£putcharf * b *);p rintf("n") ; else while(p2=fork() = -1); if(p2 = 0)( putch«r( 'c 1 );printf (*'n"); else putchar( a ); printf (;root®he-bin

3、 -# vim fork. croothebin j# gcc fork. c -o forkroottghebln -# ./forkbc运行的结果是bca.首先创建进程p1,向子进程返回0,输出b.又创 建进程p2,向子进程返回0,输出c,同时向父进程返回子进程的 pid , 输出a2、修改已编写的程序，将每个进程的输出由单个字符改为一句话，再观察程序执行时屏幕上 出现的现象，并分析其原因。(必做题)参考程序# include<stdio.h> int main() int p1, p2, i;while(p1=fork()= = -1);if(p1= =0)for(i=0;i

4、<500;i+)printf( "child%dn” ,i);else while(p2=fork()= =-1);If(p2= =0)for(i=0;i<500;i+)printf( "son%d n” ,i);elsefor(i=0;i<500;i+)printf( "daughter%d n” ,i);9roothetin -# cat fork.c# include<stdio.h>#include<stdlib.h>Int maln() int pl, p2, 1;while(pl-fork(J) “ -1);i

5、f(pl = 6)for(i=Q;i<5;i+)printf(*,child good adn",i|; else while!(p2=Tork() = -1);!T(p2 = 0)for(i-0;i<5;i+)printf1"son is a good boydXn",i); elsefor(i=0;i<5;i+4-printf("daughter is a good girl%dn",i); rootghebin一vim fork.croatghebinT# gccfork.c -o forkroothebinHfcf#

6、./forkchild good0child good1child good2child good3child goodason is a goadboyBson is a goodboylson is a goodboy2son is a goodboy3son is a goadbay4daughter isagoodgi rl0daughter isagoodgirl1daughter isagoodgi12daughter isagoodgi13daughter isagoodgir14运行的结果是如上图所示.首先创建进程p1,向子进程返回0,并 for语句循环输出child +i字符

7、串.又创建进程p2,向子进程返回0,输 出字符串son+i,同时向父进程返回子进程的 pid ,输出字符串duaghter +i ,各打印5次。3、编写程序创建进程树如图 （选做题）1和图2所示，在每个进程中显示当前进程识别码和父进程识别码。实验一代码及结果raothebin cat tree.c#include<stdlo.h>ki nclu(1o<5trll i b. h>int p h.pZ c,p3 d;pl b = fork(;lf-(pl b > Dprirtf("process father a:pid = *dnr,qptpid，);el

8、se ifpl b = G) (printf t*child b:pid - father is dXn*y getpid (), getppid J j;<p2 c = 0jprintf("child c:pld =.father Is %dnw tgetpid(k getppidO;pl d = to rk();if(p3 jd = 0)printf tchlLd d; pid = %d - father is dn111getpldf) - ijetppidO !;process father a:pld 4571图一进程树实验结果及相关代码eg勘Mincat trq”，

9、工tinclu desftdlib T hoLnl udlnf) int uL U,cl :,。上也|>2_。； pl b = fork()： i.f ipl b k g(priMtcchild 馆:pir) - Mi t&tner is Myn-1 tpid(,',getrplclt);plc w tork(if(p) c = 0)print T('child c邛id - *d,Tatlwr is <tdn",getpid( .getppidC |)；alM if (pl b>9) (printr( -rather 1， Xin"

10、; .getpLdi)；p2_d = forkO;If (p2 dl « 91 (prlntfi -child dipid - *f*tXr is MMT76p1口。,qqtgWUh p3 e = fork!J;IfTpa e = Gprintf (child enpid = M. father is MJ'Me呼tpidf I 追讨口口idi H ;rootghebin ./tree2:hild b :pid 5152. father is 5151 rhild crpid = 5153Pfather 15 5152 rather is 5151= S1&4,fat

11、her is 51,S1 zhlld e：pld - 5155,father is 5154图二进程树实验结果及相关代码4、编写一段程序，使用系统调用fork()创建两个子进程，再用系统调用signal()让父进 程捕捉键盘上来的中断信号(即按ctrl+c键)，当捕捉到中断信号后，父进程用系统调用 kill() 向两个子进程发出信号，子进程捕捉到信号后，分别输出下列信息后终止：Child process 1 is killed by parent!Child process 2 is killed by parent!父进程等待两个子进程终止后，输出以下信息后终止：Parent process

12、 is killed!参考程序#include<stdio.h>#include<signal.h>#include<unistd.h>#include<sys/types : .h>#include<sys/wait.h>int wait_mark;void waiting(),stop();void main()int p1, p2;signal(SIGINT,stop);while(p1=fork()=-1);if(p1>0)/*在父进程中*/while(p2=fork()=-1);If(p2>0)/*在父进程中*/

13、wait_mark=1;waiting(0);kill(p1,10);kill(p2,12);wait( );wait( );printf("parent process is killed!n");exit(0);else/* 在子进程2 中 */wait_mark=1;signal(12,stop);waiting();lockf(1,1,0);printf("child process 2 is killed by parent!n");lockf(1,0,0);exit(0);else/* 在子进程1 中 */wait_mark=1;signal

14、(10,stop);waiting();lockf(1,1,0);printf("child process 1 is killed by parent!n");lockf(1,0,0);exit(0);void waiting()while(wait_mark!=0);void stop()wait_mark=0;实验要求：、运行程序并分析结果。roothebin 桌 面# ./progressACchild process 1 is killed by parent I child process 2 Is killed by parent! parent proces

15、s is killed!rootghebin 桌面#中断后，父进程收到子进程退出状态，依次杀死子进程2子进程1,等待子进程完全退出后，杀死父进程、如果把signal(SIGINT,stop)放在号和号位置，结果会怎样并分析原因。roothebin 桌面# ./progress"child p rocess 2 is killed by parent! parent process is killed!roothebin 桌面#改变signal(SIGINT,stop) 的位置后发现，只是杀死了子进程 2和 父进程，而子进程1没有被杀死。是因为子进程1没有设置对信号的处 理操作，则键盘

16、中断时，仍然无法将其杀死。、该程序段前面部分用了两个wait(0),为什么？wait(0)是为了让前面的子进程完全执行完，才可以进行下面的操作。、该程序段中每个进程退出时都用了语句exit(0),为什么？首先是为了让进程退出，其次是向父进程返回退出时的状态；5、修改上面的程序，增加语句 signal(SIGINT,SIG_IGN) 和语句 signal(SIGQUIT,SIG_IGN),再 观察程序执行时屏幕上出现的现象，并分析其原因。参考程序# include<stdio.h># include<signal.h># include<unistd.h>ma

17、in() int pid1, pid2;int EndFlag=0;Pf1=0;Pf2=0;void IntDelete()kill(pid1,10);kill(pid2,12);EndFlag=1;void Int1()printf( “ child process 1 is killed by parent !n” );exit(0);void Int2()printf( “ child process 2 is killed by parent !n” );exit(0);main()int exitcode;signal(SIGINT,SIG_IGN);signal(SIGQUIT,SIG_IGN);while(pid1=fork()=-1);if(pid=0)signal(SIGUSER1,Int1);signal(SIGQUIT,SIG_IGN);pause();exit(0);elsewhile(pid2=fork()= =-1);if(pid2=0)signal(SIGUSER1,Int1);signal(SIGQUIT,SIG_IGN);pause();exit(0);elsesignal(SIGINT,IntDelete);waitpid(-1,&exitcode,0);prin