-struct lizard_buffer *
-lizard_alloc(uns max_len)
-{
- int fd = open("/dev/zero", O_RDWR);
- if (fd < 0)
- die("open(/dev/zero): %m");
- struct lizard_buffer *buf = xmalloc(sizeof(struct lizard_buffer));
- buf->len = (max_len + 2*PAGE_SIZE - 1) / PAGE_SIZE * PAGE_SIZE;
- buf->ptr = mmap(NULL, buf->len, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
- if (buf->ptr == MAP_FAILED)
- die("mmap(/dev/zero): %m");
- return buf;
-}
-
-void
-lizard_free(struct lizard_buffer *buf)
-{
- munmap(buf->ptr, buf->len);
- xfree(buf);
-}
-
-int
-lizard_decompress_safe(byte *in, struct lizard_buffer *buf, uns expected_length)
- /* Decompresses into buf->ptr and returns the length of the uncompressed
- * file. Negative return values signalise errors. If something goes wrong
- * and buffer would overflow, SIGSEGV is raised. */
-{
- uns lock_offset = (expected_length + PAGE_SIZE - 1) / PAGE_SIZE * PAGE_SIZE;
- if (lock_offset + PAGE_SIZE > buf->len)
- return -1;
- mprotect(buf->ptr, lock_offset, PROT_READ | PROT_WRITE);
- mprotect(buf->ptr + lock_offset, PAGE_SIZE, PROT_READ);
- return lizard_decompress(in, buf->ptr);
-}
-