Breakpad 使用方法理解文档

Breakpad 使用方法理解文档.

只需要在任何异常前正常创建一个ExceptionHandler类的成员函数,就可以完成异常的捕捉及dump.

在创建ExceptionHandler时,第一参数为宽字符表示的dump存储路径,第二参数为dump前客户需要运行的程序,程序原型应该为

 

bool (*FilterCallback)(void* context,

EXCEPTION_POINTERS* exinfo,

MDRawAssertionInfo* assertion);

 

程序返回false将不产生dump,返回true才正常dump.

 

第三参数为客户Dump后需要运行的程序,程序原型为:

 

bool (*MinidumpCallback)(const wchar_t* dump_path,

                                   const wchar_t* minidump_id,

                                   void* context,

                                   EXCEPTION_POINTERS* exinfo,

                                   MDRawAssertionInfo* assertion,

                                   bool succeeded);

 

程序返回true表示异常全部被控制,程序正常运行,返回false,程序仍然保留异常,以方便交给其他程序处理,比如各平台的原生异常处理系统.

 

 

HandlerType:确定需要控制的异常类型,HANDLER_ALL时,控制所有类型的异常.

 

 

ExceptionHandler有两个版本的构造函数:

  ExceptionHandler(const wstring& dump_path,

                   FilterCallback filter,

                   MinidumpCallback callback,

                   void* callback_context,

                   int handler_types);

 

  ExceptionHandler(const wstring& dump_path,

                   FilterCallback filter,

                   MinidumpCallback callback,

                   void* callback_context,

                   int handler_types,

                   MINIDUMP_TYPE dump_type,

                   const wchar_t* pipe_name,

                   const CustomClientInfo* custom_info);

 

 

dump_path()用来返回dump的路径.

Set_dump_path(const wstring &dump_path)用来设置路径.

 

WriteMinidump()

WriteMinidump(const wstring &dump_path,

                            MinidumpCallback callback, void* callback_context);立即写dump文件.

 

WriteMinidumpForException(EXCEPTION_POINTERS* exinfo)用用户提供的异常信息立即写dump文件.

 

get_requesting_thread_id()得到出现异常或者调用WriteMinidump()函数的线程ＩＤ．

 

 

bool ExceptionHandler::WriteMinidumpWithException(

    DWORD requesting_thread_id,

    EXCEPTION_POINTERS* exinfo,

MDRawAssertionInfo* assertion)

为最主要的函数,具体的写下Dump文件.

 

这个结构很明显是用来保存异常信息的

typedef struct _EXCEPTION_RECORD {

    DWORD    ExceptionCode;

    DWORD ExceptionFlags;

    struct _EXCEPTION_RECORD *ExceptionRecord;

    PVOID ExceptionAddress;

    DWORD NumberParameters;

    ULONG_PTR ExceptionInformation[EXCEPTION_MAXIMUM_PARAMETERS];

    } EXCEPTION_RECORD;

 

typedef EXCEPTION_RECORD *PEXCEPTION_RECORD;

 

 

typedef struct _CONTEXT {

 

    //

    // The flags values within this flag control the contents of

    // a CONTEXT record.

    //

    // If the context record is used as an input parameter, then

    // for each portion of the context record controlled by a flag

    // whose value is set, it is assumed that that portion of the

    // context record contains valid context. If the context record

    // is being used to modify a threads context, then only that

    // portion of the threads context will be modified.

    //

    // If the context record is used as an IN OUT parameter to capture

    // the context of a thread, then only those portions of the thread's

    // context corresponding to set flags will be returned.

    //

    // The context record is never used as an OUT only parameter.

    //

 

    DWORD ContextFlags;

 

    //

    // This section is specified/returned if CONTEXT_DEBUG_REGISTERS is

    // set in ContextFlags.  Note that CONTEXT_DEBUG_REGISTERS is NOT

    // included in CONTEXT_FULL.

    //

 

    DWORD   Dr0;

    DWORD   Dr1;

    DWORD   Dr2;

    DWORD   Dr3;

    DWORD   Dr6;

    DWORD   Dr7;

 

    //

    // This section is specified/returned if the

    // ContextFlags word contians the flag CONTEXT_FLOATING_POINT.

    //

 

    FLOATING_SAVE_AREA FloatSave;

 

    //

    // This section is specified/returned if the

    // ContextFlags word contians the flag CONTEXT_SEGMENTS.

    //

 

    DWORD   SegGs;

    DWORD   SegFs;

    DWORD   SegEs;

    DWORD   SegDs;

 

    //

    // This section is specified/returned if the

    // ContextFlags word contians the flag CONTEXT_INTEGER.

    //

 

    DWORD   Edi;

    DWORD   Esi;

    DWORD   Ebx;

    DWORD   Edx;

    DWORD   Ecx;

    DWORD   Eax;

 

    //

    // This section is specified/returned if the

    // ContextFlags word contians the flag CONTEXT_CONTROL.

    //

 

    DWORD   Ebp;

    DWORD   Eip;

    DWORD   SegCs;              // MUST BE SANITIZED

    DWORD   EFlags;             // MUST BE SANITIZED

    DWORD   Esp;

    DWORD   SegSs;

 

    //

    // This section is specified/returned if the ContextFlags word

    // contains the flag CONTEXT_EXTENDED_REGISTERS.

    // The format and contexts are processor specific

    //

 

    BYTE    ExtendedRegisters[MAXIMUM_SUPPORTED_EXTENSION];

 

} CONTEXT;

 

typedef CONTEXT *PCONTEXT;

 

 

 

typedef struct _EXCEPTION_POINTERS {

    PEXCEPTION_RECORD ExceptionRecord;

    PCONTEXT ContextRecord;

} EXCEPTION_POINTERS, *PEXCEPTION_POINTERS;

 

 

typedef struct {

  /* expression, function, and file are 0-terminated UTF-16 strings.  They

   * may be truncated if necessary, but should always be 0-terminated when

   * written to a file.

   * Fixed-length strings are used because MiniDumpWriteDump doesn't offer

   * a way for user streams to point to arbitrary RVAs for strings. */

  u_int16_t expression[128];  /* Assertion that failed... */

  u_int16_t function[128];    /* ...within this function... */

  u_int16_t file[128];        /* ...in this file... */

  u_int32_t line;             /* ...at this line. */

  u_int32_t type;

} MDRawAssertionInfo;

 

 

 

实现上:当FilterCallback(即ExceptionHandler构造函数的第二参数)不为空的时候,首先用WriteMinidumpWithException函数的原参数直接调用FilterCallback,(参数类型一致),完成用户在调用Dump先需要做的工作.

然后通过IsOutOfProcess（）成员函数判断是否此时是Exception_handler自身来进行dump,详细内容,参看 <Breakpad在进程中完成dump的流程文字描述>

当IsOutOfProcess()返回真的时候,应该表示此时处理是在进程外发生的,也就是利用crash_generation的client,server的机制完成,不影响原进程的运行.

此时调用CrashGenerationClient类型的成员变量的RequestDump函数完成dump.

 

当返回假的时候,此时先判断是否从dbghelp.dll中正确的import了MiniDumpWriteDump函数,然后创建了一个新的可写的文件.

当创建成功后,ExceptionHander加入异常信息到user_streams,然后调用minidump_write_dump_(实际就是dbghelp.dll中的MiniDumpWriteDump函数)完成dump.

 

主要的信息都在WriteMinidumpWithException函数的第二参数及第三参数里面.从注释上看,这些信息属于breakpad自己新增加的附加信息,但是增加这些信息对以前的dump文件正常使用没有影响,这些信息来自出现纯虚函数调用和无效参数调用时,breakpad自定义的用户函数中添加的信息.

 

    _set_invalid_parameter_handler(ExceptionHandler::HandleInvalidParameter);

#endif  // _MSC_VER >= 1400

_set_purecall_handler(ExceptionHandler::HandlePureVirtualCall);

 

即, HandleInvalidParameter, HandlePureVirtualCall中添加的信息.

此信息类型为MDRawAssertionInfo,在HandlePureVirtualCall函数调用时,仅仅是设定异常类型为HandlePureVirtualCall,当出现无效参数调用时,增加的内容较多:

  _snwprintf_s(reinterpret_cast<wchar_t*>(assertion.expression),

               sizeof(assertion.expression) /, sizeof(assertion.expression[0]),

               _TRUNCATE, L"%s", expression);

  _snwprintf_s(reinterpret_cast<wchar_t*>(assertion.function),

               sizeof(assertion.function) / sizeof(assertion.function[0]),

               _TRUNCATE, L"%s", function);

  _snwprintf_s(reinterpret_cast<wchar_t*>(assertion.file),

               sizeof(assertion.file) / sizeof(assertion.file[0]),

               _TRUNCATE, L"%s", file);

  assertion.line = line;

  assertion.type = MD_ASSERTION_INFO_TYPE_INVALID_PARAMETER;

 

分别为调用无效参数的表达式,函数名,文件名,行号,最后设定异常类型为

MD_ASSERTION_INFO_TYPE_INVALID_PARAMETE.

 

最后关闭文件,再调用callback_函数,也就是ExceptionHandler构造函数的第三参数.

 

其他主要内容在 <Breakpad在进程中完成dump的流程文字描述>描述.