You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
66 lines
2.5 KiB
66 lines
2.5 KiB
4 months ago
|
#!/usr/bin/env bcc-lua
|
||
|
|
--[[
|
||
|
|
Copyright 2016 Marek Vavrusa <mvavrusa@cloudflare.com>
|
||
|
|
|
||
|
|
Licensed under the Apache License, Version 2.0 (the "License");
|
||
|
|
you may not use this file except in compliance with the License.
|
||
|
|
You may obtain a copy of the License at
|
||
|
|
|
||
|
|
http://www.apache.org/licenses/LICENSE-2.0
|
||
|
|
|
||
|
|
Unless required by applicable law or agreed to in writing, software
|
||
|
|
distributed under the License is distributed on an "AS IS" BASIS,
|
||
|
|
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||
|
|
See the License for the specific language governing permissions and
|
||
|
|
limitations under the License.
|
||
|
|
]]
|
||
|
|
-- Trace operations on keys matching given pattern in KyotoTycoon daemon.
|
||
|
|
-- This can show you if certain keys were modified or read during the lifetime
|
||
|
|
-- even if KT doesn't support this. It also shows how to attach to C++ mangled symbols.
|
||
|
|
local ffi = require('ffi')
|
||
|
|
local bpf = require('bpf')
|
||
|
|
local S = require('syscall')
|
||
|
|
local function help(err)
|
||
|
|
print(string.format('%s [get|set] [key]', arg[0]))
|
||
|
|
if err then print('error: '..err) end
|
||
|
|
os.exit(1)
|
||
|
|
end
|
||
|
|
-- Accept the same format as ktremotemgr for clarity: <get|set> <key>
|
||
|
|
local writeable, watch_key, klen = 'any', arg[2] or '*', 80
|
||
|
|
if arg[1] == 'get' then writeable = 0
|
||
|
|
elseif arg[1] == 'set' then writeable = 1
|
||
|
|
elseif arg[1] == '-h' or arg[1] == '--help' then help()
|
||
|
|
elseif arg[1] and arg[1] ~= 'any' then
|
||
|
|
help(string.format('bad cmd: "%s"', arg[1]))
|
||
|
|
end
|
||
|
|
if watch_key ~= '*' then klen = #watch_key end
|
||
|
|
|
||
|
|
-- Find a good entrypoint that has both key and differentiates read/write in KT
|
||
|
|
-- That is going to serve as an attachment point for BPF program
|
||
|
|
-- ABI: bool accept(void *this, const char* kbuf, size_t ksiz, Visitor* visitor, bool writable)
|
||
|
|
local key_type = string.format('char [%d]', klen)
|
||
|
|
local probe = bpf.uprobe('/usr/local/bin/ktserver:kyotocabinet::StashDB::accept',
|
||
|
|
function (ptregs)
|
||
|
|
-- Watch either get/set or both
|
||
|
|
if writeable ~= 'any' then
|
||
|
|
if ptregs.parm5 ~= writeable then return end
|
||
|
|
end
|
||
|
|
local line = ffi.new(key_type)
|
||
|
|
ffi.copy(line, ffi.cast('char *', ptregs.parm2))
|
||
|
|
-- Check if we're looking for specific key
|
||
|
|
if watch_key ~= '*' then
|
||
|
|
if ptregs.parm3 ~= klen then return false end
|
||
|
|
if line ~= watch_key then return false end
|
||
|
|
end
|
||
|
|
print('%s write:%d\n', line, ptregs.parm5)
|
||
|
|
end, false, -1, 0)
|
||
|
|
-- User-space part of the program
|
||
|
|
local ok, err = pcall(function()
|
||
|
|
local log = bpf.tracelog()
|
||
|
|
print(' TASK-PID CPU# TIMESTAMP FUNCTION')
|
||
|
|
print(' | | | | |')
|
||
|
|
while true do
|
||
|
|
print(log:read())
|
||
|
|
end
|
||
|
|
end)
|