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

[Kirill Tkhai]

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?
 
> 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'
>