diff options
Diffstat (limited to 'LibC/stdlib.cpp')
-rw-r--r-- | LibC/stdlib.cpp | 172 |
1 files changed, 0 insertions, 172 deletions
diff --git a/LibC/stdlib.cpp b/LibC/stdlib.cpp index 656bd91ca7..17486f7c25 100644 --- a/LibC/stdlib.cpp +++ b/LibC/stdlib.cpp @@ -16,178 +16,6 @@ extern "C" { -#define MALLOC_SCRUB_BYTE 0x85 -#define FREE_SCRUB_BYTE 0x82 - -struct MallocHeader { - uint16_t first_chunk_index; - uint16_t chunk_count : 15; - bool is_mmap : 1; - size_t size; -}; - -#define CHUNK_SIZE 32 -#define POOL_SIZE 4 * 1048576 - -static const size_t malloc_budget = POOL_SIZE; -static byte s_malloc_map[POOL_SIZE / CHUNK_SIZE / 8]; -static byte* s_malloc_pool; - -static uint32_t s_malloc_sum_alloc = 0; -static uint32_t s_malloc_sum_free = POOL_SIZE; - -static bool s_log_malloc = false; -static bool s_scrub_malloc = true; -static bool s_scrub_free = true; - -void* malloc(size_t size) -{ - if (s_log_malloc) - dbgprintf("LibC: malloc(%u)\n", size); - - if (size == 0) - return nullptr; - - // We need space for the MallocHeader structure at the head of the block. - size_t real_size = size + sizeof(MallocHeader); - - if (real_size >= PAGE_SIZE) { - auto* memory = mmap(nullptr, real_size, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0); - if (memory == MAP_FAILED) { - fprintf(stderr, "malloc() failed to mmap() for a %u-byte allocation: %s", size, strerror(errno)); - volatile char* crashme = (char*)0xf007d00d; - *crashme = 0; - return nullptr; - } - auto* header = (MallocHeader*)(memory); - byte* ptr = ((byte*)header) + sizeof(MallocHeader); - header->chunk_count = 0; - header->first_chunk_index = 0; - header->size = real_size; - header->is_mmap = true; - return ptr; - } - - if (s_malloc_sum_free < real_size) { - fprintf(stderr, "malloc(): Out of memory\ns_malloc_sum_free=%u, real_size=%u\n", s_malloc_sum_free, real_size); - ASSERT_NOT_REACHED(); - } - - size_t chunks_needed = real_size / CHUNK_SIZE; - if (real_size % CHUNK_SIZE) - chunks_needed++; - - size_t chunks_here = 0; - size_t first_chunk = 0; - - for (unsigned i = 0; i < (POOL_SIZE / CHUNK_SIZE / 8); ++i) { - if (s_malloc_map[i] == 0xff) { - // Skip over completely full bucket. - chunks_here = 0; - continue; - } - - // FIXME: This scan can be optimized further with TZCNT. - for (unsigned j = 0; j < 8; ++j) { - if ((s_malloc_map[i] & (1<<j))) { - // This is in use, so restart chunks_here counter. - chunks_here = 0; - continue; - } - if (chunks_here == 0) { - // Mark where potential allocation starts. - first_chunk = i * 8 + j; - } - - ++chunks_here; - - if (chunks_here == chunks_needed) { - auto* header = (MallocHeader*)(s_malloc_pool + (first_chunk * CHUNK_SIZE)); - byte* ptr = ((byte*)header) + sizeof(MallocHeader); - header->chunk_count = chunks_needed; - header->first_chunk_index = first_chunk; - header->is_mmap = false; - header->size = size; - - for (size_t k = first_chunk; k < (first_chunk + chunks_needed); ++k) - s_malloc_map[k / 8] |= 1 << (k % 8); - - s_malloc_sum_alloc += header->chunk_count * CHUNK_SIZE; - s_malloc_sum_free -= header->chunk_count * CHUNK_SIZE; - - if (s_scrub_malloc) - memset(ptr, MALLOC_SCRUB_BYTE, (header->chunk_count * CHUNK_SIZE) - sizeof(MallocHeader)); - return ptr; - } - } - } - - fprintf(stderr, "malloc(): Out of memory (no consecutive chunks found for size %u)\n", size); - volatile char* crashme = (char*)0xc007d00d; - *crashme = 0; - return nullptr; -} - -void free(void* ptr) -{ - if (!ptr) - return; - - auto* header = (MallocHeader*)((((byte*)ptr) - sizeof(MallocHeader))); - if (header->is_mmap) { - int rc = munmap(header, header->size); - if (rc < 0) - fprintf(stderr, "free(): munmap(%p) for allocation %p with size %u failed: %s\n", header, ptr, header->size, strerror(errno)); - return; - } - - for (int i = header->first_chunk_index; i < (header->first_chunk_index + header->chunk_count); ++i) - s_malloc_map[i / 8] &= ~(1 << (i % 8)); - - s_malloc_sum_alloc -= header->chunk_count * CHUNK_SIZE; - s_malloc_sum_free += header->chunk_count * CHUNK_SIZE; - - if (s_scrub_free) - memset(header, FREE_SCRUB_BYTE, header->chunk_count * CHUNK_SIZE); -} - -void __malloc_init() -{ - s_malloc_pool = (byte*)mmap(nullptr, malloc_budget, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0); - int rc = set_mmap_name(s_malloc_pool, malloc_budget, "malloc pool"); - if (rc < 0) - perror("set_mmap_name failed"); - - if (getenv("LIBC_NOSCRUB_MALLOC")) - s_scrub_malloc = false; - if (getenv("LIBC_NOSCRUB_FREE")) - s_scrub_free = false; - if (getenv("LIBC_LOG_MALLOC")) - s_log_malloc = true; -} - -void* calloc(size_t count, size_t size) -{ - size_t new_size = count * size; - auto* ptr = malloc(new_size); - memset(ptr, 0, new_size); - return ptr; -} - -void* realloc(void *ptr, size_t size) -{ - if (!ptr) - return malloc(size); - auto* header = (MallocHeader*)((((byte*)ptr) - sizeof(MallocHeader))); - size_t old_size = header->size; - if (size == old_size) - return ptr; - auto* new_ptr = malloc(size); - memcpy(new_ptr, ptr, min(old_size, size)); - free(ptr); - return new_ptr; -} - typedef void(*__atexit_handler)(); static int __atexit_handler_count = 0; static __atexit_handler __atexit_handlers[32]; |