Re: Write a function to cause a thread to wait - C / C++ / MFC Discussion Boards

Garth J Lancaster28-May-10 15:07

28-May-10 15:07

well, your formatting sucks for a start .. I cant quite put my finger on whats wrong .. looking at examples, I cant help feel that this (your code),

BOOL WINAPI MyWriteProcessMemory(
HANDLE hProcess, // handle to process
LPVOID lpBaseAddress, // base of memory area
LPVOID lpBuffer, // data buffer
DWORD nSize, // number of bytes to write
LPDWORD lpNumberOfBytesWritten) // number of bytes written
{
BOOL nResult=WriteProcessMemory(hProcess,lpBaseAddress,lpBaseAddress,nSize,lpNumberOfBytesWritten); //call origin function
MessageBoxA(NULL,(LPCTSTR)lpBaseAddress,"Hook!",MB_OK); 
return nResult;
}

should be this :-

BOOL WINAPI MyWriteProcessMemory(
HANDLE hProcess, // handle to process
LPVOID lpBaseAddress, // base of memory area
LPVOID lpBuffer, // data buffer
DWORD nSize, // number of bytes to write
LPDWORD lpNumberOfBytesWritten) // number of bytes written
{
BOOL nResult=CopyWriteProcessMemory(hProcess,lpBaseAddress,lpBaseAddress,nSize,lpNumberOfBytesWritten); //call origin function
MessageBoxA(NULL,(LPCTSTR)lpBaseAddress,"Hook!",MB_OK); 
return nResult;
}

CopyWriteProcessMemory has replaced WriteProcessMemory so calling WriteProcessMemory I dont think will work. Ive seen 'Real_' used instead of 'Copy', to make it a bit more obvious .. ie instead of

CopyWriteProcessMemory you would have Real_WriteProcessMemory

Obviously that means you start with

DETOUR_TRAMPOLINE(BOOL WINAPI Real_WriteProcessMemory(HANDLE, LPVOID, LPVOID, DWORD, LPDWORD), WriteProcessMemory);

Other than that I cant spot anything dramatically wrong ..

You might want to compare your code with this http://code.google.com/p/dxhook/source/browse/trunk/dxhook.cpp?r=4[^] to see if it helps

'g'

Re: about Hook WriteProcessMemory

rockago28-May-10 21:48

rockago

28-May-10 21:48

thx.
But when I taked "WriteProcessMemory "to" Real_WriteProcessMemory", After injection into or unable to carry out "MessageBoxA." Frown | :(

Re: about Hook WriteProcessMemory

Garth J Lancaster28-May-10 22:27

Garth J Lancaster

28-May-10 22:27

so what does your code look like now ?

also, you should be aware of (from http://msdn.microsoft.com/en-us/library/ms681674(VS.85).aspx[^] )

"hProcess [in]
A handle to the process memory to be modified. The handle must have PROCESS_VM_WRITE and PROCESS_VM_OPERATION access to the process."

so you may not have some permissions to write to that memory -
as that page also says, you can do a call to GetLastError - these 2 pages may help

http://msdn.microsoft.com/en-us/library/ms679360(v=VS.85).aspx[^]

http://msdn.microsoft.com/en-us/library/ms680582(v=VS.85).aspx[^]

so see what the error code is.

Finally, have you checked that your process handle of the process you are trying to write to is valid ? (Im presuming somewhere else in your code you are doing an OpenProcess on the Process ID you are trying to write to)

'g'

Re: about Hook WriteProcessMemory

Richard MacCutchan28-May-10 22:22

Richard MacCutchan

28-May-10 22:22

rockago wrote:
MessageBoxA(NULL,(LPCTSTR)lpBaseAddress,"Hook!",MB_OK);

lpBaseAddress is a pointer to void, I have no idea what it is pointing to but unless it's a string of ASCII characters you cannot cast it to LPCTSTR and expect MessageBoxA() to work.

It's time for a new signature.

Re: about Hook WriteProcessMemory

Garth J Lancaster28-May-10 22:33

Garth J Lancaster

28-May-10 22:33

if thats what his issue is Ive been wasting my breath !!! oh well ..

Re: about Hook WriteProcessMemory

Richard MacCutchan28-May-10 23:09

Richard MacCutchan

28-May-10 23:09

I think a bit of lateral thinking and lots of guesswork is needed here. I only noticed that because he mentioned the MessageBox call in two posts. I've no idea what the rest of it is, or is supposed to be, doing.

It's time for a new signature.

Write a function to cause a thread to wait

Danzy8328-May-10 9:08

Danzy83

28-May-10 9:08

Hi, I have written a function to cause a thread to wait for a given time. But the problem is that If this function is called, I notice from task manager (in Windows) that the CPU Usage shoots up to 100 percent. But if I rather use the Windows function Sleep(), the CPU Usage falls back to around 2%, 3%, and 4%. The following is how I wrote the function, with the header file <time.h> included.

void Wait(clock_t milliseconds)
{
clock_t delay_time = milliseconds + clock();

while (delay_time > clock())
;

return;
}

I don't know why my CPU usage shoots up to 100% when I use this function rather than Windows Sleep() function. I don't want my application to assume the use of Windows. Please help.

Re: Write a function to cause a thread to wait

CPallini28-May-10 9:19

CPallini

28-May-10 9:19

Dan_K wrote:
that the CPU Usage shoots up to 100 percent

No wonder: you're using the CPU, aren't you?
That's not the best way to pause an application on a multitasking system.
Smile | :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke

[My articles]

Re: Write a function to cause a thread to wait

Luc Pattyn28-May-10 9:33

Luc Pattyn

28-May-10 9:33

You should upgrade your hardware. If you buy a dual-core system, it will become twice as efficient: the CPU load will be around 50%. Or go for a quad-core and see it sitting idle with a load of a mere 25%.

If you don't like that idea, you should either use a sleep function or a timer.

FWIW: you could do both to make absolutely sure.

Laugh | :laugh:

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]

I only read formatted code with indentation, so please use PRE tags for code snippets.

I'm not participating in frackin' Q&A, so if you want my opinion, ask away in a real forum (or on my profile page).

Re: Write a function to cause a thread to wait

Cedric Moonen28-May-10 10:02

Cedric Moonen

28-May-10 10:02

Your CPU usage goes to 100% simply because you are actually doing something: the while loop and the checks are operations done by the CPU, and in your case without interruption, so the CPU is always busy.

Cédric Moonen
Software developer

Charting control [v3.0]
OpenGL game tutorial in C++

Re: Write a function to cause a thread to wait

CPallini28-May-10 11:08

CPallini

28-May-10 11:08

Cedric Moonen wrote:
so the CPU is always busy

It's the ancient wise's rule: "keep the CPU busy and the brain sleeping..." Big Grin | :-D

Re: Write a function to cause a thread to wait

malaugh28-May-10 11:18

malaugh

28-May-10 11:18

All the CPU cycles are going to reaing the clock over and over. If you want to be independant of windows, the function uSleep is Unix the equivelent of Sleep, just add

<br />
#ifndef WIN32<br />
#define Sleep(x) uSleep(x * 1000)<br />
#endif<br />
<br />

To the top of your code

Re: Write a function to cause a thread to wait

Richard MacCutchan28-May-10 22:17

Richard MacCutchan

28-May-10 22:17

Dan_K wrote:
I don't know why my CPU usage shoots up to 100%

Time to start learning how computers work. Wink | ;)

It's time for a new signature.

OnPrint from IE

mesajflaviu28-May-10 4:34

mesajflaviu

28-May-10 4:34

I have a strange problem : an .pdf file load in IE is not printed !
I made an MDI project , with CView based on CHtmlView , where I load an .pdf file. The problem is that Print , from File menu not working !!! If I load an any other kind of file ( .html , etc. ), Print function ... Why ? I work in VC6 , and I have Foxit pdf client ...

Re: OnPrint from IE

mesajflaviu28-May-10 7:43

mesajflaviu

28-May-10 7:43

Ok , I found the problem , it was my pdf client : Foxit Reader .

Allocating memory for function pointers [modified]

SelvaKr28-May-10 4:08

SelvaKr

28-May-10 4:08

Hi,

I am working in a porting project where i have to convert the thread local variables (declared with __declspec(thread)) to TLS allocations (using TLS APIs).
I am able to do it for variables.
How to do it for function pointers? (thread local function pointers)

for example,
I have a thread local function pointer declared as,
__declspec(thread) BOOL (WINAPI *Test)(Short a, _TCHAR b, BOOL c);

Is it possible to convert this by using TLS APIs?

Is it possible to allocate the memory (4 bytes) for pointer "Test"?

Any help is appreciated.

Thanks.

Selva

Re: Allocating memory for function pointers

Aescleal28-May-10 4:16

Aescleal

28-May-10 4:16

Test is just a variable with type:

BOOL (WINAPI *)(Short, _TCHAR, BOOL );

so all you need to do is cast the result of you TLS allocation to that type. If you use a quick typedef it's pretty trivial:

typedef BOOL (WINAPI *test_function_ptr)( Short, _TCHAR, BOOL );

test_function_ptr Test = (test_function_ptr)malloc( sizeof( test_function_ptr ) );

Replace malloc with what ever TLS function you're using and snip, snip, Bob's your Aunty.

Cheers,

Ash

Re: Allocating memory for function pointers

SelvaKr28-May-10 4:41

SelvaKr

28-May-10 4:41

Hi Ash,
Thanks. It works.

Selva

How can draw a Side bar like a CodeProject Left Sidebar?

Le@rner28-May-10 2:53

Le@rner

28-May-10 2:53

Hi all,

i want to use Codeproject Left Sidebar type sidebar in my SDI type Splitter MFC application.

please tell me how can i use it .

if possible please tell me any other styles and designs of side navigation bar.

thanks in advance.

Re: How can draw a Side bar like a CodeProject Left Sidebar?

Richard MacCutchan28-May-10 3:06

Richard MacCutchan

28-May-10 3:06

You would probably need a Tree View[^] control, or CTreeView[^] class.

It's time for a new signature.

Re: How can draw a Side bar like a CodeProject Left Sidebar?

Le@rner28-May-10 18:09

Le@rner

28-May-10 18:09

Can u please show me any example or demo application its really help me.

Re: How can draw a Side bar like a CodeProject Left Sidebar?

Richard MacCutchan28-May-10 22:14

Richard MacCutchan

28-May-10 22:14

You really should learn how to use MSDN/Google/Bing for yourself. Try here[^] for some explanations and samples.

It's time for a new signature.

How do i check whether a window is opened or not Win 32

arun_pk28-May-10 2:21

arun_pk

28-May-10 2:21

how to check the window is opened or not in a win32 application

Re: How do i check whether a window is opened or not Win 32

Aescleal28-May-10 2:30

Aescleal

28-May-10 2:30

FindWindow and FindWindowEx are what you want. You have to know the window class or the title of the window you're digging for but not both.

Cheers,

Ash

Re: How do i check whether a window is opened or not Win 32

Emilio Garavaglia28-May-10 2:50

Emilio Garavaglia

28-May-10 2:50

If "opened" stands for "visible" than IsWindowVisible is the API.
If "opened" means "existent" than IsWindow is the API.

2 bugs found.
> recompile ...
65534 bugs found.
D'Oh! | :doh:

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