Files
poky/bitbake/bin/bitbake-worker
Richard Purdie 1e467b333f bitbake: bitbake-worker: Guard against multiprocessing corruption of event data
In the forked child, we may use multiprocessing. There is only one event
pipe to the worker controlling process and if we're unlucky, multiple
processes can write to it at once corrupting the data by intermixing it.

We don't see this often but when we do, its quite puzzling. I suspect it
only happens in tasks which use multiprocessng (do_rootfs, do_package)
and is much more likely to happen when we have long messages, usually many
times PAGE_SIZE since PAGE_SIZE writes are atomic. This makes it much more
likely within do_roofs, when for example a subprocess lists the contents
of a rootfs.

To fix this, we give each child a Lock() object and use this to serialise
writes to the controlling worker.

(Bitbake rev: 3cb55bdf06148943960e438291f9a562857340a3)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
2015-10-01 07:43:38 +01:00

15 KiB
Executable File

#!/usr/bin/env python

import os import sys import warnings sys.path.insert(0, os.path.join(os.path.dirname(os.path.dirname(sys.argv[0])), 'lib')) from bb import fetch2 import logging import bb import select import errno import signal from multiprocessing import Lock

Users shouldn't be running this code directly

if len(sys.argv) != 2 or not sys.argv[1].startswith("decafbad"): print("bitbake-worker is meant for internal execution by bitbake itself, please don't use it standalone.") sys.exit(1)

profiling = False if sys.argv[1] == "decafbadbad": profiling = True try: import cProfile as profile except: import profile

Unbuffer stdout to avoid log truncation in the event

of an unorderly exit as well as to provide timely

updates to log files for use with tail

try: if sys.stdout.name == '': sys.stdout = os.fdopen(sys.stdout.fileno(), 'w', 0) except: pass

logger = logging.getLogger("BitBake")

try: import cPickle as pickle except ImportError: import pickle bb.msg.note(1, bb.msg.domain.Cache, "Importing cPickle failed. Falling back to a very slow implementation.")

worker_pipe = sys.stdout.fileno() bb.utils.nonblockingfd(worker_pipe)

Need to guard against multiprocessing being used in child processes

and multiple processes trying to write to the parent at the same time

worker_pipe_lock = None

handler = bb.event.LogHandler() logger.addHandler(handler)

if 0: # Code to write out a log file of all events passing through the worker logfilename = "/tmp/workerlogfile" format_str = "%(levelname)s: %(message)s" conlogformat = bb.msg.BBLogFormatter(format_str) consolelog = logging.FileHandler(logfilename) bb.msg.addDefaultlogFilter(consolelog) consolelog.setFormatter(conlogformat) logger.addHandler(consolelog)

worker_queue = ""

def worker_fire(event, d): data = "" + pickle.dumps(event) + "" worker_fire_prepickled(data)

def worker_fire_prepickled(event): global worker_queue

worker_queue = worker_queue + event
worker_flush()

def worker_flush(): global worker_queue, worker_pipe

if not worker_queue:
    return

try:
    written = os.write(worker_pipe, worker_queue)
    worker_queue = worker_queue[written:]
except (IOError, OSError) as e:
    if e.errno != errno.EAGAIN and e.errno != errno.EPIPE:
        raise

def worker_child_fire(event, d): global worker_pipe global worker_pipe_lock

data = "<event>" + pickle.dumps(event) + "</event>"
try:
    worker_pipe_lock.acquire()
    worker_pipe.write(data)
    worker_pipe_lock.release()
except IOError:
    sigterm_handler(None, None)
    raise

bb.event.worker_fire = worker_fire

lf = None #lf = open("/tmp/workercommandlog", "w+") def workerlog_write(msg): if lf: lf.write(msg) lf.flush()

def sigterm_handler(signum, frame): signal.signal(signal.SIGTERM, signal.SIG_DFL) os.killpg(0, signal.SIGTERM) sys.exit()

def fork_off_task(cfg, data, workerdata, fn, task, taskname, appends, taskdepdata, quieterrors=False): # We need to setup the environment BEFORE the fork, since # a fork() or exec*() activates PSEUDO...

envbackup = {}
fakeenv = {}
umask = None

taskdep = workerdata["taskdeps"][fn]
if 'umask' in taskdep and taskname in taskdep['umask']:
    # umask might come in as a number or text string..
    try:
         umask = int(taskdep['umask'][taskname],8)
    except TypeError:
         umask = taskdep['umask'][taskname]

# We can't use the fakeroot environment in a dry run as it possibly hasn't been built
if 'fakeroot' in taskdep and taskname in taskdep['fakeroot'] and not cfg.dry_run:
    envvars = (workerdata["fakerootenv"][fn] or "").split()
    for key, value in (var.split('=') for var in envvars):
        envbackup[key] = os.environ.get(key)
        os.environ[key] = value
        fakeenv[key] = value

    fakedirs = (workerdata["fakerootdirs"][fn] or "").split()
    for p in fakedirs:
        bb.utils.mkdirhier(p)
    logger.debug(2, 'Running %s:%s under fakeroot, fakedirs: %s' %
                    (fn, taskname, ', '.join(fakedirs)))
else:
    envvars = (workerdata["fakerootnoenv"][fn] or "").split()
    for key, value in (var.split('=') for var in envvars):
        envbackup[key] = os.environ.get(key)
        os.environ[key] = value
        fakeenv[key] = value

sys.stdout.flush()
sys.stderr.flush()

try:
    pipein, pipeout = os.pipe()
    pipein = os.fdopen(pipein, 'rb', 4096)
    pipeout = os.fdopen(pipeout, 'wb', 0)
    pid = os.fork()
except OSError as e:
    bb.msg.fatal("RunQueue", "fork failed: %d (%s)" % (e.errno, e.strerror))

if pid == 0:
    def child():
        global worker_pipe
        global worker_pipe_lock
        pipein.close()

        signal.signal(signal.SIGTERM, sigterm_handler)
        # Let SIGHUP exit as SIGTERM
        signal.signal(signal.SIGHUP, sigterm_handler)
        bb.utils.signal_on_parent_exit("SIGTERM")

        # Save out the PID so that the event can include it the
        # events
        bb.event.worker_pid = os.getpid()
        bb.event.worker_fire = worker_child_fire
        worker_pipe = pipeout
        worker_pipe_lock = Lock()

        # Make the child the process group leader and ensure no
        # child process will be controlled by the current terminal
        # This ensures signals sent to the controlling terminal like Ctrl+C
        # don't stop the child processes.
        os.setsid()
        # No stdin
        newsi = os.open(os.devnull, os.O_RDWR)
        os.dup2(newsi, sys.stdin.fileno())

        if umask:
            os.umask(umask)

        data.setVar("BB_WORKERCONTEXT", "1")
        data.setVar("BB_TASKDEPDATA", taskdepdata)
        data.setVar("BUILDNAME", workerdata["buildname"])
        data.setVar("DATE", workerdata["date"])
        data.setVar("TIME", workerdata["time"])
        bb.parse.siggen.set_taskdata(workerdata["sigdata"])
        ret = 0
        try:
            the_data = bb.cache.Cache.loadDataFull(fn, appends, data)
            the_data.setVar('BB_TASKHASH', workerdata["runq_hash"][task])

            # exported_vars() returns a generator which *cannot* be passed to os.environ.update() 
            # successfully. We also need to unset anything from the environment which shouldn't be there 
            exports = bb.data.exported_vars(the_data)
            bb.utils.empty_environment()
            for e, v in exports:
                os.environ[e] = v
            for e in fakeenv:
                os.environ[e] = fakeenv[e]
                the_data.setVar(e, fakeenv[e])
                the_data.setVarFlag(e, 'export', "1")

            if quieterrors:
                the_data.setVarFlag(taskname, "quieterrors", "1")

        except Exception as exc:
            if not quieterrors:
                logger.critical(str(exc))
            os._exit(1)
        try:
            if cfg.dry_run:
                return 0
            return bb.build.exec_task(fn, taskname, the_data, cfg.profile)
        except:
            os._exit(1)
    if not profiling:
        os._exit(child())
    else:
        profname = "profile-%s.log" % (fn.replace("/", "-") + "-" + taskname)
        prof = profile.Profile()
        try: 
            ret = profile.Profile.runcall(prof, child)
        finally:
            prof.dump_stats(profname)
            bb.utils.process_profilelog(profname)
            os._exit(ret)
else:
    for key, value in envbackup.iteritems():
        if value is None:
            del os.environ[key]
        else:
            os.environ[key] = value

return pid, pipein, pipeout

class runQueueWorkerPipe(): """ Abstraction for a pipe between a worker thread and the worker server """ def init(self, pipein, pipeout): self.input = pipein if pipeout: pipeout.close() bb.utils.nonblockingfd(self.input) self.queue = ""

def read(self):
    start = len(self.queue)
    try:
        self.queue = self.queue + self.input.read(102400)
    except (OSError, IOError) as e:
        if e.errno != errno.EAGAIN:
            raise

    end = len(self.queue)
    index = self.queue.find("</event>")
    while index != -1:
        worker_fire_prepickled(self.queue[:index+8])
        self.queue = self.queue[index+8:]
        index = self.queue.find("</event>")
    return (end > start)

def close(self):
    while self.read():
        continue
    if len(self.queue) > 0:
        print("Warning, worker child left partial message: %s" % self.queue)
    self.input.close()

normalexit = False

class BitbakeWorker(object): def init(self, din): self.input = din bb.utils.nonblockingfd(self.input) self.queue = "" self.cookercfg = None self.databuilder = None self.data = None self.build_pids = {} self.build_pipes = {}

    signal.signal(signal.SIGTERM, self.sigterm_exception)
    # Let SIGHUP exit as SIGTERM
    signal.signal(signal.SIGHUP, self.sigterm_exception)

def sigterm_exception(self, signum, stackframe):
    if signum == signal.SIGTERM:
        bb.warn("Worker recieved SIGTERM, shutting down...")
    elif signum == signal.SIGHUP:
        bb.warn("Worker recieved SIGHUP, shutting down...")
    self.handle_finishnow(None)
    signal.signal(signal.SIGTERM, signal.SIG_DFL)
    os.kill(os.getpid(), signal.SIGTERM)

def serve(self):        
    while True:
        (ready, _, _) = select.select([self.input] + [i.input for i in self.build_pipes.values()], [] , [], 1)
        if self.input in ready:
            try:
                r = self.input.read()
                if len(r) == 0:
                    # EOF on pipe, server must have terminated
                    self.sigterm_exception(signal.SIGTERM, None)
                self.queue = self.queue + r
            except (OSError, IOError):
                pass
        if len(self.queue):
            self.handle_item("cookerconfig", self.handle_cookercfg)
            self.handle_item("workerdata", self.handle_workerdata)
            self.handle_item("runtask", self.handle_runtask)
            self.handle_item("finishnow", self.handle_finishnow)
            self.handle_item("ping", self.handle_ping)
            self.handle_item("quit", self.handle_quit)

        for pipe in self.build_pipes:
            self.build_pipes[pipe].read()
        if len(self.build_pids):
            self.process_waitpid()
        worker_flush()


def handle_item(self, item, func):
    if self.queue.startswith("<" + item + ">"):
        index = self.queue.find("</" + item + ">")
        while index != -1:
            func(self.queue[(len(item) + 2):index])
            self.queue = self.queue[(index + len(item) + 3):]
            index = self.queue.find("</" + item + ">")

def handle_cookercfg(self, data):
    self.cookercfg = pickle.loads(data)
    self.databuilder = bb.cookerdata.CookerDataBuilder(self.cookercfg, worker=True)
    self.databuilder.parseBaseConfiguration()
    self.data = self.databuilder.data

def handle_workerdata(self, data):
    self.workerdata = pickle.loads(data)
    bb.msg.loggerDefaultDebugLevel = self.workerdata["logdefaultdebug"]
    bb.msg.loggerDefaultVerbose = self.workerdata["logdefaultverbose"]
    bb.msg.loggerVerboseLogs = self.workerdata["logdefaultverboselogs"]
    bb.msg.loggerDefaultDomains = self.workerdata["logdefaultdomain"]
    self.data.setVar("PRSERV_HOST", self.workerdata["prhost"])

def handle_ping(self, _):
    workerlog_write("Handling ping\n")

    logger.warn("Pong from bitbake-worker!")

def handle_quit(self, data):
    workerlog_write("Handling quit\n")

    global normalexit
    normalexit = True
    sys.exit(0)

def handle_runtask(self, data):
    fn, task, taskname, quieterrors, appends, taskdepdata = pickle.loads(data)
    workerlog_write("Handling runtask %s %s %s\n" % (task, fn, taskname))

    pid, pipein, pipeout = fork_off_task(self.cookercfg, self.data, self.workerdata, fn, task, taskname, appends, taskdepdata, quieterrors)

    self.build_pids[pid] = task
    self.build_pipes[pid] = runQueueWorkerPipe(pipein, pipeout)

def process_waitpid(self):
    """
    Return none is there are no processes awaiting result collection, otherwise
    collect the process exit codes and close the information pipe.
    """
    try:
        pid, status = os.waitpid(-1, os.WNOHANG)
        if pid == 0 or os.WIFSTOPPED(status):
            return None
    except OSError:
        return None

    workerlog_write("Exit code of %s for pid %s\n" % (status, pid))

    if os.WIFEXITED(status):
        status = os.WEXITSTATUS(status)
    elif os.WIFSIGNALED(status):
        # Per shell conventions for $?, when a process exits due to
        # a signal, we return an exit code of 128 + SIGNUM
        status = 128 + os.WTERMSIG(status)

    task = self.build_pids[pid]
    del self.build_pids[pid]

    self.build_pipes[pid].close()
    del self.build_pipes[pid]

    worker_fire_prepickled("<exitcode>" + pickle.dumps((task, status)) + "</exitcode>")

def handle_finishnow(self, _):
    if self.build_pids:
        logger.info("Sending SIGTERM to remaining %s tasks", len(self.build_pids))
        for k, v in self.build_pids.iteritems():
            try:
                os.kill(-k, signal.SIGTERM)
                os.waitpid(-1, 0)
            except:
                pass
    for pipe in self.build_pipes:
        self.build_pipes[pipe].read()

try: worker = BitbakeWorker(sys.stdin) if not profiling: worker.serve() else: profname = "profile-worker.log" prof = profile.Profile() try: profile.Profile.runcall(prof, worker.serve) finally: prof.dump_stats(profname) bb.utils.process_profilelog(profname) except BaseException as e: if not normalexit: import traceback sys.stderr.write(traceback.format_exc()) sys.stderr.write(str(e)) while len(worker_queue): worker_flush() workerlog_write("exitting") sys.exit(0)