[CRIU] [PATCH] test, pipes: Exhaustive test of shared pipes

[Pavel Emelyanov]

On 12/12/2016 01:04 PM, Kirill Tkhai wrote:
> On 09.12.2016 16:59, Pavel Emelyanov wrote:
>> So, here's the next test that just enumerates all possible states and checks
>> that CRIU C/R-s it well. This time -- pipes. The goal of the test is to load
>> the fd-sharing engine, so pipes are chosen, as they not only generate shared
>> struct files, but also produce 2 descriptors in CRIU's fdesc->open callback
>> which is handled separately.
>>
>> It's implemented slightly differently from the unix test, since we don't want
>> to check sequences of syscalls on objects, we need to check the task to pipe
>> relations in all possible ways.
>>
>> The 'state' is several tasks, several pipes and each generated test includes
>> pipe ends sitting in all possible combinations in the tasks' FDTs.
>>
>> Also note, that states, that seem to be equal to each other, e.g. pipe between
>> tasks A->B and pipe B->A, are really different as CRIU picks the pipe-restorer
>> based in task PIDs. So whether the picked task has read end or write end at 
>> his FDT makes a difference on restore.
>>
>> Number of tasks is limited with --tasks option, number of pipes with the
>> --pipes one. Test just runs all -- generates states, makes them and C/R-s
>> them. To check the restored result the /proc/pid/fd/ and /proc/pid/fdinfo/
>> for all restored tasks is analyzed.
>>
>> Right now CRIU works OK for --tasks 2 --pipes 2 (for more -- didn't check).
>> Kirill, please, check that your patches pass this test.
> 
> I applied the test to criu-dev (without my patches) and run it:
> 
> ~/criu# python ./test/exhaustive/pipe.py --tasks 2 --pipes 2
> Checking [(0, 0), (0, 0)]
> 	Make pipes
> 		Make pipes for 0
> 		Make pipes for 1
> 	Wait for C/R
> C/R test
> `- dump fail
> Wake up test
> Done (1, pid == 23208)
> FAIL
> 
> Hm... Do I run it in a wrong way?

Did you build criu before running the test?

>> TODO:
>>
>>  - Randomize FDs under which tasks see the pipes. Now all tasks if they have
>>    some pipe, all see it under the same set of FDs.
>>
>> Signed-off-by: Pavel Emelyanov <xemul at virtuozzo.com>
>> ---
>>  test/exhaustive/pipe.py | 270 ++++++++++++++++++++++++++++++++++++++++++++++++
>>  1 file changed, 270 insertions(+)
>>  create mode 100755 test/exhaustive/pipe.py
>>
>> diff --git a/test/exhaustive/pipe.py b/test/exhaustive/pipe.py
>> new file mode 100755
>> index 0000000..4e94cab
>> --- /dev/null
>> +++ b/test/exhaustive/pipe.py
>> @@ -0,0 +1,270 @@
>> +#!/usr/bin/env python
>> +
>> +import argparse
>> +import os
>> +import signal
>> +import socket
>> +import time
>> +import sys
>> +import subprocess
>> +
>> +criu_bin='../../criu/criu'
>> +
>> +def mix(nr_tasks, nr_pipes):
>> +	# Returned is the list of combinations.
>> +	# Each combination is the lists of pipe descriptors.
>> +	# Each pipe descriptor is a 2-elemtn tuple, that contains values 
>> +	# for R and W ends of pipes, each being a bit-field denoting in 
>> +	# which tasks the respective end should be opened or not.
>> +
>> +	# First -- make a full set of combinations for a single pipe.
>> +	max_idx = 1 << nr_tasks
>> +	pipe_mix = [[(r, w)] for r in xrange(0, max_idx) for w in xrange(0, max_idx)]
>> +
>> +	# Now, for every pipe throw another one into the game making
>> +	# all possible combinations of what was seen before with the
>> +	# newbie.
>> +	pipes_mix = pipe_mix
>> +	for t in xrange(1, nr_pipes):
>> +		pipes_mix = [ o + n for o in pipes_mix for n in pipe_mix ]
>> +
>> +	return pipes_mix
>> +
>> +
>> +# Called by a test sub-process. It just closes the not needed ends
>> +# of pipes and sleeps waiting for death.
>> +def make_pipes(task_nr, nr_pipes, pipes, comb, status_pipe):
>> +	print '\t\tMake pipes for %d' % task_nr
>> +	# We need to make sure that pipes have their
>> +	# ends according to comb for task_nr
>> +
>> +	for i in xrange(0, nr_pipes):
>> +		# Read end
>> +		if not (comb[i][0] & (1 << task_nr)):
>> +			os.close(pipes[i][0])
>> +		# Write end
>> +		if not (comb[i][1] & (1 << task_nr)):
>> +			os.close(pipes[i][1])
>> +
>> +	os.write(status_pipe, '0')
>> +	os.close(status_pipe)
>> +	while True:
>> +		time.sleep(100)
>> +
>> +
>> +def get_pipe_ino(pid, fd):
>> +	try:
>> +		return os.stat('/proc/%d/fd/%d' % (pid, fd)).st_ino
>> +	except:
>> +		return None
>> +
>> +
>> +def get_pipe_rw(pid, fd):
>> +	for l in open('/proc/%d/fdinfo/%d' % (pid, fd)):
>> +		if l.startswith('flags:'):
>> +			f = l.split(None, 1)[1][-2]
>> +			if f == '0':
>> +				return 0 # Read
>> +			elif f == '1':
>> +				return 1 # Write
>> +			break
>> +
>> +	raise Exception('Unexpected fdinfo contents')
>> +
>> +
>> +def check_pipe_y(pid, fd, rw, inos):
>> +	ino = get_pipe_ino(pid, fd)
>> +	if ino == None:
>> +		return 'missing '
>> +	if not inos.has_key(fd):
>> +		inos[fd] = ino
>> +	elif inos[fd] != ino:
>> +		return 'wrong '
>> +	mod = get_pipe_rw(pid, fd)
>> +	if mod != rw:
>> +		return 'badmode '
>> +	return None
>> +
>> +
>> +def check_pipe_n(pid, fd):
>> +	ino = get_pipe_ino(pid, fd)
>> +	if ino == None:
>> +		return None
>> +	else:
>> +		return 'present '
>> +
>> +
>> +def check_pipe_end(kids, fd, comb, rw, inos):
>> +	t_nr = 0
>> +	for t_pid in kids:
>> +		if comb & (1 << t_nr):
>> +			res = check_pipe_y(t_pid, fd, rw, inos)
>> +		else:
>> +			res = check_pipe_n(t_pid, fd)
>> +		if res != None:
>> +			return res + 'kid(%d)' % t_nr
>> +		t_nr += 1
>> +	return None
>> +
>> +
>> +def check_pipe(kids, fds, comb, inos):
>> +	for e in (0, 1): # 0 == R, 1 == W, see get_pipe_rw()
>> +		res = check_pipe_end(kids, fds[e], comb[e], e, inos)
>> +		if res != None:
>> +			return res + 'end(%d)' % e
>> +	return None
>> +
>> +def check_pipes(kids, pipes, comb):
>> +	# Kids contain pids
>> +	# Pipes contain pipe FDs
>> +	# Comb contain list of pairs of bits for RW ends
>> +	p_nr = 0
>> +	p_inos = {}
>> +	for p_fds in pipes:
>> +		res = check_pipe(kids, p_fds, comb[p_nr], p_inos)
>> +		if res != None:
>> +			return res + 'pipe(%d)' % p_nr
>> +		p_nr += 1
>> +
>> +	return None
>> +
>> +
>> +# Run by test main process. It opens pipes, then forks kids that
>> +# will contain needed pipe ends, then report back that it's ready
>> +# and waits for a signal (unix socket message) to start checking
>> +# the kids' FD tables.
>> +def make_comb(comb, opts, status_pipe):
>> +	print '\tMake pipes'
>> +	# 1st -- make needed pipes
>> +	pipes = []
>> +	for p in xrange(0, opts.pipes):
>> +		pipes.append(os.pipe())
>> +
>> +	# Fork the kids that'll make pipes
>> +	kc_pipe = os.pipe()
>> +	kids = []
>> +	for t in xrange(0, opts.tasks):
>> +		pid = os.fork()
>> +		if pid == 0:
>> +			os.close(status_pipe)
>> +			os.close(kc_pipe[0])
>> +			make_pipes(t, opts.pipes, pipes, comb, kc_pipe[1])
>> +			sys.exit(1)
>> +		kids.append(pid)
>> +
>> +	os.close(kc_pipe[1])
>> +	for p in pipes:
>> +		os.close(p[0])
>> +		os.close(p[1])
>> +
>> +	# Wait for kids to get ready
>> +	k_res = ''
>> +	while True:
>> +		v = os.read(kc_pipe[0], 16)
>> +		if v == '':
>> +			break
>> +		k_res += v
>> +	os.close(kc_pipe[0])
>> +
>> +	ex_code = 1
>> +	if k_res == '0' * opts.tasks:
>> +		print '\tWait for C/R'
>> +		cmd_sk = socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM, 0)
>> +		cmd_sk.bind('\0CRIUPCSK')
>> +
>> +		# Kids are ready, so is socket for kicking us. Notify the
>> +		# parent task that we are good to go.
>> +		os.write(status_pipe, '0')
>> +		os.close(status_pipe)
>> +		v = cmd_sk.recv(16)
>> +		if v == '0':
>> +			print '\tCheck pipes'
>> +			res = check_pipes(kids, pipes, comb)
>> +			if res == None:
>> +				ex_code = 0
>> +			else:
>> +				print '\tFAIL %s' % res
>> +
>> +	# Just kill kids, all checks are done by us, we don't need'em any more
>> +	for t in kids:
>> +		os.kill(t, signal.SIGKILL)
>> +		os.waitpid(t, 0)
>> +
>> +	return ex_code
>> +
>> +
>> +def cr_test(pid):
>> +	print 'C/R test'
>> +	img_dir = 'pimg_%d' % pid
>> +	try:
>> +		os.mkdir(img_dir)
>> +		subprocess.check_call([criu_bin, 'dump', '-t', '%d' % pid, '-D', img_dir, '-o', 'dump.log', '-v4', '-j'])
>> +	except:
>> +		print '`- dump fail'
>> +		return False
>> +
>> +	try:
>> +		os.waitpid(pid, 0)
>> +		subprocess.check_call([criu_bin, 'restore', '-D', img_dir, '-o', 'rst.log', '-v4', '-j', '-d', '-S'])
>> +	except:
>> +		print '`- restore fail'
>> +		return False
>> +
>> +	return True
>> +
>> +
>> +def run(comb, opts):
>> +	print 'Checking %r' % comb
>> +	cpipe = os.pipe()
>> +	pid = os.fork()
>> +	if pid == 0:
>> +		os.close(cpipe[0])
>> +		ret = make_comb(comb, opts, cpipe[1])
>> +		sys.exit(ret)
>> +
>> +	# Wait for the main process to get ready
>> +	os.close(cpipe[1])
>> +	res = os.read(cpipe[0], 16)
>> +	os.close(cpipe[0])
>> +
>> +	if res == '0':
>> +		res = cr_test(pid)
>> +
>> +		print 'Wake up test'
>> +		s = socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM, 0)
>> +		if res:
>> +			res = '0'
>> +		else:
>> +			res = 'X'
>> +		try:
>> +			# Kick the test to check its state
>> +			s.sendto(res, '\0CRIUPCSK')
>> +		except:
>> +			# Restore might have failed or smth else happenned
>> +			os.kill(pid, signal.SIGKILL)
>> +		s.close()
>> +
>> +	# Wait for the guy to exit and get the result (PASS/FAIL)
>> +	p, st = os.waitpid(pid, 0)
>> +	if os.WIFEXITED(st):
>> +		st = os.WEXITSTATUS(st)
>> +
>> +	print 'Done (%d, pid == %d)' % (st, pid)
>> +	return st == 0
>> +
>> +
>> +p = argparse.ArgumentParser("CRIU test suite")
>> +p.add_argument("--tasks", help = "Number of tasks", default = '2')
>> +p.add_argument("--pipes", help = "Number of pipes", default = '2')
>> +opts = p.parse_args()
>> +opts.tasks = int(opts.tasks)
>> +opts.pipes = int(opts.pipes)
>> +
>> +pipe_combs = mix(opts.tasks, opts.pipes)
>> +
>> +for comb in pipe_combs:
>> +	if not run(comb, opts):
>> +		print 'FAIL'
>> +		break
>> +else:
>> +	print 'PASS'
>>
> .
>