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#!/usr/bin/python
# Collect information about a crash and create a report in /var/crash/.
# See https://wiki.ubuntu.com/AutomatedProblemReports for details.
#
# Copyright (c) 2006 Canonical Ltd.
# Author: Martin Pitt <martin.pitt@ubuntu.com>
#
# This program is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 2 of the License, or (at your
# option) any later version. See http://www.gnu.org/copyleft/pgl.html for
# the full text of the license.
import sys, os, os.path, subprocess
#################################################################
#
# functions
#
#################################################################
def _read_file(f):
'''Try to read given file and return its contents, or return a textual
error if it failed.'''
try:
return open(f).read().strip()
except IOError, e:
return 'Error: ' + str(e)
def _command_output(command, input = None, stderr = subprocess.STDOUT):
'''Try to execute given command (array) and return its stdout, or return
a textual error if it failed.'''
try:
sp = subprocess.Popen(command, stdout=subprocess.PIPE, stderr=stderr)
except OSError, e:
return 'Error: ' + str(e)
out = sp.communicate(input)[0]
if sp.returncode == 0:
return out
else:
return 'Error: command %s failed with exit code %i: %s' % (str(command), sp.returncode, out)
def write_debcontrol(file, fields):
'''Write dictionary 'fields' into the given file-like object, using Debian
control file format.'''
for k, v in fields.iteritems():
if v.find('\n') >= 0:
assert v.find('\n\n') < 0
print >> file, k + ':'
print >> file, '', v.replace('\n', '\n ')
else:
print >> file, k + ':', v
def drop_privileges(pid):
'''Change user and group to match the given target process.'''
stat = None
try:
stat = os.stat('/proc/' + pid)
except OSError:
raise ValueError, 'Invalid process ID'
os.setgid(stat.st_gid)
os.setuid(stat.st_uid)
assert os.getuid() == stat.st_uid
#################################################################
#
# classes
#
#################################################################
class InformationCollector:
'''Collect and store information about the crash.
Fields with acquired data:
- signal: signal that caused the crash
- executable: path to the crashed executable
- stacktrace: stack trace
- thread_stacktrace: thread apply all bt full
- environment: env variables from /proc/<pid>/environ
- pkg: package name and version; not present if info['executable'] does not
belong to a package
- dependencies: names and versions of depending packages; not present if
pkg is not present
- procstatus: /proc/<pid>/status
- lsb_release: lsb_release -sir
- uname: uname -a
'''
def __init__(self, pid, signal):
'Collects all information and stores them in the appropriate fields.'
self.info = {}
self.info['signal'] = signal
self.pid = pid
# determine program name
try:
self.info['executable'] = os.readlink('/proc/' + pid + '/exe')
except OSError:
return
self._get_proc()
self._get_pkg()
self._get_os()
self._get_gdb()
def _get_proc(self):
'''Collect information from /proc.'''
self.info['environment'] = _read_file('/proc/'+ self.pid + '/environ'). \
replace('\n', '\\n').replace('\0', '\n').strip()
self.info['procstatus'] = _read_file('/proc/' + self.pid + '/status')
def _get_pkg(self):
'''Check whether executable belongs to a package and determine its
name, version, and the versions of its dependencies.'''
# get dpkg -s <package> output
out = _command_output(['dpkg', '-S', self.info['executable']])
if out.startswith('Error:'):
return
pkg = out.split(':', 1)[0]
pkgstatus = _command_output(['dpkg', '-s', pkg])
if pkgstatus.startswith('Error:'):
return
for l in pkgstatus.splitlines():
if l.startswith('Version:'):
self.info['pkg'] = '%s %s' % (pkg, l.split(None, 1)[1])
break
def _get_os(self):
'''Collect information about system.'''
self.info['lsb_release'] = _command_output(['lsb_release', '-sir']).strip().replace('\n', ' ')
self.info['uname'] = _command_output(['uname', '-a']).strip()
def _get_gdb(self):
'''Get information from gdb.'''
self.info['stacktrace'] = _command_output(['gdb', '--batch', '--ex',
'bt full', self.info['executable'], self.pid],
stderr=open('/dev/null')).replace('\n\n', '\n.\n').strip()
self.info['thread_stacktrace'] = _command_output(['gdb', '--batch', '--ex',
'thread apply all bt full', self.info['executable'], self.pid],
stderr=open('/dev/null')).replace('\n\n', '\n.\n').strip()
#################################################################
#
# main
#
#################################################################
if len(sys.argv) != 3:
print 'Usage:', sys.argv[0], '<pid> <signal number>'
sys.exit(-1)
(pid, signal) = sys.argv[1:]
# Create crash report file descriptor. We prefer to create the report in
# /var/crash/ if we can create a file there; if not, we just use stderr.
try:
pidstat = os.stat('/proc/' + pid)
except OSError:
print >> sys.stderr, 'Invalid PID'
sys.exit(1)
try:
exename = os.readlink('/proc/' + pid + '/exe').replace('/', '_')
report = '/var/crash/%s.%i.crash' % (exename, pidstat.st_uid)
if os.path.exists(report):
print >> sys.stderr, 'crash-reporter: report %s already exists, doing nothing to avoid disk usage DoS' % report
sys.exit(1)
reportfile = open(report, 'w')
os.chmod(report, 0600)
os.chown(report, pidstat.st_uid, 0)
except OSError, IOError:
reportfile = sys.stderr
drop_privileges(pid)
ic = InformationCollector(pid, signal)
write_debcontrol(reportfile, ic.info)
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