myvtm/spbase/sp_shm.c

#include "precompile.h"
#include "sp_shm.h"
#include "sp_def.h"

#include "shm_mem.h"
#include <winpr/file.h>

#define MEM_KEY		95555
#define MEM_SIZE	(SHM_MEM_SIZE * 1024 * 1024)

#define GET_ADDRESS(x) ((void*)((1+(x)) << 28))

static int g_newcreator = -1;

int sp_shm_get_range(int mask)
{
	int i;
	int range = 0;
	/*if start to refactor, you can think about :
	 * https://forums.pcsx2.net/Thread-blog-VirtualAlloc-on-Linux
	 * VirtualAlloc has been implement at WinPR
	 */
	for (i = 0; i < 7; ++i) {
		void *address = GET_ADDRESS(i);//0x10000000, 0x20000000, ..., 0x80000000
		void *ret_address = VirtualAlloc(address, MEM_SIZE, MEM_RESERVE, PAGE_NOACCESS);
		if (address == ret_address) {
			range |= 1 << (i + 1);
		}
		if (ret_address)
#if _WIN32
			VirtualFree(ret_address, 0, MEM_RELEASE);
#else
			VirtualFree(ret_address, MEM_SIZE, MEM_RELEASE);
#endif
	}

	return range & mask;
}

void *sp_shm_init(int range, int newcreator)
{
	int i;
	void *address;

	for (i = 0; i < 7; ++i) {
		if (range & (1 << (i+1))) {
			address = GET_ADDRESS(i);
			if (shm_mem_init2(MEM_KEY, address, newcreator) == 0) {
				if (address != NULL)
					g_newcreator = newcreator;
				return address;
			}
		}
	}
	return NULL;
}

void sp_shm_term()
{
	/*we don't know why, this has been annotated at windows platform*/
	if(sp_shm_is_newalloc())
		shm_mem_destroy();
}

int sp_shm_is_newalloc()
{
	if (g_newcreator == -1)
		return 0;
	return g_newcreator;
}