- w = m->by_fd[fd_index].windows;
- while (w != (unsigned) -1) {
- if (mmap_cache_test_window(m, w, offset, size))
+ woffset = offset & ~((uint64_t) page_size() - 1ULL);
+ wsize = size + (offset - woffset);
+ wsize = PAGE_ALIGN(wsize);
+
+ if (wsize < WINDOW_SIZE) {
+ uint64_t delta;
+
+ delta = PAGE_ALIGN((WINDOW_SIZE - wsize) / 2);
+
+ if (delta > offset)
+ woffset = 0;
+ else
+ woffset -= delta;
+
+ wsize = WINDOW_SIZE;
+ }
+
+ if (st) {
+ /* Memory maps that are larger then the files
+ underneath have undefined behavior. Hence, clamp
+ things to the file size if we know it */
+
+ if (woffset >= (uint64_t) st->st_size)
+ return -EADDRNOTAVAIL;
+
+ if (woffset + wsize > (uint64_t) st->st_size)
+ wsize = PAGE_ALIGN(st->st_size - woffset);
+ }
+
+ for (;;) {
+ d = mmap(NULL, wsize, prot, MAP_SHARED, fd, woffset);
+ if (d != MAP_FAILED)