前面讲到BitbakeServer实际上是一个ProcessServer，因此对ProcessServer进行了一个大略的分析集，这里着重再介绍一下ProcessServer.main。
1. 初始化
def main(self):
self.cooker.pre_serve() #调用cooker.pre_serve()，进入服务前的一些动作，这个后面继续分解
bb.utils.set_process_name("Cooker") #设置本进程名称为“Cooker”
ready = [] #声明一个列表，这个列表从后文看列应该是一个套接字描述符列表
self.controllersock = False #声明本服务为非控制器套接字
fds = [self.sock] #将本服务套接字添加进文件描述符列表fds
if self.xmlrpc:
fds.append(self.xmlrpc) #若支持xmlrpc，那么将xmlrpc同样放入文件描述符列表
print("Entering server connection loop") #即将进入服务器连接循环
def disconnect_client(self, fds): #定义一个断开客户连接的函数，后面会要用到
if not self.haveui:
return
print("Disconnecting Client")
fds.remove(self.controllersock) #从文件描述符列表中删除控制器套接字描述符
fds.remove(self.command_channel) #从文件描述符列表中删除命令通道套接字描述符，从这两处并列的删除步骤看，服务器接受两个套接字
bb.event.unregister_UIHhandler(self.event_handle, True) #从事件处理器中删除本事件处理器
self.command_channel_reply.writer.close() #关闭命令通道写端
self.event_writer.writer.close() #关闭事件写端
del self.event_writer #析构事件作者
self.controllersock.close() #控制器套接字关闭
self.controllersock = False
self.haveui = False
self.lastui = time.time()
self.cooker.clientComplete() #调用cooker.clientComplete函数，后面再进行分解
if self.timeout is None:
print("No timeout, exiting.")
self.quit = True
2. 服务器连接循环
while not self.quit:
if self.sock in ready: #假设本套接字在ready列表，那么从本套接字接受一个控制器套接字连入，初始本套接字并不在ready列表
self.controllersock, address = self.sock.accept()
if self.haveui:
print("Dropping connection attempt as we have a UI %s" % (str(ready)))
self.controllersock.close()
else:
print("Accepting %s" % (str(ready)))
fds.append(self.controllersock) #将控制器套接字添加到文件描述符列表
if self.controllersock in ready: #若控制器套接字就绪，则从控制器套接字接受新的ui文件描述符
try:
print("Connecting Client")
ui_fds = recvfds(self.controllersock, 3) #根据控制器套接字中取3个套接字，分别用于事件作者，命令通道作者，命令通道读者
# Where to write events to
writer = ConnectionWriter(ui_fds[0]) #新建连接作者，用于事件处理
self.event_handle = bb.event.register_UIHhandler(writer, True) #新建本事件处理器
self.event_writer = writer
# Where to read commands from
reader = ConnectionReader(ui_fds[1]) #新建连接命令通道读者
fds.append(reader) #将读者添加进文件描述符列表
self.command_channel = reader
# Where to send command return values to
writer = ConnectionWriter(ui_fds[2]) #新建连接命令通道作者，用于向客户发出回应
self.command_channel_reply = writer
self.haveui = True
except (EOFError, OSError):
disconnect_client(self, fds) #出现异常则断开客户连接
if not self.timeout == -1.0 and not self.haveui and self.lastui and self.timeout and (self.lastui + self.timeout) < time.time():
print("Server timeout, exiting.")
self.quit = True
if self.command_channel in ready: #命令通道就绪，从命令通道中读取一条命令
try:
command = self.command_channel.get()
except EOFError:
# Client connection shutting down
ready = []
disconnect_client(self, fds) #出现异常则断开客户连接
continue
if command[0] == "terminateServer":
self.quit = True
continue
try:个
print("Running command %s" % command)
self.command_channel_reply.send(self.cooker.command.runCommand(command)) #执行接收到的命令并且构造响应 except Exception as e: logger.exception(‘Exception in server main event loop running command %s (%s)‘ % (command, str(e)))
if self.xmlrpc in ready: #xmlrpc就绪，处理xmlrpc请求。 self.xmlrpc.handle_requests()
ready = self.idle_commands(.1, fds) #从套接字中获取就绪的套接字
3. 退出清理
print("Exiting")
# Remove the socket file so we don‘t get any more connections to avoid races
os.unlink(self.sockname) #删除域套接字文件
self.sock.close() #关闭本套接字，这里顺序上存疑
try:
self.cooker.shutdown(True) #关闭cooker
self.cooker.notifier.stop() #停止notify
self.cooker.confignotifier.stop() #停止confignotify
except:
pass
self.cooker.post_serve() #调用cooker.post_serve(),这个在后面进行分解
# Finally release the lockfile but warn about other processes holding it open
lock = self.bitbake_lock
lockfile = lock.name
lock.close() #关闭bitbake_lock
lock = None
while not lock:
with bb.utils.timeout(3):
lock = bb.utils.lockfile(lockfile, shared=False, retry=False, block=True)
if not lock:
# Some systems may not have lsof available
procs = None
try:
procs = subprocess.check_output(["lsof", ‘-w‘, lockfile], stderr=subprocess.STDOUT)
except OSError as e:
if e.errno != errno.ENOENT:
raise
if procs is None:
# Fall back to fuser if lsof is unavailable
try:
procs = subprocess.check_output(["fuser", ‘-v‘, lockfile], stderr=subprocess.STDOUT)
except OSError as e:
if e.errno != errno.ENOENT:
raise
msg = "Delaying shutdown due to active processes which appear to be holding bitbake.lock"
if procs:
msg += ":\n%s" % str(procs)
print(msg)
return
# We hold the lock so we can remove the file (hide stale pid data)
bb.utils.remove(lockfile)
bb.utils.unlockfile(lock)
原文地址：https://www.cnblogs.com/shortnil/p/9866808.html
时间： 2024-08-30 14:22:32