Operating system third experiment report: pipeline

0. Personal information

• Name Lei Tanchun
• Student ID 201821121030
• Class calculation 1811

1. Write a program

Create a named pipe and create two processes to read and write to the pipe:

//fifo_write

#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <signal.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
void handle_sig(int sig)
{
    printf("signal pipe\n");
    exit(-1);
}

int main(int argc,
{argv)**char
    int fd;
     int ret;
     char buf [ 128 ];
     int i = 0 ; 

    / * Process pipeline signal * / 
    signal (SIGPIPE, handle_sig); 
    if (mkfifo ( " ./fifo " , 0640 ) ==- 1 ) 
    { 
        if (errno! = EEXIST) 
        { 
            perror ( " mkfifo " );
             return - 1 ; 
        } 
    } 
    / * open the pipeline in write-only mode * / 
    fd= open("./fifo", O_WRONLY); 
    if(fd == -1)
    {
        perror("open");
        return -1;
    }

    while(1)    
    {
        scanf("%s",buf);
        //sprintf(buf, "data %d", i++);
    /*往管道写数据*/
        ret = write(fd, buf, strlen(buf));

        printf("write fifo [%d] %s\n", ret, buf);

        sleep(1);
    }
    return 0;
}

//fifo_read

#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <signal.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>

int main(int argc, char** argv)
{
    int fd;
    int ret;
    char buf[128];
    if(mkfifo("./fifo", 0640) ==- 1 ) 
    { 
        if (errno! = EEXIST) / * If the error type is that a fifo file already exists, continue to execute * / 
        { 
            perror ( " mkfifo " );
             return - 1 ; 
        } 
    } 

    / * In read-only mode Open the pipeline * / 
    fd = open ( " ./fifo " , O_RDONLY); 
     if (fd ==- 1 ) 
    { 
        perror ( " open " );
         return - 1 ; 
    }

    while(1)    
    {
        memset(buf, 0, sizeof(buf));
        /*读管道*/
        if((sizeof(buf)-1))
        {
            ret = read(fd, buf, sizeof(buf) - 1);
    
               printf("read fifo [%d] : %s\n", ret, buf);
        }
    }
    return 0;
}

 

2. Operation result

1. Input

 

 

2. Output

 

 

3. Questions and answers generated through this experiment