107 lines
4.4 KiB
Go
107 lines
4.4 KiB
Go
// Copyright 2018 Google Inc.
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
package fs
|
|
|
|
import (
|
|
"gvisor.googlesource.com/gvisor/pkg/sentry/arch"
|
|
"gvisor.googlesource.com/gvisor/pkg/sentry/context"
|
|
"gvisor.googlesource.com/gvisor/pkg/sentry/memmap"
|
|
"gvisor.googlesource.com/gvisor/pkg/sentry/usermem"
|
|
"gvisor.googlesource.com/gvisor/pkg/waiter"
|
|
)
|
|
|
|
// FileOperations are operations on a File that diverge per file system.
|
|
//
|
|
// Operations that take a *File may use only the following interfaces:
|
|
//
|
|
// - File.UniqueID: Operations may only read this value.
|
|
// - File.Dirent: Operations must not take or drop a reference.
|
|
// - File.Offset(): This value is guaranteed to not change for the
|
|
// duration of the operation.
|
|
// - File.Flags(): This value may change during the operation.
|
|
type FileOperations interface {
|
|
// Release release resources held by FileOperations.
|
|
Release()
|
|
|
|
// Waitable defines how this File can be waited on for read and
|
|
// write readiness.
|
|
waiter.Waitable
|
|
|
|
// Seek seeks to offset based on SeekWhence. Returns the new
|
|
// offset or no change in the offset and an error.
|
|
Seek(ctx context.Context, file *File, whence SeekWhence, offset int64) (int64, error)
|
|
|
|
// Readdir reads the directory entries of file and serializes them
|
|
// using serializer.
|
|
//
|
|
// Returns the new directory offset or no change in the offset and
|
|
// an error. The offset returned must not be less than file.Offset().
|
|
//
|
|
// Serialization of directory entries must not happen asynchronously.
|
|
Readdir(ctx context.Context, file *File, serializer DentrySerializer) (int64, error)
|
|
|
|
// Read reads from file into dst at offset and returns the number
|
|
// of bytes read which must be greater than or equal to 0. File
|
|
// systems that do not support reading at an offset, (i.e. pipefs,
|
|
// sockfs) may ignore the offset. These file systems are expected
|
|
// to construct Files with !FileFlags.Pread.
|
|
//
|
|
// Read may return a nil error and only partially fill dst (at or
|
|
// before EOF). If the file represents a symlink, Read reads the target
|
|
// value of the symlink.
|
|
//
|
|
// Read does not check permissions nor flags.
|
|
//
|
|
// Read must not be called if !FileFlags.Read.
|
|
Read(ctx context.Context, file *File, dst usermem.IOSequence, offset int64) (int64, error)
|
|
|
|
// Write writes src to file at offset and returns the number of bytes
|
|
// written which must be greater than or equal to 0. Like Read, file
|
|
// systems that do not support writing at an offset (i.e. pipefs, sockfs)
|
|
// may ignore the offset. These file systems are expected to construct
|
|
// Files with !FileFlags.Pwrite.
|
|
//
|
|
// If only part of src could be written, Write must return an error
|
|
// indicating why (e.g. syserror.ErrWouldBlock).
|
|
//
|
|
// Write does not check permissions nor flags.
|
|
//
|
|
// Write must not be called if !FileFlags.Write.
|
|
Write(ctx context.Context, file *File, src usermem.IOSequence, offset int64) (int64, error)
|
|
|
|
// Fsync writes buffered modifications of file and/or flushes in-flight
|
|
// operations to backing storage based on syncType. The range to sync is
|
|
// [start, end]. The end is inclusive so that the last byte of a maximally
|
|
// sized file can be synced.
|
|
Fsync(ctx context.Context, file *File, start, end int64, syncType SyncType) error
|
|
|
|
// Flush this file's buffers/state (on close(2)).
|
|
Flush(ctx context.Context, file *File) error
|
|
|
|
// ConfigureMMap mutates opts to implement mmap(2) for the file. Most
|
|
// implementations can either embed fsutil.NoMMap (if they don't support
|
|
// memory mapping) or call fsutil.GenericConfigureMMap with the appropriate
|
|
// memmap.Mappable.
|
|
ConfigureMMap(ctx context.Context, file *File, opts *memmap.MMapOpts) error
|
|
|
|
// Ioctl implements the ioctl(2) linux syscall.
|
|
//
|
|
// io provides access to the virtual memory space to which pointers in args
|
|
// refer.
|
|
//
|
|
// Preconditions: The AddressSpace (if any) that io refers to is activated.
|
|
Ioctl(ctx context.Context, io usermem.IO, args arch.SyscallArguments) (uintptr, error)
|
|
}
|