82 lines
2.6 KiB
C
82 lines
2.6 KiB
C
//
|
|
// Written for Computer Networks and Systems lab classes
|
|
// AUTHOR : Sergiusz Warga
|
|
|
|
#include <stdio.h>
|
|
#include <sys/types.h>
|
|
#include <sys/time.h>
|
|
#include <unistd.h>
|
|
#include <stdlib.h>
|
|
#include <signal.h>
|
|
#include <time.h>
|
|
|
|
const char * get_timestamp() {
|
|
struct timeval now;
|
|
gettimeofday(&now, NULL);
|
|
char buff[127];
|
|
sprintf(&buff, "us : %d", now.tv_usec);
|
|
return buff;
|
|
}
|
|
|
|
void parent_before_child() {
|
|
pid_t pid;
|
|
printf("\nparent_before_child()\n");
|
|
pid = fork();
|
|
if (pid == -1) { // If something went wrong.
|
|
perror("Fork: ");
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
if (pid != 0) { // If this is a parent process.
|
|
printf("===\n%s\nI am a parent.\nMy PID is: %d\n===", get_timestamp(), getpid());
|
|
sleep(1);
|
|
kill(getpid(), SIGTERM);
|
|
} else {
|
|
printf("===\n%s\nI am a child.\nMy PID is: %d\nMy PPID is: %d\n===", get_timestamp(), getpid(), getppid());
|
|
sleep(1);
|
|
printf("===\n%s\nI am a child.\nMy PID is: %d\nMy PPID is: %d\n===", get_timestamp(), getpid(), getppid());
|
|
sleep(1);
|
|
printf("===\n%s\nI am a child.\nMy PID is: %d\nMy PPID is: %d\n===", get_timestamp(), getpid(), getppid());
|
|
// When parent is killed PPID of its child process becomes 1 (and so the init process becomes a new parent).
|
|
}
|
|
}
|
|
|
|
void child_before_parent() {
|
|
pid_t pid;
|
|
printf("\nchild_before_parent()\n");
|
|
printf("PID before fork: %d\n", getpid());
|
|
pid = fork();
|
|
if (pid == -1) { // If something went wrong.
|
|
perror("Fork: ");
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
if (pid == 0) { // If this is a parent process.
|
|
printf("===\n%s\nI am a child.\nMy PID is: %d\nMy PPID is: %d\n===", get_timestamp(), getpid(), getppid());
|
|
sleep(1);
|
|
kill(getpid(), SIGTERM);
|
|
} else {
|
|
printf("===\n%s\nI am a parent.\nMy PID is: %d\n===", get_timestamp(), getpid());
|
|
sleep(1);
|
|
printf("===\n%s\nI am a parent.\nMy PID is: %d\n===", get_timestamp(), getpid());
|
|
sleep(1);
|
|
printf("===\n%s\nI am a parent.\nMy PID is: %d\n===", get_timestamp(), getpid());
|
|
}
|
|
}
|
|
|
|
|
|
int main() {
|
|
int status;
|
|
pid_t pid;
|
|
printf("%s: Grandparent process has PID: %d\n", get_timestamp(), getpid());
|
|
pid = fork();
|
|
if (pid == 0) { // If child process
|
|
printf("%s: Process with PID %d will execute funs.\n", get_timestamp(), getpid());
|
|
child_before_parent();
|
|
sleep(5);
|
|
parent_before_child();
|
|
sleep(5);
|
|
} else { // If parent process
|
|
printf("%s: Grandparent's child process has PID: %d\n", get_timestamp(), pid);
|
|
sleep(12);
|
|
}
|
|
return 0;
|
|
} |