support/deny-rsync

   1 #!/usr/bin/env bash
   2 # Send an error message via the rsync-protocol to a non-daemon client rsync.
   3 #
   4 # Usage:  deny-rsync "message"
   5
   6 protocol_version=29
   7 exit_code=4 # same as a daemon that refuses an option
   8
   9 # e.g. byte_escape 29 => \035
  10 function byte_escape {
  11     echo -ne "\\0$(printf "%o" $1)"
  12 }
  13
  14 msg="$1"
  15 if [ "${#msg}" -gt 254 ]; then
  16     # truncate a message that is too long for this naive script to handle
  17     msg="${msg:0:251}..."
  18 fi
  19 msglen=$(( ${#msg} + 1 )) # add 1 for the newline we append below
  20
  21 # Send protocol version.  All numbers are LSB-first 4-byte ints.
  22 echo -ne "$(byte_escape $protocol_version)\\000\\000\\000"
  23
  24 # Send a zero checksum seed.
  25 echo -ne "\\000\\000\\000\\000"
  26
  27 # The following is equivalent to rprintf(FERROR_XFER, "%s\n", $msg).
  28 # 1. Message header: ((MPLEX_BASE + FERROR_XFER) << 24) + $msglen.
  29 echo -ne "$(byte_escape $msglen)\\000\\000\\010"
  30 # 2. The actual data.
  31 echo -E "$msg"
  32
  33 # Make sure the client gets our message, not a write failure.
  34 sleep 1
  35
  36 exit $exit_code