Question

unix question

please write a program and then show how to use top command that shows the zombie process, give

snapshot of top command that shows the zombie process

1. Write a very simple program that will show the possibility of having zombie processes. Write a program named zombie.c

The main process will create a child.

The child prints something like: “I am the child with pid ….. and my parent has ppid ….” Next, the child will sleep for 1 second.

Child exits.

The parent will print: I am the parent and my id is… Next, the parent sleeps for 30 seconds.

Since the child ends first, and the parent didn’t do wait( ), the child will be for a while in the zombie state. Run the parent in the background, so you can use the top command and identify the zombie, before the parent terminates.

Note: even if the parent terminates, the child is still a zombie. However the the init process reaps the zombies frequently.

Answer 1

Zombie.c

#include <stdlib.h>

#include <stdio.h>

#include<conio.h>

#include <unistd.h>

int main()

{

// fork() creates child process identical to parent

int pid = fork();

// if pid is greater than 0 than it is parent process

// if pid is 0 then it is child process

// if pid is -ve , it means fork() failed to create child process

if(pid<0)

{

//exit(1);

printf("failed to fork\n");

return -1;

}

//Parent Process

if(pid ==0)

{

sleep(1);

printf("I am the child process with pid %d and my parent has ppid %d\n ",getpid(),getppid());

exit(1);

}

else

{

printf("\nI am the parent and my id %d ",getpid());

sleep(30);

exit(0);

}

return 0;

}

#include <stdlib.h>

#include <stdio.h>

#include <unistd.h>

#include <string.h>

int main () {

system("./Assignment2a &");

system("ps -l");

sleep(3);

system("kill -9 $(ps -l|grep -w Z|tr -s ' '|cut -d ' ' -f 5)");

sleep(7);

printf("\n\nupdated list of processes with their states\n\n");

system("ps -l");

return(0);

}