// Expand or shrink a chunk returned by allocate_chunk().
// The chunk is never moved.
//
// Returns 0 if fail to expand (shrink will always succeed). Returns old
// size if successful.
size_t OsMemory_adjust_chunk(address chunk_ptr, size_t new_committed_size) {
ChunkInfo* ci = get_chunk_info(chunk_ptr);
size_t old_size = ci->size;
size_t new_size = page_align_up(new_committed_size);
if (new_size <= ci->mmaped_size) {
int rv;
if (new_size < old_size) {
rv = protect_area(chunk_ptr + new_size, old_size - new_size);
} else {
rv = unprotect_area(chunk_ptr, new_size);
}
GUARANTEE(rv == 0, "mprotect must succeed");
ci->size = new_size;
return old_size;
}
new_size = page_align_up(new_size - ci->mmaped_size);
if (anon_mmap(chunk_ptr + ci->mmaped_size, new_size) == NULL) {
return 0;
}
ci->mmaped_size += new_size;
ci->size = ci->mmaped_size;
unprotect_area(chunk_ptr, ci->size);
return old_size;
}
address OsMemory_allocate_chunk(size_t initial_size,
size_t max_size, size_t alignment)
{
// make it page aligned
max_size = page_align_up(max_size);
address chunk = anon_mmap(NULL, max_size);
if (chunk == MAP_FAILED) {
return NULL;
}
GUARANTEE((juint)chunk % alignment == 0, "must be aligned");
GUARANTEE((juint)chunk % SysPageSize == 0, "must be page aligned");
size_t aligned_size = page_align_up(initial_size);
alloc_chunk(chunk, aligned_size, max_size);
if (max_size > aligned_size) {
protect_area(chunk + aligned_size, max_size - aligned_size);
}
return chunk;
}
/* 0: bad, 1: Ok */
int
check_for_ptr (char *ptr, int fd_file)
{
int res;
caddr_t addr;
/* An available area must not be busy. */
res = write (fd_file, ptr, 8);
if (res == -1) {
if (errno != EFAULT)
buggy_os ();
} else {
/* Success: this mean that the memory is already used. */
return 0; /* Don't touch. */
}
/* An available area must be usuable. */
addr = anon_mmap (ptr, pagesize, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_FIXED);
if (addr == (caddr_t) -1)
return 0;
res = setjmp (env);
if (res == 0) {
/* Now, test it. */
*(volatile char *)addr += 1;
munmap (addr, pagesize);
return 1;
} else {
SPAM2(1, "Received signal %d at addr = 0x%08x\n", res, (unsigned)addr);
munmap (addr, pagesize);
set_sig_handler ();
return 0;
}
return 1;
}
