| #!/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 |
| 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 kprobe__sys_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 kretprobe__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) |
| |
| 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 |
| |
| print("%-9s %-6d %-16s %-4d %-6d %d" % (strftime("%H:%M:%S"), |
| event.pid, event.comm.decode(), event.sig, event.tpid, event.ret)) |
| |
| # loop with callback to print_event |
| b["events"].open_perf_buffer(print_event) |
| while 1: |
| b.kprobe_poll() |