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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 tty
import (
"gvisor.googlesource.com/gvisor/pkg/abi/linux"
"gvisor.googlesource.com/gvisor/pkg/sentry/arch"
"gvisor.googlesource.com/gvisor/pkg/sentry/context"
"gvisor.googlesource.com/gvisor/pkg/sentry/fs"
"gvisor.googlesource.com/gvisor/pkg/sentry/fs/fsutil"
"gvisor.googlesource.com/gvisor/pkg/sentry/usermem"
"gvisor.googlesource.com/gvisor/pkg/syserror"
"gvisor.googlesource.com/gvisor/pkg/waiter"
)
// masterInodeOperations are the fs.InodeOperations for the master end of the
// Terminal (ptmx file).
//
// +stateify savable
type masterInodeOperations struct {
inodeOperations
// d is the containing dir.
d *dirInodeOperations
}
var _ fs.InodeOperations = (*masterInodeOperations)(nil)
// newMasterInode creates an Inode for the master end of a terminal.
func newMasterInode(ctx context.Context, d *dirInodeOperations, owner fs.FileOwner, p fs.FilePermissions) *fs.Inode {
iops := &masterInodeOperations{
inodeOperations: inodeOperations{
uattr: fs.WithCurrentTime(ctx, fs.UnstableAttr{
Owner: owner,
Perms: p,
Links: 1,
// Size and Blocks are always 0.
}),
},
d: d,
}
return fs.NewInode(iops, d.msrc, fs.StableAttr{
DeviceID: ptsDevice.DeviceID(),
// N.B. Linux always uses inode id 2 for ptmx. See
// fs/devpts/inode.c:mknod_ptmx.
//
// TODO: Since ptsDevice must be shared between
// different mounts, we must not assign fixed numbers.
InodeID: ptsDevice.NextIno(),
Type: fs.CharacterDevice,
// See fs/devpts/inode.c:devpts_fill_super.
BlockSize: 1024,
// The PTY master effectively has two different major/minor
// device numbers.
//
// This one is returned by stat for both opened and unopened
// instances of this inode.
//
// When the inode is opened (GetFile), a new device number is
// allocated based on major UNIX98_PTY_MASTER_MAJOR and the tty
// index as minor number. However, this device number is only
// accessible via ioctl(TIOCGDEV) and /proc/TID/stat.
DeviceFileMajor: linux.TTYAUX_MAJOR,
DeviceFileMinor: linux.PTMX_MINOR,
})
}
// Release implements fs.InodeOperations.Release.
func (mi *masterInodeOperations) Release(ctx context.Context) {
}
// GetFile implements fs.InodeOperations.GetFile.
//
// It allocates a new terminal.
func (mi *masterInodeOperations) GetFile(ctx context.Context, d *fs.Dirent, flags fs.FileFlags) (*fs.File, error) {
t, err := mi.d.allocateTerminal(ctx)
if err != nil {
return nil, err
}
return fs.NewFile(ctx, d, flags, &masterFileOperations{
d: mi.d,
t: t,
}), nil
}
// masterFileOperations are the fs.FileOperations for the master end of a terminal.
//
// +stateify savable
type masterFileOperations struct {
fsutil.PipeSeek `state:"nosave"`
fsutil.NotDirReaddir `state:"nosave"`
fsutil.NoFsync `state:"nosave"`
fsutil.NoopFlush `state:"nosave"`
fsutil.NoMMap `state:"nosave"`
// d is the containing dir.
d *dirInodeOperations
// t is the connected Terminal.
t *Terminal
}
var _ fs.FileOperations = (*masterFileOperations)(nil)
// Release implements fs.FileOperations.Release.
func (mf *masterFileOperations) Release() {
mf.d.masterClose(mf.t)
mf.t.DecRef()
}
// EventRegister implements waiter.Waitable.EventRegister.
func (mf *masterFileOperations) EventRegister(e *waiter.Entry, mask waiter.EventMask) {
mf.t.ld.inQueue.EventRegister(e, mask)
mf.t.ld.outQueue.EventRegister(e, mask)
}
// EventUnregister implements waiter.Waitable.EventUnregister.
func (mf *masterFileOperations) EventUnregister(e *waiter.Entry) {
mf.t.ld.inQueue.EventUnregister(e)
mf.t.ld.outQueue.EventUnregister(e)
}
// Readiness implements waiter.Waitable.Readiness.
func (mf *masterFileOperations) Readiness(mask waiter.EventMask) waiter.EventMask {
return mf.t.ld.masterReadiness()
}
// Read implements fs.FileOperations.Read.
func (mf *masterFileOperations) Read(ctx context.Context, _ *fs.File, dst usermem.IOSequence, _ int64) (int64, error) {
return mf.t.ld.outputQueueRead(ctx, dst)
}
// Write implements fs.FileOperations.Write.
func (mf *masterFileOperations) Write(ctx context.Context, _ *fs.File, src usermem.IOSequence, _ int64) (int64, error) {
return mf.t.ld.inputQueueWrite(ctx, src)
}
// Ioctl implements fs.FileOperations.Ioctl.
func (mf *masterFileOperations) Ioctl(ctx context.Context, io usermem.IO, args arch.SyscallArguments) (uintptr, error) {
switch args[1].Uint() {
case linux.FIONREAD: // linux.FIONREAD == linux.TIOCINQ
// Get the number of bytes in the output queue read buffer.
return 0, mf.t.ld.outputQueueReadSize(ctx, io, args)
case linux.TCGETS:
// N.B. TCGETS on the master actually returns the configuration
// of the slave end.
return mf.t.ld.getTermios(ctx, io, args)
case linux.TCSETS:
// N.B. TCSETS on the master actually affects the configuration
// of the slave end.
return mf.t.ld.setTermios(ctx, io, args)
case linux.TCSETSW:
// TODO: This should drain the output queue first.
return mf.t.ld.setTermios(ctx, io, args)
case linux.TIOCGPTN:
_, err := usermem.CopyObjectOut(ctx, io, args[2].Pointer(), uint32(mf.t.n), usermem.IOOpts{
AddressSpaceActive: true,
})
return 0, err
case linux.TIOCSPTLCK:
// TODO: Implement pty locking. For now just pretend we do.
return 0, nil
default:
return 0, syserror.ENOTTY
}
}
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