telnetsrv.c

/*
 * Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The OpenAirInterface Software Alliance licenses this file to You under
 * the OAI Public License, Version 1.1  (the "License"); you may not use this file
 * except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.openairinterface.org/?page_id=698
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *-------------------------------------------------------------------------------
 * For more information about the OpenAirInterface (OAI) Software Alliance:
 *      contact@openairinterface.org
 */

/*! \file common/utils/telnetsrv/telnetsrv.c
 * \brief: implementation of a telnet server
 * \author Francois TABURET
 * \date 2017
 * \version 0.1
 * \company NOKIA BellLabs France
 * \email: francois.taburet@nokia-bell-labs.com
 * \note
 * \warning
 */
#define _GNU_SOURCE
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <pthread.h>
#include "telnetsrv.h"
#include <string.h>
#include <stdarg.h>
#include <unistd.h>
#include <fcntl.h>
#include <dlfcn.h>
#include <sys/time.h>
#include <sys/resource.h>
#include "common/utils/load_module_shlib.h"
#include "common/config/config_userapi.h"
#include <readline/history.h>


#include "telnetsrv_phycmd.h"
#include "telnetsrv_proccmd.h"
static char *telnet_defstatmod[] = {"softmodem","phy","loader","measur"};
static telnetsrv_params_t telnetparams;
#define TELNETSRV_LISTENADDR 0
#define TELNETSRV_LISTENPORT 1
#define TELNETSRV_PRIORITY   2
#define TELNETSRV_DEBUG      3
#define TELNETSRV_LOOPC      4
#define TELNETSRV_LOOPD      5
#define TELNETSRV_HISFILE    6
#define TELNETSRV_HISSIZE    7
#define TELNETSRV_PHYBSIZE   8
#define TELNETSRV_STATICMOD  9
#define TELNETSRV_SHRMOD     10

paramdef_t telnetoptions[] = {
  /*--------------------------------------------------------------------------------------------------------------------------------------------------------------------*/
  /*                                            configuration parameters for telnet utility                                                                             */
  /*   optname                     helpstr                paramflags           XXXptr                               defXXXval               type                 numelt */
  /*--------------------------------------------------------------------------------------------------------------------------------------------------------------------*/
  {"listenaddr",    "<listen ip address>\n",         0,                 uptr:&telnetparams.listenaddr,        defstrval:"0.0.0.0",            TYPE_IPV4ADDR,  0 },
  {"listenport",    "<local port>\n",                0,                 uptr:&(telnetparams.listenport),      defuintval:9090,                TYPE_UINT,      0 },
  {"priority",      "<scheduling policy (0-99)\n",   0,                 iptr:&telnetparams.priority,          defuintval:0,                   TYPE_INT,       0 },
  {"debug",         "<debug level>\n",               0,                 uptr:NULL,                            defuintval:0,                   TYPE_UINT,      0 },
  {"loopcount",     "<loop command iterations>\n",   0,                 uptr:&(telnetparams.loopcount),       defuintval:10,                  TYPE_UINT,      0 },
  {"loopdelay",     "<loop command delay (ms)>\n",   0,                 uptr:&(telnetparams.loopdelay),       defuintval:5000,                TYPE_UINT,      0 },
  {"histfile",      "<history file name>\n",         PARAMFLAG_NOFREE,  strptr:&(telnetparams.histfile),      defstrval:"oaitelnet.history",  TYPE_STRING,    0 },
  {"histsize",      "<history sizes>\n",             0,                 iptr:&(telnetparams.histsize),        defuintval:50,                  TYPE_INT,       0 },
  {"phypbsize",     "<phy dump buff size (bytes)>\n",0,                 uptr:&(telnetparams.phyprntbuff_size),defuintval:65000,               TYPE_UINT,      0 },
  {"staticmod",     "<static modules selection>\n",  0,                 strlistptr:NULL,                      defstrlistval:telnet_defstatmod,TYPE_STRINGLIST,(sizeof(telnet_defstatmod)/sizeof(char *))},
  {"shrmod",        "<dynamic modules selection>\n", 0,                 strlistptr:NULL,                      defstrlistval:NULL,TYPE_STRINGLIST,0 }
};

int get_phybsize(void) {
  return telnetparams.phyprntbuff_size;
};
int add_telnetcmd(char *modulename,telnetshell_vardef_t *var, telnetshell_cmddef_t *cmd );
int setoutput(char *buff, int debug, telnet_printfunc_t prnt);
int setparam(char *buff, int debug, telnet_printfunc_t prnt);
int history_cmd(char *buff, int debug, telnet_printfunc_t prnt);

telnetshell_vardef_t telnet_vardef[] = {
  {"debug",TELNET_VARTYPE_INT32,&telnetparams.telnetdbg},
  {"prio",TELNET_VARTYPE_INT32,&telnetparams.priority},
  {"loopc",TELNET_VARTYPE_INT32,&telnetparams.loopcount},
  {"loopd",TELNET_VARTYPE_INT32,&telnetparams.loopdelay},
  {"phypb",TELNET_VARTYPE_INT32,&telnetparams.phyprntbuff_size},
  {"hsize",TELNET_VARTYPE_INT32,&telnetparams.histsize},
  {"hfile",TELNET_VARTYPE_STRING,&telnetparams.histfile},
  {"",0,NULL}
};

telnetshell_cmddef_t  telnet_cmdarray[] = {
  {"redirlog","[here,file,off]",setoutput},
  {"param","[prio]",setparam},
  {"history","[list,reset]",history_cmd},
  {"","",NULL},
};


void client_printf(const char *message, ...) {
  va_list va_args;
  va_start(va_args, message);

  if (telnetparams.new_socket > 0) {
    vsnprintf(telnetparams.msgbuff,sizeof(telnetparams.msgbuff)-1,message, va_args);
    send(telnetparams.new_socket,telnetparams.msgbuff, strlen(telnetparams.msgbuff), MSG_NOSIGNAL);
  } else {
    vprintf(message, va_args);
  }

  va_end(va_args);
  return ;
}

#define NICE_MAX 19
#define NICE_MIN -20
void set_sched(pthread_t tid, int pid, int priority) {
  int rt;
  struct sched_param schedp;
  int policy;
  char strpolicy[10];

  //sched_get_priority_max(SCHED_FIFO)
  if (priority < NICE_MIN) {
    policy=SCHED_FIFO;
    sprintf(strpolicy,"%s","fifo");
    schedp.sched_priority= NICE_MIN - priority ;

    if (   (schedp.sched_priority < sched_get_priority_min(SCHED_FIFO)) ||
           (schedp.sched_priority > sched_get_priority_max(SCHED_FIFO)) ) {
      client_printf("Error: %i invalid prio, should be %i to %i, \n",
                    priority, NICE_MIN -sched_get_priority_min(SCHED_FIFO),
                    NICE_MIN - sched_get_priority_max(SCHED_FIFO) );
    }
  } else if (priority > NICE_MAX) {
    policy=SCHED_IDLE;
    sprintf(strpolicy,"%s","idle");
    schedp.sched_priority=0;
  } else {
    policy=SCHED_OTHER;
    sprintf(strpolicy,"%s","other");
    schedp.sched_priority=0;
  }

  if( tid != 0) {
    rt = pthread_setschedparam(tid, policy, &schedp);
  } else if(pid > 0)  {
    rt = sched_setscheduler( pid, policy,&schedp);
  } else {
    rt= -1;
    client_printf("Error: no pid or tid specified\n");
  }

  if (rt != 0) {
    client_printf("Error %i: %s modifying sched param to %s:%i, \n",
                  errno,strerror(errno),strpolicy,schedp.sched_priority);
  } else  {
    client_printf("policy set to %s, priority %i\n",strpolicy,schedp.sched_priority);

    if ( policy==SCHED_OTHER) {
      rt = getpriority(PRIO_PROCESS,tid);

      if (rt != -1) {
        rt = setpriority(PRIO_PROCESS,tid,priority);

        if (rt < 0) {
          client_printf("Error %i: %s trying to set nice value of thread %u to %i\n",
                        errno,strerror(errno),tid,priority);
        }
      } else {
        client_printf("Error %i: %s trying to get nice value of thread %u \n",
                      errno,strerror(errno),tid);
      }
    }
  }

  if ( policy == SCHED_OTHER) {
    if ( tid > 0 && tid != pthread_self()) {
      client_printf("setting nice value using a thread id not implemented....\n");
    } else if (pid > 0) {
      errno=0;
      rt = setpriority(PRIO_PROCESS,pid,priority);

      if (rt != 0) {
        client_printf("Error %i: %s calling setpriority, \n",errno,strerror(errno));
      } else {
        client_printf("nice value set to %i\n",priority);
      }
    }
  }
}

void set_affinity(pthread_t tid, int pid, int coreid) {
  cpu_set_t cpuset;
  int rt;
  CPU_ZERO(&cpuset);
  CPU_SET(coreid, &cpuset);

  if (tid > 0) {
    rt = pthread_setaffinity_np((pthread_t)tid, sizeof(cpu_set_t), &cpuset);
  } else if (pid > 0) {
    rt = sched_setaffinity((pid_t)pid, sizeof(cpu_set_t), &cpuset);
  } else {
    rt= -1;
  }

  if (rt != 0) {
    client_printf("Error %i: %s calling , xxx_setaffinity...\n",errno,strerror(errno));
  } else {
    client_printf("thread %i affinity set to %i\n",(pid==0)?(int)tid:pid,coreid);
  }
}
/*------------------------------------------------------------------------------------*/
/*
function implementing telnet server specific commands, parameters of the
telnet_cmdarray table
*/

void redirstd(char *newfname,telnet_printfunc_t prnt ) {
  FILE *fd;
  fd=freopen(newfname, "w", stdout);

  if (fd == NULL) {
    prnt("ERROR: stdout redir to %s error %s",strerror(errno));
  }

  fd=freopen(newfname, "w", stderr);

  if (fd == NULL) {
    prnt("ERROR: stderr redir to %s error %s",strerror(errno));
  }
}
int setoutput(char *buff, int debug, telnet_printfunc_t prnt) {
  char cmds[TELNET_MAX_MSGLENGTH/TELNET_CMD_MAXSIZE][TELNET_CMD_MAXSIZE];
  char *logfname;
  char stdout_str[64];
#define LOGFILE "logfile.log"
  memset(cmds,0,sizeof(cmds));
  sscanf(buff,"%9s %32s %9s %9s %9s", cmds[0],cmds[1],cmds[2],cmds[3],cmds[4]  );

  if (strncasecmp(cmds[0],"here",4) == 0) {
    fflush(stdout);
    sprintf(stdout_str,"/proc/%i/fd/%i",getpid(),telnetparams.new_socket);
    dup2(telnetparams.new_socket,fileno(stdout));
    //   freopen(stdout_str, "w", stdout);
    //   freopen(stdout_str, "w", stderr);
    dup2(telnetparams.new_socket,fileno(stderr));
    prnt("Log output redirected to this terminal (%s)\n",stdout_str);
  }

  if (strncasecmp(cmds[0],"file",4) == 0) {
    if (cmds[1][0] == 0)
      logfname=LOGFILE;
    else
      logfname=cmds[1];

    fflush(stdout);
    redirstd(logfname,prnt);
  }

  if (strncasecmp(cmds[0],"off",3) == 0) {
    fflush(stdout);
    redirstd("/dev/tty",prnt);
  }

  return CMDSTATUS_FOUND;
} /* setoutput */

int setparam(char *buff, int debug, telnet_printfunc_t prnt) {
  char cmds[TELNET_MAX_MSGLENGTH/TELNET_CMD_MAXSIZE][TELNET_CMD_MAXSIZE];
  memset(cmds,0,sizeof(cmds));
  sscanf(buff,"%9s %9s %9s %9s %9s", cmds[0],cmds[1],cmds[2],cmds[3],cmds[4]  );

  if (strncasecmp(cmds[0],"prio",4) == 0) {
    int prio;
    prio=(int)strtol(cmds[1],NULL,0);

    if (errno == ERANGE)
      return CMDSTATUS_VARNOTFOUND;

    telnetparams.priority = prio;
    set_sched(pthread_self(),0,prio);
    return CMDSTATUS_FOUND;
  }

  if (strncasecmp(cmds[0],"aff",3) == 0) {
    int aff;
    aff=(int)strtol(cmds[1],NULL,0);

    if (errno == ERANGE)
      return CMDSTATUS_VARNOTFOUND;

    set_affinity(pthread_self(),0,aff);
    return CMDSTATUS_FOUND;
  }

  return CMDSTATUS_NOTFOUND;
} /* setparam */

int history_cmd(char *buff, int debug, telnet_printfunc_t prnt) {
  char cmds[TELNET_MAX_MSGLENGTH/TELNET_CMD_MAXSIZE][TELNET_CMD_MAXSIZE];
  memset(cmds,0,sizeof(cmds));
  sscanf(buff,"%9s %9s %9s %9s %9s", cmds[0],cmds[1],cmds[2],cmds[3],cmds[4]  );

  if (cmds[0] == NULL)
    return CMDSTATUS_VARNOTFOUND;

  if (strncasecmp(cmds[0],"list",4) == 0) {
    HIST_ENTRY **hist = history_list();

    if (hist) {
      for (int i = 0; hist[i]; i++) {
        prnt ("%d: %s\n", i + history_base, hist[i]->line);
      }
    }

    return CMDSTATUS_FOUND;
  }

  if (strncasecmp(cmds[0],"reset",5) == 0) {
    clear_history();
    write_history(telnetparams.histfile);
    return CMDSTATUS_FOUND;
  }

  return CMDSTATUS_NOTFOUND;
} /* history_cmd */
/*-------------------------------------------------------------------------------------------------------*/
/*
generic commands available for all modules loaded by the server
*/

int setgetvar(int moduleindex,char getorset,char *params) {
  int n,i;
  char varname[TELNET_CMD_MAXSIZE];
  char *varval=NULL;
  memset(varname,0,sizeof(varname));
  n = sscanf(params,"%9s %ms",varname,&varval);

  for ( i=0 ; telnetparams.CmdParsers[moduleindex].var[i].varvalptr != NULL ; i++) {
    if ( strncasecmp(telnetparams.CmdParsers[moduleindex].var[i].varname,varname,strlen(telnetparams.CmdParsers[moduleindex].var[i].varname)) == 0) {
      if (n > 0 && (getorset == 'g' || getorset == 'G')) {
        client_printf("%s, %s = ", telnetparams.CmdParsers[moduleindex].module,
                      telnetparams.CmdParsers[moduleindex].var[i].varname );

        switch(telnetparams.CmdParsers[moduleindex].var[i].vartype) {
          case TELNET_VARTYPE_INT32:
            client_printf("%i\n",*(int32_t *)(telnetparams.CmdParsers[moduleindex].var[i].varvalptr));
            break;

          case TELNET_VARTYPE_INT64:
            client_printf("%lli\n",*(int64_t *)(telnetparams.CmdParsers[moduleindex].var[i].varvalptr));
            break;

          case TELNET_VARTYPE_INT16:
            client_printf("%hi\n",*(short *)(telnetparams.CmdParsers[moduleindex].var[i].varvalptr));
            break;

          case TELNET_VARTYPE_DOUBLE:
            client_printf("%g\n",*(double *)(telnetparams.CmdParsers[moduleindex].var[i].varvalptr));
            break;

          case TELNET_VARTYPE_STRING:
            client_printf("\"%s\"\n",*(char **)(telnetparams.CmdParsers[moduleindex].var[i].varvalptr));
            break;

          default:
            client_printf("unknown type\n");
            break;
        }
      }

      if (n > 1 && (getorset == 's' || getorset == 'S')) {
        client_printf("%s, %s set to \n", telnetparams.CmdParsers[moduleindex].module,
                      telnetparams.CmdParsers[moduleindex].var[i].varname);

        switch(telnetparams.CmdParsers[moduleindex].var[i].vartype) {
          case TELNET_VARTYPE_INT32:
            *(int *)(telnetparams.CmdParsers[moduleindex].var[i].varvalptr) = (int)strtol(varval,NULL,0);
            client_printf("%i\n",*(int *)(telnetparams.CmdParsers[moduleindex].var[i].varvalptr));
            break;

          case TELNET_VARTYPE_INT16:
            *(short *)(telnetparams.CmdParsers[moduleindex].var[i].varvalptr) = (short)strtol(varval,NULL,0);
            client_printf("%hi\n",*(short *)(telnetparams.CmdParsers[moduleindex].var[i].varvalptr));
            break;

          case TELNET_VARTYPE_DOUBLE:
            *(double *)(telnetparams.CmdParsers[moduleindex].var[i].varvalptr) = strtod(varval,NULL);
            client_printf("%g\n",*(double *)(telnetparams.CmdParsers[moduleindex].var[i].varvalptr));
            break;

          case TELNET_VARTYPE_STRING:
            sprintf(*(char **)(telnetparams.CmdParsers[moduleindex].var[i].varvalptr),"%s", varval);
            client_printf("\"%s\"\n",*(char **)(telnetparams.CmdParsers[moduleindex].var[i].varvalptr));
            break;

          default:
            client_printf("unknown type\n");
            break;
        }
      }
    }
  }

  if (n>1 && varval != NULL) {
    free(varval);
  }

  return CMDSTATUS_VARNOTFOUND;
}
/*----------------------------------------------------------------------------------------------------*/
char *get_time(char *buff,int bufflen) {
  struct tm  tmstruct;
  time_t now = time (0);
  strftime (buff, bufflen, "%Y-%m-%d %H:%M:%S.000", localtime_r(&now,&tmstruct));
  return buff;
}

int process_command(char *buf) {
  int i,j,k;
  char modulename[TELNET_CMD_MAXSIZE];
  char cmd[TELNET_CMD_MAXSIZE];
  char cmdb[TELNET_MAX_MSGLENGTH];
  char *bufbck;
  int rt;
  memset(modulename,0,sizeof(modulename));
  memset(cmd,0,sizeof(cmd));
  memset(cmdb,0,sizeof(cmdb));

  if (strncasecmp(buf,"ex",2) == 0)
    return CMDSTATUS_EXIT;

  if (strncasecmp(buf,"help",4) == 0) {
    for (i=0; telnetparams.CmdParsers[i].var != NULL && telnetparams.CmdParsers[i].cmd != NULL; i++) {
      client_printf("   module %i = %s:\n",i,telnetparams.CmdParsers[i].module);

      for(j=0; telnetparams.CmdParsers[i].var[j].varvalptr != NULL ; j++) {
        client_printf("      %s [get set] %s <value>\n",
                      telnetparams.CmdParsers[i].module, telnetparams.CmdParsers[i].var[j].varname);
      }

      for(j=0; telnetparams.CmdParsers[i].cmd[j].cmdfunc != NULL ; j++) {
        client_printf("      %s %s %s\n",
                      telnetparams.CmdParsers[i].module,telnetparams.CmdParsers[i].cmd[j].cmdname,
                      telnetparams.CmdParsers[i].cmd[j].helpstr);
      }
    }

    return CMDSTATUS_FOUND;
  }

  memset(modulename,0,sizeof(modulename));
  memset(cmd,0,sizeof(cmd));
  memset(cmdb,0,sizeof(cmdb));
  bufbck=strdup(buf);
  rt=CMDSTATUS_NOTFOUND;
  j = sscanf(buf,"%19s %19s %19[^\t\n]",modulename,cmd,cmdb);

  if (telnetparams.telnetdbg > 0)
    printf("process_command: %i words, module=%s cmd=%s, parameters= %s\n",j,modulename,cmd,cmdb);

  for (i=0; j>=2 && telnetparams.CmdParsers[i].var != NULL && telnetparams.CmdParsers[i].cmd != NULL; i++) {
    if ( (strncasecmp(telnetparams.CmdParsers[i].module,modulename,strlen(telnetparams.CmdParsers[i].module)) == 0)) {
      if (strncasecmp(cmd,"getall",7) == 0 ) {
        for(j=0; telnetparams.CmdParsers[i].var[j].varvalptr != NULL ; j++) {
          setgetvar(i,'g',telnetparams.CmdParsers[i].var[j].varname);
        }

        rt= CMDSTATUS_FOUND;
      } else if (strncasecmp(cmd,"get",3) == 0 || strncasecmp(cmd,"set",3) == 0) {
        rt= setgetvar(i,cmd[0],cmdb);
      } else {
        for (k=0 ; telnetparams.CmdParsers[i].cmd[k].cmdfunc != NULL ; k++) {
          if (strncasecmp(cmd, telnetparams.CmdParsers[i].cmd[k].cmdname,sizeof(telnetparams.CmdParsers[i].cmd[k].cmdname)) == 0) {
            telnetparams.CmdParsers[i].cmd[k].cmdfunc(cmdb, telnetparams.telnetdbg, client_printf);
            rt= CMDSTATUS_FOUND;
          }
        } /* for k */
      }/* else */
    }/* strncmp: module name test */
    else if (strncasecmp(modulename,"loop",4) == 0 ) {
      int f = fcntl(telnetparams.new_socket,F_GETFL);
      int f1=fcntl (telnetparams.new_socket, F_SETFL, O_NONBLOCK | f);

      if (f<0 || f1 <0) {
        client_printf( " Loop won't be cancelable: %s\n",strerror(errno) );
      }

      for(int lc=0; lc<telnetparams.loopcount; lc++) {
        char dummybuff[20];
        char tbuff[64];
        client_printf(CSI "1J" CSI "1;10H         " STDFMT "%s %i/%i\n",
                      get_time(tbuff,sizeof(tbuff)),lc,telnetparams.loopcount );
        process_command(bufbck+strlen("loop")+1);
        errno=0;
        int rs = read(telnetparams.new_socket,dummybuff,sizeof(dummybuff));

        if (telnetparams.telnetdbg > 0)
          client_printf("Received \"%s\" status %d, errno %s while running loop\n",dummybuff,rs,strerror(errno));

        if ( errno != EAGAIN && errno != EWOULDBLOCK) {
          client_printf( STDFMT " Loop canceled, iteration %i/%i\n",lc,telnetparams.loopcount );
          lc=telnetparams.loopcount;
          break;
        }

        usleep(telnetparams.loopdelay * 1000);
      }

      fcntl (telnetparams.new_socket, F_SETFL, f);
      rt= CMDSTATUS_FOUND;
    } /* loop */
  } /* for i */

  free(bufbck);
  return rt;
}

void run_telnetsrv(void) {
  int sock;
  struct sockaddr_in name;
  char buf[TELNET_MAX_MSGLENGTH];
  struct sockaddr cli_addr;
  unsigned int cli_len = sizeof(cli_addr);
  int readc, filled;
  int status;
  int optval = 1;
  pthread_setname_np(pthread_self(), "telnet");
  set_sched(pthread_self(),0,telnetparams.priority);
  sock = socket(AF_INET, SOCK_STREAM, 0);

  if (sock < 0)
    fprintf(stderr,"[TELNETSRV] Error %s on socket call\n",strerror(errno));

  setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &optval, sizeof optval);
  name.sin_family = AF_INET;

  if (telnetparams.listenaddr == 0)
    name.sin_addr.s_addr = INADDR_ANY;
  else
    name.sin_addr.s_addr = telnetparams.listenaddr;

  name.sin_port = htons((unsigned short)(telnetparams.listenport));

  if(bind(sock, (void *) &name, sizeof(name)))
    fprintf(stderr,"[TELNETSRV] Error %s on bind call\n",strerror(errno));

  if(listen(sock, 1) == -1)
    fprintf(stderr,"[TELNETSRV] Error %s on listen call\n",strerror(errno));

  using_history();
  printf("\nInitializing telnet server...\n");

  while( (telnetparams.new_socket = accept(sock, &cli_addr, &cli_len)) ) {
    printf("[TELNETSRV] Telnet client connected....\n");
    read_history(telnetparams.histfile);
    stifle_history(telnetparams.histsize);

    if(telnetparams.new_socket < 0)
      fprintf(stderr,"[TELNETSRV] Error %s on accept call\n",strerror(errno));

    while(telnetparams.new_socket>0) {
      filled = 0;
      memset(buf,0,sizeof(buf));

      while(filled < ( TELNET_MAX_MSGLENGTH-1)) {
        readc = recv(telnetparams.new_socket, buf+filled, TELNET_MAX_MSGLENGTH-filled-1, 0);

        if(!readc)
          break;

        filled += readc;

        if(buf[filled-1] == '\n') {
          buf[filled-1] = 0;
          break;
        }
      }

      if(!readc) {
        printf ("[TELNETSRV] Telnet Client disconnected.\n");
        break;
      }

      if (telnetparams.telnetdbg > 0)
        printf("[TELNETSRV] Command received: readc %i filled %i \"%s\"\n", readc, filled,buf);

      if (buf[0] == '!') {
        if (buf[1] == '!') {
          sprintf(buf,"%s","telnet history list");
        } else {
          HIST_ENTRY *hisentry = history_get(strtol(buf+1,NULL,0));

          if (hisentry) {
            char msg[TELNET_MAX_MSGLENGTH + sizeof(TELNET_PROMPT) +10];
            sprintf(buf,"%s",hisentry->line);
            sprintf(msg,"%s %s\n",TELNET_PROMPT, hisentry->line);
            send(telnetparams.new_socket, msg, strlen(msg), MSG_NOSIGNAL);
          }
        }
      }

      if (strlen(buf) > 2 ) {
        status=process_command(buf);
      } else
        status=CMDSTATUS_NOCMD;

      if (status != CMDSTATUS_EXIT) {
        if (status == CMDSTATUS_NOTFOUND) {
          char msg[TELNET_MAX_MSGLENGTH + 50];
          sprintf(msg,"Error: \n      %s\n is not a softmodem command\n",buf);
          send(telnetparams.new_socket, msg, strlen(msg), MSG_NOSIGNAL);
        } else if (status == CMDSTATUS_FOUND) {
          add_history(buf);
        }

        send(telnetparams.new_socket, TELNET_PROMPT, sizeof(TELNET_PROMPT), MSG_NOSIGNAL);
      } else {
        printf ("[TELNETSRV] Closing telnet connection...\n");
        break;
      }
    }

    write_history(telnetparams.histfile);
    clear_history();
    close(telnetparams.new_socket);
    printf ("[TELNETSRV] Telnet server waitting for connection...\n");
  }

  close(sock);
  return;
}

/*------------------------------------------------------------------------------------------------*/
/* set_telnetmodule loads the commands delivered with the telnet server
 *
 *
 *
*/
void exec_moduleinit(char *modname) {
  void (*fptr)(void);
  char initfunc[TELNET_CMD_MAXSIZE+9];

  if (strlen(modname) > TELNET_CMD_MAXSIZE) {
    fprintf(stderr,"[TELNETSRV] module %s not loaded, name exceeds the %i size limit\n",
            modname, TELNET_CMD_MAXSIZE);
    return;
  }

  sprintf(initfunc,"add_%s_cmds",modname);
  fptr = dlsym(RTLD_DEFAULT,initfunc);

  if ( fptr != NULL) {
    fptr();
  } else {
    fprintf(stderr,"[TELNETSRV] couldn't find %s for module %s \n",initfunc,modname);
  }
}

int add_embeddedmodules(void) {
  int ret=0;

  for(int i=0; i<telnetoptions[TELNETSRV_STATICMOD].numelt; i++) {
    ret++;
    exec_moduleinit(telnetoptions[TELNETSRV_STATICMOD].strlistptr[i]);
  }

  return ret;
}

int add_sharedmodules(void) {
  char initfunc[TELNET_CMD_MAXSIZE+9];
  void (*fptr)(void);
  int ret=0;

  for(int i=0; i<telnetoptions[TELNETSRV_SHRMOD].numelt; i++) {
    sprintf(initfunc,"add_%s_cmds",telnetoptions[TELNETSRV_SHRMOD].strlistptr[i]);
    fptr = dlsym(RTLD_DEFAULT,initfunc);

    if ( fptr != NULL) {
      fptr();
      ret++;
    } else {
      fprintf(stderr,"[TELNETSRV] couldn't find %s for module %s \n",initfunc,telnetoptions[TELNETSRV_STATICMOD].strlistptr[i]);
    }
  }

  return ret;
}

int telnetsrv_autoinit(void) {
  memset(&telnetparams,0,sizeof(telnetparams));
  config_get( telnetoptions,sizeof(telnetoptions)/sizeof(paramdef_t),"telnetsrv");

  if(pthread_create(&telnetparams.telnet_pthread,NULL, (void *(*)(void *))run_telnetsrv, NULL) != 0) {
    fprintf(stderr,"[TELNETSRV] Error %s on pthread_create call\n",strerror(errno));
    return -1;
  }

  add_telnetcmd("telnet", telnet_vardef, telnet_cmdarray);
  add_embeddedmodules();
  return 0;
}

/*---------------------------------------------------------------------------------------------*/
/* add_telnetcmd is used to add a set of commands to the telnet server. A module calls this
 * function at init time. the telnet server is delivered with a set of commands which
 * will be loaded or not depending on the telnet section of the config file
*/
int add_telnetcmd(char *modulename, telnetshell_vardef_t *var, telnetshell_cmddef_t *cmd) {
  int i;

  if( modulename == NULL || var == NULL || cmd == NULL) {
    fprintf(stderr,"[TELNETSRV] Telnet server, add_telnetcmd: invalid parameters\n");
    return -1;
  }

  for (i=0; i<TELNET_MAXCMD ; i++) {
    if (telnetparams.CmdParsers[i].var == NULL) {
      strncpy(telnetparams.CmdParsers[i].module,modulename,sizeof(telnetparams.CmdParsers[i].module)-1);
      telnetparams.CmdParsers[i].cmd = cmd;
      telnetparams.CmdParsers[i].var = var;
      printf("[TELNETSRV] Telnet server: module %i = %s added to shell\n",
             i,telnetparams.CmdParsers[i].module);
      break;
    }
  }

  return 0;
}


/* function which will be called by the shared lib loader, to check shared lib version
   against main exec version. version mismatch no considered as fatal (interfaces not supposed to change)
*/
int  telnetsrv_checkbuildver(char *mainexec_buildversion, char **shlib_buildversion) {
#ifndef PACKAGE_VERSION
#define PACKAGE_VERSION "standalone built: " __DATE__ __TIME__
#endif
  *shlib_buildversion = PACKAGE_VERSION;

  if (strcmp(mainexec_buildversion, *shlib_buildversion) != 0) {
    fprintf(stderr,"[TELNETSRV] shared lib version %s, doesn't match main version %s, compatibility should be checked\n",
            mainexec_buildversion,*shlib_buildversion);
  }

  return 0;
}

int telnetsrv_getfarray(loader_shlibfunc_t  **farray) {
  *farray=malloc(sizeof(loader_shlibfunc_t));
  (*farray)[0].fname=TELNET_ADDCMD_FNAME;
  (*farray)[0].fptr=(int (*)(void) )add_telnetcmd;
  return 1;
}