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// 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 linux
import (
"syscall"
"gvisor.googlesource.com/gvisor/pkg/sentry/fs"
"gvisor.googlesource.com/gvisor/pkg/sentry/kernel"
)
// flagsToPermissions returns a Permissions object from Linux flags.
// This includes truncate permission if O_TRUNC is set in the mask.
func flagsToPermissions(mask uint) (p fs.PermMask) {
switch mask & syscall.O_ACCMODE {
case syscall.O_WRONLY:
p.Write = true
case syscall.O_RDWR:
p.Write = true
p.Read = true
case syscall.O_RDONLY:
p.Read = true
}
return
}
// fdFlagsToLinux converts a kernel.FDFlags object to a Linux representation.
func fdFlagsToLinux(flags kernel.FDFlags) (mask uint) {
if flags.CloseOnExec {
mask |= syscall.FD_CLOEXEC
}
return
}
// flagsToLinux converts a FileFlags object to a Linux representation.
func flagsToLinux(flags fs.FileFlags) (mask uint) {
if flags.Direct {
mask |= syscall.O_DIRECT
}
if flags.NonBlocking {
mask |= syscall.O_NONBLOCK
}
if flags.Sync {
mask |= syscall.O_SYNC
}
if flags.Append {
mask |= syscall.O_APPEND
}
if flags.Directory {
mask |= syscall.O_DIRECTORY
}
switch {
case flags.Read && flags.Write:
mask |= syscall.O_RDWR
case flags.Write:
mask |= syscall.O_WRONLY
case flags.Read:
mask |= syscall.O_RDONLY
}
return
}
// linuxToFlags converts linux file flags to a FileFlags object.
func linuxToFlags(mask uint) (flags fs.FileFlags) {
return fs.FileFlags{
Direct: mask&syscall.O_DIRECT != 0,
Sync: mask&syscall.O_SYNC != 0,
NonBlocking: mask&syscall.O_NONBLOCK != 0,
Read: (mask & syscall.O_ACCMODE) != syscall.O_WRONLY,
Write: (mask & syscall.O_ACCMODE) != syscall.O_RDONLY,
Append: mask&syscall.O_APPEND != 0,
Directory: mask&syscall.O_DIRECTORY != 0,
}
}
// linuxToSettableFlags converts linux file flags to a SettableFileFlags object.
func linuxToSettableFlags(mask uint) fs.SettableFileFlags {
return fs.SettableFileFlags{
Direct: mask&syscall.O_DIRECT != 0,
NonBlocking: mask&syscall.O_NONBLOCK != 0,
Append: mask&syscall.O_APPEND != 0,
}
}
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