Restructured and rewritten entire codebase

core/memory/brk.cpp

@@ -0,0 +1,94 @@
+/*
+	This file is part of Fennix Kernel.
+
+	Fennix Kernel 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 Kernel 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 Kernel. If not, see <https://www.gnu.org/licenses/>.
+*/
+
+#include <memory/brk.hpp>
+#include <memory/virtual.hpp>
+#include <memory/vma.hpp>
+#include <assert.h>
+#include <errno.h>
+#include <debug.h>
+
+namespace Memory
+{
+	void *ProgramBreak::brk(void *Address)
+	{
+		if (HeapStart == 0x0 || Break == 0x0)
+		{
+			error("HeapStart or Break is 0x0");
+			return (void *)-EAGAIN;
+		}
+
+		/* Get the current program break. */
+		if (Address == nullptr)
+			return (void *)Break;
+
+		/* Check if the address is valid. */
+		if ((uintptr_t)Address < HeapStart)
+			return (void *)-ENOMEM;
+
+		Virtual vmm = Virtual(this->Table);
+
+		if ((uintptr_t)Address > Break)
+		{
+			/* Allocate more memory. */
+			size_t Pages = TO_PAGES(uintptr_t(Address) - Break);
+			void *Allocated = vma->RequestPages(Pages);
+			if (Allocated == nullptr)
+				return (void *)-ENOMEM;
+
+			/* Map the allocated pages. */
+			for (size_t i = 0; i < Pages; i++)
+			{
+				void *VirtAddr = (void *)(Break + (i * PAGE_SIZE));
+				void *PhysAddr = (void *)(uintptr_t(Allocated) + (i * PAGE_SIZE));
+				vmm.Map(VirtAddr, PhysAddr, RW | US);
+			}
+
+			Break = (uint64_t)Address;
+			return (void *)Break;
+		}
+
+		/* Free memory. */
+		size_t Pages = TO_PAGES(uintptr_t(Address) - Break);
+		vma->FreePages((void *)Break, Pages);
+
+		/* Unmap the freed pages. */
+		for (size_t i = 0; i < Pages; i++)
+		{
+			uint64_t Page = Break - (i * 0x1000);
+			vmm.Remap((void *)Page, (void *)Page, PTFlag::P | PTFlag::RW);
+		}
+
+		Break = (uint64_t)Address;
+		return (void *)Break;
+	}
+
+	ProgramBreak::ProgramBreak(PageTable *Table, VirtualMemoryArea *vma)
+	{
+		assert(Table != nullptr);
+		assert(vma != nullptr);
+
+		this->Table = Table;
+		this->vma = vma;
+	}
+
+	ProgramBreak::~ProgramBreak()
+	{
+		/* Do nothing because VirtualMemoryArea
+			will be destroyed later. */
+	}
+}