/* dgamelaunch.c
 *
 * (c)2001-3 M. Drew Streib <dtype@dtype.org>
 * also parts (c) 2003 Joshua Kwan <joshk@triplehelix.org>,
 * Brett Carrington <brettcar@segvio.org>,
 * Jilles Tjoelker <jilles@stack.nl>
 *
 * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/*
 * See this program in action at http://alt.org/nethack/
 *
 * This is a little wrapper for nethack (and soon other programs) that
 * will allow them to be run from a telnetd session, chroot, shed privs,
 * make a simple login, then play the game.
 *
 * By default, this thing is also statically compiled, and can thus be
 * run inside of a chroot jail itself if necessary.
 *
 * Yes, I know it is all global variables. Deal with it. The program
 * is very small.
 */

#define _GNU_SOURCE
#include "dgamelaunch.h"

/* a request from the author: please leave some remnance of
 * 'based on dgamelaunch version xxx' in any derivative works, or
 * even keep the line the same altogether. I'm probably happy 
 * to make any changes you need. */

/* ************************************************************* */
/* ************************************************************* */
/* ************************************************************* */

/* program stuff */

#include <stdlib.h>
#include <curses.h>
#include <sys/types.h>
#include <sys/file.h>           /* for flock() */
#include <sys/time.h>

#ifndef __FreeBSD__
# include <crypt.h>
#else
# include <libutil.h>
#endif

#ifdef __linux__
# include <pty.h>
#endif

#ifndef ARRAY_SIZE
# define ARRAY_SIZE(x) sizeof(x) / sizeof(x[0])
#endif

#include <pwd.h>
#include <grp.h>
#include <time.h>
#include <sys/resource.h>
#include <sys/ioctl.h>          /* ttyrec */
#include <errno.h>
#include <dirent.h>
#include <string.h>
#include <sys/stat.h>
#include <signal.h>
#include <assert.h>
#include <ctype.h>
#include <unistd.h>
#include <termios.h>

#include "y.tab.h"
extern FILE* yyin;
extern int yyparse ();

extern int vi_main (int argc, char **argv);
extern int ttyplay_main (char *ttyfile, int mode, int rstripgfx);
extern int ttyrec_main (char *);
extern int master;
extern int slave;
extern struct termios tt;
extern struct winsize win;

/* global variables */

struct dg_config *myconfig = NULL;
char* config = NULL;

struct dg_config defconfig = {
  "/var/lib/dgamelaunch/",
  "/bin/nethack",
  "/dgldir/",
  "/dgl-banner",
  "/dgl-default-rcfile",
  "/var/mail/",
  "games", "games",
  5, 60, /* games:games in Debian */
  64000 
};

int pid_game = 0;
int loggedin = 0;
char rcfilename[80];
char ttyrec_filename[100];
char *chosen_name;

int f_num = 0;
struct dg_user **users = NULL;
struct dg_user *me = NULL;
struct dg_banner banner;

void
create_config ()
{
  FILE *config_file = NULL;

  if (config)
  {
    if ((config_file = fopen(config, "r")) != NULL)
    {
      yyin = config_file;
      yyparse();
      fclose(config_file);
      free (config);
    }

    /* Fill the rest with defaults */
    if (!myconfig->shed_user && myconfig->shed_uid == 0)
    {
      struct passwd *pw;
      if ((pw = getpwnam(defconfig.shed_user)))
        myconfig->shed_uid = pw->pw_uid;
      else
	myconfig->shed_uid = defconfig.shed_uid;
    }

    if (!myconfig->shed_group && myconfig->shed_gid == 0)
    {
      struct group *gr;
      if ((gr = getgrnam(defconfig.shed_group)))
	myconfig->shed_gid = gr->gr_gid;
      else
	myconfig->shed_gid = defconfig.shed_gid;
    }

    if (myconfig->max == 0) myconfig->max = defconfig.max;
    if (!myconfig->banner) myconfig->banner = strdup(defconfig.banner);
    if (!myconfig->chroot) myconfig->chroot = strdup(defconfig.chroot);
    if (!myconfig->nethack) myconfig->nethack = strdup(defconfig.nethack);
    if (!myconfig->dglroot) myconfig->dglroot = strdup(defconfig.dglroot);
    if (!myconfig->rcfile) myconfig->rcfile = strdup(defconfig.rcfile);
    if (!myconfig->spool) myconfig->spool = strdup(defconfig.spool);
  }
  else
  {
    myconfig = &defconfig;
  }
}

/* ************************************************************* */
/* for ttyrec */


void
ttyrec_getmaster ()
{
  (void) tcgetattr (0, &tt);
  (void) ioctl (0, TIOCGWINSZ, (char *) &win);
#ifdef USE_OPENPTY
  if (openpty (&master, &slave, NULL, &tt, &win) == -1)
#else
  if ((master = open ("/dev/ptmx", O_RDWR)) < 0)
#endif
    graceful_exit (62);
}

/* ************************************************************* */

void
gen_ttyrec_filename ()
{
  time_t rawtime;
  struct tm *ptm;

  /* append time to filename */
  time (&rawtime);
  ptm = gmtime (&rawtime);
  snprintf (ttyrec_filename, 100, "%04i-%02i-%02i.%02i:%02i:%02i.ttyrec",
            ptm->tm_year + 1900, ptm->tm_mon + 1, ptm->tm_mday,
            ptm->tm_hour, ptm->tm_min, ptm->tm_sec);
}

/* ************************************************************* */

void
gen_inprogress_lock (pid_t pid)
{
  char lockfile[130], pidbuf[16];
  int fd;
  struct flock fl = { 0 };

  snprintf (pidbuf, 16, "%d", pid);

  fl.l_type = F_WRLCK;
  fl.l_whence = SEEK_SET;
  fl.l_start = 0;
  fl.l_len = 0;

  snprintf (lockfile, 130, "%sinprogress/%s:%s", myconfig->dglroot,
            me->username, ttyrec_filename);

  fd = open (lockfile, O_WRONLY | O_CREAT, 0644);
  if (fcntl (fd, F_SETLKW, &fl) == -1)
    graceful_exit (68);

  write (fd, pidbuf, strlen (pidbuf));
}

/* ************************************************************* */

void
catch_sighup (int signum)
{
  if (pid_game)
    {
      sleep (10);
      kill (pid_game, SIGHUP);
      sleep (5);
    }
  graceful_exit (2);
}

/* ************************************************************* */

void
loadbanner (struct dg_banner *ban)
{
  FILE *bannerfile;
  char buf[80];

  memset (buf, 0, 80);

  bannerfile = fopen (myconfig->banner, "r");

  if (!bannerfile)
    {
      size_t len;
      ban->len = 2;
      ban->lines = malloc (sizeof (char *));
      ban->lines[0] =
        strdup ("### dgamelaunch " VERSION
                " - network console game launcher");
      len = strlen(myconfig->banner) + ARRAY_SIZE("### NOTE: administrator has not installed a  file");
      ban->lines[1] = malloc(len);
      snprintf(ban->lines[1], len, "### NOTE: administrator has not installed a %s file", myconfig->banner);
      return;
    }

  ban->len = 0;

  while (fgets (buf, 80, bannerfile) != NULL)
    {
      char *loc;

      ban->len++;
      ban->lines = realloc (ban->lines, sizeof (char *) * ban->len);

      if ((loc = strstr (buf, "$VERSION")) != NULL)
        {
          char bufnew[80];
          char *b = buf;
          int i;

          memset (bufnew, 0, 80);

          for (i = 0; i < 80; i++)
            {
              if (loc != b)
                bufnew[i] = *(b++);
              else
                {
                  strlcat (bufnew, VERSION, 80 - i);
                  b += 8;       /* skip the whole $VERSION string */
                  i += ARRAY_SIZE (VERSION);
                }

              if (strlen (b) == 0)
                break;
            }

          ban->lines[ban->len - 1] = strdup (bufnew);
        }
      else
        ban->lines[ban->len - 1] = strdup (buf);

      memset (buf, 0, 80);

      if (ban->len == 14)       /* menu itself needs 10 lines, 24 - 10 */
        break;
    }

  fclose (bannerfile);
}

void
drawbanner (unsigned int start_line, unsigned int howmany)
{
  static short loaded_banner = 0;
  unsigned int i;

  if (!loaded_banner)
    {
      loadbanner (&banner);
      loaded_banner = 1;
    }

  if (howmany > banner.len || howmany == 0)
    howmany = banner.len;

  for (i = 0; i < howmany; i++)
    mvaddstr (start_line + i, 1, banner.lines[i]);
}

struct dg_game **
populate_games (int *l)
{
  int fd, len;
  DIR *pdir;
  struct dirent *pdirent;
  struct stat pstat;
  char fullname[130], ttyrecname[130];
  char *replacestr, *dir;
  struct dg_game **games = NULL;
  struct flock fl = { 0 };
  size_t slen;

  fl.l_type = F_WRLCK;
  fl.l_whence = SEEK_SET;
  fl.l_start = 0;
  fl.l_len = 0;

  len = 0;
  
  slen = strlen(myconfig->dglroot) + ARRAY_SIZE("inprogress/") + 1;
  dir = malloc(slen);
  snprintf(dir, slen, "%sinprogress/", myconfig->dglroot);

  if (!(pdir = opendir (dir)))
    graceful_exit (140);

  while ((pdirent = readdir (pdir)))
    {
      if (!strcmp (pdirent->d_name, ".") || !strcmp (pdirent->d_name, ".."))
        continue;

      snprintf (fullname, 130, "%sinprogress/%s", myconfig->dglroot, pdirent->d_name);

      fd = 0;
      /* O_RDWR here should be O_RDONLY, but we need to test for
       * an exclusive lock */
      fd = open (fullname, O_RDWR);
      if ((fd > 0) && fcntl (fd, F_SETLK, &fl) == -1)
        {

          /* stat to check idle status */
          snprintf (ttyrecname, 130, "%sttyrec/%s", myconfig->dglroot, pdirent->d_name);
          replacestr = strchr (ttyrecname, ':');
          if (!replacestr)
            graceful_exit (145);
          replacestr[0] = '/';
          if (!stat (ttyrecname, &pstat))
            {
              /* now it's a valid game for sure */
              games = realloc (games, sizeof (struct dg_game) * (len + 1));
              games[len] = malloc (sizeof (struct dg_game));
              games[len]->ttyrec_fn = strdup (pdirent->d_name);

              if (!(replacestr = strchr (pdirent->d_name, ':')))
                graceful_exit (146);
              else
                *replacestr = '\0';

              games[len]->name = malloc (strlen (pdirent->d_name) + 1);
              strlcpy (games[len]->name, pdirent->d_name,
                       strlen (pdirent->d_name) + 1);

              games[len]->date = malloc (11);
              strlcpy (games[len]->date, replacestr + 1, 11);

              games[len]->time = malloc (9);
              strlcpy (games[len]->time, replacestr + 12, 9);

              games[len]->idle_time = pstat.st_mtime;

              len++;
            }
        }
      else
        {
          /* clean dead ones */
          unlink (fullname);
        }
      fl.l_type = F_UNLCK;

      fcntl (fd, F_SETLK, &fl);
      close (fd);
    }

  closedir (pdir);
  *l = len;
  return games;
}


void
inprogressmenu ()
{
  int i, menuchoice, len = 20, offset = 0;
  time_t ctime;
  struct dg_game **games;
  char ttyrecname[130], *replacestr = NULL;

  games = populate_games (&len);

  while (1)
    {
      clear ();
      drawbanner (1, 1);
      mvprintw (3, 1,
                "During playback, hit 'q' to return here%s.",
                loggedin ? ", 'm' to contact the player" : "");
      mvaddstr (4, 1,
                "(Use capital letter of selection to strip DEC graphics, VERY experimental!)");
      mvaddstr (5, 1, "The following games are in progress:");

      /* clean old games and list good ones */
      i = 0;

      for (i = 0; i < 14; i++)
        {
          if (i + offset >= len)
            break;

          mvprintw (7 + i, 1, "%c) %-15s %s %s (%ldm %lds idle)",
                    i + 97, games[i + offset]->name,
                    games[i + offset]->date, games[i + offset]->time,
                    (time (&ctime) - games[i + offset]->idle_time) / 60,
                    (time (&ctime) - games[i + offset]->idle_time) % 60);
        }

      mvaddstr (23, 1,
                "Watch which game? (r refreshes, q quits, >/< for more/less) => ");
      refresh ();

      switch ((menuchoice = tolower (getch ())))
        {
        case '>':
          if ((offset + 14) >= len)
            break;
          else
            offset += 14;
          break;

        case '<':
          if ((offset - 14) < 0)
            break;
          else
            offset -= 14;
          break;

        case 'q':
          return;

        default:
          if ((menuchoice - 97) >= 0 && (menuchoice - 97) < i)
            {
              /* valid choice has been made */
              snprintf (ttyrecname, 130, "%sttyrec/%s", myconfig->dglroot,
                        games[menuchoice - 97]->ttyrec_fn);
              chosen_name = strdup (games[menuchoice - 97 + offset]->name);

              /* reuse thie char* */
              replacestr = strchr (ttyrecname, ':');

              if (!replacestr)
                graceful_exit (145);

              replacestr[0] = '/';

              clear ();
              refresh ();
              endwin ();
              ttyplay_main (ttyrecname, 1, 0);
              initncurses ();
            }
        }

      games = populate_games (&len);
    }
}

/* ************************************************************* */

int
changepw ()
{
  char buf[21];
  int error = 2;

  /* A precondition is that struct `me' exists because we can be not-yet-logged-in. */
  if (!me)
    graceful_exit (122);        /* Die. */

  while (error)
    {
      char repeatbuf[21];
      clear ();

      drawbanner (1, 1);

      mvprintw (5, 1,
                "Please enter a%s password. Remember that this is sent over the net",
                loggedin ? " new" : "");
      mvaddstr (6, 1,
                "in plaintext, so make it something new and expect it to be relatively");
      mvaddstr (7, 1, "insecure.");
      mvaddstr (8, 1,
                "20 character max. No ':' characters. Blank line to abort.");
      mvaddstr (10, 1, "=> ");

      if (error == 1)
        {
          mvaddstr (15, 1, "Sorry, the passwords don't match. Try again.");
          move (10, 4);
        }

      refresh ();

      noecho ();
      getnstr (buf, 20);
      echo ();                  /* Putting echo back on just for safety and because it can't hurt. */

      if (buf && *buf == '\0')
        return 0;

      if (strchr (buf, ':') != NULL)
        graceful_exit (112);

      mvaddstr (12, 1, "And again:");
      mvaddstr (13, 1, "=> ");

      noecho ();
      getnstr (repeatbuf, 20);
      echo ();                  /* Here is the important echo(); if the former is removed. */

      if (!strcmp (buf, repeatbuf))
        error = 0;
      else
        error = 1;
    }

  me->password = strdup (crypt (buf, buf));
  writefile (0);

  return 1;
}

/* ************************************************************* */

void
domailuser (char *username)
{
  unsigned int len, i;
  char *spool_fn, message[80];
  FILE *user_spool = NULL;
  time_t now;
  int mail_empty = 1;
  struct flock fl = { 0 };

  fl.l_type = F_WRLCK;
  fl.l_whence = SEEK_SET;
  fl.l_start = 0;
  fl.l_len = 0;

  assert (loggedin);

  len = strlen(myconfig->spool) + strlen (username) + 1;
  spool_fn = malloc (len + 1);
  time (&now);
  snprintf (spool_fn, len, "%s/%s", myconfig->spool, username);

  /* print the enter your message line */
  clear ();
  drawbanner (1, 1);
  mvaddstr (5, 1,
            "Enter your message here. It is to be one line only and 80 characters or less.");
  mvaddstr (7, 1, "=> ");

  getnstr (message, 80);

  for (i = 0; i < strlen (message); i++)
    {
      if (message[i] != ' ' && message[i] != '\n' && message[i] != '\t')
        mail_empty = 0;
    }

  if (mail_empty)
    {
      mvaddstr (9, 1, "This scroll appears to be blank.--More--");
      mvaddstr (10, 1, "(Aborting your message.)");
      getch ();
      return;
    }

  if ((user_spool = fopen (spool_fn, "a")) == NULL)
    {
      mvaddstr (9, 1,
                "You fall into the water! You sink like a rock.--More--");
      mvprintw (10, 1,
                "(I couldn't open %s'%c spool file for some reason, so I'm giving up.)",
                username, (username[strlen (username) - 1] != 's') ? 's' : 0);
      getch ();
      return;
    }

  mvaddstr (9, 1, "Getting a lock on the mailspool...");
  refresh ();

  while (fcntl (fileno (user_spool), F_SETLK, &fl) == -1)
    {
      if (errno != EAGAIN)
        {
          mvaddstr (10, 1,
                    "Received a weird error from fcntl, so I'm giving up.");
          getch ();
          return;
        }
      sleep (1);
    }

  fprintf (user_spool, "%s:%s\n", me->username, message);

  fl.l_type = F_UNLCK;

  if (fcntl (fileno (user_spool), F_SETLK, &fl) == -1)
    mvaddstr (10, 1, "Couldn't unlock the file! Oh well.");

  fclose (user_spool);

  return;
}

void
drawmenu ()
{
  static int flood = 0;

  clear ();

  drawbanner (1, 0);

  if (loggedin)
    {
      mvprintw (banner.len + 2, 1, "Logged in as: %s", me->username);
      mvaddstr (banner.len + 4, 1, "c) Change password");
      mvaddstr (banner.len + 5, 1, "o) Edit option file (requires vi use)");
      mvaddstr (banner.len + 6, 1, "w) Watch games in progress");
      mvaddstr (banner.len + 7, 1, "p) Play nethack!");
      mvaddstr (banner.len + 8, 1, "q) Quit");
      mvaddstr (banner.len + 10, 1, "=> ");
    }
  else
    {
      mvaddstr (banner.len + 2, 1, "Not logged in.");
      mvaddstr (banner.len + 4, 1, "l) Login");
      mvaddstr (banner.len + 5, 1, "r) Register new user");
      mvaddstr (banner.len + 6, 1, "w) Watch games in progress");
      mvaddstr (banner.len + 7, 1, "q) Quit");
      mvaddstr (banner.len + 9, 1, "=> ");
    }

  refresh ();

  /* for retarded clients */
  flood++;
  if (flood >= 20)
  {
    endwin();
    graceful_exit (119);
  }
}

/* ************************************************************* */

void
freefile ()
{
  int i;

  /* free existing mem, clear existing entries */
  for (i = 0; i < f_num; i++)
    {
      free (users[i]->password);
      free (users[i]->username);
      free (users[i]->email);
      free (users[i]->env);
      free (users[i]);
    }

  if (users)
    free (users);

  users = NULL;
  f_num = 0;
}

/* ************************************************************* */

void
initncurses ()
{
  initscr ();
  cbreak ();
  echo ();
  nonl ();
  intrflush (stdscr, FALSE);
  keypad (stdscr, TRUE);
}

/* ************************************************************* */

struct dg_user *
deep_copy (struct dg_user *src)
{
  struct dg_user *dest = malloc (sizeof (struct dg_user));

  dest->username = strdup (src->username);
  dest->email = strdup (src->email);
  dest->env = strdup (src->env);
  dest->password = strdup (src->password);
  dest->flags = src->flags;

  return dest;
}

void
loginprompt ()
{
  char user_buf[22], pw_buf[22];
  int error = 2, me_index = -1;

  loggedin = 0;

  while (error)
    {
      clear ();

      drawbanner (1, 1);

      mvaddstr (5, 1,
                "Please enter your username. (blank entry returns to main menu)");
      mvaddstr (7, 1, "=> ");

      if (error == 1)
        {
          mvaddstr (9, 1, "There was a problem with your last entry.");
          move (7, 4);
        }

      refresh ();

      getnstr (user_buf, 20);

      if (user_buf && *user_buf == '\0')
        return;

      error = 1;

      if ((me_index = userexist (user_buf)) != -1)
        {
          me = deep_copy (users[me_index]);
          error = 0;
        }
    }

  clear ();

  drawbanner (1, 1);

  mvaddstr (5, 1, "Please enter your password.");
  mvaddstr (7, 1, "=> ");

  refresh ();

  noecho ();
  getnstr (pw_buf, 20);
  echo ();

  if (passwordgood (pw_buf))
    {
      loggedin = 1;
      snprintf (rcfilename, 80, "%srcfiles/%s.nethackrc", myconfig->dglroot, me->username);
    }
}

/* ************************************************************* */

void
newuser ()
{
  char buf[1024];
  int error = 2;
  unsigned int i;

  loggedin = 0;

  if (me)
    free (me);

  me = malloc (sizeof (struct dg_user));

  while (error)
    {
      clear ();

      drawbanner (1, 1);

      mvaddstr (5, 1, "Welcome new user. Please enter a username.");
      mvaddstr (6, 1,
                "Only characters and numbers are allowed, with no spaces.");
      mvaddstr (7, 1, "20 character max.");
      mvaddstr (9, 1, "=> ");

      if (error == 1)
        {
          mvaddstr (11, 1, "There was a problem with your last entry.");
          move (9, 4);
        }

      refresh ();

      getnstr (buf, 20);
      if (userexist (buf) == -1)
        error = 0;
      else
        error = 1;

      for (i = 0; i < strlen (buf); i++)
        {
          if (!isalnum(buf[i]))
            error = 1;
        }

      if (strlen (buf) < 2)
        error = 1;

      if (strlen (buf) == 0)
      {
	free(me);
        return;
      }
    }

  me->username = strdup (buf);

  /* password step */

  clear ();

  if (!changepw ())                  /* Calling changepw instead to prompt twice. */
  {
    free(me->username);
    free(me);
    me = NULL;
    return;
  }

  /* email step */

  clear ();

  drawbanner (1, 1);

  mvaddstr (5, 1, "Please enter your email address.");
  mvaddstr (6, 1,
            "This is sent _nowhere_ but will be used if you ask the sysadmin for lost");
  mvaddstr (7, 1,
            "password help. Please use a correct one. It only benefits you.");
  mvaddstr (8, 1, "80 character max. No ':' characters. Blank line aborts.");
  mvaddstr (10, 1, "=> ");

  refresh ();
  getnstr (buf, 80);

  if (strchr (buf, ':') != NULL)
    graceful_exit (113);

  if (buf && *buf == '\0')
  {
    free (me->username);
    free (me->password);
    free (me);
    me = NULL;
    return;
  }

  me->email = strdup (buf);
  me->env = calloc (1, 1);

  loggedin = 1;

  snprintf (rcfilename, 80, "%srcfiles/%s.nethackrc", myconfig->dglroot, me->username);
  write_canned_rcfile (rcfilename);

  writefile (1);
}

/* ************************************************************* */

int
passwordgood (char *cpw)
{
  if (me == NULL)
    return 1;

  if (!strncmp (crypt (cpw, cpw), me->password, 13))
    return 1;
  if (!strncmp (cpw, me->password, 20))
    return 1;

  return 0;
}

/* ************************************************************* */

int
readfile (int nolock)
{
  FILE *fp = NULL, *fpl = NULL;
  char buf[1200];
  struct flock fl;

  fl.l_type = F_RDLCK;
  fl.l_whence = SEEK_SET;
  fl.l_start = 0;
  fl.l_len = 0;

  memset (buf, 1024, 0);

  /* read new stuff */

  if (!nolock)
    {
      fpl = fopen ("/dgl-lock", "r");
      if (!fpl)
        graceful_exit (106);
      if (fcntl (fileno (fpl), F_SETLKW, &fl) == -1)
        graceful_exit (114);
    }

  fp = fopen ("/dgl-login", "r");
  if (!fp)
    graceful_exit (106);

  /* once per name in the file */
  while (fgets (buf, 1200, fp))
    {
      char *b = buf, *n = buf;

      users = realloc (users, sizeof (struct dg_user *) * (f_num + 1));
      users[f_num] = malloc (sizeof (struct dg_user));
      users[f_num]->username = (char *) calloc (22, sizeof (char));
      users[f_num]->email = (char *) calloc (82, sizeof (char));
      users[f_num]->password = (char *) calloc (22, sizeof (char));
      users[f_num]->env = (char *) calloc (1026, sizeof (char));

      /* name field, must be valid */
      while (*b != ':')
        {
          if (!isalnum(*b))
            return 1;
          users[f_num]->username[(b - n)] = *b;
          b++;
          if ((b - n) >= 21)
            graceful_exit (100);
        }

      /* advance to next field */
      n = b + 1;
      b = n;

      /* email field */
      while (*b != ':')
        {
          users[f_num]->email[(b - n)] = *b;
          b++;
          if ((b - n) > 80)
            graceful_exit (101);
        }

      /* advance to next field */
      n = b + 1;
      b = n;

      /* pw field */
      while (*b != ':')
        {
          users[f_num]->password[(b - n)] = *b;
          b++;
          if ((b - n) >= 20)
            graceful_exit (102);
        }

      /* advance to next field */
      n = b + 1;
      b = n;

      /* env field */
      while ((*b != '\n') && (*b != 0) && (*b != EOF))
        {
          users[f_num]->env[(b - n)] = *b;
          b++;
          if ((b - n) >= 1024)
            graceful_exit (102);
        }

      f_num++;
      /* prevent a buffer overrun here */
      if (f_num >= MAXUSERS)
        graceful_exit (109);
    }

  if (!nolock)
    {
      flock (fileno (fpl), LOCK_UN);
      fclose (fpl);
    }
  fclose (fp);
  return 0;
}

/* ************************************************************* */

int
userexist (char *cname)
{
  int i;

  for (i = 0; i < f_num; i++)
    {
      if (!strncasecmp (cname, users[i]->username, 20))
        return i;
    }

  return -1;
}

/* ************************************************************* */

void
write_canned_rcfile (char *target)
{
  FILE *canned, *newfile;
  char buf[1024], *rfn;
  size_t bytes, len;

  len = strlen(myconfig->dglroot) + strlen(myconfig->rcfile) + 1;
  rfn = malloc(len);
  snprintf (rfn, len, "%s%s", myconfig->dglroot, myconfig->rcfile);

  if (!(newfile = fopen (target, "w")))
    {
    bail:
      mvaddstr (13, 1,
                "You don't know how to write that! You write \"%s\" was here and the scroll disappears.");
      mvaddstr (14, 1,
                "(Sorry, but I couldn't open one of the nethackrc files. This is a bug.)");
      return;
    }

  if (!(canned = fopen (rfn, "r")))
    goto bail;

  free(rfn);

  while ((bytes = fread (buf, 1, 1024, canned)) > 0)
    {
      if (fwrite (buf, 1, bytes, newfile) != bytes)
        {
          if (ferror (newfile))
            {
              mvaddstr (13, 1, "Your hand slips while engraving.");
              mvaddstr (14, 1,
                        "(Encountered a problem writing the new file. This is a bug.)");
              fclose (canned);
              fclose (newfile);
              return;
            }
        }
    }

  fclose (canned);
  fclose (newfile);
}


void
editoptions ()
{
  FILE *rcfile;
  char *myargv[3];

  rcfile = fopen (rcfilename, "r");
  printf (" read");
  if (!rcfile)                  /* should not really happen except for old users */
    write_canned_rcfile (rcfilename);

  /* use virus to edit */

  myargv[0] = "";
  myargv[1] = rcfilename;
  myargv[2] = 0;

  endwin ();
  vi_main (2, myargv);
  refresh ();
}

/* ************************************************************* */

void
writefile (int requirenew)
{
  FILE *fp, *fpl;
  int i = 0;
  int my_done = 0;

  fpl = fopen ("/dgl-lock", "r");
  if (!fpl)
    graceful_exit (115);
  if (flock (fileno (fpl), LOCK_EX))
    graceful_exit (107);

  freefile ();
  readfile (1);

  fp = fopen ("/dgl-login", "w");
  if (!fp)
    graceful_exit (104);

  for (i = 0; i < f_num; i++)
    {
      if (loggedin && !strncasecmp (me->username, users[i]->username, 20))
        {
          if (requirenew)
            {
              /* this is if someone managed to register at the same time
               * as someone else. just die. */
              graceful_exit (111);
            }
          fprintf (fp, "%s:%s:%s:%s\n", me->username, me->email, me->password,
                   me->env);
          my_done = 1;
        }
      else
        {
          fprintf (fp, "%s:%s:%s:%s\n", users[i]->username, users[i]->email,
                   users[i]->password, users[i]->env);
        }
    }
  if (loggedin && !my_done)
    {                           /* new entry */
      fprintf (fp, "%s:%s:%s:%s\n", me->username, me->email, me->password,
               me->env);
    }

  flock (fileno (fpl), LOCK_UN);
  fclose (fp);
  fclose (fpl);
}

/* ************************************************************* */

void
graceful_exit (int status)
{
  /*FILE *fp;
     if (status != 1) 
     { 
     fp = fopen ("/crash.log", "a");
     char buf[100];
     sprintf (buf, "graceful_exit called with status %d", status);
     fputs (buf, fp);
     } 
     This doesn't work. Ever.
   */
  exit (status);
}


/* ************************************************************* */

/* ************************************************************* */
/* ************************************************************* */
/* ************************************************************* */


/* TODO: Some of the messages here (sorry no nethack for you!) are nethack specific
 * as may be some code... don't think so though. Globalize it. */ 
void
purge_stale_locks (void)
{
  DIR *pdir;
  struct dirent *dent;
  char* dir;
  size_t len;

  len = strlen(myconfig->dglroot) + ARRAY_SIZE("inprogress/") + 1;
  dir = malloc(len);
  snprintf(dir, len, "%sinprogress/", myconfig->dglroot);
  
  
  if (!(pdir = opendir (dir)))
    graceful_exit (200);

  free(dir);

  while ((dent = readdir (pdir)) != NULL)
    {
      FILE *ipfile;
      char *colon, *fn;
      char buf[16];
      pid_t pid;
      size_t len;
      int seconds = 0;

      if (!strcmp (dent->d_name, ".") || !strcmp (dent->d_name, ".."))
        continue;

      colon = strchr (dent->d_name, ':');
      /* should never happen */
      if (!colon)
        graceful_exit (201);

      if (strncmp (dent->d_name, me->username, colon - dent->d_name))
        continue;

      len = strlen (dent->d_name) + strlen(myconfig->dglroot) + 12;
      fn = malloc (len);

      snprintf (fn, len, "%sinprogress/%s", myconfig->dglroot, dent->d_name);

      if (!(ipfile = fopen (fn, "r")))
        graceful_exit (202);

      if (fgets (buf, 16, ipfile) == NULL)
        graceful_exit (203);

      fclose (ipfile);

      clear ();
      drawbanner (1, 1);
      mvaddstr (3, 1,
                "There is a stale Nethack process, attempting to recover...");
      refresh ();

      pid = atoi (buf);

      kill (pid, SIGHUP);

      errno = 0;

      /* Wait for it to stop running */
      seconds = 0;
      while (kill (pid, 0) == 0)
        {
          seconds++;
          sleep (1);
          if (seconds == 10)
            {
              mvaddstr (3, 1,
                        "Couldn't terminate one of your stale Nethack processes gracefully.");
              mvaddstr (4, 1, "Force its termination? [yn] ");
              if (tolower (getch ()) == 'y')
                {
                  kill (pid, SIGTERM);
                  break;
                }
              else
                {
                  endwin ();
                  fprintf (stderr, "Sorry, no nethack for you now, please "
                           "contact the admin.\n");
                  graceful_exit (1);
                }
            }
        }

      /* Don't remove the lock file until the process is dead. */
      unlink (fn);
      free (fn);
    }

  closedir (pdir);
}

int
main (int argc, char** argv)
{
  /* for chroot and program execution */
  char atrcfilename[81], *spool;
  unsigned int len;
  struct rlimit rl = { RLIM_INFINITY, RLIM_INFINITY };

  int userchoice = 0;

  if (argc == 2)
    config = strdup(argv[1]);
  
  create_config();

  /* coredumper */
  setrlimit (RLIMIT_CORE, &rl);

  /* signal handlers */
  signal (SIGHUP, catch_sighup);

  /* get master tty just before chroot (lives in /dev) */
  ttyrec_getmaster ();
#ifndef USE_OPENPTY
  grantpt (master);
  unlockpt (master);
  if ((slave = open ((const char *) ptsname (master), O_RDWR)) < 0)
    {
      graceful_exit (65);
    }
#endif


  /* chroot */
  if (chroot (myconfig->chroot))
    {
      perror ("cannot change root directory");
      graceful_exit (1);
    }

  if (chdir ("/"))
    {
      perror ("cannot chdir to root directory");
      graceful_exit (1);
    }

  /* shed privs. this is done immediately after chroot. */
  if (setgroups (1, &myconfig->shed_gid) == -1)
    {
      perror ("setgroups");
      graceful_exit (1);
    }

  if (setgid (myconfig->shed_gid) == -1)
    {
      perror ("setgid");
      graceful_exit (1);
    }

  if (setuid (myconfig->shed_uid) == -1)
    {
      perror ("setuid");
      graceful_exit (1);
    }

  /* simple login routine, uses ncurses */
  if (readfile (0))
    graceful_exit (110);

  initncurses ();
  while ((userchoice != 'p') | (!loggedin))
    {
      drawmenu ();
      userchoice = getch ();
      switch (tolower (userchoice))
        {
        case 'c':
          if (loggedin)
            changepw ();
          break;
        case 'w':
          inprogressmenu ();
          break;
        case 'o':
          if (loggedin)
            editoptions ();
          break;
        case 'q':
          endwin ();
          return 0;
          /* break; */
        case 'r':
          if (!loggedin)        /*not visible to loggedin */
            newuser ();
          break;
        case 'l':
          if (!loggedin)        /* not visible to loggedin */
            loginprompt ();
          break;
        }
    }

  assert (loggedin);

  purge_stale_locks ();

  endwin ();

  /* environment */
  snprintf (atrcfilename, 81, "@%s", rcfilename);

  len = strlen(myconfig->spool) + strlen (me->username) + 1;
  spool = malloc (len + 1);
  snprintf (spool, len, "%s/%s", myconfig->spool, me->username);

  setenv ("NETHACKOPTIONS", atrcfilename, 1);
  setenv ("MAIL", spool, 1);
  setenv ("SIMPLEMAIL", "1", 1);

  /* don't let the mail file grow */
  if (access (spool, F_OK) == 0)
    unlink (spool);

  free (spool);

  /* lock */
  gen_ttyrec_filename ();

  /* launch program */
  ttyrec_main (me->username);

  /* NOW we can safely kill this */
  freefile ();

  if (me)
    free (me);

  graceful_exit (1);
  return 1;
}