Hi,
Andreas Schwab <schwab@xxxxxxxxxxxxxx> writes:
> On Jun 20 2025, Junio C Hamano wrote:
>
>> Do we know symbolic port names are always limited to alnums? Or on
>> some systems some byte values in the fringe, like "_" or "-", are
>> also allowed?
>
> Valid service names are documented in RFC6335. Specifically it allows
> hyphens, but not underscores.
Thanks for the reference. I'm thinking at the moment to improve the
check for a valid port using something like this Scheme code:
--8<---------------cut here---------------start------------->8---
(define (port? port)
"Return the numeric value for PORT, else #f."
(if (and (exact-integer? port)
(positive? port)
(<= port (1- (expt 2 16))))
port
(catch 'system-error
(lambda () (servent:port (getservbyname port "")))
(const #f))))
scheme@(guile-user)> (port? "465")
$14 = #f
scheme@(guile-user)> (port? 465)
$15 = 465
scheme@(guile-user)> (port? "smtps")
$16 = 465
scheme@(guile-user)> (port? "unknown")
$17 = #f
scheme@(guile-user)> (port? 120000)
$18 = #f
--8<---------------cut here---------------end--------------->8---
So basically, try to call getservname(2) on a non-numeric port. If this
fails, the port is invalid, else return the port number.
--
Thanks,
Maxim
