[usb_gadget p09] Software updates over HTTP.

tools/usb_gadget/server.py

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """WSGI application to manage a USB gadget.
 """
 
+import datetime
+import hashlib
 import re
+import subprocess
 import sys
+import time
+import urllib2
 
 from tornado import httpserver
+from tornado import ioloop
 from tornado import web
 
 import default_gadget
 
 VERSION_PATTERN = re.compile(r'.*usb_gadget-([a-z0-9]{32})\.zip')
 
 address = None
 chip = None
 claimed_by = None
 default = default_gadget.DefaultGadget()
 gadget = None
+hardware = None
+interface = None
+port = None
 
 
 def SwitchGadget(new_gadget):
   if chip.IsConfigured():
     chip.Destroy()
 
   global gadget
   gadget = new_gadget
   gadget.AddStringDescriptor(3, address)
   chip.Create(gadget)
 
 
 class VersionHandler(web.RequestHandler):
 
   def get(self):
     version = 'unpackaged'
     for path in sys.path:
       match = VERSION_PATTERN.match(path)
       if match:
         version = match.group(1)
         break
 
     self.write(version)
 
 
+class UpdateHandler(web.RequestHandler):
+
+  def post(self):
+    fileinfo = self.request.files['file'][0]
+
+    match = VERSION_PATTERN.match(fileinfo['filename'])
+    if match is None:
+      self.write('Filename must contain MD5 hash.')
+      self.set_status(400)
+      return
+
+    content = fileinfo['body']
+    md5sum = hashlib.md5(content).hexdigest()
+    if md5sum != match.group(1):
+      self.write('File hash does not match.')
+      self.set_status(400)
+      return
+
+    filename = 'usb_gadget-{}.zip'.format(md5sum)
+    with open(filename, 'wb') as f:
+      f.write(content)
+
+    args = ['/usr/bin/python', filename,
+            '--interface', interface,
+            '--port', str(port),
+            '--hardware', hardware]
+    if claimed_by is not None:
+      args.extend(['--start-claimed', claimed_by])
+
+    print 'Reloading with version {}...'.format(md5sum)
+
+    global http_server
+    if chip.IsConfigured():
+      chip.Destroy()
+    http_server.stop()
+
+    child = subprocess.Popen(args, close_fds=True)
+
+    while True:
+      child.poll()
+      if child.returncode is not None:
+        self.write('New package exited with error {}.'
+                   .format(child.returncode))
+        self.set_status(500)
+
+        http_server = httpserver.HTTPServer(app)
+        http_server.listen(port)
+        SwitchGadget(gadget)
+        return
+
+      try:
+        f = urllib2.urlopen('http://{}/version'.format(address))
+        if f.getcode() == 200:
+          # Update complete, wait 1 second to make sure buffers are flushed.
+          io_loop = ioloop.IOLoop.instance()
+          io_loop.add_timeout(datetime.timedelta(seconds=1), io_loop.stop)
+          return
+      except urllib2.URLError:
+        pass
+      time.sleep(0.1)
+
+
 class ClaimHandler(web.RequestHandler):
 
   def post(self):
     global claimed_by
 
     if claimed_by is None:
       claimed_by = self.get_argument('session_id')
     else:
       self.write('Device is already claimed by "{}".'.format(claimed_by))
       self.set_status(403)
@@ skipping 23 matching lines @@
 
 class ReconnectHandler(web.RequestHandler):
 
   def post(self):
     if not chip.IsConfigured():
       chip.Create(gadget)
 
 
 app = web.Application([
     (r'/version', VersionHandler),
+    (r'/update', UpdateHandler),
     (r'/claim', ClaimHandler),
     (r'/unclaim', UnclaimHandler),
     (r'/unconfigure', UnconfigureHandler),
     (r'/disconnect', DisconnectHandler),
     (r'/reconnect', ReconnectHandler),
 ])
 
 http_server = httpserver.HTTPServer(app)