mirror of
https://github.com/ceph/ceph-csi.git
synced 2024-12-22 13:00:19 +00:00
446 lines
12 KiB
Go
446 lines
12 KiB
Go
// Copyright 2014 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package webdav
|
|
|
|
import (
|
|
"container/heap"
|
|
"errors"
|
|
"strconv"
|
|
"strings"
|
|
"sync"
|
|
"time"
|
|
)
|
|
|
|
var (
|
|
// ErrConfirmationFailed is returned by a LockSystem's Confirm method.
|
|
ErrConfirmationFailed = errors.New("webdav: confirmation failed")
|
|
// ErrForbidden is returned by a LockSystem's Unlock method.
|
|
ErrForbidden = errors.New("webdav: forbidden")
|
|
// ErrLocked is returned by a LockSystem's Create, Refresh and Unlock methods.
|
|
ErrLocked = errors.New("webdav: locked")
|
|
// ErrNoSuchLock is returned by a LockSystem's Refresh and Unlock methods.
|
|
ErrNoSuchLock = errors.New("webdav: no such lock")
|
|
)
|
|
|
|
// Condition can match a WebDAV resource, based on a token or ETag.
|
|
// Exactly one of Token and ETag should be non-empty.
|
|
type Condition struct {
|
|
Not bool
|
|
Token string
|
|
ETag string
|
|
}
|
|
|
|
// LockSystem manages access to a collection of named resources. The elements
|
|
// in a lock name are separated by slash ('/', U+002F) characters, regardless
|
|
// of host operating system convention.
|
|
type LockSystem interface {
|
|
// Confirm confirms that the caller can claim all of the locks specified by
|
|
// the given conditions, and that holding the union of all of those locks
|
|
// gives exclusive access to all of the named resources. Up to two resources
|
|
// can be named. Empty names are ignored.
|
|
//
|
|
// Exactly one of release and err will be non-nil. If release is non-nil,
|
|
// all of the requested locks are held until release is called. Calling
|
|
// release does not unlock the lock, in the WebDAV UNLOCK sense, but once
|
|
// Confirm has confirmed that a lock claim is valid, that lock cannot be
|
|
// Confirmed again until it has been released.
|
|
//
|
|
// If Confirm returns ErrConfirmationFailed then the Handler will continue
|
|
// to try any other set of locks presented (a WebDAV HTTP request can
|
|
// present more than one set of locks). If it returns any other non-nil
|
|
// error, the Handler will write a "500 Internal Server Error" HTTP status.
|
|
Confirm(now time.Time, name0, name1 string, conditions ...Condition) (release func(), err error)
|
|
|
|
// Create creates a lock with the given depth, duration, owner and root
|
|
// (name). The depth will either be negative (meaning infinite) or zero.
|
|
//
|
|
// If Create returns ErrLocked then the Handler will write a "423 Locked"
|
|
// HTTP status. If it returns any other non-nil error, the Handler will
|
|
// write a "500 Internal Server Error" HTTP status.
|
|
//
|
|
// See http://www.webdav.org/specs/rfc4918.html#rfc.section.9.10.6 for
|
|
// when to use each error.
|
|
//
|
|
// The token returned identifies the created lock. It should be an absolute
|
|
// URI as defined by RFC 3986, Section 4.3. In particular, it should not
|
|
// contain whitespace.
|
|
Create(now time.Time, details LockDetails) (token string, err error)
|
|
|
|
// Refresh refreshes the lock with the given token.
|
|
//
|
|
// If Refresh returns ErrLocked then the Handler will write a "423 Locked"
|
|
// HTTP Status. If Refresh returns ErrNoSuchLock then the Handler will write
|
|
// a "412 Precondition Failed" HTTP Status. If it returns any other non-nil
|
|
// error, the Handler will write a "500 Internal Server Error" HTTP status.
|
|
//
|
|
// See http://www.webdav.org/specs/rfc4918.html#rfc.section.9.10.6 for
|
|
// when to use each error.
|
|
Refresh(now time.Time, token string, duration time.Duration) (LockDetails, error)
|
|
|
|
// Unlock unlocks the lock with the given token.
|
|
//
|
|
// If Unlock returns ErrForbidden then the Handler will write a "403
|
|
// Forbidden" HTTP Status. If Unlock returns ErrLocked then the Handler
|
|
// will write a "423 Locked" HTTP status. If Unlock returns ErrNoSuchLock
|
|
// then the Handler will write a "409 Conflict" HTTP Status. If it returns
|
|
// any other non-nil error, the Handler will write a "500 Internal Server
|
|
// Error" HTTP status.
|
|
//
|
|
// See http://www.webdav.org/specs/rfc4918.html#rfc.section.9.11.1 for
|
|
// when to use each error.
|
|
Unlock(now time.Time, token string) error
|
|
}
|
|
|
|
// LockDetails are a lock's metadata.
|
|
type LockDetails struct {
|
|
// Root is the root resource name being locked. For a zero-depth lock, the
|
|
// root is the only resource being locked.
|
|
Root string
|
|
// Duration is the lock timeout. A negative duration means infinite.
|
|
Duration time.Duration
|
|
// OwnerXML is the verbatim <owner> XML given in a LOCK HTTP request.
|
|
//
|
|
// TODO: does the "verbatim" nature play well with XML namespaces?
|
|
// Does the OwnerXML field need to have more structure? See
|
|
// https://codereview.appspot.com/175140043/#msg2
|
|
OwnerXML string
|
|
// ZeroDepth is whether the lock has zero depth. If it does not have zero
|
|
// depth, it has infinite depth.
|
|
ZeroDepth bool
|
|
}
|
|
|
|
// NewMemLS returns a new in-memory LockSystem.
|
|
func NewMemLS() LockSystem {
|
|
return &memLS{
|
|
byName: make(map[string]*memLSNode),
|
|
byToken: make(map[string]*memLSNode),
|
|
gen: uint64(time.Now().Unix()),
|
|
}
|
|
}
|
|
|
|
type memLS struct {
|
|
mu sync.Mutex
|
|
byName map[string]*memLSNode
|
|
byToken map[string]*memLSNode
|
|
gen uint64
|
|
// byExpiry only contains those nodes whose LockDetails have a finite
|
|
// Duration and are yet to expire.
|
|
byExpiry byExpiry
|
|
}
|
|
|
|
func (m *memLS) nextToken() string {
|
|
m.gen++
|
|
return strconv.FormatUint(m.gen, 10)
|
|
}
|
|
|
|
func (m *memLS) collectExpiredNodes(now time.Time) {
|
|
for len(m.byExpiry) > 0 {
|
|
if now.Before(m.byExpiry[0].expiry) {
|
|
break
|
|
}
|
|
m.remove(m.byExpiry[0])
|
|
}
|
|
}
|
|
|
|
func (m *memLS) Confirm(now time.Time, name0, name1 string, conditions ...Condition) (func(), error) {
|
|
m.mu.Lock()
|
|
defer m.mu.Unlock()
|
|
m.collectExpiredNodes(now)
|
|
|
|
var n0, n1 *memLSNode
|
|
if name0 != "" {
|
|
if n0 = m.lookup(slashClean(name0), conditions...); n0 == nil {
|
|
return nil, ErrConfirmationFailed
|
|
}
|
|
}
|
|
if name1 != "" {
|
|
if n1 = m.lookup(slashClean(name1), conditions...); n1 == nil {
|
|
return nil, ErrConfirmationFailed
|
|
}
|
|
}
|
|
|
|
// Don't hold the same node twice.
|
|
if n1 == n0 {
|
|
n1 = nil
|
|
}
|
|
|
|
if n0 != nil {
|
|
m.hold(n0)
|
|
}
|
|
if n1 != nil {
|
|
m.hold(n1)
|
|
}
|
|
return func() {
|
|
m.mu.Lock()
|
|
defer m.mu.Unlock()
|
|
if n1 != nil {
|
|
m.unhold(n1)
|
|
}
|
|
if n0 != nil {
|
|
m.unhold(n0)
|
|
}
|
|
}, nil
|
|
}
|
|
|
|
// lookup returns the node n that locks the named resource, provided that n
|
|
// matches at least one of the given conditions and that lock isn't held by
|
|
// another party. Otherwise, it returns nil.
|
|
//
|
|
// n may be a parent of the named resource, if n is an infinite depth lock.
|
|
func (m *memLS) lookup(name string, conditions ...Condition) (n *memLSNode) {
|
|
// TODO: support Condition.Not and Condition.ETag.
|
|
for _, c := range conditions {
|
|
n = m.byToken[c.Token]
|
|
if n == nil || n.held {
|
|
continue
|
|
}
|
|
if name == n.details.Root {
|
|
return n
|
|
}
|
|
if n.details.ZeroDepth {
|
|
continue
|
|
}
|
|
if n.details.Root == "/" || strings.HasPrefix(name, n.details.Root+"/") {
|
|
return n
|
|
}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func (m *memLS) hold(n *memLSNode) {
|
|
if n.held {
|
|
panic("webdav: memLS inconsistent held state")
|
|
}
|
|
n.held = true
|
|
if n.details.Duration >= 0 && n.byExpiryIndex >= 0 {
|
|
heap.Remove(&m.byExpiry, n.byExpiryIndex)
|
|
}
|
|
}
|
|
|
|
func (m *memLS) unhold(n *memLSNode) {
|
|
if !n.held {
|
|
panic("webdav: memLS inconsistent held state")
|
|
}
|
|
n.held = false
|
|
if n.details.Duration >= 0 {
|
|
heap.Push(&m.byExpiry, n)
|
|
}
|
|
}
|
|
|
|
func (m *memLS) Create(now time.Time, details LockDetails) (string, error) {
|
|
m.mu.Lock()
|
|
defer m.mu.Unlock()
|
|
m.collectExpiredNodes(now)
|
|
details.Root = slashClean(details.Root)
|
|
|
|
if !m.canCreate(details.Root, details.ZeroDepth) {
|
|
return "", ErrLocked
|
|
}
|
|
n := m.create(details.Root)
|
|
n.token = m.nextToken()
|
|
m.byToken[n.token] = n
|
|
n.details = details
|
|
if n.details.Duration >= 0 {
|
|
n.expiry = now.Add(n.details.Duration)
|
|
heap.Push(&m.byExpiry, n)
|
|
}
|
|
return n.token, nil
|
|
}
|
|
|
|
func (m *memLS) Refresh(now time.Time, token string, duration time.Duration) (LockDetails, error) {
|
|
m.mu.Lock()
|
|
defer m.mu.Unlock()
|
|
m.collectExpiredNodes(now)
|
|
|
|
n := m.byToken[token]
|
|
if n == nil {
|
|
return LockDetails{}, ErrNoSuchLock
|
|
}
|
|
if n.held {
|
|
return LockDetails{}, ErrLocked
|
|
}
|
|
if n.byExpiryIndex >= 0 {
|
|
heap.Remove(&m.byExpiry, n.byExpiryIndex)
|
|
}
|
|
n.details.Duration = duration
|
|
if n.details.Duration >= 0 {
|
|
n.expiry = now.Add(n.details.Duration)
|
|
heap.Push(&m.byExpiry, n)
|
|
}
|
|
return n.details, nil
|
|
}
|
|
|
|
func (m *memLS) Unlock(now time.Time, token string) error {
|
|
m.mu.Lock()
|
|
defer m.mu.Unlock()
|
|
m.collectExpiredNodes(now)
|
|
|
|
n := m.byToken[token]
|
|
if n == nil {
|
|
return ErrNoSuchLock
|
|
}
|
|
if n.held {
|
|
return ErrLocked
|
|
}
|
|
m.remove(n)
|
|
return nil
|
|
}
|
|
|
|
func (m *memLS) canCreate(name string, zeroDepth bool) bool {
|
|
return walkToRoot(name, func(name0 string, first bool) bool {
|
|
n := m.byName[name0]
|
|
if n == nil {
|
|
return true
|
|
}
|
|
if first {
|
|
if n.token != "" {
|
|
// The target node is already locked.
|
|
return false
|
|
}
|
|
if !zeroDepth {
|
|
// The requested lock depth is infinite, and the fact that n exists
|
|
// (n != nil) means that a descendent of the target node is locked.
|
|
return false
|
|
}
|
|
} else if n.token != "" && !n.details.ZeroDepth {
|
|
// An ancestor of the target node is locked with infinite depth.
|
|
return false
|
|
}
|
|
return true
|
|
})
|
|
}
|
|
|
|
func (m *memLS) create(name string) (ret *memLSNode) {
|
|
walkToRoot(name, func(name0 string, first bool) bool {
|
|
n := m.byName[name0]
|
|
if n == nil {
|
|
n = &memLSNode{
|
|
details: LockDetails{
|
|
Root: name0,
|
|
},
|
|
byExpiryIndex: -1,
|
|
}
|
|
m.byName[name0] = n
|
|
}
|
|
n.refCount++
|
|
if first {
|
|
ret = n
|
|
}
|
|
return true
|
|
})
|
|
return ret
|
|
}
|
|
|
|
func (m *memLS) remove(n *memLSNode) {
|
|
delete(m.byToken, n.token)
|
|
n.token = ""
|
|
walkToRoot(n.details.Root, func(name0 string, first bool) bool {
|
|
x := m.byName[name0]
|
|
x.refCount--
|
|
if x.refCount == 0 {
|
|
delete(m.byName, name0)
|
|
}
|
|
return true
|
|
})
|
|
if n.byExpiryIndex >= 0 {
|
|
heap.Remove(&m.byExpiry, n.byExpiryIndex)
|
|
}
|
|
}
|
|
|
|
func walkToRoot(name string, f func(name0 string, first bool) bool) bool {
|
|
for first := true; ; first = false {
|
|
if !f(name, first) {
|
|
return false
|
|
}
|
|
if name == "/" {
|
|
break
|
|
}
|
|
name = name[:strings.LastIndex(name, "/")]
|
|
if name == "" {
|
|
name = "/"
|
|
}
|
|
}
|
|
return true
|
|
}
|
|
|
|
type memLSNode struct {
|
|
// details are the lock metadata. Even if this node's name is not explicitly locked,
|
|
// details.Root will still equal the node's name.
|
|
details LockDetails
|
|
// token is the unique identifier for this node's lock. An empty token means that
|
|
// this node is not explicitly locked.
|
|
token string
|
|
// refCount is the number of self-or-descendent nodes that are explicitly locked.
|
|
refCount int
|
|
// expiry is when this node's lock expires.
|
|
expiry time.Time
|
|
// byExpiryIndex is the index of this node in memLS.byExpiry. It is -1
|
|
// if this node does not expire, or has expired.
|
|
byExpiryIndex int
|
|
// held is whether this node's lock is actively held by a Confirm call.
|
|
held bool
|
|
}
|
|
|
|
type byExpiry []*memLSNode
|
|
|
|
func (b *byExpiry) Len() int {
|
|
return len(*b)
|
|
}
|
|
|
|
func (b *byExpiry) Less(i, j int) bool {
|
|
return (*b)[i].expiry.Before((*b)[j].expiry)
|
|
}
|
|
|
|
func (b *byExpiry) Swap(i, j int) {
|
|
(*b)[i], (*b)[j] = (*b)[j], (*b)[i]
|
|
(*b)[i].byExpiryIndex = i
|
|
(*b)[j].byExpiryIndex = j
|
|
}
|
|
|
|
func (b *byExpiry) Push(x interface{}) {
|
|
n := x.(*memLSNode)
|
|
n.byExpiryIndex = len(*b)
|
|
*b = append(*b, n)
|
|
}
|
|
|
|
func (b *byExpiry) Pop() interface{} {
|
|
i := len(*b) - 1
|
|
n := (*b)[i]
|
|
(*b)[i] = nil
|
|
n.byExpiryIndex = -1
|
|
*b = (*b)[:i]
|
|
return n
|
|
}
|
|
|
|
const infiniteTimeout = -1
|
|
|
|
// parseTimeout parses the Timeout HTTP header, as per section 10.7. If s is
|
|
// empty, an infiniteTimeout is returned.
|
|
func parseTimeout(s string) (time.Duration, error) {
|
|
if s == "" {
|
|
return infiniteTimeout, nil
|
|
}
|
|
if i := strings.IndexByte(s, ','); i >= 0 {
|
|
s = s[:i]
|
|
}
|
|
s = strings.TrimSpace(s)
|
|
if s == "Infinite" {
|
|
return infiniteTimeout, nil
|
|
}
|
|
const pre = "Second-"
|
|
if !strings.HasPrefix(s, pre) {
|
|
return 0, errInvalidTimeout
|
|
}
|
|
s = s[len(pre):]
|
|
if s == "" || s[0] < '0' || '9' < s[0] {
|
|
return 0, errInvalidTimeout
|
|
}
|
|
n, err := strconv.ParseInt(s, 10, 64)
|
|
if err != nil || 1<<32-1 < n {
|
|
return 0, errInvalidTimeout
|
|
}
|
|
return time.Duration(n) * time.Second, nil
|
|
}
|