static DWORD
TransmitFileMap (SOCKET sd, HANDLE fd, DWORD n)
{
HANDLE hmap = CreateFileMapping(fd, NULL, PAGE_READONLY, 0, 0, NULL);
DWORD res = 0;
if (hmap) {
DWORD size_hi, size_lo;
char *base = NULL;
size_lo = GetFileSize(fd, &size_hi);
if (size_lo != -1L || SYS_ERRNO == NO_ERROR) {
LONG off_hi = 0L, off_lo;
int64_t size;
DWORD len;
off_lo = SetFilePointer(fd, 0, &off_hi, SEEK_CUR);
size = INT64_MAKE(size_lo, size_hi) - INT64_MAKE(off_lo, off_hi);
len = (size < (int64_t) ~((DWORD) 0))
? (DWORD) size : ~((DWORD) 0);
if (n <= 0 || n > len) n = len;
size_lo = (off_lo & SYS_GRAN_MASK);
base = MapViewOfFile(hmap, FILE_MAP_READ,
off_hi, (off_lo & ~SYS_GRAN_MASK), 0);
}
CloseHandle(hmap);
if (base) {
WSABUF buf = {n, base + size_lo};
if (!WSASend(sd, &buf, 1, &res, 0, NULL, NULL)) {
LONG off_hi = 0L;
SetFilePointer(fd, res, &off_hi, SEEK_CUR);
}
UnmapViewOfFile(base);
}
}
return res;
}
/*
* Arguments: membuf_udata, fd_udata, [protection (string: "rw"),
* offset (number), num_bytes (number), private/shared (boolean)]
* Returns: [membuf_udata]
*/
static int
mem_map (lua_State *L)
{
struct membuf *mb = checkudata(L, 1, MEM_TYPENAME);
const fd_t *fdp = checkudata(L, 2, FD_TYPENAME);
fd_t fd = fdp ? (fd_t) *fdp : (fd_t) -1; /* named or anonymous mapping */
const char *protstr = lua_tostring(L, 3);
const lua_Number offset = lua_tonumber(L, 4);
const int64_t off = (int64_t) offset; /* to avoid warning */
size_t len = (size_t) lua_tointeger(L, 5);
const int is_private = lua_isboolean(L, -1) && lua_toboolean(L, -1);
int prot = 0, flags;
void *ptr;
#ifndef _WIN32
#ifndef MAP_ANON
int is_anon = 0;
#endif
sys_vm_leave();
/* length */
if (!len) {
struct stat sb;
if (fd == -1 || fstat(fd, &sb) == -1)
goto err;
sb.st_size -= off;
len = ((uint64_t) sb.st_size < (uint64_t) ~((size_t) 0))
? (size_t) sb.st_size : ~((size_t) 0);
}
/* protection and flags */
prot = PROT_READ;
if (protstr) {
if (protstr[0] == 'w')
prot = PROT_WRITE;
else if (protstr[1] == 'w')
prot |= PROT_WRITE;
}
flags = is_private ? MAP_PRIVATE : MAP_SHARED;
/* anonymous shared memory? */
if (fd == -1) {
#ifdef MAP_ANON
flags |= MAP_ANON;
#else
if ((fd = open("/dev/zero", O_RDWR)) == -1)
goto err;
is_anon = 1;
#endif
}
/* map file to memory */
ptr = mmap(0, len, prot, flags, (int) fd, off);
#ifndef MAP_ANON
if (is_anon) close(fd);
#endif
if (ptr == MAP_FAILED) goto err;
#else
sys_vm_leave();
/* length */
if (!len) {
DWORD size_hi, size_lo;
int64_t size;
if (fd == (fd_t) -1) goto err;
size_lo = GetFileSize(fd, &size_hi);
if (size_lo == (DWORD) -1L && SYS_ERRNO != NO_ERROR)
goto err;
size = INT64_MAKE(size_lo, size_hi) - off;
len = ((uint64_t) size < (uint64_t) ~((DWORD) 0))
? (DWORD) size : ~((DWORD) 0);
}
/* protection and flags */
if (protstr && (protstr[0] == 'w' || protstr[1] == 'w')) {
prot = PAGE_READWRITE;
flags = FILE_MAP_WRITE;
} else {
prot = PAGE_READONLY;
flags = FILE_MAP_READ;
}
if (is_private) {
prot = PAGE_WRITECOPY;
flags = FILE_MAP_COPY;
}
/* map file to memory */
{
const DWORD off_hi = INT64_HIGH(off);
const DWORD off_lo = INT64_LOW(off);
HANDLE hmap = CreateFileMapping(fd, NULL, prot, 0, len, NULL);
if (!hmap) goto err;
ptr = MapViewOfFile(hmap, flags, off_hi, off_lo, len);
CloseHandle(hmap);
if (!ptr) goto err;
}
#endif /* !Win32 */
sys_vm_enter();
mb->flags |= MEM_MAP;
mb->len = len;
mb->data = ptr;
lua_settop(L, 1);
return 1;
err:
sys_vm_enter();
return sys_seterror(L, 0);
}
