target: DCC / target message backoff algorithm

[openocd.git] / src / server / server.c

/***************************************************************************
 *   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.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, 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 = NULL;

/* shutdown_openocd == 1: exit the main event loop, and quit the debugger */
static int shutdown_openocd = 0;

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. */
                retval = 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);
                if ((retval = service->new_connection(c)) != ERROR_OK)
                {
                        close_socket(c->fd);
                        LOG_ERROR("attempted '%s' connection rejected", service->name);
                        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);
                if ((retval = service->new_connection(c)) != ERROR_OK)
                {
                        LOG_ERROR("attempted '%s' connection rejected", service->name);
                        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);
                if ((retval = service->new_connection(c)) != ERROR_OK)
                {
                        LOG_ERROR("attempted '%s' connection rejected", service->name);
                        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;

                if ((c->fd = socket(AF_INET, SOCK_STREAM, 0)) == -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((void *)c->name);

                if (c->type == CONNECTION_PIPE)
                {
                        if (c->fd != -1)
                                close(c->fd);
                }
                if (c->port)
                        free((void *)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)
                                        {
                                                if ((retval = service->input(c)) != ERROR_OK)
                                                {
                                                        struct connection *next = c->next;
                                                        if (service->type == CONNECTION_PIPE)
                                                        {
                                                                /* 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,
                .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);
}

SERVER_PORT_COMMAND()
{
        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_INVALID_ARGUMENTS;
        }
        return ERROR_OK;
}

SERVER_PIPE_COMMAND()
{
        switch (CMD_ARGC) {
        case 0:
                command_print(CMD_CTX, "%s", *out);
                break;
        case 1:
        {
                const char * t = strdup(CMD_ARGV[0]);
                free((void *)*out);
                *out = t;
                break;
        }
        default:
                return ERROR_INVALID_ARGUMENTS;
        }
        return ERROR_OK;
}