bitbake: process/cooker/command: Fix currentAsyncCommand locking/races

currentAsyncCommand currently doesn't have any locking and we have
a conflict in "idle" conditions since the idle functions count needs
to be zero *and* there needs to be no active command.

Move the changes/checks of currentAsyncCommand to within the lock
and then we can add it to the condition for idle, simplifying some
of the code.

(Bitbake rev: b5215887d2f8ea3f28f1ebda721bd5b8f93ec7f3)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/command.py

@@ -51,13 +51,14 @@ class Command:
     """
     A queue of asynchronous commands for bitbake
     """
-    def __init__(self, cooker):
+    def __init__(self, cooker, process_server):
         self.cooker = cooker
         self.cmds_sync = CommandsSync()
         self.cmds_async = CommandsAsync()
         self.remotedatastores = None
 
-        # FIXME Add lock for this
+        self.process_server = process_server
+        # Access with locking using process_server.{get/set/clear}_async_cmd()
         self.currentAsyncCommand = None
 
     def runCommand(self, commandline, process_server, ro_only=False):
@@ -99,18 +100,14 @@ class Command:
                 return None, traceback.format_exc()
             else:
                 return result, None
-        if self.currentAsyncCommand is not None:
-            # Wait for the idle loop to have cleared (30s max)
-            process_server.wait_for_idle(timeout=30)
-            if self.currentAsyncCommand is not None:
-                return None, "Busy (%s in progress)" % self.currentAsyncCommand[0]
         if command not in CommandsAsync.__dict__:
             return None, "No such command"
-        self.currentAsyncCommand = (command, commandline)
-        self.cooker.idleCallBackRegister(self.runAsyncCommand, None)
+        if not process_server.set_async_cmd((command, commandline)):
+            return None, "Busy (%s in progress)" % self.process_server.get_async_cmd()[0]
+        self.cooker.idleCallBackRegister(self.runAsyncCommand, process_server)
         return True, None
 
-    def runAsyncCommand(self, _, _2, halt):
+    def runAsyncCommand(self, _, process_server, halt):
         try:
             self.cooker.process_inotify_updates_apply()
             if self.cooker.state in (bb.cooker.state.error, bb.cooker.state.shutdown, bb.cooker.state.forceshutdown):
@@ -118,8 +115,9 @@ class Command:
                 # and then raise BBHandledException triggering an exit
                 self.cooker.updateCache()
                 return bb.server.process.idleFinish("Cooker in error state")
-            if self.currentAsyncCommand is not None:
-                (command, options) = self.currentAsyncCommand
+            cmd = process_server.get_async_cmd()
+            if cmd is not None:
+                (command, options) = cmd
                 commandmethod = getattr(CommandsAsync, command)
                 needcache = getattr( commandmethod, "needcache" )
                 if needcache and self.cooker.state != bb.cooker.state.running:
@@ -153,7 +151,7 @@ class Command:
         else:
             bb.event.fire(CommandCompleted(), self.cooker.data)
         self.cooker.finishcommand()
-        self.currentAsyncCommand = None
+        self.process_server.clear_async_cmd()
 
     def reset(self):
         if self.remotedatastores:
@@ -746,7 +744,7 @@ class CommandsAsync:
         """
         event = params[0]
         bb.event.fire(eval(event), command.cooker.data)
-        command.currentAsyncCommand = None
+        process_server.clear_async_cmd()
     triggerEvent.needcache = False
 
     def resetCooker(self, command, params):

bitbake/lib/bb/cooker.py

@@ -149,7 +149,7 @@ class BBCooker:
     Manages one bitbake build run
     """
 
-    def __init__(self, featureSet=None, idleCallBackRegister=None, waitIdle=None):
+    def __init__(self, featureSet=None, server=None):
         self.recipecaches = None
         self.eventlog = None
         self.skiplist = {}
@@ -163,8 +163,12 @@ class BBCooker:
 
         self.configuration = bb.cookerdata.CookerConfiguration()
 
-        self.idleCallBackRegister = idleCallBackRegister
-        self.waitIdle = waitIdle
+        self.process_server = server
+        self.idleCallBackRegister = None
+        self.waitIdle = None
+        if server:
+            self.idleCallBackRegister = server.register_idle_function
+            self.waitIdle = server.wait_for_idle
 
         bb.debug(1, "BBCooker starting %s" % time.time())
         sys.stdout.flush()
@@ -203,7 +207,7 @@ class BBCooker:
         except UnsupportedOperation:
             pass
 
-        self.command = bb.command.Command(self)
+        self.command = bb.command.Command(self, self.process_server)
         self.state = state.initial
 
         self.parser = None

bitbake/lib/bb/server/process.py

@@ -154,10 +154,30 @@ class ProcessServer():
 
         return ret
 
+    def _idle_check(self):
+        return len(self._idlefuns) == 0 and self.cooker.command.currentAsyncCommand is None
+
     def wait_for_idle(self, timeout=30):
         # Wait for the idle loop to have cleared
-        with self.idle_cond:
-            self.idle_cond.wait_for(lambda: len(self._idlefuns) == 0, timeout)
+        with bb.utils.lock_timeout(self._idlefuncsLock):
+            return self.idle_cond.wait_for(self._idle_check, timeout) is not False
+
+    def set_async_cmd(self, cmd):
+        with bb.utils.lock_timeout(self._idlefuncsLock):
+            ret = self.idle_cond.wait_for(self._idle_check, 30)
+            if ret is False:
+                return False
+            self.cooker.command.currentAsyncCommand = cmd
+            return True
+
+    def clear_async_cmd(self):
+        with bb.utils.lock_timeout(self._idlefuncsLock):
+            self.cooker.command.currentAsyncCommand = None
+            self.idle_cond.notify_all()
+
+    def get_async_cmd(self):
+        with bb.utils.lock_timeout(self._idlefuncsLock):
+            return self.cooker.command.currentAsyncCommand
 
     def main(self):
         self.cooker.pre_serve()
@@ -183,11 +203,9 @@ class ProcessServer():
                 self.controllersock = False
             if self.haveui:
                 # Wait for the idle loop to have cleared (30s max)
-                self.wait_for_idle(30)
-                if self.cooker.command.currentAsyncCommand is not None:
+                if not self.wait_for_idle(30):
                     serverlog("Idle loop didn't finish queued commands after 30s, exiting.")
                     self.quit = True
-
                 fds.remove(self.command_channel)
                 bb.event.unregister_UIHhandler(self.event_handle, True)
                 self.command_channel_reply.writer.close()
@@ -624,7 +642,7 @@ def execServer(lockfd, readypipeinfd, lockname, sockname, server_timeout, xmlrpc
         writer = ConnectionWriter(readypipeinfd)
         try:
             featureset = []
-            cooker = bb.cooker.BBCooker(featureset, server.register_idle_function, server.wait_for_idle)
+            cooker = bb.cooker.BBCooker(featureset, server)
             cooker.configuration.profile = profile
         except bb.BBHandledException:
             return None