X-Git-Url: http://xvm.mit.edu/gitweb/invirt/packages/invirt-web.git/blobdiff_plain/08d9836a894fad232049e2adc59c131bc6dc1aaf..b6054ddecbc4d4a9b8e822ff8f0ace386e5e6e00:/templates/main.py?ds=inline

diff --git a/templates/main.py b/templates/main.py
index ec1eca5..6ec853d 100755
--- a/templates/main.py
+++ b/templates/main.py
@@ -1,26 +1,47 @@
 #!/usr/bin/python
+"""Main CGI script for web interface"""
 
-import sys
+import base64
+import cPickle
 import cgi
+import datetime
+import getafsgroups
+import hmac
 import os
+import random
+import re
+import sha
+import simplejson
 import string
 import subprocess
-import re
+import sys
 import time
-import cPickle
-import base64
-import sha
-import hmac
-import datetime
-import StringIO
-import getafsgroups
+from StringIO import StringIO
+
+
+def revertStandardError():
+    """Move stderr to stdout, and return the contents of the old stderr."""
+    errio = sys.stderr
+    if not isinstance(errio, StringIO):
+        return None
+    sys.stderr = sys.stdout
+    errio.seek(0)
+    return errio.read()
+
+def printError():
+    """Revert stderr to stdout, and print the contents of stderr"""
+    if isinstance(sys.stderr, StringIO):
+        print revertStandardError()
+
+if __name__ == '__main__':
+    import atexit
+    atexit.register(printError)
+    sys.stderr = StringIO()
 
-sys.stderr = StringIO.StringIO()
 sys.path.append('/home/ecprice/.local/lib/python2.5/site-packages')
 
 from Cheetah.Template import Template
 from sipb_xen_database import *
-import random
 
 class MyException(Exception):
     """Base class for my exceptions"""
@@ -42,7 +63,14 @@ class CodeError(MyException):
     """Exception for internal errors or bad faith input."""
     pass
 
+def helppopup(subj):
+    """Return HTML code for a (?) link to a specified help topic"""
+    return ('<span class="helplink"><a href="help?subject=' + subj + 
+            '&amp;simple=true" target="_blank" ' + 
+            'onclick="return helppopup(\'' + subj + '\')">(?)</a></span>')
+
 class Global(object):
+    """Global state of the system, to avoid duplicate remctls to get state"""
     def __init__(self, user):
         self.user = user
 
@@ -52,16 +80,66 @@ class Global(object):
         return self._uptimes
     uptimes = property(__get_uptimes)
 
-g = None
-
-def helppopup(subj):
-    """Return HTML code for a (?) link to a specified help topic"""
-    return '<span class="helplink"><a href="help?subject='+subj+'&amp;simple=true" target="_blank" onclick="return helppopup(\''+subj+'\')">(?)</a></span>'
-
+    def clear(self):
+        """Clear the state so future accesses reload it."""
+        for attr in ('_uptimes', ):
+            if hasattr(self, attr):
+                delattr(self, attr)
 
-global_dict = {}
-global_dict['helppopup'] = helppopup
+g = None
 
+class User:
+    """User class (sort of useless, I admit)"""
+    def __init__(self, username, email):
+        self.username = username
+        self.email = email
+
+def makeErrorPre(old, addition):
+    if addition is None:
+        return
+    if old:
+        return old[:-6]  + '\n----\n' + str(addition) + '</pre>'
+    else:
+        return '<p>STDERR:</p><pre>' + str(addition) + '</pre>'
+
+Template.helppopup = staticmethod(helppopup)
+Template.err = None
+
+class JsonDict:
+    """Class to store a dictionary that will be converted to JSON"""
+    def __init__(self, **kws):
+        self.data = kws
+        if 'err' in kws:
+            err = kws['err']
+            del kws['err']
+            self.addError(err)
+
+    def __str__(self):
+        return simplejson.dumps(self.data)
+
+    def addError(self, text):
+        """Add stderr text to be displayed on the website."""
+        self.data['err'] = \
+            makeErrorPre(self.data.get('err'), text)
+
+class Defaults:
+    """Class to store default values for fields."""
+    memory = 256
+    disk = 4.0
+    cdrom = ''
+    name = ''
+    vmtype = 'hvm'
+    def __init__(self, max_memory=None, max_disk=None, **kws):
+        if max_memory is not None:
+            self.memory = min(self.memory, max_memory)
+        if max_disk is not None:
+            self.max_disk = min(self.disk, max_disk)
+        for key in kws:
+            setattr(self, key, kws[key])
+
+
+
+default_headers = {'Content-Type': 'text/html'}
 
 # ... and stolen from xend/uuid.py
 def randomUUID():
@@ -83,8 +161,16 @@ MIN_DISK_SINGLE = 0.1
 MAX_VMS_TOTAL = 10
 MAX_VMS_ACTIVE = 4
 
-def getMachinesByOwner(owner):
-    """Return the machines owned by a given owner."""
+def getMachinesByOwner(user, machine=None):
+    """Return the machines owned by the same as a machine.
+    
+    If the machine is None, return the machines owned by the same
+    user.
+    """
+    if machine:
+        owner = machine.owner
+    else:
+        owner = user.username
     return Machine.select_by(owner=owner)
 
 def maxMemory(user, machine=None, on=True):
@@ -99,25 +185,42 @@ def maxMemory(user, machine=None, on=True):
     """
     if not on:
         return MAX_MEMORY_SINGLE
-    machines = getMachinesByOwner(user.username)
+    machines = getMachinesByOwner(user, machine)
     active_machines = [x for x in machines if g.uptimes[x]]
     mem_usage = sum([x.memory for x in active_machines if x != machine])
     return min(MAX_MEMORY_SINGLE, MAX_MEMORY_TOTAL-mem_usage)
 
 def maxDisk(user, machine=None):
-    machines = getMachinesByOwner(user.username)
+    machines = getMachinesByOwner(user, machine)
     disk_usage = sum([sum([y.size for y in x.disks])
                       for x in machines if x != machine])
     return min(MAX_DISK_SINGLE, MAX_DISK_TOTAL-disk_usage/1024.)
 
-def canAddVm(user):
-    machines = getMachinesByOwner(user.username)
+def cantAddVm(user):
+    machines = getMachinesByOwner(user)
     active_machines = [x for x in machines if g.uptimes[x]]
-    return (len(machines) < MAX_VMS_TOTAL and
-            len(active_machines) < MAX_VMS_ACTIVE)
+    if len(machines) >= MAX_VMS_TOTAL:
+        return 'You have too many VMs to create a new one.'
+    if len(active_machines) >= MAX_VMS_ACTIVE:
+        return ('You already have the maximum number of VMs turned on.  '
+                'To create more, turn one off.')
+    return False
 
 def haveAccess(user, machine):
-    """Return whether a user has access to a machine"""
+    """Return whether a user has adminstrative access to a machine"""
+    if user.username == 'moo':
+        return True
+    if user.username in (machine.administrator, machine.owner):
+        return True
+    if getafsgroups.checkAfsGroup(user.username, machine.administrator, 
+                                  'athena.mit.edu'): #XXX Cell?
+        return True
+    if getafsgroups.checkLockerOwner(user.username, machine.owner):
+        return True
+    return owns(user, machine)
+
+def owns(user, machine):
+    """Return whether a user owns a machine"""
     if user.username == 'moo':
         return True
     return getafsgroups.checkLockerOwner(user.username, machine.owner)
@@ -126,14 +229,14 @@ def error(op, user, fields, err, emsg):
     """Print an error page when a CodeError occurs"""
     d = dict(op=op, user=user, errorMessage=str(err),
              stderr=emsg)
-    return Template(file='error.tmpl', searchList=[d, global_dict]);
+    return Template(file='error.tmpl', searchList=[d]);
 
 def invalidInput(op, user, fields, err, emsg):
     """Print an error page when an InvalidInput exception occurs"""
     d = dict(op=op, user=user, err_field=err.err_field,
              err_value=str(err.err_value), stderr=emsg,
              errorMessage=str(err))
-    return Template(file='invalid.tmpl', searchList=[d, global_dict]);
+    return Template(file='invalid.tmpl', searchList=[d]);
 
 def validMachineName(name):
     """Check that name is valid for a machine name"""
@@ -172,11 +275,11 @@ def remctl(*args, **kws):
                          + list(args),
                          stdout=subprocess.PIPE,
                          stderr=subprocess.PIPE)
+    v = p.wait()
     if kws.get('err'):
-        p.wait()
         return p.stdout.read(), p.stderr.read()
-    if p.wait():
-        print >> sys.stderr, 'Error on remctl', args, ':'
+    if v:
+        print >> sys.stderr, 'Error', v, 'on remctl', args, ':'
         print >> sys.stderr, p.stderr.read()
         raise CodeError('ERROR on remctl')
     return p.stdout.read()
@@ -198,10 +301,10 @@ def bootMachine(machine, cdtype):
     id of the CD (e.g. 'gutsy_i386')
     """
     if cdtype is not None:
-        remctl('web', 'vmboot', machine.name,
+        remctl('control', machine.name, 'create', 
                cdtype)
     else:
-        remctl('web', 'vmboot', machine.name)
+        remctl('control', machine.name, 'create')
 
 def registerMachine(machine):
     """Register a machine to be controlled by the web interface"""
@@ -255,13 +358,16 @@ def statusInfo(machine):
 
     Gets and parses xm list --long
     """
-    value_string, err_string = remctl('list-long', machine.name, err=True)
+    value_string, err_string = remctl('control', machine.name, 'list-long', 
+                                      err=True)
     if 'Unknown command' in err_string:
-        raise CodeError("ERROR in remctl list-long %s is not registered" % (machine.name,))
+        raise CodeError("ERROR in remctl list-long %s is not registered" % 
+                        (machine.name,))
     elif 'does not exist' in err_string:
         return None
     elif err_string:
-        raise CodeError("ERROR in remctl list-long %s:  %s" % (machine.name, err_string))
+        raise CodeError("ERROR in remctl list-long %s:  %s" % 
+                        (machine.name, err_string))
     status = parseStatus(value_string)
     return status
 
@@ -286,9 +392,11 @@ def createVm(user, name, memory, disk, is_hvm, cdrom):
         if disk > maxDisk(user) * 1024:
             raise InvalidInput('disk', disk,
                                "Max %s" % maxDisk(user))
-        if not canAddVm(user):
-            raise InvalidInput('create', True, 'Unable to create more VMs')
-        res = meta.engine.execute('select nextval(\'"machines_machine_id_seq"\')')
+        reason = cantAddVm(user)
+        if reason:
+            raise InvalidInput('create', True, reason)
+        res = meta.engine.execute('select nextval('
+                                  '\'"machines_machine_id_seq"\')')
         id = res.fetchone()[0]
         machine = Machine()
         machine.machine_id = id
@@ -304,10 +412,11 @@ def createVm(user, name, memory, disk, is_hvm, cdrom):
         ctx.current.save(machine)
         disk = Disk(machine.machine_id, 
                     'hda', disk)
-        open = NIC.select_by(machine_id=None)
-        if not open: #No IPs left!
-            raise CodeError("No IP addresses left!  Contact sipb-xen-dev@mit.edu")
-        nic = open[0]
+        open_nics = NIC.select_by(machine_id=None)
+        if not open_nics: #No IPs left!
+            raise CodeError("No IP addresses left!  "
+                            "Contact sipb-xen-dev@mit.edu")
+        nic = open_nics[0]
         nic.machine_id = machine.machine_id
         nic.hostname = name
         ctx.current.save(nic)    
@@ -356,16 +465,15 @@ def validDisk(user, disk, machine=None):
                            "Minimum %s GB" % MIN_DISK_SINGLE)
     return disk
 
-def create(user, fields):
-    """Handler for create requests."""
+def parseCreate(user, fields):
     name = fields.getfirst('name')
     if not validMachineName(name):
-        raise InvalidInput('name', name)
+        raise InvalidInput('name', name, 'You must provide a machine name.')
     name = name.lower()
 
     if Machine.get_by(name=name):
         raise InvalidInput('name', name,
-                           "Already exists")
+                           "Name already exists.")
     
     memory = fields.getfirst('memory')
     memory = validMemory(user, memory, on=True)
@@ -380,21 +488,45 @@ def create(user, fields):
 
     cdrom = fields.getfirst('cdrom')
     if cdrom is not None and not CDROM.get(cdrom):
-        raise CodeError("Invalid cdrom type '%s'" % cdrom)    
-    
-    machine = createVm(user, name, memory, disk, is_hvm, cdrom)
-    d = dict(user=user,
-             machine=machine)
-    return Template(file='create.tmpl',
-                   searchList=[d, global_dict]);
+        raise CodeError("Invalid cdrom type '%s'" % cdrom)
+    return dict(user=user, name=name, memory=memory, disk=disk,
+                is_hvm=is_hvm, cdrom=cdrom)
 
-def listVms(user, fields):
-    """Handler for list requests."""
+def create(user, fields):
+    """Handler for create requests."""
+    js = fields.getfirst('js')
+    try:
+        parsed_fields = parseCreate(user, fields)
+        machine = createVm(**parsed_fields)
+    except InvalidInput, err:
+        if not js:
+            raise
+    else:
+        err = None
+        if not js:
+            d = dict(user=user,
+                     machine=machine)
+            return Template(file='create.tmpl', searchList=[d])
+    g.clear() #Changed global state
+    d = getListDict(user)
+    d['err'] = err
+    if err:
+        for field in fields.keys():
+            setattr(d['defaults'], field, fields.getfirst(field))
+    else:
+        d['new_machine'] = parsed_fields['name']
+    t = Template(file='list.tmpl', searchList=[d])
+    return JsonDict(createtable=t.createTable(),
+                    machinelist=t.machineList(d['machines']))
+
+
+def getListDict(user):
     machines = [m for m in Machine.select() if haveAccess(user, m)]    
     on = {}
     has_vnc = {}
     on = g.uptimes
     for m in machines:
+        m.uptime = g.uptimes.get(m)
         if not on[m]:
             has_vnc[m] = 'Off'
         elif m.type.hvm:
@@ -405,20 +537,38 @@ def listVms(user, fields):
     #         status = statusInfo(m)
     #         on[m.name] = status is not None
     #         has_vnc[m.name] = hasVnc(status)
-    max_mem=maxMemory(user)
-    max_disk=maxDisk(user)
+    max_memory = maxMemory(user)
+    max_disk = maxDisk(user)
+    defaults = Defaults(max_memory=max_memory,
+                        max_disk=max_disk,
+                        cdrom='gutsy-i386')
     d = dict(user=user,
-             can_add_vm=canAddVm(user),
-             max_mem=max_mem,
+             cant_add_vm=cantAddVm(user),
+             max_memory=max_memory,
              max_disk=max_disk,
-             default_mem=max_mem,
-             default_disk=min(4.0, max_disk),
+             defaults=defaults,
              machines=machines,
              has_vnc=has_vnc,
              uptimes=g.uptimes,
              cdroms=CDROM.select())
-    return Template(file='list.tmpl', searchList=[d, global_dict])
+    return d
 
+def listVms(user, fields):
+    """Handler for list requests."""
+    d = getListDict(user)
+    t = Template(file='list.tmpl', searchList=[d])
+    js = fields.getfirst('js')
+    if not js:
+        return t
+    if js == 'machinelist':
+        return t.machineList(d['machines'])
+    elif js.startswith('machinerow-'):
+        request_machine_id = int(js.split('-')[1])
+        m = [x for x in d['machines'] if x.id == request_machine_id]
+        return t.machineRow(m)
+    elif js == 'createtable':
+        return t.createTable()
+            
 def testMachineId(user, machineId, exists=True):
     """Parse, validate and check authorization for a given machineId.
 
@@ -447,9 +597,12 @@ def vnc(user, fields):
 
     You might want iptables like:
 
-    -t nat -A PREROUTING -s ! 18.181.0.60 -i eth1 -p tcp -m tcp --dport 10003 -j DNAT --to-destination 18.181.0.60:10003 
-    -t nat -A POSTROUTING -d 18.181.0.60 -o eth1 -p tcp -m tcp --dport 10003 -j SNAT --to-source 18.187.7.142 
-    -A FORWARD -d 18.181.0.60 -i eth1 -o eth1 -p tcp -m tcp --dport 10003 -j ACCEPT
+    -t nat -A PREROUTING -s ! 18.181.0.60 -i eth1 -p tcp -m tcp \
+      --dport 10003 -j DNAT --to-destination 18.181.0.60:10003 
+    -t nat -A POSTROUTING -d 18.181.0.60 -o eth1 -p tcp -m tcp \
+      --dport 10003 -j SNAT --to-source 18.187.7.142 
+    -A FORWARD -d 18.181.0.60 -i eth1 -o eth1 -p tcp -m tcp \
+      --dport 10003 -j ACCEPT
 
     Remember to enable iptables!
     echo 1 > /proc/sys/net/ipv4/ip_forward
@@ -460,12 +613,12 @@ def vnc(user, fields):
 
     data = {}
     data["user"] = user.username
-    data["machine"]=machine.name
-    data["expires"]=time.time()+(5*60)
-    pickledData = cPickle.dumps(data)
+    data["machine"] = machine.name
+    data["expires"] = time.time()+(5*60)
+    pickled_data = cPickle.dumps(data)
     m = hmac.new(TOKEN_KEY, digestmod=sha)
-    m.update(pickledData)
-    token = {'data': pickledData, 'digest': m.digest()}
+    m.update(pickled_data)
+    token = {'data': pickled_data, 'digest': m.digest()}
     token = cPickle.dumps(token)
     token = base64.urlsafe_b64encode(token)
     
@@ -478,8 +631,7 @@ def vnc(user, fields):
              machine=machine,
              hostname=os.environ.get('SERVER_NAME', 'localhost'),
              authtoken=token)
-    return Template(file='vnc.tmpl',
-                   searchList=[d, global_dict])
+    return Template(file='vnc.tmpl', searchList=[d])
 
 def getNicInfo(data_dict, machine):
     """Helper function for info, get data on nics for a machine.
@@ -495,7 +647,8 @@ def getNicInfo(data_dict, machine):
     nic_fields = []
     for i in range(len(machine.nics)):
         nic_fields.extend([(x % i, y % i) for x, y in nic_fields_template])
-        data_dict['nic%s_hostname' % i] = machine.nics[i].hostname + '.servers.csail.mit.edu'
+        data_dict['nic%s_hostname' % i] = (machine.nics[i].hostname + 
+                                           '.servers.csail.mit.edu')
         data_dict['nic%s_mac' % i] = machine.nics[i].mac_addr
         data_dict['nic%s_ip' % i] = machine.nics[i].ip
     if len(machine.nics) == 1:
@@ -513,15 +666,17 @@ def getDiskInfo(data_dict, machine):
     disk_fields = []
     for disk in machine.disks:
         name = disk.guest_device_name
-        disk_fields.extend([(x % name, y % name) for x, y in disk_fields_template])
+        disk_fields.extend([(x % name, y % name) for x, y in 
+                            disk_fields_template])
         data_dict['%s_size' % name] = "%0.1f GB" % (disk.size / 1024.)
     return disk_fields
 
 def deleteVM(machine):
     """Delete a VM."""
-    remctl('destroy', machine.name, err=True)
+    remctl('control', machine.name, 'destroy', err=True)
     transaction = ctx.current.create_transaction()
-    delete_disk_pairs = [(machine.name, d.guest_device_name) for d in machine.disks]
+    delete_disk_pairs = [(machine.name, d.guest_device_name) 
+                         for d in machine.disks]
     try:
         for nic in machine.nics:
             nic.machine_id = None
@@ -538,8 +693,7 @@ def deleteVM(machine):
         remctl('web', 'lvremove', mname, dname)
     unregisterMachine(machine)
 
-def command(user, fields):
-    """Handler for running commands like boot and delete on a VM."""
+def commandResult(user, fields):
     print >> sys.stderr, time.time()-start_time
     machine = testMachineId(user, fields.getfirst('machine_id'))
     action = fields.getfirst('action')
@@ -547,22 +701,51 @@ def command(user, fields):
     print >> sys.stderr, time.time()-start_time
     if cdrom is not None and not CDROM.get(cdrom):
         raise CodeError("Invalid cdrom type '%s'" % cdrom)    
-    if action not in ('Reboot', 'Power on', 'Power off', 'Shutdown', 'Delete VM'):
+    if action not in ('Reboot', 'Power on', 'Power off', 'Shutdown', 
+                      'Delete VM'):
         raise CodeError("Invalid action '%s'" % action)
     if action == 'Reboot':
         if cdrom is not None:
-            remctl('reboot', machine.name, cdrom)
+            out, err = remctl('control', machine.name, 'reboot', cdrom,
+                              err=True)
         else:
-            remctl('reboot', machine.name)
+            out, err = remctl('control', machine.name, 'reboot',
+                              err=True)
+        if err:
+            if re.match("Error: Domain '.*' does not exist.", err):
+                raise InvalidInput("action", "reboot", 
+                                   "Machine is not on")
+            else:
+                print >> sys.stderr, 'Error on reboot:'
+                print >> sys.stderr, err
+                raise CodeError('ERROR on remctl')
+                
     elif action == 'Power on':
         if maxMemory(user) < machine.memory:
             raise InvalidInput('action', 'Power on',
-                               "You don't have enough free RAM quota to turn on this machine")
+                               "You don't have enough free RAM quota "
+                               "to turn on this machine.")
         bootMachine(machine, cdrom)
     elif action == 'Power off':
-        remctl('destroy', machine.name)
+        out, err = remctl('control', machine.name, 'destroy', err=True)
+        if err:
+            if re.match("Error: Domain '.*' does not exist.", err):
+                raise InvalidInput("action", "Power off", 
+                                   "Machine is not on.")
+            else:
+                print >> sys.stderr, 'Error on power off:'
+                print >> sys.stderr, err
+                raise CodeError('ERROR on remctl')
     elif action == 'Shutdown':
-        remctl('shutdown', machine.name)
+        out, err = remctl('control', machine.name, 'shutdown', err=True)
+        if err:
+            if re.match("Error: Domain '.*' does not exist.", err):
+                raise InvalidInput("action", "Shutdown", 
+                                   "Machine is not on.")
+            else:
+                print >> sys.stderr, 'Error on Shutdown:'
+                print >> sys.stderr, err
+                raise CodeError('ERROR on remctl')
     elif action == 'Delete VM':
         deleteVM(machine)
     print >> sys.stderr, time.time()-start_time
@@ -570,32 +753,79 @@ def command(user, fields):
     d = dict(user=user,
              command=action,
              machine=machine)
-    return Template(file="command.tmpl", searchList=[d, global_dict])
+    return d
 
-def testOwner(user, owner, machine=None):
-    if owner == machine.owner:   #XXX What do we do when you lose access to the locker?
-        return owner
+def command(user, fields):
+    """Handler for running commands like boot and delete on a VM."""
+    js = fields.getfirst('js')
+    try:
+        d = commandResult(user, fields)
+    except InvalidInput, err:
+        if not js:
+            raise
+        result = None
+    else:
+        err = None
+        result = 'Success!'
+        if not js:
+            return Template(file='command.tmpl', searchList=[d])
+    if js == 'list':
+        g.clear() #Changed global state
+        d = getListDict(user)
+        t = Template(file='list.tmpl', searchList=[d])
+        return JsonDict(createtable=t.createTable(),
+                        machinelist=t.machineList(d['machines']),
+                        result=result,
+                        err=err)
+    elif js == 'info':
+        machine = testMachineId(user, fields.getfirst('machine_id'))
+        d = infoDict(user, machine)
+        t = Template(file='info.tmpl', searchList=[d])
+        return JsonDict(info=t.infoTable(),
+                        commands=t.commands(),
+                        modify=t.modifyForm(),
+                        result=result,
+                        err=err)
+    else:
+        raise InvalidInput('js', js, 'Not a known js type.')
+
+def testAdmin(user, admin, machine):
+    if admin in (None, machine.administrator):
+        return None
+    if admin == user.username:
+        return admin
+    if getafsgroups.checkAfsGroup(user.username, admin, 'athena.mit.edu'):
+        return admin
+    if getafsgroups.checkAfsGroup(user.username, 'system:'+admin,
+                                  'athena.mit.edu'):
+        return 'system:'+admin
+    raise InvalidInput('administrator', admin, 
+                       'You must control the group you move it to.')
+    
+def testOwner(user, owner, machine):
+    if owner in (None, machine.owner):
+        return None
     value = getafsgroups.checkLockerOwner(user.username, owner, verbose=True)
     if value == True:
         return owner
     raise InvalidInput('owner', owner, value)
 
 def testContact(user, contact, machine=None):
+    if contact in (None, machine.contact):
+        return None
     if not re.match("^[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,4}$", contact, re.I):
-        raise InvalidInput('contact', contact, "Not a valid email")
+        raise InvalidInput('contact', contact, "Not a valid email.")
     return contact
 
 def testDisk(user, disksize, machine=None):
     return disksize
 
 def testName(user, name, machine=None):
-    if name is None:
+    if name in (None, machine.name):
         return None
     if not Machine.select_by(name=name):
         return name
-    if name == machine.name:
-        return name
-    raise InvalidInput('name', name, "Already taken")
+    raise InvalidInput('name', name, "Name is already taken.")
 
 def testHostname(user, hostname, machine):
     for nic in machine.nics:
@@ -606,23 +836,22 @@ def testHostname(user, hostname, machine):
         raise InvalidInput('hostname', hostname,
                            "Already exists")
     if not re.match("^[A-Z0-9-]{1,22}$", hostname, re.I):
-        raise InvalidInput('hostname', hostname, "Not a valid hostname; must only use number, letters, and dashes.")
+        raise InvalidInput('hostname', hostname, "Not a valid hostname; "
+                           "must only use number, letters, and dashes.")
     return hostname
 
-def modify(user, fields):
-    """Handler for modifying attributes of a machine."""
-
+def modifyDict(user, fields):
     olddisk = {}
     transaction = ctx.current.create_transaction()
     try:
         machine = testMachineId(user, fields.getfirst('machine_id'))
         owner = testOwner(user, fields.getfirst('owner'), machine)
-        contact = testContact(user, fields.getfirst('contact'))
-        hostname = testHostname(owner, fields.getfirst('hostname'),
-                                machine)
+        admin = testAdmin(user, fields.getfirst('administrator'), machine)
+        contact = testContact(user, fields.getfirst('contact'), machine)
+        hostname = testHostname(owner, fields.getfirst('hostname'), machine)
         name = testName(user, fields.getfirst('name'), machine)
         oldname = machine.name
-        command="modify"
+        command = "modify"
 
         memory = fields.getfirst('memory')
         if memory is not None:
@@ -638,15 +867,20 @@ def modify(user, fields):
                 disk.size = disksize
                 ctx.current.save(disk)
         
-        # XXX first NIC gets hostname on change?  Interface doesn't support more.
+        # XXX first NIC gets hostname on change?  
+        # Interface doesn't support more.
         for nic in machine.nics[:1]:
             nic.hostname = hostname
             ctx.current.save(nic)
 
-        if owner is not None and owner != machine.owner:
+        if owner is not None:
             machine.owner = owner
-        if name is not None and name != machine.name:
+        if name is not None:
             machine.name = name
+        if admin is not None:
+            machine.administrator = admin
+        if contact is not None:
+            machine.contact = contact
             
         ctx.current.save(machine)
         transaction.commit()
@@ -655,55 +889,98 @@ def modify(user, fields):
         raise
     for diskname in olddisk:
         remctl("web", "lvresize", oldname, diskname, str(olddisk[diskname]))
-    if name is not None and name != oldname:
+    if name is not None:
         for disk in machine.disks:
-            if oldname != name:
-                remctl("web", "lvrename", oldname, disk.guest_device_name, name)
+            remctl("web", "lvrename", oldname, disk.guest_device_name, name)
         remctl("web", "moveregister", oldname, name)
-    d = dict(user=user,
-             command=command,
-             machine=machine)
-    return Template(file="command.tmpl", searchList=[d, global_dict])    
-
+    return dict(user=user,
+                command=command,
+                machine=machine)
+    
+def modify(user, fields):
+    """Handler for modifying attributes of a machine."""
+    js = fields.getfirst('js')
+    try:
+        modify_dict = modifyDict(user, fields)
+    except InvalidInput, err:
+        if not js:
+            raise
+        result = ''
+        machine = testMachineId(user, fields.getfirst('machine_id'))
+    else:
+        machine = modify_dict['machine']
+        result='Success!'
+        err = None
+        if not js:
+            return Template(file='command.tmpl', searchList=[modify_dict])
+    info_dict = infoDict(user, machine)
+    info_dict['err'] = err
+    if err:
+        for field in fields.keys():
+            setattr(info_dict['defaults'], field, fields.getfirst(field))
+    t = Template(file='info.tmpl', searchList=[info_dict])
+    return JsonDict(info=t.infoTable(),
+                    commands=t.commands(),
+                    modify=t.modifyForm(),
+                    result=result,
+                    err=err)
+    
 
-def help(user, fields):
+def helpHandler(user, fields):
     """Handler for help messages."""
     simple = fields.getfirst('simple')
     subjects = fields.getlist('subject')
     
-    mapping = dict(paravm_console="""
+    help_mapping = dict(paravm_console="""
 ParaVM machines do not support console access over VNC.  To access
 these machines, you either need to boot with a liveCD and ssh in or
 hope that the sipb-xen maintainers add support for serial consoles.""",
-                   hvm_paravm="""
+                        hvm_paravm="""
 HVM machines use the virtualization features of the processor, while
 ParaVM machines use Xen's emulation of virtualization features.  You
 want an HVM virtualized machine.""",
-                   cpu_weight="""Don't ask us!  We're as mystified as you are.""",
-                   owner="""The Owner must be the name of a locker that you are an AFS
-administrator of.  In particular, you or an AFS group you are a member
-of must have AFS rlidwka bits on the locker.  You can check see who
-administers the LOCKER locker using the command 'fs la /mit/LOCKER' on
-Athena.)""")
+                        cpu_weight="""
+Don't ask us!  We're as mystified as you are.""",
+                        owner="""
+The owner field is used to determine <a
+href="help?subject=quotas">quotas</a>.  It must be the name of a
+locker that you are an AFS administrator of.  In particular, you or an
+AFS group you are a member of must have AFS rlidwka bits on the
+locker.  You can check see who administers the LOCKER locker using the
+command 'fs la /mit/LOCKER' on Athena.)  See also <a
+href="help?subject=administrator">administrator</a>.""",
+                        administrator="""
+The administrator field determines who can access the console and
+power on and off the machine.  This can be either a user or a moira
+group.""",
+                        quotas="""
+Quotas are determined on a per-locker basis.  Each quota may have a
+maximum of 512 megabytes of active ram, 50 gigabytes of disk, and 4
+active machines."""
+                   )
     
+    if not subjects:
+        subjects = sorted(help_mapping.keys())
+        
     d = dict(user=user,
              simple=simple,
              subjects=subjects,
-             mapping=mapping)
+             mapping=help_mapping)
     
-    return Template(file="help.tmpl", searchList=[d, global_dict])
+    return Template(file="help.tmpl", searchList=[d])
     
 
-def info(user, fields):
-    """Handler for info on a single VM."""
-    machine = testMachineId(user, fields.getfirst('machine_id'))
+def badOperation(u, e):
+    raise CodeError("Unknown operation")
+
+def infoDict(user, machine):
     status = statusInfo(machine)
     has_vnc = hasVnc(status)
     if status is None:
         main_status = dict(name=machine.name,
                            memory=str(machine.memory))
-        uptime=None
-        cputime=None
+        uptime = None
+        cputime = None
     else:
         main_status = dict(status[1:])
         start_time = float(main_status.get('start_time', 0))
@@ -714,6 +991,7 @@ def info(user, fields):
      on_poweroff on_crash on_xend_start on_xend_stop bootloader""".split()
     display_fields = [('name', 'Name'),
                       ('owner', 'Owner'),
+                      ('administrator', 'Administrator'),
                       ('contact', 'Contact'),
                       ('type', 'Type'),
                       'NIC_INFO',
@@ -735,15 +1013,18 @@ def info(user, fields):
     machine_info['name'] = machine.name
     machine_info['type'] = machine.type.hvm and 'HVM' or 'ParaVM'
     machine_info['owner'] = machine.owner
+    machine_info['administrator'] = machine.administrator
     machine_info['contact'] = machine.contact
 
     nic_fields = getNicInfo(machine_info, machine)
     nic_point = display_fields.index('NIC_INFO')
-    display_fields = display_fields[:nic_point] + nic_fields + display_fields[nic_point+1:]
+    display_fields = (display_fields[:nic_point] + nic_fields + 
+                      display_fields[nic_point+1:])
 
     disk_fields = getDiskInfo(machine_info, machine)
     disk_point = display_fields.index('DISK_INFO')
-    display_fields = display_fields[:disk_point] + disk_fields + display_fields[disk_point+1:]
+    display_fields = (display_fields[:disk_point] + disk_fields + 
+                      display_fields[disk_point+1:])
     
     main_status['memory'] += ' MB'
     for field, disp in display_fields:
@@ -758,10 +1039,17 @@ def info(user, fields):
             #fields.append((disp, None))
     max_mem = maxMemory(user, machine)
     max_disk = maxDisk(user, machine)
+    defaults=Defaults()
+    for name in 'machine_id name administrator owner memory contact'.split():
+        setattr(defaults, name, getattr(machine, name))
+    if machine.nics:
+        defaults.hostname = machine.nics[0].hostname
+    defaults.disk = "%0.2f" % (machine.disks[0].size/1024.)
     d = dict(user=user,
              cdroms=CDROM.select(),
              on=status is not None,
              machine=machine,
+             defaults=defaults,
              has_vnc=has_vnc,
              uptime=str(uptime),
              ram=machine.memory,
@@ -769,8 +1057,13 @@ def info(user, fields):
              max_disk=max_disk,
              owner_help=helppopup("owner"),
              fields = fields)
-    return Template(file='info.tmpl',
-                   searchList=[d, global_dict])
+    return d
+
+def info(user, fields):
+    """Handler for info on a single VM."""
+    machine = testMachineId(user, fields.getfirst('machine_id'))
+    d = infoDict(user, machine)
+    return Template(file='info.tmpl', searchList=[d])
 
 mapping = dict(list=listVms,
                vnc=vnc,
@@ -778,24 +1071,27 @@ mapping = dict(list=listVms,
                modify=modify,
                info=info,
                create=create,
-               help=help)
+               help=helpHandler)
+
+def printHeaders(headers):
+    for key, value in headers.iteritems():
+        print '%s: %s' % (key, value)
+    print
+
+
+def getUser():
+    """Return the current user based on the SSL environment variables"""
+    if 'SSL_CLIENT_S_DN_Email' in os.environ:
+        username = os.environ['SSL_CLIENT_S_DN_Email'].split("@")[0]
+        return User(username, os.environ['SSL_CLIENT_S_DN_Email'])
+    else:
+        return User('moo', 'nobody')
 
 if __name__ == '__main__':
     start_time = time.time()
     fields = cgi.FieldStorage()
-    class User:
-        username = "moo"
-        email = 'moo@cow.com'
-    u = User()
+    u = getUser()
     g = Global(u)
-    if 'SSL_CLIENT_S_DN_Email' in os.environ:
-        username = os.environ[ 'SSL_CLIENT_S_DN_Email'].split("@")[0]
-        u.username = username
-        u.email = os.environ[ 'SSL_CLIENT_S_DN_Email']
-    else:
-        u.username = 'moo'
-        u.email = 'nobody'
-    connect('postgres://sipb-xen@sipb-xen-dev/sipb_xen')
     operation = os.environ.get('PATH_INFO', '')
     if not operation:
         print "Status: 301 Moved Permanently"
@@ -807,39 +1103,42 @@ if __name__ == '__main__':
     if not operation:
         operation = 'list'
 
-    def badOperation(u, e):
-        raise CodeError("Unknown operation")
+
 
     fun = mapping.get(operation, badOperation)
-    if fun not in (help, ):
-        connect('postgres://sipb-xen@sipb-xen-dev/sipb_xen')
+
+    if fun not in (helpHandler, ):
+        connect('postgres://sipb-xen@sipb-xen-dev.mit.edu/sipb_xen')
     try:
         output = fun(u, fields)
-        print 'Content-Type: text/html\n'
-        sys.stderr.seek(0)
-        e = sys.stderr.read()
-        sys.stderr=sys.stdout
+
+        headers = dict(default_headers)
+        if isinstance(output, tuple):
+            new_headers, output = output
+            headers.update(new_headers)
+
+        e = revertStandardError()
         if e:
-            output = str(output)
-            output = output.replace('<body>', '<body><p>STDERR:</p><pre>'+e+'</pre>')
+            output.addError(e)
+        printHeaders(headers)
         print output
-    except CodeError, err:
-        print 'Content-Type: text/html\n'
-        sys.stderr.seek(0)
-        e = sys.stderr.read()
-        sys.stderr=sys.stdout
-        print error(operation, u, fields, err, e)
-    except InvalidInput, err:
-        print 'Content-Type: text/html\n'
-        sys.stderr.seek(0)
-        e = sys.stderr.read()
-        sys.stderr=sys.stdout
-        print invalidInput(operation, u, fields, err, e)
-    except:
+    except Exception, err:
+        if not fields.has_key('js'):
+            if isinstance(err, CodeError):
+                print 'Content-Type: text/html\n'
+                e = revertStandardError()
+                print error(operation, u, fields, err, e)
+                sys.exit(1)
+            if isinstance(err, InvalidInput):
+                print 'Content-Type: text/html\n'
+                e = revertStandardError()
+                print invalidInput(operation, u, fields, err, e)
+                sys.exit(1)
         print 'Content-Type: text/plain\n'
-        sys.stderr.seek(0)
-        e = sys.stderr.read()
+        print 'Uh-oh!  We experienced an error.'
+        print 'Please email sipb-xen@mit.edu with the contents of this page.'
+        print '----'
+        e = revertStandardError()
         print e
         print '----'
-        sys.stderr = sys.stdout
         raise