зеркало из https://github.com/mozilla/pjs.git
127 строки
2.6 KiB
C++
127 строки
2.6 KiB
C++
/*
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typeinfo.cpp
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Speculatively use RTTI on a random object. If it contains a pointer at offset 0
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that is in the current process' address space, and that so on, then attempt to
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use C++ RTTI's typeid operation to obtain the name of the type.
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by Patrick C. Beard.
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*/
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#include <typeinfo>
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#include <ctype.h>
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#include "gcconfig.h"
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extern "C" const char* getTypeName(void* ptr);
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class IUnknown {
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public:
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virtual long QueryInterface() = 0;
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virtual long AddRef() = 0;
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virtual long Release() = 0;
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};
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#if defined(MACOS)
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#include <Processes.h>
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class AddressSpace {
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public:
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AddressSpace();
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Boolean contains(void* ptr);
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private:
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ProcessInfoRec mInfo;
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};
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AddressSpace::AddressSpace()
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{
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ProcessSerialNumber psn = { 0, kCurrentProcess };
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mInfo.processInfoLength = sizeof(mInfo);
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::GetProcessInformation(&psn, &mInfo);
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}
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Boolean AddressSpace::contains(void* ptr)
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{
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UInt32 start = UInt32(mInfo.processLocation);
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return (UInt32(ptr) >= start && UInt32(ptr) < (start + mInfo.processSize));
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}
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const char* getTypeName(void* ptr)
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{
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// construct only one of these per process.
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static AddressSpace space;
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// sanity check the vtable pointer, before trying to use RTTI on the object.
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void** vt = *(void***)ptr;
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if (vt && !(unsigned(vt) & 0x3) && space.contains(vt) && space.contains(*vt)) {
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IUnknown* u = static_cast<IUnknown*>(ptr);
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const char* type = typeid(*u).name();
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// make sure it looks like a C++ identifier.
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if (type && (isalnum(type[0]) || type[0] == '_'))
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return type;
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}
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return "void*";
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}
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#endif
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#if defined(LINUX)
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#include <signal.h>
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#include <setjmp.h>
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static jmp_buf context;
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static void handler(int signum)
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{
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longjmp(context, signum);
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}
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#define attempt() setjmp(context)
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class Signaller {
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public:
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Signaller(int signum);
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~Signaller();
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private:
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typedef void (*handler_t) (int signum);
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int mSignal;
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handler_t mOldHandler;
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};
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Signaller::Signaller(int signum)
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: mSignal(signum), mOldHandler(signal(signum, &handler))
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{
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}
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Signaller::~Signaller()
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{
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signal(mSignal, mOldHandler);
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}
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const char* getTypeName(void* ptr)
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{
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#if 0
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// sanity check the vtable pointer, before trying to use RTTI on the object.
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void** vt = *(void***)ptr;
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if (vt && !(unsigned(vt) & 3)) {
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Signaller s1(SIGSEGV), s2(SIGILL);
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if (attempt() == 0) {
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IUnknown* u = static_cast<IUnknown*>(ptr);
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const char* type = typeid(*u).name();
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// make sure it looks like a C++ identifier.
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if (type && (isalnum(type[0]) || type[0] == '_')) {
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// ECGS seems to prefix a length string.
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while (isdigit(*type)) ++type;
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return type;
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}
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}
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}
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#endif
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return "void*";
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}
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#endif
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