1--[[ 2Copyright 2016 GitHub, Inc 3 4Licensed under the Apache License, Version 2.0 (the "License"); 5you may not use this file except in compliance with the License. 6You may obtain a copy of the License at 7 8http://www.apache.org/licenses/LICENSE-2.0 9 10Unless required by applicable law or agreed to in writing, software 11distributed under the License is distributed on an "AS IS" BASIS, 12WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13See the License for the specific language governing permissions and 14limitations under the License. 15]] 16local ffi = require("ffi") 17local libbcc = require("bcc.libbcc") 18local Usdt = class("USDT") 19 20Usdt.static.open_contexts = {} 21 22function Usdt.static.cleanup() 23 for _, context in ipairs(Usdt.static.open_contexts) do 24 context:_cleanup() 25 end 26end 27 28function Usdt:initialize(args) 29 assert(args.pid or args.path) 30 31 if args.pid then 32 self.pid = args.pid 33 self.context = libbcc.bcc_usdt_new_frompid(args.pid) 34 elseif args.path then 35 self.path = args.path 36 self.context = libbcc.bcc_usdt_new_frompath(args.path) 37 end 38 39 assert(self.context ~= nil, "failed to create USDT context") 40 table.insert(Usdt.open_contexts, self) 41end 42 43function Usdt:enable_probe(args) 44 assert(args.probe and args.fn_name) 45 assert(libbcc.bcc_usdt_enable_probe( 46 self.context, args.probe, args.fn_name) == 0) 47end 48 49function Usdt:_cleanup() 50 libbcc.bcc_usdt_close(self.context) 51 self.context = nil 52end 53 54function Usdt:_get_text() 55 local argc = libbcc.bcc_usdt_genargs(self.context) 56 assert(argc ~= nil) 57 return ffi.string(argc) 58end 59 60function Usdt:_attach_uprobes(bpf) 61 local uprobes = {} 62 local cb = ffi.cast("bcc_usdt_uprobe_cb", 63 function(binpath, fn_name, addr, pid) 64 table.insert(uprobes, {name=ffi.string(binpath), 65 addr=addr, fn_name=ffi.string(fn_name), pid=pid}) 66 end) 67 68 libbcc.bcc_usdt_foreach_uprobe(self.context, cb) 69 cb:free() 70 71 for _, args in ipairs(uprobes) do 72 bpf:attach_uprobe(args) 73 end 74end 75 76return Usdt 77