mirror of
https://github.com/token2/snapd.git
synced 2026-03-13 11:15:47 -07:00
b4f263bba8
Some invocations to external programs used exec.CombinedOutput, that combines stdout and strerr into a single byte array. This can be an issue if this output is parsed, as many programs print debug output or warnings to stderr and that data is unexpected by the parsers. This patch changes to using osutil.RunSplitOutput or osutil.RunCmd (that return separately stdout and stderr) when we need to parse stdout, and also in some other cases when printing separately both streams could be helpful. Fixes LP #1885597.
379 lines
12 KiB
Go
379 lines
12 KiB
Go
// -*- Mode: Go; indent-tabs-mode: t -*-
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/*
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* Copyright (C) 2017-2020 Canonical Ltd
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 3 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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package userd
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import (
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"fmt"
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"os/exec"
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"path/filepath"
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"strings"
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"time"
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"github.com/godbus/dbus"
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"github.com/snapcore/snapd/dirs"
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"github.com/snapcore/snapd/i18n"
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"github.com/snapcore/snapd/osutil"
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"github.com/snapcore/snapd/snap"
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"github.com/snapcore/snapd/usersession/userd/ui"
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)
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// Timeout when the confirmation dialog for an xdg-setging
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// automatically closes. Keep in sync with the core snaps
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// xdg-settings wrapper which also sets this value to 300.
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var defaultConfirmDialogTimeout = 300 * time.Second
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const settingsIntrospectionXML = `
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<interface name="org.freedesktop.DBus.Peer">
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<method name='Ping'>
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</method>
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<method name='GetMachineId'>
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<arg type='s' name='machine_uuid' direction='out'/>
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</method>
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</interface>
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<interface name='io.snapcraft.Settings'>
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<method name='Check'>
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<arg type='s' name='setting' direction='in'/>
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<arg type='s' name='check' direction='in'/>
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<arg type='s' name='result' direction='out'/>
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</method>
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<method name='CheckSub'>
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<arg type='s' name='setting' direction='in'/>
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<arg type='s' name='subproperty' direction='in'/>
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<arg type='s' name='check' direction='in'/>
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<arg type='s' name='result' direction='out'/>
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</method>
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<method name='Get'>
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<arg type='s' name='setting' direction='in'/>
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<arg type='s' name='result' direction='out'/>
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</method>
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<method name='GetSub'>
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<arg type='s' name='setting' direction='in'/>
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<arg type='s' name='subproperty' direction='in'/>
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<arg type='s' name='result' direction='out'/>
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</method>
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<method name='Set'>
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<arg type='s' name='setting' direction='in'/>
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<arg type='s' name='value' direction='in'/>
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</method>
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<method name='SetSub'>
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<arg type='s' name='setting' direction='in'/>
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<arg type='s' name='subproperty' direction='in'/>
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<arg type='s' name='value' direction='in'/>
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</method>
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</interface>`
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var validSettings = []string{
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"default-web-browser",
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"default-url-scheme-handler",
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}
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func allowedSetting(setting string) bool {
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if !strings.HasSuffix(setting, ".desktop") {
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return false
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}
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base := strings.TrimSuffix(setting, ".desktop")
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return snap.ValidAppName(base)
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}
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// settingSpec specifies a setting with an optional subproperty
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type settingSpec struct {
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setting string
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subproperty string
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}
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func (s *settingSpec) String() string {
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if s.subproperty != "" {
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return fmt.Sprintf("%q subproperty %q", s.setting, s.subproperty)
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} else {
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return fmt.Sprintf("%q", s.setting)
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}
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}
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func (s *settingSpec) validate() *dbus.Error {
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for _, valid := range validSettings {
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if s.setting == valid {
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return nil
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}
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}
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return dbus.MakeFailedError(fmt.Errorf("invalid setting %q", s.setting))
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}
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// Settings implements the 'io.snapcraft.Settings' DBus interface.
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type Settings struct {
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conn *dbus.Conn
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}
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// Interface returns the name of the interface this object implements
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func (s *Settings) Interface() string {
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return "io.snapcraft.Settings"
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}
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// ObjectPath returns the path that the object is exported as
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func (s *Settings) ObjectPath() dbus.ObjectPath {
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return "/io/snapcraft/Settings"
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}
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// IntrospectionData gives the XML formatted introspection description
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// of the DBus service.
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func (s *Settings) IntrospectionData() string {
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return settingsIntrospectionXML
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}
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// some notes:
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// - we only set/get desktop files
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// - all desktop files of snaps are prefixed with: ${snap}_
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// - on get/check/set we need to add/strip this prefix
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func safeSnapFromSender(s *Settings, sender dbus.Sender) (string, *dbus.Error) {
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// avoid information leak: see https://github.com/snapcore/snapd/pull/4073#discussion_r146682758
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snap, err := snapFromSender(s.conn, sender)
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if err != nil {
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return "", dbus.MakeFailedError(err)
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}
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return snap, nil
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}
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func desktopFileFromValueForSetting(s *Settings, command string, setspec *settingSpec, dotDesktopValue string, sender dbus.Sender) (string, *dbus.Error) {
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snap, err := safeSnapFromSender(s, sender)
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if err != nil {
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return "", err
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}
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if err := setspec.validate(); err != nil {
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return "", err
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}
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if !allowedSetting(dotDesktopValue) {
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return "", dbus.MakeFailedError(fmt.Errorf("cannot %s %s setting to invalid value %q", command, setspec, dotDesktopValue))
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}
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// FIXME: this works only for desktop files
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desktopFile := fmt.Sprintf("%s_%s", snap, dotDesktopValue)
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return desktopFile, nil
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}
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func desktopFileFromOutput(s *Settings, output string, sender dbus.Sender) (string, *dbus.Error) {
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snap, err := safeSnapFromSender(s, sender)
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if err != nil {
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return "", err
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}
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if !strings.HasPrefix(output, snap+"_") {
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return "NOT-THIS-SNAP.desktop", nil
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}
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desktopFile := strings.SplitN(output, "_", 2)[1]
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return strings.TrimSpace(desktopFile), nil
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}
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func setDialog(s *Settings, setspec *settingSpec, desktopFile string, sender dbus.Sender) *dbus.Error {
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df := filepath.Join(dirs.SnapDesktopFilesDir, desktopFile)
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if !osutil.FileExists(df) {
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return dbus.MakeFailedError(fmt.Errorf("cannot find desktop file %q", df))
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}
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// FIXME: we need to know the parent PID or our dialog may pop under
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// the existing windows. We might get it with the help of
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// the xdg-settings tool inside the core snap. It would have
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// to get the PID of the process asking for the settings
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// then xdg-settings can sent this to us and we can intospect
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// the X windows for _NET_WM_PID and use the windowID to
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// attach to zenity - not sure how this translate to the
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// wayland world though :/
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dialog, uiErr := ui.New()
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if uiErr != nil {
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return dbus.MakeFailedError(fmt.Errorf("cannot ask for settings change: %v", uiErr))
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}
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snap, err := safeSnapFromSender(s, sender)
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if err != nil {
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return err
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}
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answeredYes := dialog.YesNo(
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i18n.G("Allow settings change?"),
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fmt.Sprintf(i18n.G("Allow snap %q to change %s to %q ?"), snap, setspec, desktopFile),
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&ui.DialogOptions{
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Timeout: defaultConfirmDialogTimeout,
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Footer: i18n.G("This dialog will close automatically after 5 minutes of inactivity."),
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},
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)
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if !answeredYes {
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return dbus.MakeFailedError(fmt.Errorf("cannot change configuration: user declined change"))
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}
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return nil
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}
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func checkOutput(cmd *exec.Cmd, command string, setspec *settingSpec) (string, *dbus.Error) {
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output, stderr, err := osutil.RunCmd(cmd)
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if err != nil {
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return "", dbus.MakeFailedError(fmt.Errorf("cannot %s %s setting: %s", command, setspec, osutil.OutputErrCombine(output, stderr, err)))
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}
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return string(output), nil
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}
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// Check implements the 'Check' method of the 'io.snapcraft.Settings'
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// DBus interface.
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//
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// Example usage: dbus-send --session --dest=io.snapcraft.Settings --type=method_call --print-reply /io/snapcraft/Settings io.snapcraft.Settings.Check string:'default-web-browser' string:'firefox.desktop'
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func (s *Settings) Check(setting string, check string, sender dbus.Sender) (string, *dbus.Error) {
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if err := checkOnClassic(); err != nil {
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return "", err
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}
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settingMain := &settingSpec{setting: setting}
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desktopFile, err := desktopFileFromValueForSetting(s, "check", settingMain, check, sender)
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if err != nil {
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return "", err
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}
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cmd := exec.Command("xdg-settings", "check", setting, desktopFile)
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output, err := checkOutput(cmd, "check", settingMain)
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if err != nil {
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return "", err
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}
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return strings.TrimSpace(output), nil
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}
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// CheckSub implements the 'CheckSub' method of the 'io.snapcraft.Settings'
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// DBus interface.
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//
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// Example usage: dbus-send --session --dest=io.snapcraft.Settings --type=method_call --print-reply /io/snapcraft/Settings io.snapcraft.Settings.CheckSub string:'default-url-scheme-handler' string:'irc' string:'ircclient.desktop'
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func (s *Settings) CheckSub(setting string, subproperty string, check string, sender dbus.Sender) (string, *dbus.Error) {
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if err := checkOnClassic(); err != nil {
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return "", err
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}
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settingSub := &settingSpec{setting: setting, subproperty: subproperty}
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desktopFile, err := desktopFileFromValueForSetting(s, "check", settingSub, check, sender)
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if err != nil {
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return "", err
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}
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cmd := exec.Command("xdg-settings", "check", setting, subproperty, desktopFile)
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output, err := checkOutput(cmd, "check", settingSub)
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if err != nil {
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return "", err
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}
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return strings.TrimSpace(output), nil
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}
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// Get implements the 'Get' method of the 'io.snapcraft.Settings'
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// DBus interface.
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//
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// Example usage: dbus-send --session --dest=io.snapcraft.Settings --type=method_call --print-reply /io/snapcraft/Settings io.snapcraft.Settings.Get string:'default-web-browser'
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func (s *Settings) Get(setting string, sender dbus.Sender) (string, *dbus.Error) {
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if err := checkOnClassic(); err != nil {
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return "", err
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}
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settingMain := &settingSpec{setting: setting}
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if err := settingMain.validate(); err != nil {
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return "", err
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}
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cmd := exec.Command("xdg-settings", "get", setting)
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output, err := checkOutput(cmd, "get", settingMain)
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if err != nil {
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return "", err
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}
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return desktopFileFromOutput(s, output, sender)
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}
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// GetSub implements the 'GetSub' method of the 'io.snapcraft.Settings'
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// DBus interface.
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//
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// Example usage: dbus-send --session --dest=io.snapcraft.Settings --type=method_call --print-reply /io/snapcraft/Settings io.snapcraft.Settings.GetSub string:'default-url-scheme-handler' string:'irc'
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func (s *Settings) GetSub(setting string, subproperty string, sender dbus.Sender) (string, *dbus.Error) {
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if err := checkOnClassic(); err != nil {
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return "", err
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}
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settingSub := &settingSpec{setting: setting, subproperty: subproperty}
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if err := settingSub.validate(); err != nil {
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return "", err
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}
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cmd := exec.Command("xdg-settings", "get", setting, subproperty)
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output, err := checkOutput(cmd, "get", settingSub)
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if err != nil {
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return "", err
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}
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return desktopFileFromOutput(s, output, sender)
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}
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// Set implements the 'Set' method of the 'io.snapcraft.Settings'
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// DBus interface.
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//
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// Example usage: dbus-send --session --dest=io.snapcraft.Settings --type=method_call --print-reply /io/snapcraft/Settings io.snapcraft.Settings.Set string:'default-web-browser' string:'chromium-browser.desktop'
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func (s *Settings) Set(setting string, new string, sender dbus.Sender) *dbus.Error {
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if err := checkOnClassic(); err != nil {
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return err
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}
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settingMain := &settingSpec{setting: setting}
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desktopFile, err := desktopFileFromValueForSetting(s, "set", settingMain, new, sender)
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if err != nil {
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return err
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}
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if err := setDialog(s, settingMain, desktopFile, sender); err != nil {
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return err
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}
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cmd := exec.Command("xdg-settings", "set", setting, desktopFile)
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if _, err := checkOutput(cmd, "set", settingMain); err != nil {
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return err
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}
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return nil
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}
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// SetSub implements the 'SetSub' method of the 'io.snapcraft.Settings'
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// DBus interface.
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//
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// Example usage: dbus-send --session --dest=io.snapcraft.Settings --type=method_call --print-reply /io/snapcraft/Settings io.snapcraft.Settings.SetSub string:'default-url-scheme-handler' string:'irc' string:'ircclient.desktop'
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func (s *Settings) SetSub(setting string, subproperty string, new string, sender dbus.Sender) *dbus.Error {
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if err := checkOnClassic(); err != nil {
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return err
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}
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settingSub := &settingSpec{setting: setting, subproperty: subproperty}
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desktopFile, err := desktopFileFromValueForSetting(s, "set", settingSub, new, sender)
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if err != nil {
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return err
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}
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if err := setDialog(s, settingSub, desktopFile, sender); err != nil {
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return err
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}
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cmd := exec.Command("xdg-settings", "set", setting, subproperty, desktopFile)
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if _, err := checkOutput(cmd, "set", settingSub); err != nil {
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return err
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}
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return nil
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}
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