--- /dev/null
+/*
+meta4a -- Metalink 4.0 checker
+Copyright (C) 2021 Sergey Matveev <stargrave@stargrave.org>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, version 3 of the License.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+// Metalink 4.0 checker
+package main
+
+import (
+ "bufio"
+ "crypto/sha256"
+ "crypto/sha512"
+ "encoding/hex"
+ "encoding/xml"
+ "flag"
+ "fmt"
+ "hash"
+ "io"
+ "io/fs"
+ "io/ioutil"
+ "log"
+ "os"
+
+ "go.stargrave.org/meta4ra"
+)
+
+func main() {
+ extractSig := flag.Bool("extract-sig", false, "Extract signature files")
+ log.SetFlags(log.Lshortfile)
+ flag.Parse()
+ sha256Hasher := sha256.New()
+ sha512Hasher := sha512.New()
+ bad := false
+ for _, metaPath := range flag.Args() {
+ data, err := ioutil.ReadFile(metaPath)
+ if err != nil {
+ log.Fatalln(err)
+ }
+ var meta meta4ra.Metalink
+ err = xml.Unmarshal(data, &meta)
+ if err != nil {
+ log.Fatalln(err)
+ }
+ for _, f := range meta.Files {
+ if f.Signature != nil && *extractSig {
+ if err = ioutil.WriteFile(
+ f.Name+".asc",
+ []byte(f.Signature.Signature),
+ fs.FileMode(0666),
+ ); err != nil {
+ fmt.Println("Error:", f.Name, "can not save signature:", err)
+ bad = true
+ }
+ }
+ var sha256Digest string
+ var sha512Digest string
+ fd, err := os.Open(f.Name)
+ if err != nil {
+ continue
+ }
+ for _, h := range f.Hashes {
+ switch h.Type {
+ case meta4ra.HashSHA256:
+ sha256Digest = h.Hash
+ case meta4ra.HashSHA512:
+ sha512Digest = h.Hash
+ }
+ }
+ var digestTheir string
+ var digestName string
+ var hasher hash.Hash
+ if sha512Digest != "" {
+ digestName = meta4ra.HashSHA512
+ digestTheir = sha512Digest
+ hasher = sha512Hasher
+ } else if sha256Digest != "" {
+ digestName = meta4ra.HashSHA256
+ digestTheir = sha256Digest
+ hasher = sha256Hasher
+ } else {
+ fd.Close()
+ fmt.Println("Error:", f.Name, "no satisfiable hash algorithm found")
+ bad = true
+ continue
+ }
+ hasher.Reset()
+ _, err = io.Copy(hasher, bufio.NewReader(fd))
+ fd.Close()
+ if err != nil {
+ fmt.Println("Error:", f.Name, err)
+ bad = true
+ continue
+ }
+ digestOur := hex.EncodeToString(hasher.Sum(nil))
+ if digestOur == digestTheir {
+ fmt.Println(f.Name, digestName, "good")
+ } else {
+ fmt.Println(
+ "Hash does not match:", f.Name, digestName,
+ "our:", digestOur,
+ "their:", digestTheir,
+ )
+ bad = true
+ continue
+ }
+ }
+ }
+ if bad {
+ os.Exit(1)
+ }
+}