/*

 * iSCSI daemon event handler 

 *

 * Copyright (C) 2004 Dmitry Yusupov, Alex Aizman

 * Copyright (C) 2006 Mike Christie

 * Copyright (C) 2006 Red Hat, Inc. All rights reserved.

 * maintained by open-iscsi@googlegroups.com

 *

 * Originally based on:

 * (C) 2004 FUJITA Tomonori <tomof@acm.org>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published

 * by the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful, but

 * WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

 * General Public License for more details.

 *

 * See the file COPYING included with this distribution for more details.

 */

#include <stdlib.h>

#include <errno.h>

#include <sys/poll.h>

#include <sys/types.h>

#include <sys/wait.h>

#include <sys/signalfd.h>

#include <unistd.h>

#include "mgmt_ipc.h"

#include "iscsi_ipc.h"

#include "sysfs.h"

#include "iscsid.h"

#include "log.h"

#include "iscsi_ipc.h"

#include "actor.h"

#include "initiator.h"

#include "iscsi_err.h"

static unsigned int reap_count;

/* track pid of reload fork, while running */

static pid_t reload_pid = 0;

static void (*reload_callback)(void);

#define REAP_WAKEUP 1000 /* in millisecs */

void reap_inc(void)

{

	reap_count++;

}

/* track the reload process to be reaped, when done */

void reap_track_reload_process(pid_t reload_proc_pid, void (*reload_done_callback)(void))

{

	reload_pid = reload_proc_pid;

	reload_callback = reload_done_callback;

	reap_inc();

}

void reap_proc(void)

{

	int i, max_reaps;

	pid_t rc;

	/*

	 * We don't really need reap_count, but calling wait() all the

	 * time seems excessive.

	 */

	max_reaps = reap_count;

	for (i = 0; i < max_reaps; i++) {

		rc = waitpid(0, NULL, WNOHANG);

		if (rc > 0) {

			if (rc == reload_pid) {

				log_debug(6, "reaped reload process");

				reload_callback();

			}

			reap_count--;

			log_debug(6, "reaped pid %d, reap_count now %d",

				  (int)rc, reap_count);

		}

	}

}

static LIST_HEAD(shutdown_callbacks);

struct shutdown_callback {

	struct list_head list;

	pid_t pid;

};

int shutdown_callback(pid_t pid)

{

	struct shutdown_callback *cb;

	cb = calloc(1, sizeof(*cb));

	if (!cb)

		return ENOMEM;

	INIT_LIST_HEAD(&cb->list);

	cb->pid = pid;

	log_debug(1, "adding %d for shutdown cb", pid);

	list_add_tail(&cb->list, &shutdown_callbacks);

	return 0;

}

static void shutdown_notify_pids(void)

{

	struct shutdown_callback *cb;

	list_for_each_entry(cb, &shutdown_callbacks, list) {

		log_debug(1, "Killing %d", cb->pid);

		kill(cb->pid, SIGTERM);

	}

}

static int shutdown_wait_pids(void)

{

	struct shutdown_callback *cb, *tmp;

	list_for_each_entry_safe(cb, tmp, &shutdown_callbacks, list) {

		/*

		 * the proc reaper could clean it up, so wait for any

		 * sign that it is gone.

		 */

		if (waitpid(cb->pid, NULL, WNOHANG)) {

			log_debug(1, "%d done", cb->pid);

			list_del(&cb->list);

			free(cb);

		}

	}

	return list_empty(&shutdown_callbacks);

}

#define POLL_CTRL	0

#define POLL_IPC	1

#define POLL_ALARM	2

#define POLL_MAX	3

static volatile int event_loop_stop;

static queue_task_t *shutdown_qtask; 

void event_loop_exit(queue_task_t *qtask)

{

	shutdown_qtask = qtask;

	event_loop_stop = 1;

}

void event_loop(struct iscsi_ipc *ipc, int control_fd, int mgmt_ipc_fd)

{

	struct pollfd poll_array[POLL_MAX];

	int res, has_shutdown_children = 0;

	sigset_t sigset;

	int sig_fd;

	/* Mask off SIGALRM so we can recv it via signalfd */

	sigemptyset(&sigset);

	sigaddset(&sigset, SIGALRM);

	sigprocmask(SIG_SETMASK, &sigset, NULL);

	sig_fd = signalfd(-1, &sigset, SFD_NONBLOCK);

	if (sig_fd == -1) {

		log_error("signalfd failed: %m");

		return;

	}

	poll_array[POLL_CTRL].fd = control_fd;

	poll_array[POLL_CTRL].events = POLLIN;

	poll_array[POLL_IPC].fd = mgmt_ipc_fd;

	poll_array[POLL_IPC].events = POLLIN;

	poll_array[POLL_ALARM].fd = sig_fd;

	poll_array[POLL_ALARM].events = POLLIN;

	event_loop_stop = 0;

	while (1) {

		if (event_loop_stop) {

			if (!has_shutdown_children) {

				has_shutdown_children = 1;

				shutdown_notify_pids();

			}

			if (shutdown_wait_pids())

				break;

		}

		/* Runs actors and may set alarm for future actors */

		actor_poll();

		res = poll(poll_array, POLL_MAX, reap_count ? REAP_WAKEUP : -1);

		if (res > 0) {

			log_debug(6, "poll result %d", res);

			if (poll_array[POLL_CTRL].revents)

				ipc->ctldev_handle();

			if (poll_array[POLL_IPC].revents)

				mgmt_ipc_handle(mgmt_ipc_fd);

			if (poll_array[POLL_ALARM].revents) {

				struct signalfd_siginfo si;

				if (read(sig_fd, &si, sizeof(si)) == -1) {

					log_error("got sigfd read() error, errno (%d), "

						  "exiting", errno);

					break;

				} else {

					log_debug(1, "Poll was woken by an alarm");

				}

			}

		} else if (res < 0) {

			if (errno == EINTR) {

				log_debug(1, "event_loop interrupted");

			} else {

				log_error("got poll() error (%d), errno (%d), "

					  "exiting", res, errno);

				break;

			}

		}

		reap_proc();

		/*

		 * flush sysfs cache since kernel objs may

		 * have changed as a result of handling op

		 */

		sysfs_cleanup();

	}

	if (shutdown_qtask)

		mgmt_ipc_write_rsp(shutdown_qtask, ISCSI_SUCCESS);

	close(sig_fd);

	sigprocmask(SIG_UNBLOCK, &sigset, NULL);

}