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Merged
histrio merged 10 commits into from
Jul 15, 2025
Merged

Refactoring 2025 #59

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1367573
Initial
histrio Jul 15, 2025
c7d99a0
Intrioduced check_output with timeout
histrio Jul 15, 2025
0833972
Forgotten change
histrio Jul 15, 2025
79753fd
Let's not try to read too long notes
histrio Jul 15, 2025
6409740
Fixed flake8 complains
histrio Jul 15, 2025
ac7b6ce
Fixed unused constant
histrio Jul 15, 2025
67d1dfc
Tidy up imports
histrio Jul 15, 2025
e7dfe88
Do not swallow too broad exceptions
histrio Jul 15, 2025
2b50de3
More usefull exceptions
histrio Jul 15, 2025
c87a2ba
py27 compatible subprocess error
histrio Jul 15, 2025
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12 changes: 8 additions & 4 deletions tests/test_kernelcare.py
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Original file line number Diff line number Diff line change
Expand Up @@ -26,18 +26,18 @@ def tests_get_patched_data(mock_system, tmpdir):
libcare_ctl.ensure(file=0)
assert uchecker.get_patched_data() == set()
libcare_ctl.ensure(file=1)
with mock.patch('uchecker.check_output', return_value='{}'):
with mock.patch('uchecker.check_output_with_timeout', return_value='{}'):
assert uchecker.get_patched_data() == set()
with mock.patch('uchecker.check_output', return_value='{wrong-format}'):
with mock.patch('uchecker.check_output_with_timeout', return_value='{wrong-format}'):
assert uchecker.get_patched_data() == set()
with mock.patch('uchecker.check_output', return_value=LIBCARE_INFO_OUT):
with mock.patch('uchecker.check_output_with_timeout', return_value=LIBCARE_INFO_OUT):
assert uchecker.get_patched_data() == {
(20025, '4cf1939f660008cfa869d8364651f31aacd2c1c4'),
(20025, 'f9fafde281e0e0e2af45911ad0fa115b64c2cea8'),
(20026, '4cf1939f660008cfa869d8364651f31aacd2c1c4'),
(20026, 'f9fafde281e0e0e2af45911ad0fa115b64c2ce10')
}
with mock.patch('uchecker.check_output', side_effect=IOError('test')):
with mock.patch('uchecker.check_output_with_timeout', side_effect=IOError('test')):
assert uchecker.get_patched_data() == set()
with mock.patch('uchecker.LIBCARE_CLIENT', '/file/that/not/exists/'):
assert uchecker.get_patched_data() == set()
Expand Down Expand Up @@ -114,6 +114,10 @@ def test_normalize_bytes():
assert uchecker.normalize(b"hello") == "hello"


def test_normalize_unicode():
assert uchecker.normalize(u"hello") == "hello"


def test_normalize_non_string_bytes():
with pytest.raises(AttributeError):
uchecker.normalize(123)
89 changes: 62 additions & 27 deletions uchecker.py
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Original file line number Diff line number Diff line change
Expand Up @@ -31,6 +31,7 @@
import re
import json
import struct
import signal
import logging
import subprocess

Expand All @@ -44,6 +45,11 @@
NT_GO_BUILD_ID = 4
IGNORED_PATHNAME = ["[heap]", "[stack]", "[vdso]", "[vsyscall]", "[vvar]"]

ELF_MAGIC_BYTES = b'\x7fELF\x02\x01'
PROC_TIMEOUT = 30
MAX_NOTE_SIZE = 4096
BYTE_ALIGNMENT = 4

Vma = namedtuple('Vma', 'offset size start end')
Map = namedtuple('Map', 'addr perm offset dev inode pathname flag')

Expand All @@ -68,20 +74,47 @@ def normalize(data, encoding='utf-8'):
return data.encode(encoding)


def check_output(*args, **kwargs):
""" Backported implementation for check_output.
"""
out = ''
def check_output_with_timeout(*args, **kwargs):
"""Enhanced check_output with timeout support for Python 2/3."""
timeout = kwargs.pop('timeout', PROC_TIMEOUT)

# SubprocessError is not available in Python 2.7
SubprocessError = (getattr(subprocess, 'SubprocessError', OSError), OSError)

try:
p = subprocess.Popen(stdout=subprocess.PIPE, stderr=subprocess.PIPE,
*args, **kwargs)
out, err = p.communicate()
if err or p.returncode != 0:
raise OSError("{0} ({1})".format(err, p.returncode))
except OSError as e:
logging.debug('Subprocess `%s %s` error: %s',
args, kwargs, e)
return normalize(out)

def timeout_handler(signum, frame):
raise OSError("Command timed out")

if hasattr(signal, 'SIGALRM'):
old_handler = signal.signal(signal.SIGALRM, timeout_handler)
signal.alarm(timeout)

try:
p = subprocess.Popen(stdout=subprocess.PIPE, stderr=subprocess.PIPE,
*args, **kwargs)
out, err = p.communicate()

if hasattr(signal, 'SIGALRM'):
signal.alarm(0)
signal.signal(signal.SIGALRM, old_handler)

if err or p.returncode != 0:
raise OSError("{0} ({1})".format(normalize(err), p.returncode))
return normalize(out)

except OSError:
if hasattr(signal, 'SIGALRM'):
signal.alarm(0)
signal.signal(signal.SIGALRM, old_handler)
raise

except SubprocessError as e:
logging.error('Subprocess error running %s: %s', args, str(e))
return ''
except Exception as e:
logging.critical('Unexpected error running %s: %s', args, str(e))
raise


def _linux_distribution(*args, **kwargs):
Expand All @@ -92,11 +125,11 @@ def _linux_distribution(*args, **kwargs):
Additional parameters like `full_distribution_name` are not implemented.
"""

uname_raw = check_output(['uname', '-rs'])
uname_raw = check_output_with_timeout(['uname', '-rs'])
uname_name, _, uname_version = uname_raw.partition(' ')
uname = {'id': uname_name.lower(), 'name': uname_name, 'release': uname_version}

os_release_raw = check_output(['cat', '/etc/os-release'])
os_release_raw = check_output_with_timeout(['cat', '/etc/os-release'])
os_release = {}
for line in os_release_raw.split('\n'):
k, _, v = line.partition('=')
Expand All @@ -110,7 +143,7 @@ def _linux_distribution(*args, **kwargs):
elif k in ('pretty_name', ):
os_release['pretty_name_version_id'] = v.split(' ')[-1]

lsb_release_raw = check_output(['lsb_release', '-a'])
lsb_release_raw = check_output_with_timeout(['lsb_release', '-a'])
lsb_release = {}
for line in lsb_release_raw.split('\n'):
k, _, v = line.partition(':')
Expand All @@ -122,11 +155,11 @@ def _linux_distribution(*args, **kwargs):
elif k in ('distributor id', ):
lsb_release['distributor_id'] = v
elif k in ('description', ):
lsb_release['desciption_version_id'] = 'test'
lsb_release['description_version_id'] = v.split(' ')[-1] if v else ''

for dist_file in sorted(check_output(['ls', '/etc']).split('\n')):
for dist_file in sorted(check_output_with_timeout(['ls', '/etc']).split('\n')):
if (dist_file.endswith('-release') or dist_file.endswith('_version')):
distro_release_raw = check_output(['cat', os.path.join('/etc', dist_file)])
distro_release_raw = check_output_with_timeout(['cat', os.path.join('/etc', dist_file)])
if distro_release_raw:
break

Expand Down Expand Up @@ -194,7 +227,7 @@ def get_patched_data():
return result

try:
std_out = check_output([LIBCARE_CLIENT, 'info', '-j'])
std_out = check_output_with_timeout([LIBCARE_CLIENT, 'info', '-j'])
for line in std_out.splitlines():
try:
item = json.loads(line)
Expand Down Expand Up @@ -260,7 +293,7 @@ def get_build_id(fileobj):
e_shentsize, e_shnum, e_shstrndx) = hdr

# Not an ELF file
if not e_ident.startswith(b'\x7fELF\x02\x01'):
if not e_ident.startswith(ELF_MAGIC_BYTES):
raise NotAnELFException("Wrong header")

# No program headers
Expand All @@ -285,13 +318,15 @@ def get_build_id(fileobj):
n_namesz, n_descsz, n_type = struct.unpack(ELF_NHDR, nhdr)

# 4-byte align
if n_namesz % 4:
n_namesz = ((n_namesz // 4) + 1) * 4
if n_descsz % 4:
n_descsz = ((n_descsz // 4) + 1) * 4
if n_namesz % BYTE_ALIGNMENT:
n_namesz = ((n_namesz // BYTE_ALIGNMENT) + 1) * BYTE_ALIGNMENT
if n_descsz % BYTE_ALIGNMENT:
n_descsz = ((n_descsz // BYTE_ALIGNMENT) + 1) * BYTE_ALIGNMENT

logging.debug("n_type: %d, n_namesz: %d, n_descsz: %d)",
n_type, n_namesz, n_descsz)
if n_namesz > MAX_NOTE_SIZE or n_descsz > MAX_NOTE_SIZE:
raise BuildIDParsingException("Note section too large")
fileobj.read(n_namesz)
desc = struct.unpack("<{0}B".format(n_descsz), fileobj.read(n_descsz))
if n_type is not None:
Expand Down Expand Up @@ -419,10 +454,10 @@ def iter_proc_lib():
with get_fileobj(pid, inode, pathname) as fileobj:
cache[inode] = get_build_id(fileobj)
except (NotAnELFException, BuildIDParsingException, IOError) as err:
logging.info("Can't read buildID from {0}: {1}".format(pathname, repr(err)))
logging.info("Can't read buildID from %s: %s", pathname, repr(err))
cache[inode] = None
except Exception as err:
logging.error("Can't read buildID from {0}: {1}".format(pathname, repr(err)))
logging.error("Can't read buildID from %s: %s", pathname, repr(err))
cache[inode] = None
build_id = cache[inode]
yield pid, os.path.basename(pathname), build_id
Expand Down