Source code
Revision control
Copy as Markdown
Other Tools
# A unix-oriented process dispatcher. Uses a single thread with select and
# waitpid to dispatch tasks. This avoids several deadlocks that are possible
# with fork/exec + threads + Python.
import errno
import os
import select
import signal
import sys
from datetime import datetime, timedelta
from .adaptor import xdr_annotate
from .progressbar import ProgressBar
from .results import NullTestOutput, TestOutput, escape_cmdline
class Task(object):
def __init__(self, test, prefix, tempdir, pid, stdout, stderr):
self.test = test
self.cmd = test.get_command(prefix, tempdir)
self.pid = pid
self.stdout = stdout
self.stderr = stderr
self.start = datetime.now()
self.out = []
self.err = []
def spawn_test(test, prefix, tempdir, passthrough, run_skipped, show_cmd):
"""Spawn one child, return a task struct."""
if not test.enable and not run_skipped:
return None
cmd = test.get_command(prefix, tempdir)
if show_cmd:
print(escape_cmdline(cmd))
if not passthrough:
(rout, wout) = os.pipe()
(rerr, werr) = os.pipe()
rv = os.fork()
# Parent.
if rv:
os.close(wout)
os.close(werr)
return Task(test, prefix, tempdir, rv, rout, rerr)
# Child.
os.close(rout)
os.close(rerr)
os.dup2(wout, 1)
os.dup2(werr, 2)
os.execvp(cmd[0], cmd)
def get_max_wait(tasks, timeout):
"""
Return the maximum time we can wait before any task should time out.
"""
# If we have a progress-meter, we need to wake up to update it frequently.
wait = ProgressBar.update_granularity()
# If a timeout is supplied, we need to wake up for the first task to
# timeout if that is sooner.
if timeout:
now = datetime.now()
timeout_delta = timedelta(seconds=timeout)
for task in tasks:
remaining = task.start + timeout_delta - now
if remaining < wait:
wait = remaining
# Return the wait time in seconds, clamped between zero and max_wait.
return max(wait.total_seconds(), 0)
def flush_input(fd, frags):
"""
Read any pages sitting in the file descriptor 'fd' into the list 'frags'.
"""
rv = os.read(fd, 4096)
frags.append(rv)
while len(rv) == 4096:
# If read() returns a full buffer, it may indicate there was 1 buffer
# worth of data, or that there is more data to read. Poll the socket
# before we read again to ensure that we will not block indefinitly.
readable, _, _ = select.select([fd], [], [], 0)
if not readable:
return
rv = os.read(fd, 4096)
frags.append(rv)
def read_input(tasks, timeout):
"""
Select on input or errors from the given task list for a max of timeout
seconds.
"""
rlist = []
exlist = []
outmap = {} # Fast access to fragment list given fd.
for t in tasks:
rlist.append(t.stdout)
rlist.append(t.stderr)
outmap[t.stdout] = t.out
outmap[t.stderr] = t.err
# This will trigger with a close event when the child dies, allowing
# us to respond immediately and not leave cores idle.
exlist.append(t.stdout)
readable = []
try:
readable, _, _ = select.select(rlist, [], exlist, timeout)
except OverflowError:
print >> sys.stderr, "timeout value", timeout
raise
for fd in readable:
flush_input(fd, outmap[fd])
def remove_task(tasks, pid):
"""
Return a pair with the removed task and the new, modified tasks list.
"""
index = None
for i, t in enumerate(tasks):
if t.pid == pid:
index = i
break
else:
raise KeyError("No such pid: {}".format(pid))
out = tasks[index]
tasks.pop(index)
return out
def timed_out(task, timeout):
"""
Return a timedelta with the amount we are overdue, or False if the timeout
has not yet been reached (or timeout is falsy, indicating there is no
timeout.)
"""
if not timeout:
return False
elapsed = datetime.now() - task.start
over = elapsed - timedelta(seconds=timeout)
return over if over.total_seconds() > 0 else False
def reap_zombies(tasks, timeout):
"""
Search for children of this process that have finished. If they are tasks,
then this routine will clean up the child. This method returns a new task
list that has had the ended tasks removed, followed by the list of finished
tasks.
"""
finished = []
while True:
try:
pid, status = os.waitpid(0, os.WNOHANG)
if pid == 0:
break
except OSError as e:
if e.errno == errno.ECHILD:
break
raise e
ended = remove_task(tasks, pid)
flush_input(ended.stdout, ended.out)
flush_input(ended.stderr, ended.err)
os.close(ended.stdout)
os.close(ended.stderr)
returncode = os.WEXITSTATUS(status)
if os.WIFSIGNALED(status):
returncode = -os.WTERMSIG(status)
finished.append(
TestOutput(
ended.test,
ended.cmd,
b"".join(ended.out).decode("utf-8", "replace"),
b"".join(ended.err).decode("utf-8", "replace"),
returncode,
(datetime.now() - ended.start).total_seconds(),
timed_out(ended, timeout),
{"pid": ended.pid},
)
)
return tasks, finished
def kill_undead(tasks, timeout):
"""
Signal all children that are over the given timeout. Use SIGABRT first to
generate a stack dump. If it still doesn't die for another 30 seconds, kill
with SIGKILL.
"""
for task in tasks:
over = timed_out(task, timeout)
if over:
if over.total_seconds() < 30:
os.kill(task.pid, signal.SIGABRT)
else:
os.kill(task.pid, signal.SIGKILL)
def run_all_tests(tests, prefix, tempdir, pb, options):
# Copy and reverse for fast pop off end.
tests = list(tests)
tests = tests[:]
tests.reverse()
# The set of currently running tests.
tasks = []
# Piggy back on the first test to generate the XDR content needed for all
# other tests to run. To avoid read/write races, we temporarily limit the
# number of workers.
wait_for_encoding = False
worker_count = options.worker_count
if options.use_xdr and len(tests) > 1:
# The next loop pops tests, thus we iterate over the tests in reversed
# order.
tests = list(xdr_annotate(reversed(tests), options))
tests = tests[:]
tests.reverse()
wait_for_encoding = True
worker_count = 1
while len(tests) or len(tasks):
while len(tests) and len(tasks) < worker_count:
test = tests.pop()
task = spawn_test(
test,
prefix,
tempdir,
options.passthrough,
options.run_skipped,
options.show_cmd,
)
if task:
tasks.append(task)
else:
yield NullTestOutput(test)
timeout = get_max_wait(tasks, options.timeout)
read_input(tasks, timeout)
kill_undead(tasks, options.timeout)
tasks, finished = reap_zombies(tasks, options.timeout)
# With Python3.4+ we could use yield from to remove this loop.
for out in finished:
yield out
if wait_for_encoding and out.test == test:
assert test.selfhosted_xdr_mode == "encode"
wait_for_encoding = False
worker_count = options.worker_count
# If we did not finish any tasks, poke the progress bar to show that
# the test harness is at least not frozen.
if len(finished) == 0:
pb.poke()