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helpers.go
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helpers.go
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// -*- Mode: Go; indent-tabs-mode: t -*-
/*
* Copyright (C) 2016-2020 Canonical Ltd
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 3 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
package ifacestate
import (
"bytes"
"encoding/json"
"fmt"
"os"
"sort"
"strings"
"github.com/snapcore/snapd/asserts"
"github.com/snapcore/snapd/dirs"
"github.com/snapcore/snapd/interfaces"
"github.com/snapcore/snapd/interfaces/backends"
"github.com/snapcore/snapd/interfaces/builtin"
"github.com/snapcore/snapd/interfaces/policy"
"github.com/snapcore/snapd/interfaces/utils"
"github.com/snapcore/snapd/jsonutil"
"github.com/snapcore/snapd/logger"
"github.com/snapcore/snapd/overlord/assertstate"
"github.com/snapcore/snapd/overlord/snapstate"
"github.com/snapcore/snapd/overlord/state"
"github.com/snapcore/snapd/snap"
"github.com/snapcore/snapd/timings"
)
func (m *InterfaceManager) selectInterfaceMapper(snaps []*snap.Info) {
for _, snapInfo := range snaps {
if snapInfo.Type() == snap.TypeSnapd {
mapper = &CoreSnapdSystemMapper{}
break
}
}
}
func (m *InterfaceManager) addInterfaces(extra []interfaces.Interface) error {
for _, iface := range builtin.Interfaces() {
if err := m.repo.AddInterface(iface); err != nil {
return err
}
}
for _, iface := range extra {
if err := m.repo.AddInterface(iface); err != nil {
return err
}
}
return nil
}
func (m *InterfaceManager) addBackends(extra []interfaces.SecurityBackend) error {
opts := interfaces.SecurityBackendOptions{Preseed: m.preseed}
for _, backend := range backends.All {
if err := backend.Initialize(&opts); err != nil {
return err
}
if err := m.repo.AddBackend(backend); err != nil {
return err
}
}
for _, backend := range extra {
if err := backend.Initialize(&opts); err != nil {
return err
}
if err := m.repo.AddBackend(backend); err != nil {
return err
}
}
return nil
}
func (m *InterfaceManager) addSnaps(snaps []*snap.Info) error {
for _, snapInfo := range snaps {
if err := addImplicitSlots(m.state, snapInfo); err != nil {
return err
}
if err := m.repo.AddSnap(snapInfo); err != nil {
logger.Noticef("cannot add snap %q to interface repository: %s", snapInfo.InstanceName(), err)
}
}
return nil
}
func profilesNeedRegenerationImpl() bool {
mismatch, err := interfaces.SystemKeyMismatch()
if err != nil {
logger.Noticef("error trying to compare the snap system key: %v", err)
return true
}
return mismatch
}
var profilesNeedRegeneration = profilesNeedRegenerationImpl
var writeSystemKey = interfaces.WriteSystemKey
// regenerateAllSecurityProfiles will regenerate all security profiles.
func (m *InterfaceManager) regenerateAllSecurityProfiles(tm timings.Measurer) error {
// Get all the security backends
securityBackends := m.repo.Backends()
// Get all the snap infos
snaps, err := snapsWithSecurityProfiles(m.state)
if err != nil {
return err
}
// Add implicit slots to all snaps
for _, snapInfo := range snaps {
if err := addImplicitSlots(m.state, snapInfo); err != nil {
return err
}
}
// The reason the system key is unlinked is to prevent snapd from believing
// that an old system key is valid and represents security setup
// established in the system. If snapd is reverted following a failed
// startup then system key may match the system key that used to be on disk
// but some of the system security may have been changed by the new snapd,
// the one that was reverted. Unlinking avoids such possibility, forcing
// old snapd to re-establish proper security view.
shouldWriteSystemKey := true
os.Remove(dirs.SnapSystemKeyFile)
confinementOpts := func(snapName string) interfaces.ConfinementOptions {
var snapst snapstate.SnapState
if err := snapstate.Get(m.state, snapName, &snapst); err != nil {
logger.Noticef("cannot get state of snap %q: %s", snapName, err)
}
return confinementOptions(snapst.Flags)
}
// For each backend:
for _, backend := range securityBackends {
if backend.Name() == "" {
continue // Test backends have no name, skip them to simplify testing.
}
if errors := interfaces.SetupMany(m.repo, backend, snaps, confinementOpts, tm); len(errors) > 0 {
logger.Noticef("cannot regenerate %s profiles", backend.Name())
for _, err := range errors {
logger.Noticef(err.Error())
}
shouldWriteSystemKey = false
}
}
if shouldWriteSystemKey {
if err := writeSystemKey(); err != nil {
logger.Noticef("cannot write system key: %v", err)
}
}
return nil
}
// renameCorePlugConnection renames one connection from "core-support" plug to
// slot so that the plug name is "core-support-plug" while the slot is
// unchanged. This matches a change introduced in 2.24, where the core snap no
// longer has the "core-support" plug as that was clashing with the slot with
// the same name.
func (m *InterfaceManager) renameCorePlugConnection() error {
conns, err := getConns(m.state)
if err != nil {
return err
}
const oldPlugName = "core-support"
const newPlugName = "core-support-plug"
// old connection, note that slotRef is the same in both
slotRef := interfaces.SlotRef{Snap: "core", Name: oldPlugName}
oldPlugRef := interfaces.PlugRef{Snap: "core", Name: oldPlugName}
oldConnRef := interfaces.ConnRef{PlugRef: oldPlugRef, SlotRef: slotRef}
oldID := oldConnRef.ID()
// if the old connection is saved, replace it with the new connection
if cState, ok := conns[oldID]; ok {
newPlugRef := interfaces.PlugRef{Snap: "core", Name: newPlugName}
newConnRef := interfaces.ConnRef{PlugRef: newPlugRef, SlotRef: slotRef}
newID := newConnRef.ID()
delete(conns, oldID)
conns[newID] = cState
setConns(m.state, conns)
}
return nil
}
// removeStaleConnections removes stale connections left by some older versions of snapd.
// Connection is considered stale if the snap on either end of the connection doesn't exist anymore.
// XXX: this code should eventually go away.
var removeStaleConnections = func(st *state.State) error {
conns, err := getConns(st)
if err != nil {
return err
}
var staleConns []string
for id := range conns {
connRef, err := interfaces.ParseConnRef(id)
if err != nil {
return err
}
var snapst snapstate.SnapState
if err := snapstate.Get(st, connRef.PlugRef.Snap, &snapst); err != nil {
if err != state.ErrNoState {
return err
}
staleConns = append(staleConns, id)
continue
}
if err := snapstate.Get(st, connRef.SlotRef.Snap, &snapst); err != nil {
if err != state.ErrNoState {
return err
}
staleConns = append(staleConns, id)
continue
}
}
if len(staleConns) > 0 {
for _, id := range staleConns {
delete(conns, id)
}
setConns(st, conns)
logger.Noticef("removed stale connections: %s", strings.Join(staleConns, ", "))
}
return nil
}
// reloadConnections reloads connections stored in the state in the repository.
// Using non-empty snapName the operation can be scoped to connections
// affecting a given snap.
//
// The return value is the list of affected snap names.
func (m *InterfaceManager) reloadConnections(snapName string) ([]string, error) {
conns, err := getConns(m.state)
if err != nil {
return nil, err
}
connStateChanged := false
affected := make(map[string]bool)
for connId, connState := range conns {
// Skip entries that just mark a connection as undesired. Those don't
// carry attributes that can go stale. In the same spirit, skip
// information about hotplug connections that don't have the associated
// hotplug hardware.
if connState.Undesired || connState.HotplugGone {
continue
}
connRef, err := interfaces.ParseConnRef(connId)
if err != nil {
return nil, err
}
// Apply filtering, this allows us to reload only a subset of
// connections (and similarly, refresh the static attributes of only a
// subset of connections).
if snapName != "" && connRef.PlugRef.Snap != snapName && connRef.SlotRef.Snap != snapName {
continue
}
plugInfo := m.repo.Plug(connRef.PlugRef.Snap, connRef.PlugRef.Name)
slotInfo := m.repo.Slot(connRef.SlotRef.Snap, connRef.SlotRef.Name)
// The connection refers to a plug or slot that doesn't exist anymore, e.g. because of a refresh
// to a new snap revision that doesn't have the given plug/slot.
if plugInfo == nil || slotInfo == nil {
// automatic connection can simply be removed (it will be re-created automatically if needed)
// as long as it wasn't disconnected manually; note that undesired flag is taken care of at
// the beginning of the loop.
if connState.Auto && !connState.ByGadget && connState.Interface != "core-support" {
delete(conns, connId)
connStateChanged = true
}
// otherwise keep it and silently ignore, e.g. in case of a revert.
continue
}
var updateStaticAttrs bool
staticPlugAttrs := connState.StaticPlugAttrs
staticSlotAttrs := connState.StaticSlotAttrs
// XXX: Refresh the copy of the static connection attributes for "content" interface as long
// as its "content" attribute
// This is a partial and temporary solution to https://bugs.launchpad.net/snapd/+bug/1825883
if plugInfo.Interface == "content" {
var plugContent, slotContent string
plugInfo.Attr("content", &plugContent)
slotInfo.Attr("content", &slotContent)
if plugContent != "" && plugContent == slotContent {
staticPlugAttrs = utils.NormalizeInterfaceAttributes(plugInfo.Attrs).(map[string]interface{})
staticSlotAttrs = utils.NormalizeInterfaceAttributes(slotInfo.Attrs).(map[string]interface{})
updateStaticAttrs = true
} else {
logger.Noticef("cannot refresh static attributes of the connection %q", connId)
}
}
// Note: reloaded connections are not checked against policy again, and also we don't call BeforeConnect* methods on them.
if _, err := m.repo.Connect(connRef, staticPlugAttrs, connState.DynamicPlugAttrs, staticSlotAttrs, connState.DynamicSlotAttrs, nil); err != nil {
logger.Noticef("%s", err)
} else {
// If the connection succeeded update the connection state and keep
// track of the snaps that were affected.
affected[connRef.PlugRef.Snap] = true
affected[connRef.SlotRef.Snap] = true
if updateStaticAttrs {
connState.StaticPlugAttrs = staticPlugAttrs
connState.StaticSlotAttrs = staticSlotAttrs
connStateChanged = true
}
}
}
if connStateChanged {
setConns(m.state, conns)
}
result := make([]string, 0, len(affected))
for name := range affected {
result = append(result, name)
}
return result, nil
}
// removeConnections disconnects all connections of the snap in the repo. It should only be used if the snap
// has no connections in the state. State must be locked by the caller.
func (m *InterfaceManager) removeConnections(snapName string) error {
conns, err := getConns(m.state)
if err != nil {
return err
}
for id := range conns {
connRef, err := interfaces.ParseConnRef(id)
if err != nil {
return err
}
if connRef.PlugRef.Snap == snapName || connRef.SlotRef.Snap == snapName {
return fmt.Errorf("internal error: cannot remove connections of snap %s from the repository while its connections are present in the state", snapName)
}
}
repoConns, err := m.repo.Connections(snapName)
if err != nil {
return fmt.Errorf("internal error: %v", err)
}
for _, conn := range repoConns {
if err := m.repo.Disconnect(conn.PlugRef.Snap, conn.PlugRef.Name, conn.SlotRef.Snap, conn.SlotRef.Name); err != nil {
return fmt.Errorf("internal error: %v", err)
}
}
return nil
}
func (m *InterfaceManager) setupSecurityByBackend(task *state.Task, snaps []*snap.Info, opts []interfaces.ConfinementOptions, tm timings.Measurer) error {
if len(snaps) != len(opts) {
return fmt.Errorf("internal error: setupSecurityByBackend received an unexpected number of snaps (expected: %d, got %d)", len(opts), len(snaps))
}
confOpts := make(map[string]interfaces.ConfinementOptions, len(snaps))
for i, snapInfo := range snaps {
confOpts[snapInfo.InstanceName()] = opts[i]
}
st := task.State()
st.Unlock()
defer st.Lock()
// Setup all affected snaps, start with the most important security
// backend and run it for all snaps. See LP: 1802581
for _, backend := range m.repo.Backends() {
errs := interfaces.SetupMany(m.repo, backend, snaps, func(snapName string) interfaces.ConfinementOptions {
return confOpts[snapName]
}, tm)
if len(errs) > 0 {
// SetupMany processes all profiles and returns all encountered errors; report just the first one
return errs[0]
}
}
return nil
}
func (m *InterfaceManager) setupSnapSecurity(task *state.Task, snapInfo *snap.Info, opts interfaces.ConfinementOptions, tm timings.Measurer) error {
return m.setupSecurityByBackend(task, []*snap.Info{snapInfo}, []interfaces.ConfinementOptions{opts}, tm)
}
func (m *InterfaceManager) removeSnapSecurity(task *state.Task, instanceName string) error {
st := task.State()
for _, backend := range m.repo.Backends() {
st.Unlock()
err := backend.Remove(instanceName)
st.Lock()
if err != nil {
task.Errorf("cannot setup %s for snap %q: %s", backend.Name(), instanceName, err)
return err
}
}
return nil
}
func addHotplugSlot(st *state.State, repo *interfaces.Repository, stateSlots map[string]*HotplugSlotInfo, iface interfaces.Interface, slot *snap.SlotInfo) error {
if slot.HotplugKey == "" {
return fmt.Errorf("internal error: cannot store slot %q, not a hotplug slot", slot.Name)
}
if iface, ok := iface.(interfaces.SlotSanitizer); ok {
if err := iface.BeforePrepareSlot(slot); err != nil {
return fmt.Errorf("cannot sanitize hotplug slot %q for interface %s: %s", slot.Name, slot.Interface, err)
}
}
if err := repo.AddSlot(slot); err != nil {
return fmt.Errorf("cannot add hotplug slot %q for interface %s: %s", slot.Name, slot.Interface, err)
}
stateSlots[slot.Name] = &HotplugSlotInfo{
Name: slot.Name,
Interface: slot.Interface,
StaticAttrs: slot.Attrs,
HotplugKey: slot.HotplugKey,
HotplugGone: false,
}
setHotplugSlots(st, stateSlots)
logger.Debugf("added hotplug slot %s:%s of interface %s, hotplug key %q", slot.Snap.InstanceName(), slot.Name, slot.Interface, slot.HotplugKey)
return nil
}
type connState struct {
Auto bool `json:"auto,omitempty"`
ByGadget bool `json:"by-gadget,omitempty"`
Interface string `json:"interface,omitempty"`
// Undesired tracks connections that were manually disconnected after being auto-connected,
// so that they are not automatically reconnected again in the future.
Undesired bool `json:"undesired,omitempty"`
StaticPlugAttrs map[string]interface{} `json:"plug-static,omitempty"`
DynamicPlugAttrs map[string]interface{} `json:"plug-dynamic,omitempty"`
StaticSlotAttrs map[string]interface{} `json:"slot-static,omitempty"`
DynamicSlotAttrs map[string]interface{} `json:"slot-dynamic,omitempty"`
// Hotplug-related attributes: HotplugGone indicates a connection that
// disappeared because the device was removed, but may potentially be
// restored in the future if we see the device again. HotplugKey is the
// key of the associated device; it's empty for connections of regular
// slots.
HotplugGone bool `json:"hotplug-gone,omitempty"`
HotplugKey snap.HotplugKey `json:"hotplug-key,omitempty"`
}
type gadgetConnect struct {
st *state.State
task *state.Task
repo *interfaces.Repository
instanceName string
deviceCtx snapstate.DeviceContext
}
func newGadgetConnect(s *state.State, task *state.Task, repo *interfaces.Repository, instanceName string, deviceCtx snapstate.DeviceContext) *gadgetConnect {
return &gadgetConnect{
st: s,
task: task,
repo: repo,
instanceName: instanceName,
deviceCtx: deviceCtx,
}
}
// addGadgetConnections adds to newconns any applicable connections
// from the gadget connections stanza.
// conflictError is called to handle checkAutoconnectConflicts errors.
func (gc *gadgetConnect) addGadgetConnections(newconns map[string]*interfaces.ConnRef, conns map[string]*connState, conflictError func(*state.Retry, error) error) error {
var seeded bool
err := gc.st.Get("seeded", &seeded)
if err != nil && err != state.ErrNoState {
return err
}
// we apply gadget connections only during seeding or a remodeling
if seeded && !gc.deviceCtx.ForRemodeling() {
return nil
}
task := gc.task
snapName := gc.instanceName
var snapst snapstate.SnapState
if err := snapstate.Get(gc.st, snapName, &snapst); err != nil {
return err
}
snapInfo, err := snapst.CurrentInfo()
if err != nil {
return err
}
snapID := snapInfo.SnapID
if snapID == "" {
// not a snap-id identifiable snap, skip
return nil
}
gconns, err := snapstate.GadgetConnections(gc.st, gc.deviceCtx)
if err != nil {
if err == state.ErrNoState {
// no gadget yet, nothing to do
return nil
}
return err
}
// consider the gadget connect instructions
for _, gconn := range gconns {
var plugSnapName, slotSnapName string
if gconn.Plug.SnapID == snapID {
plugSnapName = snapName
}
if gconn.Slot.SnapID == snapID {
slotSnapName = snapName
}
if plugSnapName == "" && slotSnapName == "" {
// no match, nothing to do
continue
}
if plugSnapName == "" {
var err error
plugSnapName, err = resolveSnapIDToName(gc.st, gconn.Plug.SnapID)
if err != nil {
return err
}
}
plug := gc.repo.Plug(plugSnapName, gconn.Plug.Plug)
if plug == nil {
task.Logf("gadget connections: ignoring missing plug %s:%s", gconn.Plug.SnapID, gconn.Plug.Plug)
continue
}
if slotSnapName == "" {
var err error
slotSnapName, err = resolveSnapIDToName(gc.st, gconn.Slot.SnapID)
if err != nil {
return err
}
}
slot := gc.repo.Slot(slotSnapName, gconn.Slot.Slot)
if slot == nil {
task.Logf("gadget connections: ignoring missing slot %s:%s", gconn.Slot.SnapID, gconn.Slot.Slot)
continue
}
if err := addNewConnection(gc.st, task, newconns, conns, plug, slot, conflictError); err != nil {
return err
}
}
return nil
}
func addNewConnection(st *state.State, task *state.Task, newconns map[string]*interfaces.ConnRef, conns map[string]*connState, plug *snap.PlugInfo, slot *snap.SlotInfo, conflictError func(*state.Retry, error) error) error {
connRef := interfaces.NewConnRef(plug, slot)
key := connRef.ID()
if _, ok := conns[key]; ok {
// Suggested connection already exist (or has
// Undesired flag set) so don't clobber it.
// NOTE: we don't log anything here as this is
// a normal and common condition.
return nil
}
if _, ok := newconns[key]; ok {
return nil
}
if task.Kind() == "auto-connect" {
ignore, err := findSymmetricAutoconnectTask(st, plug.Snap.InstanceName(), slot.Snap.InstanceName(), task)
if err != nil {
return err
}
if ignore {
return nil
}
}
if err := checkAutoconnectConflicts(st, task, plug.Snap.InstanceName(), slot.Snap.InstanceName()); err != nil {
retry, _ := err.(*state.Retry)
return conflictError(retry, err)
}
newconns[key] = connRef
return nil
}
type autoConnectChecker struct {
st *state.State
task *state.Task
repo *interfaces.Repository
deviceCtx snapstate.DeviceContext
cache map[string]*asserts.SnapDeclaration
baseDecl *asserts.BaseDeclaration
}
func newAutoConnectChecker(s *state.State, task *state.Task, repo *interfaces.Repository, deviceCtx snapstate.DeviceContext) (*autoConnectChecker, error) {
baseDecl, err := assertstate.BaseDeclaration(s)
if err != nil {
return nil, fmt.Errorf("internal error: cannot find base declaration: %v", err)
}
return &autoConnectChecker{
st: s,
task: task,
repo: repo,
deviceCtx: deviceCtx,
cache: make(map[string]*asserts.SnapDeclaration),
baseDecl: baseDecl,
}, nil
}
func (c *autoConnectChecker) snapDeclaration(snapID string) (*asserts.SnapDeclaration, error) {
snapDecl := c.cache[snapID]
if snapDecl != nil {
return snapDecl, nil
}
snapDecl, err := assertstate.SnapDeclaration(c.st, snapID)
if err != nil {
return nil, err
}
c.cache[snapID] = snapDecl
return snapDecl, nil
}
func (c *autoConnectChecker) check(plug *interfaces.ConnectedPlug, slot *interfaces.ConnectedSlot) (bool, interfaces.SideArity, error) {
modelAs := c.deviceCtx.Model()
var storeAs *asserts.Store
if modelAs.Store() != "" {
var err error
storeAs, err = assertstate.Store(c.st, modelAs.Store())
if err != nil && !asserts.IsNotFound(err) {
return false, nil, err
}
}
var plugDecl *asserts.SnapDeclaration
if plug.Snap().SnapID != "" {
var err error
plugDecl, err = c.snapDeclaration(plug.Snap().SnapID)
if err != nil {
logger.Noticef("error: cannot find snap declaration for %q: %v", plug.Snap().InstanceName(), err)
return false, nil, nil
}
}
var slotDecl *asserts.SnapDeclaration
if slot.Snap().SnapID != "" {
var err error
slotDecl, err = c.snapDeclaration(slot.Snap().SnapID)
if err != nil {
logger.Noticef("error: cannot find snap declaration for %q: %v", slot.Snap().InstanceName(), err)
return false, nil, nil
}
}
// check the connection against the declarations' rules
ic := policy.ConnectCandidate{
Plug: plug,
PlugSnapDeclaration: plugDecl,
Slot: slot,
SlotSnapDeclaration: slotDecl,
BaseDeclaration: c.baseDecl,
Model: modelAs,
Store: storeAs,
}
arity, err := ic.CheckAutoConnect()
if err == nil {
return true, arity, nil
}
return false, nil, nil
}
// filterUbuntuCoreSlots filters out any ubuntu-core slots,
// if there are both ubuntu-core and core slots. This would occur
// during a ubuntu-core -> core transition.
func filterUbuntuCoreSlots(candidates []*snap.SlotInfo, arities []interfaces.SideArity) ([]*snap.SlotInfo, []interfaces.SideArity) {
hasCore := false
hasUbuntuCore := false
var withoutUbuntuCore []*snap.SlotInfo
var withoutUbuntuCoreArities []interfaces.SideArity
for i, candSlot := range candidates {
switch candSlot.Snap.InstanceName() {
case "ubuntu-core":
if !hasUbuntuCore {
hasUbuntuCore = true
withoutUbuntuCore = append(withoutUbuntuCore, candidates[:i]...)
withoutUbuntuCoreArities = append(withoutUbuntuCoreArities, arities[:i]...)
}
case "core":
hasCore = true
fallthrough
default:
if hasUbuntuCore {
withoutUbuntuCore = append(withoutUbuntuCore, candSlot)
withoutUbuntuCoreArities = append(withoutUbuntuCoreArities, arities[i])
}
}
}
if hasCore && hasUbuntuCore {
candidates = withoutUbuntuCore
arities = withoutUbuntuCoreArities
}
return candidates, arities
}
// addAutoConnections adds to newconns any applicable auto-connections
// from the given plugs to corresponding candidates slots after
// filtering them with optional filter and against preexisting
// conns. cannotAutoConnectLog is called to build a log message in
// case no applicable pair was found. conflictError is called
// to handle checkAutoconnectConflicts errors.
func (c *autoConnectChecker) addAutoConnections(newconns map[string]*interfaces.ConnRef, plugs []*snap.PlugInfo, filter func([]*snap.SlotInfo) []*snap.SlotInfo, conns map[string]*connState, cannotAutoConnectLog func(plug *snap.PlugInfo, candRefs []string) string, conflictError func(*state.Retry, error) error) error {
for _, plug := range plugs {
candSlots, arities := c.repo.AutoConnectCandidateSlots(plug.Snap.InstanceName(), plug.Name, c.check)
if len(candSlots) == 0 {
continue
}
// If we are in a core transition we may have both the
// old ubuntu-core snap and the new core snap
// providing the same interface. In that situation we
// want to ignore any candidates in ubuntu-core and
// simply go with those from the new core snap.
candSlots, arities = filterUbuntuCoreSlots(candSlots, arities)
applicable := candSlots
// candidate arity check
for _, arity := range arities {
if !arity.SlotsPerPlugAny() {
// ATM not any (*) => none or exactly one
if len(candSlots) != 1 {
applicable = nil
}
break
}
}
if filter != nil {
applicable = filter(applicable)
}
if len(applicable) == 0 {
crefs := make([]string, len(candSlots))
for i, candidate := range candSlots {
crefs[i] = candidate.String()
}
c.task.Logf(cannotAutoConnectLog(plug, crefs))
continue
}
for _, slot := range applicable {
if err := addNewConnection(c.st, c.task, newconns, conns, plug, slot, conflictError); err != nil {
return err
}
}
}
return nil
}
type connectChecker struct {
st *state.State
deviceCtx snapstate.DeviceContext
baseDecl *asserts.BaseDeclaration
}
func newConnectChecker(s *state.State, deviceCtx snapstate.DeviceContext) (*connectChecker, error) {
baseDecl, err := assertstate.BaseDeclaration(s)
if err != nil {
return nil, fmt.Errorf("internal error: cannot find base declaration: %v", err)
}
return &connectChecker{
st: s,
deviceCtx: deviceCtx,
baseDecl: baseDecl,
}, nil
}
func (c *connectChecker) check(plug *interfaces.ConnectedPlug, slot *interfaces.ConnectedSlot) (bool, error) {
modelAs := c.deviceCtx.Model()
var storeAs *asserts.Store
if modelAs.Store() != "" {
var err error
storeAs, err = assertstate.Store(c.st, modelAs.Store())
if err != nil && !asserts.IsNotFound(err) {
return false, err
}
}
var plugDecl *asserts.SnapDeclaration
if plug.Snap().SnapID != "" {
var err error
plugDecl, err = assertstate.SnapDeclaration(c.st, plug.Snap().SnapID)
if err != nil {
return false, fmt.Errorf("cannot find snap declaration for %q: %v", plug.Snap().InstanceName(), err)
}
}
var slotDecl *asserts.SnapDeclaration
if slot.Snap().SnapID != "" {
var err error
slotDecl, err = assertstate.SnapDeclaration(c.st, slot.Snap().SnapID)
if err != nil {
return false, fmt.Errorf("cannot find snap declaration for %q: %v", slot.Snap().InstanceName(), err)
}
}
// check the connection against the declarations' rules
ic := policy.ConnectCandidate{
Plug: plug,
PlugSnapDeclaration: plugDecl,
Slot: slot,
SlotSnapDeclaration: slotDecl,
BaseDeclaration: c.baseDecl,
Model: modelAs,
Store: storeAs,
}
// if either of plug or slot snaps don't have a declaration it
// means they were installed with "dangerous", so the security
// check should be skipped at this point.
if plugDecl != nil && slotDecl != nil {
if err := ic.Check(); err != nil {
return false, err
}
}
return true, nil
}
func getPlugAndSlotRefs(task *state.Task) (interfaces.PlugRef, interfaces.SlotRef, error) {
var plugRef interfaces.PlugRef
var slotRef interfaces.SlotRef
if err := task.Get("plug", &plugRef); err != nil {
return plugRef, slotRef, err
}
if err := task.Get("slot", &slotRef); err != nil {
return plugRef, slotRef, err
}
return plugRef, slotRef, nil
}
// getConns returns information about connections from the state.
//
// Connections are transparently re-mapped according to remapIncomingConnRef
func getConns(st *state.State) (conns map[string]*connState, err error) {
var raw *json.RawMessage
err = st.Get("conns", &raw)
if err != nil && err != state.ErrNoState {
return nil, fmt.Errorf("cannot obtain raw data about existing connections: %s", err)
}
if raw != nil {
err = jsonutil.DecodeWithNumber(bytes.NewReader(*raw), &conns)
if err != nil {
return nil, fmt.Errorf("cannot decode data about existing connections: %s", err)
}
}
if conns == nil {
conns = make(map[string]*connState)
}
remapped := make(map[string]*connState, len(conns))
for id, cstate := range conns {
cref, err := interfaces.ParseConnRef(id)
if err != nil {
return nil, err
}
cref.PlugRef.Snap = RemapSnapFromState(cref.PlugRef.Snap)
cref.SlotRef.Snap = RemapSnapFromState(cref.SlotRef.Snap)
cstate.StaticSlotAttrs = utils.NormalizeInterfaceAttributes(cstate.StaticSlotAttrs).(map[string]interface{})
cstate.DynamicSlotAttrs = utils.NormalizeInterfaceAttributes(cstate.DynamicSlotAttrs).(map[string]interface{})
cstate.StaticPlugAttrs = utils.NormalizeInterfaceAttributes(cstate.StaticPlugAttrs).(map[string]interface{})
cstate.DynamicPlugAttrs = utils.NormalizeInterfaceAttributes(cstate.DynamicPlugAttrs).(map[string]interface{})
remapped[cref.ID()] = cstate
}
return remapped, nil
}
// setConns sets information about connections in the state.
//
// Connections are transparently re-mapped according to remapOutgoingConnRef
func setConns(st *state.State, conns map[string]*connState) {
remapped := make(map[string]*connState, len(conns))
for id, cstate := range conns {
cref, err := interfaces.ParseConnRef(id)
if err != nil {
// We cannot fail here
panic(err)
}
cref.PlugRef.Snap = RemapSnapToState(cref.PlugRef.Snap)
cref.SlotRef.Snap = RemapSnapToState(cref.SlotRef.Snap)
remapped[cref.ID()] = cstate
}
st.Set("conns", remapped)
}
// snapsWithSecurityProfiles returns all snaps that have active
// security profiles: these are either snaps that are active, or about
// to be active (pending link-snap) with a done setup-profiles
func snapsWithSecurityProfiles(st *state.State) ([]*snap.Info, error) {
infos, err := snapstate.ActiveInfos(st)
if err != nil {
return nil, err
}
seen := make(map[string]bool, len(infos))
for _, info := range infos {
seen[info.InstanceName()] = true
}
for _, t := range st.Tasks() {
if t.Kind() != "link-snap" || t.Status().Ready() {
continue
}
snapsup, err := snapstate.TaskSnapSetup(t)
if err != nil {
return nil, err
}
instanceName := snapsup.InstanceName()
if seen[instanceName] {
continue
}
doneProfiles := false
for _, t1 := range t.WaitTasks() {
if t1.Kind() == "setup-profiles" && t1.Status() == state.DoneStatus {
snapsup1, err := snapstate.TaskSnapSetup(t1)
if err != nil {
return nil, err
}
if snapsup1.InstanceName() == instanceName {
doneProfiles = true
break
}
}
}
if !doneProfiles {
continue
}
seen[instanceName] = true
snapInfo, err := snap.ReadInfo(instanceName, snapsup.SideInfo)
if err != nil {
logger.Noticef("cannot retrieve info for snap %q: %s", instanceName, err)
continue
}
infos = append(infos, snapInfo)
}
return infos, nil
}
func resolveSnapIDToName(st *state.State, snapID string) (name string, err error) {
if snapID == "system" {
// Resolve the system nickname to a concrete snap.
return mapper.RemapSnapFromRequest(snapID), nil
}
decl, err := assertstate.SnapDeclaration(st, snapID)
if asserts.IsNotFound(err) {
return "", nil
}
if err != nil {
return "", err
}
return decl.SnapName(), nil
}
// SnapMapper offers APIs for re-mapping snap names in interfaces and the
// configuration system. The mapper is designed to apply transformations around
// the edges of snapd (state interactions and API interactions) to offer one
// view on the inside of snapd and another view on the outside.
type SnapMapper interface {
// re-map functions for loading and saving objects in the state.
RemapSnapFromState(snapName string) string
RemapSnapToState(snapName string) string
// RamapSnapFromRequest can replace snap names in API requests.
// There is no corresponding mapping function for API responses anymore.
// The API responses always reflect the real system state.
RemapSnapFromRequest(snapName string) string
// Returns actual name of the system snap.
SystemSnapName() string
}