/* SPDX-License-Identifier: ISC */
#include "init.h"

static void respawn(svc_run_data_t *rt)
{
	if (rt->svc->rspwn_limit > 0) {
		rt->rspwn_count += 1;

		if (rt->rspwn_count >= rt->svc->rspwn_limit)
			goto fail;
	}

	rt->pid = runsvc(rt->svc);
	if (rt->pid == -1)
		goto fail;

	rt->state = STATE_RUNNING;
	return;
fail:
	rt->state = STATE_FAILED;
	print_status(rt);
	return;
}

static svc_run_data_t *wait_for_process(void)
{
	svc_run_data_t *rt;
	int status;
	pid_t pid;

	do {
		pid = wait(&status);

		if (pid == -1) {
			if (errno == EINTR)
				return NULL;

			if (errno == ECHILD)
				exit(EXIT_FAILURE);
		}

		rt = config_rt_data_by_pid(pid);
	} while (rt == NULL);

	rt->status = WIFEXITED(status) ? WEXITSTATUS(status) : EXIT_FAILURE;
	rt->pid = -1;
	return rt;
}

static void handle_exited(svc_run_data_t *rt)
{
	if (rt->svc->type == SVC_RESPAWN) {
		if (config_should_respawn())
			respawn(rt);
	} else {
		if (rt->status == EXIT_SUCCESS) {
			rt->state = STATE_COMPLETED;
		} else {
			rt->state = STATE_FAILED;
		}

		print_status(rt);
	}
}

static void start_service(svc_run_data_t *rt)
{
	if (rt->svc->flags & SVC_FLAG_HAS_EXEC) {
		rt->pid = runsvc(rt->svc);
		if (rt->pid == -1) {
			rt->state = STATE_FAILED;
		} else {
			rt->state = STATE_RUNNING;

			if (rt->svc->type == SVC_WAIT)
				config_set_waiting(rt);
		}
	} else {
		rt->status = EXIT_SUCCESS;
		rt->state = STATE_COMPLETED;
	}

	print_status(rt);
}

static void handle_signal(int signo)
{
	switch (signo) {
	case SIGTERM:
		config_set_target(TGT_SHUTDOWN);
		break;
	case SIGINT:
		config_set_target(TGT_REBOOT);
		break;
	case SIGHUP:
		break;
	case SIGUSR1:
		break;
	}
}

int main(void)
{
	svc_run_data_t *rt;
	struct sigaction act;

	if (config_load())
		return EXIT_FAILURE;

	memset(&act, 0, sizeof(act));
	act.sa_handler = handle_signal;

	sigaction(SIGTERM, &act, NULL);
	sigaction(SIGINT, &act, NULL);
	sigaction(SIGHUP, &act, NULL);
	sigaction(SIGUSR1, &act, NULL);

	if (reboot(LINUX_REBOOT_CMD_CAD_OFF))
		perror("cannot disable CTRL+ALT+DEL");

	for (;;) {
		rt = config_dequeue();

		if (rt == NULL) {
			rt = wait_for_process();
			if (rt == NULL)
				continue;

			handle_exited(rt);
		} else {
			start_service(rt);
		}
	}

	return EXIT_SUCCESS;
}