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80 lines
3.5 KiB
C++
80 lines
3.5 KiB
C++
// SPDX-License-Identifier: MPL-2.0
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// Copyright © 2020 Skyline Team and Contributors (https://github.com/skyline-emu/)
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#pragma once
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#include <common.h>
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namespace skyline::signal {
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/**
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* @brief The structure of a stack frame entry in the ARMv8 ABI
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*/
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struct StackFrame {
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StackFrame *next;
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void *lr;
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};
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/**
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* @brief An exception object that is designed specifically to hold Linux signals
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* @note This doesn't inherit std::exception as it shouldn't be caught as such
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* @note Refer to the manpage siginfo(3) for information on members
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*/
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class SignalException {
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public:
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int signal{};
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void* pc{};
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void *fault{};
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std::vector<void*> frames; //!< A vector of all stack frame entries prior to the signal occuring
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inline std::string what() const {
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if (!fault)
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return fmt::format("Signal: {} (PC: 0x{:X})", strsignal(signal), reinterpret_cast<uintptr_t>(pc));
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else
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return fmt::format("Signal: {} @ 0x{:X} (PC: 0x{:X})", strsignal(signal), reinterpret_cast<uintptr_t>(fault), reinterpret_cast<uintptr_t>(pc));
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}
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};
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/**
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* @brief A signal handler which automatically throws an exception with the corresponding signal metadata in a SignalException
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* @note A termination handler is set in this which prevents any termination from going through as to break out of 'noexcept', do not use std::terminate in a catch clause for this exception
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*/
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void ExceptionalSignalHandler(int signal, siginfo *, ucontext *context);
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/**
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* @brief Our delegator for sigaction, we need to do this due to sigchain hooking bionic's sigaction and it intercepting signals before they're passed onto userspace
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* This not only leads to performance degradation but also requires host TLS to be in the TLS register which we cannot ensure for in-guest signals
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*/
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void Sigaction(int signal, const struct sigaction *action, struct sigaction *oldAction = nullptr);
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/**
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* @brief If the TLS value of the code running prior to a signal has a custom TLS value, this should be used to restore it
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* @param function A function which is inert if the TLS isn't required to be restored, it should return nullptr if TLS wasn't restored else the old TLS value
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*/
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void SetTlsRestorer(void *(*function)());
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using SignalHandler = void (*)(int, struct siginfo *, ucontext *, void **);
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/**
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* @brief A wrapper around Sigaction to make it easy to set a sigaction signal handler for multiple signals and also allow for thread-local signal handlers
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* @param function A sa_action callback with a pointer to the old TLS (If present) as the 4th argument
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* @note If 'nullptr' is written into the 4th argument then the old TLS won't be restored or it'll be set to any non-null value written into it
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*/
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void SetSignalHandler(std::initializer_list<int> signals, SignalHandler function);
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inline void SetSignalHandler(std::initializer_list<int> signals, void (*function)(int, struct siginfo *, ucontext *)) {
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SetSignalHandler(signals, reinterpret_cast<SignalHandler>(function));
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}
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/**
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* @brief Our delegator for sigprocmask, required due to libsigchain hooking this
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*/
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void Sigprocmask(int how, const sigset_t &set, sigset_t *oldSet = nullptr);
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inline void BlockSignal(std::initializer_list<int> signals) {
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sigset_t set{};
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for (int signal : signals)
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sigaddset(&set, signal);
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Sigprocmask(SIG_BLOCK, set, nullptr);
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}
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}
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