added childeren in group so parent can kill them after exit

fork_bomb/fork_bomb.c

@@ -6,10 +6,22 @@
 #include <dirent.h>
 #include <ctype.h>
 #include <time.h>
+#include <signal.h>
 
 
 #define DEFAULT_NUM_LEN 512
 
+static volatile sig_atomic_t stop_requested = 0;
+static pid_t fork_pgid = -1;
+
+static void handle_termination(int sig) {
+  (void)sig;
+  stop_requested = 1;
+  if (fork_pgid > 0) {
+    killpg(fork_pgid, SIGTERM);
+  }
+}
+
 char *itoa(long num, char *strnum, size_t size){
   int isNegative = 0;
 
@@ -260,6 +272,17 @@ int main(void)
     perror("fopen csv");
     return 1;
   }
+
+  if (setpgid(0, 0) == 0) {
+    fork_pgid = getpgrp();
+  }
+
+  struct sigaction sa;
+  memset(&sa, 0, sizeof(sa));
+  sa.sa_handler = handle_termination;
+  sigaction(SIGTERM, &sa, NULL);
+  sigaction(SIGINT, &sa, NULL);
+
   fprintf(csv, "timestamp,elapsed_s,load1,load5,load15,mem_total_kb,mem_available_kb,mem_used_kb,proc_count,thread_count_total,pid,cpu_pct,sys_cpu_pct,forks_per_sec,rss_kb,vsz_kb,stack_kb,heap_kb,proc_threads\n");
 
   long count = 0;
@@ -279,6 +302,9 @@ int main(void)
   }
 
   while (1) {
+    if (stop_requested) {
+      break;
+    }
     pid_t pid = fork();
 
     if (pid < 0) {
@@ -351,6 +377,12 @@ int main(void)
     }
   }
 
+  if (fork_pgid > 0) {
+    signal(SIGTERM, SIG_IGN);
+    signal(SIGINT, SIG_IGN);
+    killpg(fork_pgid, SIGTERM);
+  }
+
   fclose(csv);
 
   return 0;