systemd-dashboard

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import itertools as it, operator as op, functools as ft
import os, sys, re, errno, collections as cs, pathlib as pl


def systemd_state_dump(machines=False):
	'Fetch systemd state dump via libsystemd sd-bus API.'
	import os, ctypes as ct

	class sd_bus(ct.Structure): pass
	class sd_bus_error(ct.Structure):
		_fields_ = [('name', ct.c_char_p), ('message', ct.c_char_p), ('need_free', ct.c_int)]
	class sd_bus_msg(ct.Structure): pass

	lib = ct.CDLL('libsystemd.so')

	def run(call, *args, sig=None, check=True):
		func = getattr(lib, call)
		if sig: func.argtypes = sig
		res = func(*args)
		if check and res < 0: raise OSError(-res, os.strerror(-res))
		return res

	bus = ct.POINTER(sd_bus)()
	run( 'sd_bus_open_system', ct.byref(bus),
		sig=[ct.POINTER(ct.POINTER(sd_bus))] )

	error = sd_bus_error()
	reply = ct.POINTER(sd_bus_msg)()

	machine_names = list()
	if machines:
		run( 'sd_bus_call_method',
			bus,
			b'org.freedesktop.machine1',
			b'/org/freedesktop/machine1',
			b'org.freedesktop.machine1.Manager',
			b'ListMachines',
			ct.byref(error),
			ct.byref(reply),
			b'',
			sig=[
				ct.POINTER(sd_bus),
				ct.c_char_p, ct.c_char_p, ct.c_char_p, ct.c_char_p,
				ct.POINTER(sd_bus_error),
				ct.POINTER(ct.POINTER(sd_bus_msg)),
				ct.c_char_p ] )
		machine_info = list(ct.c_char_p() for n in range(4))
		machine_info_refs = list(map(ct.byref, machine_info))
		run( 'sd_bus_message_enter_container',
			reply, b'a', b'(ssso)',
			sig=[ct.POINTER(sd_bus_msg), ct.c_char, ct.c_char_p] )
		while True:
			n = run( 'sd_bus_message_read',
				reply, b'(ssso)', *machine_info_refs,
				sig=[ ct.POINTER(sd_bus_msg), ct.c_char_p,
					ct.POINTER(ct.c_char_p), ct.POINTER(ct.c_char_p),
					ct.POINTER(ct.c_char_p), ct.POINTER(ct.c_char_p) ] )
			if not n: break
			name, cls, unit, path = list(v.value.decode() for v in machine_info)
			machine_names.append(name)

	def get_state_dump():
		run( 'sd_bus_call_method',
			bus,
			b'org.freedesktop.systemd1',
			b'/org/freedesktop/systemd1',
			b'org.freedesktop.systemd1.Manager',
			b'Dump',
			ct.byref(error),
			ct.byref(reply),
			b'',
			sig=[
				ct.POINTER(sd_bus),
				ct.c_char_p, ct.c_char_p, ct.c_char_p, ct.c_char_p,
				ct.POINTER(sd_bus_error),
				ct.POINTER(ct.POINTER(sd_bus_msg)),
				ct.c_char_p ] )
		dump = ct.c_char_p()
		run( 'sd_bus_message_read', reply, b's', ct.byref(dump),
			sig=[ct.POINTER(sd_bus_msg), ct.c_char_p, ct.POINTER(ct.c_char_p)] )
		return dump.value.decode()

	def bus_close():
		run('sd_bus_flush_close_unref', bus, check=False)

	state = dict(_host=get_state_dump())
	bus_close()

	for name in machine_names:
		if name.startswith('.'): continue
		try:
			run( 'sd_bus_open_system_machine',
				ct.byref(bus), name.encode(),
				sig=[ct.POINTER(ct.POINTER(sd_bus)), ct.c_char_p] )
		except OSError as err:
			if err.errno == errno.ENOENT: continue # old machine without such link
			raise OSError(err.errno, f'machine={name} :: {str(err)}') from None
		state[name] = get_state_dump()
		bus_close()

	return state


class SDProps(cs.UserDict):

	def __init__(self, *args, **kwargs):
		super().__init__(*args, **kwargs)
		self.fix_camelcase()
		self.split_qualifiers()

	def fix_camelcase(self):
		for k in list(self.keys()):
			k_new = k
			if ' ' in k: k_new = k_new.replace(' ', '_')
			elif not (k.islower() or k.isupper()):
				k_new = re.sub( r'([A-Z]{2,})([A-Z][a-z])',
					lambda m: ('_'+m.group(1)+'_'+m.group(2)).lower(), k_new )
				k_new = re.sub(r'[A-Z]+', lambda m: '_'+m.group(0).lower(), k_new)
			k_new = re.sub(r'_+', '_', k_new.replace('/', '_').strip('_').lower())
			if k_new == k: continue
			assert k_new not in self, [k_new, self.get(k_new)]
			self[k_new] = self.pop(k)
		for k, v in list(self.items()):
			if len(v) == 1 and isinstance(v[0], dict):
				SDProps.fix_camelcase(v[0])

	def split_qualifiers(self):
		# Some values have "(origin-X destination-Y ...)" qualifiers at the end
		# Split those into separate _origin/_destination sub-props
		for k, v_list in list(self.items()):
			sks = cs.defaultdict(list)
			for n, v in enumerate(v_list):
				try:
					u, q = v.split(None, 1)
					if not (q[0] == '(' and q[-1] == ')'): continue
				except: continue
				for sk, v in (q.split('-', 1) for q in q[1:-1].split()):
					sks[f'{k}_{sk.lower()}'].append(v.lower())
				v_list[n] = u
			if len(v_list) > 1: continue # just strip q for multi-value props
			for sk, v_list in sks.items():
				if sk in self: raise RuntimeError(f'Conflicting qualifier subkey {sk!r} in: {self}')
				self[sk] = v_list

	def __getattr__(self, k):
		if k.endswith('_N'): # same attr with fallback to string
			k = k[:-2]
			if k not in self: return ''
		v_list = self[k]
		assert len(v_list) == 1, v_list
		return v_list[0]


def systemd_state_dump_parse(state_map_str, prefix_fmt='{name}/', **parse_kws):
	state = dict()
	for name, state_str in state_map_str.items():
		try: machine_state = ssd_parse_machine(state_str, **parse_kws)
		except Exception as err:
			machine = f'machine {name!r}' if name != '_host' else 'host'
			print(
				f'ERROR: Failed to parse state-dump ({len(state_str):,d} B)'
				f' for {machine}: [{err.__class__.__name__}] {err}', file=sys.stderr )
			raise
		prefix = prefix_fmt.format(name=name)
		for unit, props in machine_state.items():
			unit_key = prefix + unit
			assert unit_key not in state, [name, unit, unit_path]
			state[unit_key] = props
	return state

def ssd_parse_machine(state_str, filter_prop=None, filter_unit=None):
	state_lines = iter(state_str.splitlines())
	state_lines = it.dropwhile(lambda line: re.search(
		r'^(Manager:|Features:|Subscribed:|Timestamp) ', line ), state_lines)
	if not filter_prop: filter_prop = lambda k: True
	if not filter_unit: filter_unit = lambda u: True

	state, unit, props, prop_sub = dict(), None, None, None
	for line in it.chain(state_lines, ['-> Unit END:']):
		line = re.sub(r'^Limit\t(\S+)', r'\tLimit\1', line) # issue-9846 in systemd-239
		line = re.sub(r'^(\tOnTimeZoneChange) ', r'\1: ', line) # issue-14151 in systemd-243
		line = re.sub(r'^(\S+)\t:', r'\t\1:', line) # issue-19524 in systemd-248

		if prop_sub is not None:
			k, indent, v = prop_sub
			m = (
				re.search(r'^{}\s+(.*)(?::\s*|=)(.*)$'.format(re.escape(indent)), line)
				if filter_prop(k) else None )
			if m:
				sk, sv = m.groups()
				assert sk not in prop_sub, [prop_sub, sk]
				if filter_prop(sk): v[sk] = sv
				continue
			else:
				if k: props.setdefault(k, list()).append(v)
				prop_sub = None

		if props is not None:
			m = re.search(r'^(\s+)(->|→) (Exec\w+):$', line)
			if m:
				prop_sub = m.group(3), m.group(1), dict()
				continue
			m = re.search(r'^(\s+)(->|→) Job (\d+):$', line)
			if m:
				prop_sub = None, m.group(1), dict() # discarded later
				continue
			m = re.search(r'^\s+(.*?)(?::\s*|=)(.*)$', line)
			if m:
				k, v = m.groups()
				if filter_prop(k): props.setdefault(k, list()).append(v)
				continue
			if prop_sub:
				prop_sub, (k, indent, v) = None, prop_sub
				if filter_prop(k): props.setdefault(k, list()).append(v)
			if unit:
				assert unit not in state, unit
				if filter_unit(unit): state[unit] = SDProps(props)
			props = None

		if props is None:
			m = re.search(r'^(->|→) Job (\d+):$', line)
			if m: unit, props = None, dict() # discarded later

		if props is None:
			m = re.search(r'^(->|→) Unit (.*):$', line)
			if not m: raise ValueError(repr(line))
			unit, props = m.group(2), dict()
			unit = re.sub( br'\\x([\da-f]{2})',
				lambda m: chr(int(m.group(1), 16)).encode(),
				unit.encode() ).decode()

	return state


def main(args=None):
	import argparse
	parser = argparse.ArgumentParser(
		description='systemd state tracking tool.'
			' Use "systemd-analyze dump" to get raw state dump.')
	parser.add_argument('-u', '--unit', metavar='name',
		help='Pretty-print state for specified unit name and exit.')
	parser.add_argument('-m', '--machines', action='store_true',
		help='Query and print units in each registered'
				' machine running on this host, prefixed by "{name}/".'
			' Connecting to system bus of these requires root uid.')
	parser.add_argument('-f', '--file', metavar='file',
		help='Process specified "systemd-analyze dump" file instead of getting it via dbus.')
	parser.add_argument('-x', '--exclude-regexp', metavar='regexp',
		help='Exactly like "grep -v" on the output lines, with python regexp format.')
	opts = parser.parse_args(sys.argv[1:] if args is None else args)

	if not opts.unit:
		# These are purely for performance optimization purposes.
		# On hosts with containers, dumps can get pretty large and slow to parse.
		filter_prop_keys = { 'Type', 'Source Path', 'StandardInput',
			'Transient', 'Unit Load State', 'Unit Active State', 'TriggeredBy' }
		filters = dict(
			filter_prop=lambda k,_set=filter_prop_keys: k in _set,
			filter_unit=lambda u: not re.search(r'\.(device|slice|scope)$', u) )
	else: filters = dict()
	out_filter = opts.exclude_regexp and re.compile(opts.exclude_regexp)

	if not opts.file:
		state_map_str = systemd_state_dump(machines=opts.machines)
	else: state_map_str = dict(_host=pl.Path(opts.file).read_text())
	state = systemd_state_dump_parse(
		state_map_str, prefix_fmt='{name}/' if opts.machines else '', **filters )

	if opts.unit:
		unit = state.get(opts.unit)
		if not unit: unit = state.get(opts.unit + '.service')
		if not unit: parser.error(f'Unit {opts.unit!r} not found in systemd state dump')
		import pprint
		pprint.pprint(unit)
		return

	for unit, s in sorted(state.items()):
		if re.search(r'\.(device|slice|scope)$', unit): continue

		# Raw dm-* numbers change, so no point tracking these
		if re.search(r'(/|^)dev-dm-\d+\.swap$', unit): continue

		# Skip any known auto-started/stopped and transient units
		# Does not skip: Unit=X from timers/sockets
		# WARNING: be sure to add all props used there to filter_prop_keys above!
		if unit.endswith('.mount') and f'{unit[:-6]}.automount' in state: continue
		if unit.endswith('.service') and ( s.standard_input_N == 'socket'
			or f'{unit[:-8]}.timer' in state or f'{unit[:-8]}.socket' in state ): continue
		if s.type_N == 'dbus': continue
		if s.source_path_N == '/proc/self/mountinfo': continue
		if s.transient_N == 'yes': continue
		if re.search(r'(/|^)user(-runtime-dir)?@\d+\.service$', unit): continue
		if ( re.search(r'(/|^)[^/@]+@[^/]+\.service$', unit)
			and s.triggered_by_N.endswith('.socket') ): continue

		if s.unit_load_state in ['error', 'not-found']: continue
		if s.unit_active_state != 'active': continue
		if out_filter and out_filter.search(unit): continue
		print(unit)

if __name__ == '__main__': sys.exit(main())