text: /****************************************************************************
   * apps/nshlib/nsh_telnetd.c
   *
   *   Copyright (C) 2007-2013 Gregory Nutt. All rights reserved.
   *   Author: Gregory Nutt <gnutt@nuttx.org>
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   * 3. Neither the name Gregory Nutt nor the names of its contributors may be
   *    used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
   * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
   * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
   * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   *
   ****************************************************************************/
  
  /****************************************************************************
   * Included Files
   ****************************************************************************/
  
  #include <nuttx/config.h>
  
  #include <stdio.h>
  #include <unistd.h>
  #include <ctype.h>
  #include <assert.h>
  #include <debug.h>
  #include <string.h>
  
  #include <arpa/inet.h>
  
  #include <apps/netutils/telnetd.h>
  
  #include "nsh.h"
  #include "nsh_console.h"
  
  #ifdef CONFIG_NSH_TELNET
  
  /****************************************************************************
   * Pre-processor Definitions
   ****************************************************************************/
  
  #ifdef CONFIG_NSH_TELNET_LOGIN
  
  #  define TELNET_IAC              255
  #  define TELNET_WILL             251
  #  define TELNET_WONT             252
  #  define TELNET_DO               253
  #  define TELNET_DONT             254
  #  define TELNET_USE_ECHO         1
  #  define TELNET_NOTUSE_ECHO      0
  
  #endif /* CONFIG_NSH_TELNET_LOGIN */
  
  /****************************************************************************
   * Private Types
   ****************************************************************************/
  
  /****************************************************************************
   * Private Function Prototypes
   ****************************************************************************/
  
  /****************************************************************************
   * Private Data
   ****************************************************************************/
  
  /****************************************************************************
   * Public Data
   ****************************************************************************/
  
  /****************************************************************************
   * Private Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Name: nsh_telnetecho
   ****************************************************************************/
  
  #ifdef CONFIG_NSH_TELNET_LOGIN
  static void nsh_telnetecho(FAR struct console_stdio_s *pstate, uint8_t is_use)
  {
    uint8_t optbuf[4];
    optbuf[0] = TELNET_IAC;
    optbuf[1] = (is_use == TELNET_USE_ECHO) ? TELNET_WILL : TELNET_DO;
    optbuf[2] = 1;
    optbuf[3] = 0;
    fputs((char *)optbuf, pstate->cn_outstream);
    fflush(pstate->cn_outstream);
  }
  #endif
  
  /****************************************************************************
   * Name: nsh_telnettoken
   ****************************************************************************/
  
  #ifdef CONFIG_NSH_TELNET_LOGIN
  static void nsh_telnettoken(FAR struct console_stdio_s *pstate,
                              FAR char *buffer, size_t buflen)
  {
    FAR char *start;
    FAR char *endp1;
    bool quoted = false;
  
    /* Find the start of token.  Either (1) the first non-white space
     * character on the command line or (2) the character immediately after
     * a quotation mark.
     */
  
    for (start = pstate->cn_line; *start; start++)
      {
        /* Does the token open with a quotation mark */
  
        if (*start == '"')
          {
            /* Yes.. break out with start set to the character after the
             * quotation mark.
             */
  
            quoted = true;
            start++;
            break;
          }
  
        /* No, then any non-whitespace is the first character of the token */
  
        else if (!isspace(*start))
          {
            /* Break out with start set to the first character of the token */
  
            break;
          }
      }
  
    /* Find the terminating character after the token on the command line.  The
     * terminating character is either (1) the matching quotation mark, or (2)
     * any whitespace.
     */
  
    for (endp1 = start; *endp1; endp1++)
      {
        /* Did the token begin with a quotation mark? */
  
        if (quoted)
          {
            /* Yes.. then only the matching quotation mark (or end of string)
             * terminates
             */
  
            if (*endp1 == '"')
              {
                /* Break out... endp1 points to closing quotation mark */
  
                break;
              }
          }
  
        /* No.. any whitespace (or end of string) terminates */
  
        else if (isspace(*endp1))
          {
           /* Break out... endp1 points to first while space encountered */
  
            break;
          }
      }
  
    /* Replace terminating character with a NUL terminator */
  
    *endp1 = '\0';
  
    /* Copied the token into the buffer */
  
    strncpy(buffer, start, buflen);
  }
  #endif
  
  /****************************************************************************
   * Name: nsh_telnetlogin
   ****************************************************************************/
  
  #ifdef CONFIG_NSH_TELNET_LOGIN
  static int nsh_telnetlogin(FAR struct console_stdio_s *pstate)
  {
    char username[16];
    char password[16];
    uint8_t i;
  
    /* Present the NSH Telnet greeting */
  
    fputs(g_telnetgreeting, pstate->cn_outstream);
    fflush(pstate->cn_outstream);
  
    /* Loop for the configured number of retries */
  
    for (i = 0; i < CONFIG_NSH_TELNET_FAILCOUNT; i++)
      {
        /* Ask for the login username */
  
        fputs(g_userprompt, pstate->cn_outstream);
        fflush(pstate->cn_outstream);
        if (fgets(pstate->cn_line, CONFIG_NSH_LINELEN, INSTREAM(pstate)) != NULL)
          {
            /* Parse out the username */
  
            nsh_telnettoken(pstate, username, sizeof(username));
          }
  
        /* Ask for the login password */
  
        fputs(g_passwordprompt, pstate->cn_outstream);
        fflush(pstate->cn_outstream);
        nsh_telnetecho(pstate, TELNET_NOTUSE_ECHO);
        if (fgets(pstate->cn_line, CONFIG_NSH_LINELEN, INSTREAM(pstate)) != NULL)
          {
            /* Parse out the password */
  
            nsh_telnettoken(pstate, password, sizeof(password));
  
            /* Verify the username and password */
  
            if (strcmp(password, CONFIG_NSH_TELNET_PASSWORD) == 0 &&
                strcmp(username, CONFIG_NSH_TELNET_USERNAME) == 0)
              {
                fputs(g_loginsuccess, pstate->cn_outstream);
                fflush(pstate->cn_outstream);
                nsh_telnetecho(pstate, TELNET_USE_ECHO);
                return OK;
              }
            else
              {
                fputs(g_badcredentials, pstate->cn_outstream);
                fflush(pstate->cn_outstream);
              }
          }
  
        nsh_telnetecho(pstate, TELNET_USE_ECHO);
      }
  
    /* Too many failed login attempts */
  
    fputs(g_loginfailure, pstate->cn_outstream);
    fflush(pstate->cn_outstream);
    return -1;
  }
  #endif /* CONFIG_NSH_TELNET_LOGIN */
  
  /****************************************************************************
   * Public Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Name: nsh_telnetmain
   ****************************************************************************/
  
  int nsh_telnetmain(int argc, char *argv[])
  {
    FAR struct console_stdio_s *pstate = nsh_newconsole();
    DEBUGASSERT(pstate != NULL);
  
    dbg("Session [%d] Started\n", getpid());
  
    /* Login User and Password Check */
  
  #ifdef CONFIG_NSH_TELNET_LOGIN
    if (nsh_telnetlogin(pstate) != OK)
      {
        nsh_exit(&pstate->cn_vtbl, 1);
        return -1; /* nsh_exit does not return */
      }
  #endif /* CONFIG_NSH_TELNET_LOGIN */
  
    /* The following logic mostly the same as the login in nsh_session.c.  It
     * differs only in that gets() is called to get the command instead of
     * readline().
     */
  
    /* Present the NSH greeting */
  
    fputs(g_nshgreeting, pstate->cn_outstream);
    fflush(pstate->cn_outstream);
  
    /* Execute the startup script.  If standard console is also defined, then
     * we will not bother with the initscript here (although it is safe to
     * call nshinitscript multiple times).
     */
  
  #if defined(CONFIG_NSH_ROMFSETC) && !defined(CONFIG_NSH_CONSOLE)
    (void)nsh_initscript(&pstate->cn_vtbl);
  #endif
  
    /* Execute the login script */
  
  #ifdef CONFIG_NSH_ROMFSRC
    (void)nsh_loginscript(&pstate->cn_vtbl);
  #endif
  
    /* Then enter the command line parsing loop */
  
    for (;;)
      {
        /* Display the prompt string */
  
        fputs(g_nshprompt, pstate->cn_outstream);
        fflush(pstate->cn_outstream);
  
        /* Get the next line of input from the Telnet client */
  
        if (fgets(pstate->cn_line, CONFIG_NSH_LINELEN, INSTREAM(pstate)) != NULL)
          {
            /* Parse process the received Telnet command */
  
            (void)nsh_parse(&pstate->cn_vtbl, pstate->cn_line);
            fflush(pstate->cn_outstream);
          }
        else
          {
            fprintf(pstate->cn_outstream, g_fmtcmdfailed, "nsh_telnetmain",
                    "fgets", NSH_ERRNO);
            nsh_exit(&pstate->cn_vtbl, 1);
          }
      }
  
    /* Clean up */
  
    nsh_exit(&pstate->cn_vtbl, 0);
  
    /* We do not get here, but this is necessary to keep some compilers happy */
  
    return OK;
  }
  
  /****************************************************************************
   * Public Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Name: nsh_telnetstart
   *
   * Description:
   *   nsh_telnetstart() starts the Telnet daemon that will allow multiple
   *   NSH connections via Telnet.  This function returns immediately after
   *   the daemon has been started.
   *
   * Input Parameters:
   *   None.  All of the properties of the Telnet daemon are controlled by
   *   NuttX configuration setting.
   *
   * Returned Values:
   *   The task ID of the Telnet daemon was successfully started.  A negated
   *   errno value will be returned on failure.
   *
   ****************************************************************************/
  
  int nsh_telnetstart(void)
  {
    struct telnetd_config_s config;
    int ret;
  
    /* Initialize any USB tracing options that were requested.  If standard
     * console is also defined, then we will defer this step to the standard
     * console.
     */
  
  #if defined(CONFIG_NSH_USBDEV_TRACE) && !defined(CONFIG_NSH_CONSOLE)
    usbtrace_enable(TRACE_BITSET);
  #endif
  
    /* Configure the telnet daemon */
  
    config.d_port      = HTONS(CONFIG_NSH_TELNETD_PORT);
    config.d_priority  = CONFIG_NSH_TELNETD_DAEMONPRIO;
    config.d_stacksize = CONFIG_NSH_TELNETD_DAEMONSTACKSIZE;
    config.t_priority  = CONFIG_NSH_TELNETD_CLIENTPRIO;
    config.t_stacksize = CONFIG_NSH_TELNETD_CLIENTSTACKSIZE;
    config.t_entry     = nsh_telnetmain;
  
    /* Start the telnet daemon */
  
    vdbg("Starting the Telnet daemon\n");
    ret = telnetd_start(&config);
    if (ret < 0)
      {
        dbg("Failed to tart the Telnet daemon: %d\n", ret);
      }
  
    return ret;
  }
  
  #endif /* CONFIG_NSH_TELNET */
  