I did something similar and found this to work well enough.
buf[0] is the character that was entered.
c is the number of characters collected so far on the current input line.
cmd[] is where it accumulates what has been typed so far.
What it does depends on whether the cursor is currently at the beginning
of a line or there is already some text entered.
Either way, sending '\b' will just move the cursor. So to get rid of a
character, you back up one character, then replace it with a literal
space and then back up again so the next character entered will be where
you expect it.
if ( (buf[0] == 0x7f || buf[0] == CTRL('H')) )
{
if ( c > 0 )
{
cmd[--c] = 0;
// back up, space over the character, then back up again
ssh_channel_write(channel, "\b \b", 3);
}
else
// clear any visible character
// there is a prompt shown, so we don't allow backing up
any farther than that
ssh_channel_write(channel, " \b", 2); // fix the client side
}
Mike Jones
On 8/7/2014 1:41 PM, Barbe, Charles wrote:
> Hi,
>
> I am attempting to implement a very simple ssh shell server for use on an
> embedded platform that has a custom shell. I am able to successfully
> establish the connection, take in commands and spit out the results. My
> question though is how does one handle echoing command inputs correctly,
> particularly with respect to the backspace key.
>
> Currently, my echoing is just going through my normal stdout - with a
> "printf("%c", character) as each character is received - which is being
> written out to the ssh channel. But this does not seem to work with things
> like the backspace key.
>
> Am i missing something?
>
> Thanks for any help you can provide!
>
> Charles A. Barbe
> Senior Software Engineer
> Allworx, a Windstream company
> 245 East Main St | Rochester NY | 14604
> [email protected] | 585.421.5565
>
>
