130 lines
3.3 KiB
Go
130 lines
3.3 KiB
Go
// Copyright 2016 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package autocert
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import (
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"errors"
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"io/ioutil"
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"os"
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"path/filepath"
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"golang.org/x/net/context"
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)
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// ErrCacheMiss is returned when a certificate is not found in cache.
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var ErrCacheMiss = errors.New("acme/autocert: certificate cache miss")
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// Cache is used by Manager to store and retrieve previously obtained certificates
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// as opaque data.
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//
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// The key argument of the methods refers to a domain name but need not be an FQDN.
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// Cache implementations should not rely on the key naming pattern.
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type Cache interface {
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// Get returns a certificate data for the specified key.
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// If there's no such key, Get returns ErrCacheMiss.
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Get(ctx context.Context, key string) ([]byte, error)
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// Put stores the data in the cache under the specified key.
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// Underlying implementations may use any data storage format,
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// as long as the reverse operation, Get, results in the original data.
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Put(ctx context.Context, key string, data []byte) error
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// Delete removes a certificate data from the cache under the specified key.
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// If there's no such key in the cache, Delete returns nil.
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Delete(ctx context.Context, key string) error
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}
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// DirCache implements Cache using a directory on the local filesystem.
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// If the directory does not exist, it will be created with 0700 permissions.
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type DirCache string
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// Get reads a certificate data from the specified file name.
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func (d DirCache) Get(ctx context.Context, name string) ([]byte, error) {
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name = filepath.Join(string(d), name)
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var (
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data []byte
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err error
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done = make(chan struct{})
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)
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go func() {
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data, err = ioutil.ReadFile(name)
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close(done)
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}()
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select {
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case <-ctx.Done():
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return nil, ctx.Err()
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case <-done:
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}
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if os.IsNotExist(err) {
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return nil, ErrCacheMiss
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}
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return data, err
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}
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// Put writes the certificate data to the specified file name.
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// The file will be created with 0600 permissions.
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func (d DirCache) Put(ctx context.Context, name string, data []byte) error {
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if err := os.MkdirAll(string(d), 0700); err != nil {
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return err
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}
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done := make(chan struct{})
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var err error
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go func() {
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defer close(done)
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var tmp string
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if tmp, err = d.writeTempFile(name, data); err != nil {
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return
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}
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// prevent overwriting the file if the context was cancelled
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if ctx.Err() != nil {
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return // no need to set err
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}
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name = filepath.Join(string(d), name)
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err = os.Rename(tmp, name)
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}()
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select {
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case <-ctx.Done():
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return ctx.Err()
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case <-done:
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}
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return err
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}
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// Delete removes the specified file name.
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func (d DirCache) Delete(ctx context.Context, name string) error {
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name = filepath.Join(string(d), name)
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var (
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err error
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done = make(chan struct{})
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)
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go func() {
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err = os.Remove(name)
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close(done)
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}()
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select {
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case <-ctx.Done():
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return ctx.Err()
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case <-done:
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}
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if err != nil && !os.IsNotExist(err) {
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return err
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}
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return nil
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}
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// writeTempFile writes b to a temporary file, closes the file and returns its path.
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func (d DirCache) writeTempFile(prefix string, b []byte) (string, error) {
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// TempFile uses 0600 permissions
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f, err := ioutil.TempFile(string(d), prefix)
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if err != nil {
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return "", err
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}
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if _, err := f.Write(b); err != nil {
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f.Close()
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return "", err
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}
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return f.Name(), f.Close()
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}
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