Colin Cross | 0965c02 | 2016-04-26 16:51:32 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2016 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | #ifndef LIBMEMUNREACHABLE_SCOPED_SIGNAL_HANDLER_H_ |
| 18 | #define LIBMEMUNREACHABLE_SCOPED_SIGNAL_HANDLER_H_ |
| 19 | |
| 20 | #include <errno.h> |
| 21 | #include <signal.h> |
| 22 | |
| 23 | #include <functional> |
| 24 | |
| 25 | #include "android-base/macros.h" |
| 26 | |
| 27 | #include "log.h" |
| 28 | |
| 29 | class ScopedSignalHandler { |
| 30 | public: |
| 31 | using Fn = std::function<void(ScopedSignalHandler&, int, siginfo_t*, void*)>; |
| 32 | |
Chih-Hung Hsieh | 034c475 | 2016-07-12 13:50:44 -0700 | [diff] [blame] | 33 | explicit ScopedSignalHandler(Allocator<Fn> allocator) : allocator_(allocator), signal_(-1) {} |
Colin Cross | 0965c02 | 2016-04-26 16:51:32 -0700 | [diff] [blame] | 34 | ~ScopedSignalHandler() { |
| 35 | reset(); |
| 36 | } |
| 37 | |
| 38 | template <class F> |
| 39 | void install(int signal, F&& f) { |
| 40 | LOG_ALWAYS_FATAL_IF(signal_ != -1, "ScopedSignalHandler already installed"); |
| 41 | |
| 42 | handler_ = SignalFn(std::allocator_arg, allocator_, |
| 43 | [=](int signal, siginfo_t* si, void* uctx) { |
| 44 | f(*this, signal, si, uctx); |
| 45 | }); |
| 46 | |
| 47 | struct sigaction act{}; |
| 48 | act.sa_sigaction = [](int signal, siginfo_t* si, void* uctx) { |
| 49 | handler_(signal, si, uctx); |
| 50 | }; |
| 51 | act.sa_flags = SA_SIGINFO; |
| 52 | |
| 53 | int ret = sigaction(signal, &act, &old_act_); |
| 54 | if (ret < 0) { |
| 55 | LOG_ALWAYS_FATAL("failed to install segfault handler: %s", strerror(errno)); |
| 56 | } |
| 57 | |
| 58 | signal_ = signal; |
| 59 | } |
| 60 | |
| 61 | void reset() { |
| 62 | if (signal_ != -1) { |
| 63 | int ret = sigaction(signal_, &old_act_, NULL); |
| 64 | if (ret < 0) { |
| 65 | ALOGE("failed to uninstall segfault handler"); |
| 66 | } |
| 67 | handler_ = SignalFn{}; |
| 68 | signal_ = -1; |
| 69 | } |
| 70 | } |
| 71 | |
| 72 | |
| 73 | private: |
| 74 | using SignalFn = std::function<void(int, siginfo_t*, void*)>; |
| 75 | DISALLOW_COPY_AND_ASSIGN(ScopedSignalHandler); |
| 76 | Allocator<Fn> allocator_; |
| 77 | int signal_; |
| 78 | struct sigaction old_act_; |
| 79 | // TODO(ccross): to support multiple ScopedSignalHandlers handler_ would need |
| 80 | // to be a static map of signals to handlers, but allocated with Allocator. |
| 81 | static SignalFn handler_; |
| 82 | }; |
| 83 | |
| 84 | #endif // LIBMEMUNREACHABLE_SCOPED_SIGNAL_HANDLER_H_ |