[PATCH] distro_boot: Fix bootfile env after calling boot_extlinux

[Simon Glass]

Hi Tom,

On Tue, 12 Oct 2021 at 13:44, Tom Rini <trini at konsulko.com> wrote:
>
> On Tue, Oct 12, 2021 at 04:55:44PM +0800, Artem Lapkin wrote:
>
> > Problem
> >
> > PXE cannot boot normally after Sysboot changed the bootfile env (called
> > from boot_extlinux) from the default "boot.scr.uimg" to
> > "/boot/extlinux/extlinux.conf".
> >
> > In addition, an unbootable extlinux configuration will also make the PXE
> > boot unbootable, because it will use the incorrect path "/boot/extlinux/"
> > from the bootfile env.
> >
> > Solution
> >
> > Save and restore default bootfile env value when boot_extlinux is used.
> >
> > Example
> > ================================================================
> > Hit SPACE in 2 seconds to stop autoboot
> > ... is now current device
> > Found /boot/extlinux/extlinux.conf
> > Retrieving file: /boot/extlinux/extlinux.conf
> > 413 bytes read in 2 ms (201.2 KiB/s)
> > Skipping Krescue for failure retrieving kernel
> > SCRIPT FAILED: continuing...
> > ...
> > Speed: 1000, full duplex
> > BOOTP broadcast 1
> > DHCP client bound to address 192.168.11.151 (8 ms)
> > Using ethernet at ff3f0000 device
> > TFTP from server 192.168.11.1; our IP address is 192.168.11.151
> > Filename '/boot/extlinux/pxelinux.cfg/default'.
> > Not retrying...
> > ================================================================
> >
> > Signed-off-by: Artem Lapkin <art at khadas.com>
> > ---
> >  include/config_distro_bootcmd.h | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/include/config_distro_bootcmd.h b/include/config_distro_bootcmd.h
> > index 3f724aa10f..db3d1b2362 100644
> > --- a/include/config_distro_bootcmd.h
> > +++ b/include/config_distro_bootcmd.h
> > @@ -445,7 +445,9 @@
> >                               "${devnum}:${distro_bootpart} "           \
> >                               "${prefix}${boot_syslinux_conf}; then "   \
> >                       "echo Found ${prefix}${boot_syslinux_conf}; "     \
> > +                     "bootfile_bak=${bootfile}; "                      \
> >                       "run boot_extlinux; "                             \
> > +                     "setenv bootfile ${bootfile_bak}; "               \
> >                       "echo SCRIPT FAILED: continuing...; "             \
> >               "fi\0"                                                    \
> >       \
>
> We've had this kind of problem before, and the answer is that variables
> should be local, not global in scope.  In this case, I see that the way
> the pxe/sysboot code works is that we have to env_set("..") in one place
> to env_get("..") in another, so I don't see a way around this.
>
> Reviewed-by: Tom Rini <trini at konsulko.com>

IMO a better approach will be the bootflow implementation. I hope to
get v2 out early next week.

Reviewed-by: Simon Glass <sjg at chromium.org>

Regards,
Simon