FreeBSD reaper API demo

reaperdemo.c

#include <sys/procctl.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sysexits.h>
#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <unistd.h>
#include <signal.h>

int main() {
        srandomdev();
        if (procctl(P_PID, getpid(), PROC_REAP_ACQUIRE, NULL) == -1) err(EX_OSERR, NULL);
        printf("reaper: %d\n", getpid());
        pid_t one, two;
        if ((one = fork()) == 0) {
                printf(" one: %d\n", getpid());
                usleep(1000 * (random() % 1000 + 200));
                if ((one = fork()) == 0) {
                        printf(" one.child: %d\n", getpid());
                        usleep(1000 * (random() % 1000 + 200));
                        if ((one = fork()) == 0) {
                                printf(" one.child.child1: %d\n", getpid());
                                while (true) {
                                        printf(" one.child.child1 looping\n");
                                        usleep(1000 * 250);
                                }
                        }
                        usleep(1000 * (random() % 1000 + 200));
                        if ((one = fork()) == 0) {
                                printf(" one.child.child2: %d\n", getpid());
                                while (true) {
                                        printf(" one.child.child2 looping\n");
                                        usleep(1000 * 250);
                                }
                        }
                        usleep(1000 * (random() % 1000 + 200));
                        printf(" one.child: return\n");
                        return 0;
                }
                printf(" one: return\n");
                return 0;
        }
        if ((two = fork()) == 0) {
                printf(" two: %d\n", getpid());
                sleep(1);
                if ((two = fork()) == 0) {
                        printf(" two.child: %d\n", getpid());
                        while (true) {
                                printf(" two.child looping\n");
                                sleep(1);
                        }
                }
                printf(" two: return\n");
                return 0;
        }
        int cnt = 0;
        while (true) {
                usleep(1000 * 500);
                int status = -1;
                struct rusage usage = {0};
                pid_t reaped = -1;
                while ((reaped = wait3(&status, WNOHANG, &usage)) != 0 && reaped != -1)
                        printf("reaper: reaped %d\n", reaped);
                struct procctl_reaper_pidinfo infos[10] = {0};
                struct procctl_reaper_pids inforeq = { .rp_count = 10, .rp_pids = infos };
                if (procctl(P_PID, getpid(), PROC_REAP_GETPIDS, &inforeq) == -1) err(EX_OSERR, NULL);
                printf("reaper: children:\n");
                for (size_t i = 0; i < inforeq.rp_count; i++)
                        if (infos[i].pi_pid != 0)
                                printf("- pid %d of subtree %d\n", infos[i].pi_pid, infos[i].pi_subtree);
                struct procctl_reaper_kill killreq = {
                        .rk_sig = SIGTERM,
                        .rk_flags = REAPER_KILL_SUBTREE,
                        .rk_subtree = one,
                        .rk_killed = -1,
                        .rk_fpid = -1,
                };
                cnt++;
                if (cnt == 10) {
                        printf("reaper: killing one's descendants\n");
                        if (procctl(P_PID, getpid(), PROC_REAP_KILL, &killreq) == -1) err(EX_OSERR, NULL);
                        printf("reaper: killed %d procs\n", killreq.rk_killed);
                }
                if (cnt == 15) {
                        printf("reaper: killing two's descendants\n");
                        killreq.rk_subtree = two;
                        if (procctl(P_PID, getpid(), PROC_REAP_KILL, &killreq) == -1) err(EX_OSERR, NULL);
                        printf("reaper: killed %d procs\n", killreq.rk_killed);
                }
                if (cnt == 16) {
                        printf("reaper: done\n");
                        return 0;
                }
        }
}

reaperdemo.log

reaper: 30368
 one: 30369
 two: 30370
 one: return
 one.child: 30371
reaper: reaped 30369
reaper: children:
- pid 30371 of subtree 30369
- pid 30370 of subtree 30370
 one.child.child1: 30372
 one.child.child1 looping
 two: return
 two.child: 30373
 two.child looping
reaper: children:
- pid 30373 of subtree 30370
- pid 30372 of subtree 30369
- pid 30371 of subtree 30369
- pid 30370 of subtree 30370
 one.child.child1 looping
 one.child.child1 looping
reaper: reaped 30370
reaper: children:
- pid 30373 of subtree 30370
- pid 30372 of subtree 30369
- pid 30371 of subtree 30369
 one.child.child2: 30374
 one.child.child2 looping
 one.child.child1 looping
 one.child.child2 looping
reaper: children:
- pid 30374 of subtree 30369
- pid 30373 of subtree 30370
- pid 30372 of subtree 30369
- pid 30371 of subtree 30369
 one.child.child1 looping
 two.child looping
 one.child.child2 looping
 one.child.child1 looping
 one.child.child2 looping
reaper: children:
- pid 30374 of subtree 30369
- pid 30373 of subtree 30370
- pid 30372 of subtree 30369
- pid 30371 of subtree 30369
 one.child.child1 looping
 one.child.child2 looping
 one.child.child1 looping
 one.child: return
reaper: reaped 30371
reaper: children:
- pid 30374 of subtree 30369
- pid 30373 of subtree 30370
- pid 30372 of subtree 30369
 two.child looping
 one.child.child2 looping
 one.child.child1 looping
 one.child.child2 looping
 one.child.child1 looping
reaper: children:
- pid 30374 of subtree 30369
- pid 30373 of subtree 30370
- pid 30372 of subtree 30369
 one.child.child2 looping
 one.child.child1 looping
 one.child.child2 looping
 one.child.child1 looping
reaper: children:
- pid 30374 of subtree 30369
- pid 30373 of subtree 30370
- pid 30372 of subtree 30369
 two.child looping
 one.child.child2 looping
 one.child.child1 looping
 one.child.child2 looping
 one.child.child1 looping
reaper: children:
- pid 30374 of subtree 30369
- pid 30373 of subtree 30370
- pid 30372 of subtree 30369
 one.child.child2 looping
 one.child.child1 looping
 one.child.child2 looping
 one.child.child1 looping
reaper: children:
- pid 30374 of subtree 30369
- pid 30373 of subtree 30370
- pid 30372 of subtree 30369
reaper: killing one's descendants
reaper: killed 2 procs
 two.child looping
reaper: reaped 30372
reaper: reaped 30374
reaper: children:
- pid 30373 of subtree 30370
 two.child looping
reaper: children:
- pid 30373 of subtree 30370
reaper: children:
- pid 30373 of subtree 30370
 two.child looping
reaper: children:
- pid 30373 of subtree 30370
reaper: children:
- pid 30373 of subtree 30370
reaper: killing two's descendants
reaper: killed 1 procs
reaper: reaped 30373
reaper: children:
reaper: done