зеркало из https://github.com/mozilla/pjs.git
293 строки
8.1 KiB
C++
293 строки
8.1 KiB
C++
/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
|
|
*
|
|
* The contents of this file are subject to the Mozilla Public
|
|
* License Version 1.1 (the "License"); you may not use this file
|
|
* except in compliance with the License. You may obtain a copy of
|
|
* the License at http://www.mozilla.org/MPL/
|
|
*
|
|
* Software distributed under the License is distributed on an "AS
|
|
* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
|
|
* implied. See the License for the specific language governing
|
|
* rights and limitations under the License.
|
|
*
|
|
* The Original Code is nsTypeInfo.cpp code, released
|
|
* November 27, 2000.
|
|
*
|
|
* The Initial Developer of the Original Code is Netscape
|
|
* Communications Corporation. Portions created by Netscape are
|
|
* Copyright (C) 2000 Netscape Communications Corporation. All
|
|
* Rights Reserved.
|
|
*
|
|
* Contributor(s):
|
|
* Patrick C. Beard <beard@netscape.com>
|
|
* Chris Waterson <waterson@netscape.com>
|
|
*
|
|
* Alternatively, the contents of this file may be used under the
|
|
* terms of the GNU Public License (the "GPL"), in which case the
|
|
* provisions of the GPL are applicable instead of those above.
|
|
* If you wish to allow use of your version of this file only
|
|
* under the terms of the GPL and not to allow others to use your
|
|
* version of this file under the MPL, indicate your decision by
|
|
* deleting the provisions above and replace them with the notice
|
|
* and other provisions required by the GPL. If you do not delete
|
|
* the provisions above, a recipient may use your version of this
|
|
* file under either the MPL or the GPL.
|
|
*/
|
|
|
|
/*
|
|
typeinfo.cpp
|
|
|
|
Speculatively use RTTI on a random object. If it contains a pointer at offset 0
|
|
that is in the current process' address space, and that so on, then attempt to
|
|
use C++ RTTI's typeid operation to obtain the name of the type.
|
|
|
|
by Patrick C. Beard.
|
|
*/
|
|
|
|
#include <typeinfo>
|
|
#include <ctype.h>
|
|
|
|
extern "C" const char* nsGetTypeName(void* ptr);
|
|
|
|
class IUnknown {
|
|
public:
|
|
virtual long QueryInterface() = 0;
|
|
virtual long AddRef() = 0;
|
|
virtual long Release() = 0;
|
|
};
|
|
|
|
#if defined(MACOS)
|
|
|
|
#include <Processes.h>
|
|
|
|
class AddressSpace {
|
|
public:
|
|
AddressSpace();
|
|
Boolean contains(void* ptr);
|
|
private:
|
|
ProcessInfoRec mInfo;
|
|
};
|
|
|
|
AddressSpace::AddressSpace()
|
|
{
|
|
ProcessSerialNumber psn = { 0, kCurrentProcess };
|
|
mInfo.processInfoLength = sizeof(mInfo);
|
|
::GetProcessInformation(&psn, &mInfo);
|
|
}
|
|
|
|
Boolean AddressSpace::contains(void* ptr)
|
|
{
|
|
UInt32 start = UInt32(mInfo.processLocation);
|
|
return (UInt32(ptr) >= start && UInt32(ptr) < (start + mInfo.processSize));
|
|
}
|
|
|
|
const char* nsGetTypeName(void* ptr)
|
|
{
|
|
// construct only one of these per process.
|
|
static AddressSpace space;
|
|
|
|
// sanity check the vtable pointer, before trying to use RTTI on the object.
|
|
void** vt = *(void***)ptr;
|
|
if (vt && !(unsigned(vt) & 0x3) && space.contains(vt) && space.contains(*vt)) {
|
|
IUnknown* u = static_cast<IUnknown*>(ptr);
|
|
const char* type = typeid(*u).name();
|
|
// make sure it looks like a C++ identifier.
|
|
if (type && (isalnum(type[0]) || type[0] == '_'))
|
|
return type;
|
|
}
|
|
return "void*";
|
|
}
|
|
|
|
#endif
|
|
|
|
// New, more "portable" Linux code is below, but this might be a useful
|
|
// model for other platforms, so keeping.
|
|
//#if defined(linux)
|
|
#if 0
|
|
|
|
#include <signal.h>
|
|
#include <setjmp.h>
|
|
|
|
static jmp_buf context;
|
|
|
|
static void handler(int signum)
|
|
{
|
|
longjmp(context, signum);
|
|
}
|
|
|
|
#define attempt() setjmp(context)
|
|
|
|
class Signaller {
|
|
public:
|
|
Signaller(int signum);
|
|
~Signaller();
|
|
|
|
private:
|
|
typedef void (*handler_t) (int signum);
|
|
int mSignal;
|
|
handler_t mOldHandler;
|
|
};
|
|
|
|
Signaller::Signaller(int signum)
|
|
: mSignal(signum), mOldHandler(signal(signum, &handler))
|
|
{
|
|
}
|
|
|
|
Signaller::~Signaller()
|
|
{
|
|
signal(mSignal, mOldHandler);
|
|
}
|
|
|
|
// The following are pointers that bamboozle our otherwise feeble
|
|
// attempts to "safely" collect type names.
|
|
//
|
|
// XXX this kind of sucks because it means that anyone trying to use
|
|
// this without NSPR will get unresolved symbols when this library
|
|
// loads. It's also not very extensible. Oh well: FIX ME!
|
|
extern "C" {
|
|
// from nsprpub/pr/src/io/priometh.c (libnspr4.so)
|
|
extern void* _pr_faulty_methods;
|
|
};
|
|
|
|
static inline int
|
|
sanity_check_vtable_i386(void** vt)
|
|
{
|
|
// Now that we're "safe" inside the signal handler, we can
|
|
// start poking around. If we're really an object with
|
|
// RTTI, then the second entry in the vtable should point
|
|
// to a function.
|
|
//
|
|
// Let's see if the second entry:
|
|
//
|
|
// 1) looks like a 4-byte aligned pointer
|
|
//
|
|
// 2) points to something that looks like the following
|
|
// i386 instructions:
|
|
//
|
|
// 55 push %ebp
|
|
// 89e5 mov %esp,%ebp
|
|
// 53 push %ebx
|
|
//
|
|
// or
|
|
//
|
|
// 55 push %ebp
|
|
// 89e5 mov %esp,%ebp
|
|
// 56 push %esi
|
|
//
|
|
// (which is the standard function prologue generated
|
|
// by egcs, plus a ``signature'' instruction that appears
|
|
// in the typeid() function's implementation).
|
|
unsigned char** fp1 = reinterpret_cast<unsigned char**>(vt) + 1;
|
|
|
|
// Does it look like an address?
|
|
unsigned char* ip = *fp1;
|
|
if ((unsigned(ip) & 3) != 0)
|
|
return 0;
|
|
|
|
// Does it look like it refers to the standard prologue?
|
|
static unsigned char prologue[] = { 0x55, 0x89, 0xE5 };
|
|
for (unsigned i = 0; i < sizeof(prologue); ++i)
|
|
if (*ip++ != prologue[i])
|
|
return 0;
|
|
|
|
// Is the next instruction a `push %ebx' or `push %esi'?
|
|
if (*ip == 0x53 || *ip == 0x56) {
|
|
return 1;
|
|
}
|
|
|
|
// Nope. There's another variant that has a `sub' instruction,
|
|
// followed by a `cmpl' and a `jne'. Check for that.
|
|
if (ip[0] == 0x83 && ip[1] == 0xec // sub
|
|
&& ip[3] == 0x83 && ip[4] == 0x3d // cmpl
|
|
&& ip[10] == 0x75 // jne
|
|
) {
|
|
return 1;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static inline int
|
|
sanity_check_vtable_ppc(void** vt)
|
|
{
|
|
// XXX write me!
|
|
return 1;
|
|
}
|
|
|
|
#if defined(__i386)
|
|
# define SANITY_CHECK_VTABLE(vt) (sanity_check_vtable_i386(vt))
|
|
#elif defined(PPC)
|
|
# define SANITY_CHECK_VTABLE(vt) (sanity_check_vtable_ppc(vt))
|
|
#else
|
|
# define SANITY_CHECK_VTABLE(vt) (1)
|
|
#endif
|
|
|
|
const char* nsGetTypeName(void* ptr)
|
|
{
|
|
// sanity check the vtable pointer, before trying to use RTTI on the object.
|
|
void** vt = *(void***)ptr;
|
|
if (vt && !(unsigned(vt) & 3) && (vt != &_pr_faulty_methods)) {
|
|
Signaller s1(SIGSEGV);
|
|
if (attempt() == 0) {
|
|
if (SANITY_CHECK_VTABLE(vt)) {
|
|
// Looks like a function: what the hell, let's call it.
|
|
IUnknown* u = static_cast<IUnknown*>(ptr);
|
|
const char* type = typeid(*u).name();
|
|
// EGCS seems to prefix a length string.
|
|
while (isdigit(*type)) ++type;
|
|
return type;
|
|
}
|
|
}
|
|
}
|
|
return "void*";
|
|
}
|
|
|
|
#endif
|
|
|
|
#if defined(linux)
|
|
|
|
#define __USE_GNU
|
|
#include <dlfcn.h>
|
|
#include <ctype.h>
|
|
#include <string.h>
|
|
|
|
const char* nsGetTypeName(void* ptr)
|
|
{
|
|
#if defined(__GXX_ABI_VERSION) && __GXX_ABI_VERSION >= 100 /* G++ V3 ABI */
|
|
const int expected_offset = 8;
|
|
const char vtable_sym_start[] = "_ZTV";
|
|
const int vtable_sym_start_length = sizeof(vtable_sym_start) - 1;
|
|
#else
|
|
const int expected_offset = 0;
|
|
const char vtable_sym_start[] = "__vt_";
|
|
const int vtable_sym_start_length = sizeof(vtable_sym_start) - 1;
|
|
#endif
|
|
void* vt = *(void**)ptr;
|
|
Dl_info info;
|
|
// If dladdr fails, if we're not at the expected offset in the vtable,
|
|
// or if the symbol name isn't a vtable symbol name, return "void*".
|
|
if ( !dladdr(vt, &info) ||
|
|
((char*)info.dli_saddr) + expected_offset != vt ||
|
|
!info.dli_sname ||
|
|
strncmp(info.dli_sname, vtable_sym_start, vtable_sym_start_length))
|
|
return "void*";
|
|
|
|
// skip the garbage at the beginning of things like
|
|
// __vt_14nsRootBoxFrame (gcc 2.96) or _ZTV14nsRootBoxFrame (gcc 3.0)
|
|
const char* rv = info.dli_sname + vtable_sym_start_length;
|
|
while (*rv && isdigit(*rv))
|
|
++rv;
|
|
return rv;
|
|
}
|
|
|
|
#endif
|
|
|
|
#ifdef XP_WIN32
|
|
const char* nsGetTypeName(void* ptr)
|
|
{
|
|
//TODO: COMPLETE THIS
|
|
return "void*";
|
|
}
|
|
|
|
#endif //XP_WIN32
|