/***

    mockcpp is a generic C/C++ mock framework.

    Copyright (C) <2010>  <Darwin Yuan: darwin.yuan@gmail.com>

	                      <Chen Guodong: sinojelly@gmail.com>



    This program is free software: you can redistribute it and/or modify

    it under the terms of the GNU General Public License as published by

    the Free Software Foundation, either version 3 of the License, or

    (at your option) any later version.



    This program is distributed in the hope that it will be useful,

    but WITHOUT ANY WARRANTY; without even the implied warranty of

    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

    GNU General Public License for more details.



    You should have received a copy of the GNU General Public License

    along with this program.  If not, see <http://www.gnu.org/licenses/>.

***/



#include <string.h>

#include <inttypes.h>

#include <sys/mman.h>



#include <mockcpp/CodeModifier.h>



#define PAGE_ALIGN_BITS  12



//////////////////////////////////////////////////////////////////

#define PAGE_SIZE   (1 << PAGE_ALIGN_BITS)

#define ALIGN_TO_PAGE_BOUNDARY(addr) (void*) (((uintptr_t)addr) & (~((1<<(PAGE_ALIGN_BITS))-1)))

//////////////////////////////////////////////////////////////////



MOCKCPP_NS_START



bool CodeModifier::modify(void *dest, const void *src, size_t size)

{

    if(::mprotect(ALIGN_TO_PAGE_BOUNDARY(dest), PAGE_SIZE * 2, PROT_EXEC | PROT_WRITE | PROT_READ ) != 0)

    {  

       return false; 

    }



    ::memcpy(dest, src, size);

    ::msync(dest, size, MS_SYNC);





#if 0

	#if BUILD_FOR_X86

	//(void)memcpy(dest, src, size); // something wrong on linux: after memcpy(or 5 single byte copy),  the 4 bytes following jmp, src is 0x07c951b0, but dest is 0x07b851b0. so use unsigned int *, it works ok.

	*((unsigned char *)dest) = *((unsigned char *)src);

	*((unsigned long *)((unsigned long)dest + 1)) = *((unsigned long *)((unsigned long)src + 1));

	#else

	*((unsigned char *)dest) = *((unsigned char *)src);

	*((unsigned char *)((unsigned long)dest + 1)) = *((unsigned char *)((unsigned long)src + 1));

    // after this line, dest+2 is 0x00c90000, not 0, so change it.

	*((unsigned char *)((unsigned long)dest + 2)) = *((unsigned char *)((unsigned long)src + 2));

	*((unsigned char *)((unsigned long)dest + 3)) = *((unsigned char *)((unsigned long)src + 3));

	*((unsigned char *)((unsigned long)dest + 4)) = *((unsigned char *)((unsigned long)src + 4));

	*((unsigned char *)((unsigned long)dest + 5)) = *((unsigned char *)((unsigned long)src + 5));

	*((unsigned long *)((unsigned long)dest + 6)) = *((unsigned long *)((unsigned long)src + 6));

	#endif

#endif



	return true;

}





MOCKCPP_NS_END