Inject sleep() into a function of an external process

I know how to inject a DLL into a running process and also how to utilize functions used internally by the process e.g.

void__stdcall remoteMethod(unsigned short id)
{
typedef void (__stdcall *pFunctionAddress)(unsigned short);
pFunctionAddress pMyFunction = (pFunctionAddress)(0xCAFEBABE);
pMyFunction(id);
}

Now i want to add a sleep() into an existing method in the running process - this is the main loop of the program and doesnt stop for a sec and uses up all processing power.

I know that with frameworks like detours i could make a trampoline function which calls my function and then the original one - however my problem is that the while(1) loop is somewhere within the function of the external process. So i know the offset where the loop starts - and after that i would like to first call sleep() and then continue with the normal route of the loop.

The only alternative i saw so far is binary editing the program but t开发者_Python百科his is not a good solution.

Any suggestion? Thanks

I think you are trying to be too cute here. Just call SuspendThread/ResumeThread alternately on a timer. I know it's ugly, but you aren't going to enter your solution in any beauty pageant I suspect.

1. Post the name of the spin-waiting program.

2. Wait for SO-ers to send hate mail to the developer.

3. Install the update the developer sends you as a bribe to stop the hate mail.

In principle, as long as you've been executed once within the space of the other process, and you know that the loop isn't executing, then you could enabling writing to text pages and patch the actual loop code in situ. You'll need a few redundant bytes to write a call to your function over (extending the function will need a lot of rewriting as all relative offsets will break).

This is not, however, terribly easy nor terribly robust. Consider why you want to to this, and if you can achieve the goal another way.