Trait FileOps 

pub trait FileOps:
    Send
    + Sync
    + AsAny
    + 'static {
    // Required methods
    fn is_seekable(&self) -> bool;
    fn read(
        &self,
        locked: &mut Locked<FileOpsCore>,
        file: &FileObject,
        current_task: &CurrentTask,
        offset: usize,
        data: &mut dyn OutputBuffer,
    ) -> Result<usize, Errno>;
    fn write(
        &self,
        locked: &mut Locked<FileOpsCore>,
        file: &FileObject,
        current_task: &CurrentTask,
        offset: usize,
        data: &mut dyn InputBuffer,
    ) -> Result<usize, Errno>;
    fn seek(
        &self,
        locked: &mut Locked<FileOpsCore>,
        file: &FileObject,
        current_task: &CurrentTask,
        current_offset: off_t,
        target: SeekTarget,
    ) -> Result<off_t, Errno>;
    fn sync(
        &self,
        file: &FileObject,
        _current_task: &CurrentTask,
    ) -> Result<(), Errno>;

    // Provided methods
    fn open(
        &self,
        _locked: &mut Locked<FileOpsCore>,
        _file: &FileObject,
        _current_task: &CurrentTask,
    ) -> Result<(), Errno> { ... }
    fn close(
        self: Box<Self>,
        _locked: &mut Locked<FileOpsCore>,
        _file: &FileObjectState,
        _current_task: &CurrentTask,
    ) { ... }
    fn flush(
        &self,
        _locked: &mut Locked<FileOpsCore>,
        _file: &FileObject,
        _current_task: &CurrentTask,
    ) { ... }
    fn has_persistent_offsets(&self) -> bool { ... }
    fn writes_update_seek_offset(&self) -> bool { ... }
    fn data_sync(
        &self,
        file: &FileObject,
        current_task: &CurrentTask,
    ) -> Result<(), Errno> { ... }
    fn get_memory(
        &self,
        _locked: &mut Locked<FileOpsCore>,
        _file: &FileObject,
        _current_task: &CurrentTask,
        _length: Option<usize>,
        _prot: ProtectionFlags,
    ) -> Result<Arc<MemoryObject>, Errno> { ... }
    fn mmap(
        &self,
        locked: &mut Locked<FileOpsCore>,
        file: &FileObject,
        current_task: &CurrentTask,
        addr: DesiredAddress,
        memory_offset: u64,
        length: usize,
        prot_flags: ProtectionFlags,
        options: MappingOptions,
        filename: NamespaceNode,
    ) -> Result<UserAddress, Errno> { ... }
    fn readdir(
        &self,
        _locked: &mut Locked<FileOpsCore>,
        _file: &FileObject,
        _current_task: &CurrentTask,
        _sink: &mut dyn DirentSink,
    ) -> Result<(), Errno> { ... }
    fn wait_async(
        &self,
        _locked: &mut Locked<FileOpsCore>,
        _file: &FileObject,
        _current_task: &CurrentTask,
        _waiter: &Waiter,
        _events: FdEvents,
        _handler: EventHandler,
    ) -> Option<WaitCanceler> { ... }
    fn query_events(
        &self,
        _locked: &mut Locked<FileOpsCore>,
        _file: &FileObject,
        _current_task: &CurrentTask,
    ) -> Result<FdEvents, Errno> { ... }
    fn ioctl(
        &self,
        locked: &mut Locked<Unlocked>,
        file: &FileObject,
        current_task: &CurrentTask,
        request: u32,
        arg: SyscallArg,
    ) -> Result<SyscallResult, Errno> { ... }
    fn fcntl(
        &self,
        _file: &FileObject,
        _current_task: &CurrentTask,
        cmd: u32,
        _arg: u64,
    ) -> Result<SyscallResult, Errno> { ... }
    fn to_handle(
        &self,
        file: &FileObject,
        current_task: &CurrentTask,
    ) -> Result<Option<NullableHandle>, Errno> { ... }
    fn as_thread_group_key(
        &self,
        _file: &FileObject,
    ) -> Result<ThreadGroupKey, Errno> { ... }
    fn readahead(
        &self,
        _file: &FileObject,
        _current_task: &CurrentTask,
        _offset: usize,
        _length: usize,
    ) -> Result<(), Errno> { ... }
    fn extra_fdinfo(
        &self,
        _locked: &mut Locked<FileOpsCore>,
        _file: &FileHandle,
        _current_task: &CurrentTask,
    ) -> Option<FsString> { ... }
}

Corresponds to struct file_operations in Linux, plus any filesystem-specific data.

Required Methods

fn is_seekable(&self) -> bool

Returns whether the file is seekable.

fn read( &self, locked: &mut Locked<FileOpsCore>, file: &FileObject, current_task: &CurrentTask, offset: usize, data: &mut dyn OutputBuffer, ) -> Result<usize, Errno>

Read from the file at an offset. If the file does not have persistent offsets (either directly, or because it is not seekable), offset will be 0 and can be ignored. Returns the number of bytes read.

fn write( &self, locked: &mut Locked<FileOpsCore>, file: &FileObject, current_task: &CurrentTask, offset: usize, data: &mut dyn InputBuffer, ) -> Result<usize, Errno>

Write to the file with an offset. If the file does not have persistent offsets (either directly, or because it is not seekable), offset will be 0 and can be ignored. Returns the number of bytes written.

fn seek( &self, locked: &mut Locked<FileOpsCore>, file: &FileObject, current_task: &CurrentTask, current_offset: off_t, target: SeekTarget, ) -> Result<off_t, Errno>

Adjust the current_offset if the file is seekable.

fn sync( &self, file: &FileObject, _current_task: &CurrentTask, ) -> Result<(), Errno>

Syncs cached state associated with the file descriptor to persistent storage.

The method blocks until the synchronization is complete.

Provided Methods

fn open( &self, _locked: &mut Locked<FileOpsCore>, _file: &FileObject, _current_task: &CurrentTask, ) -> Result<(), Errno>

Called when the FileObject is opened/created

fn close( self: Box<Self>, _locked: &mut Locked<FileOpsCore>, _file: &FileObjectState, _current_task: &CurrentTask, )

Called when the FileObject is destroyed.

fn flush( &self, _locked: &mut Locked<FileOpsCore>, _file: &FileObject, _current_task: &CurrentTask, )

Called every time close() is called on this file, even if the file is not ready to be released.

fn has_persistent_offsets(&self) -> bool

Returns whether the file has meaningful seek offsets. Returning false is only optimization and will makes FileObject never hold the offset lock when calling read and write.

fn writes_update_seek_offset(&self) -> bool

Returns true if write() operations on the file will update the seek offset.

fn data_sync( &self, file: &FileObject, current_task: &CurrentTask, ) -> Result<(), Errno>

Syncs cached data, and only enough metadata to retrieve said data, to persistent storage.

The method blocks until the synchronization is complete.

fn get_memory( &self, _locked: &mut Locked<FileOpsCore>, _file: &FileObject, _current_task: &CurrentTask, _length: Option<usize>, _prot: ProtectionFlags, ) -> Result<Arc<MemoryObject>, Errno>

Returns a VMO representing this file. At least the requested protection flags must be set on the VMO. Reading or writing the VMO must read or write the file. If this is not possible given the requested protection, an error must be returned. The length is a hint for the desired size of the VMO. The returned VMO may be larger or smaller than the requested length. This method is typically called by Self::mmap.

fn mmap( &self, locked: &mut Locked<FileOpsCore>, file: &FileObject, current_task: &CurrentTask, addr: DesiredAddress, memory_offset: u64, length: usize, prot_flags: ProtectionFlags, options: MappingOptions, filename: NamespaceNode, ) -> Result<UserAddress, Errno>

Responds to an mmap call. The default implementation calls Self::get_memory to get a VMO and then maps it with [crate::mm::MemoryManager::map]. Only implement this trait method if your file needs to control mapping, or record where a VMO gets mapped.

fn readdir( &self, _locked: &mut Locked<FileOpsCore>, _file: &FileObject, _current_task: &CurrentTask, _sink: &mut dyn DirentSink, ) -> Result<(), Errno>

Respond to a getdents or getdents64 calls.

The file.offset lock will be held while entering this method. The implementation must look at sink.offset() to read the current offset into the file.

fn wait_async( &self, _locked: &mut Locked<FileOpsCore>, _file: &FileObject, _current_task: &CurrentTask, _waiter: &Waiter, _events: FdEvents, _handler: EventHandler, ) -> Option<WaitCanceler>

Establish a one-shot, edge-triggered, asynchronous wait for the given FdEvents for the given file and task. Returns None if this file does not support blocking waits.

Active events are not considered. This is similar to the semantics of the ZX_WAIT_ASYNC_EDGE flag on zx_wait_async. To avoid missing events, the caller must call query_events after calling this.

If your file does not support blocking waits, leave this as the default implementation.

fn query_events( &self, _locked: &mut Locked<FileOpsCore>, _file: &FileObject, _current_task: &CurrentTask, ) -> Result<FdEvents, Errno>

The events currently active on this file.

If this function returns POLLIN or POLLOUT, then FileObject will add POLLRDNORM and POLLWRNORM, respective, which are equivalent in the Linux UAPI.

See https://linux.die.net/man/2/poll

fn ioctl( &self, locked: &mut Locked<Unlocked>, file: &FileObject, current_task: &CurrentTask, request: u32, arg: SyscallArg, ) -> Result<SyscallResult, Errno>

fn fcntl( &self, _file: &FileObject, _current_task: &CurrentTask, cmd: u32, _arg: u64, ) -> Result<SyscallResult, Errno>

fn to_handle( &self, file: &FileObject, current_task: &CurrentTask, ) -> Result<Option<NullableHandle>, Errno>

Return a handle that allows access to this file descritor through the zxio protocols.

If None is returned, the file will act as if it was a fd to /dev/null.

fn as_thread_group_key( &self, _file: &FileObject, ) -> Result<ThreadGroupKey, Errno>

Returns the associated pid_t.

Used by pidfd and /proc/<pid>. Unlikely to be used by other files.

fn readahead( &self, _file: &FileObject, _current_task: &CurrentTask, _offset: usize, _length: usize, ) -> Result<(), Errno>

fn extra_fdinfo( &self, _locked: &mut Locked<FileOpsCore>, _file: &FileHandle, _current_task: &CurrentTask, ) -> Option<FsString>

Extra information that is included in the /proc//fdfino/ entry.

Implementors

impl FileOps for BpfHandle

impl FileOps for DevNull

impl FileOps for DevRandom

impl FileOps for TtyFile

impl FileOps for RemoteCounter

impl FileOps for RemoteFileObject

impl FileOps for SyslogFile

impl FileOps for SyncFile

impl FileOps for PerfEventFile

impl FileOps for SignalFd

impl FileOps for PanickingFile

impl FileOps for EventFdFileObject

impl FileOps for InotifyFileObject

impl FileOps for IoUringFileObject

impl FileOps for MemoryDirectoryFile

impl FileOps for PidFdFileObject

impl FileOps for PipeFileObject

impl FileOps for ConstFile

impl FileOps for SimpleDirectory

impl FileOps for StubEmptyFile

impl FileOps for VecDirectory

impl FileOps for SocketFile

impl FileOps for EpollFileObject

impl FileOps for MemoryRegularFile

impl FileOps for MountNamespaceFile

impl FileOps for OPathOps

impl FileOps for ProcMountsFile

impl FileOps for ProxyFileOps

impl FileOps for UserFaultFile

impl FileOps for TimerFile

impl<Ops: BytesFileOps> FileOps for BytesFile<Ops>

impl<Source: SequenceFileSource> FileOps for DynamicFile<Source>

impl<T: FileOps + CloseFreeSafe, P: Deref<Target = T> + Send + Sync + 'static> FileOps for P