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// Copyright 2015 CoreOS, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package util
import (
"bufio"
"compress/gzip"
"encoding/hex"
"hash"
"io"
"io/ioutil"
"net/url"
"os"
"path/filepath"
"github.com/coreos/ignition/config/types"
"github.com/coreos/ignition/internal/log"
"github.com/coreos/ignition/internal/resource"
"golang.org/x/net/context"
)
const (
DefaultDirectoryPermissions os.FileMode = 0755
DefaultFilePermissions os.FileMode = 0644
)
type File struct {
io.ReadCloser
hash.Hash
Path string
Mode os.FileMode
Uid int
Gid int
expectedSum string
}
func (f File) Verify() error {
if f.Hash == nil {
return nil
}
sum := f.Sum(nil)
encodedSum := make([]byte, hex.EncodedLen(len(sum)))
hex.Encode(encodedSum, sum)
if string(encodedSum) != f.expectedSum {
return ErrHashMismatch{
Calculated: string(encodedSum),
Expected: f.expectedSum,
}
}
return nil
}
// newHashedReader returns a new ReadCloser that also writes to the provided hash.
func newHashedReader(reader io.ReadCloser, hasher hash.Hash) io.ReadCloser {
return struct {
io.Reader
io.Closer
}{
Reader: io.TeeReader(reader, hasher),
Closer: reader,
}
}
// RenderFile returns a *File with a Reader that downloads, hashes, and decompresses the incoming data.
// It returns nil if f had invalid options. Errors reading/verifying/decompressing the file will
// present themselves when the Reader is actually read from.
func RenderFile(l *log.Logger, c *resource.HttpClient, f types.File) *File {
var reader io.ReadCloser
var err error
var expectedSum string
// explicitly ignoring the error here because the config should already be
// validated by this point
u, _ := url.Parse(f.Contents.Source)
reader, err = resource.FetchAsReader(l, c, context.Background(), *u)
if err != nil {
l.Crit("Error fetching file %q: %v", f.Path, err)
return nil
}
fileHash, err := GetHasher(f.Contents.Verification)
if err != nil {
l.Crit("Error verifying file %q: %v", f.Path, err)
return nil
}
if fileHash != nil {
reader = newHashedReader(reader, fileHash)
// explicitly ignoring the error here because the config should already
// be validated by this point
_, expectedSum, _ = f.Contents.Verification.HashParts()
}
reader, err = decompressFileStream(l, f, reader)
if err != nil {
l.Crit("Error decompressing file %q: %v", f.Path, err)
return nil
}
return &File{
Path: f.Path,
ReadCloser: reader,
Hash: fileHash,
Mode: os.FileMode(f.Mode),
Uid: f.User.ID,
Gid: f.Group.ID,
expectedSum: expectedSum,
}
}
// gzipReader is a wrapper for gzip's reader that closes the stream it wraps as well
// as itself when Close() is called.
type gzipReader struct {
*gzip.Reader //actually a ReadCloser
source io.Closer
}
func newGzipReader(reader io.ReadCloser) (io.ReadCloser, error) {
gzReader, err := gzip.NewReader(reader)
if err != nil {
return nil, err
}
return gzipReader{
Reader: gzReader,
source: reader,
}, nil
}
func (gz gzipReader) Close() error {
if err := gz.Reader.Close(); err != nil {
return err
}
if err := gz.source.Close(); err != nil {
return err
}
return nil
}
func decompressFileStream(l *log.Logger, f types.File, contents io.ReadCloser) (io.ReadCloser, error) {
switch f.Contents.Compression {
case "":
return contents, nil
case "gzip":
return newGzipReader(contents)
default:
return nil, types.ErrCompressionInvalid
}
}
func (u Util) WriteLink(s types.Link) error {
path := u.JoinPath(s.Path)
if err := MkdirForFile(path); err != nil {
return err
}
if s.Hard {
return os.Link(s.Target, path)
}
return os.Symlink(s.Target, path)
}
// WriteFile creates and writes the file described by f using the provided context.
func (u Util) WriteFile(f *File) error {
defer f.Close()
var err error
path := u.JoinPath(string(f.Path))
if err := MkdirForFile(path); err != nil {
return err
}
// Create a temporary file in the same directory to ensure it's on the same filesystem
var tmp *os.File
if tmp, err = ioutil.TempFile(filepath.Dir(path), "tmp"); err != nil {
return err
}
defer func() {
tmp.Close()
if err != nil {
os.Remove(tmp.Name())
}
}()
fileWriter := bufio.NewWriter(tmp)
if _, err = io.Copy(fileWriter, f); err != nil {
return err
}
fileWriter.Flush()
if err = f.Verify(); err != nil {
return err
}
// XXX(vc): Note that we assume to be operating on the file we just wrote, this is only guaranteed
// by using syscall.Fchown() and syscall.Fchmod()
// Ensure the ownership and mode are as requested (since WriteFile can be affected by sticky bit)
if err = os.Chown(tmp.Name(), f.Uid, f.Gid); err != nil {
return err
}
if err = os.Chmod(tmp.Name(), f.Mode); err != nil {
return err
}
if err = os.Rename(tmp.Name(), path); err != nil {
return err
}
return nil
}
// MkdirForFile helper creates the directory components of path.
func MkdirForFile(path string) error {
return os.MkdirAll(filepath.Dir(path), DefaultDirectoryPermissions)
}
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