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// Copyright (C) 2016-2017 Luke Shumaker <lukeshu@sbcglobal.net>
//
// 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 sd_login
import (
"strconv"
"strings"
"golang.org/x/sys/unix"
)
// A SeatName represents a set of hardware devices for a workspace; i.e. a
// screen and keyboard.
//
// Multiple sessions may be associated with a seat (if
// seat.CanMultiSession()), but only one session may be active on a
// seat at a time.
type SeatName string
// A SessionNameWithUID is a just a SessionName with a User ID already
// associated with it, so that a separate lookup for GetUser isn't
// necessary.
type SessionNameWithUID struct {
SessionName
User UserID
}
func (sess SessionNameWithUID) GetUser() (UserID, error) {
return sess.User, nil
}
func (seat SeatName) isValid() bool {
return valid_filename(string(seat))
}
// GetSeats returns a list of all currently available local seats.
func GetSeats() ([]SeatName, error) {
strs, err := get_files_in_directory("/run/systemd/seats/")
if err != nil {
return nil, err
}
seats := make([]SeatName, len(strs))
for i := range strs {
seats[i] = SeatName(strs[i])
}
return seats, nil
}
// GetActive returns which session is currently active on this seat,
// or nil if there is no currently active session.
func (seat SeatName) GetActive() (sess SessionNameWithUID, err error) {
if !seat.isValid() {
err = unix.EINVAL
return
}
env, err := parse_env_file("/run/systemd/seats/" + string(seat))
if err != nil {
return
}
strName, ok := env["ACTIVE"]
if !ok {
err = unix.ENXIO
return
}
strUid, ok := env["ACTIVE_UID"]
if !ok {
err = unix.ENXIO
return
}
intUid, err := strconv.Atoi(strUid)
if err != nil {
return
}
sess.SessionName = SessionName(strName)
sess.User = UserID(intUid)
return
}
// GetSessions returns a list of all sessions associated with the
// seat, whether they are active or not.
func (seat SeatName) GetSessions() ([]SessionNameWithUID, error) {
if !seat.isValid() {
return nil, unix.EINVAL
}
env, err := parse_env_file("/run/systemd/seats/" + string(seat))
if err != nil {
return nil, err
}
strSessions, ok := env["SESSIONS"]
if !ok {
return nil, unix.ENXIO
}
strUids, ok := env["UIDS"]
if !ok {
return nil, unix.ENXIO
}
arySessions := strings.Fields(strSessions)
aryUids := strings.Fields(strUids)
if len(arySessions) != len(aryUids) {
return nil, unix.ENXIO
}
ret := make([]SessionNameWithUID, len(arySessions))
for i := 0; i < len(arySessions); i++ {
uid, err := strconv.Atoi(aryUids[i])
if err != nil {
return nil, err
}
ret[i].SessionName = SessionName(arySessions[i])
ret[i].User = UserID(uid)
}
return ret, nil
}
func (seat SeatName) can(cap string) (bool, error) {
if !seat.isValid() {
return false, unix.EINVAL
}
env, err := parse_env_file("/run/systemd/seats/" + string(seat))
if err != nil {
return false, err
}
return parse_boolean(env["CAN_"+cap])
}
// CanMultiSession returns whether this seat is capable of
// multi-session, i.e. login sessions in parallel (with only one being
// active at a time).
func (seat SeatName) CanMultiSession() (bool, error) {
return seat.can("MULTI_SESSION")
}
// CanTTY returns whether this seat provides TTY functionality,
// i.e. is useful as a text console.
func (seat SeatName) CanTTY() (bool, error) {
return seat.can("TTY")
}
// CanGraphical returns whether this seat provides graphics
// functionality, i.e. is useful as a graphics display.
func (seat SeatName) CanGraphical() (bool, error) {
return seat.can("GRAPHICAL")
}
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