1#!/usr/bin/python 2# @lint-avoid-python-3-compatibility-imports 3# 4# filelife Trace the lifespan of short-lived files. 5# For Linux, uses BCC, eBPF. Embedded C. 6# 7# This traces the creation and deletion of files, providing information 8# on who deleted the file, the file age, and the file name. The intent is to 9# provide information on short-lived files, for debugging or performance 10# analysis. 11# 12# USAGE: filelife [-h] [-p PID] 13# 14# Copyright 2016 Netflix, Inc. 15# Licensed under the Apache License, Version 2.0 (the "License") 16# 17# 08-Feb-2015 Brendan Gregg Created this. 18# 17-Feb-2016 Allan McAleavy updated for BPF_PERF_OUTPUT 19 20from __future__ import print_function 21from bcc import BPF 22import argparse 23from time import strftime 24import ctypes as ct 25 26# arguments 27examples = """examples: 28 ./filelife # trace all stat() syscalls 29 ./filelife -p 181 # only trace PID 181 30""" 31parser = argparse.ArgumentParser( 32 description="Trace stat() syscalls", 33 formatter_class=argparse.RawDescriptionHelpFormatter, 34 epilog=examples) 35parser.add_argument("-p", "--pid", 36 help="trace this PID only") 37parser.add_argument("--ebpf", action="store_true", 38 help=argparse.SUPPRESS) 39args = parser.parse_args() 40debug = 0 41 42# define BPF program 43bpf_text = """ 44#include <uapi/linux/ptrace.h> 45#include <linux/fs.h> 46#include <linux/sched.h> 47 48struct data_t { 49 u32 pid; 50 u64 delta; 51 char comm[TASK_COMM_LEN]; 52 char fname[DNAME_INLINE_LEN]; 53}; 54 55BPF_HASH(birth, struct dentry *); 56BPF_PERF_OUTPUT(events); 57 58// trace file creation time 59int trace_create(struct pt_regs *ctx, struct inode *dir, struct dentry *dentry) 60{ 61 u32 pid = bpf_get_current_pid_tgid(); 62 FILTER 63 64 u64 ts = bpf_ktime_get_ns(); 65 birth.update(&dentry, &ts); 66 67 return 0; 68}; 69 70// trace file deletion and output details 71int trace_unlink(struct pt_regs *ctx, struct inode *dir, struct dentry *dentry) 72{ 73 struct data_t data = {}; 74 u32 pid = bpf_get_current_pid_tgid(); 75 76 FILTER 77 78 u64 *tsp, delta; 79 tsp = birth.lookup(&dentry); 80 if (tsp == 0) { 81 return 0; // missed create 82 } 83 84 delta = (bpf_ktime_get_ns() - *tsp) / 1000000; 85 birth.delete(&dentry); 86 87 struct qstr d_name = dentry->d_name; 88 if (d_name.len == 0) 89 return 0; 90 91 if (bpf_get_current_comm(&data.comm, sizeof(data.comm)) == 0) { 92 data.pid = pid; 93 data.delta = delta; 94 bpf_probe_read(&data.fname, sizeof(data.fname), d_name.name); 95 } 96 97 events.perf_submit(ctx, &data, sizeof(data)); 98 99 return 0; 100} 101""" 102 103TASK_COMM_LEN = 16 # linux/sched.h 104DNAME_INLINE_LEN = 255 # linux/dcache.h 105 106class Data(ct.Structure): 107 _fields_ = [ 108 ("pid", ct.c_uint), 109 ("delta", ct.c_ulonglong), 110 ("comm", ct.c_char * TASK_COMM_LEN), 111 ("fname", ct.c_char * DNAME_INLINE_LEN) 112 ] 113 114if args.pid: 115 bpf_text = bpf_text.replace('FILTER', 116 'if (pid != %s) { return 0; }' % args.pid) 117else: 118 bpf_text = bpf_text.replace('FILTER', '') 119if debug or args.ebpf: 120 print(bpf_text) 121 if args.ebpf: 122 exit() 123 124# initialize BPF 125b = BPF(text=bpf_text) 126b.attach_kprobe(event="vfs_create", fn_name="trace_create") 127# newer kernels (say, 4.8) may don't fire vfs_create, so record (or overwrite) 128# the timestamp in security_inode_create(): 129b.attach_kprobe(event="security_inode_create", fn_name="trace_create") 130b.attach_kprobe(event="vfs_unlink", fn_name="trace_unlink") 131 132# header 133print("%-8s %-6s %-16s %-7s %s" % ("TIME", "PID", "COMM", "AGE(s)", "FILE")) 134 135# process event 136def print_event(cpu, data, size): 137 event = ct.cast(data, ct.POINTER(Data)).contents 138 print("%-8s %-6d %-16s %-7.2f %s" % (strftime("%H:%M:%S"), event.pid, 139 event.comm.decode('utf-8', 'replace'), float(event.delta) / 1000, 140 event.fname.decode('utf-8', 'replace'))) 141 142b["events"].open_perf_buffer(print_event) 143while 1: 144 b.perf_buffer_poll() 145