/* hey emacs! -*- Mode: C; c-file-style: "k&r"; indent-tabs-mode: nil -*- */
/*
 * tftpd.c
 *    main server file
 *
 * $Id: tftpd.c,v 1.61 2004/02/27 02:05:26 jp Exp $
 *
 * Copyright (c) 2000 Jean-Pierre Lefebvre <helix@step.polymtl.ca>
 *                and Remi Lefebvre <remi@debian.org>
 *
 * atftp is free software; you can redistribute them and/or modify them
 * 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.
 *
 */

#include "config.h"

#include <stdio.h>
#include <stdlib.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <getopt.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h> 
#include <pthread.h>
#include <string.h>
#include <pwd.h>
#include <grp.h>
#ifdef HAVE_WRAP
#include <tcpd.h>
#endif
#include "tftpd.h"
#include "tftp_io.h"
#include "tftp_def.h"
#include "logger.h"
#include "options.h"
#include "stats.h"
#ifdef HAVE_PCRE
#include "tftpd_pcre.h"
#endif
#ifdef HAVE_MTFTP
#include "tftpd_mtftp.h"
#endif

#undef RATE_CONTROL

/*
 * Global variables set by main when starting. Read-only for threads
 */
int tftpd_max_thread = 100;     /* number of concurent thread allowed */
int tftpd_timeout = 300;        /* number of second of inactivity
                                   before exiting */
char directory[MAXLEN] = "/srv/tftp/";
int retry_timeout = S_TIMEOUT;

int on = 1;
int listen_local = 0;

int tftpd_daemon = 0;           /* By default we are started by inetd */
int tftpd_daemon_no_fork = 0;   /* For who want a false daemon mode */
short tftpd_port = 0;           /* Port atftpd listen to */
char tftpd_addr[MAXLEN] = "";   /* IP address atftpd binds to */

int tftpd_cancel = 0;           /* When true, thread must exit. pthread
                                   cancellation point are not used because
                                   thread id are not tracked. */
char *pidfile = NULL;           /* File to write own's pid */

pthread_t main_thread_id;

/*
 * Multicast related. These reflect option from command line
 * argument --mcast-ttl, --mcast-port and  --mcast-addr
 */
int mcast_ttl = 1;
char mcast_addr[MAXLEN] = "239.255.0.0-255";
char mcast_port[MAXLEN] = "1758";

/*
 * "logging level" is the maximum error level that will get logged.
 *  This can be increased with the -v switch.
 */
int logging_level = LOG_NOTICE;
char *log_file = NULL;

/* logging level as requested by libwrap */
#ifdef HAVE_WRAP
int allow_severity = LOG_NOTICE;
int deny_severity = LOG_NOTICE;
#endif

/* user ID and group ID when running as a daemon */
char user_name[MAXLEN] = "nobody";
char group_name[MAXLEN] = "nogroup";

/* For special uses, disable source port checking */
int source_port_checking = 1;

/* Special feature to make the server switch to new client as soon as
   the current client timeout in multicast mode */
int mcast_switch_client = 0;

int trace = 0;

#ifdef HAVE_PCRE
/* Use for PCRE file name substitution */
tftpd_pcre_self_t *pcre_top = NULL;
char *pcre_file;
#endif

#ifdef HAVE_MTFTP
/* mtftp options */
struct mtftp_data *mtftp_data = NULL;
char mtftp_file[MAXLEN] = "";
int mtftp_sport = 75;
#endif

#ifdef RATE_CONTROL
int rate = 0;
#endif

/*
 * We need a lock on stdin from the time we notice fresh data coming from
 * stdin to the time the freshly created server thread as read it.
 */
pthread_mutex_t stdin_mutex = PTHREAD_MUTEX_INITIALIZER;

/*
 * Function defined in this file
 */
void *tftpd_receive_request(void *);
void signal_handler(int signal);
int tftpd_cmd_line_options(int argc, char **argv);
void tftpd_log_options(void);
int tftpd_pid_file(char *file, int action);
void tftpd_usage(void);

/*
 * Main thread. Do required initialisation and then go through a loop
 * listening for client requests. When a request arrives, we allocate
 * memory for a thread data structure and start a thread to serve the
 * new client. If theres no activity for more than 'tftpd_timeout'
 * seconds, we exit and tftpd must be respawned by inetd.
 */
int main(int argc, char **argv)
{
     fd_set rfds;               /* for select */
     struct timeval tv;         /* for select */
     int run = 1;               /* while (run) loop */
     struct thread_data *new;   /* for allocation of new thread_data */
     int sockfd;                /* used in daemon mode */
     struct sockaddr_storage sa; /* used in daemon mode */
     struct passwd *user;
     struct group *group;
     pthread_t tid;

#ifdef HAVE_MTFTP
     pthread_t mtftp_thread;
#endif

#ifdef RATE_CONTROL
     struct timeval current_time = {0, 0}; /* For rate control */
     long long current = 0L;
     struct timeval previous_time = {0, 0};
     long long previous = 0L;
     int rcvbuf;                /* size of input socket buffer */
#endif
     int one = 1;               /* for setsockopt() */

     /*
      * Parse command line options. We parse before verifying
      * if we are running on a tty or not to make it possible to
      * verify the command line arguments
      */
     if (tftpd_cmd_line_options(argc, argv) == ERR)
          exit(1);

     /*
      * Can't be started from the prompt without explicitely specifying 
      * the --daemon option.
      */
     if (isatty(0) && !(tftpd_daemon))
     {
          tftpd_usage();
          exit(1);
     }

     /* Using syslog facilties through a wrapper. This call divert logs
      * to a file as specified or to syslog if no file specified. Specifying
      * /dev/stderr or /dev/stdout will work if the server is started in
      * daemon mode.
      */
     open_logger("atftpd", log_file, logging_level);
     logger(LOG_NOTICE, "Advanced Trivial FTP server started (%s)", VERSION);

#ifdef HAVE_PCRE
     /*  */
     if (pcre_file)
     {
          if ((pcre_top = tftpd_pcre_open(pcre_file)) == NULL)
               logger(LOG_WARNING, "Failed to initialise PCRE, continuing anyway.");
     }
#endif

#ifdef RATE_CONTROL
     /* Some tuning */
     rcvbuf = 128;
     if (setsockopt(0, SOL_SOCKET, SO_RCVBUF, &rcvbuf, sizeof(rcvbuf)) == 0)
     {
          logger(LOG_WARNING, "Failed to set socket option: %s", strerror(errno));
     }
     logger(LOG_DEBUG, "Receive socket buffer set to %d bytes", rcvbuf);
#endif

     /*
      * If tftpd is run in daemon mode ...
      */
     if (tftpd_daemon)
     {
          /* daemonize here */
          if (!tftpd_daemon_no_fork)
          {
               if (daemon(0, 0) == -1)
                    exit(2);
          }

          /* find the port; initialise sockaddr_storage structure */
          if (strlen(tftpd_addr) > 0 || tftpd_port == 0)
          {
               struct addrinfo hints, *result;
               int err;

               /* look up the service and host */
               memset(&hints, 0, sizeof(hints));
               hints.ai_socktype = SOCK_DGRAM;
               hints.ai_flags = AI_NUMERICHOST;
               err = getaddrinfo(tftpd_addr, tftpd_port ? NULL : "tftp",
                                 &hints, &result);
               if (err == EAI_SERVICE)
               {
                    logger(LOG_ERR, "atftpd: udp/tftp, unknown service");
                    exit(1);
               }
               if (err || sockaddr_set_addrinfo(&sa, result))
               {
                    logger(LOG_ERR, "atftpd: invalid IP address %s", tftpd_addr);
                    exit(1);
               }

               if (!tftpd_port)
                    tftpd_port = sockaddr_get_port(&sa);
               else {
                    sa.ss_family = AF_INET;
                    sockaddr_set_port(&sa, tftpd_port);
               }

               freeaddrinfo(result);
          }

          if (strlen(tftpd_addr) == 0)
          {
               memset(&sa, 0, sizeof(sa));
               sa.ss_family = AF_INET;
          }
          sockaddr_set_port(&sa, tftpd_port);

          /* open the socket */
          if ((sockfd = socket(sa.ss_family, SOCK_DGRAM, 0)) == 0)
          {
               logger(LOG_ERR, "atftpd: can't open socket");
               exit(1);
          }
          /* bind the socket to the desired address and port  */
          if (bind(sockfd, (struct sockaddr*)&sa, sizeof(sa)) < 0)
          {
               logger(LOG_ERR, "atftpd: can't bind port %s:%d/udp",
                      tftpd_addr, tftpd_port);
               exit(1);
          }
          /*
           * dup sockfd on 0 only, not 1,2 like inetd do to allow
           * logging to stderr in pseudo daemon mode (--daemon --no-fork)
           */
          dup2(sockfd, 0);
          close(sockfd);

          /* release priviliedge */
          user = getpwnam(user_name);
          group = getgrnam(group_name);
          if (!user || !group)
          {
               logger(LOG_ERR,
                      "atftpd: can't change identity to %s.%s, exiting.",
                      user_name, group_name);
               exit(1);
          }

          /* write our pid in the specified file before changing user*/
          if (pidfile)
          {
               if (tftpd_pid_file(pidfile, 1) != OK)
                    exit(1);
               /* to be able to remove it later */
               chown(pidfile, user->pw_uid, group->gr_gid);
          }

          setgid(group->gr_gid);
          setuid(user->pw_uid);

          /* Reopen log file now that we changed user, and that we've
           * open and dup2 the socket. */
          open_logger("atftpd", log_file, logging_level);
     }

#if defined(SOL_IP) && defined(IP_PKTINFO)
     /* We need to retieve some information from incomming packets */
     if (setsockopt(0, SOL_IP, IP_PKTINFO, &one, sizeof(one)) != 0)
     {
          logger(LOG_WARNING, "Failed to set socket option: %s", strerror(errno));
     }
#endif

     /* save main thread ID for proper signal handling */
     main_thread_id = pthread_self();

     /* Register signal handler. */
     signal(SIGINT, signal_handler);
     signal(SIGTERM, signal_handler);

     /* print summary of options */
     tftpd_log_options();

     /* start collecting stats */
     stats_start();

#ifdef HAVE_MTFTP
     /* start mtftp server thread */
     if (strlen(mtftp_file) > 0)
     {
          if (!tftpd_daemon)
               logger(LOG_ERR, "Can't start mtftp server, use --deamon");
          else
          {
               if ((mtftp_data = tftpd_mtftp_init(mtftp_file)) == NULL)
                    logger(LOG_ERR, "Failled initialise mtftp");
               else
               {
                    mtftp_data->server_port = mtftp_sport;
                    mtftp_data->mcast_ttl = mcast_ttl;
                    mtftp_data->timeout = retry_timeout;
                    mtftp_data->checkport = source_port_checking;
                    mtftp_data->trace = trace;
                    /* Start server thread. */
                    if (pthread_create(&mtftp_thread, NULL, tftpd_mtftp_server,
                                       (void *)mtftp_data) != 0)
                    {
                         logger(LOG_ERR, "Failed to start mtftp server thread");
                         tftpd_mtftp_clean(mtftp_data);
                         mtftp_data = NULL;
                    } 
              }
          }
     }
#endif

     /* Wait for read or write request and exit if timeout. */
     while (run)
     {
          /*
           * inetd dups the socket file descriptor to 0, 1 and 2 so we can
           * use any of those as the socket fd. We use 0. stdout and stderr
           * may not be used to print messages.
           */
          FD_ZERO(&rfds);
          FD_SET(0, &rfds);
          tv.tv_sec = tftpd_timeout;
          tv.tv_usec = 0;

          /* We need to lock stdin, and release it when the thread
             is done reading the request. */
          pthread_mutex_lock(&stdin_mutex);

#ifdef RATE_CONTROL          
          /* if we want to implement rate control, we sleep some time here
             so we cannot exceed the allowed thread/sec. */
          if (rate > 0)
          {
               gettimeofday(&current_time, NULL);
               current = (long long)current_time.tv_sec*1000000L + current_time.tv_usec;
               logger(LOG_DEBUG, "time from previous request: %Ld", current - previous);
               if ((current - previous) < (60L*1000000L / (long long)rate))
               {
                    logger(LOG_DEBUG, "will sleep for rate control (%Ld)",
                           (60L*1000000L / (long long)rate) - (current - previous));
                    usleep((60L*1000000L / (long long)rate) - (current - previous));
               }
          }
#endif

          /* A timeout of 0 is interpreted as infinity. Wait for incomming
             packets */
          if (!tftpd_cancel)
          {
               int rv;

               if ((tftpd_timeout == 0) || (tftpd_daemon))
                    rv = select(FD_SETSIZE, &rfds, NULL, NULL, NULL);
               else
                    rv = select(FD_SETSIZE, &rfds, NULL, NULL, &tv);
               if (rv < 0) {
                    logger(LOG_ERR, "%s: %d: select: %s",
                           __FILE__, __LINE__, strerror(errno));
                    /* Clear the bits, they are undefined! */
                    FD_ZERO(&rfds);
	       }
          }

#ifdef RATE_CONTROL
          /* get the time we receive this packet */
          if (rate > 0)
          {
               gettimeofday(&previous_time, NULL);
               previous = (long long)previous_time.tv_sec*1000000L +
                    previous_time.tv_usec;
          }
#endif

          if (FD_ISSET(0, &rfds) && (!tftpd_cancel))
          {
               /* Allocate memory for thread_data structure. */
               if ((new = calloc(1, sizeof(struct thread_data))) == NULL)
               {
                    logger(LOG_ERR, "%s: %d: Memory allocation failed",
                           __FILE__, __LINE__);
                    exit(1);
               }

               /*
                * Initialisation of thread_data structure.
                */
               pthread_mutex_init(&new->client_mutex, NULL);
               new->sockfd = 0;

               /* Allocate data buffer for tftp transfer. */
               if ((new->data_buffer = malloc((size_t)SEGSIZE + 4)) == NULL)
               {
                    logger(LOG_ERR, "%s: %d: Memory allocation failed",
                           __FILE__, __LINE__);
                    exit(1);
               }
               new->data_buffer_size = SEGSIZE + 4;

               /* Allocate memory for tftp option structure. */
               if ((new->tftp_options = 
                    malloc(sizeof(tftp_default_options))) == NULL)
               {
                    logger(LOG_ERR, "%s: %d: Memory allocation failed",
                           __FILE__, __LINE__);
                    exit(1);
               }

               /* Copy default options. */
               memcpy(new->tftp_options, tftp_default_options,
                      sizeof(tftp_default_options));

               /* default timeout */
               new->timeout = retry_timeout;

               /* wheter we check source port or not */
               new->checkport = source_port_checking;

               /* other options */
               new->mcast_switch_client = mcast_switch_client;
               new->trace = trace;

               /* default ttl for multicast */
               new->mcast_ttl = mcast_ttl;

               /* Allocate memory for a client structure. */
               if ((new->client_info =
                    calloc(1, sizeof(struct client_info))) == NULL)
               {
                    logger(LOG_ERR, "%s: %d: Memory allocation failed",
                           __FILE__, __LINE__);
                    exit(1);
               }
               new->client_info->done = 0;
               new->client_info->next = NULL;
               
               /* Start a new server thread. */
               if (pthread_create(&tid, NULL, tftpd_receive_request,
                                  (void *)new) != 0)
               {
                    logger(LOG_ERR, "Failed to start new thread");
                    free(new);
                    pthread_mutex_unlock(&stdin_mutex);
               }
          }
          else
          {
               pthread_mutex_unlock(&stdin_mutex);
               
               /* Either select return after timeout of we've been killed. In the first case
                  we wait for server thread to finish, in the other we kill them */
               if (tftpd_cancel)
                    tftpd_list_kill_threads();

               while (tftpd_list_num_of_thread() != 0)
                    sleep(1);

               run = 0;
               if (tftpd_daemon || (tftpd_timeout == 0))
                    logger(LOG_NOTICE, "atftpd terminating");
               else
                    logger(LOG_NOTICE,
                           "atftpd terminating after %d seconds",
                           tftpd_timeout);
          }
     }

     /* close all open file descriptors */
     close(0);
     close(1);
     close(2);

#ifdef HAVE_MTFTP
     /*  stop the mtftp threads */
     if (mtftp_data)
     {
          /* kill mtftp serving thread */
          tftpd_mtftp_kill_threads(mtftp_data);
          /* kill mtftp main thread */
          pthread_kill(mtftp_thread, SIGTERM);
          pthread_join(mtftp_thread, NULL);
     }
#endif

     /* stop collecting stats and print them*/
     stats_end();
     stats_print();
     
#ifdef HAVE_PCRE
     /* remove allocated memory for tftpd_pcre */
     if (pcre_top)
          tftpd_pcre_close(pcre_top);
#endif

     /* some cleaning */
     if (log_file)
          free(log_file);
#ifdef HAVE_PCRE
     if (pcre_file)
          free(pcre_file);
#endif

     /* remove PID file */
     if (pidfile)
          tftpd_pid_file(pidfile, 0);

     logger(LOG_NOTICE, "Main thread exiting");
     close_logger();
     exit(0);
}

/* 
 * This function handles the initial connection with a client. It reads
 * the request from stdin and then release the stdin_mutex, so the main
 * thread may listen for new clients. After that, we process options and
 * call the sending or receiving function.
 *
 * arg is a thread_data structure pointer for that thread.
 */
void *tftpd_receive_request(void *arg)
{
     struct thread_data *data = (struct thread_data *)arg;
     
     int retval;                /* hold return value for testing */
     int data_size;             /* returned size by recvfrom */
     char string[MAXLEN];       /* hold the string we pass to the logger */
     int num_of_threads;
     int abort = 0;             /* 1 if we need to abort because the maximum
                                   number of threads have been reached*/ 
     struct sockaddr_storage to; /* destination of client's packet */
     socklen_t len = sizeof(to);

     char addr_str[SOCKADDR_PRINT_ADDR_LEN];

     /* Detach ourself. That way the main thread does not have to
      * wait for us with pthread_join. */
     data->tid = pthread_self();
     pthread_detach(data->tid);

     /* Read the first packet from stdin. */
     data_size = data->data_buffer_size;     
     retval = tftp_get_packet(0, -1, NULL, &data->client_info->client, NULL,
                              &to, data->timeout, &data_size,
                              data->data_buffer);
     if (retval == ERR) {
          logger(LOG_NOTICE, "Invalid request in 1st packet");
          abort = 1;
     }

     /* now unlock stdin */
     pthread_mutex_unlock(&stdin_mutex);

     /* Verify the number of threads */
     if ((num_of_threads = tftpd_list_num_of_thread()) >= tftpd_max_thread)
     {
          logger(LOG_INFO, "Maximum number of threads reached: %d",
                 num_of_threads);
          abort = 1;
     }

#ifdef HAVE_WRAP
     if (!abort)
     {
          /* Verify the client has access. We don't look for the name but
             rely only on the IP address for that. */
          sockaddr_print_addr(&data->client_info->client,
                              addr_str, sizeof(addr_str));
          if (hosts_ctl("in.tftpd", STRING_UNKNOWN, addr_str,
                        STRING_UNKNOWN) == 0)
          {
               logger(LOG_ERR, "Connection refused from %s", addr_str);
               abort = 1;
          }
     }
#endif

     /* Add this new thread structure to the list. */
     if (!abort)
          stats_new_thread(tftpd_list_add(data));

     /* if the maximum number of thread is reached, too bad we abort. */
     if (abort)
          stats_abort_locked();
     else
     {
          /* open a socket for client communication */
          data->sockfd = socket(data->client_info->client.ss_family,
                                SOCK_DGRAM, 0);
          /*memset(&to, 0, sizeof(to));*/
          /* PSz 11 Aug 2011  http://bugs.debian.org/613582
           * Do not nullify "to", preserve IP address from tftp_get_packet().
           * Only set port to 0, as we used to in v6.
           * (Why set ss_family, was not it right already??)
           */
          to.ss_family = data->client_info->client.ss_family;
          sockaddr_set_port(&to, 0);
          /* Force socket to listen on local address. Do not listen on broadcast address 255.255.255.255. 
             If the socket listens on the broadcast address, Linux tells the remote client the port
             is unreachable. This happens even if SO_BROADCAST is set in setsockopt for this socket.
             I was unable to find a kernel option or /proc/sys flag to make the kernel pay attention to 
             these requests, so the workaround is to force listening on the local address. */
          if (listen_local == 1)
          { 
               logger(LOG_INFO, "forcing socket to listen on local address");
               if (setsockopt(data->sockfd, SOL_SOCKET, SO_BROADCAST, &on, sizeof(on)) != 0) {
                  logger(LOG_ERR, "setsockopt: %s", strerror(errno));
               }
          }
          else
          {
               logger(LOG_INFO, "socket may listen on any address, including broadcast");
          }

          if (data->sockfd > 0)
          {
               /* bind the socket to the interface */
               if (bind(data->sockfd, (struct sockaddr *)&to, len) == -1)
               {
                    logger(LOG_ERR, "bind: %s", strerror(errno));
                    retval = ABORT;
               }
               /* read back assigned port */
               len = sizeof(to);
               if (getsockname(data->sockfd, (struct sockaddr *)&to, &len) == -1)
               {
                    logger(LOG_ERR, "getsockname: %s", strerror(errno));
                    retval = ABORT;
               }
               /* connect the socket, faster for kernel operation */
               /* this is not a good idea on FreeBSD, because sendto() cannot
                  be used on a connected datagram socket */
#if !defined(__FreeBSD_kernel__)
               if (connect(data->sockfd,
                           (struct sockaddr *)&data->client_info->client,
                           sizeof(data->client_info->client)) == -1)
               {
                    logger(LOG_ERR, "connect: %s", strerror(errno));
                    retval = ABORT;
               }
#endif
               logger(LOG_DEBUG, "Creating new socket: %s:%d",
                      sockaddr_print_addr(&to, addr_str, sizeof(addr_str)),
                      sockaddr_get_port(&to));
               
               /* read options from request */
               opt_parse_request(data->data_buffer, data_size,
                                 data->tftp_options);
               opt_request_to_string(data->tftp_options, string, MAXLEN);
          }
          else
          {
               retval = ABORT;
          }

          /* Analyse the request. */
          switch (retval)
          {
          case GET_RRQ:
               logger(LOG_NOTICE, "Serving %s to %s:%d",
                      data->tftp_options[OPT_FILENAME].value,
                      sockaddr_print_addr(&data->client_info->client,
                                          addr_str, sizeof(addr_str)),
                      sockaddr_get_port(&data->client_info->client));
               if (data->trace)
                    logger(LOG_DEBUG, "received RRQ <%s>", string);
               if (tftpd_send_file(data) == OK)
                    stats_send_locked();
               else
                    stats_err_locked();
               break;
          case GET_WRQ:
               logger(LOG_NOTICE, "Fetching from %s to %s",
                      sockaddr_print_addr(&data->client_info->client,
                                          addr_str, sizeof(addr_str)),
                      data->tftp_options[OPT_FILENAME].value);
               if (data->trace)
                    logger(LOG_DEBUG, "received WRQ <%s>", string);
               if (tftpd_receive_file(data) == OK)
                    stats_recv_locked();
               else
                    stats_err_locked();
               break;
          case ERR:
               logger(LOG_ERR, "Error from tftp_get_packet");
               tftp_send_error(data->sockfd, &data->client_info->client,
                               EUNDEF, data->data_buffer, data->data_buffer_size);
               if (data->trace)
                    logger(LOG_DEBUG, "sent ERROR <code: %d, msg: %s>", EUNDEF,
                           tftp_errmsg[EUNDEF]);
               stats_err_locked();
               break;
          case ABORT:
               if (data->trace)
                    logger(LOG_ERR, "thread aborting");
               stats_err_locked();
               break;
          default:
               logger(LOG_NOTICE, "Invalid request <%d> from %s",
                      retval,
                      sockaddr_print_addr(&data->client_info->client,
                                          addr_str, sizeof(addr_str)));
               tftp_send_error(data->sockfd, &data->client_info->client,
                               EBADOP, data->data_buffer, data->data_buffer_size);
               if (data->trace)
                    logger(LOG_DEBUG, "sent ERROR <code: %d, msg: %s>", EBADOP,
                           tftp_errmsg[EBADOP]);
               stats_err_locked();
          }
     }  

     /* make sure all data is sent to the network */
     if (data->sockfd)
     {
          fsync(data->sockfd);
          close(data->sockfd);
     }

     /* update stats */
     stats_thread_usage_locked();

     /* Remove the thread_data structure from the list, if it as been
        added. */
     if (!abort)
          tftpd_list_remove(data);

     /* Free memory. */
     if (data->data_buffer)
          free(data->data_buffer);

     free(data->tftp_options);

     /* if the thread had reserverd a multicast IP/Port, deallocate it */
     if (data->mc_port != 0)
          tftpd_mcast_free_tid(data->mc_addr, data->mc_port);

     /* this function take care of freeing allocated memory by other threads */
     tftpd_clientlist_free(data);

     /* free the thread structure */
     free(data);    

     logger(LOG_INFO, "Server thread exiting");
     pthread_exit(NULL);
}

/*
 * If we receive signals, we must exit in a clean way. This means
 * sending an ERROR packet to all clients to terminate the connection.
 */
void signal_handler(int signal)
{
     /* Any thread may receive the signal, always make sure the main thread receive it
        and cancel other threads itself. However, if tftpd_cancel already set, just
        ignore the signal since the master thread as already got the signal. */
     if (pthread_self() != main_thread_id)
     {
          if (tftpd_cancel == 0)
          {
               logger(LOG_ERR, "Forwarding signal to main thread");
               pthread_kill(main_thread_id, signal);
          }
          return;
     }

     /* Only signals for the main thread get there */
     switch (signal)
     {
     case SIGINT:
          logger(LOG_ERR, "SIGINT received, stopping threads and exiting.");
          tftpd_cancel = 1;
          break;
     case SIGTERM:
          logger(LOG_ERR, "SIGTERM received, stopping threads and exiting.");
          tftpd_cancel = 1;
          break;
     default:
          logger(LOG_WARNING, "Signal %d received, ignoring.", signal);
          break;
     }
}

#define OPT_RATE       'R'
#define OPT_MCAST_TTL  '0'
#define OPT_MCAST_ADDR '1'
#define OPT_MCAST_PORT '2'
#define OPT_PCRE       '3'
#define OPT_PCRE_TEST  '4'
#define OPT_PORT_CHECK '5'
#define OPT_MCAST_SWITCH '6'
#define OPT_MTFTP      '7'
#define OPT_MTFTP_PORT '8'
#define OPT_TRACE      '9'

/*
 * Parse the command line using the standard getopt function.
 */
int tftpd_cmd_line_options(int argc, char **argv)
{
     int c;
     char *tmp;
#ifdef HAVE_PCRE
     char string[MAXLEN], out[MAXLEN];
#endif
     static struct option options[] = {
          { "tftpd-timeout", 1, NULL, 't' },
          { "retry-timeout", 1, NULL, 'r' },
          { "maxthread", 1, NULL, 'm' },
#ifdef RATE_CONTROL
          { "rate", 1, NULL, OPT_RATE },
#endif
          { "verbose", 2, NULL, 'v' },
          { "trace", 0, NULL, OPT_TRACE },
          { "no-timeout", 0, NULL, 'T' },
          { "no-tsize", 0, NULL, 'S' },
          { "no-blksize", 0, NULL, 'B' },
          { "no-multicast", 0, NULL, 'M' },
          { "logfile", 1, NULL, 'L' },
          { "pidfile", 1, NULL, 'I'},
          { "listen-local", 0, NULL, 'F'},
          { "daemon", 0, NULL, 'D' },
          { "no-fork", 0, NULL, 'N'},
          { "user", 1, NULL, 'U'},
          { "group", 1, NULL, 'G'},
          { "port", 1, NULL, 'P' },
          { "bind-address", 1, NULL, 'A'},
          { "mcast-ttl", 1, NULL, OPT_MCAST_TTL },
          { "mcast_ttl", 1, NULL, OPT_MCAST_TTL },
          { "mcast-addr", 1, NULL, OPT_MCAST_ADDR },
          { "mcast_addr", 1, NULL, OPT_MCAST_ADDR },
          { "mcast-port", 1, NULL, OPT_MCAST_PORT },
          { "mcast_port", 1, NULL, OPT_MCAST_PORT },
#ifdef HAVE_PCRE
          { "pcre", 1, NULL, OPT_PCRE },
          { "pcre-test", 1, NULL, OPT_PCRE_TEST },
#endif
#ifdef HAVE_MTFTP
          { "mtftp", 1, NULL, OPT_MTFTP },
          { "mtftp-port", 1, NULL, OPT_MTFTP_PORT },
#endif
          { "no-source-port-checking", 0, NULL, OPT_PORT_CHECK },
          { "mcast-switch-client", 0, NULL, OPT_MCAST_SWITCH },
          { "version", 0, NULL, 'V' },
          { "help", 0, NULL, 'h' },
          { 0, 0, 0, 0 }
     };
     
     while ((c = getopt_long(argc, argv, "t:r:m:v::Vh",
                             options, NULL)) != EOF)
     {
          switch (c)
          {
          case 't':
               tftpd_timeout = atoi(optarg);
               break;
          case 'r':
               retry_timeout = atoi(optarg);
               break;
          case 'm':
               tftpd_max_thread = atoi(optarg);
               break;
#ifdef RATE_CONTROL
          case OPT_RATE:
               rate = atoi(optarg);
               break;
#endif
          case 'v':
               if (optarg)
                    logging_level = atoi(optarg);
               else
                    logging_level++;
#ifdef HAVE_WRAP
               allow_severity = logging_level;
               deny_severity = logging_level;
#endif
               break;
          case OPT_TRACE:
               trace = 1;
               break;
          case 'T':
               tftp_default_options[OPT_TIMEOUT].enabled = 0;
               break;
          case 'S':
               tftp_default_options[OPT_TSIZE].enabled = 0;
               break;
          case 'B':
               tftp_default_options[OPT_BLKSIZE].enabled = 0;
               break;
          case 'M':
               tftp_default_options[OPT_MULTICAST].enabled = 0;
               break;
          case 'L':
               log_file = strdup(optarg);
               break;
          case 'I':
               pidfile = strdup(optarg);
               break;
          case 'F':
               listen_local = 1;
               break;
          case 'D':
               tftpd_daemon = 1;
               break;
          case 'N':
               tftpd_daemon_no_fork = 1;
               break;
          case 'U':
               tmp = strtok(optarg, ".");
               if (tmp != NULL)
                    Strncpy(user_name, tmp, MAXLEN);
               tmp = strtok(NULL, "");
               if (tmp != NULL)
                    Strncpy(group_name, optarg, MAXLEN);
               break;
          case 'G':
               Strncpy(group_name, optarg, MAXLEN);
               break;
          case 'P':
               tftpd_port = (short)atoi(optarg);
               break;
          case 'A': 
               Strncpy(tftpd_addr, optarg, MAXLEN);
               break;
          case OPT_MCAST_TTL:
               mcast_ttl = atoi(optarg);
               break;
          case OPT_MCAST_ADDR:
               Strncpy(mcast_addr, optarg, MAXLEN);
               break;
          case '2':
               Strncpy(mcast_port, optarg, MAXLEN);
               break;
#ifdef HAVE_PCRE
          case OPT_PCRE:
               pcre_file = strdup(optarg);
               break;
          case OPT_PCRE_TEST:
               /* test the pattern file */
               if ((pcre_top = tftpd_pcre_open(optarg)) == NULL)
               {
                    fprintf(stderr, "Failed to initialise PCRE with file %s", optarg);
                    exit(1);
               }
               /* run test */
               while (1)
               {
                    if (isatty(0))
                         printf("> ");
                    if (fgets(string, MAXLEN, stdin) == NULL)
                    {
                         tftpd_pcre_close(pcre_top);
                         exit(0);
                    }
                    /* exit on empty line */
                    if (string[0] == '\n')
                    {
                         tftpd_pcre_close(pcre_top);
                         exit(0);
                    }
                    /* remove \n from input */
                    string[strlen(string) - 1] = '\0';
                    /* do the substitution */
                    if (tftpd_pcre_sub(pcre_top, out, MAXLEN, string) < 0)
                         printf("Substitution: \"%s\" -> \"\"\n", string);
                    else
                         printf("Substitution: \"%s\" -> \"%s\"\n", string, out);
               }
#endif
          case OPT_PORT_CHECK:
               source_port_checking = 0;
               break;
          case OPT_MCAST_SWITCH:
               mcast_switch_client = 1;
               break;
#ifdef HAVE_MTFTP
          case OPT_MTFTP:
               Strncpy(mtftp_file, optarg, MAXLEN);         
               break;
          case OPT_MTFTP_PORT:
               mtftp_sport = atoi(optarg);
               break;
#endif
          case 'V':
               printf("atftp-%s (server)\n", VERSION);
               exit(0);
          case 'h':
               tftpd_usage();
               exit(0);
          case '?':
               exit(1);
               break;
          }
     }
          
     /* verify that only one arguement is left */
     if (optind < argc)
          Strncpy(directory, argv[optind], MAXLEN);
     /* make sure the last caracter is a / */
     if (directory[strlen(directory)] != '/')
          strcat(directory, "/");
     /* build multicast address/port range */
     if (tftpd_mcast_parse_opt(mcast_addr, mcast_port) != OK)
          exit(1);
     return OK;
}

/*
 * Output option to the syslog.
 */
void tftpd_log_options(void)
{
     if (tftpd_daemon == 1)
     {
          logger(LOG_INFO, "  running in daemon mode on port %d", tftpd_port);
          if (strlen(tftpd_addr) > 0)
               logger(LOG_INFO, "  bound to IP address %s only", tftpd_addr);
     }
     else
          logger(LOG_INFO, "  started by inetd");
     logger(LOG_INFO, "  logging level: %d", logging_level);
     if (trace)
          logger(LOG_INFO, "     trace enabled");
     logger(LOG_INFO, "  directory: %s", directory);
     logger(LOG_INFO, "  user: %s.%s", user_name, group_name);
     logger(LOG_INFO, "  log file: %s", (log_file==NULL) ? "syslog":log_file);
     if (pidfile)
          logger(LOG_INFO, "  pid file: %s", pidfile);
     if (listen_local == 1)
          logger(LOG_INFO, "  forcing to listen on local interfaces: on.");
     else
          logger(LOG_INFO, "  not forcing to listen on local interfaces.");
     if (tftpd_daemon == 1)
          logger(LOG_INFO, "  server timeout: Not used");
     else
          logger(LOG_INFO, "  server timeout: %d", tftpd_timeout);
     logger(LOG_INFO, "  tftp retry timeout: %d", retry_timeout);
     logger(LOG_INFO, "  maximum number of thread: %d", tftpd_max_thread);
#ifdef RATE_CONTROL
     if (rate > 0)
          logger(LOG_INFO, "  request per minute limit: %d", rate);
     else
          logger(LOG_INFO, "  request per minute limit: ---");
#endif
     logger(LOG_INFO, "  option timeout:   %s",
            tftp_default_options[OPT_TIMEOUT].enabled ? "enabled":"disabled");
     logger(LOG_INFO, "  option tzise:     %s",
            tftp_default_options[OPT_TSIZE].enabled ? "enabled":"disabled");
     logger(LOG_INFO, "  option blksize:   %s",
            tftp_default_options[OPT_BLKSIZE].enabled ? "enabled":"disabled");
     logger(LOG_INFO, "  option multicast: %s",
            tftp_default_options[OPT_MULTICAST].enabled ? "enabled":"disabled");
     logger(LOG_INFO, "     address range: %s", mcast_addr);
     logger(LOG_INFO, "     port range:    %s", mcast_port);
#ifdef HAVE_PCRE
     if (pcre_top)
          logger(LOG_INFO, "  PCRE: using file: %s", pcre_file);
#endif
#ifdef HAVE_MTFTP
     if (strcmp(mtftp_file, "") != 0)
     {
          logger(LOG_INFO, "  mtftp: using file: %s", mtftp_file);
          logger(LOG_INFO, "  mtftp: listenning on port %d", mtftp_sport);
     }
#endif
     if (mcast_switch_client)
          logger(LOG_INFO, "  --mcast-switch-client turned on");
     if (!source_port_checking)
          logger(LOG_INFO, "  --no-source-port-checking turned on");
}

/* 
 *
 */
int tftpd_pid_file(char *file, int action)
{
     FILE *fp;
     pid_t pid;

     if (action)
     {
          /* check if file exist */
          if ((fp = fopen(file, "r")) != NULL)
          {
               logger(LOG_NOTICE, "pid file already exist, overwriting");
               fclose(fp);
          }
          /* open file for writing */
          if ((fp = fopen(file, "w")) == NULL)
          {
               logger(LOG_ERR, "error writing PID to file %s\n", file);
               return ERR;
          }
          /* write it */
          pid = getpid();     
          fprintf(fp, "%d\n", pid);
          fclose(fp);
          return OK;
     }
     else
     {
          /* unlink the pid file */
          if (unlink(file) == -1)
               logger(LOG_ERR, "unlink: %s", strerror(errno));
          return OK;
     }
}

/*
 * Show a nice usage...
 */
void tftpd_usage(void)
{
     printf("Usage: tftpd [options] [directory]\n"
            " [options] may be:\n"
            "  -t, --tftpd-timeout <value>: number of second of inactivity"
            " before exiting\n"
            "  -r, --retry-timeout <value>: time to wait a reply before"
            " retransmition\n"
            "  -m, --maxthread <value>    : number of concurrent thread"
            " allowed\n"
#ifdef RATE_CONTROL
            "  --rate <value>             : number of request per minute limit\n"
#endif
            "  -v, --verbose [value]      : increase or set the level of"
            " output messages\n"
            "  --trace                    : log all sent and received packets\n"
            "  --no-timeout               : disable 'timeout' from RFC2349\n"
            "  --no-tsize                 : disable 'tsize' from RFC2349\n"
            "  --no-blksize               : disable 'blksize' from RFC2348\n"
            "  --no-multicast             : disable 'multicast' from RFC2090\n"
            "  --logfile <file>           : logfile to log logs to ;-)\n"
            "  --pidfile <file>           : write PID to this file\n"
            "  --listen-local             : force listen on local network address\n"
            "  --daemon                   : run atftpd standalone (no inetd)\n"
            "  --no-fork                  : run as a daemon, don't fork\n"
            "  --user <user[.group]>      : default is nobody\n"
            "  --group <group>            : default is nogroup\n"
            "  --port <port>              : port on which atftp listen\n"
            "  --bind-address <IP>        : local address atftpd listen to\n"
            "  --mcast-ttl                : ttl to used for multicast\n"
            "  --mcast-addr <address list>: list/range of IP address to use\n"
            "  --mcast-port <port range>  : ports to use for multicast"
            " transfer\n"
#ifdef HAVE_PCRE
            "  --pcre <file>              : use this file for pattern replacement\n"
            "  --pcre-test <file>         : just test pattern file, not starting server\n"
#endif
#ifdef HAVE_MTFTP
            "  --mtftp <file>             : mtftp configuration file\n"
            "  --mtftp-port <port>        : port mtftp will listen\n"
#endif
            "  --no-source-port-checking  : violate RFC, see man page\n"
            "  --mcast-switch-client      : switch client on first timeout, see man page\n"
            "  -V, --version              : print version information\n"
            "  -h, --help                 : print this help\n"
            "\n"
            " [directory] must be a world readable/writable directories.\n"
            " By default /tftpboot is assumed."
            "\n");
}