Allow specifying NON-PRINT format control

[siminn-arnorgj]

According to RFC 959 section 3.1.1.5. Non-print format must be accepted by all FTP implementations. It's currently accepted if the format parameter is omitted as it is the default format control but if the second parameter is sent the current implementation breaks.

[drakkan]

Hello,

just for validation, do you have a client that sends A N? I looked at the profpd code and it seems to support A/L 7 and I/L 8 as ftpserverlib. Thanks

[codecov]

Codecov Report

Base: 86.25% // Head: 86.25% // No change to project coverage 👍

Coverage data is based on head (3c47833) compared to base (4c78a0b).
Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #391   +/-   ##
=======================================
  Coverage   86.25%   86.25%           
=======================================
  Files          11       11           
  Lines        1601     1601           
=======================================
  Hits         1381     1381           
  Misses        152      152           
  Partials       68       68           

Impacted Files	Coverage Δ
handle_misc.go	95.43% <100.00%> (ø)

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[siminn-arnorgj]

Hello,

just for validation, do you have a client that sends A N? I looked at the profpd code and it seems to support A/L 7 and I/L 8 as ftpserverlib. Thanks

Yes we have a legacy client that sends "TYPE A N". We encountered this when trying out SFTPgo 🙂 to replace an existing system.

[drakkan]

This legacy client will also have issues with proftpd 😄

I see that vsftpd handles A N

static void
handle_type(struct vsf_session* p_sess)
{
  str_upper(&p_sess->ftp_arg_str);
  if (str_equal_text(&p_sess->ftp_arg_str, "I") ||
      str_equal_text(&p_sess->ftp_arg_str, "L8") ||
      str_equal_text(&p_sess->ftp_arg_str, "L 8"))
  {
    p_sess->is_ascii = 0;
    vsf_cmdio_write(p_sess, FTP_TYPEOK, "Switching to Binary mode.");
  }
  else if (str_equal_text(&p_sess->ftp_arg_str, "A") ||
           str_equal_text(&p_sess->ftp_arg_str, "A N"))
  {
    p_sess->is_ascii = 1;
    vsf_cmdio_write(p_sess, FTP_TYPEOK, "Switching to ASCII mode.");
  }
  else
  {
    vsf_cmdio_write(p_sess, FTP_BADCMD, "Unrecognised TYPE command.");
  }
}

LGTM