serenity/Kernel/FileDescriptor.cpp
2019-01-31 17:31:23 +01:00

321 lines
7.9 KiB
C++

#include "FileDescriptor.h"
#include "FileSystem.h"
#include "CharacterDevice.h"
#include <LibC/errno_numbers.h>
#include "UnixTypes.h"
#include <AK/BufferStream.h>
#include "FIFO.h"
#include "TTY.h"
#include "MasterPTY.h"
RetainPtr<FileDescriptor> FileDescriptor::create(RetainPtr<Inode>&& inode)
{
return adopt(*new FileDescriptor(move(inode)));
}
RetainPtr<FileDescriptor> FileDescriptor::create(RetainPtr<CharacterDevice>&& device)
{
return adopt(*new FileDescriptor(move(device)));
}
RetainPtr<FileDescriptor> FileDescriptor::create_pipe_writer(FIFO& fifo)
{
return adopt(*new FileDescriptor(fifo, FIFO::Writer));
}
RetainPtr<FileDescriptor> FileDescriptor::create_pipe_reader(FIFO& fifo)
{
return adopt(*new FileDescriptor(fifo, FIFO::Reader));
}
FileDescriptor::FileDescriptor(RetainPtr<Inode>&& inode)
: m_inode(move(inode))
{
}
FileDescriptor::FileDescriptor(RetainPtr<CharacterDevice>&& device)
: m_device(move(device))
{
}
FileDescriptor::~FileDescriptor()
{
if (m_device) {
m_device->close();
m_device = nullptr;
}
if (m_fifo) {
m_fifo->close(fifo_direction());
m_fifo = nullptr;
}
m_inode = nullptr;
}
RetainPtr<FileDescriptor> FileDescriptor::clone()
{
RetainPtr<FileDescriptor> descriptor;
if (is_fifo()) {
descriptor = fifo_direction() == FIFO::Reader
? FileDescriptor::create_pipe_reader(*m_fifo)
: FileDescriptor::create_pipe_writer(*m_fifo);
} else {
if (m_device) {
descriptor = FileDescriptor::create(m_device.copy_ref());
descriptor->m_inode = m_inode.copy_ref();
} else {
descriptor = FileDescriptor::create(m_inode.copy_ref());
}
}
if (!descriptor)
return nullptr;
descriptor->m_current_offset = m_current_offset;
descriptor->m_is_blocking = m_is_blocking;
descriptor->m_file_flags = m_file_flags;
return descriptor;
}
bool addition_would_overflow(off_t a, off_t b)
{
ASSERT(a > 0);
uint64_t ua = a;
return (ua + b) > maxFileOffset;
}
int FileDescriptor::fstat(stat* buffer)
{
ASSERT(!is_fifo());
if (!m_inode && !m_device)
return -EBADF;
auto metadata = this->metadata();
if (!metadata.is_valid())
return -EIO;
buffer->st_dev = encoded_device(metadata.major_device, metadata.minor_device);
buffer->st_ino = metadata.inode.index();
buffer->st_mode = metadata.mode;
buffer->st_nlink = metadata.link_count;
buffer->st_uid = metadata.uid;
buffer->st_gid = metadata.gid;
buffer->st_rdev = 0; // FIXME
buffer->st_size = metadata.size;
buffer->st_blksize = metadata.block_size;
buffer->st_blocks = metadata.block_count;
buffer->st_atime = metadata.atime;
buffer->st_mtime = metadata.mtime;
buffer->st_ctime = metadata.ctime;
return 0;
}
off_t FileDescriptor::seek(off_t offset, int whence)
{
ASSERT(!is_fifo());
if (!m_inode && !m_device)
return -EBADF;
// FIXME: The file type should be cached on the vnode.
// It's silly that we have to do a full metadata lookup here.
auto metadata = this->metadata();
if (!metadata.is_valid())
return -EIO;
if (metadata.is_socket() || metadata.is_fifo())
return -ESPIPE;
off_t newOffset;
switch (whence) {
case SEEK_SET:
newOffset = offset;
break;
case SEEK_CUR:
newOffset = m_current_offset + offset;
if (newOffset < 0)
return -EINVAL;
break;
case SEEK_END:
ASSERT(metadata.size); // FIXME: What do I do?
newOffset = metadata.size;
break;
default:
return -EINVAL;
}
m_current_offset = newOffset;
return m_current_offset;
}
ssize_t FileDescriptor::read(Process& process, byte* buffer, size_t count)
{
if (is_fifo()) {
ASSERT(fifo_direction() == FIFO::Reader);
return m_fifo->read(buffer, count);
}
if (m_device) {
// FIXME: What should happen to m_currentOffset?
return m_device->read(process, buffer, count);
}
ASSERT(inode());
ssize_t nread = inode()->read_bytes(m_current_offset, count, buffer, this);
m_current_offset += nread;
return nread;
}
ssize_t FileDescriptor::write(Process& process, const byte* data, size_t size)
{
if (is_fifo()) {
ASSERT(fifo_direction() == FIFO::Writer);
return m_fifo->write(data, size);
}
if (m_device) {
// FIXME: What should happen to m_currentOffset?
return m_device->write(process, data, size);
}
ASSERT(m_inode);
ssize_t nwritten = m_inode->write_bytes(m_current_offset, size, data, this);
m_current_offset += nwritten;
return nwritten;
}
bool FileDescriptor::can_write(Process& process)
{
if (is_fifo()) {
ASSERT(fifo_direction() == FIFO::Writer);
return m_fifo->can_write();
}
if (m_device)
return m_device->can_write(process);
return true;
}
bool FileDescriptor::can_read(Process& process)
{
if (is_fifo()) {
ASSERT(fifo_direction() == FIFO::Reader);
return m_fifo->can_read();
}
if (m_device)
return m_device->can_read(process);
return true;
}
ByteBuffer FileDescriptor::read_entire_file(Process& process)
{
ASSERT(!is_fifo());
if (m_device) {
auto buffer = ByteBuffer::create_uninitialized(1024);
ssize_t nread = m_device->read(process, buffer.pointer(), buffer.size());
buffer.trim(nread);
return buffer;
}
ASSERT(m_inode);
return m_inode->read_entire(this);
}
bool FileDescriptor::is_directory() const
{
ASSERT(!is_fifo());
return metadata().is_directory();
}
ssize_t FileDescriptor::get_dir_entries(byte* buffer, size_t size)
{
auto metadata = this->metadata();
if (!metadata.is_valid())
return -EIO;
if (!metadata.is_directory())
return -ENOTDIR;
// FIXME: Compute the actual size needed.
auto temp_buffer = ByteBuffer::create_uninitialized(2048);
BufferStream stream(temp_buffer);
VFS::the().traverse_directory_inode(*m_inode, [&stream] (auto& entry) {
stream << (dword)entry.inode.index();
stream << (byte)entry.file_type;
stream << (dword)entry.name_length;
stream << entry.name;
return true;
});
if (size < stream.offset())
return -1;
memcpy(buffer, temp_buffer.pointer(), stream.offset());
return stream.offset();
}
bool FileDescriptor::is_tty() const
{
return m_device && m_device->is_tty();
}
const TTY* FileDescriptor::tty() const
{
if (!is_tty())
return nullptr;
return static_cast<const TTY*>(m_device.ptr());
}
TTY* FileDescriptor::tty()
{
if (!is_tty())
return nullptr;
return static_cast<TTY*>(m_device.ptr());
}
bool FileDescriptor::is_master_pty() const
{
if (m_device)
return m_device->is_master_pty();
return false;
}
const MasterPTY* FileDescriptor::master_pty() const
{
if (!is_master_pty())
return nullptr;
return static_cast<const MasterPTY*>(m_device.ptr());
}
MasterPTY* FileDescriptor::master_pty()
{
if (!is_master_pty())
return nullptr;
return static_cast<MasterPTY*>(m_device.ptr());
}
int FileDescriptor::close()
{
return 0;
}
String FileDescriptor::absolute_path()
{
Stopwatch sw("absolute_path");
if (is_tty())
return tty()->tty_name();
if (is_fifo())
return String::format("fifo:%x", m_fifo.ptr());
if (is_character_device())
return String::format("device:%u,%u (%s)", m_device->major(), m_device->minor(), m_device->class_name());
ASSERT(m_inode);
return VFS::the().absolute_path(*m_inode);
}
FileDescriptor::FileDescriptor(FIFO& fifo, FIFO::Direction direction)
: m_is_blocking(true)
, m_fifo(fifo)
, m_fifo_direction(direction)
{
m_fifo->open(direction);
}
InodeMetadata FileDescriptor::metadata() const
{
if (m_inode)
return m_inode->metadata();
return { };
}