Linux-Process-API-fork-wait-exec-

Ex02-Linux Process API-fork(), wait(), exec()

Ex02-OS-Linux-Process API - fork(), wait(), exec()

Operating systems Lab exercise

AIM:

To write C Program that uses Linux Process API - fork(), wait(), exec()

DEVELOPED BY:
NAME: MANIKANDAN M
REG NO:212224040184

DESIGN STEPS:

Step 1:

Navigate to any Linux environment installed on the system or installed inside a virtual environment like virtual box/vmware or online linux JSLinux (https://bellard.org/jslinux/vm.html?url=alpine-x86.cfg&mem=192) or docker.

Step 2:

Write the C Program using Linux Process API - fork(), wait(), exec()

Step 3:

Test the C Program for the desired output.

C Program to print process ID and parent Process ID using Linux API system calls

PROGRAM:

CODE :

#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
int main(void)
{	gcc 
	pid_t process_id;
	pid_t p_process_id;
	process_id = getpid();
	p_process_id = getppid();


	printf("The process id: %d\n",process_id);
	printf("The process id of parent function: %d\n",p_process_id);
	return 0;
 }

OUTPUT :

C Program to create new process using Linux API system calls fork() and exit()

CODE :

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/wait.h>  

int main() {
    pid_t pid = fork();

    if (pid < 0) {
        perror("Fork failed");
        exit(1);
    }

    if (pid == 0) {
        printf("I am child, my PID is %d\n", getpid());
        printf("My parent PID is: %d\n", getppid());
        sleep(2);  
    } else {
        printf("I am parent, my PID is %d\n", getpid());
        wait(NULL);  
    }

    return 0;
}

OUTPUT

C Program to execute Linux system commands using Linux API system calls exec() family

CODE

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>

int main() {
    int status;
    pid_t pid;
    printf("Running ps with execl (no path)\n");
    pid = fork();
    if (pid == 0) {
        execl("ps", "ps", "ax", NULL);  
        perror("execl failed");
        exit(1);
    } else {
        wait(&status);
        if (WIFEXITED(status))
            printf("Child exited with status of %d\n", WEXITSTATUS(status));
        else
            puts("Child did not exit successfully");
    }

    printf("Running ps with execl (with /bin/ps path)\n");
    pid = fork();
    if (pid == 0) {
        execl("/bin/ps", "ps", "ax", NULL); 
        perror("execl failed");
        exit(1);
    } else {
        wait(&status);
        if (WIFEXITED(status))
            printf("Child exited with status of %d\n", WEXITSTATUS(status));
        else
            puts("Child did not exit successfully");
    }

    printf("Done.\n");
    return 0;
}

OUTPUT

RESULT:

The programs are executed successfully.