add 5 minute timeout on binary patch construction

When making bsdiff/imgdiff patches, give up after 5 minutes.  (On
certain large files it can take hours to build a patch, if it ever
even completes.)

Change-Id: I123c06f8194f85f6f4e640f7eb31c7746f76ba4d

tools/releasetools/common.py

@@ -900,10 +900,26 @@ class Difference(object):
       cmd.append(ttemp.name)
       cmd.append(ptemp.name)
       p = Run(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
-      _, err = p.communicate()
+      err = []
+      def run():
+        _, e = p.communicate()
+        if e: err.append(e)
+      th = threading.Thread(target=run)
+      th.start()
+      th.join(timeout=300)   # 5 mins
+      if th.is_alive():
+        print "WARNING: diff command timed out"
+        p.terminate()
+        th.join(5)
+        if th.is_alive():
+          p.kill()
+          th.join()
+
       if err or p.returncode != 0:
-        print "WARNING: failure running %s:\n%s\n" % (diff_program, err)
+        print "WARNING: failure running %s:\n%s\n" % (
-        return None
+            diff_program, "".join(err))
+        self.patch = None
+        return None, None, None
       diff = ptemp.read()
     finally:
       ptemp.close()

tools/releasetools/ota_from_target_files

@@ -853,15 +853,20 @@ else if get_stage("%(bcb_dev)s", "stage") != "3/3" then
         GetBuildProp("ro.build.thumbprint", OPTIONS.source_info_dict))
 
   if updating_boot:
+    boot_type, boot_device = common.GetTypeAndDevice("/boot", OPTIONS.info_dict)
     d = common.Difference(target_boot, source_boot)
     _, _, d = d.ComputePatch()
+    if d is None:
+      include_full_boot = True
+      common.ZipWriteStr(output_zip, "boot.img", target_boot.data)
+    else:
+      include_full_boot = False
+
       print "boot      target: %d  source: %d  diff: %d" % (
           target_boot.size, source_boot.size, len(d))
 
       common.ZipWriteStr(output_zip, "patch/boot.img.p", d)
 
-    boot_type, boot_device = common.GetTypeAndDevice("/boot", OPTIONS.info_dict)
-
       script.PatchCheck("%s:%s:%d:%s:%d:%s" %
                         (boot_type, boot_device,
                          source_boot.size, source_boot.sha1,
@@ -906,9 +911,15 @@ else
 
   if not OPTIONS.two_step:
     if updating_boot:
+      if include_full_boot:
+        print "boot image changed; including full."
+        script.Print("Installing boot image...")
+        script.WriteRawImage("/boot", "boot.img")
+      else:
         # Produce the boot image by applying a patch to the current
         # contents of the boot partition, and write it back to the
         # partition.
+        print "boot image changed; including patch."
         script.Print("Patching boot image...")
         script.ShowProgress(0.1, 10)
         script.ApplyPatch("%s:%s:%d:%s:%d:%s"
@@ -918,7 +929,6 @@ else
                           "-",
                           target_boot.size, target_boot.sha1,
                           source_boot.sha1, "patch/boot.img.p")
-      print "boot image changed; including."
     else:
       print "boot image unchanged; skipping."