mirror of
https://github.com/JakeHillion/object-introspection.git
synced 2024-09-19 19:19:05 +01:00
129 lines
3.3 KiB
C++
129 lines
3.3 KiB
C++
/*
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* Copyright (c) Meta Platforms, Inc. and affiliates.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "oi/Descs.h"
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#include <glog/logging.h>
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#include <algorithm>
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#include <boost/scope_exit.hpp>
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#include <charconv>
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#include <iostream>
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#include <utility>
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extern "C" {
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#include <drgn.h>
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#include <sys/user.h>
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}
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std::ostream& operator<<(std::ostream& os, const FuncDesc::Range& r) {
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return os << (void*)r.start << ':' << (void*)r.end;
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}
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/*
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* Given a register set return the address where the supplied argument
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* position can be found at the given pc (what about if we don't have this
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* location?).
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*/
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std::optional<uintptr_t> FuncDesc::Arg::findAddress(
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struct user_regs_struct* regs, uintptr_t pc) const {
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auto prevRip = std::exchange(regs->rip, pc);
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BOOST_SCOPE_EXIT_ALL(&) {
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regs->rip = prevRip;
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};
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struct drgn_object object {};
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BOOST_SCOPE_EXIT_ALL(&) {
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drgn_object_deinit(&object);
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};
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if (auto* err = drgn_object_locate(&locator, regs, &object)) {
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LOG(ERROR) << "Error while finding address of argument: " << err->message;
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drgn_error_destroy(err);
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return std::nullopt;
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}
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return object.address;
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}
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std::optional<uint8_t> FuncDesc::getArgumentIndex(const std::string& arg,
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bool validateIndex) const {
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if (arg == "retval") {
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return std::nullopt;
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}
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if (arg == "this") {
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if (!isMethod) {
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LOG(ERROR) << "Function " << symName << " has no 'this' parameter";
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return std::nullopt;
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}
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return 0;
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}
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//
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// Extract arg's number
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auto it = arg.find_first_of("0123456789");
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if (it == std::string::npos) {
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LOG(ERROR) << "Invalid argument: " << arg;
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return std::nullopt;
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}
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const auto* argIdxBegin = arg.data() + it;
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const auto* argIdxEnd = arg.data() + arg.size();
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uint8_t argIdx = 0;
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if (auto res = std::from_chars(argIdxBegin, argIdxEnd, argIdx);
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res.ec != std::errc{}) {
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LOG(ERROR) << "Failed to convert " << arg
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<< " digits: " << strerror((int)res.ec);
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return std::nullopt;
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}
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// Check and offset for methods
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if (validateIndex && argIdx >= numArgs()) {
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LOG(ERROR) << "Argument index " << (int)argIdx
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<< " too large. Args count: " << numArgs();
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return std::nullopt;
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}
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if (isMethod) {
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argIdx += 1;
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}
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return argIdx;
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}
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std::shared_ptr<FuncDesc::TargetObject> FuncDesc::getArgument(
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const std::string& arg) {
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std::shared_ptr<FuncDesc::TargetObject> outArg;
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if (arg == "retval") {
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outArg = retval;
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} else {
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auto argIdx = getArgumentIndex(arg);
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if (!argIdx.has_value()) {
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return nullptr;
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}
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outArg = arguments[*argIdx];
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}
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if (!outArg || !outArg->valid) {
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LOG(ERROR) << "Argument " << arg << " for " << symName << " is invalid";
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return nullptr;
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}
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return outArg;
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}
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