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

static void handle_exited(svc_run_data_t *rt, int status)
{
	rt->pid = -1;
	rt->status = WIFEXITED(status) ? WEXITSTATUS(status) : EXIT_FAILURE;
	rt->state = (rt->status == EXIT_SUCCESS) ?
		    STATE_COMPLETED : STATE_FAILED;

	if (rt->svc->type == SVC_RESPAWN && config_should_respawn()) {
		rt->state = STATE_FAILED;

		if (rt->svc->rspwn_limit > 0) {
			rt->rspwn_count += 1;

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

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

		rt->state = STATE_RUNNING;
		return;
	}
out_print:
	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 fd)
{
	struct signalfd_siginfo info;
	svc_run_data_t *rt;
	int status;
	pid_t pid;

	if (read(fd, &info, sizeof(info)) < (ssize_t)sizeof(info))
		return;

	switch (info.ssi_signo) {
	case SIGTERM:
		config_set_target(TGT_SHUTDOWN);
		break;
	case SIGINT:
		config_set_target(TGT_REBOOT);
		break;
	case SIGCHLD:
		while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
			rt = config_rt_data_by_pid(pid);

			if (rt != NULL)
				handle_exited(rt, status);
		}
		break;
	case SIGHUP:
		break;
	case SIGUSR1:
		break;
	}
}

int main(void)
{
	struct epoll_event ev;
	svc_run_data_t *rt;
	int ret, sfd, epfd;
	sigset_t sigmask;

	cli(NULL);

	if (config_load())
		return EXIT_FAILURE;

	epfd = epoll_create1(EPOLL_CLOEXEC);
	if (epfd < 0) {
		perror("epoll_create");
		return EXIT_FAILURE;
	}

	sigemptyset(&sigmask);
	sigaddset(&sigmask, SIGTERM);
	sigaddset(&sigmask, SIGINT);
	sigaddset(&sigmask, SIGHUP);
	sigaddset(&sigmask, SIGUSR1);
	sigaddset(&sigmask, SIGCHLD);

	sfd = signalfd(-1, &sigmask, SFD_CLOEXEC);
	if (sfd < 0) {
		perror("signalfd");
		return EXIT_FAILURE;
	}

	memset(&ev, 0, sizeof(ev));
	ev.events = EPOLLIN;
	ev.data.fd = sfd;

	if (epoll_ctl(epfd, EPOLL_CTL_ADD, sfd, &ev)) {
		perror("adding signalfd to epoll");
		return EXIT_FAILURE;
	}

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

	for (;;) {
		while ((rt = config_dequeue()) != NULL) {
			start_service(rt);
		}

		ret = epoll_wait(epfd, &ev, 1, -1);
		if (ret == 0)
			continue;

		if (ret < 0) {
			perror("epoll wait");
			return EXIT_FAILURE;
		}

		if (ev.data.fd == sfd) {
			handle_signal(sfd);
		}
	}

	return EXIT_SUCCESS;
}