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mdserver_local_shared.go
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mdserver_local_shared.go
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// Copyright 2016 Keybase Inc. All rights reserved.
// Use of this source code is governed by a BSD
// license that can be found in the LICENSE file.
package libkbfs
import (
"sync"
"github.com/keybase/client/go/kbfs/kbfscodec"
"github.com/keybase/client/go/kbfs/kbfscrypto"
"github.com/keybase/client/go/kbfs/kbfsmd"
"github.com/keybase/client/go/kbfs/tlf"
"github.com/keybase/client/go/protocol/keybase1"
"github.com/pkg/errors"
"golang.org/x/net/context"
)
// TODO: Have the functions below wrap their errors.
// Helper to aid in enforcement that only specified public keys can
// access TLF metadata. mergedMasterHead can be nil, in which case
// true is returned.
func isReader(ctx context.Context, teamMemChecker kbfsmd.TeamMembershipChecker,
currentUID keybase1.UID, mergedMasterHead kbfsmd.RootMetadata,
extra kbfsmd.ExtraMetadata) (bool, error) {
h, err := mergedMasterHead.MakeBareTlfHandle(extra)
if err != nil {
return false, err
}
if h.Type() == tlf.SingleTeam {
isReader, err := teamMemChecker.IsTeamReader(
ctx, h.Writers[0].AsTeamOrBust(), currentUID,
keybase1.OfflineAvailability_NONE)
if err != nil {
return false, kbfsmd.ServerError{Err: err}
}
return isReader, nil
}
return h.IsReader(currentUID.AsUserOrTeam()), nil
}
// Helper to aid in enforcement that only specified public keys can
// access TLF metadata. mergedMasterHead can be nil, in which case
// true is returned.
func isWriterOrValidRekey(ctx context.Context,
teamMemChecker kbfsmd.TeamMembershipChecker, codec kbfscodec.Codec,
currentUID keybase1.UID, verifyingKey kbfscrypto.VerifyingKey,
mergedMasterHead, newMd kbfsmd.RootMetadata, prevExtra, extra kbfsmd.ExtraMetadata) (
bool, error) {
h, err := mergedMasterHead.MakeBareTlfHandle(prevExtra)
if err != nil {
return false, err
}
if h.Type() == tlf.SingleTeam {
isWriter, err := teamMemChecker.IsTeamWriter(
ctx, h.Writers[0].AsTeamOrBust(), currentUID, verifyingKey,
keybase1.OfflineAvailability_NONE)
if err != nil {
return false, kbfsmd.ServerError{Err: err}
}
// Team TLFs can't be rekeyed, so readers aren't ever valid.
return isWriter, nil
}
if h.IsWriter(currentUID.AsUserOrTeam()) {
return true, nil
}
if h.IsReader(currentUID.AsUserOrTeam()) {
// if this is a reader, are they acting within their
// restrictions?
return newMd.IsValidRekeyRequest(
codec, mergedMasterHead, currentUID, prevExtra, extra)
}
return false, nil
}
// mdServerLocalTruncateLockManager manages the truncate locks for a
// set of TLFs. Note that it is not goroutine-safe.
type mdServerLocalTruncateLockManager struct {
// TLF ID -> device crypt public key.
locksDb map[tlf.ID]kbfscrypto.CryptPublicKey
}
func newMDServerLocalTruncatedLockManager() mdServerLocalTruncateLockManager {
return mdServerLocalTruncateLockManager{
locksDb: make(map[tlf.ID]kbfscrypto.CryptPublicKey),
}
}
func (m mdServerLocalTruncateLockManager) truncateLock(
deviceKey kbfscrypto.CryptPublicKey, id tlf.ID) (bool, error) {
lockKey, ok := m.locksDb[id]
if !ok {
m.locksDb[id] = deviceKey
return true, nil
}
if lockKey == deviceKey {
// idempotent
return true, nil
}
// Locked by someone else.
return false, kbfsmd.ServerErrorLocked{}
}
func (m mdServerLocalTruncateLockManager) truncateUnlock(
deviceKey kbfscrypto.CryptPublicKey, id tlf.ID) (bool, error) {
lockKey, ok := m.locksDb[id]
if !ok {
// Already unlocked.
return true, nil
}
if lockKey == deviceKey {
delete(m.locksDb, id)
return true, nil
}
// Locked by someone else.
return false, kbfsmd.ServerErrorLocked{}
}
// mdServerLocalUpdateManager manages the observers for a set of TLFs
// referenced by multiple mdServerLocal instances sharing the same
// data. It is goroutine-safe.
type mdServerLocalUpdateManager struct {
// Protects observers and sessionHeads.
lock sync.Mutex
observers map[tlf.ID]map[mdServerLocal]chan<- error
sessionHeads map[tlf.ID]mdServerLocal
}
func newMDServerLocalUpdateManager() *mdServerLocalUpdateManager {
return &mdServerLocalUpdateManager{
observers: make(map[tlf.ID]map[mdServerLocal]chan<- error),
sessionHeads: make(map[tlf.ID]mdServerLocal),
}
}
func (m *mdServerLocalUpdateManager) setHead(id tlf.ID, server mdServerLocal) {
m.lock.Lock()
defer m.lock.Unlock()
m.sessionHeads[id] = server
// now fire all the observers that aren't from this session
for k, v := range m.observers[id] {
if k != server {
v <- nil
close(v)
delete(m.observers[id], k)
}
}
if len(m.observers[id]) == 0 {
delete(m.observers, id)
}
}
func (m *mdServerLocalUpdateManager) registerForUpdate(
id tlf.ID, currHead, currMergedHeadRev kbfsmd.Revision,
server mdServerLocal) <-chan error {
m.lock.Lock()
defer m.lock.Unlock()
c := make(chan error, 1)
if currMergedHeadRev > currHead && server != m.sessionHeads[id] {
c <- nil
close(c)
return c
}
if _, ok := m.observers[id]; !ok {
m.observers[id] = make(map[mdServerLocal]chan<- error)
}
// Otherwise, this is a legit observer. This assumes that each
// client will be using a unique instance of MDServerLocal.
if _, ok := m.observers[id][server]; ok {
// If the local node registers something twice, it indicates a
// fatal bug. Note that in the real MDServer implementation,
// we should allow this, in order to make the RPC properly
// idempotent.
panic(errors.Errorf("Attempted double-registration for MDServerLocal %v",
server))
}
m.observers[id][server] = c
return c
}
func (m *mdServerLocalUpdateManager) cancel(id tlf.ID, server mdServerLocal) {
m.lock.Lock()
defer m.lock.Unlock()
// Cancel the registration for this server only.
for k, v := range m.observers[id] {
if k == server {
v <- errors.New("Registration canceled")
close(v)
delete(m.observers[id], k)
}
}
if len(m.observers[id]) == 0 {
delete(m.observers, id)
}
}
type keyBundleGetter func(tlf.ID, kbfsmd.TLFWriterKeyBundleID, kbfsmd.TLFReaderKeyBundleID) (
*kbfsmd.TLFWriterKeyBundleV3, *kbfsmd.TLFReaderKeyBundleV3, error)
func getExtraMetadata(kbg keyBundleGetter, brmd kbfsmd.RootMetadata) (kbfsmd.ExtraMetadata, error) {
tlfID := brmd.TlfID()
wkbID := brmd.GetTLFWriterKeyBundleID()
rkbID := brmd.GetTLFReaderKeyBundleID()
if (wkbID == kbfsmd.TLFWriterKeyBundleID{}) !=
(rkbID == kbfsmd.TLFReaderKeyBundleID{}) {
return nil, errors.Errorf(
"wkbID is empty (%t) != rkbID is empty (%t)",
wkbID == kbfsmd.TLFWriterKeyBundleID{},
rkbID == kbfsmd.TLFReaderKeyBundleID{})
}
if wkbID == (kbfsmd.TLFWriterKeyBundleID{}) {
return nil, nil
}
wkb, rkb, err := kbg(tlfID, wkbID, rkbID)
if err != nil {
return nil, err
}
return kbfsmd.NewExtraMetadataV3(*wkb, *rkb, false, false), nil
}