diff --git a/kernel/include/kernel/FS/Inode.h b/kernel/include/kernel/FS/Inode.h index f722b12e..46d469a2 100644 --- a/kernel/include/kernel/FS/Inode.h +++ b/kernel/include/kernel/FS/Inode.h @@ -3,6 +3,7 @@ #include #include #include +#include #include #include @@ -17,6 +18,9 @@ namespace Kernel using namespace API; + class FileBackedRegion; + class SharedFileData; + class Inode : public BAN::RefCounted { public: @@ -112,6 +116,9 @@ namespace Kernel private: mutable RecursiveSpinLock m_lock; + + BAN::WeakPtr m_shared_region; + friend class FileBackedRegion; }; } \ No newline at end of file diff --git a/kernel/include/kernel/Memory/FileBackedRegion.h b/kernel/include/kernel/Memory/FileBackedRegion.h index b2d0df94..b7decd8d 100644 --- a/kernel/include/kernel/Memory/FileBackedRegion.h +++ b/kernel/include/kernel/Memory/FileBackedRegion.h @@ -6,6 +6,17 @@ namespace Kernel { + struct SharedFileData : public BAN::RefCounted, public BAN::Weakable + { + ~SharedFileData(); + + // FIXME: this should probably be ordered tree like map + // for fast lookup and less memory usage + BAN::Vector pages; + BAN::RefPtr inode; + uint8_t page_buffer[PAGE_SIZE]; + }; + class FileBackedRegion final : public MemoryRegion { BAN_NON_COPYABLE(FileBackedRegion); @@ -25,6 +36,8 @@ namespace Kernel private: BAN::RefPtr m_inode; const off_t m_offset; + + BAN::RefPtr m_shared_data; }; } \ No newline at end of file diff --git a/kernel/kernel/Memory/FileBackedRegion.cpp b/kernel/kernel/Memory/FileBackedRegion.cpp index f4bdb802..086c9d62 100644 --- a/kernel/kernel/Memory/FileBackedRegion.cpp +++ b/kernel/kernel/Memory/FileBackedRegion.cpp @@ -9,9 +9,6 @@ namespace Kernel { ASSERT(inode->mode().ifreg()); - if (type != Type::PRIVATE) - return BAN::Error::from_errno(ENOTSUP); - if (offset < 0 || offset % PAGE_SIZE || size == 0) return BAN::Error::from_errno(EINVAL); if (size > (size_t)inode->size() || (size_t)offset > (size_t)inode->size() - size) @@ -24,6 +21,21 @@ namespace Kernel TRY(region->initialize(address_range)); + if (type == Type::SHARED) + { + LockGuard _(inode->m_lock); + if (inode->m_shared_region.valid()) + region->m_shared_data = inode->m_shared_region.lock(); + else + { + auto shared_data = TRY(BAN::RefPtr::create()); + TRY(shared_data->pages.resize(BAN::Math::div_round_up(inode->size(), PAGE_SIZE))); + shared_data->inode = inode; + inode->m_shared_region = TRY(shared_data->get_weak_ptr()); + region->m_shared_data = BAN::move(shared_data); + } + } + return region; } @@ -38,8 +50,9 @@ namespace Kernel { if (m_vaddr == 0) return; - - ASSERT(m_type == Type::PRIVATE); + + if (m_type == Type::SHARED) + return; size_t needed_pages = BAN::Math::div_round_up(m_size, PAGE_SIZE); for (size_t i = 0; i < needed_pages; i++) @@ -50,10 +63,30 @@ namespace Kernel } } + SharedFileData::~SharedFileData() + { + for (size_t i = 0; i < pages.size(); i++) + { + if (pages[i] == 0) + continue; + + { + auto& page_table = PageTable::current(); + LockGuard _(page_table); + ASSERT(page_table.is_page_free(0)); + + page_table.map_page_at(pages[i], 0, PageTable::Flags::Present); + memcpy(page_buffer, (void*)0, PAGE_SIZE); + page_table.unmap_page(0); + } + + if (auto ret = inode->write(i * PAGE_SIZE, page_buffer, PAGE_SIZE); ret.is_error()) + dwarnln("{}", ret.error()); + } + } + BAN::ErrorOr FileBackedRegion::allocate_page_containing(vaddr_t address) { - ASSERT(m_type == Type::PRIVATE); - ASSERT(contains(address)); // Check if address is already mapped @@ -61,44 +94,89 @@ namespace Kernel if (m_page_table.physical_address_of(vaddr) != 0) return false; - // Map new physcial page to address - paddr_t paddr = Heap::get().take_free_page(); - if (paddr == 0) - return BAN::Error::from_errno(ENOMEM); - m_page_table.map_page_at(paddr, vaddr, m_flags); + if (m_type == Type::PRIVATE) + { + // Map new physcial page to address + paddr_t paddr = Heap::get().take_free_page(); + if (paddr == 0) + return BAN::Error::from_errno(ENOMEM); + m_page_table.map_page_at(paddr, vaddr, m_flags); - size_t file_offset = m_offset + (vaddr - m_vaddr); - size_t bytes = BAN::Math::min(m_size - file_offset, PAGE_SIZE); + size_t file_offset = m_offset + (vaddr - m_vaddr); + size_t bytes = BAN::Math::min(m_size - file_offset, PAGE_SIZE); - BAN::ErrorOr read_ret = 0; + BAN::ErrorOr read_ret = 0; - // Zero out the new page - if (&PageTable::current() == &m_page_table) - read_ret = m_inode->read(file_offset, (void*)vaddr, bytes); + // Zero out the new page + if (&PageTable::current() == &m_page_table) + read_ret = m_inode->read(file_offset, (void*)vaddr, bytes); + else + { + auto& page_table = PageTable::current(); + + LockGuard _(page_table); + ASSERT(page_table.is_page_free(0)); + + page_table.map_page_at(paddr, 0, PageTable::Flags::ReadWrite | PageTable::Flags::Present); + read_ret = m_inode->read(file_offset, (void*)0, bytes); + memset((void*)0, 0x00, PAGE_SIZE); + page_table.unmap_page(0); + } + + if (read_ret.is_error()) + { + Heap::get().release_page(paddr); + m_page_table.unmap_page(vaddr); + return read_ret.release_error(); + } + + if (read_ret.value() < bytes) + { + dwarnln("Only {}/{} bytes read", read_ret.value(), bytes); + Heap::get().release_page(paddr); + m_page_table.unmap_page(vaddr); + return BAN::Error::from_errno(EIO); + } + } + else if (m_type == Type::SHARED) + { + LockGuard _(m_inode->m_lock); + ASSERT(m_inode->m_shared_region.valid()); + ASSERT(m_shared_data->pages.size() == BAN::Math::div_round_up(m_inode->size(), PAGE_SIZE)); + + auto& pages = m_shared_data->pages; + size_t page_index = (vaddr - m_vaddr) / PAGE_SIZE; + + if (pages[page_index] == 0) + { + pages[page_index] = Heap::get().take_free_page(); + if (pages[page_index] == 0) + return BAN::Error::from_errno(ENOMEM); + + size_t offset = vaddr - m_vaddr; + size_t bytes = BAN::Math::min(m_size - offset, PAGE_SIZE); + + TRY(m_inode->read(offset, m_shared_data->page_buffer, bytes)); + + auto& page_table = PageTable::current(); + + // TODO: check if this can cause deadlock? + LockGuard page_table_lock(page_table); + ASSERT(page_table.is_page_free(0)); + + page_table.map_page_at(pages[page_index], 0, PageTable::Flags::ReadWrite | PageTable::Flags::Present); + memcpy((void*)0, m_shared_data->page_buffer, PAGE_SIZE); + page_table.unmap_page(0); + } + + paddr_t paddr = pages[page_index]; + ASSERT(paddr); + + m_page_table.map_page_at(paddr, vaddr, m_flags); + } else { - LockGuard _(PageTable::current()); - ASSERT(PageTable::current().is_page_free(0)); - - PageTable::current().map_page_at(paddr, 0, PageTable::Flags::ReadWrite | PageTable::Flags::Present); - read_ret = m_inode->read(file_offset, (void*)0, bytes); - memset((void*)0, 0x00, PAGE_SIZE); - PageTable::current().unmap_page(0); - } - - if (read_ret.is_error()) - { - Heap::get().release_page(paddr); - m_page_table.unmap_page(vaddr); - return read_ret.release_error(); - } - - if (read_ret.value() < bytes) - { - dwarnln("Only {}/{} bytes read", read_ret.value(), bytes); - Heap::get().release_page(paddr); - m_page_table.unmap_page(vaddr); - return BAN::Error::from_errno(EIO); + ASSERT_NOT_REACHED(); } return true; diff --git a/kernel/kernel/Process.cpp b/kernel/kernel/Process.cpp index f6df4a6e..507f5fed 100644 --- a/kernel/kernel/Process.cpp +++ b/kernel/kernel/Process.cpp @@ -863,7 +863,7 @@ namespace Kernel if (!(inode_flags & O_RDONLY)) return BAN::Error::from_errno(EACCES); if (region_type == MemoryRegion::Type::SHARED) - if (!(args->prot & PROT_WRITE) || !(inode_flags & O_WRONLY)) + if ((args->prot & PROT_WRITE) && !(inode_flags & O_WRONLY)) return BAN::Error::from_errno(EACCES); auto region = TRY(FileBackedRegion::create(