programs/winedbg/stack.c - wine - Git at Google

 /*
  * Debugger stack handling
  *
  * Copyright 1995 Alexandre Julliard
  * Copyright 1996 Eric Youngdale
  * Copyright 1999 Ove Kåven
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with this library; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */

 #include "config.h"

 #include <stdlib.h>
 #include <stdio.h>

 #include "debugger.h"
 #include "winbase.h"
 #include "wine/winbase16.h"
 #include "wine/debug.h"
 #include "tlhelp32.h"

 WINE_DEFAULT_DEBUG_CHANNEL(winedbg);

 /***********************************************************************
  *           stack_info
  *
  * Dump the top of the stack
  */
 void stack_info(void)
 {
     struct dbg_lvalue lvalue;

     lvalue.cookie = 0;
     lvalue.type.id = dbg_itype_segptr;
     lvalue.type.module = 0;

     /* FIXME: we assume stack grows the same way as on i386 */
     if (!memory_get_current_stack(&lvalue.addr))
         dbg_printf("Bad segment (%d)\n", lvalue.addr.Segment);

     dbg_printf("Stack dump:\n");
     switch (lvalue.addr.Mode)
     {
     case AddrModeFlat: /* 32-bit mode */
     case AddrMode1632: /* 32-bit mode */
         memory_examine(&lvalue, 24, 'x');
         break;
     case AddrModeReal:  /* 16-bit mode */
     case AddrMode1616:
         memory_examine(&lvalue, 24, 'w');
 	break;
     }
 }

 static BOOL stack_set_frame_internal(int newframe)
 {
     if (newframe >= dbg_curr_thread->num_frames)
         newframe = dbg_curr_thread->num_frames - 1;
     if (newframe < 0)
         newframe = 0;

     if (dbg_curr_thread->curr_frame != newframe)
     {
         IMAGEHLP_STACK_FRAME    ihsf;

         dbg_curr_thread->curr_frame = newframe;
         stack_get_current_frame(&ihsf);
         SymSetContext(dbg_curr_process->handle, &ihsf, NULL);
     }
     return TRUE;
 }

 static BOOL stack_get_frame(int nf, IMAGEHLP_STACK_FRAME* ihsf)
 {
     memset(ihsf, 0, sizeof(*ihsf));
     ihsf->InstructionOffset = (unsigned long)memory_to_linear_addr(&dbg_curr_thread->frames[nf].addr_pc);
     ihsf->FrameOffset = (unsigned long)memory_to_linear_addr(&dbg_curr_thread->frames[nf].addr_frame);
     return TRUE;
 }

 BOOL stack_get_current_frame(IMAGEHLP_STACK_FRAME* ihsf)
 {
     /*
      * If we don't have a valid backtrace, then just return.
      */
     if (dbg_curr_thread->frames == NULL) return FALSE;
     return stack_get_frame(dbg_curr_thread->curr_frame, ihsf);
 }

 BOOL stack_set_frame(int newframe)
 {
     ADDRESS     addr;
     if (!stack_set_frame_internal(newframe)) return FALSE;
     addr.Mode = AddrModeFlat;
     addr.Offset = (unsigned long)memory_to_linear_addr(&dbg_curr_thread->frames[dbg_curr_thread->curr_frame].addr_pc);
     source_list_from_addr(&addr, 0);
     return TRUE;
 }

 /******************************************************************
  *		stack_get_current_symbol
  *
  * Retrieves the symbol information for the current frame element
  */
 BOOL stack_get_current_symbol(SYMBOL_INFO* symbol)
 {
     IMAGEHLP_STACK_FRAME        ihsf;
     DWORD64                     disp;

     if (!stack_get_current_frame(&ihsf)) return FALSE;
     return SymFromAddr(dbg_curr_process->handle, ihsf.InstructionOffset,
                        &disp, symbol);
 }

 static BOOL CALLBACK stack_read_mem(HANDLE hProc, DWORD addr,
                                     PVOID buffer, DWORD size, PDWORD written)
 {
     struct dbg_process* pcs = dbg_get_process_h(hProc);
     if (!pcs) return FALSE;
     return pcs->process_io->read(hProc, (const void*)addr, buffer, size, written);
 }

 /******************************************************************
  *		stack_fetch_frames
  *
  * Do a backtrace on the the current thread
  */
 unsigned stack_fetch_frames(void)
 {
     STACKFRAME  sf;
     unsigned    nf = 0;

     HeapFree(GetProcessHeap(), 0, dbg_curr_thread->frames);
     dbg_curr_thread->frames = NULL;

     memset(&sf, 0, sizeof(sf));
     memory_get_current_frame(&sf.AddrFrame);
     memory_get_current_pc(&sf.AddrPC);

     /* don't confuse StackWalk by passing in inconsistent addresses */
     if ((sf.AddrPC.Mode == AddrModeFlat) && (sf.AddrFrame.Mode != AddrModeFlat))
     {
         sf.AddrFrame.Offset = (DWORD)memory_to_linear_addr(&sf.AddrFrame);
         sf.AddrFrame.Mode = AddrModeFlat;
     }

     while (StackWalk(IMAGE_FILE_MACHINE_I386, dbg_curr_process->handle,
                      dbg_curr_thread->handle, &sf, &dbg_context, stack_read_mem,
                      SymFunctionTableAccess, SymGetModuleBase, NULL))
     {
         dbg_curr_thread->frames = dbg_heap_realloc(dbg_curr_thread->frames,
                                                    (nf + 1) * sizeof(dbg_curr_thread->frames[0]));

         dbg_curr_thread->frames[nf].addr_pc = sf.AddrPC;
         dbg_curr_thread->frames[nf].addr_frame = sf.AddrFrame;
         nf++;
         /* we've probably gotten ourselves into an infinite loop so bail */
         if (nf > 200) break;
     }
     dbg_curr_thread->curr_frame = -1;
     dbg_curr_thread->num_frames = nf;
     stack_set_frame_internal(0);
     return nf;
 }

 struct sym_enum
 {
     char*       tmp;
     DWORD       frame;
 };

 static BOOL WINAPI sym_enum_cb(SYMBOL_INFO* sym_info, ULONG size, void* user)
 {
     struct sym_enum*    se = (struct sym_enum*)user;
     char                tmp[32];

     if (sym_info->Flags & SYMFLAG_PARAMETER)
     {
         if (se->tmp[0]) strcat(se->tmp, ", ");

         if (sym_info->Flags & SYMFLAG_REGREL)
         {
             unsigned    val;
             DWORD       addr = se->frame + sym_info->Address;

             if (!dbg_read_memory((char*)addr, &val, sizeof(val)))
                 snprintf(tmp, sizeof(tmp), "<*** cannot read at 0x%lx ***>", addr);
             else
                 snprintf(tmp, sizeof(tmp), "0x%x", val);
         }
         else if (sym_info->Flags & SYMFLAG_REGISTER)
         {
             DWORD* pval;

             if (memory_get_register(sym_info->Register, &pval, tmp, sizeof(tmp)))
                 snprintf(tmp, sizeof(tmp), "0x%lx", *pval);
         }
         sprintf(se->tmp + strlen(se->tmp), "%s=%s", sym_info->Name, tmp);
     }
     return TRUE;
 }

 static void stack_print_addr_and_args(int nf)
 {
     char                        buffer[sizeof(SYMBOL_INFO) + 256];
     SYMBOL_INFO*                si = (SYMBOL_INFO*)buffer;
     IMAGEHLP_STACK_FRAME        ihsf;
     IMAGEHLP_LINE               il;
     IMAGEHLP_MODULE             im;
     DWORD64                     disp64;

     print_bare_address(&dbg_curr_thread->frames[nf].addr_pc);

     stack_get_frame(nf, &ihsf);

     /* grab module where symbol is. If we don't have a module, we cannot print more */
     im.SizeOfStruct = sizeof(im);
     if (!SymGetModuleInfo(dbg_curr_process->handle, ihsf.InstructionOffset, &im))
         return;

     si->SizeOfStruct = sizeof(*si);
     si->MaxNameLen   = 256;
     if (SymFromAddr(dbg_curr_process->handle, ihsf.InstructionOffset, &disp64, si))
     {
         struct sym_enum se;
         char            tmp[1024];
         DWORD           disp;

         dbg_printf(" %s", si->Name);
         if (disp64) dbg_printf("+0x%lx", (DWORD_PTR)disp64);

         SymSetContext(dbg_curr_process->handle, &ihsf, NULL);
         se.tmp = tmp;
         se.frame = ihsf.FrameOffset;
         tmp[0] = '\0';
         SymEnumSymbols(dbg_curr_process->handle, 0, NULL, sym_enum_cb, &se);
         if (tmp[0]) dbg_printf("(%s)", tmp);

         il.SizeOfStruct = sizeof(il);
         if (SymGetLineFromAddr(dbg_curr_process->handle, ihsf.InstructionOffset,
                                &disp, &il))
             dbg_printf(" [%s:%lu]", il.FileName, il.LineNumber);
         dbg_printf(" in %s", im.ModuleName);
     }
     else dbg_printf(" in %s (+0x%lx)",
                     im.ModuleName, (DWORD_PTR)(ihsf.InstructionOffset - im.BaseOfImage));
 }

 /******************************************************************
  *		backtrace
  *
  * Do a backtrace on the the current thread
  */
 static void backtrace(void)
 {
     unsigned                    cf = dbg_curr_thread->curr_frame;
     IMAGEHLP_STACK_FRAME        ihsf;

     dbg_printf("Backtrace:\n");
     for (dbg_curr_thread->curr_frame = 0;
          dbg_curr_thread->curr_frame < dbg_curr_thread->num_frames;
          dbg_curr_thread->curr_frame++)
     {
         dbg_printf("%s%d ",
                    (cf == dbg_curr_thread->curr_frame ? "=>" : "  "),
                    dbg_curr_thread->curr_frame + 1);
         stack_print_addr_and_args(dbg_curr_thread->curr_frame);
         dbg_printf(" (");
         print_bare_address(&dbg_curr_thread->frames[dbg_curr_thread->curr_frame].addr_pc);
         dbg_printf(")\n");
     }
     /* reset context to current stack frame */
     dbg_curr_thread->curr_frame = cf;
     stack_get_frame(dbg_curr_thread->curr_frame, &ihsf);
     SymSetContext(dbg_curr_process->handle, &ihsf, NULL);
 }

 /******************************************************************
  *		backtrace_tid
  *
  * Do a backtrace on a thread from its process and its identifier
  * (preserves current thread and context information)
  */
 static void backtrace_tid(struct dbg_process* pcs, DWORD tid)
 {
     struct dbg_thread*  thread = dbg_curr_thread;

     if (!(dbg_curr_thread = dbg_get_thread(pcs, tid)))
         dbg_printf("Unknown thread id (0x%lx) in process (0x%lx)\n", tid, pcs->pid);
     else
     {
         CONTEXT saved_ctx = dbg_context;

         dbg_curr_tid = dbg_curr_thread->tid;
         memset(&dbg_context, 0, sizeof(dbg_context));
         dbg_context.ContextFlags = CONTEXT_FULL;
         if (SuspendThread(dbg_curr_thread->handle) != -1)
         {
             if (!GetThreadContext(dbg_curr_thread->handle, &dbg_context))
             {
                 dbg_printf("Can't get context for thread 0x%lx in current process\n",
                            tid);
             }
             else backtrace();
             ResumeThread(dbg_curr_thread->handle);
         }
         else dbg_printf("Can't suspend thread 0x%lx in current process\n", tid);
         dbg_context = saved_ctx;
     }
     dbg_curr_thread = thread;
     dbg_curr_tid = thread ? thread->tid : 0;
 }

 /******************************************************************
  *		backtrace_all
  *
  * Do a backtrace on every running thread in the system (except the debugger)
  * (preserves current process information)
  */
 static void backtrace_all(void)
 {
     THREADENTRY32       entry;
     HANDLE              snapshot = CreateToolhelp32Snapshot(TH32CS_SNAPTHREAD, 0);

     if (snapshot == INVALID_HANDLE_VALUE)
     {
         dbg_printf("Unable to create toolhelp snapshot\n");
         return;
     }

     entry.dwSize = sizeof(entry);
     if (Thread32First(snapshot, &entry))
     {
         do
         {
             if (entry.th32OwnerProcessID == GetCurrentProcessId()) continue;
             if (dbg_curr_process && dbg_curr_pid != entry.th32OwnerProcessID)
                 dbg_curr_process->process_io->close_process(dbg_curr_process, FALSE);

             if (entry.th32OwnerProcessID != dbg_curr_pid)
             {
                 if (!dbg_attach_debuggee(entry.th32OwnerProcessID, FALSE, TRUE))
                 {
                     dbg_printf("\nwarning: could not attach to 0x%lx\n",
                                entry.th32OwnerProcessID);
                     continue;
                 }
                 dbg_curr_pid = dbg_curr_process->pid;
             }

             dbg_printf("\nBacktracing for thread 0x%lx in process 0x%lx (%s):\n",
                        entry.th32ThreadID, dbg_curr_pid, dbg_curr_process->imageName);
             backtrace_tid(dbg_curr_process, entry.th32ThreadID);
         }
         while (Thread32Next(snapshot, &entry));

         if (dbg_curr_process)
             dbg_curr_process->process_io->close_process(dbg_curr_process, FALSE);
     }
     CloseHandle(snapshot);
 }

 void stack_backtrace(DWORD tid)
 {
     /* backtrace every thread in every process except the debugger itself,
      * invoking via "bt all"
      */
     if (tid == -1) return backtrace_all();

     if (!dbg_curr_process)
     {
         dbg_printf("You must be attached to a process to run this command.\n");
         return;
     }

     if (tid == dbg_curr_tid)
     {
         backtrace();
     }
     else
     {
         backtrace_tid(dbg_curr_process, tid);
     }
 }
	/*
	* Debugger stack handling
	*
	* Copyright 1995 Alexandre Julliard
	* Copyright 1996 Eric Youngdale
	* Copyright 1999 Ove Kåven
	*
	* This library is free software; you can redistribute it and/or
	* modify it under the terms of the GNU Lesser General Public
	* License as published by the Free Software Foundation; either
	* version 2.1 of the License, or (at your option) any later version.
	*
	* This library is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* Lesser General Public License for more details.
	*
	* You should have received a copy of the GNU Lesser General Public
	* License along with this library; if not, write to the Free Software
	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	*/

	#include "config.h"

	#include <stdlib.h>
	#include <stdio.h>

	#include "debugger.h"
	#include "winbase.h"
	#include "wine/winbase16.h"
	#include "wine/debug.h"
	#include "tlhelp32.h"

	WINE_DEFAULT_DEBUG_CHANNEL(winedbg);

	/***********************************************************************
	* stack_info
	*
	* Dump the top of the stack
	*/
	void stack_info(void)
	{
	struct dbg_lvalue lvalue;

	lvalue.cookie = 0;
	lvalue.type.id = dbg_itype_segptr;
	lvalue.type.module = 0;

	/* FIXME: we assume stack grows the same way as on i386 */
	if (!memory_get_current_stack(&lvalue.addr))
	dbg_printf("Bad segment (%d)\n", lvalue.addr.Segment);

	dbg_printf("Stack dump:\n");
	switch (lvalue.addr.Mode)
	{
	case AddrModeFlat: /* 32-bit mode */
	case AddrMode1632: /* 32-bit mode */
	memory_examine(&lvalue, 24, 'x');
	break;
	case AddrModeReal: /* 16-bit mode */
	case AddrMode1616:
	memory_examine(&lvalue, 24, 'w');
	break;
	}
	}

	static BOOL stack_set_frame_internal(int newframe)
	{
	if (newframe >= dbg_curr_thread->num_frames)
	newframe = dbg_curr_thread->num_frames - 1;
	if (newframe < 0)
	newframe = 0;

	if (dbg_curr_thread->curr_frame != newframe)
	{
	IMAGEHLP_STACK_FRAME ihsf;

	dbg_curr_thread->curr_frame = newframe;
	stack_get_current_frame(&ihsf);
	SymSetContext(dbg_curr_process->handle, &ihsf, NULL);
	}
	return TRUE;
	}

	static BOOL stack_get_frame(int nf, IMAGEHLP_STACK_FRAME* ihsf)
	{
	memset(ihsf, 0, sizeof(*ihsf));
	ihsf->InstructionOffset = (unsigned long)memory_to_linear_addr(&dbg_curr_thread->frames[nf].addr_pc);
	ihsf->FrameOffset = (unsigned long)memory_to_linear_addr(&dbg_curr_thread->frames[nf].addr_frame);
	return TRUE;
	}

	BOOL stack_get_current_frame(IMAGEHLP_STACK_FRAME* ihsf)
	{
	/*
	* If we don't have a valid backtrace, then just return.
	*/
	if (dbg_curr_thread->frames == NULL) return FALSE;
	return stack_get_frame(dbg_curr_thread->curr_frame, ihsf);
	}

	BOOL stack_set_frame(int newframe)
	{
	ADDRESS addr;
	if (!stack_set_frame_internal(newframe)) return FALSE;
	addr.Mode = AddrModeFlat;
	addr.Offset = (unsigned long)memory_to_linear_addr(&dbg_curr_thread->frames[dbg_curr_thread->curr_frame].addr_pc);
	source_list_from_addr(&addr, 0);
	return TRUE;
	}

	/******************************************************************
	* stack_get_current_symbol
	*
	* Retrieves the symbol information for the current frame element
	*/
	BOOL stack_get_current_symbol(SYMBOL_INFO* symbol)
	{
	IMAGEHLP_STACK_FRAME ihsf;
	DWORD64 disp;

	if (!stack_get_current_frame(&ihsf)) return FALSE;
	return SymFromAddr(dbg_curr_process->handle, ihsf.InstructionOffset,
	&disp, symbol);
	}

	static BOOL CALLBACK stack_read_mem(HANDLE hProc, DWORD addr,
	PVOID buffer, DWORD size, PDWORD written)
	{
	struct dbg_process* pcs = dbg_get_process_h(hProc);
	if (!pcs) return FALSE;
	return pcs->process_io->read(hProc, (const void*)addr, buffer, size, written);
	}

	/******************************************************************
	* stack_fetch_frames
	*
	* Do a backtrace on the the current thread
	*/
	unsigned stack_fetch_frames(void)
	{
	STACKFRAME sf;
	unsigned nf = 0;

	HeapFree(GetProcessHeap(), 0, dbg_curr_thread->frames);
	dbg_curr_thread->frames = NULL;

	memset(&sf, 0, sizeof(sf));
	memory_get_current_frame(&sf.AddrFrame);
	memory_get_current_pc(&sf.AddrPC);

	/* don't confuse StackWalk by passing in inconsistent addresses */
	if ((sf.AddrPC.Mode == AddrModeFlat) && (sf.AddrFrame.Mode != AddrModeFlat))
	{
	sf.AddrFrame.Offset = (DWORD)memory_to_linear_addr(&sf.AddrFrame);
	sf.AddrFrame.Mode = AddrModeFlat;
	}

	while (StackWalk(IMAGE_FILE_MACHINE_I386, dbg_curr_process->handle,
	dbg_curr_thread->handle, &sf, &dbg_context, stack_read_mem,
	SymFunctionTableAccess, SymGetModuleBase, NULL))
	{
	dbg_curr_thread->frames = dbg_heap_realloc(dbg_curr_thread->frames,
	(nf + 1) * sizeof(dbg_curr_thread->frames[0]));

	dbg_curr_thread->frames[nf].addr_pc = sf.AddrPC;
	dbg_curr_thread->frames[nf].addr_frame = sf.AddrFrame;
	nf++;
	/* we've probably gotten ourselves into an infinite loop so bail */
	if (nf > 200) break;
	}
	dbg_curr_thread->curr_frame = -1;
	dbg_curr_thread->num_frames = nf;
	stack_set_frame_internal(0);
	return nf;
	}

	struct sym_enum
	{
	char* tmp;
	DWORD frame;
	};

	static BOOL WINAPI sym_enum_cb(SYMBOL_INFO* sym_info, ULONG size, void* user)
	{
	struct sym_enum* se = (struct sym_enum*)user;
	char tmp[32];

	if (sym_info->Flags & SYMFLAG_PARAMETER)
	{
	if (se->tmp[0]) strcat(se->tmp, ", ");

	if (sym_info->Flags & SYMFLAG_REGREL)
	{
	unsigned val;
	DWORD addr = se->frame + sym_info->Address;

	if (!dbg_read_memory((char*)addr, &val, sizeof(val)))
	snprintf(tmp, sizeof(tmp), "<* cannot read at 0x%lx *>", addr);
	else
	snprintf(tmp, sizeof(tmp), "0x%x", val);
	}
	else if (sym_info->Flags & SYMFLAG_REGISTER)
	{
	DWORD* pval;

	if (memory_get_register(sym_info->Register, &pval, tmp, sizeof(tmp)))
	snprintf(tmp, sizeof(tmp), "0x%lx", *pval);
	}
	sprintf(se->tmp + strlen(se->tmp), "%s=%s", sym_info->Name, tmp);
	}
	return TRUE;
	}

	static void stack_print_addr_and_args(int nf)
	{
	char buffer[sizeof(SYMBOL_INFO) + 256];
	SYMBOL_INFO* si = (SYMBOL_INFO*)buffer;
	IMAGEHLP_STACK_FRAME ihsf;
	IMAGEHLP_LINE il;
	IMAGEHLP_MODULE im;
	DWORD64 disp64;

	print_bare_address(&dbg_curr_thread->frames[nf].addr_pc);

	stack_get_frame(nf, &ihsf);

	/* grab module where symbol is. If we don't have a module, we cannot print more */
	im.SizeOfStruct = sizeof(im);
	if (!SymGetModuleInfo(dbg_curr_process->handle, ihsf.InstructionOffset, &im))
	return;

	si->SizeOfStruct = sizeof(*si);
	si->MaxNameLen = 256;
	if (SymFromAddr(dbg_curr_process->handle, ihsf.InstructionOffset, &disp64, si))
	{
	struct sym_enum se;
	char tmp[1024];
	DWORD disp;

	dbg_printf(" %s", si->Name);
	if (disp64) dbg_printf("+0x%lx", (DWORD_PTR)disp64);

	SymSetContext(dbg_curr_process->handle, &ihsf, NULL);
	se.tmp = tmp;
	se.frame = ihsf.FrameOffset;
	tmp[0] = '\0';
	SymEnumSymbols(dbg_curr_process->handle, 0, NULL, sym_enum_cb, &se);
	if (tmp[0]) dbg_printf("(%s)", tmp);

	il.SizeOfStruct = sizeof(il);
	if (SymGetLineFromAddr(dbg_curr_process->handle, ihsf.InstructionOffset,
	&disp, &il))
	dbg_printf(" [%s:%lu]", il.FileName, il.LineNumber);
	dbg_printf(" in %s", im.ModuleName);
	}
	else dbg_printf(" in %s (+0x%lx)",
	im.ModuleName, (DWORD_PTR)(ihsf.InstructionOffset - im.BaseOfImage));
	}

	/******************************************************************
	* backtrace
	*
	* Do a backtrace on the the current thread
	*/
	static void backtrace(void)
	{
	unsigned cf = dbg_curr_thread->curr_frame;
	IMAGEHLP_STACK_FRAME ihsf;

	dbg_printf("Backtrace:\n");
	for (dbg_curr_thread->curr_frame = 0;
	dbg_curr_thread->curr_frame < dbg_curr_thread->num_frames;
	dbg_curr_thread->curr_frame++)
	{
	dbg_printf("%s%d ",
	(cf == dbg_curr_thread->curr_frame ? "=>" : " "),
	dbg_curr_thread->curr_frame + 1);
	stack_print_addr_and_args(dbg_curr_thread->curr_frame);
	dbg_printf(" (");
	print_bare_address(&dbg_curr_thread->frames[dbg_curr_thread->curr_frame].addr_pc);
	dbg_printf(")\n");
	}
	/* reset context to current stack frame */
	dbg_curr_thread->curr_frame = cf;
	stack_get_frame(dbg_curr_thread->curr_frame, &ihsf);
	SymSetContext(dbg_curr_process->handle, &ihsf, NULL);
	}

	/******************************************************************
	* backtrace_tid
	*
	* Do a backtrace on a thread from its process and its identifier
	* (preserves current thread and context information)
	*/
	static void backtrace_tid(struct dbg_process* pcs, DWORD tid)
	{
	struct dbg_thread* thread = dbg_curr_thread;

	if (!(dbg_curr_thread = dbg_get_thread(pcs, tid)))
	dbg_printf("Unknown thread id (0x%lx) in process (0x%lx)\n", tid, pcs->pid);
	else
	{
	CONTEXT saved_ctx = dbg_context;

	dbg_curr_tid = dbg_curr_thread->tid;
	memset(&dbg_context, 0, sizeof(dbg_context));
	dbg_context.ContextFlags = CONTEXT_FULL;
	if (SuspendThread(dbg_curr_thread->handle) != -1)
	{
	if (!GetThreadContext(dbg_curr_thread->handle, &dbg_context))
	{
	dbg_printf("Can't get context for thread 0x%lx in current process\n",
	tid);
	}
	else backtrace();
	ResumeThread(dbg_curr_thread->handle);
	}
	else dbg_printf("Can't suspend thread 0x%lx in current process\n", tid);
	dbg_context = saved_ctx;
	}
	dbg_curr_thread = thread;
	dbg_curr_tid = thread ? thread->tid : 0;
	}

	/******************************************************************
	* backtrace_all
	*
	* Do a backtrace on every running thread in the system (except the debugger)
	* (preserves current process information)
	*/
	static void backtrace_all(void)
	{
	THREADENTRY32 entry;
	HANDLE snapshot = CreateToolhelp32Snapshot(TH32CS_SNAPTHREAD, 0);

	if (snapshot == INVALID_HANDLE_VALUE)
	{
	dbg_printf("Unable to create toolhelp snapshot\n");
	return;
	}

	entry.dwSize = sizeof(entry);
	if (Thread32First(snapshot, &entry))
	{
	do
	{
	if (entry.th32OwnerProcessID == GetCurrentProcessId()) continue;
	if (dbg_curr_process && dbg_curr_pid != entry.th32OwnerProcessID)
	dbg_curr_process->process_io->close_process(dbg_curr_process, FALSE);

	if (entry.th32OwnerProcessID != dbg_curr_pid)
	{
	if (!dbg_attach_debuggee(entry.th32OwnerProcessID, FALSE, TRUE))
	{
	dbg_printf("\nwarning: could not attach to 0x%lx\n",
	entry.th32OwnerProcessID);
	continue;
	}
	dbg_curr_pid = dbg_curr_process->pid;
	}

	dbg_printf("\nBacktracing for thread 0x%lx in process 0x%lx (%s):\n",
	entry.th32ThreadID, dbg_curr_pid, dbg_curr_process->imageName);
	backtrace_tid(dbg_curr_process, entry.th32ThreadID);
	}
	while (Thread32Next(snapshot, &entry));

	if (dbg_curr_process)
	dbg_curr_process->process_io->close_process(dbg_curr_process, FALSE);
	}
	CloseHandle(snapshot);
	}

	void stack_backtrace(DWORD tid)
	{
	/* backtrace every thread in every process except the debugger itself,
	* invoking via "bt all"
	*/
	if (tid == -1) return backtrace_all();

	if (!dbg_curr_process)
	{
	dbg_printf("You must be attached to a process to run this command.\n");
	return;
	}

	if (tid == dbg_curr_tid)
	{
	backtrace();
	}
	else
	{
	backtrace_tid(dbg_curr_process, tid);
	}
	}