cmd/meta4-check/main.go

   1 // meta4ra -- Metalink 4.0 utilities
   2 // Copyright (C) 2021-2024 Sergey Matveev <stargrave@stargrave.org>
   3 //
   4 // This program is free software: you can redistribute it and/or modify
   5 // it under the terms of the GNU General Public License as published by
   6 // the Free Software Foundation, version 3 of the License.
   7 //
   8 // This program is distributed in the hope that it will be useful,
   9 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 // GNU General Public License for more details.
  12 //
  13 // You should have received a copy of the GNU General Public License
  14 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15
  16 // Metalink 4.0 checker
  17 package main
  18
  19 import (
  20         "bufio"
  21         "encoding/xml"
  22         "flag"
  23         "fmt"
  24         "io"
  25         "io/fs"
  26         "log"
  27         "os"
  28         "path"
  29         "strings"
  30
  31         "go.stargrave.org/meta4ra"
  32 )
  33
  34 func main() {
  35         hashes := flag.String("hashes",
  36                 strings.Join(meta4ra.HashesDefault, ","), "hash-name:command-s")
  37         extractSig := flag.Bool("extract-sig", false, "Extract signature files")
  38         metaPath := flag.String("meta4", "file.meta4", "Metalink file")
  39         flag.Usage = func() {
  40                 fmt.Fprintf(flag.CommandLine.Output(),
  41                         "Usage: %s [options] [FILE ...]\n", os.Args[0])
  42                 flag.PrintDefaults()
  43                 fmt.Fprint(flag.CommandLine.Output(), `
  44 If no FILEs are specified, then all <file>s from metalink are searched and
  45 verified if they exist. Otherwise only specified FILEs are checked. If you
  46 want to skip any <file> verification (for example only to validate the format
  47 and -extract-sig, then you can just specify empty ("") FILE.
  48 `)
  49         }
  50         flag.Parse()
  51         log.SetFlags(log.Lshortfile)
  52
  53         data, err := os.ReadFile(*metaPath)
  54         if err != nil {
  55                 log.Fatalln(err)
  56         }
  57         var meta meta4ra.Metalink
  58         err = xml.Unmarshal(data, &meta)
  59         if err != nil {
  60                 log.Fatalln(err)
  61         }
  62
  63         toCheck := make(map[string]string)
  64         for _, fn := range flag.Args() {
  65                 toCheck[path.Base(fn)] = fn
  66         }
  67
  68         bad := false
  69         for _, f := range meta.Files {
  70                 for _, sig := range f.Signature {
  71                         if !*extractSig {
  72                                 continue
  73                         }
  74                         var fn string
  75                         switch sig.MediaType {
  76                         case meta4ra.SigMediaTypePGP:
  77                                 fn = f.Name + ".asc"
  78                         case meta4ra.SigMediaTypeSSH:
  79                                 fn = f.Name + ".sig"
  80                         }
  81                         if fn == "" {
  82                                 continue
  83                         }
  84                         if err = os.WriteFile(
  85                                 fn,
  86                                 []byte(strings.TrimPrefix(sig.Signature, "\n")),
  87                                 fs.FileMode(0666),
  88                         ); err != nil {
  89                                 fmt.Println("Error:", f.Name, "can not save signature:", err)
  90                                 bad = true
  91                         }
  92                 }
  93
  94                 fullPath := toCheck[f.Name]
  95                 if !(len(toCheck) == 0 || fullPath != "") {
  96                         continue
  97                 }
  98                 if fullPath == "" {
  99                         fullPath = f.Name
 100                 }
 101                 s, err := os.Stat(fullPath)
 102                 if err != nil {
 103                         fmt.Println(err)
 104                         bad = true
 105                         continue
 106                 }
 107                 if uint64(s.Size()) != f.Size {
 108                         fmt.Println("size mismatch",
 109                                 f.Name, "our:", s.Size(), "their:", f.Size)
 110                         bad = true
 111                         continue
 112                 }
 113
 114                 hasher := meta4ra.NewHasher(*hashes)
 115                 var hashTheir string
 116                 var hashName string
 117                 for i, name := range hasher.Names {
 118                         for _, h := range f.Hashes {
 119                                 if h.Type == name {
 120                                         hasher.Names = []string{name}
 121                                         hasher.Cmds = append(hasher.Cmds[:0], hasher.Cmds[i])
 122                                         hasher.Ins = append(hasher.Ins[:0], hasher.Ins[i])
 123                                         hasher.Outs = append(hasher.Outs[:0], hasher.Outs[i])
 124                                         hashName = name
 125                                         hashTheir = h.Hash
 126                                         goto HashFound
 127                                 }
 128                         }
 129                 }
 130                 fmt.Println("no common hashes found for:", f.Name)
 131                 bad = true
 132                 continue
 133
 134         HashFound:
 135                 fd, err := os.Open(fullPath)
 136                 if err != nil {
 137                         fmt.Println("Error:", f.Name, err)
 138                         bad = true
 139                         continue
 140                 }
 141                 hasher.Start()
 142                 _, err = io.Copy(hasher, bufio.NewReaderSize(fd, 1<<20))
 143                 fd.Close()
 144                 sums := hasher.Sums()
 145                 if err != nil {
 146                         fmt.Println("Error:", f.Name, err)
 147                         bad = true
 148                         continue
 149                 }
 150                 hashOur := sums[0].Hash
 151                 if hashOur == hashTheir {
 152                         fmt.Println(f.Name, hashName, "good")
 153                 } else {
 154                         fmt.Println(
 155                                 "hash mismatch:", f.Name, hashName,
 156                                 "our:", hashOur,
 157                                 "their:", hashTheir,
 158                         )
 159                         bad = true
 160                         continue
 161                 }
 162         }
 163         if bad {
 164                 os.Exit(1)
 165         }
 166 }