Syslinux - Sep 2017 - Fallback to second menu entry, ONERROR looping forever

Hello

I want to fallback to a second boot entry, if the kernel is missing for 
the first entry.

So I through I could use ONERROR, but syslinux just continue to try 
starting the first entry.

Am I doing something wrong? or can't this be done with syslinux?


default menu.c32
prompt 0

MENU HIDDEN
MENU AUTOBOOT
TIMEOUT 2
ONERROR live-generic

label grub
 ??? menu label ^Grub
 ??? menu default
 ??? linux /boot/grub/lnxboot.img
 ??? initrd /boot/grub/core.img

label live-generic
 ??? menu label ^Live (generic)
 ??? linux /live/vmlinuz
 ??? initrd /live/initrd.img
 ??? append boot=live quiet splash nonetworking

- Kristian Klausen

On Sun, Sep 24, 2017 at 4:44 PM, Kristian Klausen via Syslinux
<syslinux at zytor.com> wrote:
> Hello
>
> I want to fallback to a second boot entry, if the kernel is missing for
> the first entry.
>
> So I through I could use ONERROR, but syslinux just continue to try
> starting the first entry.
>
> Am I doing something wrong? or can't this be done with syslinux?
I snipped the config to later.
> - Kristian Klausen
What version of Syslinux from what build/source is being used?


On Wed, Sep 27, 2017 at 12:43 AM, TorgeirW via Syslinux
<syslinux at zytor.com> wrote:
> Hi!
>
> I think thats the whole point with ONERROR.
> We use it in PXELINUX with a reload label.
>
> So we can reload pxelinux (ONERROR) if someone types something wrong
?intall? instead of ?install?.
>
> ?
> Torgeir
It is the point of ONERROR however, the menu might be adding to confusion.

I personally try to use uppercase on the directives as it makes
knowing what is or is not directives a little easier.

Let's look at the emailed config:
> default menu.c32
This should be:

DEFAULT grub
UI menu.c32

Though to see what's wrong, I'd suggest commenting out the
"UI" line.
> prompt 0
For diagnostics, let's use "PROMPT 1".
> MENU HIDDEN
> MENU AUTOBOOT
> TIMEOUT 2
For testing, I'd suggest increasing TIMEOUT to a human value of say
600 (60 seconds) or set to 0 (around 13 years).
> ONERROR live-generic
>
> label grub
>      menu label ^Grub
>      menu default
>      linux /boot/grub/lnxboot.img
>      initrd /boot/grub/core.img
>
> label live-generic
>      menu label ^Live (generic)
>      linux /live/vmlinuz
>      initrd /live/initrd.img
>      append boot=live quiet splash nonetworking
Your LABELs are clean names and non-ambiguous in the first character.
You've used MENU LABEL for human descriptions with special characters
like spaces and parentheses.  With the change to DEFAULT, there's
almost no need for MENU DEFAULT though it shouldn't be hurting
anything.

I seem to recall something about error-like conditions not triggering
a proper error state and using ONERROR but at least these changes
should show more of what's going on underneath.

-- 
-Gene

Hello Gene


On 27-09-2017 12:36, Gene Cumm wrote:
> On Sun, Sep 24, 2017 at 4:44 PM, Kristian Klausen via Syslinux
> <syslinux at zytor.com> wrote:
>> Hello
>>
>> I want to fallback to a second boot entry, if the kernel is missing for
>> the first entry.
>>
>> So I through I could use ONERROR, but syslinux just continue to try
>> starting the first entry.
>>
>> Am I doing something wrong? or can't this be done with syslinux?
> I snipped the config to later.
>
>> - Kristian Klausen
> What version of Syslinux from what build/source is being used?
I have no idea really. They was added to the Git repo on June 18th 2015, 
so they "old".
I tried strings *.c32, to look for a version string but couldn't find 
any. I have attached the file, if you have any idea how I can figure out 
the version.
>
> On Wed, Sep 27, 2017 at 12:43 AM, TorgeirW via Syslinux
> <syslinux at zytor.com> wrote:
>> Hi!
>>
>> I think thats the whole point with ONERROR.
>> We use it in PXELINUX with a reload label.
>>
>> So we can reload pxelinux (ONERROR) if someone types something wrong
?intall? instead of ?install?.
>>
>> ?
>> Torgeir
> It is the point of ONERROR however, the menu might be adding to confusion.
>
> I personally try to use uppercase on the directives as it makes
> knowing what is or is not directives a little easier.
>
> Let's look at the emailed config:
>
>> default menu.c32
> This should be:
>
> DEFAULT grub
> UI menu.c32
>
> Though to see what's wrong, I'd suggest commenting out the
"UI" line.
>
>> prompt 0
> For diagnostics, let's use "PROMPT 1".
I just tried that, but it didn't really change anything. I still just 
get about that syslinux can't find the kernel, and it then just retries 
forever.
>
>> MENU HIDDEN
>> MENU AUTOBOOT
>> TIMEOUT 2
> For testing, I'd suggest increasing TIMEOUT to a human value of say
> 600 (60 seconds) or set to 0 (around 13 years).
>
>> ONERROR live-generic
>>
>> label grub
>>       menu label ^Grub
>>       menu default
>>       linux /boot/grub/lnxboot.img
>>       initrd /boot/grub/core.img
>>
>> label live-generic
>>       menu label ^Live (generic)
>>       linux /live/vmlinuz
>>       initrd /live/initrd.img
>>       append boot=live quiet splash nonetworking
> Your LABELs are clean names and non-ambiguous in the first character.
> You've used MENU LABEL for human descriptions with special characters
> like spaces and parentheses.  With the change to DEFAULT, there's
> almost no need for MENU DEFAULT though it shouldn't be hurting
> anything.
>
> I seem to recall something about error-like conditions not triggering
> a proper error state and using ONERROR but at least these changes
> should show more of what's going on underneath.
>
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> On Sun, Sep 24, 2017 at 4:44 PM, Kristian Klausen via Syslinux
> <syslinux at zytor.com> wrote:
> > Hello
> >
> > I want to fallback to a second boot entry, if the kernel is missing
for
> > the first entry.
> >
> > So I through I could use ONERROR, but syslinux just continue to try
> > starting the first entry.
> >
> > Am I doing something wrong? or can't this be done with syslinux?
> 
> I snipped the config to later.
> 
> > - Kristian Klausen
> 
> What version of Syslinux from what build/source is being used?
> 
> 
> On Wed, Sep 27, 2017 at 12:43 AM, TorgeirW via Syslinux
> <syslinux at zytor.com> wrote:
> > Hi!
> >
> > I think thats the whole point with ONERROR.
> > We use it in PXELINUX with a reload label.
> >
> > So we can reload pxelinux (ONERROR) if someone types something wrong
?intall? instead of ?install?.
> >
> > ?
> > Torgeir
> 
> It is the point of ONERROR however, the menu might be adding to confusion.
 
 
The practical use-cases of ONERROR are very limited. Naturally, users 
tend to think that when the selected item fails to launch, then 
Syslinux would simply try to load whatever is specified after ONERROR. 
Unfortunately, this is not how it works.

Regards,
Ady.