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