[PATCH 1/1] udhcpc: don't exit after backgrounding on -n -b

[Denys Vlasenko]

Applied, thanks

On Tue, Feb 26, 2019 at 6:41 PM Andrey <ahippo at yandex.com> wrote:
>
>
> 26.02.2019, 11:20, "Denys Vlasenko" <vda.linux at googlemail.com>:
> > On Fri, Feb 22, 2019 at 10:46 PM <ahippo at yandex.com> wrote:
> >>  From: Andrey Mazo <ahippo at yandex.com>
> >>
> >>  Currently, running "udhcpc -n -b" causes udhcpc to go to background and
> >>  then exit after some time unless a lease is obtained.
> >>
> >>  It's not very useful to do so
> >>  as the calling process doesn't know
> >>  if the lease was obtained or not anyway.
> >>
> >>  The code actually tries to favor "-b" over "-n",
> >>  but doesn't clear "-n" flag while clearing "-b" after backgrounding.
> >>
> >>  So, clear "-n" flag after going into background.
> >>  This effectively makes "-b" override "-n" completely
> >>  and "-n -b" behave the same as "-b".
> >>
> >>  This allows to override default "-n" option, passed to udhcpc by ifupdown,
> >>  without recompiling busybox.
> >
> > To clarify: the goal is to deal with this situation:
> >
> > config IFUPDOWN_UDHCPC_CMD_OPTIONS
> >         string "ifup udhcpc command line options"
> >         default "-R -n"
> >
> > And %udhcpc_opts% only can _add_ options, not remove -n
> >
> > Thus, with default IFUPDOWN_UDHCPC_CMD_OPTIONS, -n is always passed?
> > This is the problem?
>
> Yes, exactly.
>
> An alternative solution is obviously to recompile busybox with IFUPDOWN_UDHCPC_CMD_OPTIONS="-R -b",
> but it may not be always feasible (like in my case).
>
> Would changing the defaults for IFUPDOWN_UDHCPC_CMD_OPTIONS to "-R -b" be a reasonable thing to do?
> For example, yocto uses "-R -b" [1, 2].
> If so, I can quickly cook up the patch.
>
> [1] http://git.yoctoproject.org/cgit/cgit.cgi/poky/tree/meta/recipes-core/busybox/busybox.inc#n131
> [2] https://bugzilla.yoctoproject.org/show_bug.cgi?id=6339
>
> Thank you,
> Andrey.