main.go

   1 /*
   2 uploader -- simplest form file uploader
   3 Copyright (C) 2018-2022 Sergey Matveev <stargrave@stargrave.org>
   4
   5 This program is free software: you can redistribute it and/or modify
   6 it under the terms of the GNU General Public License as published by
   7 the Free Software Foundation, version 3 of the License.
   8
   9 This program is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 GNU General Public License for more details.
  13
  14 You should have received a copy of the GNU General Public License
  15 along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16 */
  17
  18 package main
  19
  20 import (
  21         "bufio"
  22         "bytes"
  23         "encoding/base64"
  24         "encoding/hex"
  25         "flag"
  26         "fmt"
  27         "html/template"
  28         "io"
  29         "io/ioutil"
  30         "log"
  31         "mime"
  32         "net"
  33         "net/http"
  34         "os"
  35         "os/exec"
  36         "strconv"
  37         "strings"
  38         "sync"
  39         "time"
  40
  41         "go.cypherpunks.ru/recfile"
  42         "go.cypherpunks.ru/tai64n/v2"
  43         "golang.org/x/crypto/blake2b"
  44         "golang.org/x/net/netutil"
  45 )
  46
  47 const (
  48         WriteBufSize     = 1 << 20
  49         FileFieldName    = "file"
  50         CommentFieldName = "comment"
  51
  52         SendmailCmd = "/usr/sbin/sendmail"
  53 )
  54
  55 var (
  56         Index = template.Must(template.New("index").Parse(`<html>
  57 <head><title>Upload</title></head><body>
  58 Example command line usage:
  59 <pre>
  60 $ curl -F file=@somedata.tar.gpg [-F comment="optional comment"] http://.../upload/
  61 $ b2sum somedata.tar.gpg # to verify BLAKE2b-512 checksum
  62 </pre>
  63 <form enctype="multipart/form-data" action="/upload/" method="post">
  64 <label for="file">File to upload:</label><br/>
  65 <input name="file" type="file" name="{{.}}" /><br/>
  66 <label for="comment">Optional comment:</label></br>
  67 <textarea name="comment" cols="80" rows="25" name="comment"></textarea><br/>
  68 <input type="submit" />
  69 </form></body></html>`))
  70         NotifyFromAddr *string
  71         NotifyToAddr   *string
  72         Jobs           sync.WaitGroup
  73 )
  74
  75 func upload(w http.ResponseWriter, r *http.Request) {
  76         log.Println(r.RemoteAddr, "connected")
  77         if r.Method == http.MethodGet {
  78                 if err := Index.Execute(w, FileFieldName); err != nil {
  79                         log.Println(r.RemoteAddr, err)
  80                 }
  81                 return
  82         }
  83         mr, err := r.MultipartReader()
  84         if err != nil {
  85                 log.Println(r.RemoteAddr, err)
  86                 return
  87         }
  88         p, err := mr.NextPart()
  89         if err != nil {
  90                 log.Println(r.RemoteAddr, err)
  91                 return
  92         }
  93         if p.FormName() != FileFieldName {
  94                 log.Println(r.RemoteAddr, "non file form field")
  95                 return
  96         }
  97         h, err := blake2b.New512(nil)
  98         if err != nil {
  99                 panic(err)
 100         }
 101         t := time.Now()
 102         ts := new(tai64n.TAI64N)
 103         ts.FromTime(t)
 104         tai := tai64n.Encode(ts[:])[1:]
 105         fnOrig := p.FileName()
 106         fd, err := os.OpenFile(tai+".part", os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0666)
 107         if err != nil {
 108                 log.Println(r.RemoteAddr, tai, fnOrig, err)
 109                 return
 110         }
 111         fdBuf := bufio.NewWriterSize(fd, WriteBufSize)
 112         mw := io.MultiWriter(fdBuf, h)
 113         n, err := io.Copy(mw, p)
 114         if err != nil {
 115                 log.Println(r.RemoteAddr, tai, fnOrig, err)
 116                 fd.Close()
 117                 return
 118         }
 119         if n == 0 {
 120                 log.Println(r.RemoteAddr, tai, fnOrig, "empty")
 121                 os.Remove(tai + ".part")
 122                 fd.Close()
 123                 fmt.Fprintf(w, "Empty file")
 124                 return
 125         }
 126         if err = fdBuf.Flush(); err != nil {
 127                 log.Println(r.RemoteAddr, tai, fnOrig, err)
 128                 fd.Close()
 129                 return
 130         }
 131         if err = fd.Sync(); err != nil {
 132                 log.Println(r.RemoteAddr, tai, fnOrig, err)
 133                 fd.Close()
 134                 return
 135         }
 136         fd.Close()
 137         sum := hex.EncodeToString(h.Sum(nil))
 138         if err = os.Rename(tai+".part", tai); err != nil {
 139                 log.Println(r.RemoteAddr, tai, fnOrig, n, sum, err)
 140                 return
 141         }
 142
 143         var rec bytes.Buffer
 144         wr := recfile.NewWriter(&rec)
 145         if _, err = wr.WriteFields(
 146                 recfile.Field{Name: "TAI64N", Value: tai},
 147                 recfile.Field{Name: "Size", Value: strconv.FormatInt(n, 10)},
 148                 recfile.Field{Name: "Checksum", Value: sum},
 149         ); err != nil {
 150                 log.Println(r.RemoteAddr, tai, fnOrig, n, sum, err)
 151                 return
 152         }
 153         if _, err = w.Write(rec.Bytes()); err == nil {
 154                 log.Println(r.RemoteAddr, tai, fnOrig, n, sum)
 155         } else {
 156                 log.Println(r.RemoteAddr, tai, fnOrig, n, sum, err)
 157                 return
 158         }
 159
 160         if _, err = wr.WriteFields(
 161                 recfile.Field{Name: "Filename", Value: fnOrig},
 162         ); err != nil {
 163                 log.Println(r.RemoteAddr, tai, fnOrig, n, sum, err)
 164                 return
 165         }
 166
 167         var commentLines []string
 168         p, err = mr.NextPart()
 169         if err == nil && p.FormName() == CommentFieldName {
 170                 comment, err := ioutil.ReadAll(p)
 171                 if err == nil && len(comment) > 0 {
 172                         commentLines = strings.Split(string(comment), "\n")
 173                         wr.WriteFieldMultiline("Comment", commentLines)
 174                 }
 175         }
 176
 177         ioutil.WriteFile(tai+".rec", rec.Bytes(), os.FileMode(0666))
 178         if *NotifyToAddr == "" {
 179                 return
 180         }
 181         cmd := exec.Command(SendmailCmd, *NotifyToAddr)
 182         cmd.Stdin = io.MultiReader(
 183                 strings.NewReader(fmt.Sprintf(
 184                         `From: %s
 185 To: %s
 186 Subject: %s
 187 MIME-Version: 1.0
 188 Content-Type: text/plain; charset=utf-8
 189 Content-Transfer-Encoding: base64
 190
 191 `,
 192                         *NotifyFromAddr,
 193                         *NotifyToAddr,
 194                         mime.BEncoding.Encode("UTF-8", fmt.Sprintf("%s (%d KiB)", fnOrig, n/1024)),
 195                 )),
 196                 strings.NewReader(base64.StdEncoding.EncodeToString(rec.Bytes())),
 197         )
 198         Jobs.Add(1)
 199         go func() {
 200                 cmd.Run()
 201                 Jobs.Done()
 202         }()
 203 }
 204
 205 func main() {
 206         doUCSPI := flag.Bool("ucspi", false, "Work as UCSPI-TCP service")
 207         bind := flag.String("bind", "[::]:8086", "Address to bind to")
 208         conns := flag.Int("conns", 2, "Maximal number of connections")
 209         NotifyFromAddr = flag.String("notify-from", "uploader@example.com", "Address notifications are sent to")
 210         NotifyToAddr = flag.String("notify-to", "", "Address notifications are sent from")
 211         flag.Parse()
 212         log.SetFlags(log.Lshortfile)
 213         if !*doUCSPI {
 214                 log.SetOutput(os.Stdout)
 215         }
 216         if len(*NotifyFromAddr) == 0 && len(*NotifyToAddr) > 0 {
 217                 log.Fatalln("notify-from address can not be empty, if notify-to is set")
 218         }
 219         s := &http.Server{
 220                 ReadHeaderTimeout: 10 * time.Second,
 221                 MaxHeaderBytes:    10 * (1 << 10),
 222         }
 223         http.HandleFunc("/upload/", upload)
 224         if *doUCSPI {
 225                 s.SetKeepAlivesEnabled(false)
 226                 ln := &UCSPI{}
 227                 s.ConnState = connStater
 228                 err := s.Serve(ln)
 229                 if _, ok := err.(UCSPIAlreadyAccepted); !ok {
 230                         log.Fatalln(err)
 231                 }
 232                 Jobs.Wait()
 233         } else {
 234                 ln, err := net.Listen("tcp", *bind)
 235                 if err != nil {
 236                         log.Fatalln(err)
 237                 }
 238                 log.Println("listening", *bind)
 239                 ln = netutil.LimitListener(ln, *conns)
 240                 if err = s.Serve(ln); err != nil {
 241                         log.Fatalln(err)
 242                 }
 243         }
 244 }