--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/webttyd.js	Sun May 06 08:45:40 2012 -0700
@@ -0,0 +1,531 @@
+#!/usr/bin/env node
+
+// If you can't quite trust node to find it on its own
+var localModules = '/usr/local/lib/node_modules/';
+var http = require('http');
+var url = require('url');
+var path = require('path');
+var fs = require('fs');
+//var tty = require("tty");
+var child_process = require('child_process');
+var daemon = require(path.join(localModules, "daemon"));
+
+var chrootDir = "/var/dgl/";
+var dropToUID = 501;
+var dropToGID = 501;
+var serveStaticRoot = "/var/www/"; // inside the chroot
+var passwdfile = "/dgldir/dgl-login";
+var sessions = {};
+
+var games = {
+  "rogue3": {
+    "name": "Rogue V3",
+    "uname": "rogue3",
+    "path": "/bin/rogue3"
+  },
+  "rogue4": {
+    "name": "Rogue V4",
+    "uname": "rogue4",
+    "path": "/bin/rogue4"
+  },
+  "rogue5": {
+    "name": "Rogue V5",
+    "uname": "rogue5",
+    "path": "/bin/rogue5"
+  },
+  "srogue": {
+    "name": "Super-Rogue",
+    "uname": "srogue",
+    "path": "/bin/srogue"
+  }
+};
+
+/* Constructor for TermSessions.  Note that it opens the terminal and 
+ * adds itself to the sessions dict. It currently assumes the user has
+ * been authenticated.
+ */
+function TermSession(game, user, files) {
+  /* First make sure starting the game will work. */
+  if (!(game in games)) {
+    // TODO: throw an exception instead
+    return null;
+  }
+  /* This order seems to best avoid race conditions... */
+  this.alive = false;
+  this.sessid = randkey();
+  while (this.sessid in sessions) {
+    this.sessid = randkey();
+  }
+  /* Grab a spot in the sessions table. */
+  sessions[this.sessid] = this;
+  /* TODO handle tty-opening errors */
+  //var pterm = tty.open(games[game].path, ["-n", user.toString()]);
+  /* TODO make argument-finding into a method */
+  args = [games[game].path, "-n", user.toString()];
+  this.child = child_process.spawn("/bin/ptyhelper", args);
+  var ss = this;
+  //this.ptmx = pterm[0];
+  //this.child = pterm[1];
+  this.alive = true;
+  this.data = [];
+  this.lock = files[0];
+  fs.writeFile(this.lock, this.child.pid.toString() + '\n80\n24\n', "utf8"); 
+  this.record = fs.createWriteStream(files[1], { mode: 0664 });
+  /* END setup */
+  function ttyrec_chunk(buf) {
+    var ts = new Date();
+    var chunk = new Buffer(buf.length + 12);
+    /* TTYREC headers */
+    chunk.writeUInt32LE(Math.floor(ts.getTime() / 1000), 0);
+    chunk.writeUInt32LE(1000 * (ts.getTime() % 1000), 4);
+    chunk.writeUInt32LE(buf.length, 8);
+    buf.copy(chunk, 12);
+    ss.data.push(chunk);
+    ss.record.write(chunk);
+  }
+  this.child.stdout.on("data", ttyrec_chunk);
+  this.child.stderr.on("data", ttyrec_chunk);
+  this.child.on("exit", function (code, signal) {
+    ss.exitcode = (code != null ? code : 255);
+    ss.alive = false;
+    fs.unlink(ss.lock);
+    /* Wait for all the data to get collected */
+    setTimeout(ss.cleanup, 1000);
+  });
+  this.write = function (data) {
+    if (this.alive)
+      this.child.stdin.write(data);
+    /* Otherwise, throw some kind of exception? */
+  };
+  this.read = function () {
+    if (this.data.length == 0)
+      return null;
+    var pos = 0;
+    var i = 0;
+    for (i = 0; i < this.data.length; i++)
+      pos += this.data[i].length - 12;
+    var nbuf = new Buffer(pos);
+    var tptr;
+    pos = 0;
+    while (this.data.length > 0) {
+      tptr = this.data.shift();
+      tptr.copy(nbuf, pos, 12);
+      pos += tptr.length - 12;
+    }
+    return nbuf;
+  };
+  this.close = function () {
+    if (this.alive)
+      this.child.kill('SIGHUP');
+  };
+  this.cleanup = function () {
+    /* Call this when the child is dead. */
+    if (this.alive)
+      return;
+    //ss.ptmx.destroy();
+    ss.record.end();
+    /* Give the client a chance to read any leftover data. */
+    if (ss.data.length > 0)
+      setTimeout(ss.remove, 8000);
+    else
+      ss.remove();
+  };
+  this.remove = function () {
+    delete sessions[ss.sessid];
+    console.log("Session " + this.sessid + " removed.");
+  };
+}
+
+/* A few utility functions */
+function timestamp() {
+  dd = new Date();
+  sd = dd.toISOString();
+  sd = sd.slice(0, sd.indexOf("."));
+  return sd.replace("T", ".");
+}
+
+function randkey() {
+  rnum = Math.floor(Math.random() * 65536 * 65536);
+  hexstr = rnum.toString(16);
+  while (hexstr.length < 8)
+    hexstr = "0" + hexstr;
+  return hexstr;
+}
+
+/* Returns a list of the cookies in the request, obviously. */
+function getCookies(req) {
+  cookies = [];
+  if ("cookie" in req.headers) {
+    cookstrs = req.headers["cookie"].split("; ");
+    for (var i = 0; i < cookstrs.length; i++) {
+      eqsign = cookstrs[i].indexOf("=");
+      if (eqsign > 0) {
+        name = cookstrs[i].slice(0, eqsign).toLowerCase();
+        val = cookstrs[i].slice(eqsign + 1);
+        cookies[name] = val;
+      }
+      else if (eqsign < 0)
+        cookies[cookstrs[i]] = null;
+    }
+  }
+  return cookies;
+}
+
+function urlDec(encstr) {
+  var decstr = "";
+  var tnum;
+  for (var i = 0; i < encstr.length; i++)
+  {
+    if (encstr.charAt(i) == "+")
+      decstr += " ";
+    else if (encstr.charAt(i) == "%")
+    {
+      tnum = Number("0x" + encstr.slice(i + 1, 2));
+      if (!isNaN(tnum) && tnum >= 0)
+        decstr += String.fromCharCode(tnum);
+      i += 2;
+    }
+    else
+      decstr += encstr.charAt(i);
+  }
+  return decstr;
+}
+
+/* Returns the contents of a form */
+function getFormValues(formtext) {
+  var pairstrs = formtext.split("&");
+  var data = {};
+  for (var i = 0; i < pairstrs.length; i++)
+  {
+    var eqsign = pairstrs[i].indexOf("=");
+    if (eqsign > 0) {
+      rawname = pairstrs[i].slice(0, eqsign);
+      rawval = pairstrs[i].slice(eqsign + 1);
+      name = urlDec(rawname);
+      val = urlDec(rawval);
+      if (!(name in data))
+        data[name] = [];
+      data[name].push(val);
+    }
+  }
+  return data;
+}
+
+function auth(username, password) {
+  // Real authentication not implemented
+  return true;
+}
+
+function login(req, res, formdata) {
+  if (!("game" in formdata)) {
+    sendError(res, 2, "No game specified.");
+    return;
+  }
+  else if (!("name" in formdata)) {
+    sendError(res, 2, "Username not given.");
+    return;
+  }
+  else if (!("pw" in formdata)) {
+    sendError(res, 2, "Password not given.");
+    return;
+  }
+  var username = formdata["name"][0];
+  var password = formdata["pw"][0];
+  var gname = formdata["game"][0];
+  if (!(gname in games)) {
+    sendError(res, 2, "No such game: " + gname);
+    console.log("Request for nonexistant game \"" + gname + "\"");
+    return;
+  }
+  var progressdir = "/dgldir/inprogress-" + games[gname].uname;
+
+  // This sets up the game once starting is approved.
+  function startgame() {
+    var ts = timestamp();
+    var lockfile = path.join(progressdir, username + ":node:" + ts + ".ttyrec");
+    var ttyrec = path.join("/dgldir/ttyrec", username, gname, ts + ".ttyrec");
+    var nsession = new TermSession(gname, username, [lockfile, ttyrec]);
+    if (nsession) {
+      /* Technically there's a race condition for the "lock"file, but since 
+       * it requires the user deliberately starting two games at similar times, 
+       * it's not too serious. We can't get O_EXCL in Node anyway. */
+      res.writeHead(200, {'Content-Type': 'text/plain'});
+      res.write("l1\n" + nsession.sessid + "\n");
+      res.end();
+      console.log("%s playing %s (key %s, pid %d)", username, gname, 
+                  nsession.sessid, nsession.child.pid);
+    }
+    else {
+      sendError(res, 5, "Failed to open TTY");
+      console.log("Unable to allocate TTY for " + gname);
+    }
+  }
+  function checkit(code, signal) {
+    // check the password
+    if (code != 0) {
+      sendError(res, 3);
+      console.log("Password check failed for user " + username);
+      return;
+    }
+    // check for an existing game
+    fs.readdir(progressdir, function(err, files) {
+      if (!err) {
+        var fre = RegExp("^" + username + ":");
+        for (var i = 0; i < files.length; i++) {
+          if (files[i].match(fre)) {
+            sendError(res, 4, null);
+            return;
+          }
+        }
+      }
+      // If progressdir isn't readable, start a new game anyway.
+      startgame();
+    });
+  }
+  /* Look for the user in the password file */
+  fs.readFile(passwdfile, "utf8", function(err, data) {
+    if (err) {
+      sendError(res, 3);
+      console.log("Can't authenticate: " + err.toString());
+      return;
+    }
+    var dlines = data.split('\n');
+    for (var n = 0; n < dlines.length; n++) {
+      var fields = dlines[n].split(':');
+      if (fields[0] == username) {
+        // check the password with the quickrypt utility
+        checker = require('child_process').spawn("/bin/quickrypt")
+        checker.on("exit", checkit);
+        checker.stdin.end(password + '\n' + fields[2] + '\n', "utf8");
+        return;
+      }
+    }
+    sendError(res, 3);
+    console.log("Attempted login by nonexistent user " + username);
+  });
+  return;
+}
+
+function logout(term, res) {
+  if (!term.alive) {
+    sendError(res, 1, null);
+    return;
+  }
+  cterm.close();
+  var resheaders = {'Content-Type': 'text/plain'};
+  res.writeHead(200, resheaders);
+  res.write("q1\n\n");
+  res.end();
+  return;
+}
+
+function findTermSession(formdata) {
+  if ("id" in formdata) {
+    var sessid = formdata["id"][0];
+    if (sessid in sessions) {
+      return sessions[sessid];
+    }
+  }
+  return null;
+}
+
+function serveStatic(req, res, fname) {
+  var nname = path.normalize(fname);
+  if (nname == "" || nname == "/")
+    nname = "index.html";
+  if (nname.match(/\/$/))
+    path.join(nname, "index.html"); /* it was a directory */
+  var realname = path.join(serveStaticRoot, nname);
+  var extension = path.extname(realname);
+  path.exists(realname, function (exists) {
+    var resheaders = {};
+    if (!exists || !extension || extension == ".html")
+      resheaders["Content-Type"] = "text/html";
+    else if (extension == ".png")
+      resheaders["Content-Type"] = "image/png";
+    else if (extension == ".css")
+      resheaders["Content-Type"] = "text/css";
+    else if (extension == ".js")
+      resheaders["Content-Type"] = "text/javascript";
+    else if (extension == ".svg")
+      resheaders["Content-Type"] = "image/svg+xml";
+    else
+      resheaders["Content-Type"] = "application/octet-stream";
+    if (exists) {
+      fs.readFile(realname, function (error, data) {
+        if (error) {
+          res.writeHead(500, {});
+          res.end();
+        }
+        else {
+          res.writeHead(200, resheaders);
+          res.write(data);
+          res.end();
+        }
+      });
+    }
+    else {
+      res.writeHead(404, resheaders);
+      res.write("<html><head><title>" + nname + "</title></head>\n<body><h1>" + nname + " Not Found</h1></body></html>\n");
+      res.end();
+    }
+  });
+  return;
+}
+
+function readFeed(res, term) {
+  if (term) {
+    var result = term.read();
+    res.writeHead(200, { "Content-Type": "text/plain" });
+    if (result == null)
+      resultstr = "";
+    else
+      resultstr = result.toString("hex");
+    if (result == null && !term.alive) {
+      /* Child has terminated and data is flushed. */
+      res.write("q1\n\n");
+    }
+    else
+      res.write("d" + resultstr.length.toString() + "\n" + resultstr + "\n");
+    res.end();
+  }
+  else {
+    //console.log("Where's the term?");
+    sendError(res, 1, null);
+  }
+}
+
+var errorcodes = [ "Generic Error", "Not logged in", "Invalid data", 
+        "Login failed", "Already playing", "Game launch failed" ];
+
+function sendError(res, ecode, msg) {
+  res.writeHead(200, { "Content-Type": "text/plain" });
+  if (ecode < errorcodes.length && ecode > 0) {
+    var emsg = errorcodes[ecode];
+    if (msg)
+      emsg += ": " + msg;
+    res.write("E" + ecode + '\n' + emsg + '\n');
+  }
+  else
+    res.write("E0\nGeneric Error\n");
+  res.end();
+}
+
+function handler(req, res) {
+  /* default headers for the response */
+  var resheaders = {'Content-Type': 'text/html'};
+  /* The request body will be added to this as it arrives. */
+  var reqbody = "";
+  var formdata;
+
+  /* Register a listener to get the body. */
+  function moredata(chunk) {
+    reqbody += chunk;
+  }
+  req.on('data', moredata);
+
+  /* This will send the response once the whole request is here. */
+  function respond() {
+    formdata = getFormValues(reqbody);
+    var target = url.parse(req.url).pathname;
+    var cterm = findTermSession(formdata);
+    /* First figure out if the client is POSTing to a command interface. */
+    if (req.method == 'POST') {
+      if (target == '/feed') {
+        if (!cterm) {
+          sendError(res, 1, null);
+          return;
+        }
+        if ("quit" in formdata) {
+          /* The client wants to terminate the process. */
+          logout(cterm, res);
+        }
+        else if (formdata["keys"]) {
+          /* process the keys */
+          hexstr = formdata["keys"][0].replace(/[^0-9a-f]/gi, "");
+          if (hexstr.length % 2 != 0) {
+            sendError(res, 2, "incomplete byte");
+            return;
+          }
+          keybuf = new Buffer(hexstr, "hex");
+          cterm.write(keybuf);
+        }
+        readFeed(res, cterm);
+      }
+      else if (target == "/login") {
+        login(req, res, formdata);
+      }
+      else {
+        res.writeHead(405, resheaders);
+        res.end();
+      }
+    }
+    else if (req.method == 'GET' || req.method == 'HEAD') {
+      if (target == '/feed') {
+        if (!cterm) {
+          sendError(res, 1, null);
+          return;
+        }
+        readFeed(res, cterm);
+      }
+      /* Default page, create a new term */
+      /* FIXME New term not created anymore, is a special case still needed? */
+      else if (target == '/') {
+        serveStatic(req, res, "/");
+      }
+      else /* Go look for it in the filesystem */
+        serveStatic(req, res, target);
+    }
+    else { /* Some other method */
+      res.writeHead(501, resheaders);
+      res.write("<html><head><title>501</title></head>\n<body><h1>501 Not Implemented</h1></body></html>\n");
+      res.end();
+    }
+    return;
+  }
+  req.on('end', respond);
+
+}
+
+process.on("exit", function () {
+  for (var sessid in sessions) {
+    if (sessions[sessid].alive)
+      sessions[sessid].child.kill('SIGHUP');
+  }
+  console.log("Quitting...");
+  return;
+});
+
+/* Initialization STARTS HERE */
+process.env["TERM"] = "xterm-256color";
+
+if (process.getuid() != 0) {
+  console.log("Not running as root, cannot chroot.");
+  process.exit(1);
+}
+try {
+  process.chdir(chrootDir); 
+}
+catch (err) {
+  console.log("Cannot enter " + chrootDir + " : " + err);
+  process.exit(1);
+}
+try {
+  daemon.chroot(chrootDir);
+}
+catch (err) {
+  console.log("chroot to " + chrootDir + " failed: " + err);
+  process.exit(1);
+}
+try {
+  // drop gid first, that requires UID=0
+  process.setgid(dropToGID);
+  process.setuid(dropToUID);
+}
+catch (err) {
+  console.log("Could not drop permissions: " + err);
+  process.exit(1);
+}
+
+http.createServer(handler).listen(8080, "127.0.0.1");
+console.log('webttyd running at http://127.0.0.1:8080/');