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Copy pathstatsnoop.py
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executable file
·181 lines (153 loc) · 4.75 KB
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#!/usr/bin/python
# @lint-avoid-python-3-compatibility-imports
#
# statsnoop Trace stat() syscalls.
# For Linux, uses BCC, eBPF. Embedded C.
#
# USAGE: statsnoop [-h] [-t] [-x] [-p PID]
#
# Copyright 2016 Netflix, Inc.
# Licensed under the Apache License, Version 2.0 (the "License")
#
# 08-Feb-2016 Brendan Gregg Created this.
# 17-Feb-2016 Allan McAleavy updated for BPF_PERF_OUTPUT
from __future__ import print_function
from bcc import BPF
import argparse
import ctypes as ct
# arguments
examples = """examples:
./statsnoop # trace all stat() syscalls
./statsnoop -t # include timestamps
./statsnoop -x # only show failed stats
./statsnoop -p 181 # only trace PID 181
"""
parser = argparse.ArgumentParser(
description="Trace stat() syscalls",
formatter_class=argparse.RawDescriptionHelpFormatter,
epilog=examples)
parser.add_argument("-t", "--timestamp", action="store_true",
help="include timestamp on output")
parser.add_argument("-x", "--failed", action="store_true",
help="only show failed stats")
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 <uapi/linux/limits.h>
#include <linux/sched.h>
struct val_t {
const char *fname;
};
struct data_t {
u32 pid;
u64 ts_ns;
int ret;
char comm[TASK_COMM_LEN];
char fname[NAME_MAX];
};
BPF_HASH(args_filename, u32, const char *);
BPF_HASH(infotmp, u32, struct val_t);
BPF_PERF_OUTPUT(events);
int syscall__entry(struct pt_regs *ctx, const char __user *filename)
{
struct val_t val = {};
u32 pid = bpf_get_current_pid_tgid();
FILTER
val.fname = filename;
infotmp.update(&pid, &val);
return 0;
};
int trace_return(struct pt_regs *ctx)
{
u32 pid = bpf_get_current_pid_tgid();
struct val_t *valp;
valp = infotmp.lookup(&pid);
if (valp == 0) {
// missed entry
return 0;
}
struct data_t data = {.pid = pid};
bpf_probe_read(&data.fname, sizeof(data.fname), (void *)valp->fname);
bpf_get_current_comm(&data.comm, sizeof(data.comm));
data.ts_ns = bpf_ktime_get_ns();
data.ret = PT_REGS_RC(ctx);
events.perf_submit(ctx, &data, sizeof(data));
infotmp.delete(&pid);
args_filename.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)
# for POSIX compliance, all architectures implement these
# system calls but the name of the actual entry point may
# be different for which we must check if the entry points
# actually exist before attaching the probes
syscall_fnname = b.get_syscall_fnname("stat")
if BPF.ksymname(syscall_fnname) != -1:
b.attach_kprobe(event=syscall_fnname, fn_name="syscall__entry")
b.attach_kretprobe(event=syscall_fnname, fn_name="trace_return")
syscall_fnname = b.get_syscall_fnname("statfs")
if BPF.ksymname(syscall_fnname) != -1:
b.attach_kprobe(event=syscall_fnname, fn_name="syscall__entry")
b.attach_kretprobe(event=syscall_fnname, fn_name="trace_return")
syscall_fnname = b.get_syscall_fnname("newstat")
if BPF.ksymname(syscall_fnname) != -1:
b.attach_kprobe(event=syscall_fnname, fn_name="syscall__entry")
b.attach_kretprobe(event=syscall_fnname, fn_name="trace_return")
TASK_COMM_LEN = 16 # linux/sched.h
NAME_MAX = 255 # linux/limits.h
class Data(ct.Structure):
_fields_ = [
("pid", ct.c_ulonglong),
("ts_ns", ct.c_ulonglong),
("ret", ct.c_int),
("comm", ct.c_char * TASK_COMM_LEN),
("fname", ct.c_char * NAME_MAX)
]
start_ts = 0
prev_ts = 0
delta = 0
# header
if args.timestamp:
print("%-14s" % ("TIME(s)"), end="")
print("%-6s %-16s %4s %3s %s" % ("PID", "COMM", "FD", "ERR", "PATH"))
# process event
def print_event(cpu, data, size):
event = ct.cast(data, ct.POINTER(Data)).contents
global start_ts
global prev_ts
global delta
global cont
# split return value into FD and errno columns
if event.ret >= 0:
fd_s = event.ret
err = 0
else:
fd_s = -1
err = - event.ret
if start_ts == 0:
start_ts = event.ts_ns
if args.timestamp:
print("%-14.9f" % (float(event.ts_ns - start_ts) / 1000000000), end="")
print("%-6d %-16s %4d %3d %s" % (event.pid, event.comm.decode(),
fd_s, err, event.fname.decode()))
# loop with callback to print_event
b["events"].open_perf_buffer(print_event, page_cnt=64)
while 1:
b.perf_buffer_poll()