/* 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;

	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);

		if (rt->svc->type == SVC_ONCE)
			config_singleshot_terminated();
	}

	return 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;
	}
}

static void check_target_completion(void)
{
	if (!config_is_current_target_complete())
		return;

	switch (config_get_current_target()) {
	case TGT_BOOT:
		break;
	case TGT_SHUTDOWN:
		for (;;)
			reboot(RB_POWER_OFF);
		break;
	case TGT_REBOOT:
		for (;;)
			reboot(RB_AUTOBOOT);
		break;
	}
}

int main(void)
{
	svc_run_data_t *rt, *terminated;
	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) {
			terminated = wait_for_process();

			if (terminated == NULL)
				continue;
		} else if (rt->svc->flags & SVC_FLAG_HAS_EXEC) {
			rt->pid = runsvc(rt->svc);

			if (rt->pid == -1) {
				rt->state = STATE_FAILED;
				print_status(rt);
			} else {
				rt->state = STATE_RUNNING;
				print_status(rt);

				switch (rt->svc->type) {
				case SVC_WAIT:
					do {
						terminated = wait_for_process();
					} while (terminated != rt);
					break;
				case SVC_ONCE:
					config_singleshot_started();
					break;
				}
			}
		} else {
			rt->status = EXIT_SUCCESS;
			rt->state = STATE_COMPLETED;
			print_status(rt);
		}

		check_target_completion();
	}

	return EXIT_SUCCESS;
}