Windbg学习18(sx和ld)
1.sx
sx* 命令用来控制被调试的程序发生某个异常或特定事件时,调试器要采取的动作
sx 命令显示当前进程的异常列表和所有非异常的事件列表,并且显示调试器遇到每个异常和事件时的行为。
sxr 命令将所有异常和事件过滤器的状态重设为默认值。命令被清除、中断和继续选项被重设为默认值,等等。
sx这个命令的输出信息可以分为三个部分:
第一部分是事件处理与相应处理模式的交互,第二部分是标准的异常交互和处理行为,最后一部分是用户自定义的异常交互和处理行为
以下面为例,我们先输入sxr再输入sx看下默认的处理行为都是怎么样的:
0:000> sxr sx state reset to defaults 0:000> sx ct - Create thread - ignore et - Exit thread - ignore cpr - Create process - ignore epr - Exit process - ignore ld - Load module - output ud - Unload module - ignore ser - System error - ignore ibp - Initial breakpoint - ignore iml - Initial module load - ignore out - Debuggee output - output av - Access violation - break - not handled asrt - Assertion failure - break - not handled aph - Application hang - break - not handled bpe - Break instruction exception - break bpec - Break instruction exception continue - handled eh - C++ EH exception - second-chance break - not handled clr - CLR exception - second-chance break - not handled clrn - CLR notification exception - second-chance break - handled cce - Control-Break exception - break cc - Control-Break exception continue - handled cce - Control-C exception - break cc - Control-C exception continue - handled dm - Data misaligned - break - not handled dbce - Debugger command exception - ignore - handled gp - Guard page violation - break - not handled ii - Illegal instruction - second-chance break - not handled ip - In-page I/O error - break - not handled dz - Integer divide-by-zero - break - not handled iov - Integer overflow - break - not handled ch - Invalid handle - break hc - Invalid handle continue - not handled lsq - Invalid lock sequence - break - not handled isc - Invalid system call - break - not handled 3c - Port disconnected - second-chance break - not handled svh - Service hang - break - not handled sse - Single step exception - break ssec - Single step exception continue - handled sbo - Stack buffer overflow - break - not handled sov - Stack overflow - break - not handled vs - Verifier stop - break - not handled vcpp - Visual C++ exception - ignore - handled wkd - Wake debugger - break - not handled wob - WOW64 breakpoint - break - handled wos - WOW64 single step exception - break - handled * - Other exception - second-chance break - not handled
随便找个出来ld - Load module - output,说明在加载模块时的行为是输出,OK,我们把它断掉:
sxe | Break (Enabled) |
当发生该异常时,在任何错误处理器被激活之前目标立即中断到调试器中。这种处理类型称为第一次处理机会。 |
sxd | Second chance break (Disabled) |
发生该类异常时,调试器不会在第一次处理机会时中断(虽然会显示信息)。如果其他错误处理器没有处理掉该异常,执行会停止下来并中断到调试器。这种处理类型称为第二次处理机会。 |
sxn | Output (Notify) |
当该异常发生时,目标程序不中断到调试器中。但是,会通过一条消息提示发生了异常。 |
sxi | Ignore | 异常发生时,目标程序不中断到调试器,并且不会显示信息。 |
使用sxe ld试试
:000> sxe ld 0:000> sx ct - Create thread - ignore et - Exit thread - ignore cpr - Create process - ignore epr - Exit process - ignore ld - Load module - break
再次调用sx查看,我们发现现在变成了ld - Load module - break,处理行为变成了break,运行试试
0:000> g ModLoad: 73fa0000 7400b000 C:\WINDOWS\system32\USP10.dll eax=77ef23d4 ebx=00000000 ecx=77ef7c79 edx=62c25200 esi=00000000 edi=00000000 eip=7c92e514 esp=0012e8c0 ebp=0012e9b4 iopl=0 nv up ei ng nz ac pe nc cs=001b ss=0023 ds=0023 es=0023 fs=003b gs=0000 efl=00000296 ntdll!KiFastSystemCallRet: 7c92e514 c3 ret 0:000> kb ChildEBP RetAddr Args to Child 0012e8bc 7c92d52a 7c93adfb 000007d0 ffffffff ntdll!KiFastSystemCallRet 0012e8c0 7c93adfb 000007d0 ffffffff 0012e998 ntdll!NtMapViewOfSection+0xc 0012e9b4 7c93c880 001531a0 7ffdfc00 00000000 ntdll!LdrpMapDll+0x330 0012ec14 7c9446f2 001531a0 62c202d4 62c20000 ntdll!LdrpLoadImportModule+0x174 0012ec58 7c94469b 7ffd9000 001531a0 00253128 ntdll!LdrpHandleOneNewFormatImportDescriptor+0x53 0012ec78 7c9447d5 7ffd9000 001531a0 00253128 ntdll!LdrpHandleNewFormatImportDescriptors+0x20 0012ecf4 7c936227 001531a0 00253128 c0150008 ntdll!LdrpWalkImportDescriptor+0x19e 0012efa4 7c93643d 00000000 001531a0 0012f298 ntdll!LdrpLoadDll+0x24e 0012f24c 7c801bbd 001531a0 0012f298 0012f278 ntdll!LdrLoadDll+0x230 0012f2b4 7c80aefc 77ef1a1c 00000000 00000000 kernel32!LoadLibraryExW+0x18e 0012f2c8 77f1da06 77ef1a1c 00000000 7ffdf000 kernel32!LoadLibraryW+0x11 0012f2f0 77f14361 0000001f 00000000 77d712a0 GDI32!GdiInitializeLanguagePack+0x15 0012f304 77d1a03d 00000000 00000000 7c946102 GDI32!GdiProcessSetup+0x11d 0012f444 77d1a143 7c92e473 0012f458 00000000 USER32!ClientThreadSetup+0x33 0012f448 7c92e473 0012f458 00000000 77ef67c4 USER32!__ClientThreadSetup+0x5 0012f454 77ef67c4 77ef6553 0012f5a8 0012f9f0 ntdll!KiUserCallbackDispatcher+0x13 0012f464 77d1b473 77d10000 00000001 0012fd30 GDI32!NtGdiInit+0xc 0012f9f0 7c92118a 77d10000 00000001 0012fd30 USER32!_UserClientDllInitialize+0x315 0012fa10 7c93b5d2 77d1b217 77d10000 00000001 ntdll!LdrpCallInitRoutine+0x14 0012fb18 7c93fbdc 0012fd30 7ffdf000 7ffd9000 ntdll!LdrpRunInitializeRoutines+0x344 0:000> du 77ef1a1c 77ef1a1c "LPK.DLL"
果然断下来了,断在加载LPK.dll模块时,那么如果我们只想让它在加载SkinHgy.dll时断下来怎么办呢?需要介绍下ld了
2.ld
ld(load symbols)命令加载指定模块的符号并刷新所有模块信息。
0:000> lm start end module name 00400000 00b89000 Simple1Demo (deferred) 7c920000 7c9b6000 ntdll (pdb symbols) c:\mysymbol\ntdll.pdb\CEFC0863B1F84130A11E0F54180CD21A2\ntdll.pdb 0:000> ld Simple1Demo *** WARNING: Unable to verify checksum for Simple1Demo.exe Symbols loaded for Simple1Demo 0:000> lm start end module name 00400000 00b89000 Simple1Demo C (private pdb symbols) D:\project\代码\新控件库\SkinHgy\Debug\Simple1Demo.pdb 7c920000 7c9b6000 ntdll (pdb symbols) c:\mysymbol\ntdll.pdb\CEFC0863B1F84130A11E0F54180CD21A2\ntdll.pdb
再加载次试试:
0:000> ld Simple1Demo Symbols already loaded for Simple1Demo
提示已加载,看来还是.reload好用啊。
0:000> sx ct - Create thread - ignore et - Exit thread - ignore cpr - Create process - ignore epr - Exit process - ignore ld - Load module - break ud - Unload module - ignore ser - System error - ignore ibp - Initial breakpoint - ignore iml - Initial module load - ignore out - Debuggee output - output av - Access violation - break - not handled asrt - Assertion failure - break - not handled aph - Application hang - break - not handled bpe - Break instruction exception - break bpec - Break instruction exception continue - handled eh - C++ EH exception - second-chance break - not handled clr - CLR exception - second-chance break - not handled clrn - CLR notification exception - second-chance break - handled cce - Control-Break exception - break cc - Control-Break exception continue - handled cce - Control-C exception - break cc - Control-C exception continue - handled dm - Data misaligned - break - not handled dbce - Debugger command exception - ignore - handled gp - Guard page violation - break - not handled ii - Illegal instruction - second-chance break - not handled ip - In-page I/O error - break - not handled dz - Integer divide-by-zero - break - not handled iov - Integer overflow - break - not handled ch - Invalid handle - break hc - Invalid handle continue - not handled lsq - Invalid lock sequence - break - not handled isc - Invalid system call - break - not handled 3c - Port disconnected - second-chance break - not handled svh - Service hang - break - not handled sse - Single step exception - break ssec - Single step exception continue - handled sbo - Stack buffer overflow - break - not handled sov - Stack overflow - break - not handled vs - Verifier stop - break - not handled vcpp - Visual C++ exception - ignore - handled wkd - Wake debugger - break - not handled wob - WOW64 breakpoint - break - handled wos - WOW64 single step exception - break - handled * - Other exception - second-chance break - not handled 0:000> sex ld skinhgy.dll Couldn't resolve error at 'ex ' 0:000> sxe ld skinhgy.dll 0:000> sx ct - Create thread - ignore et - Exit thread - ignore cpr - Create process - ignore epr - Exit process - ignore ld - Load module - break (only break for skinhgy.dll) ud - Unload module - ignore ser - System error - ignore ibp - Initial breakpoint - ignore iml - Initial module load - ignore out - Debuggee output - output av - Access violation - break - not handled asrt - Assertion failure - break - not handled aph - Application hang - break - not handled bpe - Break instruction exception - break bpec - Break instruction exception continue - handled eh - C++ EH exception - second-chance break - not handled clr - CLR exception - second-chance break - not handled clrn - CLR notification exception - second-chance break - handled cce - Control-Break exception - break cc - Control-Break exception continue - handled cce - Control-C exception - break cc - Control-C exception continue - handled dm - Data misaligned - break - not handled dbce - Debugger command exception - ignore - handled gp - Guard page violation - break - not handled ii - Illegal instruction - second-chance break - not handled ip - In-page I/O error - break - not handled dz - Integer divide-by-zero - break - not handled iov - Integer overflow - break - not handled ch - Invalid handle - break hc - Invalid handle continue - not handled lsq - Invalid lock sequence - break - not handled isc - Invalid system call - break - not handled 3c - Port disconnected - second-chance break - not handled svh - Service hang - break - not handled sse - Single step exception - break ssec - Single step exception continue - handled sbo - Stack buffer overflow - break - not handled sov - Stack overflow - break - not handled vs - Verifier stop - break - not handled vcpp - Visual C++ exception - ignore - handled wkd - Wake debugger - break - not handled wob - WOW64 breakpoint - break - handled wos - WOW64 single step exception - break - handled * - Other exception - second-chance break - not handled
我们已经restart了,但ld的状态还没有变,所以WinDBG会自动把一些东西记录到工作空间(Workspace)里,因为工作空间是隐式管理的,所以容易让初用WinDBG的人摸不着头脑,像MJ说的那样操作一下,并且保存到工作空间中(结束调试时,WinDBG询问要不要保存工作空间时选YES),或者干脆删除工作空间就可以了,当然也可以写成
0:000> sxe ld skin* 0:000> sx ct - Create thread - ignore et - Exit thread - ignore cpr - Create process - ignore epr - Exit process - ignore ld - Load module - break (only break for skin*) ud - Unload module - ignore ser - System error - ignore ibp - Initial breakpoint - ignore iml - Initial module load - ignore out - Debuggee output - output av - Access violation - break - not handled asrt - Assertion failure - break - not handled aph - Application hang - break - not handled bpe - Break instruction exception - break bpec - Break instruction exception continue - handled eh - C++ EH exception - second-chance break - not handled clr - CLR exception - second-chance break - not handled clrn - CLR notification exception - second-chance break - handled cce - Control-Break exception - break cc - Control-Break exception continue - handled cce - Control-C exception - break cc - Control-C exception continue - handled dm - Data misaligned - break - not handled dbce - Debugger command exception - ignore - handled gp - Guard page violation - break - not handled ii - Illegal instruction - second-chance break - not handled ip - In-page I/O error - break - not handled dz - Integer divide-by-zero - break - not handled iov - Integer overflow - break - not handled ch - Invalid handle - break hc - Invalid handle continue - not handled lsq - Invalid lock sequence - break - not handled isc - Invalid system call - break - not handled 3c - Port disconnected - second-chance break - not handled svh - Service hang - break - not handled sse - Single step exception - break ssec - Single step exception continue - handled sbo - Stack buffer overflow - break - not handled sov - Stack overflow - break - not handled vs - Verifier stop - break - not handled vcpp - Visual C++ exception - ignore - handled wkd - Wake debugger - break - not handled wob - WOW64 breakpoint - break - handled wos - WOW64 single step exception - break - handled * - Other exception - second-chance break - not handled
这样所有的Skin*模块都会触发断点
sx{e|d|i|n} [-c "Cmd1"] [-c2 "Cmd2"] [-h] {Exception|Event|*}
0:000> sxe -c".echo 'skinhgy.dll loading'" ld:skinhgy.dll 0:000> sx ct - Create thread - ignore et - Exit thread - ignore cpr - Create process - ignore epr - Exit process - break ld - Load module - break Command: ".echo 'skinhgy.dll loading'" (only break for skinhgy.dll) ud - Unload module - ignore
运行后:
0:000> g ModLoad: 10000000 10301000 D:\project\代码\新控件库\SkinHgy\Debug\SkinHgy.dll 'skinhgy.dll loading'
这里介绍种GUI使用的方法:
Debug--Event Filters打开:
我们看到我们先前加载的SkinHgy.dll都在,事件(-c和-c2)对应Commands按钮来修改,中断状态可以通过"Execution"来修改,还可以通过Add和Remove来增加或删除异常码.
至于
Enabled对应Break
Disabled对应Second chance break
sxe | Handled | 执行返回时,事件被标识为已处理。 |
sxd, sxn, sxi |
Not Handled | 执行返回时,事件被标识为未处理。 |
windbg帮助上写得很清楚了.
补充点:
Sxe av //当access violation发生就停止
Sxd eh//当C++ exception发生,调试器什么都不做
这两个很有用,今天在调程序时发现内存访问一直被断,用sxi av就行了,不过为什么windbg帮助文档查不到av