userspace: Rewrite everything

Everything.

Signed-off-by: EnderIce2 <enderice2@protonmail.com>

Userspace/libc/interpreter/alloc.c

@@ -0,0 +1,117 @@
+/*
+	This file is part of Fennix C Library.
+
+	Fennix C Library is free software: you can redistribute it and/or
+	modify it under the terms of the GNU General Public License as
+	published by the Free Software Foundation, either version 3 of
+	the License, or (at your option) any later version.
+
+	Fennix 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 General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with Fennix C Library. If not, see <https://www.gnu.org/licenses/>.
+*/
+
+#include <fennix/syscalls.h>
+#include <sys/types.h>
+#include <stdint.h>
+#include <stddef.h>
+#include <errno.h>
+
+#include "elf.h"
+#include "misc.h"
+
+typedef struct MemoryBlock
+{
+	struct MemoryBlock *next;
+	void *slots;
+	size_t slot_size;
+	size_t slots_per_block;
+	uint8_t *bitmap;
+} MemoryBlock;
+
+MemoryBlock *memory_pool = NULL;
+#define PAGE_SIZE 0x1000
+
+void *request_page(size_t size)
+{
+	size_t aligned_size = (size + PAGE_SIZE - 1) & ~(PAGE_SIZE - 1);
+	void *addr = (void *)call_mmap(NULL, aligned_size, __SYS_PROT_READ | __SYS_PROT_WRITE, __SYS_MAP_ANONYMOUS | __SYS_MAP_PRIVATE, -1, 0);
+	if ((intptr_t)addr < 0)
+		return NULL;
+	return addr;
+}
+
+void free_page(void *addr, size_t size)
+{
+	size_t aligned_size = (size + PAGE_SIZE - 1) & ~(PAGE_SIZE - 1);
+	call_munmap(addr, aligned_size);
+}
+
+MemoryBlock *allocate_block(size_t slot_size)
+{
+	size_t block_size = PAGE_SIZE;
+	size_t slots_per_block = block_size / slot_size;
+	size_t bitmap_size = (slots_per_block + 7) / 8;
+
+	MemoryBlock *block = request_page(block_size);
+	if (!block)
+		return NULL;
+
+	block->slots = (void *)((uintptr_t)block + sizeof(MemoryBlock) + bitmap_size);
+	block->slot_size = slot_size;
+	block->slots_per_block = slots_per_block;
+	block->bitmap = (uint8_t *)((uintptr_t)block + sizeof(MemoryBlock));
+	memset(block->bitmap, 0, bitmap_size);
+	block->next = NULL;
+
+	return block;
+}
+
+void *mini_malloc(size_t size)
+{
+	MemoryBlock *block = memory_pool;
+	while (block)
+	{
+		for (size_t i = 0; i < block->slots_per_block; i++)
+		{
+			size_t byte = i / 8, bit = i % 8;
+			if (!(block->bitmap[byte] & (1 << bit)))
+			{
+				block->bitmap[byte] |= (1 << bit);
+				return (void *)((uintptr_t)block->slots + i * size);
+			}
+		}
+		block = block->next;
+	}
+
+	block = allocate_block(size);
+	if (!block)
+		return NULL;
+
+	block->next = memory_pool;
+	memory_pool = block;
+
+	block->bitmap[0] |= 1;
+	return block->slots;
+}
+
+void mini_free(void *ptr)
+{
+	MemoryBlock *block = memory_pool;
+	while (block)
+	{
+		if ((uintptr_t)ptr >= (uintptr_t)block->slots &&
+			(uintptr_t)ptr < (uintptr_t)block->slots + block->slots_per_block * block->slot_size)
+		{
+			size_t index = ((uintptr_t)ptr - (uintptr_t)block->slots) / block->slot_size;
+			size_t byte = index / 8, bit = index % 8;
+			block->bitmap[byte] &= ~(1 << bit);
+			return;
+		}
+		block = block->next;
+	}
+}