Re: bin/59587: ftp client ascii transfers with progress report fail

[Taylor R Campbell <riastradh%NetBSD.org@localhost>]

> Date: Thu, 15 Jan 2026 03:51:28 +0000
> From: Taylor R Campbell <riastradh%NetBSD.org@localhost>
> 
> > Module Name:    src
> > Committed By:   lukem
> > Date:           Sat Dec  6 06:20:23 UTC 2025
> > 
> > Modified Files:
> >         src/usr.bin/ftp: extern.h ftp.c util.c version.h
> > 
> > Log Message:
> > ftp: fix ascii transfers with progress bar
> > 
> > Handle stdio interruption by signals and improve error handling
> > in getc() and putc() on the control and data channels.
> > Provide ftp_getc() and ftp_putc() wrappers that:
> > - Retry the operation on EINTR or EAGAIN instead of failing.

Alternatively: Why not use SA_RESTART, so you don't have to track down
all the I/O logic that might be interrupted by a signal and arrange to
run it in a loop?

There's nothing here that behaves differently if it received a signal,
like printing a progress bar if the I/O was interrupted by a signal --
that's already done in the signal handler itself, isn't it?

(Except you should probably use snprintf_ss, not snprintf, in
progressbar.c, if you want to print the progress bar in the signal
handler itself: snprintf is technically not async-signal-safe.  In
practice on NetBSD, though, I think it matters only for the
floating-point formatters, which may use malloc in gdtoa; the rest of
it like %d and %s is probably safe.)