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Several classes for exception handling

, 19 Jan 2002 230K 4.2K 119
C++ wrappers for stack trace, unhandled exception and win32 structured exceptions
exception_exe.zip
Exception.exe
Exception.pdb
exception_src.zip
Exception.dsp
Exception.dsw
Exception.plg
/*
 Copyright (c) 2001 - 2002
 Author: Konstantin Boukreev 
 E-mail: konstantin@mail.primorye.ru 
 Created: 25.12.2001 19:41:07
 Version: 1.0.2

 Permission to use, copy, modify, distribute and sell this software
 and its documentation for any purpose is hereby granted without fee,
 provided that the above copyright notice appear in all copies and
 that both that copyright notice and this permission notice appear
 in supporting documentation.  Konstantin Boukreev makes no representations
 about the suitability of this software for any purpose.
 It is provided "as is" without express or implied warranty.

*/

#include "stdafx.h"
#include "sym_engine.h"

#include <crtdbg.h>
#include <malloc.h> 
#include <tlhelp32.h>

#pragma comment (lib, "dbghelp")

#ifdef VERIFY
#undef VERIFY
#endif // VERIFY

#ifdef _DEBUG
#define VERIFY(x) _ASSERTE(x)
#else
#define VERIFY(x) (x)
#endif //_DEBUG

#define WORK_AROUND_SRCLINE_BUG

#ifdef _DEBUG
//#if 1
// #define SYM_ENGINE_TRACE_SPIN_COUNT
#endif //_DEBUG

///////////////////////////////////////////////////////////////////////

bool IsNT()
{	
	#if 1
	OSVERSIONINFO vi = { sizeof(vi)};	
	::GetVersionEx(&vi);
	return vi.dwPlatformId == VER_PLATFORM_WIN32_NT;
	#else
	return false;
	#endif
}

HANDLE SymGetProcessHandle()
{
	if (IsNT())
//	if (0)
		return GetCurrentProcess();
	else
		return (HANDLE)GetCurrentProcessId();
}

BOOL __stdcall My_ReadProcessMemory (HANDLE, LPCVOID lpBaseAddress, LPVOID lpBuffer, DWORD nSize, LPDWORD lpNumberOfBytesRead)
{
    return ReadProcessMemory(GetCurrentProcess(), lpBaseAddress, lpBuffer, nSize, lpNumberOfBytesRead);
}

///////////////////////////////////////////////////////////////////////

sym_engine::sym_engine (unsigned address) 
	: m_address(address), m_ok(false), m_pframe(0)
{
}

sym_engine::~sym_engine()
{
//	if (m_ok) guard::instance().clear();
	delete m_pframe;
}

unsigned sym_engine::module(char * buf, unsigned len)
{
	if (!len || !buf || IsBadWritePtr(buf, len))
		return 0;

	if (!check())
		return 0;

	HANDLE hProc = SymGetProcessHandle();
	HMODULE hMod = (HMODULE)SymGetModuleBase (hProc, m_address);
	if (!hMod) return 0;
	return get_module_basename(hMod, buf, len);	
}

unsigned sym_engine::symbol(char * buf, unsigned len, unsigned * pdisplacement)
{
	if (!len || !buf || 
		IsBadWritePtr(buf, len) ||
		(pdisplacement && IsBadWritePtr(pdisplacement, sizeof(unsigned))))
		return 0;

	if (!check())
		return 0;

	BYTE symbol [ 512 ] ;
	PIMAGEHLP_SYMBOL pSym = (PIMAGEHLP_SYMBOL)&symbol;
	memset(pSym, 0, sizeof(symbol)) ;
	pSym->SizeOfStruct = sizeof(IMAGEHLP_SYMBOL) ;
    pSym->MaxNameLength = sizeof(symbol) - sizeof(IMAGEHLP_SYMBOL);

	HANDLE hProc = SymGetProcessHandle();
	DWORD displacement = 0;
	int r = SymGetSymFromAddr(hProc, m_address, &displacement, pSym);
	if (!r) return 0;
	if (pdisplacement) 
		*pdisplacement = displacement;

	r = _snprintf(buf, len, "%s()", pSym->Name);
    
	r = r == -1 ? len - 1 : r;
	buf[r] = 0;	
	return r;
}

unsigned sym_engine::fileline (char * buf, unsigned len, unsigned * pline, unsigned * pdisplacement)
{
	if (!len || !buf || 
		IsBadWritePtr(buf, len) || 
		(pline && IsBadWritePtr(pline, sizeof(unsigned))) || 
		(pdisplacement && IsBadWritePtr(pdisplacement, sizeof(unsigned))))
		return 0;

	if (!check())
		return 0;

	IMAGEHLP_LINE img_line;
	memset(&img_line, 0, sizeof(IMAGEHLP_LINE));
	img_line.SizeOfStruct = sizeof(IMAGEHLP_LINE);

	HANDLE hProc = SymGetProcessHandle();
	unsigned displacement = 0;
	if (!get_line_from_addr(hProc, m_address, &displacement, &img_line))
		return 0;
	if (pdisplacement) 
		*pdisplacement = displacement;
	if (pline) 
		*pline = img_line.LineNumber;
	lstrcpynA(buf, img_line.FileName, len);
	return lstrlenA(buf);
}

bool sym_engine::stack_first (CONTEXT* pctx)
{
	if (!pctx || IsBadReadPtr(pctx, sizeof(CONTEXT))) 
		return false;

	if (!check())
		return false;

	if (!m_pframe) 
	{
		m_pframe = new STACKFRAME;
		if (!m_pframe) return false;
	}
				
	memset(m_pframe, 0, sizeof(STACKFRAME));

    #ifdef _X86_
    m_pframe->AddrPC.Offset       = pctx->Eip;
    m_pframe->AddrPC.Mode         = AddrModeFlat;
    m_pframe->AddrStack.Offset    = pctx->Esp;
    m_pframe->AddrStack.Mode      = AddrModeFlat;
    m_pframe->AddrFrame.Offset    = pctx->Ebp;
    m_pframe->AddrFrame.Mode      = AddrModeFlat;
    #else
    m_pframe->AddrPC.Offset       = (DWORD)pctx->Fir;
    m_pframe->AddrPC.Mode         = AddrModeFlat;
    m_pframe->AddrReturn.Offset   = (DWORD)pctx->IntRa;
    m_pframe->AddrReturn.Mode     = AddrModeFlat;
    m_pframe->AddrStack.Offset    = (DWORD)pctx->IntSp;
    m_pframe->AddrStack.Mode      = AddrModeFlat;
    m_pframe->AddrFrame.Offset    = (DWORD)pctx->IntFp;
    m_pframe->AddrFrame.Mode      = AddrModeFlat;
    #endif

	m_pctx = pctx;
	return stack_next();
}

bool sym_engine::stack_next  ()
{
	if (!m_pframe || !m_pctx) 
	{		
		_ASSERTE(0);
		return false;
	}
		
	if (!m_ok)
	{
		_ASSERTE(0);
		return false;
	}
	
	SetLastError(0);
	HANDLE hProc = SymGetProcessHandle();
	BOOL r = StackWalk (IMAGE_FILE_MACHINE_I386,
				hProc, 
				GetCurrentThread(), 
				m_pframe, 
				m_pctx,
                (PREAD_PROCESS_MEMORY_ROUTINE)My_ReadProcessMemory,
				SymFunctionTableAccess,
                SymGetModuleBase,
				0);

	if (!r || 
		!m_pframe->AddrFrame.Offset)
	{		
		return false;
	}		

	// "Debugging Applications" John Robbins
	// Before I get too carried away and start calculating
	// everything, I need to double-check that the address returned
	// by StackWalk really exists. I've seen cases in which
	// StackWalk returns TRUE but the address doesn't belong to
	// a module in the process.
	DWORD dwModBase = SymGetModuleBase (hProc, m_pframe->AddrPC.Offset);
	if (!dwModBase) 
	{	
		_ASSERTE(0);
		return false;
	}

	address(m_pframe->AddrPC.Offset);
	return true;
}

bool sym_engine::get_line_from_addr (HANDLE hProc, unsigned addr, unsigned * pdisplacement, IMAGEHLP_LINE * pLine)
{	 
	#ifdef WORK_AROUND_SRCLINE_BUG

	// "Debugging Applications" John Robbins
    // The problem is that the symbol engine finds only those source
    // line addresses (after the first lookup) that fall exactly on
    // a zero displacement. I'll walk backward 100 bytes to
    // find the line and return the proper displacement.
    DWORD displacement = 0 ;
    while (!SymGetLineFromAddr (hProc, addr - displacement, (DWORD*)pdisplacement, pLine))
    {        
        if (100 == ++displacement)
            return false;        
    }

	// "Debugging Applications" John Robbins
    // I found the line, and the source line information is correct, so
    // change the displacement if I had to search backward to find the source line.
    if (displacement)    
        *pdisplacement = displacement;    
    return true;

	#else 
    return 0 != SymGetLineFromAddr (hProc, addr, (DWORD *) pdisplacement, pLine);
	#endif
}

unsigned sym_engine::get_module_basename (HMODULE hMod, char * buf, unsigned len)
{
	char filename[MAX_PATH];
	DWORD r = GetModuleFileNameA(hMod, filename, MAX_PATH);
	if (!r) return 0;
	
	char * p = 0;

	// Find the last '\' mark.
	int i = r - 1;
	for (; i >= 0; i--)
	{	
		if (filename[i] == '\\') 
		{
			p = &filename[i + 1]; 
			break;
		} 
	}

	if (!p)
	{
		i = 0;
		p = filename;
	}
	
	
	len = (len - 1 < r - i - 1) ? len - 1 : r - i - 1;
//	len = min(len - 1, r - i - 1);
	memcpy(buf, p, len);
	buf[len] = 0;
	return len;
}

bool sym_engine::check()
{	
	if (!m_ok) 
		m_ok = guard::instance().init(); 
	return m_ok; 
}

sym_engine::guard::guard() 
	: m_ref(0) 
{}

sym_engine::guard::~guard() 
{ 
	clear(); 
}

bool sym_engine::guard::init()
{	
	if (!m_ref) 
	{
		m_ref = -1;
		
		HANDLE hProc = SymGetProcessHandle();
		DWORD  dwPid = GetCurrentProcessId();

		// initializes
		SymSetOptions (SymGetOptions()|SYMOPT_DEFERRED_LOADS|SYMOPT_LOAD_LINES);
	//	SymSetOptions (SYMOPT_UNDNAME|SYMOPT_LOAD_LINES);
		if (::SymInitialize(hProc, 0, TRUE))
		{			
			// enumerate modules
			if (IsNT())		
			{
				typedef BOOL (WINAPI *ENUMPROCESSMODULES)(HANDLE, HMODULE*, DWORD, LPDWORD);

				HINSTANCE hInst = LoadLibrary(_T("psapi.dll"));
				if (hInst)
				{				
					ENUMPROCESSMODULES fnEnumProcessModules = 
						(ENUMPROCESSMODULES)GetProcAddress(hInst, "EnumProcessModules");
					DWORD cbNeeded = 0;
					if (fnEnumProcessModules &&
						fnEnumProcessModules(GetCurrentProcess(), 0, 0, &cbNeeded) &&
						cbNeeded)
					{	
						HMODULE * pmod = (HMODULE *)alloca(cbNeeded);
						DWORD cb = cbNeeded;
						if (fnEnumProcessModules(GetCurrentProcess(), pmod, cb, &cbNeeded))
						{
							m_ref = 0;
							for (unsigned i = 0; i < cb / sizeof (HMODULE); ++i)
							{								
								if (!load_module(hProc, pmod[i]))
								{
								//	m_ref = -1;
								//	break;
									_ASSERTE(0);
								}									
							}							
						}
					}
					else
					{
						_ASSERTE(0);
					}
					VERIFY(FreeLibrary(hInst));
				}
				else
				{
					_ASSERTE(0);
				}
			}
			else
			{
				typedef HANDLE (WINAPI *CREATESNAPSHOT)(DWORD, DWORD);
				typedef BOOL (WINAPI *MODULEWALK)(HANDLE, LPMODULEENTRY32);

				HMODULE hMod = GetModuleHandle(_T("kernel32"));
				CREATESNAPSHOT fnCreateToolhelp32Snapshot = (CREATESNAPSHOT)GetProcAddress(hMod, "CreateToolhelp32Snapshot");
				MODULEWALK fnModule32First = (MODULEWALK)GetProcAddress(hMod, "Module32First");
				MODULEWALK fnModule32Next  = (MODULEWALK)GetProcAddress(hMod, "Module32Next");

				if (fnCreateToolhelp32Snapshot && 
					fnModule32First && 
					fnModule32Next)
				{				
					HANDLE hModSnap = fnCreateToolhelp32Snapshot(TH32CS_SNAPMODULE, dwPid);
					if (hModSnap)
					{
						MODULEENTRY32 me32 = {0};						 
						me32.dwSize = sizeof(MODULEENTRY32);
						if (fnModule32First(hModSnap, &me32))
						{
							m_ref = 0;
							do
							{
								if (!load_module(hProc, me32.hModule))
								{
								//	m_ref = -1;
								//	break;
								}																	
							}
							while(fnModule32Next(hModSnap, &me32));
						}
						VERIFY(CloseHandle(hModSnap));						
					}
				}
			}

			if (m_ref == -1)
			{				
				VERIFY(SymCleanup(SymGetProcessHandle()));
			}
		}
		else
		{
			_ASSERTE(0);
		}
	}
	if (m_ref == -1)
		return false;
	if (0 == m_ref) 
		++m_ref; // lock it once
//	++m_ref;
	return true;
}

void sym_engine::guard::clear()
{
	if (m_ref ==  0) return;
	if (m_ref == -1) return;	
	if (--m_ref == 0)
	{	 
		VERIFY(SymCleanup(SymGetProcessHandle()));
	}
}

bool sym_engine::guard::load_module(HANDLE hProcess, HMODULE hMod)
{	
	char filename[MAX_PATH];
	if (!GetModuleFileNameA(hMod, filename, MAX_PATH))
		return false;
	
	HANDLE hFile = CreateFileA(filename, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, 0, 0);
	if (hFile == INVALID_HANDLE_VALUE) return false;

	// "Debugging Applications" John Robbins	
    // For whatever reason, SymLoadModule can return zero, but it still loads the modules. Sheez.
	SetLastError(ERROR_SUCCESS);
    if (!SymLoadModule(hProcess, hFile, filename, 0, (DWORD)hMod, 0) && 
		ERROR_SUCCESS != GetLastError())
	{
		return false;
	}
	
	return true;
}

bool sym_engine::stack_trace(std::ostream& os, CONTEXT * pctx, unsigned skip, const char * fmt)
{
	if (!fmt) return false;	
	sym_engine sym(0);
	return stack_trace(os, sym, pctx, skip, fmt);	
}

/////////////////////////////////////////////
// prints a current thread's stack

struct current_context : CONTEXT
{
	HANDLE	thread;	 
	volatile int signal;
};

static DWORD WINAPI tproc(void * pv)
{		
	current_context * p = reinterpret_cast<current_context*>(pv);
	
	__try
	{	
		// Konstantin, 14.01.2002 17:21:32
		// must wait in spin lock until main thread will leave a ResumeThread (must return back to user context)
		unsigned debug_only = 0;
		while (p->signal) 
		{		
			if (!SwitchToThread())
				Sleep(20); // forces switch to another thread 
			++debug_only;
		}
		#ifdef SYM_ENGINE_TRACE_SPIN_COUNT
		char s[256];
		wsprintf(s, "sym_engine::tproc, spin count %u\n", debug_only);
		OutputDebugString(s);
		#endif;
		
		if (-1 == SuspendThread(p->thread)) 
		{
			p->signal  = -1;
			__leave;
		}
		
		__try
		{
			p->signal = GetThreadContext(p->thread, p) ? 1 : -1;
		}
		__finally
		{
			VERIFY(-1 != ResumeThread(p->thread));
		}		
	}
	__except(EXCEPTION_EXECUTE_HANDLER)
	{	
		p->signal  = -1;
	}	
	return 0;
}

bool sym_engine::stack_trace(std::ostream& os, unsigned skip, const char * fmt)
{
	if (!fmt) return false;

	// attempts to get current thread's context
	
	current_context ctx;
	memset(&ctx, 0, sizeof current_context);

	BOOL r = DuplicateHandle(GetCurrentProcess(), GetCurrentThread(), GetCurrentProcess(), 
		&ctx.thread, 0, 0, DUPLICATE_SAME_ACCESS);

	_ASSERTE(r);
	_ASSERTE(ctx.thread);

	if (!r || !ctx.thread)
		return false;

	ctx.ContextFlags = CONTEXT_CONTROL; // CONTEXT_FULL;
	ctx.signal = -1;

	DWORD dummy;		
	HANDLE worker = CreateThread(0, 0, tproc, &ctx, CREATE_SUSPENDED, &dummy);	
	_ASSERTE(worker);

	if (worker)
	{
		 VERIFY(SetThreadPriority(worker, THREAD_PRIORITY_ABOVE_NORMAL)); //  THREAD_PRIORITY_HIGHEST
		if (-1 != ResumeThread(worker))
		{
			unsigned debug_only = 0;
										// Konstantin, 14.01.2002 17:21:32
			ctx.signal = 0;				// only now the worker thread can get this thread context
			while (!ctx.signal)
				++debug_only; // wait in spin		
			#ifdef SYM_ENGINE_TRACE_SPIN_COUNT
			char s[256];
			wsprintf(s, "sym_engine::stack_trace, spin count %u\n", debug_only);
			OutputDebugString(s);
			#endif
		}			
		else
		{
			VERIFY(TerminateThread(worker, 0));
		}

		VERIFY(CloseHandle(worker));		
	}
	
	VERIFY(CloseHandle(ctx.thread));

	if (ctx.signal == -1)
	{
		_ASSERTE(0);
		return false;
	}
		
	// now it can print stack	
	sym_engine sym(0);
	stack_trace(os, sym, &ctx, skip, fmt);
	return true;
}

bool sym_engine::stack_trace(std::ostream& os, sym_engine& sym, 
		CONTEXT * pctx, unsigned skip, const char * fmt)
{	
	if (!sym.stack_first(pctx)) 
		return false;
					
	char buf [512] = {0};
	char fbuf[512] = {0};
	char sbuf[512] = {0};

	os << std::dec;
	
	do
	{
		if (!skip)
		{			
			unsigned ln = 0;
			unsigned ld = 0;
			unsigned sd = 0;
			char *   pf	= 0;
			char *   ps = 0;
			
			for (char * p = (char *)fmt; *p; ++p)
			{				
				if (*p == '%')
				{
					++p; // skips '%'
					char c = *p;
					switch (c)
					{
					case 'm':							
						os << (sym.module(buf, sizeof(buf)) ? buf : "?.?");
						break;
					case 'f':
						if (!pf) 							
							pf = (sym.fileline(fbuf, sizeof(fbuf), &ln, &ld)) ? fbuf : " ";
						os << pf;								
						break;
					case 'l':
						if (!pf) 							
							pf = (sym.fileline(fbuf, sizeof(fbuf), &ln, &ld)) ? fbuf : " ";
						if (*(p + 1) == 'd') { os << ld; ++p; }
						else os << ln;							
						break;
					case 's':
						if (!ps)
							ps = sym.symbol(sbuf, sizeof(sbuf), &sd) ? sbuf : "?()";
						if (*(p + 1) == 'd') { os << sd; ++p; }
						else os << ps;
						break;
					case '%':
						os << '%';
						break;
					default:
						os << '%' << c;	// prints unknown format's argument
						break;
					}
				}
				else
				{
					os << *p;
				}
			}
		}
		else
		{
			--skip;
		}
	}
	while (os.good() && sym.stack_next());
	return true;
}

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About the Author

Konstantin Boukreev
Web Developer
Russian Federation Russian Federation
I am freelance programmer. About 3 years of experience in C++ and I would rather use ATL, STL, WTL but not MFC Smile | :) . Main backgrounds are Win32 API, COM and Networking. Now I am interested about AI (Neural Network, Fuzzy Logic and GA). Currently based in Vladivostok, Russia.

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