int vm_release(void * addr, size_t size)
{
// Safety check: don't try to release memory that was not allocated
if (addr == VM_MAP_FAILED)
return 0;
#ifdef HAVE_MACH_VM
if (vm_deallocate(mach_task_self(), (vm_address_t)addr, size) != KERN_SUCCESS)
return -1;
#else
#ifdef HAVE_MMAP_VM
if (munmap((caddr_t)addr, size) != 0)
return -1;
#else
#ifdef HAVE_WIN32_VM
if (VirtualFree(align_addr_segment(addr), 0, MEM_RELEASE) == 0)
return -1;
#else
free(addr);
#endif
#endif
#endif
return 0;
}
int vm_acquire_fixed(void * addr, size_t size, int options)
{
errno = 0;
// Fixed mappings are required to be private
if (options & VM_MAP_SHARED)
return -1;
#ifndef HAVE_VM_WRITE_WATCH
if (options & VM_MAP_WRITE_WATCH)
return -1;
#endif
#if defined(HAVE_MACH_VM)
// vm_allocate() returns a zero-filled memory region
kern_return_t ret_code = vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, 0);
if (ret_code != KERN_SUCCESS) {
errno = vm_error(ret_code);
return -1;
}
#elif defined(HAVE_MMAP_VM)
int fd = zero_fd;
int the_map_flags = translate_map_flags(options) | map_flags | MAP_FIXED;
if (mmap((caddr_t)addr, size, VM_PAGE_DEFAULT, the_map_flags, fd, 0) == (void *)MAP_FAILED)
return -1;
#elif defined(HAVE_WIN32_VM)
// Windows cannot allocate Low Memory
if (addr == NULL)
return -1;
int alloc_type = MEM_RESERVE | MEM_COMMIT;
if (options & VM_MAP_WRITE_WATCH)
alloc_type |= MEM_WRITE_WATCH;
// Allocate a possibly offset region to align on 64K boundaries
LPVOID req_addr = align_addr_segment(addr);
DWORD req_size = align_size_segment(addr, size);
LPVOID ret_addr = VirtualAlloc(req_addr, req_size, alloc_type, PAGE_EXECUTE_READWRITE);
if (ret_addr != req_addr)
return -1;
#else
// Unsupported
return -1;
#endif
// Explicitely protect the newly mapped region here because on some systems,
// say MacOS X, mmap() doesn't honour the requested protection flags.
if (vm_protect(addr, size, VM_PAGE_DEFAULT) != 0)
return -1;
return 0;
}
static inline DWORD align_size_segment(LPVOID addr, DWORD size)
{
return size + ((vm_uintptr_t)addr - (vm_uintptr_t)align_addr_segment(addr));
}
static inline DWORD align_size_segment(LPVOID addr, DWORD size)
{
D(bug("%s\n", __func__));
return size + ((vm_uintptr_t)addr - (vm_uintptr_t)align_addr_segment(addr));
}
