OS实验一 进程控制

实验一  进程控制

简单了解：

信号量：https://blog.youkuaiyun.com/dlutbrucezhang/article/details/8821690

管道机制：https://blog.youkuaiyun.com/rengui1228/article/details/72977797

1、编写程序，演示多进程并发执行和进程软中断、管道通信

#include<signal.h>
#include<sys/types.h>
#include<sys/stat.h>
#include<unistd.h>
#include<fcntl.h>
#include<stdio.h>
#include<stdlib.h>
#include<errno.h>
#include<string.h>
 
#define N 30
#define MAX 100
 
int count=0;
int pid1,pid2;
int fd[2];
 
void func1(int sig1)
{
    kill(pid1,SIGUSR1);
    kill(pid2,SIGUSR1);
 
}

void func2(int sig2)
{
    close(fd[0]);
    close(fd[1]);
    if(pid1==0){
        printf("child1 end!\n");
        exit(0);
    }
    if(pid2==0){
        printf("child2 end!\n");
        exit(0);
    }
}
 
int pid1_read_pipe(int fd)
{
    char buf[N];
    int n=0;
    while(1){
        n=read(fd,buf,sizeof(buf));
        buf[n]='\0';
        printf("Read %d bytes : %s.\n",n,buf);
        sleep(1);
    }
    exit(0);
}
 
int pid2_write_pipe(int fd)
{
    char buf[MAX];
    while(1){
        sprintf(buf,"I send you %d times",count);
        printf("write: %s.\n",buf);
        count++;
        buf[strlen(buf)] = '\0';
        write(fd,buf,strlen(buf));
        sleep(1);
    }
    exit(0);
}
 
int main()
{
    if(pipe(fd) < 0){
        perror("Fail to pipe");
        exit(EXIT_FAILURE);
    }
    signal(SIGINT,func1);
    
    if((pid1=fork())<0){
        perror("Fail to fork");
        exit(EXIT_FAILURE);
    }else if(pid1==0){
        signal(SIGINT,SIG_IGN);
        signal(SIGUSR1,func2);
        close(fd[1]);
        pid1_read_pipe(fd[0]);
    }
    else{
        if((pid2=fork())<0){
            perror("Fail to fork");
            exit(EXIT_FAILURE);
        }
        else if(pid2==0){
            signal(SIGINT,SIG_IGN);
            signal(SIGUSR1,func2);
            close(fd[0]);
            pid2_write_pipe(fd[1]);
        }
    }
    waitpid(pid1,NULL,0);
    printf("Child Process 1 is killed by parent!\n");
    waitpid(pid2,NULL,0);
    printf("Child Process 2 is killed by parent!\n");
    return 0;
}

2、父进程使用系统调用pipe( )建立一个管道,然后使用系统调用fork()创建两个子进程，子进程1和子进程2；

子进程1每隔1秒通过管道向子进程2发送数据:

      I send you x times. (x初值为1，每次发送后做加一操作）

      子进程2从管道读出信息，并显示在屏幕上。

3、父进程用系统调用signal()捕捉来自键盘的中断信号（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 l is Killed by Parent!

         Child Process 2 is Killed by Parent!

4、父进程等待两个子进程终止后，释放管道并输出如下的信息后终止

   Parent Process is Killed!

5、运行结果

附：

父进程写，两个子进程读，代码如下：

#include<signal.h>
#include<sys/types.h>
#include<sys/stat.h>
#include<unistd.h>
#include<fcntl.h>
#include<stdio.h>
#include<stdlib.h>
#include<errno.h>
#include<string.h>
 
#define N 30
#define MAX 100

int pid1,pid2;
int fd[2];
 
void func1(int sig1)
{
    kill(pid1,SIGUSR1);
    kill(pid2,SIGUSR1);
 
}
 
 
 
void func2(int sig2)
{
    close(fd[0]);
    close(fd[1]);
    if(pid1==0){
        printf("child1 end!\n");
        exit(0);
    }
    if(pid2==0){
        printf("child2 end!\n");
        exit(0);
    }
}
 
int pid1_read_pipe(int fd)
{
    char buf[N];
    int n=0;
    while(1){
        n=read(fd,buf,sizeof(buf));
        buf[n]='\0';
        printf("pid1 Read %d bytes : %s.\n",n,buf);
        sleep(1);
    }
    exit(0);
}
 
int pid2_read_pipe(int fd)
{
    char buf[N];
    int n=0;
    while(1){
        n=read(fd,buf,sizeof(buf));
        buf[n]='\0';
        printf("pid2 Read %d bytes : %s.\n",n,buf);
        sleep(1);
    }
    exit(0);
}

int write_pipe(int fd)
{
    char buf[MAX];
    int count=0;
    for (int i=0; i < 10; i++){
        sprintf(buf,"I send you %d times",count);
        printf("write: %s.\n",buf);
        count++;
        buf[strlen(buf)] = '\0';
        write(fd,buf,strlen(buf));
        sleep(1);
    }
    return 0;
}

int main()
{
    if(pipe(fd) < 0){
        perror("Fail to pipe");
        exit(EXIT_FAILURE);
    }
    signal(SIGINT,func1);
    
    if((pid1=fork())<0){
        perror("Fail to fork");
        exit(EXIT_FAILURE);
    }else if(pid1==0){
        signal(SIGINT,SIG_IGN);
        signal(SIGUSR1,func2);
        close(fd[1]);
        pid1_read_pipe(fd[0]);
    }
    else{
        if((pid2=fork())<0){
            perror("Fail to fork");
            exit(EXIT_FAILURE);
        }
        else if(pid2 == 0){
            signal(SIGINT,SIG_IGN);
            signal(SIGUSR1,func2);
            close(fd[0]);
            pid2_read_pipe(fd[0]);
        }
    }

    write_pipe(fd[1]);
    waitpid(pid1,NULL,0);
    printf("Child Process 1 is killed by parent!\n");
    waitpid(pid2,NULL,0);
    printf("Child Process 2 is killed by parent!\n");
    return 0;
}

运行结果：