X-Git-Url: http://xvm.mit.edu/gitweb/invirt/packages/invirt-web.git/blobdiff_plain/b1f4849b34267d7c937600e777b79d9455266df1..7f1e55f398d25ec110573104910c04cfede8e722:/templates/main.py

diff --git a/templates/main.py b/templates/main.py
index f64fe3d..0bf16b9 100755
--- a/templates/main.py
+++ b/templates/main.py
@@ -1,266 +1,111 @@
 #!/usr/bin/python
+"""Main CGI script for web interface"""
 
-import sys
+import base64
+import cPickle
 import cgi
+import datetime
+import hmac
 import os
-import string
-import subprocess
-import re
-import time
-import cPickle
-import base64
 import sha
-import hmac
-import datetime
-import StringIO
-import getafsgroups
-
-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"""
-    pass
+import simplejson
+import sys
+import time
+from StringIO import StringIO
 
-class InvalidInput(MyException):
-    """Exception for user-provided input is invalid but maybe in good faith.
 
-    This would include setting memory to negative (which might be a
-    typo) but not setting an invalid boot CD (which requires bypassing
-    the select box).
-    """
-    def __init__(self, err_field, err_value, expl=None):
-        MyException.__init__(self, expl)
-        self.err_field = err_field
-        self.err_value = err_value
+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()
 
-class CodeError(MyException):
-    """Exception for internal errors or bad faith input."""
-    pass
+def printError():
+    """Revert stderr to stdout, and print the contents of stderr"""
+    if isinstance(sys.stderr, StringIO):
+        print revertStandardError()
 
-class Global(object):
-    def __init__(self, user):
-        self.user = user
+if __name__ == '__main__':
+    import atexit
+    atexit.register(printError)
+    sys.stderr = StringIO()
 
-    def __get_uptimes(self):
-        if not hasattr(self, '_uptimes'):
-            self._uptimes = getUptimes(Machine.select())
-        return self._uptimes
-    uptimes = property(__get_uptimes)
+sys.path.append('/home/ecprice/.local/lib/python2.5/site-packages')
 
-g = None
+from Cheetah.Template import Template
+from sipb_xen_database import Machine, CDROM, ctx, connect
+import validation
+from webcommon import InvalidInput, CodeError, g
+import controls
 
 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>'
-
-
-global_dict = {}
-global_dict['helppopup'] = helppopup
-
-
-# ... and stolen from xend/uuid.py
-def randomUUID():
-    """Generate a random UUID."""
-
-    return [ random.randint(0, 255) for _ in range(0, 16) ]
-
-def uuidToString(u):
-    """Turn a numeric UUID to a hyphen-seperated one."""
-    return "-".join(["%02x" * 4, "%02x" * 2, "%02x" * 2, "%02x" * 2,
-                     "%02x" * 6]) % tuple(u)
-
-MAX_MEMORY_TOTAL = 512
-MAX_MEMORY_SINGLE = 256
-MIN_MEMORY_SINGLE = 16
-MAX_DISK_TOTAL = 50
-MAX_DISK_SINGLE = 50
-MIN_DISK_SINGLE = 0.1
-MAX_VMS_TOTAL = 10
-MAX_VMS_ACTIVE = 4
-
-def getMachinesByOwner(owner):
-    """Return the machines owned by a given owner."""
-    return Machine.select_by(owner=owner)
-
-def maxMemory(user, machine=None):
-    """Return the maximum memory for a machine or a user.
-
-    If machine is None, return the memory available for a new 
-    machine.  Else, return the maximum that machine can have.
-
-    on is a dictionary from machines to booleans, whether a machine is
-    on.  If None, it is recomputed. XXX make this global?
-    """
-
-    machines = getMachinesByOwner(user.username)
-    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)
-    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)
-    active_machines = [x for x in machines if g.uptimes[x]]
-    return (len(machines) < MAX_VMS_TOTAL and
-            len(active_machines) < MAX_VMS_ACTIVE)
-
-def haveAccess(user, machine):
-    """Return whether a user has access to a machine"""
-    if user.username == 'moo':
-        return True
-    return getafsgroups.checkLockerOwner(user.username,machine.owner)
+    return ('<span class="helplink"><a href="help?subject=' + subj + 
+            '&amp;simple=true" target="_blank" ' + 
+            'onclick="return helppopup(\'' + subj + '\')">(?)</a></span>')
+
+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'}
 
 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]);
-
-def validMachineName(name):
-    """Check that name is valid for a machine name"""
-    if not name:
-        return False
-    charset = string.ascii_letters + string.digits + '-_'
-    if name[0] in '-_' or len(name) > 22:
-        return False
-    for x in name:
-        if x not in charset:
-            return False
-    return True
-
-def kinit(username = 'tabbott/extra', keytab = '/etc/tabbott.keytab'):
-    """Kinit with a given username and keytab"""
-
-    p = subprocess.Popen(['kinit', "-k", "-t", keytab, username],
-                         stderr=subprocess.PIPE)
-    e = p.wait()
-    if e:
-        raise CodeError("Error %s in kinit: %s" % (e, p.stderr.read()))
-
-def checkKinit():
-    """If we lack tickets, kinit."""
-    p = subprocess.Popen(['klist', '-s'])
-    if p.wait():
-        kinit()
-
-def remctl(*args, **kws):
-    """Perform a remctl and return the output.
-
-    kinits if necessary, and outputs errors to stderr.
-    """
-    checkKinit()
-    p = subprocess.Popen(['remctl', 'black-mesa.mit.edu']
-                         + list(args),
-                         stdout=subprocess.PIPE,
-                         stderr=subprocess.PIPE)
-    if kws.get('err'):
-        p.wait()
-        return p.stdout.read(), p.stderr.read()
-    if p.wait():
-        raise CodeError('ERROR on remctl %s: %s' %
-                          (args, p.stderr.read()))
-    return p.stdout.read()
-
-def lvcreate(machine, disk):
-    """Create a single disk for a machine"""
-    remctl('web', 'lvcreate', machine.name,
-           disk.guest_device_name, str(disk.size))
-    
-def makeDisks(machine):
-    """Update the lvm partitions to add a disk."""
-    for disk in machine.disks:
-        lvcreate(machine, disk)
-
-def bootMachine(machine, cdtype):
-    """Boot a machine with a given boot CD.
-
-    If cdtype is None, give no boot cd.  Otherwise, it is the string
-    id of the CD (e.g. 'gutsy_i386')
-    """
-    if cdtype is not None:
-        remctl('web', 'vmboot', machine.name,
-               cdtype)
-    else:
-        remctl('web', 'vmboot', machine.name)
-
-def registerMachine(machine):
-    """Register a machine to be controlled by the web interface"""
-    remctl('web', 'register', machine.name)
-
-def unregisterMachine(machine):
-    """Unregister a machine to not be controlled by the web interface"""
-    remctl('web', 'unregister', machine.name)
-
-def parseStatus(s):
-    """Parse a status string into nested tuples of strings.
-
-    s = output of xm list --long <machine_name>
-    """
-    values = re.split('([()])', s)
-    stack = [[]]
-    for v in values[2:-2]: #remove initial and final '()'
-        if not v:
-            continue
-        v = v.strip()
-        if v == '(':
-            stack.append([])
-        elif v == ')':
-            if len(stack[-1]) == 1:
-                stack[-1].append('')
-            stack[-2].append(stack[-1])
-            stack.pop()
-        else:
-            if not v:
-                continue
-            stack[-1].extend(v.split())
-    return stack[-1]
-
-def getUptimes(machines=None):
-    """Return a dictionary mapping machine names to uptime strings"""
-    value_string = remctl('web', 'listvms')
-    lines = value_string.splitlines()
-    d = {}
-    for line in lines:
-        lst = line.split()
-        name, id = lst[:2]
-        uptime = ' '.join(lst[2:])
-        d[name] = uptime
-    ans = {}
-    for m in machines:
-        ans[m] = d.get(m.name)
-    return ans
-
-def statusInfo(machine):
-    """Return the status list for a given machine.
-
-    Gets and parses xm list --long
-    """
-    value_string, err_string = remctl('list-long', machine.name, err=True)
-    if 'Unknown command' in err_string:
-        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))
-    status = parseStatus(value_string)
-    return status
+    return Template(file='invalid.tmpl', searchList=[d])
 
 def hasVnc(status):
     """Does the machine with a given status list support VNC?"""
@@ -272,98 +117,23 @@ def hasVnc(status):
             return 'location' in d
     return False
 
-def createVm(user, name, memory, disk, is_hvm, cdrom):
-    """Create a VM and put it in the database"""
-    # put stuff in the table
-    transaction = ctx.current.create_transaction()
-    try:
-        if memory > maxMemory(user):
-            raise InvalidInput('memory', memory,
-                               "Max %s" % maxMemory(user))
-        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"\')')
-        id = res.fetchone()[0]
-        machine = Machine()
-        machine.machine_id = id
-        machine.name = name
-        machine.memory = memory
-        machine.owner = user.username
-        machine.contact = user.email
-        machine.uuid = uuidToString(randomUUID())
-        machine.boot_off_cd = True
-        machine_type = Type.get_by(hvm=is_hvm)
-        machine.type_id = machine_type.type_id
-        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]
-        nic.machine_id = machine.machine_id
-        nic.hostname = name
-        ctx.current.save(nic)    
-        ctx.current.save(disk)
-        transaction.commit()
-    except:
-        transaction.rollback()
-        raise
-    registerMachine(machine)
-    makeDisks(machine)
-    # tell it to boot with cdrom
-    bootMachine(machine, cdrom)
-
-    return machine
-
-def validMemory(user, memory, machine=None):
-    """Parse and validate limits for memory for a given user and machine."""
-    try:
-        memory = int(memory)
-        if memory < MIN_MEMORY_SINGLE:
-            raise ValueError
-    except ValueError:
-        raise InvalidInput('memory', memory, 
-                           "Minimum %s MB" % MIN_MEMORY_SINGLE)
-    if memory > maxMemory(user, machine):
-        raise InvalidInput('memory', memory,
-                           'Maximum %s MB' % maxMemory(user, machine))
-    return memory
-
-def validDisk(user, disk, machine=None):
-    """Parse and validate limits for disk for a given user and machine."""
-    try:
-        disk = float(disk)
-        if disk > maxDisk(user, machine):
-            raise InvalidInput('disk', disk,
-                               "Maximum %s G" % maxDisk(user, machine))
-        disk = int(disk * 1024)
-        if disk < MIN_DISK_SINGLE * 1024:
-            raise ValueError
-    except ValueError:
-        raise InvalidInput('disk', disk,
-                           "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)
+    if not validation.validMachineName(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.")
     
+    owner = validation.testOwner(user, fields.getfirst('owner'))
+
     memory = fields.getfirst('memory')
-    memory = validMemory(user, memory)
+    memory = validation.validMemory(user, memory, on=True)
     
     disk = fields.getfirst('disk')
-    disk = validDisk(user, disk)
+    disk = validation.validDisk(user, disk)
 
     vm_type = fields.getfirst('vmtype')
     if vm_type not in ('hvm', 'paravm'):
@@ -372,63 +142,66 @@ 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(contact=user, name=name, memory=memory, disk=disk,
+                owner=owner, is_hvm=is_hvm, cdrom=cdrom)
 
-def listVms(user, fields):
-    """Handler for list requests."""
-    machines = [m for m in Machine.select() if haveAccess(user, m)]    
+def create(user, fields):
+    """Handler for create requests."""
+    try:
+        parsed_fields = parseCreate(user, fields)
+        machine = controls.createVm(**parsed_fields)
+    except InvalidInput, err:
+        pass
+    else:
+        err = None
+    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']
+    return Template(file='list.tmpl', searchList=[d])
+
+
+def getListDict(user):
+    machines = [m for m in Machine.select() 
+                if validation.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:
             has_vnc[m] = True
         else:
             has_vnc[m] = "ParaVM"+helppopup("paravm_console")
-    #     for m in machines:
-    #         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 = validation.maxMemory(user)
+    max_disk = validation.maxDisk(user)
+    defaults = Defaults(max_memory=max_memory,
+                        max_disk=max_disk,
+                        owner=user,
+                        cdrom='gutsy-i386')
     d = dict(user=user,
-             can_add_vm=canAddVm(user),
-             max_mem=max_mem,
+             cant_add_vm=validation.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])
-
-def testMachineId(user, machineId, exists=True):
-    """Parse, validate and check authorization for a given machineId.
-
-    If exists is False, don't check that it exists.
-    """
-    if machineId is None:
-        raise CodeError("No machine ID specified")
-    try:
-        machineId = int(machineId)
-    except ValueError:
-        raise CodeError("Invalid machine ID '%s'" % machineId)
-    machine = Machine.get(machineId)
-    if exists and machine is None:
-        raise CodeError("No such machine ID '%s'" % machineId)
-    if machine is not None and not haveAccess(user, machine):
-        raise CodeError("No access to machine ID '%s'" % machineId)
-    return machine
+    return d
 
+def listVms(user, fields):
+    """Handler for list requests."""
+    d = getListDict(user)
+    return Template(file='list.tmpl', searchList=[d])
+            
 def vnc(user, fields):
     """VNC applet page.
 
@@ -439,29 +212,32 @@ 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
     """
-    machine = testMachineId(user, fields.getfirst('machine_id'))
+    machine = validation.testMachineId(user, fields.getfirst('machine_id'))
     
     TOKEN_KEY = "0M6W0U1IXexThi5idy8mnkqPKEq1LtEnlK/pZSn0cDrN"
 
     data = {}
-    data["user"] = user.username
-    data["machine"]=machine.name
-    data["expires"]=time.time()+(5*60)
-    pickledData = cPickle.dumps(data)
+    data["user"] = user
+    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)
     
-    status = statusInfo(machine)
+    status = controls.statusInfo(machine)
     has_vnc = hasVnc(status)
     
     d = dict(user=user,
@@ -470,8 +246,7 @@ 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.
@@ -480,14 +255,16 @@ def getNicInfo(data_dict, machine):
     of (key, name) pairs to display "name: data_dict[key]" to the user.
     """
     data_dict['num_nics'] = len(machine.nics)
-    nic_fields_template = [('nic%s_hostname', 'NIC %s hostname'),
+    nic_fields_template = [('nic%s_hostname', 'NIC %s Hostname'),
                            ('nic%s_mac', 'NIC %s MAC Addr'),
                            ('nic%s_ip', 'NIC %s IP'),
                            ]
     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'
+        if not i:
+            data_dict['nic%s_hostname' % i] = (machine.name + 
+                                               '.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:
@@ -505,199 +282,165 @@ 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])
-        data_dict['%s_size' % name] = "%0.1f GB" % (disk.size / 1024.)
+        disk_fields.extend([(x % name, y % name) for x, y in 
+                            disk_fields_template])
+        data_dict['%s_size' % name] = "%0.1f GiB" % (disk.size / 1024.)
     return disk_fields
 
-def deleteVM(machine):
-    """Delete a VM."""
-    remctl('destroy', machine.name, err=True)
-    transaction = ctx.current.create_transaction()
-    delete_disk_pairs = [(machine.name, d.guest_device_name) for d in machine.disks]
-    try:
-        for nic in machine.nics:
-            nic.machine_id = None
-            nic.hostname = None
-            ctx.current.save(nic)
-        for disk in machine.disks:
-            ctx.current.delete(disk)
-        ctx.current.delete(machine)
-        transaction.commit()
-    except:
-        transaction.rollback()
-        raise
-    for mname, dname in delete_disk_pairs:
-        remctl('web', 'lvremove', mname, dname)
-    unregisterMachine(machine)
-
 def command(user, fields):
     """Handler for running commands like boot and delete on a VM."""
-    print >> sys.stderr, time.time()-start_time
-    machine = testMachineId(user, fields.getfirst('machine_id'))
-    action = fields.getfirst('action')
-    cdrom = fields.getfirst('cdrom')
-    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'):
-        raise CodeError("Invalid action '%s'" % action)
-    if action == 'Reboot':
-        if cdrom is not None:
-            remctl('reboot', machine.name, cdrom)
-        else:
-            remctl('reboot', machine.name)
-    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")
-        bootMachine(machine, cdrom)
-    elif action == 'Power off':
-        remctl('destroy', machine.name)
-    elif action == 'Shutdown':
-        remctl('shutdown', machine.name)
-    elif action == 'Delete VM':
-        deleteVM(machine)
-    print >> sys.stderr, time.time()-start_time
-
-    d = dict(user=user,
-             command=action,
-             machine=machine)
-    return Template(file="command.tmpl", searchList=[d, global_dict])
-
-def testOwner(user, owner, machine=None):
-    if not getafsgroups.checkLockerOwner(user.username, owner):
-        raise InvalidInput('owner', owner,
-                           "Invalid")
-    return owner
-
-def testContact(user, contact, machine=None):
-    if contact != user.email:
-        raise InvalidInput('contact', contact,
-                           "Invalid")
-    return contact
-
-def testDisk(user, disksize, machine=None):
-    return disksize
-
-def testName(user, name, machine=None):
-    if Machine.select_by(name=name) == []:
-        return name
-    if name == machine.name:
-        return name
-    raise InvalidInput('name', name,
-                       "Already taken")
-
-def testHostname(user, hostname, machine):
-    for nic in machine.nics:
-        if hostname == nic.hostname:
-            return hostname
-    # check if doesn't already exist
-    if NIC.select_by(hostname=hostname) == []:
-        return hostname
-    raise InvalidInput('hostname', hostname,
-                       "Different from before")
-
-
-def modify(user, fields):
-    """Handler for modifying attributes of a machine."""
-    #XXX not written yet
+    back = fields.getfirst('back')
+    try:
+        d = controls.commandResult(user, fields)
+        if d['command'] == 'Delete VM':
+            back = 'list'
+    except InvalidInput, err:
+        if not back:
+            raise
+        print >> sys.stderr, err
+        result = None
+    else:
+        result = 'Success!'
+        if not back:
+            return Template(file='command.tmpl', searchList=[d])
+    if back == 'list':
+        g.clear() #Changed global state
+        d = getListDict(user)
+        d['result'] = result
+        return Template(file='list.tmpl', searchList=[d])
+    elif back == 'info':
+        machine = validation.testMachineId(user, fields.getfirst('machine_id'))
+        d = infoDict(user, machine)
+        d['result'] = result
+        return Template(file='info.tmpl', searchList=[d])
+    else:
+        raise InvalidInput('back', back, 'Not a known back page.')
 
+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)
-        name = testName(user, fields.getfirst('name'), machine)
+        machine = validation.testMachineId(user, fields.getfirst('machine_id'))
+        owner = validation.testOwner(user, fields.getfirst('owner'), machine)
+        admin = validation.testAdmin(user, fields.getfirst('administrator'),
+                                     machine)
+        contact = validation.testContact(user, fields.getfirst('contact'),
+                                         machine)
+        name = validation.testName(user, fields.getfirst('name'), machine)
         oldname = machine.name
-        command="modify"
-        olddisk = {}
+        command = "modify"
 
         memory = fields.getfirst('memory')
         if memory is not None:
-            memory = validMemory(user, memory, machine)
-        else:
-            memory = machine.memory
-        if memory != machine.memory:
+            memory = validation.validMemory(user, memory, machine, on=False)
             machine.memory = memory
-
-        disksize = testDisk(user, fields.getfirst('disk'))
+ 
+        disksize = validation.testDisk(user, fields.getfirst('disk'))
         if disksize is not None:
-            disksize = validDisk(user, disksize, machine)
-        else:
-            disksize = machine.disks[0].size
-        for disk in machine.disks:
-            olddisk[disk.guest_device_name] = disk.size
-            disk.size = disksize
-            ctx.current.save(disk)
+            disksize = validation.validDisk(user, disksize, machine)
+            disk = machine.disks[0]
+            if disk.size != disksize:
+                olddisk[disk.guest_device_name] = disksize
+                disk.size = disksize
+                ctx.current.save(disk)
         
-        # XXX all NICs get same hostname on change?  Interface doesn't support more.
-        for nic in machine.nics:
-            nic.hostname = hostname
-            ctx.current.save(nic)
-
-        if owner != machine.owner:
+        if owner is not None:
             machine.owner = owner
-        if 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()
     except:
         transaction.rollback()
         raise
-    remctl("web", "moveregister", oldname, name)
-    for disk in machine.disks:
-        # XXX all disks get the same size on change?  Interface doesn't support more.
-        if disk.size != olddisk[disk.guest_device_name]:
-            remctl("web", "lvresize", oldname, disk.guest_device_name, str(disk.size))
-        if oldname != name:
-            remctl("web", "lvrename", oldname, disk.guest_device_name, name)
-    d = dict(user=user,
-             command=command,
-             machine=machine)
-    return Template(file="command.tmpl", searchList=[d, global_dict])    
-
+    for diskname in olddisk:
+        controls.resizeDisk(oldname, diskname, str(olddisk[diskname]))
+    if name is not None:
+        controls.renameMachine(machine, oldname, name)
+    return dict(user=user,
+                command=command,
+                machine=machine)
+    
+def modify(user, fields):
+    """Handler for modifying attributes of a machine."""
+    try:
+        modify_dict = modifyDict(user, fields)
+    except InvalidInput, err:
+        result = None
+        machine = validation.testMachineId(user, fields.getfirst('machine_id'))
+    else:
+        machine = modify_dict['machine']
+        result = 'Success!'
+        err = None
+    info_dict = infoDict(user, machine)
+    info_dict['err'] = err
+    if err:
+        for field in fields.keys():
+            setattr(info_dict['defaults'], field, fields.getfirst(field))
+    info_dict['result'] = result
+    return Template(file='info.tmpl', searchList=[info_dict])
+    
 
-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'))
-    status = statusInfo(machine)
+def badOperation(u, e):
+    raise CodeError("Unknown operation")
+
+def infoDict(user, machine):
+    status = controls.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))
@@ -708,6 +451,7 @@ 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',
@@ -729,17 +473,20 @@ 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'
+    main_status['memory'] += ' MiB'
     for field, disp in display_fields:
         if field in ('uptime', 'cputime') and locals()[field] is not None:
             fields.append((disp, locals()[field]))
@@ -750,12 +497,17 @@ def info(user, fields):
         else:
             pass
             #fields.append((disp, None))
-    max_mem = maxMemory(user, machine)
-    max_disk = maxDisk(user, machine)
+    max_mem = validation.maxMemory(user, machine)
+    max_disk = validation.maxDisk(user, machine)
+    defaults = Defaults()
+    for name in 'machine_id name administrator owner memory contact'.split():
+        setattr(defaults, name, getattr(machine, name))
+    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,
@@ -763,8 +515,13 @@ 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 = validation.testMachineId(user, fields.getfirst('machine_id'))
+    d = infoDict(user, machine)
+    return Template(file='info.tmpl', searchList=[d])
 
 mapping = dict(list=listVms,
                vnc=vnc,
@@ -772,27 +529,67 @@ 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 username
+    else:
+        return 'moo'
+
+def main(operation, user, fields):    
+    fun = mapping.get(operation, badOperation)
+
+    if fun not in (helpHandler, ):
+        connect('postgres://sipb-xen@sipb-xen-dev.mit.edu/sipb_xen')
+    try:
+        output = fun(u, fields)
+
+        headers = dict(DEFAULT_HEADERS)
+        if isinstance(output, tuple):
+            new_headers, output = output
+            headers.update(new_headers)
+
+        e = revertStandardError()
+        if e:
+            output.addError(e)
+        printHeaders(headers)
+        print output
+    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'
+        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 '----'
+        raise
 
 if __name__ == '__main__':
     start_time = time.time()
     fields = cgi.FieldStorage()
-    class User:
-        username = "moo"
-        email = 'moo@cow.com'
-    u = User()
-    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')
+    u = getUser()
+    g.user = u
     operation = os.environ.get('PATH_INFO', '')
-#    print 'Content-Type: text/plain\n'
-#    print operation
     if not operation:
         print "Status: 301 Moved Permanently"
         print 'Location: ' + os.environ['SCRIPT_NAME']+'/\n'
@@ -803,38 +600,5 @@ if __name__ == '__main__':
     if not operation:
         operation = 'list'
 
-    def badOperation(u, e):
-        raise CodeError("Unknown operation")
+    main(operation, u, fields)
 
-    fun = mapping.get(operation, badOperation)
-    if fun not in (help, ):
-        connect('postgres://sipb-xen@sipb-xen-dev/sipb_xen')
-    try:
-        output = fun(u, fields)
-        print 'Content-Type: text/html\n'
-        sys.stderr.seek(0)
-        e = sys.stderr.read()
-        if e:
-            output = str(output)
-            output = output.replace('<body>', '<body><p>STDERR:</p><pre>'+e+'</pre>')
-        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:
-        print 'Content-Type: text/plain\n'
-        sys.stderr.seek(0)
-        e = sys.stderr.read()
-        print e
-        print '----'
-        sys.stderr = sys.stdout
-        raise