github.com/meulengracht/snapd@v0.0.0-20210719210640-8bde69bcc84e/cmd/snap/cmd_routine_portal_info.go (about)

     1  // -*- Mode: Go; indent-tabs-mode: t -*-
     2  
     3  /*
     4   * Copyright (C) 2019 Canonical Ltd
     5   *
     6   * This program is free software: you can redistribute it and/or modify
     7   * it under the terms of the GNU General Public License version 3 as
     8   * published by the Free Software Foundation.
     9   *
    10   * This program is distributed in the hope that it will be useful,
    11   * but WITHOUT ANY WARRANTY; without even the implied warranty of
    12   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    13   * GNU General Public License for more details.
    14   *
    15   * You should have received a copy of the GNU General Public License
    16   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
    17   *
    18   */
    19  
    20  package main
    21  
    22  import (
    23  	"fmt"
    24  	"path/filepath"
    25  	"text/template"
    26  
    27  	"github.com/jessevdk/go-flags"
    28  
    29  	"github.com/snapcore/snapd/client"
    30  	"github.com/snapcore/snapd/i18n"
    31  	"github.com/snapcore/snapd/sandbox/apparmor"
    32  	"github.com/snapcore/snapd/sandbox/cgroup"
    33  )
    34  
    35  type cmdRoutinePortalInfo struct {
    36  	clientMixin
    37  	PortalInfoOptions struct {
    38  		Pid int
    39  	} `positional-args:"true" required:"true"`
    40  }
    41  
    42  var shortRoutinePortalInfoHelp = i18n.G("Return information about a process")
    43  var longRoutinePortalInfoHelp = i18n.G(`
    44  The portal-info command returns information about a process in keyfile format.
    45  
    46  This command is used by the xdg-desktop-portal service to retrieve
    47  information about snap confined processes.
    48  `)
    49  
    50  func init() {
    51  	addRoutineCommand("portal-info", shortRoutinePortalInfoHelp, longRoutinePortalInfoHelp, func() flags.Commander {
    52  		return &cmdRoutinePortalInfo{}
    53  	}, nil, []argDesc{{
    54  		// TRANSLATORS: This needs to begin with < and end with >
    55  		name: i18n.G("<process ID>"),
    56  		// TRANSLATORS: This should not start with a lowercase letter.
    57  		desc: i18n.G("Process ID of confined app"),
    58  	}})
    59  }
    60  
    61  var (
    62  	cgroupSnapNameFromPid  = cgroup.SnapNameFromPid
    63  	apparmorSnapAppFromPid = apparmor.SnapAppFromPid
    64  )
    65  
    66  func (x *cmdRoutinePortalInfo) Execute(args []string) error {
    67  	if len(args) > 0 {
    68  		return ErrExtraArgs
    69  	}
    70  
    71  	snapName, err := cgroupSnapNameFromPid(x.PortalInfoOptions.Pid)
    72  	if err != nil {
    73  		return err
    74  	}
    75  	snap, _, err := x.client.Snap(snapName)
    76  	if err != nil {
    77  		return fmt.Errorf("cannot retrieve info for snap %q: %v", snapName, err)
    78  	}
    79  
    80  	// Try to identify the application name from AppArmor
    81  	var app *client.AppInfo
    82  	if snapName, appName, _, err := apparmorSnapAppFromPid(x.PortalInfoOptions.Pid); err == nil && snapName == snap.Name && appName != "" {
    83  		for i := range snap.Apps {
    84  			if snap.Apps[i].Name == appName {
    85  				app = &snap.Apps[i]
    86  				break
    87  			}
    88  		}
    89  	}
    90  	// As a fallback, pick an app with a desktop file, favouring
    91  	// the app named identically to the snap.
    92  	if app == nil {
    93  		for i := range snap.Apps {
    94  			if snap.Apps[i].DesktopFile != "" && (app == nil || snap.Apps[i].Name == snap.Name) {
    95  				app = &snap.Apps[i]
    96  			}
    97  		}
    98  	}
    99  
   100  	var desktopFile string
   101  	if app != nil {
   102  		desktopFile = filepath.Base(app.DesktopFile)
   103  	}
   104  
   105  	// Determine whether the snap has access to the network status
   106  	// TODO: use direct API for asking about interface being connected if
   107  	// that becomes available
   108  	connections, err := x.client.Connections(&client.ConnectionOptions{
   109  		Snap:      snap.Name,
   110  		Interface: "network-status",
   111  	})
   112  	if err != nil {
   113  		return fmt.Errorf("cannot get connections for snap %q: %v", snap.Name, err)
   114  	}
   115  	// XXX: on non-AppArmor systems, or systems where there is only a
   116  	// partial AppArmor support, the snap may still be able to access the
   117  	// network despite the 'network' interface being disconnected
   118  	var hasNetworkStatus bool
   119  	for _, conn := range connections.Established {
   120  		if conn.Plug.Snap == snap.Name && conn.Interface == "network-status" {
   121  			hasNetworkStatus = true
   122  			break
   123  		}
   124  	}
   125  
   126  	const portalInfoTemplate = `[Snap Info]
   127  InstanceName={{.Snap.Name}}
   128  {{- if .App}}
   129  AppName={{.App.Name}}
   130  {{- end}}
   131  {{- if .DesktopFile}}
   132  DesktopFile={{.DesktopFile}}
   133  {{- end}}
   134  HasNetworkStatus={{.HasNetworkStatus}}
   135  `
   136  	t := template.Must(template.New("portal-info").Parse(portalInfoTemplate))
   137  	data := struct {
   138  		Snap             *client.Snap
   139  		App              *client.AppInfo
   140  		DesktopFile      string
   141  		HasNetworkStatus bool
   142  	}{
   143  		Snap:             snap,
   144  		App:              app,
   145  		DesktopFile:      desktopFile,
   146  		HasNetworkStatus: hasNetworkStatus,
   147  	}
   148  	if err := t.Execute(Stdout, data); err != nil {
   149  		return fmt.Errorf("cannot render output template: %s", err)
   150  	}
   151  	return nil
   152  }