Files
Nicolas Lacasse 72193f12c9 Implement /dev/tty for sentry-internal ttys.
The /dev/tty acts as a replica for the current thread group's controlling
terminal.

In a follow-up, I will make /dev/tty work for donated host ttys.

Updates #10925

PiperOrigin-RevId: 681629892
2024-10-02 16:23:54 -07:00

61 lines
1.8 KiB
Go

// Copyright 2020 The gVisor Authors.
//
// 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 ttydev implements a vfs.Device for /dev/tty.
package ttydev
import (
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/errors/linuxerr"
"gvisor.dev/gvisor/pkg/sentry/kernel"
"gvisor.dev/gvisor/pkg/sentry/vfs"
)
const (
// See drivers/tty/tty_io.c:tty_init().
ttyDevMinor = 0
consoleDevMinor = 1
)
// ttyDevice implements vfs.Device for /dev/tty.
//
// +stateify savable
type ttyDevice struct{}
// Open implements vfs.Device.Open.
func (ttyDevice) Open(ctx context.Context, mnt *vfs.Mount, vfsd *vfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) {
t := kernel.TaskFromContext(ctx)
if t == nil {
return nil, linuxerr.ENXIO
}
tty := t.ThreadGroup().TTY()
if tty == nil {
return nil, linuxerr.ENXIO
}
// Opening /dev/tty does not set the controlling terminal. See Linux
// tty_open().
opts.Flags |= linux.O_NOCTTY
return tty.Open(ctx, mnt, vfsd, opts)
}
// Register registers all devices implemented by this package in vfsObj.
func Register(vfsObj *vfs.VirtualFilesystem) error {
return vfsObj.RegisterDevice(vfs.CharDevice, linux.TTYAUX_MAJOR, ttyDevMinor, ttyDevice{}, &vfs.RegisterDeviceOptions{
GroupName: "tty",
Pathname: "tty",
FilePerms: 0666,
})
}