1 #!/usr/bin/env bcc-lua 2 --[[ 3 Copyright 2016 Marek Vavrusa <mvavrusa@cloudflare.com> 4 5 Licensed under the Apache License, Version 2.0 (the "License"); 6 you may not use this file except in compliance with the License. 7 You may obtain a copy of the License at 8 9 http://www.apache.org/licenses/LICENSE-2.0 10 11 Unless required by applicable law or agreed to in writing, software 12 distributed under the License is distributed on an "AS IS" BASIS, 13 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 See the License for the specific language governing permissions and 15 limitations under the License. 16 ]] 17 -- Trace readline() call from all bash instances (print bash commands from all running shells). 18 -- This is rough equivallent to `bashreadline` 19 -- Source: http://www.brendangregg.com/blog/2016-02-08/linux-ebpf-bcc-uprobes.html 20 local ffi = require('ffi') 21 local bpf = require('bpf') 22 local S = require('syscall') 23 -- Kernel-space part of the program 24 local probe = bpf.uprobe('/bin/bash:readline', function (ptregs) 25 local line = ffi.new('char [40]') -- Create a 40 byte buffer on stack 26 ffi.copy(line, ffi.cast('char *', ptregs.ax)) -- Cast `ax` to string pointer and copy to buffer 27 print('%s\n', line) -- Print to trace_pipe 28 end, true, -1, 0) 29 -- User-space part of the program 30 local ok, err = pcall(function() 31 local log = bpf.tracelog() 32 print(' TASK-PID CPU# TIMESTAMP FUNCTION') 33 print(' | | | | |') 34 while true do 35 print(log:read()) 36 end 37 end) 38
