断点部分
- 命令帮助
.hh help_command
- 设置断点
bp / bm(breakpoint set by symbol)
条件断点使用".if(){} .else{}"
如果说需要对[ebp-4]大于40
的时候停止,那么条件断点应该设置为:
//command intro:
// poi a == [a]
// {} //means bp hit.
// gc Go Continue 错误-update5.17 ×
//gc (Go from Conditional Breakpoint) √
bp bp_addr ".if(poi (ebp-4) > 28h) {} .else {gc}"
如果源码为:
#include <stdio.h>
void loop(int a,int b)
{
int i;
for ( i = 0; ;i++)
{
if (i == 100000)
{
break;
}
printf("%d\n",i);
}
}
int main(int argc,char **argv)
{
int a = 1;
int b = 0;
int sum = a+b;
loop(a,b);
return 0;
}
在windbg下条件断点
0:000> bp 401055 ".if(poi (ebp-4) >1025){} .else {gc}"
breakpoint 0 redefined
0:000> g
eax=00001026 ebx=7ffd7000 ecx=00424a60 edx=00424a60 esi=00baf770 edi=0012ff18
eip=00401055 esp=0012fec8 ebp=0012ff18 iopl=0 nv up ei ng nz na po cy
cs=001b ss=0023 ds=0023 es=0023 fs=003b gs=0000 efl=00000283
windbg_test!loop+0x35:
00401055 8b4dfc mov ecx,dword ptr [ebp-4] ss:0023:0012ff14=00001026
注意:1025
是十六进制,不是十进制。poi
的优先级比-
高,所以应该加括号。
0:000> dd ebp-4 l1
0012ff14 00001026
0:000> dd ebp l1
0012ff18 0012ff80
0:000> dd 12ff80-4 l1
0012ff7c 00000001
0:000> dd poi ebp - 4 l1
0012ff7c 00000001
0:000> dd poi (ebp-4) l1
00001026 ????????
------------------
result:
ebp = 12ff18
[ebp-4]=poi(ebp-4) =[12ff14]=1026h
poi ebp -4 = (poi ebp) -4 = [ebp]-4 =[12ff18]- 4 = 12ff80 - 4 = 12ff7c
函数调用栈回朔
0:000> k
ChildEBP RetAddr
0012ff18 004010cc windbg_test!loop+0x35 [C:\VC6\MyProjects\windbg_test\example.c @ 12]
0012ff80 004012a9 windbg_test!main+0x3c [C:\VC6\MyProjects\windbg_test\example.c @ 21]
0012ffc0 7c817067 windbg_test!mainCRTStartup+0xe9 [crt0.c @ 206]
0012fff0 00000000 kernel32!BaseProcessStart+0x23