1 files changed, 109 insertions, 7 deletions

diff --git a/sd_login/type_seat.go b/sd_login/type_seat.go
index fd86663..a62effc 100644
--- a/sd_login/type_seat.go
+++ b/sd_login/type_seat.go
@@ -1,4 +1,4 @@
-// Copyright (C) 2016 Luke Shumaker <lukeshu@sbcglobal.net>
+// 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.
@@ -14,9 +14,25 @@
 
 package sd_login
 
+import (
+	"strconv"
+	"strings"
+
+	"golang.org/x/sys/unix"
+)
+
+// A Seat represents a set of hardware devices for a workspace; i.e. a
+// screen and keyboard.
+//
+// Multiple sessions may be associated with a seat, but only one
+// session may be active on a seat at a time.
 type Seat string
 
-// GetSeats returns a list of all currently avialable local seats.
+func (seat Seat) isValid() bool {
+	return valid_filename(string(seat))
+}
+
+// GetSeats returns a list of all currently available local seats.
 func GetSeats() ([]Seat, error) {
 	strs, err := get_files_in_directory("/run/systemd/seats/")
 	if err != nil {
@@ -29,9 +45,95 @@ func GetSeats() ([]Seat, error) {
 	return seats, nil
 }
 
-func (seat Seat) GetActive() (Session, User, error)
-func (seat Seat) GetSessions() ([]Session, []User, error)
+// GetActive returns which session is currently active on this seat,
+// or nil if there is no currently active session.
+func (seat Seat) GetActive() (sess AnnotatedSession, 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.Session = Session(strName)
+	sess.User = User(intUid)
+
+	return
+}
+
+// GetSessions returns a list of all sessions associated with the
+// seat, whether they are active or not.
+func (seat Seat) GetSessions() ([]AnnotatedSession, 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([]AnnotatedSession, len(arySessions))
+	for i := 0; i < len(arySessions); i++ {
+		uid, err := strconv.Atoi(aryUids[i])
+		if err != nil {
+			return nil, err
+		}
+		ret[i].Session = Session(arySessions[i])
+		ret[i].User = User(uid)
+	}
+
+	return ret, nil
+}
+
+func (seat Seat) 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])
+}
 
-func (seat Seat) CanMultiSession() bool
-func (seat Seat) CanTTY() bool
-func (seat Seat) CanGraphical() bool
+func (seat Seat) CanMultiSession() (bool, error) {
+	return seat.can("MULTI_SESSION")
+}
+
+func (seat Seat) CanTTY() (bool, error) {
+	return seat.can("TTY")
+}
+
+func (seat Seat) CanGraphical() (bool, error) {
+	return seat.can("GRAPHICAL")
+}