/***************************************************************************
 *   Copyright (C) 2005 by Dominic Rath                                    *
 *   Dominic.Rath@gmx.de                                                   *
 *                                                                         *
 *   Copyright (C) 2007-2010 Øyvind Harboe                                 *
 *   oyvind.harboe@zylin.com                                               *
 *                                                                         *
 *   Copyright (C) 2008 by Spencer Oliver                                  *
 *   spen@spen-soft.co.uk                                                  *
 *                                                                         *
 *   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.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.           *
 ***************************************************************************/

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "server.h"
#include <target/target.h>
#include <target/target_request.h>
#include "openocd.h"
#include "tcl_server.h"
#include "telnet_server.h"

#include <signal.h>

#ifndef _WIN32
#include <netinet/tcp.h>
#endif

static struct service *services;

/* shutdown_openocd == 1: exit the main event loop, and quit the debugger */
static int shutdown_openocd;

static int add_connection(struct service *service, struct command_context *cmd_ctx)
{
	socklen_t address_size;
	struct connection *c, **p;
	int retval;
	int flag = 1;

	c = malloc(sizeof(struct connection));
	c->fd = -1;
	c->fd_out = -1;
	memset(&c->sin, 0, sizeof(c->sin));
	c->cmd_ctx = copy_command_context(cmd_ctx);
	c->service = service;
	c->input_pending = 0;
	c->priv = NULL;
	c->next = NULL;

	if (service->type == CONNECTION_TCP) {
		address_size = sizeof(c->sin);

		c->fd = accept(service->fd, (struct sockaddr *)&service->sin, &address_size);
		c->fd_out = c->fd;

		/* This increases performance dramatically for e.g. GDB load which
		 * does not have a sliding window protocol.
		 *
		 * Ignore errors from this fn as it probably just means less performance
		 */
		setsockopt(c->fd,	/* socket affected */
			IPPROTO_TCP,			/* set option at TCP level */
			TCP_NODELAY,			/* name of option */
			(char *)&flag,			/* the cast is historical cruft */
			sizeof(int));			/* length of option value */

		LOG_INFO("accepting '%s' connection from %s", service->name, service->port);
		retval = service->new_connection(c);
		if (retval != ERROR_OK) {
			close_socket(c->fd);
			LOG_ERROR("attempted '%s' connection rejected", service->name);
			command_done(c->cmd_ctx);
			free(c);
			return retval;
		}
	} else if (service->type == CONNECTION_STDINOUT) {
		c->fd = service->fd;
		c->fd_out = fileno(stdout);

#ifdef _WIN32
		/* we are using stdin/out so ignore ctrl-c under windoze */
		SetConsoleCtrlHandler(NULL, TRUE);
#endif

		/* do not check for new connections again on stdin */
		service->fd = -1;

		LOG_INFO("accepting '%s' connection from pipe", service->name);
		retval = service->new_connection(c);
		if (retval != ERROR_OK) {
			LOG_ERROR("attempted '%s' connection rejected", service->name);
			command_done(c->cmd_ctx);
			free(c);
			return retval;
		}
	} else if (service->type == CONNECTION_PIPE) {
		c->fd = service->fd;
		/* do not check for new connections again on stdin */
		service->fd = -1;

		char *out_file = alloc_printf("%so", service->port);
		c->fd_out = open(out_file, O_WRONLY);
		free(out_file);
		if (c->fd_out == -1) {
			LOG_ERROR("could not open %s", service->port);
			exit(1);
		}

		LOG_INFO("accepting '%s' connection from pipe %s", service->name, service->port);
		retval = service->new_connection(c);
		if (retval != ERROR_OK) {
			LOG_ERROR("attempted '%s' connection rejected", service->name);
			command_done(c->cmd_ctx);
			free(c);
			return retval;
		}
	}

	/* add to the end of linked list */
	for (p = &service->connections; *p; p = &(*p)->next)
		;
	*p = c;

	service->max_connections--;

	return ERROR_OK;
}

static int remove_connection(struct service *service, struct connection *connection)
{
	struct connection **p = &service->connections;
	struct connection *c;

	/* find connection */
	while ((c = *p)) {
		if (c->fd == connection->fd) {
			service->connection_closed(c);
			if (service->type == CONNECTION_TCP)
				close_socket(c->fd);
			else if (service->type == CONNECTION_PIPE) {
				/* The service will listen to the pipe again */
				c->service->fd = c->fd;
			}

			command_done(c->cmd_ctx);

			/* delete connection */
			*p = c->next;
			free(c);

			service->max_connections++;
			break;
		}

		/* redirect p to next list pointer */
		p = &(*p)->next;
	}

	return ERROR_OK;
}

/* FIX! make service return error instead of invoking exit() */
int add_service(char *name,
	const char *port,
	int max_connections,
	new_connection_handler_t new_connection_handler,
	input_handler_t input_handler,
	connection_closed_handler_t connection_closed_handler,
	void *priv)
{
	struct service *c, **p;
	int so_reuseaddr_option = 1;

	c = malloc(sizeof(struct service));

	c->name = strdup(name);
	c->port = strdup(port);
	c->max_connections = 1;	/* Only TCP/IP ports can support more than one connection */
	c->fd = -1;
	c->connections = NULL;
	c->new_connection = new_connection_handler;
	c->input = input_handler;
	c->connection_closed = connection_closed_handler;
	c->priv = priv;
	c->next = NULL;
	long portnumber;
	if (strcmp(c->port, "pipe") == 0)
		c->type = CONNECTION_STDINOUT;
	else {
		char *end;
		portnumber = strtol(c->port, &end, 0);
		if (!*end && (parse_long(c->port, &portnumber) == ERROR_OK)) {
			c->portnumber = portnumber;
			c->type = CONNECTION_TCP;
		} else
			c->type = CONNECTION_PIPE;
	}

	if (c->type == CONNECTION_TCP) {
		c->max_connections = max_connections;

		c->fd = socket(AF_INET, SOCK_STREAM, 0);
		if (c->fd == -1) {
			LOG_ERROR("error creating socket: %s", strerror(errno));
			exit(-1);
		}

		setsockopt(c->fd,
			SOL_SOCKET,
			SO_REUSEADDR,
			(void *)&so_reuseaddr_option,
			sizeof(int));

		socket_nonblock(c->fd);

		memset(&c->sin, 0, sizeof(c->sin));
		c->sin.sin_family = AF_INET;
		c->sin.sin_addr.s_addr = INADDR_ANY;
		c->sin.sin_port = htons(c->portnumber);

		if (bind(c->fd, (struct sockaddr *)&c->sin, sizeof(c->sin)) == -1) {
			LOG_ERROR("couldn't bind to socket: %s", strerror(errno));
			exit(-1);
		}

#ifndef _WIN32
		int segsize = 65536;
		setsockopt(c->fd, IPPROTO_TCP, TCP_MAXSEG,  &segsize, sizeof(int));
#endif
		int window_size = 128 * 1024;

		/* These setsockopt()s must happen before the listen() */

		setsockopt(c->fd, SOL_SOCKET, SO_SNDBUF,
			(char *)&window_size, sizeof(window_size));
		setsockopt(c->fd, SOL_SOCKET, SO_RCVBUF,
			(char *)&window_size, sizeof(window_size));

		if (listen(c->fd, 1) == -1) {
			LOG_ERROR("couldn't listen on socket: %s", strerror(errno));
			exit(-1);
		}
	} else if (c->type == CONNECTION_STDINOUT) {
		c->fd = fileno(stdin);

#ifdef _WIN32
		/* for win32 set stdin/stdout to binary mode */
		if (_setmode(_fileno(stdout), _O_BINARY) < 0)
			LOG_WARNING("cannot change stdout mode to binary");
		if (_setmode(_fileno(stdin), _O_BINARY) < 0)
			LOG_WARNING("cannot change stdin mode to binary");
		if (_setmode(_fileno(stderr), _O_BINARY) < 0)
			LOG_WARNING("cannot change stderr mode to binary");
#else
		socket_nonblock(c->fd);
#endif
	} else if (c->type == CONNECTION_PIPE) {
#ifdef _WIN32
		/* we currenty do not support named pipes under win32
		 * so exit openocd for now */
		LOG_ERROR("Named pipes currently not supported under this os");
		exit(1);
#else
		/* Pipe we're reading from */
		c->fd = open(c->port, O_RDONLY | O_NONBLOCK);
		if (c->fd == -1) {
			LOG_ERROR("could not open %s", c->port);
			exit(1);
		}
#endif
	}

	/* add to the end of linked list */
	for (p = &services; *p; p = &(*p)->next)
		;
	*p = c;

	return ERROR_OK;
}

static int remove_services(void)
{
	struct service *c = services;

	/* loop service */
	while (c) {
		struct service *next = c->next;

		if (c->name)
			free(c->name);

		if (c->type == CONNECTION_PIPE) {
			if (c->fd != -1)
				close(c->fd);
		}
		if (c->port)
			free(c->port);

		if (c->priv)
			free(c->priv);

		/* delete service */
		free(c);

		/* remember the last service for unlinking */
		c = next;
	}

	services = NULL;

	return ERROR_OK;
}

int server_loop(struct command_context *command_context)
{
	struct service *service;

	bool poll_ok = true;

	/* used in select() */
	fd_set read_fds;
	int fd_max;

	/* used in accept() */
	int retval;

#ifndef _WIN32
	if (signal(SIGPIPE, SIG_IGN) == SIG_ERR)
		LOG_ERROR("couldn't set SIGPIPE to SIG_IGN");
#endif

	while (!shutdown_openocd) {
		/* monitor sockets for activity */
		fd_max = 0;
		FD_ZERO(&read_fds);

		/* add service and connection fds to read_fds */
		for (service = services; service; service = service->next) {
			if (service->fd != -1) {
				/* listen for new connections */
				FD_SET(service->fd, &read_fds);

				if (service->fd > fd_max)
					fd_max = service->fd;
			}

			if (service->connections) {
				struct connection *c;

				for (c = service->connections; c; c = c->next) {
					/* check for activity on the connection */
					FD_SET(c->fd, &read_fds);
					if (c->fd > fd_max)
						fd_max = c->fd;
				}
			}
		}

		struct timeval tv;
		tv.tv_sec = 0;
		if (poll_ok) {
			/* we're just polling this iteration, this is faster on embedded
			 * hosts */
			tv.tv_usec = 0;
			retval = socket_select(fd_max + 1, &read_fds, NULL, NULL, &tv);
		} else {
			/* Every 100ms */
			tv.tv_usec = 100000;
			/* Only while we're sleeping we'll let others run */
			openocd_sleep_prelude();
			kept_alive();
			retval = socket_select(fd_max + 1, &read_fds, NULL, NULL, &tv);
			openocd_sleep_postlude();
		}

		if (retval == -1) {
#ifdef _WIN32

			errno = WSAGetLastError();

			if (errno == WSAEINTR)
				FD_ZERO(&read_fds);
			else {
				LOG_ERROR("error during select: %s", strerror(errno));
				exit(-1);
			}
#else

			if (errno == EINTR)
				FD_ZERO(&read_fds);
			else {
				LOG_ERROR("error during select: %s", strerror(errno));
				exit(-1);
			}
#endif
		}

		if (retval == 0) {
			/* We only execute these callbacks when there was nothing to do or we timed
			 *out */
			target_call_timer_callbacks();
			process_jim_events(command_context);

			FD_ZERO(&read_fds);	/* eCos leaves read_fds unchanged in this case!  */

			/* We timed out/there was nothing to do, timeout rather than poll next time
			 **/
			poll_ok = false;
		} else {
			/* There was something to do, next time we'll just poll */
			poll_ok = true;
		}

		/* This is a simple back-off algorithm where we immediately
		 * re-poll if we did something this time around.
		 *
		 * This greatly improves performance of DCC.
		 */
		poll_ok = poll_ok || target_got_message();

		for (service = services; service; service = service->next) {
			/* handle new connections on listeners */
			if ((service->fd != -1)
			    && (FD_ISSET(service->fd, &read_fds))) {
				if (service->max_connections > 0)
					add_connection(service, command_context);
				else {
					if (service->type == CONNECTION_TCP) {
						struct sockaddr_in sin;
						socklen_t address_size = sizeof(sin);
						int tmp_fd;
						tmp_fd = accept(service->fd,
								(struct sockaddr *)&service->sin,
								&address_size);
						close_socket(tmp_fd);
					}
					LOG_INFO(
						"rejected '%s' connection, no more connections allowed",
						service->name);
				}
			}

			/* handle activity on connections */
			if (service->connections) {
				struct connection *c;

				for (c = service->connections; c; ) {
					if ((FD_ISSET(c->fd, &read_fds)) || c->input_pending) {
						retval = service->input(c);
						if (retval != ERROR_OK) {
							struct connection *next = c->next;
							if (service->type == CONNECTION_PIPE ||
									service->type == CONNECTION_STDINOUT) {
								/* if connection uses a pipe then
								 * shutdown openocd on error */
								shutdown_openocd = 1;
							}
							remove_connection(service, c);
							LOG_INFO("dropped '%s' connection",
								service->name);
							c = next;
							continue;
						}
					}
					c = c->next;
				}
			}
		}

#ifdef _WIN32
		MSG msg;
		while (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE)) {
			if (msg.message == WM_QUIT)
				shutdown_openocd = 1;
		}
#endif
	}

	return ERROR_OK;
}

#ifdef _WIN32
BOOL WINAPI ControlHandler(DWORD dwCtrlType)
{
	shutdown_openocd = 1;
	return TRUE;
}

void sig_handler(int sig)
{
	shutdown_openocd = 1;
}
#endif

int server_preinit(void)
{
	/* this currently only calls WSAStartup on native win32 systems
	 * before any socket operations are performed.
	 * This is an issue if you call init in your config script */

#ifdef _WIN32
	WORD wVersionRequested;
	WSADATA wsaData;

	wVersionRequested = MAKEWORD(2, 2);

	if (WSAStartup(wVersionRequested, &wsaData) != 0) {
		LOG_ERROR("Failed to Open Winsock");
		exit(-1);
	}

	/* register ctrl-c handler */
	SetConsoleCtrlHandler(ControlHandler, TRUE);

	signal(SIGINT, sig_handler);
	signal(SIGTERM, sig_handler);
	signal(SIGBREAK, sig_handler);
	signal(SIGABRT, sig_handler);
#endif

	return ERROR_OK;
}

int server_init(struct command_context *cmd_ctx)
{
	int ret = tcl_init();
	if (ERROR_OK != ret)
		return ret;

	return telnet_init("Open On-Chip Debugger");
}

int server_quit(void)
{
	remove_services();

#ifdef _WIN32
	WSACleanup();
	SetConsoleCtrlHandler(ControlHandler, FALSE);
#endif

	return ERROR_OK;
}

int connection_write(struct connection *connection, const void *data, int len)
{
	if (len == 0) {
		/* successful no-op. Sockets and pipes behave differently here... */
		return 0;
	}
	if (connection->service->type == CONNECTION_TCP)
		return write_socket(connection->fd_out, data, len);
	else
		return write(connection->fd_out, data, len);
}

int connection_read(struct connection *connection, void *data, int len)
{
	if (connection->service->type == CONNECTION_TCP)
		return read_socket(connection->fd, data, len);
	else
		return read(connection->fd, data, len);
}

/* tell the server we want to shut down */
COMMAND_HANDLER(handle_shutdown_command)
{
	LOG_USER("shutdown command invoked");

	shutdown_openocd = 1;

	return ERROR_OK;
}

static const struct command_registration server_command_handlers[] = {
	{
		.name = "shutdown",
		.handler = &handle_shutdown_command,
		.mode = COMMAND_ANY,
		.usage = "",
		.help = "shut the server down",
	},
	COMMAND_REGISTRATION_DONE
};

int server_register_commands(struct command_context *cmd_ctx)
{
	int retval = telnet_register_commands(cmd_ctx);
	if (ERROR_OK != retval)
		return retval;

	retval = tcl_register_commands(cmd_ctx);
	if (ERROR_OK != retval)
		return retval;

	return register_commands(cmd_ctx, NULL, server_command_handlers);
}

COMMAND_HELPER(server_port_command, unsigned short *out)
{
	switch (CMD_ARGC) {
		case 0:
			command_print(CMD_CTX, "%d", *out);
			break;
		case 1:
		{
			uint16_t port;
			COMMAND_PARSE_NUMBER(u16, CMD_ARGV[0], port);
			*out = port;
			break;
		}
		default:
			return ERROR_COMMAND_SYNTAX_ERROR;
	}
	return ERROR_OK;
}

COMMAND_HELPER(server_pipe_command, char **out)
{
	switch (CMD_ARGC) {
		case 0:
			command_print(CMD_CTX, "%s", *out);
			break;
		case 1:
		{
			if (CMD_CTX->mode == COMMAND_EXEC) {
				LOG_WARNING("unable to change server port after init");
				return ERROR_COMMAND_ARGUMENT_INVALID;
			}
			free(*out);
			*out = strdup(CMD_ARGV[0]);
			break;
		}
		default:
			return ERROR_COMMAND_SYNTAX_ERROR;
	}
	return ERROR_OK;
}
