telnet.c

VLC Player Source Code

/*****************************************************************************
 * telnet.c: VLM interface plugin
 *****************************************************************************
 * Copyright (C) 2000-2006 the VideoLAN team
 * $Id: cffbdd849cf17b9b26effb8772e972acfd8fd3b2 $
 *
 * Authors: Simon Latapie <[e-mail]>
 *          Laurent Aimar <[e-mail]>
 *
 * 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.
 *****************************************************************************/

/*****************************************************************************
 * Preamble
 *****************************************************************************/

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

#include <vlc_common.h>
#include <vlc_plugin.h>
#include <vlc_interface.h>
#include <vlc_input.h>

#include <stdbool.h>
#include <sys/stat.h>

#include <errno.h>
#include <fcntl.h>

#ifdef HAVE_SYS_TIME_H
#    include <sys/time.h>
#endif

#ifdef HAVE_UNISTD_H
#   include <unistd.h>
#endif
#ifdef HAVE_POLL
#   include <poll.h>
#endif

#include <vlc_network.h>
#include <vlc_url.h>
#include <vlc_vlm.h>

#define READ_MODE_PWD 1
#define READ_MODE_CMD 2
#define WRITE_MODE_PWD 3 // when we write the word "Password:"
#define WRITE_MODE_CMD 4

/* telnet commands */
#define TEL_WILL    251
#define TEL_WONT    252
#define TEL_DO      253
#define TEL_DONT    254
#define TEL_IAC     255
#define TEL_ECHO    1

/*****************************************************************************
 * Module descriptor
 *****************************************************************************/
static int  Open ( vlc_object_t * );
static void Close( vlc_object_t * );

#define TELNETHOST_TEXT N_( "Host" )
#define TELNETHOST_LONGTEXT N_( "This is the host on which the " \
    "interface will listen. It defaults to all network interfaces (0.0.0.0)." \
    " If you want this interface to be available only on the local " \
    "machine, enter \"127.0.0.1\"." )
#define TELNETPORT_TEXT N_( "Port" )
#define TELNETPORT_LONGTEXT N_( "This is the TCP port on which this " \
    "interface will listen. It defaults to 4212." )
#define TELNETPORT_DEFAULT 4212
#define TELNETPWD_TEXT N_( "Password" )
#define TELNETPWD_LONGTEXT N_( "A single administration password is used " \
    "to protect this interface. The default value is \"admin\"." )
#define TELNETPWD_DEFAULT "admin"

vlc_module_begin();
    set_shortname( "Telnet" );
    set_category( CAT_INTERFACE );
    set_subcategory( SUBCAT_INTERFACE_CONTROL );
    add_string( "telnet-host", "", NULL, TELNETHOST_TEXT,
                 TELNETHOST_LONGTEXT, true );
    add_integer( "telnet-port", TELNETPORT_DEFAULT, NULL, TELNETPORT_TEXT,
                 TELNETPORT_LONGTEXT, true );
    add_password( "telnet-password", TELNETPWD_DEFAULT, NULL, TELNETPWD_TEXT,
                TELNETPWD_LONGTEXT, true );
    set_description( N_("VLM remote control interface") );
    add_category_hint( "VLM", NULL, false );
    set_capability( "interface", 0 );
    set_callbacks( Open , Close );
vlc_module_end();

/*****************************************************************************
 * Local prototypes.
 *****************************************************************************/
static void Run( intf_thread_t * );

typedef struct
{
    int        i_mode; /* read or write */
    int        fd;
    char       buffer_read[1000]; // 1000 byte per command should be sufficient
    char      *buffer_write;
    char      *p_buffer_read;
    char      *p_buffer_write; // the position in the buffer
    int        i_buffer_write; // the number of byte we still have to send
    int        i_tel_cmd; // for specific telnet commands

} telnet_client_t;

static char *MessageToString( vlm_message_t *, int );
static void Write_message( telnet_client_t *, vlm_message_t *, const char *, int );

struct intf_sys_t
{
   telnet_client_t **clients;
   int             i_clients;
   int             *pi_fd;
   vlm_t           *mediatheque;
};

/*
 * getPort: Decide which port to use. There are two possibilities to
 * specify a port: integrated in the --telnet-host option with :PORT
 * or using the --telnet-port option. The --telnet-port option has
 * precedence.
 * This code relies upon the fact the url.i_port is 0 if the :PORT
 * option is missing from --telnet-host.
 */
static int getPort(intf_thread_t *p_intf, const vlc_url_t *url, int i_port)
{
    if (i_port == TELNETPORT_DEFAULT && url->i_port != 0)
        i_port = url->i_port;
    if (url->i_port != 0 && url->i_port != i_port)
        // Print error if two different ports have been specified
        msg_Warn( p_intf, "ignoring port %d (using %d)", url->i_port, i_port );
    return i_port;
}

/*****************************************************************************
 * Open: initialize dummy interface
 *****************************************************************************/
static int Open( vlc_object_t *p_this )
{
    intf_thread_t *p_intf = (intf_thread_t*) p_this;
    vlm_t *mediatheque;
    char *psz_address;
    vlc_url_t url;
    int i_telnetport;

    if( !(mediatheque = vlm_New( p_intf )) )
    {
        msg_Err( p_intf, "cannot start VLM" );
        return VLC_EGENERIC;
    }

    msg_Info( p_intf, "using the VLM interface plugin..." );

    i_telnetport = config_GetInt( p_intf, "telnet-port" );
    psz_address  = config_GetPsz( p_intf, "telnet-host" );

    vlc_UrlParse(&url, psz_address, 0);
    free( psz_address );

    // There might be two ports given, resolve any potentially
    // conflict
    url.i_port = getPort(p_intf, &url, i_telnetport);

    p_intf->p_sys = malloc( sizeof( intf_sys_t ) );
    if( !p_intf->p_sys )
    {
        vlm_Delete( mediatheque );
        vlc_UrlClean( &url );
        return VLC_ENOMEM;
    }
    if( ( p_intf->p_sys->pi_fd = net_ListenTCP( p_intf, url.psz_host, url.i_port ) ) == NULL )
    {
        msg_Err( p_intf, "cannot listen for telnet" );
        vlm_Delete( mediatheque );
        vlc_UrlClean( &url );
        free( p_intf->p_sys );
        return VLC_EGENERIC;
    }
    msg_Info( p_intf,
              "telnet interface started on interface %s %d",
              url.psz_host, url.i_port );

    p_intf->p_sys->i_clients   = 0;
    p_intf->p_sys->clients     = NULL;
    p_intf->p_sys->mediatheque = mediatheque;
    p_intf->pf_run = Run;

    vlc_UrlClean( &url );
    return VLC_SUCCESS;
}

/*****************************************************************************
 * Close:
 *****************************************************************************/
static void Close( vlc_object_t *p_this )
{
    intf_thread_t *p_intf = (intf_thread_t*)p_this;
    intf_sys_t    *p_sys  = p_intf->p_sys;
    int i;

    for( i = 0; i < p_sys->i_clients; i++ )
    {
        telnet_client_t *cl = p_sys->clients[i];
        net_Close( cl->fd );
        free( cl->buffer_write );
        free( cl );
    }
    free( p_sys->clients );

    net_ListenClose( p_sys->pi_fd );

    vlm_Delete( p_sys->mediatheque );

    free( p_sys );
}

/*****************************************************************************
 * Run: main loop
 *****************************************************************************/
static void Run( intf_thread_t *p_intf )
{
    intf_sys_t     *p_sys = p_intf->p_sys;
    char           *psz_password;
    unsigned        nlisten = 0;

    for (const int *pfd = p_sys->pi_fd; *pfd != -1; pfd++)
        nlisten++; /* How many listening sockets do we have? */

    psz_password = config_GetPsz( p_intf, "telnet-password" );

    while( !intf_ShouldDie( p_intf ) )
    {
        unsigned ncli = p_sys->i_clients;
        struct pollfd ufd[ncli + nlisten];

        for (unsigned i = 0; i < ncli; i++)
        {
            telnet_client_t *cl = p_sys->clients[i];

            ufd[i].fd = cl->fd;
            if( (cl->i_mode == WRITE_MODE_PWD) || (cl->i_mode == WRITE_MODE_CMD) )
                ufd[i].events = POLLOUT;
            else
                ufd[i].events = POLLIN;
            ufd[i].revents = 0;
        }

        for (unsigned i = 0; i < nlisten; i++)
        {
            ufd[ncli + i].fd = p_sys->pi_fd[i];
            ufd[ncli + i].events = POLLIN;
            ufd[ncli + i].revents = 0;
        }

        /* FIXME: arbitrary tick */
        switch (poll (ufd, sizeof (ufd) / sizeof (ufd[0]), 500))
        {
            case -1:
                if (net_errno != EINTR)
                {
                    msg_Err (p_intf, "network poll error");
                    msleep (1000);
                    continue;
                }
            case 0:
                continue;
        }

        /* check if there is something to do with the socket */
        for (unsigned i = 0; i < ncli; i++)
        {
            telnet_client_t *cl = p_sys->clients[i];

            if (ufd[i].revents & (POLLERR|POLLHUP))
            {
            drop:
                net_Close( cl->fd );
                TAB_REMOVE( p_intf->p_sys->i_clients ,
                            p_intf->p_sys->clients , cl );
                free( cl );