ALTER TABLE - C / C++ / MFC Discussion Boards

Re: method of hook dll

Anton Mikhalyov11-Mar-06 18:17

Anton Mikhalyov

11-Mar-06 18:17

HOW WHAT wrote:
have other method of hook dll and not need modification the Import Table and Export Table.

you can change first bytes of function to far jmp that points on your code.

Re: method of hook dll

HOW WHAT11-Mar-06 18:41

HOW WHAT

11-Mar-06 18:41

how to ? ex.?

Re: method of hook dll

Anton Mikhalyov11-Mar-06 20:52

Anton Mikhalyov

11-Mar-06 20:52

This example shows the hook of GetModuleHandleW in target process(process where you injected your dll). It works only in 32-bit windows.
If you injected your dll into multithreaded process you must synchronize execution of this code with other threads or program sometimes may crash.

<br />
#define BYTES_COUNT 0x05<br />
<br />
BYTE firstBytes[BYTES_COUNT];<br />
void *pfnGetModuleHandle;<br />
HANDLE __stdcall Handler(HANDLE hModule);<br />
<br />
// Only running process hook<br />
BOOL HookGetModuleHandle()<br />
{<br />
	HANDLE hKernel32;<br />
	DWORD dwOldProtect;<br />
<br />
	hKernel32 = LoadLibrary(_T("kernel32.dll"));<br />
	pfnGetModuleHandle = GetProcAddress((HMODULE)hKernel32, "GetModuleHandleW");<br />
<br />
	if (hKernel32 == NULL || pfnGetModuleHandle == NULL)<br />
	{<br />
		return FALSE;<br />
	}<br />
<br />
	memcpy(&firstBytes, pfnGetModuleHandle, BYTES_COUNT);<br />
<br />
	if (!VirtualProtect(pfnGetModuleHandle, BYTES_COUNT, PAGE_READWRITE, &dwOldProtect))<br />
	{<br />
		return FALSE;<br />
	}<br />
<br />
	*((BYTE*)pfnGetModuleHandle) = 0xE9;<br />
	*((DWORD*)(((BYTE*)pfnGetModuleHandle)+1)) = (DWORD)Handler - (DWORD)pfnGetModuleHandle - BYTES_COUNT;<br />
<br />
	if (!VirtualProtect(pfnGetModuleHandle, BYTES_COUNT, dwOldProtect, NULL))<br />
	{<br />
		return FALSE;<br />
	}<br />
<br />
	return TRUE;<br />
}<br />
<br />
BOOL UnhookGetModuleHandle()<br />
{<br />
	DWORD dwOldProtect;<br />
<br />
	if (!VirtualProtect(pfnGetModuleHandle, BYTES_COUNT, PAGE_READWRITE, &dwOldProtect))<br />
	{<br />
		return FALSE;<br />
	}<br />
<br />
	memcpy(pfnGetModuleHandle, &firstBytes, BYTES_COUNT);<br />
<br />
	if (!VirtualProtect(pfnGetModuleHandle, BYTES_COUNT, dwOldProtect, NULL))<br />
	{<br />
		return FALSE;<br />
	}<br />
<br />
	return TRUE;<br />
}<br />
<br />
HANDLE __stdcall Handler(HANDLE hModule)<br />
{<br />
	HANDLE returned;<br />
	printf("GetModuleHandleW call detected\n");<br />
	UnhookGetModuleHandle();<br />
	__asm {<br />
		push hModule<br />
		call pfnGetModuleHandle<br />
		mov returned, eax<br />
	}<br />
	HookGetModuleHandle();<br />
}<br />

Re: method of hook dll

HOW WHAT12-Mar-06 1:24

HOW WHAT

12-Mar-06 1:24

your method and modification the Import Table, which will be highness and safe?

Re: method of hook dll

Anton Mikhalyov12-Mar-06 3:55

Anton Mikhalyov

12-Mar-06 3:55

My method is better to use, because it never fail, except when application detected and removed hook(very very rarely), but it creates additional problems with synchronization in mt applications and it doesn't work on windows other than 32 bit(without modification).
IAT modification is also good method, but this hook wouldn't work if application directly calls functions(call GetProcAddress to retrieve address of function...). Second method fails more offen than first.
Also you can create a dll that debugs process in which it injected by inserting int3 instructions into functions you want to hook. If number of functions to hook =< 4 you can use hardware breakpoints, setting hardware breakpoints do not require any code modifications.

Re: method of hook dll

HOW WHAT12-Mar-06 4:52

HOW WHAT

12-Mar-06 4:52

1.Your method if had some call hooked function may be happen some exception, right?

2.How to do like you say
"Also you can create a dll that debugs process in which it injected by inserting int3 instructions into functions you want to hook. If number of functions to hook =< 4 you can use hardware breakpoints, setting hardware breakpoints do not require any code modifications. "

Some time ago, I download codeproject about use debug process to inject dll, but in win98 all application will happen crash.

Re: method of hook dll

Anton Mikhalyov13-Mar-06 1:17

Anton Mikhalyov

13-Mar-06 1:17

HOW WHAT wrote:
1.Your method if had some call hooked function may be happen some exception, right?

Only when application threads are not synchronized and context of current thread(that now hooking function) is switched to other that calls hooked function.

HOW WHAT wrote:
2. How to do like you say

There is an error in code you just downloaded.
Armadillo protector uses the same technique and it works best on Windows 9x\Me
Give me the URL of this example or send it to my mail - sharebyte gmail com

ALTER TABLE

The Little Lloyd11-Mar-06 11:11

The Little Lloyd

11-Mar-06 11:11

Hello all!
Problem: I am using SQL frm within my C++ code.
Can anyone tell me HOW to change a name of a column of a table (for a MS Access 2000 database)?

Using "ALTER TABLE table_name RENAME COLUMN old_name TO new_name" seems not to work because of syntax failure !

Thanks

Re: ALTER TABLE

Jeremy Falcon11-Mar-06 15:12

Jeremy Falcon

11-Mar-06 15:12

What's the exact query you're using?

Jeremy Falcon

Re: ALTER TABLE

The Little Lloyd11-Mar-06 19:43

The Little Lloyd

11-Mar-06 19:43

The table is: Cars
The column I want to rename: Colour (of type CHARACTER VARYING(255))

ALTER TABLE Cars RENAME COLUMN Colour TO FormerColour CHARACTER VARYING(255)

Thanks

-- modified at 1:44 Sunday 12th March, 2006

Re: ALTER TABLE

Jeremy Falcon11-Mar-06 20:07

Jeremy Falcon

11-Mar-06 20:07

You don't need the the type of the column to rename it. This should do the job...

ALTER TABLE Cars RENAME COLUMN Colour TO FormerColour;

Also, CHARACTER VARYING is just a synonym for TEXT if you'd rather use that to keep your queries smaller.

Jeremy Falcon

Re: ALTER TABLE

The Little Lloyd11-Mar-06 20:52

The Little Lloyd

11-Mar-06 20:52

I've already done that. I still get an sql syntax error. It simply does not work Frown | :-(

with (my) access 2000. Other idea?

Re: ALTER TABLE

Jeremy Falcon12-Mar-06 11:19

Jeremy Falcon

12-Mar-06 11:19

Did you try running it specifically as a DDL query (under the Query/SQL Specific menu)?

If that still doesn't work, then I'm so glad I don't have to use Access anymore. Smile | :)

However, if you must use Access then you could always rename the column using ADOX rather than a SQL statement. Or if all else fails, you could still pull off the same thing by using separate queries like this...

ALTER TABLE Table1 ADD COLUMN New_Col TEXT(255);
UPDATE Table1 SET New_Col = Old_Col;
ALTER TABLE Table1 DROP COLUMN Old_Col;

Jeremy Falcon

Bold text

yaaqub11-Mar-06 10:22

yaaqub

11-Mar-06 10:22

HI,
I want my inputs to be BOLD TEXT.

JOHN,K

Re: Bold text

C^hris L^osinger11-Mar-06 10:37

C^hris L^osinger

11-Mar-06 10:37

ok

Cleek | Image Toolkits | Thumbnail maker

Re: Bold text

John R. Shaw11-Mar-06 22:55

John R. Shaw

11-Mar-06 22:55

I am still laughing, at least I told him not to post that again.

INTP
Every thing is relative...

Re: Bold text

Jörgen Sigvardsson11-Mar-06 11:02

Jörgen Sigvardsson

11-Mar-06 11:02

Create a bold font, and pass it to edit box's SetFont() method...

Re: Bold text

Hamid_RT11-Mar-06 17:17

Hamid_RT

11-Mar-06 17:17

use Createfont
http://msdn2.microsoft.com/en-us/library/2ek64h34.aspx[^]

Re: Bold text

Jörgen Sigvardsson11-Mar-06 22:18

Jörgen Sigvardsson

11-Mar-06 22:18

Why are you telling me this?

Re: Bold text

John R. Shaw11-Mar-06 22:48

John R. Shaw

11-Mar-06 22:48

I whish you where kidding, do not asks questions like this agian.

INTP
Every thing is relative...

path class

xyhan11-Mar-06 8:52

xyhan

11-Mar-06 8:52

Is there any MFC class for path operation? for example, to replace the API
GetCurrentPath,FindFirstFile functions?

Thanks

Re: path class

C^hris L^osinger11-Mar-06 10:38

C^hris L^osinger

11-Mar-06 10:38

CFileFind

Cleek | Image Toolkits | Thumbnail maker

Re: path class

Hamid_RT11-Mar-06 17:20

Hamid_RT

11-Mar-06 17:20

Hi,
GetCurrentDirectory

Network Address translation

mahesh_patil16611-Mar-06 8:50

mahesh_patil166

11-Mar-06 8:50

Hi all,
I want to find out how to achive network address translation in visual C++;

Re: Network Address translation

J512198212-Mar-06 17:27

J5121982

12-Mar-06 17:27

for the below reasons u need to go for NAT?

Why NAT?

• With the explosion of the Internet and the increase in home networks and business networks, the number of available IP addresses is simply not enough. The obvious solution is to redesign the address format to allow for more possible addresses. This is being developed (called IPv6), but will take several years to implement because it requires modification of the entire infrastructure of the Internet.
• Shortage of IP addresses is only one reason to use NAT
• For Security and Administration
• This is where NAT comes to the rescue.

How NAT works?

Network Address Translation allows a single device, such as a router to act as an agent between the Internet (or "public network") and a local (or "private") network. This means that only a single, unique IP address is required to represent an entire group of computers.

JAYARAJ

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