mirror of
https://github.com/RGBCube/serenity
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d3e8eb5918
This allows sys$mprotect() to honor the original readable & writable flags of the open file description as they were at the point we did the original sys$mmap(). IIUC, this is what Dr. POSIX wants us to do: https://pubs.opengroup.org/onlinepubs/9699919799/functions/mprotect.html Also, remove the bogus and racy "W^X" checking we did against mappings based on their current inode metadata. If we want to do this, we can do it properly. For now, it was not only racy, but also did blocking I/O while holding a spinlock.
99 lines
2.4 KiB
C++
99 lines
2.4 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <Kernel/FileSystem/Inode.h>
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#include <Kernel/Memory/InodeVMObject.h>
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namespace Kernel::Memory {
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InodeVMObject::InodeVMObject(Inode& inode, FixedArray<LockRefPtr<PhysicalPage>>&& new_physical_pages, Bitmap dirty_pages)
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: VMObject(move(new_physical_pages))
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, m_inode(inode)
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, m_dirty_pages(move(dirty_pages))
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{
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}
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InodeVMObject::InodeVMObject(InodeVMObject const& other, FixedArray<LockRefPtr<PhysicalPage>>&& new_physical_pages, Bitmap dirty_pages)
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: VMObject(move(new_physical_pages))
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, m_inode(other.m_inode)
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, m_dirty_pages(move(dirty_pages))
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{
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for (size_t i = 0; i < page_count(); ++i)
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m_dirty_pages.set(i, other.m_dirty_pages.get(i));
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}
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InodeVMObject::~InodeVMObject() = default;
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size_t InodeVMObject::amount_clean() const
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{
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size_t count = 0;
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VERIFY(page_count() == m_dirty_pages.size());
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for (size_t i = 0; i < page_count(); ++i) {
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if (!m_dirty_pages.get(i) && m_physical_pages[i])
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++count;
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}
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return count * PAGE_SIZE;
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}
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size_t InodeVMObject::amount_dirty() const
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{
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size_t count = 0;
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for (size_t i = 0; i < m_dirty_pages.size(); ++i) {
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if (m_dirty_pages.get(i))
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++count;
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}
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return count * PAGE_SIZE;
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}
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int InodeVMObject::release_all_clean_pages()
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{
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SpinlockLocker locker(m_lock);
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int count = 0;
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for (size_t i = 0; i < page_count(); ++i) {
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if (!m_dirty_pages.get(i) && m_physical_pages[i]) {
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m_physical_pages[i] = nullptr;
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++count;
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}
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}
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if (count) {
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for_each_region([](auto& region) {
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region.remap();
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});
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}
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return count;
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}
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int InodeVMObject::try_release_clean_pages(int page_amount)
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{
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SpinlockLocker locker(m_lock);
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int count = 0;
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for (size_t i = 0; i < page_count() && count < page_amount; ++i) {
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if (!m_dirty_pages.get(i) && m_physical_pages[i]) {
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m_physical_pages[i] = nullptr;
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++count;
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}
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}
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if (count) {
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for_each_region([](auto& region) {
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region.remap();
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});
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}
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return count;
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}
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u32 InodeVMObject::writable_mappings() const
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{
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u32 count = 0;
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const_cast<InodeVMObject&>(*this).for_each_region([&](auto& region) {
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if (region.is_writable())
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++count;
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});
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return count;
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}
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}
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