132 lines
3.1 KiB
Go
132 lines
3.1 KiB
Go
// Copyright 2018 The gVisor Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package fs
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import (
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"gvisor.dev/gvisor/pkg/abi/linux"
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)
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// FileFlags encodes file flags.
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//
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// +stateify savable
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type FileFlags struct {
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// Direct indicates that I/O should be done directly.
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Direct bool
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// NonBlocking indicates that I/O should not block.
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NonBlocking bool
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// DSync indicates that each write will flush data and metadata required to
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// read the file's contents.
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DSync bool
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// Sync indicates that each write will flush data and all file metadata.
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Sync bool
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// Append indicates this file is append only.
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Append bool
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// Read indicates this file is readable.
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Read bool
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// Write indicates this file is writeable.
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Write bool
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// Pread indicates this file is readable at an arbitrary offset.
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Pread bool
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// Pwrite indicates this file is writable at an arbitrary offset.
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Pwrite bool
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// Directory indicates that this file must be a directory.
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Directory bool
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// Async indicates that this file sends signals on IO events.
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Async bool
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// LargeFile indicates that this file should be opened even if it has
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// size greater than linux's off_t. When running in 64-bit mode,
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// Linux sets this flag for all files. Since gVisor is only compatible
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// with 64-bit Linux, it also sets this flag for all files.
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LargeFile bool
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// NonSeekable indicates that file.offset isn't used.
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NonSeekable bool
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}
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// SettableFileFlags is a subset of FileFlags above that can be changed
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// via fcntl(2) using the F_SETFL command.
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type SettableFileFlags struct {
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// Direct indicates that I/O should be done directly.
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Direct bool
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// NonBlocking indicates that I/O should not block.
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NonBlocking bool
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// Append indicates this file is append only.
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Append bool
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// Async indicates that this file sends signals on IO events.
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Async bool
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}
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// Settable returns the subset of f that are settable.
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func (f FileFlags) Settable() SettableFileFlags {
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return SettableFileFlags{
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Direct: f.Direct,
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NonBlocking: f.NonBlocking,
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Append: f.Append,
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Async: f.Async,
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}
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}
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// ToLinux converts a FileFlags object to a Linux representation.
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func (f FileFlags) ToLinux() (mask uint) {
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if f.Direct {
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mask |= linux.O_DIRECT
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}
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if f.NonBlocking {
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mask |= linux.O_NONBLOCK
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}
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if f.DSync {
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mask |= linux.O_DSYNC
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}
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if f.Sync {
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mask |= linux.O_SYNC
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}
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if f.Append {
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mask |= linux.O_APPEND
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}
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if f.Directory {
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mask |= linux.O_DIRECTORY
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}
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if f.Async {
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mask |= linux.O_ASYNC
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}
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if f.LargeFile {
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mask |= linux.O_LARGEFILE
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}
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switch {
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case f.Read && f.Write:
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mask |= linux.O_RDWR
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case f.Write:
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mask |= linux.O_WRONLY
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case f.Read:
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mask |= linux.O_RDONLY
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}
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return
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}
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