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# Copyright 2016 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
import grp
import logging
import os
import pwd
import re
import shutil
import signal
import stat
import subprocess
import crash_test
from autotest_lib.client.bin import utils
from autotest_lib.client.common_lib import error
CRASHER = 'crasher_nobreakpad'
class UserCrashTest(crash_test.CrashTest):
Base class for tests that verify crash reporting for user processes. Shared
functionality includes installing a crasher executable, generating Breakpad
symbols, running the crasher process, and verifying collection and sending.
# Every crash report needs one of these to be valid.
# Reports might have these and that's OK!
REPORT_OPTIONAL_FILETYPES = {'dmp', 'log', 'proclog'}
def setup(self):
"""Copy the crasher source code under |srcdir| and build it."""
src = os.path.join(os.path.dirname(__file__), 'crasher')
dest = os.path.join(self.srcdir, 'crasher')
shutil.copytree(src, dest)
def initialize(self, expected_tag='user', expected_version=None,
"""Initialize and configure the test.
@param expected_tag: Expected tag in crash_reporter log message.
@param expected_version: Expected version included in the crash report,
or None to use the Chrome OS version.
@param force_user_crash_dir: Always look for crash reports in the crash
directory of the current user session, or
the fallback directory if no sessions.
self._expected_tag = expected_tag
self._expected_version = expected_version
self._force_user_crash_dir = force_user_crash_dir
def _prepare_crasher(self, root_path='/'):
"""Extract the crasher and set its permissions.
crasher is only gzipped to subvert Portage stripping.
@param root_path: Root directory of the chroot environment in which the
crasher is installed and run.
self._root_path = root_path
self._crasher_path = os.path.join(self.srcdir, 'crasher', CRASHER)
utils.system('cd %s; tar xzf crasher.tgz-unmasked' %
# Make sure all users (specifically chronos) have access to
# this directory and its decendents in order to run crasher
# executable as different users.
utils.system('chmod -R a+rx ' + self.bindir)
def _populate_symbols(self):
"""Set up Breakpad's symbol structure.
Breakpad's minidump processor expects symbols to be in a directory
self._symbol_dir = os.path.join(os.path.dirname(self._crasher_path),
utils.system('rm -rf %s' % self._symbol_dir)
basename = os.path.basename(self._crasher_path)
utils.system('/usr/bin/dump_syms %s > %s.sym' %
sym_name = '%s.sym' % basename
symbols = utils.read_file(sym_name)
# First line should be like:
# MODULE Linux x86 7BC3323FBDBA2002601FA5BA3186D6540 crasher_XXX
# or
# MODULE Linux arm C2FE4895B203D87DD4D9227D5209F7890 crasher_XXX
first_line = symbols.split('\n')[0]
tokens = first_line.split()
if tokens[0] != 'MODULE' or tokens[1] != 'Linux':
raise error.TestError('Unexpected symbols format: %s',
file_id = tokens[3]
target_dir = os.path.join(self._symbol_dir, basename, file_id)
os.rename(sym_name, os.path.join(target_dir, sym_name))
def _is_frame_in_stack(self, frame_index, module_name,
function_name, file_name,
line_number, stack):
"""Search for frame entries in the given stack dump text.
A frame entry looks like (alone on a line):
16 crasher_nobreakpad!main [ : 21 + 0xb]
frame_index: number of the stack frame (0 is innermost frame)
module_name: name of the module (executable or dso)
function_name: name of the function in the stack
file_name: name of the file containing the function
line_number: line number
stack: text string of stack frame entries on separate lines.
Boolean indicating if an exact match is present.
We do not care about the full function signature - ie, is it
foo or foo(ClassA *). These are present in function names
pulled by dump_syms for Stabs but not for DWARF.
regexp = (r'\n\s*%d\s+%s!%s.*\[\s*%s\s*:\s*%d\s.*\]' %
(frame_index, module_name,
function_name, file_name,
line_number))'Searching for regexp %s', regexp)
return, stack) is not None
def _verify_stack(self, stack, basename, from_crash_reporter):
# Should identify cause as SIGSEGV at address 0x16.
logging.debug('minidump_stackwalk output:\n%s', stack)
# Look for a line like:
# Crash reason: SIGSEGV
# Crash reason: SIGSEGV /0x00000000
match ='Crash reason:\s+([^\s]*)', stack)
expected_address = '0x16'
if from_crash_reporter:
# We cannot yet determine the crash address when coming
# through core files via crash_reporter.
expected_address = '0x0'
if not match or != 'SIGSEGV':
raise error.TestFail('Did not identify SIGSEGV cause')
match ='Crash address:\s+(.*)', stack)
if not match or != expected_address:
raise error.TestFail('Did not identify crash address %s' %
# Should identify crash at *(char*)0x16 assignment line
if not self._is_frame_in_stack(0, basename,
'recbomb', '', 9, stack):
raise error.TestFail('Did not show crash line on stack')
# Should identify recursion line which is on the stack
# for 15 levels
if not self._is_frame_in_stack(15, basename, 'recbomb',
'', 12, stack):
raise error.TestFail('Did not show recursion line on stack')
# Should identify main line
if not self._is_frame_in_stack(16, basename, 'main',
'', 24, stack):
raise error.TestFail('Did not show main on stack')
def _run_crasher_process(self, username, cause_crash=True, consent=True,
crasher_path=None, run_crasher=None,
expected_uid=None, expected_gid=None,
expected_exit_code=None, expected_reason=None):
"""Runs the crasher process.
Will wait up to 10 seconds for crash_reporter to report the crash.
crash_reporter_caught will be marked as true when the "Received crash
notification message..." appears. While associated logs are likely to be
available at this point, the function does not guarantee this.
@param username: Unix user of the crasher process.
@param cause_crash: Whether the crasher should crash.
@param consent: Whether the user consents to crash reporting.
@param crasher_path: Path to which the crasher should be copied before
execution. Relative to |_root_path|.
@param run_crasher: A closure to override the default |crasher_command|
invocation. It should return a tuple describing the
process, where |pid| can be None if it should be
parsed from the |output|:
def run_crasher(username, crasher_command):
return (exit_code, output, pid)
@param expected_uid: The uid the crash happens under.
@param expected_gid: The gid the crash happens under.
@param expected_exit_code:
@param expected_reason:
Expected information in crash_reporter log message.
A dictionary with keys:
returncode: return code of the crasher
crashed: did the crasher return segv error code
crash_reporter_caught: did crash_reporter catch a segv
output: stderr output of the crasher process
if crasher_path is None:
crasher_path = self._crasher_path
dest = os.path.join(self._root_path,
utils.system('cp -a "%s" "%s"' % (self._crasher_path, dest))
crasher_command = []
if username == 'root':
if expected_exit_code is None:
expected_exit_code = -signal.SIGSEGV
if expected_exit_code is None:
expected_exit_code = 128 + signal.SIGSEGV
if not run_crasher:
crasher_command.extend(['su', username, '-c'])
basename = os.path.basename(crasher_path)
if not cause_crash:
logging.debug('Running crasher: %s', crasher_command)
if run_crasher:
(exit_code, output, pid) = run_crasher(username, crasher_command)
crasher = subprocess.Popen(crasher_command,
output = crasher.communicate()[1]
exit_code = crasher.returncode
pid = None
logging.debug('Crasher output:\n%s', output)
if pid is None:
# Get the PID from the output, since || may be su's PID.
match ='pid=(\d+)', output)
if not match:
raise error.TestFail('Missing PID in crasher output')
pid = int(
if expected_uid is None:
expected_uid = pwd.getpwnam(username).pw_uid
if expected_gid is None:
expected_gid = pwd.getpwnam(username).pw_gid
if expected_reason is None:
expected_reason = 'handling' if consent else 'ignoring - no consent'
expected_message = (
('[%s] Received crash notification for %s[%d] sig 11, user %d '
'group %d (%s)') %
(self._expected_tag, basename, pid, expected_uid, expected_gid,
# Wait until no crash_reporter is running.
lambda: utils.system('pgrep -f crash_reporter.*:%s' % basename,
ignore_status=True) != 0,
'Timeout waiting for crash_reporter to finish: ' +
is_caught = False
lambda: self._log_reader.can_find(expected_message),
desc='Logs contain crash_reporter message: ' + expected_message)
is_caught = True
except utils.TimeoutError:
result = {'crashed': exit_code == expected_exit_code,
'crash_reporter_caught': is_caught,
'output': output,
'returncode': exit_code}
logging.debug('Crasher process result: %s', result)
return result
def _check_crash_directory_permissions(self, crash_dir):
stat_info = os.stat(crash_dir)
user = pwd.getpwuid(stat_info.st_uid).pw_name
group = grp.getgrgid(stat_info.st_gid).gr_name
mode = stat.S_IMODE(stat_info.st_mode)
if crash_dir == '/var/spool/crash':
expected_user = 'root'
expected_group = 'root'
expected_mode = 01755
expected_user = 'chronos'
expected_group = 'chronos'
expected_mode = 0755
if user != expected_user or group != expected_group:
raise error.TestFail(
'Expected %s.%s ownership of %s (actual %s.%s)' %
(expected_user, expected_group, crash_dir, user, group))
if mode != expected_mode:
raise error.TestFail(
'Expected %s to have mode %o (actual %o)' %
(crash_dir, expected_mode, mode))
def _check_minidump_stackwalk(self, minidump_path, basename,
stack = utils.system_output('/usr/bin/minidump_stackwalk %s %s' %
(minidump_path, self._symbol_dir))
self._verify_stack(stack, basename, from_crash_reporter)
def _check_generated_report_sending(self, meta_path, payload_path,
exec_name, report_kind,
# Now check that the sending works
result = self._call_sender_one_crash(
if (not result['send_attempt'] or not result['send_success'] or
raise error.TestFail('Report not sent properly')
if result['exec_name'] != exec_name:
raise error.TestFail('Executable name incorrect')
if result['report_kind'] != report_kind:
raise error.TestFail('Expected a %s report' % report_kind)
if result['report_payload'] != payload_path:
raise error.TestFail('Sent the wrong minidump payload %s vs %s' % (
result['report_payload'], payload_path))
if result['meta_path'] != meta_path:
raise error.TestFail('Used the wrong meta file %s vs %s' % (
result['meta_path'], meta_path))
if expected_sig is None:
if result['sig'] is not None:
raise error.TestFail('Report should not have signature')
if not 'sig' in result or result['sig'] != expected_sig:
raise error.TestFail('Report signature mismatch: %s vs %s' %
(result['sig'], expected_sig))
version = self._expected_version
if version is None:
lsb_release = utils.read_file('/etc/lsb-release')
version =
r'CHROMEOS_RELEASE_VERSION=(.*)', lsb_release).group(1)
if not ('Version: %s' % version) in result['output']:
raise error.TestFail('Missing version %s in log output' % version)
def _run_crasher_process_and_analyze(self, username,
cause_crash=True, consent=True,
crasher_path=None, run_crasher=None,
expected_uid=None, expected_gid=None,
result = self._run_crasher_process(
username, cause_crash=cause_crash, consent=consent,
crasher_path=crasher_path, run_crasher=run_crasher,
expected_uid=expected_uid, expected_gid=expected_gid,
if not result['crashed'] or not result['crash_reporter_caught']:
return result
crash_dir = self._get_crash_dir(username, self._force_user_crash_dir)
if not consent:
if os.path.exists(crash_dir):
raise error.TestFail('Crash directory should not exist')
return result
if not os.path.exists(crash_dir):
raise error.TestFail('Crash directory does not exist')
crash_contents = os.listdir(crash_dir)
basename = os.path.basename(crasher_path or self._crasher_path)
# A dict tracking files for each crash report.
crash_report_files = {}
logging.debug('Contents in %s: %s', crash_dir, crash_contents)
# Variables and their typical contents:
# basename: crasher_nobreakpad
# filename: crasher_nobreakpad.20181023.135339.16890.dmp
# ext: dmp
for filename in crash_contents:
if filename.endswith('.core'):
# Ignore core files. We'll test them later.
elif filename.startswith(basename + '.'):
ext = filename.rsplit('.', 1)[1]
logging.debug('Found crash report file (%s): %s', ext, filename)
if ext in crash_report_files:
raise error.TestFail(
'Found multiple files with .%s: %s and %s' %
(ext, filename, crash_report_files[ext]))
crash_report_files[ext] = filename
# Flag all unknown files.
raise error.TestFail('Crash reporter created an unknown file: '
'%s' % (filename,))
# Make sure we generated the exact set of files we expected.
found_filetypes = set(crash_report_files.keys())
missing_filetypes = self.REPORT_REQUIRED_FILETYPES - found_filetypes
unknown_filetypes = (found_filetypes - self.REPORT_REQUIRED_FILETYPES -
if missing_filetypes:
raise error.TestFail('crash report is missing files: %s' % (
['.' + x for x in missing_filetypes],))
if unknown_filetypes:
raise error.TestFail('crash report includes unknown files: %s' % (
[crash_report_files[x] for x in unknown_filetypes],))
# Create full paths for the logging code below.
if key in crash_report_files:
crash_report_files[key] = os.path.join(
crash_dir, crash_report_files[key])
crash_report_files[key] = None
result['minidump'] = crash_report_files['dmp']
result['basename'] = basename
result['meta'] = crash_report_files['meta']
result['log'] = crash_report_files['log']
return result
def _check_crashed_and_caught(self, result):
if not result['crashed']:
raise error.TestFail('Crasher returned %d instead of crashing' %
if not result['crash_reporter_caught']:
logging.debug('Logs do not contain crash_reporter message:\n%s',
raise error.TestFail('crash_reporter did not catch crash')
def _check_crashing_process(self, username, consent=True,
crasher_path=None, run_crasher=None,
expected_uid=None, expected_gid=None,
result = self._run_crasher_process_and_analyze(
username, consent=consent,
if not consent:
if not result['minidump']:
raise error.TestFail('crash reporter did not generate minidump')
if not self._log_reader.can_find('Stored minidump to ' +
raise error.TestFail('crash reporter did not announce minidump')