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Sweden-Number/debugger/break.c

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/*
* Debugger break-points handling
*
* Copyright 1994 Martin von Loewis
* Copyright 1995 Alexandre Julliard
*/
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/mman.h>
#include "module.h"
#include "process.h"
#include "task.h"
#include "miscemu.h"
#include "toolhelp.h"
#include "windows.h"
#include "debugger.h"
#include "dosexe.h"
#define INT3 0xcc /* int 3 opcode */
#define MAX_BREAKPOINTS 100
typedef struct
{
DBG_ADDR addr;
BYTE addrlen;
BYTE opcode;
BOOL16 enabled;
WORD skipcount;
BOOL16 in_use;
struct expr * condition;
} BREAKPOINT;
static BREAKPOINT breakpoints[MAX_BREAKPOINTS];
static int next_bp = 1; /* breakpoint 0 is reserved for step-over */
/***********************************************************************
* DEBUG_ChangeOpcode
*
* Change the opcode at segment:addr.
*/
static void DEBUG_SetOpcode( const DBG_ADDR *addr, BYTE op )
{
BYTE *ptr = DBG_ADDR_TO_LIN(addr);
/* There are a couple of problems with this. On Linux prior to
1.1.62, this call fails (ENOACCESS) due to a bug in fs/exec.c.
This code is currently not tested at all on BSD.
How do I get the old protection in order to restore it later on?
*/
if (mprotect((caddr_t)((int)ptr & (~4095)), 4096,
PROT_READ | PROT_WRITE | PROT_EXEC) == -1)
{
perror( "Can't set break point" );
return;
}
*ptr = op;
/* mprotect((caddr_t)(addr->off & ~4095), 4096,
PROT_READ | PROT_EXEC ); */
}
/***********************************************************************
* DEBUG_IsStepOverInstr
*
* Determine if the instruction at CS:EIP is an instruction that
* we need to step over (like a call or a repetitive string move).
*/
static BOOL32 DEBUG_IsStepOverInstr()
{
BYTE *instr = (BYTE *)CTX_SEG_OFF_TO_LIN( &DEBUG_context,
CS_reg(&DEBUG_context),
EIP_reg(&DEBUG_context) );
for (;;)
{
switch(*instr)
{
/* Skip all prefixes */
case 0x2e: /* cs: */
case 0x36: /* ss: */
case 0x3e: /* ds: */
case 0x26: /* es: */
case 0x64: /* fs: */
case 0x65: /* gs: */
case 0x66: /* opcode size prefix */
case 0x67: /* addr size prefix */
case 0xf0: /* lock */
case 0xf2: /* repne */
case 0xf3: /* repe */
instr++;
continue;
/* Handle call instructions */
case 0xcd: /* int <intno> */
case 0xe8: /* call <offset> */
case 0x9a: /* lcall <seg>:<off> */
return TRUE;
case 0xff: /* call <regmodrm> */
return (((instr[1] & 0x38) == 0x10) ||
((instr[1] & 0x38) == 0x18));
/* Handle string instructions */
case 0x6c: /* insb */
case 0x6d: /* insw */
case 0x6e: /* outsb */
case 0x6f: /* outsw */
case 0xa4: /* movsb */
case 0xa5: /* movsw */
case 0xa6: /* cmpsb */
case 0xa7: /* cmpsw */
case 0xaa: /* stosb */
case 0xab: /* stosw */
case 0xac: /* lodsb */
case 0xad: /* lodsw */
case 0xae: /* scasb */
case 0xaf: /* scasw */
return TRUE;
default:
return FALSE;
}
}
}
/***********************************************************************
* DEBUG_IsFctReturn
*
* Determine if the instruction at CS:EIP is an instruction that
* is a function return.
*/
BOOL32 DEBUG_IsFctReturn(void)
{
BYTE *instr = (BYTE *)CTX_SEG_OFF_TO_LIN( &DEBUG_context,
CS_reg(&DEBUG_context),
EIP_reg(&DEBUG_context) );
for (;;)
{
switch(*instr)
{
case 0xc2:
case 0xc3:
return TRUE;
default:
return FALSE;
}
}
}
/***********************************************************************
* DEBUG_SetBreakpoints
*
* Set or remove all the breakpoints.
*/
void DEBUG_SetBreakpoints( BOOL32 set )
{
int i;
for (i = 0; i < MAX_BREAKPOINTS; i++)
{
if (breakpoints[i].in_use && breakpoints[i].enabled)
{
/* Note: we check for read here, because if reading is allowed */
/* writing permission will be forced in DEBUG_SetOpcode. */
if (DEBUG_IsBadReadPtr( &breakpoints[i].addr, 1 ))
{
fprintf( stderr, "Invalid address for breakpoint %d, disabling it\n", i );
breakpoints[i].enabled = FALSE;
}
else DEBUG_SetOpcode( &breakpoints[i].addr,
set ? INT3 : breakpoints[i].opcode );
}
}
}
/***********************************************************************
* DEBUG_FindBreakpoint
*
* Find the breakpoint for a given address. Return the breakpoint
* number or -1 if none.
*/
int DEBUG_FindBreakpoint( const DBG_ADDR *addr )
{
int i;
for (i = 0; i < MAX_BREAKPOINTS; i++)
{
if (breakpoints[i].in_use && breakpoints[i].enabled &&
breakpoints[i].addr.seg == addr->seg &&
breakpoints[i].addr.off == addr->off) return i;
}
return -1;
}
/***********************************************************************
* DEBUG_AddBreakpoint
*
* Add a breakpoint.
*/
void DEBUG_AddBreakpoint( const DBG_ADDR *address )
{
DBG_ADDR addr = *address;
int num;
unsigned int seg2;
BYTE *p;
DBG_FIX_ADDR_SEG( &addr, CS_reg(&DEBUG_context) );
if( addr.type != NULL && addr.type == DEBUG_TypeIntConst )
{
/*
* We know that we have the actual offset stored somewhere
* else in 32-bit space. Grab it, and we
* should be all set.
*/
seg2 = addr.seg;
addr.seg = 0;
addr.off = DEBUG_GetExprValue(&addr, NULL);
addr.seg = seg2;
}
if (!DBG_CHECK_READ_PTR( &addr, 1 )) return;
if (next_bp < MAX_BREAKPOINTS)
num = next_bp++;
else /* try to find an empty slot */
{
for (num = 1; num < MAX_BREAKPOINTS; num++)
if (!breakpoints[num].in_use) break;
if (num >= MAX_BREAKPOINTS)
{
fprintf( stderr, "Too many breakpoints. Please delete some.\n" );
return;
}
}
p = DBG_ADDR_TO_LIN( &addr );
breakpoints[num].addr = addr;
breakpoints[num].addrlen = !addr.seg ? 32 :
(GET_SEL_FLAGS(addr.seg) & LDT_FLAGS_32BIT) ? 32 : 16;
breakpoints[num].opcode = *p;
breakpoints[num].enabled = TRUE;
breakpoints[num].in_use = TRUE;
breakpoints[num].skipcount = 0;
fprintf( stderr, "Breakpoint %d at ", num );
DEBUG_PrintAddress( &breakpoints[num].addr, breakpoints[num].addrlen,
TRUE );
fprintf( stderr, "\n" );
}
/***********************************************************************
* DEBUG_DelBreakpoint
*
* Delete a breakpoint.
*/
void DEBUG_DelBreakpoint( int num )
{
if ((num <= 0) || (num >= next_bp) || !breakpoints[num].in_use)
{
fprintf( stderr, "Invalid breakpoint number %d\n", num );
return;
}
if( breakpoints[num].condition != NULL )
{
DEBUG_FreeExpr(breakpoints[num].condition);
breakpoints[num].condition = NULL;
}
breakpoints[num].enabled = FALSE;
breakpoints[num].in_use = FALSE;
breakpoints[num].skipcount = 0;
}
/***********************************************************************
* DEBUG_EnableBreakpoint
*
* Enable or disable a break point.
*/
void DEBUG_EnableBreakpoint( int num, BOOL32 enable )
{
if ((num <= 0) || (num >= next_bp) || !breakpoints[num].in_use)
{
fprintf( stderr, "Invalid breakpoint number %d\n", num );
return;
}
breakpoints[num].enabled = enable;
breakpoints[num].skipcount = 0;
}
/***********************************************************************
* DEBUG_InfoBreakpoints
*
* Display break points information.
*/
void DEBUG_InfoBreakpoints(void)
{
int i;
fprintf( stderr, "Breakpoints:\n" );
for (i = 1; i < next_bp; i++)
{
if (breakpoints[i].in_use)
{
fprintf( stderr, "%d: %c ", i, breakpoints[i].enabled ? 'y' : 'n');
DEBUG_PrintAddress( &breakpoints[i].addr, breakpoints[i].addrlen,
TRUE);
fprintf( stderr, "\n" );
if( breakpoints[i].condition != NULL )
{
fprintf(stderr, "\t\tstop when ");
DEBUG_DisplayExpr(breakpoints[i].condition);
fprintf(stderr, "\n");
}
}
}
}
/***********************************************************************
* DEBUG_AddTaskEntryBreakpoint
*
* Add a breakpoint at the entry point of the given task
*/
void DEBUG_AddTaskEntryBreakpoint( HTASK16 hTask )
{
TDB *pTask = (TDB *)GlobalLock16( hTask );
NE_MODULE *pModule;
DBG_ADDR addr = { NULL, 0, 0 };
if ( pTask )
{
if (!(pModule = NE_GetPtr( pTask->hModule ))) return;
if (pModule->flags & NE_FFLAGS_LIBMODULE) return; /* Library */
if (pModule->lpDosTask) { /* DOS module */
addr.seg = pModule->lpDosTask->init_cs | ((DWORD)pModule->self << 16);
addr.off = pModule->lpDosTask->init_ip;
fprintf( stderr, "DOS task '%s': ", NE_MODULE_NAME( pModule ) );
DEBUG_AddBreakpoint( &addr );
} else
if (!(pModule->flags & NE_FFLAGS_WIN32)) /* NE module */
{
addr.seg =
GlobalHandleToSel(NE_SEG_TABLE(pModule)[pModule->cs-1].hSeg);
addr.off = pModule->ip;
fprintf( stderr, "Win16 task '%s': ", NE_MODULE_NAME( pModule ) );
DEBUG_AddBreakpoint( &addr );
}
else /* PE module */
{
addr.seg = 0;
addr.off = (DWORD)RVA_PTR( pModule->module32,
OptionalHeader.AddressOfEntryPoint);
fprintf( stderr, "Win32 task '%s': ", NE_MODULE_NAME( pModule ) );
DEBUG_AddBreakpoint( &addr );
}
}
DEBUG_SetBreakpoints( TRUE ); /* Setup breakpoints */
}
/***********************************************************************
* DEBUG_ShouldContinue
*
* Determine if we should continue execution after a SIGTRAP signal when
* executing in the given mode.
*/
BOOL32 DEBUG_ShouldContinue( enum exec_mode mode, int * count )
{
DBG_ADDR addr;
DBG_ADDR cond_addr;
int bpnum;
struct list_id list;
TDB *pTask = (TDB*)GlobalLock16( GetCurrentTask() );
/* If not single-stepping, back up over the int3 instruction */
if (!(EFL_reg(&DEBUG_context) & STEP_FLAG)) EIP_reg(&DEBUG_context)--;
addr.seg = CS_reg(&DEBUG_context);
addr.off = EIP_reg(&DEBUG_context);
if (ISV86(&DEBUG_context)) addr.seg |= (DWORD)(pTask?(pTask->hModule):0)<<16; else
if (IS_SELECTOR_SYSTEM(addr.seg)) addr.seg = 0;
GlobalUnlock16( GetCurrentTask() );
bpnum = DEBUG_FindBreakpoint( &addr );
breakpoints[0].enabled = 0; /* disable the step-over breakpoint */
if ((bpnum != 0) && (bpnum != -1))
{
if( breakpoints[bpnum].condition != NULL )
{
cond_addr = DEBUG_EvalExpr(breakpoints[bpnum].condition);
if( cond_addr.type == NULL )
{
/*
* Something wrong - unable to evaluate this expression.
*/
fprintf(stderr, "Unable to evaluate expression ");
DEBUG_DisplayExpr(breakpoints[bpnum].condition);
fprintf(stderr, "\nTurning off condition\n");
DEBUG_AddBPCondition(bpnum, NULL);
}
else if( ! DEBUG_GetExprValue( &cond_addr, NULL) )
{
return TRUE;
}
}
if( breakpoints[bpnum].skipcount > 0 )
{
breakpoints[bpnum].skipcount--;
if( breakpoints[bpnum].skipcount > 0 )
{
return TRUE;
}
}
fprintf( stderr, "Stopped on breakpoint %d at ", bpnum );
DEBUG_PrintAddress( &breakpoints[bpnum].addr,
breakpoints[bpnum].addrlen, TRUE );
fprintf( stderr, "\n" );
/*
* See if there is a source file for this bp. If so,
* then dig it out and display one line.
*/
DEBUG_FindNearestSymbol( &addr, TRUE, NULL, 0, &list);
if( list.sourcefile != NULL )
{
DEBUG_List(&list, NULL, 0);
}
return FALSE;
}
/*
* If our mode indicates that we are stepping line numbers,
* get the current function, and figure out if we are exactly
* on a line number or not.
*/
if( mode == EXEC_STEP_OVER
|| mode == EXEC_STEP_INSTR )
{
if( DEBUG_CheckLinenoStatus(&addr) == AT_LINENUMBER )
{
(*count)--;
}
}
else if( mode == EXEC_STEPI_OVER
|| mode == EXEC_STEPI_INSTR )
{
(*count)--;
}
if( *count > 0 || mode == EXEC_FINISH )
{
/*
* We still need to execute more instructions.
*/
return TRUE;
}
/*
* If we are about to stop, then print out the source line if we
* have it.
*/
if( (mode != EXEC_CONT && mode != EXEC_FINISH) )
{
DEBUG_FindNearestSymbol( &addr, TRUE, NULL, 0, &list);
if( list.sourcefile != NULL )
{
DEBUG_List(&list, NULL, 0);
}
}
/* If there's no breakpoint and we are not single-stepping, then we */
/* must have encountered an int3 in the Windows program; let's skip it. */
if ((bpnum == -1) && !(EFL_reg(&DEBUG_context) & STEP_FLAG))
EIP_reg(&DEBUG_context)++;
/* no breakpoint, continue if in continuous mode */
return (mode == EXEC_CONT || mode == EXEC_FINISH);
}
/***********************************************************************
* DEBUG_RestartExecution
*
* Set the breakpoints to the correct state to restart execution
* in the given mode.
*/
enum exec_mode DEBUG_RestartExecution( enum exec_mode mode, int count )
{
DBG_ADDR addr;
DBG_ADDR addr2;
int bp;
int delta;
int status;
unsigned int * value;
enum exec_mode ret_mode;
BYTE *instr;
TDB *pTask = (TDB*)GlobalLock16( GetCurrentTask() );
addr.seg = CS_reg(&DEBUG_context);
addr.off = EIP_reg(&DEBUG_context);
if (ISV86(&DEBUG_context)) addr.seg |= (DWORD)(pTask?(pTask->hModule):0)<<16; else
if (IS_SELECTOR_SYSTEM(addr.seg)) addr.seg = 0;
GlobalUnlock16( GetCurrentTask() );
/*
* This is the mode we will be running in after we finish. We would like
* to be able to modify this in certain cases.
*/
ret_mode = mode;
bp = DEBUG_FindBreakpoint( &addr );
if ( bp != -1 && bp != 0)
{
/*
* If we have set a new value, then save it in the BP number.
*/
if( count != 0 && mode == EXEC_CONT )
{
breakpoints[bp].skipcount = count;
}
mode = EXEC_STEPI_INSTR; /* If there's a breakpoint, skip it */
}
else
{
if( mode == EXEC_CONT && count > 1 )
{
fprintf(stderr,"Not stopped at any breakpoint; argument ignored.\n");
}
}
if( mode == EXEC_FINISH && DEBUG_IsFctReturn() )
{
mode = ret_mode = EXEC_STEPI_INSTR;
}
instr = (BYTE *)CTX_SEG_OFF_TO_LIN( &DEBUG_context,
CS_reg(&DEBUG_context),
EIP_reg(&DEBUG_context) );
/*
* See if the function we are stepping into has debug info
* and line numbers. If not, then we step over it instead.
* FIXME - we need to check for things like thunks or trampolines,
* as the actual function may in fact have debug info.
*/
if( *instr == 0xe8 )
{
delta = *(unsigned int*) (instr + 1);
addr2 = addr;
DEBUG_Disasm(&addr2, FALSE);
addr2.off += delta;
status = DEBUG_CheckLinenoStatus(&addr2);
/*
* Anytime we have a trampoline, step over it.
*/
if( ((mode == EXEC_STEP_OVER) || (mode == EXEC_STEPI_OVER))
&& status == FUNC_IS_TRAMPOLINE )
{
#if 0
fprintf(stderr, "Not stepping into trampoline at %x (no lines)\n",
addr2.off);
#endif
mode = EXEC_STEP_OVER_TRAMPOLINE;
}
if( mode == EXEC_STEP_INSTR && status == FUNC_HAS_NO_LINES )
{
#if 0
fprintf(stderr, "Not stepping into function at %x (no lines)\n",
addr2.off);
#endif
mode = EXEC_STEP_OVER;
}
}
if( mode == EXEC_STEP_INSTR )
{
if( DEBUG_CheckLinenoStatus(&addr) == FUNC_HAS_NO_LINES )
{
fprintf(stderr, "Single stepping until exit from function, \n");
fprintf(stderr, "which has no line number information.\n");
ret_mode = mode = EXEC_FINISH;
}
}
switch(mode)
{
case EXEC_CONT: /* Continuous execution */
EFL_reg(&DEBUG_context) &= ~STEP_FLAG;
DEBUG_SetBreakpoints( TRUE );
break;
case EXEC_STEP_OVER_TRAMPOLINE:
/*
* This is the means by which we step over our conversion stubs
* in callfrom*.s and callto*.s. We dig the appropriate address
* off the stack, and we set the breakpoint there instead of the
* address just after the call.
*/
value = (unsigned int *) ESP_reg(&DEBUG_context) + 2;
addr.off = *value;
EFL_reg(&DEBUG_context) &= ~STEP_FLAG;
breakpoints[0].addr = addr;
breakpoints[0].enabled = TRUE;
breakpoints[0].in_use = TRUE;
breakpoints[0].skipcount = 0;
breakpoints[0].opcode = *(BYTE *)DBG_ADDR_TO_LIN( &addr );
DEBUG_SetBreakpoints( TRUE );
break;
case EXEC_FINISH:
case EXEC_STEPI_OVER: /* Stepping over a call */
case EXEC_STEP_OVER: /* Stepping over a call */
if (DEBUG_IsStepOverInstr())
{
EFL_reg(&DEBUG_context) &= ~STEP_FLAG;
DEBUG_Disasm(&addr, FALSE);
breakpoints[0].addr = addr;
breakpoints[0].enabled = TRUE;
breakpoints[0].in_use = TRUE;
breakpoints[0].skipcount = 0;
breakpoints[0].opcode = *(BYTE *)DBG_ADDR_TO_LIN( &addr );
DEBUG_SetBreakpoints( TRUE );
break;
}
/* else fall through to single-stepping */
case EXEC_STEP_INSTR: /* Single-stepping an instruction */
case EXEC_STEPI_INSTR: /* Single-stepping an instruction */
EFL_reg(&DEBUG_context) |= STEP_FLAG;
break;
}
return ret_mode;
}
int
DEBUG_AddBPCondition(int num, struct expr * exp)
{
if ((num <= 0) || (num >= next_bp) || !breakpoints[num].in_use)
{
fprintf( stderr, "Invalid breakpoint number %d\n", num );
return FALSE;
}
if( breakpoints[num].condition != NULL )
{
DEBUG_FreeExpr(breakpoints[num].condition);
breakpoints[num].condition = NULL;
}
if( exp != NULL )
{
breakpoints[num].condition = DEBUG_CloneExpr(exp);
}
return TRUE;
}
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