Re: Help fixing NativeMessaging host: read 32-bit message length in native byte order

[Greg Wooledge]

On Sat, Jun 24, 2023 at 08:10:39AM -0700, guest271314 wrote:
> So, in the end, you can use something like this.
> 
>   length=$(dd iflag=fullblock bs=4 count=1 | od -An -td4)
>   length=$((length))      # trim leading spaces
>   IFS= read -rN"$length" json
> 
> That still winds up showing "Invalid byte sequence in conversion input"
> when echo'ing the output to a file.

Please show us the input.  Since it's binary, you'll need to represent
it in some way that can fit into an e-mail body.  Perhaps a hex dump of
the first 128 bytes or something.

I'm rather curious what possible input could be an "invalid byte sequence"
when interpreted as 32 bits that make up an integer.  Is it having the
high bit set (meaning negative when read as a signed integer)?

unicorn:~$ printf '\x00\x00\x00\x80' | od -An -td4
 -2147483648

Hmm, no, that looks all right to me.  Certainly didn't give that error.

What operating system and architecture are you on, and what input are you
using to generate this message, and which program is actually writing it?