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Fix initialization under reduced privileges (#55)
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Also:

* fixed timed log rotation
* --log-level option added
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@etingof
etingof committed Jan 16, 2019
1 parent c8478a7 commit a690527
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Showing 6 changed files with 522 additions and 260 deletions.
6 changes: 6 additions & 0 deletions CHANGES.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,12 @@
Revision 0.4.6, released XX-01-2019
-----------------------------------

- The `--log-level` option added
- Default daemon syslog service destination to a local socket
- Fixed timed log file rotation to respect log file creation time
when computing next rotation time
- Fixed possible file permission issues by initializing pysnmp modules,
logger and variation modules subsystems under reduced user privileges
- Improve error reporting in `notification` variation module

Revision 0.4.5, released 30-12-2018
Expand Down
90 changes: 52 additions & 38 deletions scripts/pcap2dev.py
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Original file line number Diff line number Diff line change
Expand Up @@ -32,6 +32,7 @@
from snmpsim import confdir, error, log

# Defaults
PROGRAM_NAME = 'pcap2dev'
verboseFlag = True
mibSources = []
defaultMibSources = ['http://mibs.snmplabs.com/asn1/@mib@']
Expand All @@ -40,6 +41,8 @@
promiscuousMode = False
outputDir = '.'
transportIdOffset = 0
loggingMethod = ['stderr']
loggingLevel = None
variationModuleOptions = ""
variationModuleName = variationModule = None
listenInterface = captureFile = None
Expand Down Expand Up @@ -69,6 +72,7 @@
[--debug-asn1=<%s>]
[--quiet]
[--logging-method=<%s[:args]>]
[--log-level=<%s>]
[--mib-source=<url>]
[--start-object=<MIB-NAME::[symbol-name]|OID>]
[--stop-object=<MIB-NAME::[symbol-name]|OID>]
Expand All @@ -85,20 +89,22 @@
'|'.join([x for x in getattr(pysnmp_debug, 'FLAG_MAP', getattr(pysnmp_debug, 'flagMap', ()))
if x != 'mibview']),
'|'.join([x for x in getattr(pyasn1_debug, 'FLAG_MAP', getattr(pyasn1_debug, 'flagMap', ()))]),
'|'.join(log.gMap)
'|'.join(log.METHODS_MAP),
'|'.join(log.LEVELS_MAP)
)

try:
opts, params = getopt.getopt(sys.argv[1:], 'hv', [
'help', 'version', 'debug=', 'debug-snmp=', 'debug-asn1=',
'quiet', 'logging-method=', 'start-oid=', 'stop-oid=',
'quiet', 'logging-method=', 'log-level=', 'start-oid=', 'stop-oid=',
'start-object=', 'stop-object=', 'mib-source=',
'output-dir=', 'transport-id-offset=',
'capture-file=', 'listen-interface=', 'promiscuous-mode',
'packet-filter=',
'variation-modules-dir=', 'variation-module=',
'variation-module-options='
])

except Exception:
sys.stderr.write(
'ERROR: %s\r\n%s\r\n' % (sys.exc_info()[1], helpMessage))
Expand Down Expand Up @@ -145,12 +151,9 @@
pyasn1_debug.setLogger(pyasn1_debug.Debug(*opt[1].split(','), **dict(
loggerName='pcap2dev.pyasn1')))
elif opt[0] == '--logging-method':
try:
log.setLogger('pcap2dev', *opt[1].split(':'), **dict(force=True))
except error.SnmpsimError:
sys.stderr.write(
'%s\r\n%s\r\n' % (sys.exc_info()[1], helpMessage))
sys.exit(-1)
loggingMethod = opt[1].split(':')
elif opt[0] == '--log-level':
loggingLevel = opt[1]
if opt[0] == '--quiet':
verboseFlag = False
# obsolete begin
Expand Down Expand Up @@ -199,7 +202,15 @@
sys.stderr.write('ERROR: pylibpcap package is missing!\r\nGet it by running `pip install https://downloads.sourceforge.net/project/pylibpcap/pylibpcap/0.6.4/pylibpcap-0.6.4.tar.gz`\r\n%s\r\n' % helpMessage)
sys.exit(-1)

log.setLogger('pcap2dev', 'stdout')
try:
log.setLogger(PROGRAM_NAME, *loggingMethod, force=True)

if loggingLevel:
log.setLevel(loggingLevel)

except error.SnmpsimError:
sys.stderr.write('%s\r\n%s\r\n' % (sys.exc_info()[1], helpMessage))
sys.exit(1)

if isinstance(startOID, rfc1902.ObjectIdentity) or \
isinstance(stopOID, rfc1902.ObjectIdentity):
Expand All @@ -219,14 +230,14 @@

if variationModuleName:
for variationModulesDir in confdir.variation:
log.msg('Scanning "%s" directory for variation modules...' % variationModulesDir)
log.info('Scanning "%s" directory for variation modules...' % variationModulesDir)
if not os.path.exists(variationModulesDir):
log.msg('Directory "%s" does not exist' % variationModulesDir)
log.info('Directory "%s" does not exist' % variationModulesDir)
continue

mod = os.path.join(variationModulesDir, variationModuleName + '.py')
if not os.path.exists(mod):
log.msg('Variation module "%s" not found' % mod)
log.info('Variation module "%s" not found' % mod)
continue

ctx = {'path': mod, 'moduleContext': {}}
Expand All @@ -238,34 +249,36 @@
execfile(mod, ctx)

except Exception:
log.msg('Variation module "%s" execution failure: %s' % (mod, sys.exc_info()[1]))
log.error('Variation module "%s" execution failure: %s' % (mod, sys.exc_info()[1]))
sys.exit(-1)

else:
variationModule = ctx
log.msg('Variation module "%s" loaded' % variationModuleName)
log.info('Variation module "%s" loaded' % variationModuleName)
break
else:
log.msg('ERROR: variation module "%s" not found' % variationModuleName)
log.error('variation module "%s" not found' % variationModuleName)
sys.exit(-1)

# Variation module initialization

if variationModule:
log.msg('Initializing variation module...')
log.info('Initializing variation module...')
for x in ('init', 'record', 'shutdown'):
if x not in variationModule:
log.msg('ERROR: missing "%s" handler at variation module "%s"' % (x, variationModuleName))
log.error('missing "%s" handler at variation module "%s"' % (x, variationModuleName))
sys.exit(-1)
try:
variationModule['init'](options=variationModuleOptions,
mode='recording',
startOID=startOID,
stopOID=stopOID)

except Exception:
log.msg('Variation module "%s" initialization FAILED: %s' % (variationModuleName, sys.exc_info()[1]))
log.error('Variation module "%s" initialization FAILED: %s' % (variationModuleName, sys.exc_info()[1]))

else:
log.msg('Variation module "%s" initialization OK' % variationModuleName)
log.info('Variation module "%s" initialization OK' % variationModuleName)


# Data file builder
Expand Down Expand Up @@ -301,31 +314,31 @@ def formatValue(self, oid, value, **context):

if listenInterface:
if verboseFlag:
log.msg('Listening on interface %s in %spromiscuous mode' % (listenInterface, promiscuousMode is False and 'non-' or ''))
log.info('Listening on interface %s in %spromiscuous mode' % (listenInterface, promiscuousMode is False and 'non-' or ''))
try:
pcapObj.open_live(listenInterface, 65536, promiscuousMode, 1000)
except Exception:
log.msg('Error opening interface %s for snooping: %s' % (listenInterface, sys.exc_info()[1]))
log.error('Error opening interface %s for snooping: %s' % (listenInterface, sys.exc_info()[1]))
sys.exit(-1)
elif captureFile:
if verboseFlag:
log.msg('Opening capture file %s' % captureFile)
log.info('Opening capture file %s' % captureFile)
try:
pcapObj.open_offline(captureFile)
except Exception:
log.msg('Error opening capture file %s for reading: %s' % (captureFile, sys.exc_info()[1]))
log.error('Error opening capture file %s for reading: %s' % (captureFile, sys.exc_info()[1]))
sys.exit(-1)
else:
sys.stderr.write('ERROR: no capture file or live interface specified\r\n%s\r\n' % helpMessage)
sys.exit(-1)

if packetFilter:
if verboseFlag:
log.msg('Applying packet filter \"%s\"' % packetFilter)
log.info('Applying packet filter \"%s\"' % packetFilter)
pcapObj.setfilter(packetFilter, 0, 0)

if verboseFlag:
log.msg('Processing records from %s till %s' % (startOID or 'the beginning', stopOID or 'the end'))
log.info('Processing records from %s till %s' % (startOID or 'the beginning', stopOID or 'the end'))


def parsePacket(s):
Expand Down Expand Up @@ -435,19 +448,19 @@ def handlePacket(pktlen, data, timestamp):

try:
if listenInterface:
log.msg(
log.info(
'Listening on interface "%s", kill me when you are done.' % listenInterface)
while True:
pcapObj.dispatch(1, handlePacket)
elif captureFile:
log.msg('Processing capture file "%s"....' % captureFile)
log.info('Processing capture file "%s"....' % captureFile)
args = pcapObj.next()
while args:
handlePacket(*args)
args = pcapObj.next()

except (TypeError, KeyboardInterrupt):
log.msg('Shutting down process...')
log.info('Shutting down process...')

except Exception:
exc_info = sys.exc_info()
Expand All @@ -458,15 +471,15 @@ def handlePacket(pktlen, data, timestamp):
filename = os.path.join(outputDir,
context + os.path.extsep + SnmprecRecord.ext)
if verboseFlag:
log.msg('Creating simulation context %s at %s' % (context, filename))
log.info('Creating simulation context %s at %s' % (context, filename))
try:
os.mkdir(os.path.dirname(filename))
except OSError:
pass
try:
outputFile = open(filename, 'wb')
except IOError:
log.msg('ERROR: writing %s: %s' % (filename, sys.exc_info()[1]))
log.error('writing %s: %s' % (filename, sys.exc_info()[1]))
sys.exit(-1)

count = total = iteration = 0
Expand Down Expand Up @@ -523,14 +536,14 @@ def handlePacket(pktlen, data, timestamp):
moreDataNotification = sys.exc_info()[1]
if 'period' in moreDataNotification:
timeOffset += moreDataNotification['period']
log.msg(
log.info(
'%s OIDs dumped, advancing time window to %.2f sec(s)...' % (total, timeOffset))
break

except error.NoDataNotification:
pass
except error.SnmpsimError:
log.msg('ERROR: %s' % (sys.exc_info()[1],))
log.error((sys.exc_info()[1],))
continue
else:
outputFile.write(line)
Expand All @@ -545,22 +558,23 @@ def handlePacket(pktlen, data, timestamp):
outputFile.close()

if variationModule:
log.msg('Shutting down variation module "%s"...' % variationModuleName)
log.info('Shutting down variation module "%s"...' % variationModuleName)
try:
variationModule['shutdown'](options=variationModuleOptions,
mode='recording')
except Exception:
log.msg('Variation module "%s" shutdown FAILED: %s' % (variationModuleName, sys.exc_info()[1]))
log.error('Variation module "%s" shutdown FAILED: %s' % (variationModuleName, sys.exc_info()[1]))

else:
log.msg('Variation module "%s" shutdown OK' % variationModuleName)
log.info('Variation module "%s" shutdown OK' % variationModuleName)

log.msg("""PCap statistics:
log.info("""PCap statistics:
packets snooped: %s
packets dropped: %s
packets dropped: by interface %s""" % pcapObj.stats())
log.msg("""SNMP statistics:
log.info("""SNMP statistics:
%s""" % ' '.join(['%s: %s\r\n' % kv for kv in stats.items()]))

if exc_info:
for line in traceback.format_exception(*exc_info):
log.msg(line.replace('\n', ';'))
log.error(line.replace('\n', ';'))

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