#! /usr/bin/python3
# @lint-avoid-python-3-compatibility-imports
from __future__ import print_function
import argparse
import os
import platform
import re
import signal
import sys
from bcc import BPF
from datetime import datetime
from time import strftime
#
# exitsnoop Trace all process termination (exit, fatal signal)
# For Linux, uses BCC, eBPF. Embedded C.
#
# USAGE: exitsnoop [-h] [-x] [-t] [--utc] [--label[=LABEL]] [-p PID]
#
_examples = """examples:
exitsnoop # trace all process termination
exitsnoop -x # trace only fails, exclude exit(0)
exitsnoop -t # include timestamps (local time)
exitsnoop --utc # include timestamps (UTC)
exitsnoop -p 181 # only trace PID 181
exitsnoop --label=exit # label each output line with 'exit'
exitsnoop --per-thread # trace per thread termination
"""
"""
Exit status (from <include/sysexits.h>):
0 EX_OK Success
2 argparse error
70 EX_SOFTWARE syntax error detected by compiler, or
verifier error from kernel
77 EX_NOPERM Need sudo (CAP_SYS_ADMIN) for BPF() system call
The template for this script was Brendan Gregg's execsnoop
https://github.com/iovisor/bcc/blob/master/tools/execsnoop.py
More information about this script is in bcc/tools/exitsnoop_example.txt
Copyright 2016 Netflix, Inc.
Copyright 2019 Instana, Inc.
Licensed under the Apache License, Version 2.0 (the "License")
07-Feb-2016 Brendan Gregg (Netflix) Created execsnoop
04-May-2019 Arturo Martin-de-Nicolas (Instana) Created exitsnoop
13-May-2019 Jeroen Soeters (Instana) Refactor to import as module
"""
def _getParser():
parser = argparse.ArgumentParser(
description="Trace all process termination (exit, fatal signal)",
formatter_class=argparse.RawDescriptionHelpFormatter,
epilog=_examples)
a=parser.add_argument
a("-t", "--timestamp", action="store_true", help="include timestamp (local time default)")
a("--utc", action="store_true", help="include timestamp in UTC (-t implied)")
a("-p", "--pid", help="trace this PID only")
a("--label", help="label each line")
a("-x", "--failed", action="store_true", help="trace only fails, exclude exit(0)")
a("--per-thread", action="store_true", help="trace per thread termination")
# print the embedded C program and exit, for debugging
a("--ebpf", action="store_true", help=argparse.SUPPRESS)
# RHEL 7.6 keeps task->start_time as struct timespec, convert to u64 nanoseconds
a("--timespec", action="store_true", help=argparse.SUPPRESS)
return parser.parse_args
class Global():
parse_args = _getParser()
args = None
argv = None
SIGNUM_TO_SIGNAME = dict((v, re.sub("^SIG", "", k))
for k,v in signal.__dict__.items() if re.match("^SIG[A-Z]+$", k))
def _embedded_c(args):
"""Generate C program for sched_process_exit tracepoint in kernel/exit.c."""
c = """
EBPF_COMMENT
#include <linux/sched.h>
struct data_t {
u64 start_time;
u64 exit_time;
u32 pid;
u32 tid;
u32 ppid;
int exit_code;
u32 sig_info;
char task[TASK_COMM_LEN];
};
BPF_PERF_OUTPUT(events);
TRACEPOINT_PROBE(sched, sched_process_exit)
{
struct task_struct *task = (typeof(task))bpf_get_current_task();
if (FILTER_PID || FILTER_EXIT_CODE) { return 0; }
struct data_t data = {};
data.start_time = PROCESS_START_TIME_NS,
data.exit_time = bpf_ktime_get_ns(),
data.pid = task->tgid,
data.tid = task->pid,
data.ppid = task->real_parent->tgid,
data.exit_code = task->exit_code >> 8,
data.sig_info = task->exit_code & 0xFF,
bpf_get_current_comm(&data.task, sizeof(data.task));
events.perf_submit(args, &data, sizeof(data));
return 0;
}
"""
if Global.args.pid:
if Global.args.per_thread:
filter_pid = "task->tgid != %s" % Global.args.pid
else:
filter_pid = "!(task->tgid == %s && task->pid == task->tgid)" % Global.args.pid
else:
filter_pid = '0' if Global.args.per_thread else 'task->pid != task->tgid'
code_substitutions = [
('EBPF_COMMENT', '' if not Global.args.ebpf else _ebpf_comment()),
('FILTER_PID', filter_pid),
('FILTER_EXIT_CODE', '0' if not Global.args.failed else 'task->exit_code == 0'),
('PROCESS_START_TIME_NS', 'task->start_time' if not Global.args.timespec else
'(task->start_time.tv_sec * 1000000000L) + task->start_time.tv_nsec'),
]
for old,new in code_substitutions:
c = c.replace(old, new)
return c
def _ebpf_comment():
"""Return a C-style comment with information about the generated code."""
comment=('Created by %s at %s:\n\t%s' %
(sys.argv[0], strftime("%Y-%m-%d %H:%M:%S %Z"), _embedded_c.__doc__))
args = str(vars(Global.args)).replace('{','{\n\t').replace(', ',',\n\t').replace('}',',\n }\n\n')
return ("\n /*" + ("\n %s\n\n ARGV = %s\n\n ARGS = %s/" %
(comment, ' '.join(Global.argv), args))
.replace('\n','\n\t*').replace('\t',' '))
def _print_header():
if Global.args.timestamp:
title = 'TIME-' + ('UTC' if Global.args.utc else strftime("%Z"))
print("%-13s" % title, end="")
if Global.args.label is not None:
print("%-6s" % "LABEL", end="")
print("%-16s %-7s %-7s %-7s %-7s %-10s" %
("PCOMM", "PID", "PPID", "TID", "AGE(s)", "EXIT_CODE"))
buffer = None
def _print_event(cpu, data, size): # callback
"""Print the exit event."""
global buffer
e = buffer["events"].event(data)
if Global.args.timestamp:
now = datetime.utcnow() if Global.args.utc else datetime.now()
print("%-13s" % (now.strftime("%H:%M:%S.%f")[:-3]), end="")
if Global.args.label is not None:
label = Global.args.label if len(Global.args.label) else 'exit'
print("%-6s" % label, end="")
age = (e.exit_time - e.start_time) / 1e9
print("%-16s %-7d %-7d %-7d %-7.2f " %
(e.task.decode(), e.pid, e.ppid, e.tid, age), end="")
if e.sig_info == 0:
print("0" if e.exit_code == 0 else "code %d" % e.exit_code)
else:
sig = e.sig_info & 0x7F
if sig:
print("signal %d (%s)" % (sig, signum_to_signame(sig)), end="")
if e.sig_info & 0x80:
print(", core dumped ", end="")
print()
# =============================
# Module: These functions are available for import
# =============================
def initialize(arg_list = sys.argv[1:]):
"""Trace all process termination.
arg_list - list of args, if omitted then uses command line args
arg_list is passed to argparse.ArgumentParser.parse_args()
For example, if arg_list = [ '-x', '-t' ]
args.failed == True
args.timestamp == True
Returns a tuple (return_code, result)
0 = Ok, result is the return value from BPF()
1 = args.ebpf is requested, result is the generated C code
os.EX_NOPERM: need CAP_SYS_ADMIN, result is error message
os.EX_SOFTWARE: internal software error, result is error message
"""
Global.argv = arg_list
Global.args = Global.parse_args(arg_list)
if Global.args.utc and not Global.args.timestamp:
Global.args.timestamp = True
if not Global.args.ebpf and os.geteuid() != 0:
return (os.EX_NOPERM, "Need sudo (CAP_SYS_ADMIN) for BPF() system call")
if re.match(r'^3.10..*el7.*$', platform.release()): # Centos/Red Hat
Global.args.timespec = True
for _ in range(2):
c = _embedded_c(Global.args)
if Global.args.ebpf:
return (1, c)
try:
return (os.EX_OK, BPF(text=c))
except Exception as e:
error = format(e)
if (not Global.args.timespec
and error.find('struct timespec')
and error.find('start_time')):
print('This kernel keeps task->start_time in a struct timespec.\n' +
'Retrying with --timespec')
Global.args.timespec = True
continue
return (os.EX_SOFTWARE, "BPF error: " + error)
except:
return (os.EX_SOFTWARE, "Unexpected error: {0}".format(sys.exc_info()[0]))
def snoop(bpf, event_handler):
"""Call event_handler for process termination events.
bpf - result returned by successful initialize()
event_handler - callback function to handle termination event
args.pid - Return after event_handler is called, only monitoring this pid
"""
bpf["events"].open_perf_buffer(event_handler)
while True:
bpf.perf_buffer_poll()
if Global.args.pid:
return
def signum_to_signame(signum):
"""Return the name of the signal corresponding to signum."""
return Global.SIGNUM_TO_SIGNAME.get(signum, "unknown")
# =============================
# Script: invoked as a script
# =============================
def main():
global buffer
try:
rc, buffer = initialize()
if rc:
print(buffer)
sys.exit(0 if Global.args.ebpf else rc)
_print_header()
snoop(buffer, _print_event)
except KeyboardInterrupt:
print()
sys.exit()
return 0
if __name__ == '__main__':
main()
Mini Shell