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Copy pathkillsnoop.py
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executable file
·148 lines (125 loc) · 3.53 KB
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#!/usr/bin/python
# @lint-avoid-python-3-compatibility-imports
#
# killsnoop Trace signals issued by the kill() syscall.
# For Linux, uses BCC, eBPF. Embedded C.
#
# USAGE: killsnoop [-h] [-x] [-p PID]
#
# Copyright (c) 2015 Brendan Gregg.
# Licensed under the Apache License, Version 2.0 (the "License")
#
# 20-Sep-2015 Brendan Gregg Created this.
# 19-Feb-2016 Allan McAleavy migrated to BPF_PERF_OUTPUT
from __future__ import print_function
from bcc import BPF
from bcc.utils import ArgString, printb
import argparse
from time import strftime
import ctypes as ct
# arguments
examples = """examples:
./killsnoop # trace all kill() signals
./killsnoop -x # only show failed kills
./killsnoop -p 181 # only trace PID 181
"""
parser = argparse.ArgumentParser(
description="Trace signals issued by the kill() syscall",
formatter_class=argparse.RawDescriptionHelpFormatter,
epilog=examples)
parser.add_argument("-x", "--failed", action="store_true",
help="only show failed kill syscalls")
parser.add_argument("-p", "--pid",
help="trace this PID only")
parser.add_argument("--ebpf", action="store_true",
help=argparse.SUPPRESS)
args = parser.parse_args()
debug = 0
# define BPF program
bpf_text = """
#include <uapi/linux/ptrace.h>
#include <linux/sched.h>
struct val_t {
u64 pid;
int sig;
int tpid;
char comm[TASK_COMM_LEN];
};
struct data_t {
u64 pid;
int tpid;
int sig;
int ret;
char comm[TASK_COMM_LEN];
};
BPF_HASH(infotmp, u32, struct val_t);
BPF_PERF_OUTPUT(events);
int syscall__kill(struct pt_regs *ctx, int tpid, int sig)
{
u32 pid = bpf_get_current_pid_tgid();
FILTER
struct val_t val = {.pid = pid};
if (bpf_get_current_comm(&val.comm, sizeof(val.comm)) == 0) {
val.tpid = tpid;
val.sig = sig;
infotmp.update(&pid, &val);
}
return 0;
};
int do_ret_sys_kill(struct pt_regs *ctx)
{
struct data_t data = {};
struct val_t *valp;
u32 pid = bpf_get_current_pid_tgid();
valp = infotmp.lookup(&pid);
if (valp == 0) {
// missed entry
return 0;
}
bpf_probe_read(&data.comm, sizeof(data.comm), valp->comm);
data.pid = pid;
data.tpid = valp->tpid;
data.ret = PT_REGS_RC(ctx);
data.sig = valp->sig;
events.perf_submit(ctx, &data, sizeof(data));
infotmp.delete(&pid);
return 0;
}
"""
if args.pid:
bpf_text = bpf_text.replace('FILTER',
'if (pid != %s) { return 0; }' % args.pid)
else:
bpf_text = bpf_text.replace('FILTER', '')
if debug or args.ebpf:
print(bpf_text)
if args.ebpf:
exit()
# initialize BPF
b = BPF(text=bpf_text)
kill_fnname = b.get_syscall_fnname("kill")
b.attach_kprobe(event=kill_fnname, fn_name="syscall__kill")
b.attach_kretprobe(event=kill_fnname, fn_name="do_ret_sys_kill")
TASK_COMM_LEN = 16 # linux/sched.h
class Data(ct.Structure):
_fields_ = [
("pid", ct.c_ulonglong),
("tpid", ct.c_int),
("sig", ct.c_int),
("ret", ct.c_int),
("comm", ct.c_char * TASK_COMM_LEN)
]
# header
print("%-9s %-6s %-16s %-4s %-6s %s" % (
"TIME", "PID", "COMM", "SIG", "TPID", "RESULT"))
# process event
def print_event(cpu, data, size):
event = ct.cast(data, ct.POINTER(Data)).contents
if (args.failed and (event.ret >= 0)):
return
3578
printb(b"%-9s %-6d %-16s %-4d %-6d %d" % (strftime("%H:%M:%S"),
event.pid, event.comm, event.sig, event.tpid, event.ret))
# loop with callback to print_event
b["events"].open_perf_buffer(print_event)
while 1:
b.perf_buffer_poll()