How to break code on a click event? - windows

I have this application that I need to disassemble. I don't have a clue on how to stop the running code on the desired location, so I decided my best guess would be breaking upon a button click. But how do I capture button clicks? I know it has probably something to do with the Windows functions such as CallNextHookEx. I'm using IDA PRO to disassembly.

IDA PRO is used mostly as disassembler, for static analysis purposes. I'd suggest you to use Ollydbg (or some other debugger, if you want to) because it will suit better to debugging purposes.
I don't know if you can set a breakpoint on an API like that.
But you can do this:
Load the application in olly, or attach to it.
Generate the event by clicking on anything.
Stop the application from ollydbg(F12)
Use C(k)all stack(ALT+K)
You will see a few calls to functions, one of them is doing what you need. But you may need to go to upper calls to see the whole loop. So you will just try which one it is. There will be a loop in one of them.That loop will have conditional jumps and generate events, load forms, fill the app etc. And when you place a breakpoint on the right jump there, it will stop at each mouse click.
When I'm debugging apps, most of the times I find myself on a breakpoint like this, and I see from the beginning how the application is filling an empty form(it takes so long.)

Related

Implementing a Custom Cocoa Event Tracking Loop

I'm working on a custom cross platform UI library that needs a synchronous "ShowPopup" method that shows a popup, runs an event loop until it's finished and automatically cancels when clicking outside the popup or pressing escape. Keyboard, mouse and scroll wheel events need to be dispatched to the popup but other events (paint, draw, timers etc...) need to be dispatched to their regular targets while the loop runs.
Edit: for clarification, by popup, I mean this kind of menu style popup window, not an alert/dialog etc...
On Windows I've implemented this fairly simply by calling GetMessage/DispatchMessage and filtering and dispatching messages as appropriate. Works fine.
I've much less experience with Cocoa/OS X however and finding the whole event loop/dispatch paradigm a bit confusing. I've seen the following article which explains how to implement a mouse tracking loop which is very similar to what I need:
http://stpeterandpaul.ca/tiger/documentation/Cocoa/Conceptual/EventOverview/HandlingMouseEvents/chapter_5_section_4.html
but... there's some things about this that concern me.
The linked article states: "the application’s main thread is unable to process any other requests during an event-tracking loop and timers might not fire". Might not? Why not, when not, how to make sure they do?
The docs for nextEventMatchingMask:untilDate:inMode:dequeue: states "events that do not match one of the specified event types are left in the queue.". That seems a little odd. Does this mean that if an event loop only asks for mouse events then any pressed keys will be processed once the loop finishes? That'd be weird.
Is it possible to peek at a message in the event queue without removing it. eg: the Windows version of my library uses this to close the popup when it's clicked outside, but leaves the click event in the queue so that clicking outside the popup on a another button doesn't require a second click.
I've read and re-read about run loop modes but still don't really get it. A good explanation of what these are for would be great.
Are there any other good examples of implementing an event loop for a popup. Even better would be pseudo-code for what the built in NSApplication run loop does.
Another way of putting all this... what's the Cocoa equivalent of Windows' PeekMessage(..., PM_REMOVE), PeekMessage(..., PM_NOREMOVE) and DispatchMessage().
Any help greatly appreciated.
What exactly is a "popup" as you're using the term? That term means different things in different GUI APIs. Is it just a modal dialog window?
Update for edits to question:
It seems you just want to implement a custom menu. Apple provides a sample project, CustomMenus, which illustrates that technique. It's a companion to one of the WWDC 2010 session videos, Session 145, "Key Event Handling in Cocoa Applications".
Depending on exactly what you need to achieve, you might want to use an NSAlert. Alternatively, you can use a custom window and just run it modally using the -runModalForWindow: method of NSApplication.
To meet your requirement of ending the modal session when the user clicks outside of the window, you could use a local event monitor. There's even an example of just such functionality in the (modern, current) Cocoa Event Handling Guide: Monitoring Events.
All of that said, here are (hopefully no longer relevant) answers to your specific questions:
The linked article states: "the application’s main thread is unable to process any other requests during an event-tracking loop and
timers might not fire". Might not? Why not, when not, how to make
sure they do?
Because timers are scheduled in a particular run loop mode or set of modes. See the answer to question 4, below. You would typically use the event-tracking mode when running an event-tracking loop, so timers which are not scheduled in that mode will not run.
You could use the default mode for your event-tracking loop, but it really isn't a good idea. It might cause unexpected re-entrancy.
Assuming your pop-up is similar to a modal window, you should probably use NSModalPanelRunLoopMode.
The docs for nextEventMatchingMask:untilDate:inMode:dequeue:
states "events that do not match one of the specified event types are
left in the queue.". That seems a little odd. Does this mean that if
an event loop only asks for mouse events then any pressed keys will be
processed once the loop finishes? That'd be weird.
Yes, that's what it means. It's up to you to prevent that weird outcome. If you were to read a version of the Cocoa Event Handling Guide from this decade, you'd find there's a section on how to deal with this. ;-P
Is it possible to peek at a message in the event queue without removing it. eg: the Windows version of my library uses this to close
the popup when it's clicked outside, but leaves the click event in the
queue so that clicking outside the popup on a another button doesn't
require a second click.
Yes. Did you notice the "dequeue:" parameter of nextEventMatchingMask:untilDate:inMode:dequeue:? If you pass NO for that, then the event is left in the queue.
I've read and re-read about run loop modes but still don't really get it. A good explanation of what these are for would be great.
It's hard to know what to tell you without knowing what you're confused about and how the Apple guide failed you.
Are you familiar with handling multiple asynchronous communication channels using a loop around select(), poll(), epoll(), or kevent()? It's kind of like that, but a bit more automated. Not only do you build a data structure which lists the input sources you want to monitor and what specific events on those input sources you're interested in, but each input source also has a callback associated with it. Running the run loop is like calling one of the above functions to wait for input but also, when input arrives, calling the callback associated with the source to handle that input. You can run a single turn of that loop, run it until a specific time, or even run it indefinitely.
With run loops, the input sources can be organized into sets. The sets are called "modes" and identified by name (i.e. a string). When you run a run loop, you specify which set of input sources it should monitor by specifying which mode it should run in. The other input sources are still known to the run loop, but just ignored temporarily.
The -nextEventMatchingMask:untilDate:inMode:dequeue: method is, more or less, running the thread's run loop internally. In addition to whatever input sources were already present in the run loop, it temporarily adds an input source to monitor events from the windowing system, including mouse and key events.
Are there any other good examples of implementing an event loop for a popup. Even better would be pseudo-code for what the built in
NSApplication run loop does.
There's old Apple sample code, which is actually their implementation of GLUT. It provides a subclass of NSApplication and overrides the -run method. When you strip away some stuff that's only relevant for application start-up or GLUT, it's pretty simple. It's just a loop around -nextEventMatchingMask:... and -sendEvent:.

Create a program that alters the execution of a windows application

I have a windows application which has several sub-forms. i have to navigate through 5 or 6 forms to reach the form i need. this is time consuming since i have to open it several times through the day and i do it daily.
my need: i dont have the source project for this application, i got it as an executable program, but i need to create some application that does these steps for me automatically. In other words i need to find a way to automatically click the buttons that navigate through the forms and opens the form i need from step one.
is there any way i can do this ?
There is indeed, though generic solutions already exist to perform just this kind of function to arbitrary programs.
You can use Spy++ or a resource-editor, like ResHack or ResEdit to look at the program and get the control ids of the navigation buttons.
Once done, you can get a handle to the program itself and then send messages to it's WindowProcedure that would be generated if the user clicked the controls with a mouse,
Another alternative, is to get the position of the running target application, after you've got it's HWND, by using the GetWindowRect function. You could then use this position along with vert/horiz distances to generate mouse events.
The two have more-or-less the same result, though some applications won't work with approach #1.
In one instance, you need to use Spy++ to get the control IDs.
In the other instance, you need to use an image editor to get the pixel offsets of the controls.
In both instances, you'll need to use FindWindow, along with the window's title-text in order to get a HWND handle.
You could use a combination of the two - asking the program itself with GetDlgItem for the handle of the controls you need to click. You could then query the control for its position, before using mouse_event to position the mouse above it and again to click it.
Quite a few ways to skin this cat, actually.
Pre-existing solutions like AutoIt are said to be very easy to use and will be much easier than coding a new program for each target.

Using GUI causes "Sleep?" making Audio stutter/stop

Okay, as Title says.
For example, i use NAudio to playback what i record (loopback if you want).
And if i click on the GUI (the top part, so i can move the window).
It will cause a "sleep", and when that happens the current activity (Audio playback) stops.
And then it continues afterwards.
But i want to remove that, as i don´t know any other application that has it, so it´s probably something to do with how i am programming.
Please keep it simple, i am extremely new to c#.
I am guessing on Bakckgroundworker or something, but i couldn´t get it to work.
So hopping for a more concrete answer.
This was just me not understanding that using the Main Thread in a window form will cause anything on the GUI to be run on it.
Meaning, if i move the GUI, that movement will be Priority over the rest of the code, so everything else will get paused if run on that thread.
Perhaps it differ from object to object, but in this scenario it was the case, so i just moved it to a separate thread and it´s solved.

Debugging: step into DispatchMessage()

I am trying to debug a very old C program in visual studio. I was stepping through some code line by line and came to a line DispatchMessage(&msg); I wanted to see where the code went next, so I clicked the "Step into" button, but I was not taken to any new code that processed the message, instead the little yellow arrow just stepped along to the next line down the same page...
Is this expected behaviour? How can I see what DispatchMessage actually did?
Could this be an indication that the window handler is not set up correctly?
extra info: The task I was tring to debug was the processing of a mouse click on a particular window. I had displayed the msg structure, and msg.hwnd was the window I had clicked on (I used Winspector to confirm). The msg.message was 513 (=WM_LBUTTONDOWN).
This is completely expected behaviour...
DispatchMessage() is implemented in User32.dll and as such, the source code is not available. For the most part, you have to treat Win32 API calls as blackboxes. At times, this can really make debugging Win32 code a challenge.
Remember, there are some tricks in your arsenal for debugging this kind of thing:
Go on treating DispatchMessage() as a black box. Place a breakpoint on the WndProc you expect to receive the WM_LBUTTONDOWN and continue debugging there.
Have Winspector log the messages coming into all of the windows involved. This can help make sure the message is received and in the order you are expecting.
If worst comes to worst, you may have to step into DispatchMessage() or some other API call, looking at its disassembly. Most of the time, nothing good comes from that (but I always learn something when I do).
Chances are that option #3 won't be necessary and your time would be better spent debugging around DispatchMessage() rather than within it.

How Imitate a [Ctrl+Left mouse click] on the center of the form or open another program and type in a word?

Babylon dictionary and a couple of other dictionaries allow to click on any word in any windows program
and automatically recognize the word under the cursor, and at once open the dictionary window while searching for that word in installed dictionaries.
You can on the other hand open your dictionary, type in your word and press Enter, the result will be the same.
There's a Delphi form, containing a text label, for example with the word "Automaton".
My question is:
How to send a word from my Delphi application right into the dictionary window, as if you typed it manually and pressed Enter?
The best solution is to send some message through the Windows mechanism, but if it is too complicated, there's another solution, and so the second answer: as I described, we need to model a [Ctrl+left mouse] click on a form where this word is displayed on a form [ a visual label on the screen of my Delphi application], to be exact, on some central pixel of this label.
Could you kindly give an advice how to do one thing or another in Delphi ?
** edit:
The problem with AppActivate is this: Babylon dict has a daemon part that seats in the tray.
In the task manager a real window where the text should be input also is named 'Babylon'.
So AppActivate('Babylon') tries to bring to front the non-visual part of the application.
Do you have any suggestion how to determine the windows handle or something of a real visual part of the application? In the task manager, I repeat both visual and non-visual parts are named 'Babylon'.
I cannot offer an answer so much as some insight and advice...
There are certain applications which "intercept" keyboard and mouse instructions, and essentially "nullify" them if they are being immitated by software. Generally-speaking, you'd only see this in proper AntiVirus software such as Kaspersky by design... however:
The way some (not many, but some) programs hook keyboard and mouse inputs, as a side-effect, behave the same way. If you have attempted all of the advice given as comments above, and cannot get Babylon to trigger an action as a result, it is likely Babylon behaves as I have described.
If what I suspect is true, then the method you are attempting is simply not possible (at least, not using any simple Pascal code on its own... ASM might be able to do it but that's beyond my knowledge).
A better solution may be to do a little research to see if any of the following options are available to you:
1) Does Babylon have a Pipeline or API you can use to interface your application(s) with it?
2) Is the particular functionality you require of Babylon accessible through one (or more) DLL files distributed as part of Babylon?
3) Is there an alternative to using Babylon for your needs?
I know it's not an answer as such (certainly not one you'd want to hear), but it may point you in a better direction.

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