如何使用 dbgen.h 实现命令的文本自动完成？

如何解决如何使用 dbgen.h 实现命令的文本自动完成？

我正在为 windbg 开发一个前端，它使用了文档完善的 dbgeng.h API。但是，有些功能我不知道如何实现，例如选项卡自动完成。我相信我需要的是以下 API： IDebugAdvanced3::Request

DEBUG_REQUEST_GET_TEXT_COMPLETIONS_ANSI（未记录）

在定义这些结构的 dbgeng.h 中还有一些注释：

typedef struct _DEBUG_GET_TEXT_COMPLETIONS_IN
{
    ULONG Flags;
    ULONG MatchCountLimit;
    ULONG64 Reserved[3];
    // Input text string follows.
} DEBUG_GET_TEXT_COMPLETIONS_IN,*PDEBUG_GET_TEXT_COMPLETIONS_IN;

typedef struct _DEBUG_GET_TEXT_COMPLETIONS_OUT
{
    ULONG Flags;
    // Char index in input string where completions start.
    ULONG ReplaceIndex;
    ULONG MatchCount;
    ULONG Reserved1;
    ULONG64 Reserved2[2];
    // Completions follow.
    // Completion data is zero-terminated strings ended
    // by a final zero double-terminator.
} DEBUG_GET_TEXT_COMPLETIONS_OUT,*PDEBUG_GET_TEXT_COMPLETIONS_OUT;

我不明白我应该如何使用这个 API。

编辑：我按照评论中的建议尝试了以下操作：

struct in_wrap
{
    DEBUG_GET_TEXT_COMPLETIONS_IN in;
    char src[4];
};
in_wrap wrp;

DEBUG_GET_TEXT_COMPLETIONS_IN in;
in.Flags = DEBUG_GET_TEXT_COMPLETIONS_NO_SYMBOLS;
in.MatchCountLimit = 5;

wrp.in = in;
strcpy(wrp.src,".ec"); // I'm expecting to receive ".echo" back.

DEBUG_GET_TEXT_COMPLETIONS_OUT out = {};
ULONG outsize = 0;

hr = advanced->Request(DEBUG_REQUEST_GET_TEXT_COMPLETIONS_ANSI,(void *)&wrp,sizeof(in_wrap),(void *)&out,sizeof(DEBUG_GET_TEXT_COMPLETIONS_OUT),&outsize);

返回 E_INVALIDARGS。

解决方法

部分输入是通配符，因此您的输入后需要一个星号，例如“.db*”
输出需要两次迭代，其中一次用于获取 S_FALSE 的大小和可用的完成大小
第二个在 OUT 之后分配的内存作为类型定义的结构作为 IN

下面的代码在 OUT 中有一个固定大小的缓冲区作为 poc
如果您只通过 OUT 而没有缓冲区，您应该收到一个 S_FALSE(01) 作为 HRESULT

opsize 必须指示完成字符所需的内存大小

代码如下

#include <engextcpp.cpp>
typedef struct _AUTOCOMPIN {
    DEBUG_GET_TEXT_COMPLETIONS_IN auin;
    char instr[8];
} Autocompin,*PAutocompin;
typedef struct _AUTOCOMPOUT {
    DEBUG_GET_TEXT_COMPLETIONS_OUT auout;
    char ostr[0x1000];
} Autocompout,*Pautocompout;
class EXT_CLASS : public ExtExtension    {
public:
    EXT_COMMAND_METHOD(autocomp);
};
EXT_DECLARE_GLOBALS();
EXT_COMMAND(autocomp,"","")    {
    Autocompin ibuff = {0};
    Autocompout obuff = {0};
    ULONG opsize = 0;
    HRESULT hr = E_FAIL;
    strcpy_s(ibuff.instr,".d*");
    hr = m_Advanced2->Request(
        DEBUG_REQUEST_GET_TEXT_COMPLETIONS_ANSI,&ibuff,sizeof(ibuff),&obuff,sizeof(obuff),&opsize);
    Out("hr = %x opsize = %x IDebugAdvancedCheckPointer = %p\n",hr,opsize,m_Advanced2);
    for (ULONG i = 0; i < opsize; i++) {
        Out("%c ",obuff.ostr[i]);
    }
}

编译并链接

:\>cl
Microsoft (R) C/C++ Optimizing Compiler Version 19.16.27045 for x64
Copyright (C) Microsoft Corporation.  All rights reserved.

usage: cl [ option... ] filename... [ /link linkoption... ]

:\>type complink.bat (must be in one line )
cl /LD /nologo /W4 /Od  /Zi /EHsc /I"C:\Program Files (x86)\Windows Kits\10\Debuggers\inc" %1.cpp   
/link /EXPORT:DebugExtensionInitialize /Export:%1 /Export:help /RELEASE
:\>

编译执行

:\>complink.bat autocomp

:\>cl /LD /nologo /W4 /Od  /Zi /EHsc /I"C:\Program Files (x86)\Windows Kits\10\Debuggers\inc" autocomp.cpp /link /EXPORT:DebugExtensionInitialize /Export:autocomp /Export:help /RELEASE
autocomp.cpp
C:\Program Files (x86)\Windows Kits\10\Debuggers\inc\engextcpp.cpp(1849): warning C4245: 'argument': conversion from 'int' to 'ULONG64',signed/unsigned mismatch
   Creating library autocomp.lib and object autocomp.exp

:\>cdb -c ".load .\autocomp;!autocomp;q" cdb

Microsoft (R) Windows Debugger Version 10.0.17763.132 AMD64
0:000> cdb: Reading initial command '.load .\autocomp;!autocomp;q'
hr = 0 opsize = 8c IDebugAdvancedCheckPointer = 00000057edfface0
d b g d b g  
d e b u g _ s w _ w o w  
d e t a c h  
d m l _ f i l e  
d m l _ f l o w  
d m l _ s t a r t  
d o  d r i v e r s  
d u m p  
d v a l l o c  
d v f r e e  
d i s a b l e p a c k a g e d e b u g                                    
quit: