Mega Code Archive
Catch debug information of an application
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Title: Catch debug information of an application
Question: Ever wanted to read the debug information an application sends out?
Answer:
This little codesnippet will ask for the ProcessID (PID) of the application you want to catch debug information from. I did not have time to write some code for it right now, so in the meantime use the taskmanager and get the PID there. :)
Type
TDebugThread = Class(TThread)
Private
{ Private declarations }
Protected
{ Protected declarations }
Procedure Execute; override;
Public
{ Public declarations }
Constructor Create;
Destructor Destroy; override;
End;
TForm1 = class(TForm)
Memo1: TMemo;
TreeView1: TTreeView;
procedure FormCreate(Sender: TObject);
procedure FormDestroy(Sender: TObject);
private
{ Private declarations }
DebugThread : TDebugThread;
public
{ Public declarations }
Procedure BeginCompile(Sender: TObject);
end;
var
Form1: TForm1;
Implementation
Procedure TForm1.FormCreate(Sender: TObject);
Begin
DebugThread := TDebugThread.Create;
End;
procedure TForm1.FormDestroy(Sender: TObject);
Begin
DebugThread.Terminate;
End;
Procedure TDebugThread.Execute;
Var
DebugEvent : _Debug_Event;
ReadLen : DWord;
StrBuffer : pChar;
UniBuffer : WideString;
S : String;
DbgHandle : THandle;
OpenHandle : THandle;
// ProcessNode : TTreeNode;
ThreadNode : TTreeNode;
Begin
S := InputBox('Process', 'Handle', '0');
DbgHandle := StrToIntDef(S, 0);
OpenHandle := OpenProcess(PROCESS_ALL_ACCESS, True, DbgHandle);
IF (DebugActiveProcess(DbgHandle)) Then Form1.Caption := 'Debug ok'
Else Form1.Caption := 'Debug failed';
Form1.TreeView1.Items.Clear;
ThreadNode := Form1.TreeView1.Items.AddChild(NIL, 'Threads');
// ProcessNode := Form1.TreeView1.Items.AddChild(NIL, 'Processes');
While (not Terminated) do
Begin
Sleep(0);
IF (WaitForDebugEvent(DebugEvent, 100)) Then
Begin
IF (not Application.Terminated) Then
Begin
Case DebugEvent.dwDebugEventCode of
OUTPUT_DEBUG_STRING_EVENT : Begin
IF (DebugEvent.DebugString.fUnicode = 0) Then
Begin
StrBuffer := StrAlloc(DebugEvent.DebugString.nDebugStringLength);
ReadProcessMemory(OpenHandle{DebugEvent.dwProcessId}, @DebugEvent.DebugString.lpDebugStringData^, StrBuffer, DebugEvent.DebugString.nDebugStringLength, ReadLen);
Form1.Memo1.Lines.Add(IntToStr(ReadLen)+' - STR - '+StrPas(StrBuffer));
StrDispose(StrBuffer);
End
Else
Begin
SetLength(UniBuffer, DebugEvent.DebugString.nDebugStringLength);
ReadProcessMemory(DebugEvent.dwProcessId, DebugEvent.DebugString.lpDebugStringData, @UniBuffer[1], DebugEvent.DebugString.nDebugStringLength, ReadLen);
UniBuffer := Copy(UniBuffer, 1, ReadLen);
Form1.Memo2.Lines.Add(IntToStr(DebugEvent.DebugString.nDebugStringLength)+' - UNI - '{+UniBuffer});
End;
End;
CREATE_THREAD_DEBUG_EVENT : Begin
Form1.TreeView1.Items.AddChild(ThreadNode, IntToStr(DebugEvent.CreateThread.hThread));
End;
End;
End;
ContinueDebugEvent(DebugEvent.dwProcessId, DebugEvent.dwThreadId, DBG_CONTINUE);
End
Else Sleep(50);
End;
CloseHandle(OpenHandle);
End;
Constructor TDebugThread.Create;
Begin
Inherited Create(False);
FreeOnTerminate := True;
End;
Destructor TDebugThread.Destroy;
Begin
Inherited Destroy;
End;
End.
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