1package smtpserver

2

3import (

4 "bytes"

5 "context"

6 "crypto/sha256"

7 "fmt"

8 "io"

9 "log/slog"

10 "os"

11

12 "github.com/mjl-/bstore"

13

14 "github.com/mjl-/mox/message"

15 "github.com/mjl-/mox/mlog"

16 "github.com/mjl-/mox/moxio"

17 "github.com/mjl-/mox/store"

18)

19

20// rejectPresent returns whether the message is already present in the rejects mailbox.

21func rejectPresent(log mlog.Log, acc *store.Account, rejectsMailbox string, m *store.Message, f *os.File) (present bool, msgID string, hash []byte, rerr error) {

22 if p, err := message.Parse(log.Logger, false, store.FileMsgReader(m.MsgPrefix, f)); err != nil {

23 log.Infox("parsing reject message for message-id", err)

24 } else if header, err := p.Header(); err != nil {

25 log.Infox("parsing reject message header for message-id", err)

26 } else {

27 msgID, _, err = message.MessageIDCanonical(header.Get("Message-Id"))

28 if err != nil {

29 log.Debugx("parsing message-id for reject", err, slog.String("messageid", header.Get("Message-Id")))

30 }

31 }

32

33 // We must not read MsgPrefix, it will likely change for subsequent deliveries.

34 h := sha256.New()

35 if _, err := io.Copy(h, &moxio.AtReader{R: f}); err != nil {

36 log.Infox("copying reject message to hash", err)

37 } else {

38 hash = h.Sum(nil)

39 }

40

41 if msgID == "" && len(hash) == 0 {

42 return false, "", nil, fmt.Errorf("no message-id or hash for determining reject message presence")

43 }

44

45 var exists bool

46 var err error

47 acc.WithRLock(func() {

48 err = acc.DB.Read(context.TODO(), func(tx *bstore.Tx) error {

49 mbq := bstore.QueryTx[store.Mailbox](tx)

50 mbq.FilterNonzero(store.Mailbox{Name: rejectsMailbox})

51 mb, err := mbq.Get()

52 if err == bstore.ErrAbsent {

53 return nil

54 }

55 if err != nil {

56 return fmt.Errorf("looking for rejects mailbox: %w", err)

57 }

58

59 q := bstore.QueryTx[store.Message](tx)

60 q.FilterNonzero(store.Message{MailboxID: mb.ID})

61 q.FilterEqual("Expunged", false)

62 q.FilterFn(func(m store.Message) bool {

63 return msgID != "" && m.MessageID == msgID || len(hash) > 0 && bytes.Equal(m.MessageHash, hash)

64 })

65 exists, err = q.Exists()

66 return err

67 })

68 })

69 if err != nil {

70 return false, "", nil, fmt.Errorf("querying for presence of reject message: %w", err)

71 }

72 return exists, msgID, hash, nil

73}

74