133 lines
3.9 KiB
Go
133 lines
3.9 KiB
Go
// Copyright 2018 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 dirhash defines hashes over directory trees.
|
|
// These hashes are recorded in go.sum files and in the Go checksum database,
|
|
// to allow verifying that a newly-downloaded module has the expected content.
|
|
package dirhash
|
|
|
|
import (
|
|
"archive/zip"
|
|
"crypto/sha256"
|
|
"encoding/base64"
|
|
"errors"
|
|
"fmt"
|
|
"io"
|
|
"os"
|
|
"path/filepath"
|
|
"sort"
|
|
"strings"
|
|
)
|
|
|
|
// DefaultHash is the default hash function used in new go.sum entries.
|
|
var DefaultHash Hash = Hash1
|
|
|
|
// A Hash is a directory hash function.
|
|
// It accepts a list of files along with a function that opens the content of each file.
|
|
// It opens, reads, hashes, and closes each file and returns the overall directory hash.
|
|
type Hash func(files []string, open func(string) (io.ReadCloser, error)) (string, error)
|
|
|
|
// Hash1 is the "h1:" directory hash function, using SHA-256.
|
|
//
|
|
// Hash1 is "h1:" followed by the base64-encoded SHA-256 hash of a summary
|
|
// prepared as if by the Unix command:
|
|
//
|
|
// find . -type f | sort | sha256sum
|
|
//
|
|
// More precisely, the hashed summary contains a single line for each file in the list,
|
|
// ordered by sort.Strings applied to the file names, where each line consists of
|
|
// the hexadecimal SHA-256 hash of the file content,
|
|
// two spaces (U+0020), the file name, and a newline (U+000A).
|
|
//
|
|
// File names with newlines (U+000A) are disallowed.
|
|
func Hash1(files []string, open func(string) (io.ReadCloser, error)) (string, error) {
|
|
h := sha256.New()
|
|
files = append([]string(nil), files...)
|
|
sort.Strings(files)
|
|
for _, file := range files {
|
|
if strings.Contains(file, "\n") {
|
|
return "", errors.New("dirhash: filenames with newlines are not supported")
|
|
}
|
|
r, err := open(file)
|
|
if err != nil {
|
|
return "", err
|
|
}
|
|
hf := sha256.New()
|
|
_, err = io.Copy(hf, r)
|
|
r.Close()
|
|
if err != nil {
|
|
return "", err
|
|
}
|
|
fmt.Fprintf(h, "%x %s\n", hf.Sum(nil), file)
|
|
}
|
|
return "h1:" + base64.StdEncoding.EncodeToString(h.Sum(nil)), nil
|
|
}
|
|
|
|
// HashDir returns the hash of the local file system directory dir,
|
|
// replacing the directory name itself with prefix in the file names
|
|
// used in the hash function.
|
|
func HashDir(dir, prefix string, hash Hash) (string, error) {
|
|
files, err := DirFiles(dir, prefix)
|
|
if err != nil {
|
|
return "", err
|
|
}
|
|
osOpen := func(name string) (io.ReadCloser, error) {
|
|
return os.Open(filepath.Join(dir, strings.TrimPrefix(name, prefix)))
|
|
}
|
|
return hash(files, osOpen)
|
|
}
|
|
|
|
// DirFiles returns the list of files in the tree rooted at dir,
|
|
// replacing the directory name dir with prefix in each name.
|
|
// The resulting names always use forward slashes.
|
|
func DirFiles(dir, prefix string) ([]string, error) {
|
|
var files []string
|
|
dir = filepath.Clean(dir)
|
|
err := filepath.Walk(dir, func(file string, info os.FileInfo, err error) error {
|
|
if err != nil {
|
|
return err
|
|
}
|
|
if info.IsDir() {
|
|
return nil
|
|
}
|
|
rel := file
|
|
if dir != "." {
|
|
rel = file[len(dir)+1:]
|
|
}
|
|
f := filepath.Join(prefix, rel)
|
|
files = append(files, filepath.ToSlash(f))
|
|
return nil
|
|
})
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return files, nil
|
|
}
|
|
|
|
// HashZip returns the hash of the file content in the named zip file.
|
|
// Only the file names and their contents are included in the hash:
|
|
// the exact zip file format encoding, compression method,
|
|
// per-file modification times, and other metadata are ignored.
|
|
func HashZip(zipfile string, hash Hash) (string, error) {
|
|
z, err := zip.OpenReader(zipfile)
|
|
if err != nil {
|
|
return "", err
|
|
}
|
|
defer z.Close()
|
|
var files []string
|
|
zfiles := make(map[string]*zip.File)
|
|
for _, file := range z.File {
|
|
files = append(files, file.Name)
|
|
zfiles[file.Name] = file
|
|
}
|
|
zipOpen := func(name string) (io.ReadCloser, error) {
|
|
f := zfiles[name]
|
|
if f == nil {
|
|
return nil, fmt.Errorf("file %q not found in zip", name) // should never happen
|
|
}
|
|
return f.Open()
|
|
}
|
|
return hash(files, zipOpen)
|
|
}
|