Ex02-Linux Process API-fork(), wait(), exec()
Operating systems Lab exercise
To write C Program that uses Linux Process API - fork(), wait(), exec()
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.
Write the C Program using Linux Process API - fork(), wait(), exec()
Test the C Program for the desired output.
#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
int main(void)
{ //variable to store calling function's process id
pid_t process_id;
//variable to store parent function's process id
pid_t p_process_id;
//getpid() - will return process id of calling function
process_id = getpid();
//getppid() - will return process id of parent function
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; }
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
int main() {
int pid;
pid = fork();
if (pid == -1) {
perror("fork");
exit(EXIT_FAILURE);
}
else if (pid == 0) {
printf("I am child, my pid is %d\n", getpid());
printf("My parent pid is: %d\n", getppid());
exit(EXIT_SUCCESS);
}
else {
printf("I am parent, my pid is %d\n", getpid());
sleep(100);
exit(EXIT_SUCCESS);
}
return 0;
}
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
int main() {
pid_t pid = fork();
if (pid < 0) {
perror("Fork failed");
exit(EXIT_FAILURE);
} else if (pid == 0) {
printf("This is the child process. Executing 'ls' command.\n");
execl("/bin/ls", "ls", "-l", NULL); // Lists files in long format
perror("execl failed");
exit(EXIT_FAILURE);
} else {
int status;
waitpid(pid, &status, 0); // Wait for the child to finish
if (WIFEXITED(status)) {
printf("Child process exited with status %d.\n", WEXITSTATUS(status));
} else {
printf("Child process did not exit normally.\n");
}
printf("Parent process is done.\n");
}
return 0;
}
The programs are executed successfully.