Convert libc to C.

libc/stdlib/malloc.c

@@ -0,0 +1,142 @@
+/*******************************************************************************
+
+    Copyright(C) Jonas 'Sortie' Termansen 2011, 2012, 2013, 2014, 2015.
+
+    This file is part of the Sortix C Library.
+
+    The Sortix C Library is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or (at your
+    option) any later version.
+
+    The Sortix C Library is distributed in the hope that it will be useful, but
+    WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+    or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
+    License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
+
+    stdlib/malloc.c
+    Allocates a chunk of memory from the dynamic memory heap.
+
+*******************************************************************************/
+
+#include <errno.h>
+#include <malloc.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+
+#if defined(HEAP_NO_ASSERT)
+#define __heap_verify() ((void) 0)
+#undef assert
+#define assert(x) do { ((void) 0); } while ( 0 )
+#endif
+
+#if !defined(HEAP_GUARD_DEBUG)
+
+void* malloc(size_t original_size)
+{
+	if ( !heap_size_has_bin(original_size) )
+		return errno = ENOMEM, (void*) NULL;
+
+	// Decide how big an allocation we would like to make.
+	size_t chunk_outer_size = sizeof(struct heap_chunk) +
+	                          sizeof(struct heap_chunk_post);
+	size_t chunk_inner_size = heap_align(original_size);
+	size_t chunk_size = chunk_outer_size + chunk_inner_size;
+
+	if ( !heap_size_has_bin(chunk_size) )
+		return errno = ENOMEM, (void*) NULL;
+
+	// Decide which bins are large enough for our allocation.
+	size_t smallest_desirable_bin = heap_bin_for_allocation(chunk_size);
+	size_t smallest_desirable_bin_size = heap_size_of_bin(smallest_desirable_bin);
+	size_t desirable_bins = ~0UL << smallest_desirable_bin;
+
+	__heap_lock();
+	__heap_verify();
+
+	// Determine whether there are any bins that we can use.
+	size_t usable_bins = desirable_bins & __heap_state.bin_filled_bitmap;
+
+	// If there are no usable bins, attempt to expand the current part of the
+	// heap or create a new part.
+	if ( !usable_bins && __heap_expand_current_part(smallest_desirable_bin_size) )
+		usable_bins = desirable_bins & __heap_state.bin_filled_bitmap;
+
+	// If we failed to expand the current part or make a new one - then we are
+	// officially out of memory until someone deallocates something.
+	if ( !usable_bins )
+	{
+		__heap_verify();
+		__heap_unlock();
+		return (void*) NULL;
+	}
+
+	// Pick the smallest of the usable bins.
+	size_t bin_index = heap_bsf(usable_bins);
+
+	// Pick the first element of this bins linked list. This is our allocation.
+	struct heap_chunk* result_chunk = __heap_state.bin[bin_index];
+	assert(result_chunk);
+	assert(HEAP_IS_POINTER_ALIGNED(result_chunk, result_chunk->chunk_size));
+
+	assert(chunk_size <= result_chunk->chunk_size);
+
+	// Mark our chosen chunk as used and remove it from its bin.
+	heap_remove_chunk(result_chunk);
+
+	// If our chunk is larger than what we really needed and it is possible to
+	// split the chunk into two, then we should split off a part of it and
+	// return it to the heap for further allocation.
+	if ( heap_can_split_chunk(result_chunk, chunk_size) )
+		heap_split_chunk(result_chunk, chunk_size);
+
+	__heap_verify();
+	__heap_unlock();
+
+	// Return the inner data associated with the chunk to the caller.
+	return heap_chunk_to_data(result_chunk);
+}
+
+#else
+
+#include <sys/mman.h>
+
+#ifdef __is_sortix_libk
+#include <libk.h>
+#endif
+
+void* malloc(size_t original_size)
+{
+	if ( !original_size )
+		original_size = 1;
+	size_t size = -(-original_size & ~15UL);
+	size_t needed = 16 + size;
+	needed = HEAP_ALIGN_PAGEUP(needed);
+	size_t virtsize = needed + HEAP_PAGE_SIZE;
+#ifdef __is_sortix_libk
+	void* from = libk_mmap(virtsize, PROT_KREAD | PROT_KWRITE);
+#else
+	void* from = mmap(NULL, virtsize, PROT_READ | PROT_WRITE,
+	                  MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+#endif
+	if ( from == MAP_FAILED )
+		return NULL;
+	void* guard = (char*) from + needed;
+#ifdef __is_sortix_libk
+	libk_mprotect(guard, HEAP_PAGE_SIZE, PROT_NONE);
+#else
+	if ( mprotect(guard, HEAP_PAGE_SIZE, PROT_NONE) < 0 )
+		return munmap(from, virtsize), (void*) NULL;
+#endif
+	struct heap_alloc* addralloc_ptr = (struct heap_alloc*) from;
+	addralloc_ptr->from = (uintptr_t) from;
+	addralloc_ptr->size = virtsize;
+	size_t offset = needed - size;
+	return (void*) (addralloc_ptr->from + offset);
+}
+
+#endif