[syslinux] Append boot device to /proc/cmdline

[H. Peter Anvin]

On 11/28/2009 07:27 AM, Bernd Blaauw wrote:
> Op 28-11-2009 6:57, H. Peter Anvin schreef:
>> Hmmm... Syslinux already provides the filesystem type it is booted from
>> via the bootloader ID; there is some additional information that it can
>> provide, e.g. device type (fd,hd,cdrom,pxe), bios number, and partition
>> offset (if applicable for the device type.)  This doesn't automatically
>> map 1:1 onto the Linux device mappings, but it's probably the best that
>> one can do.
>>    
> 
> Memdisk-ISO means a hdd-booted (or USB-stick for that matter) ISO (in
> RAM) won't show you booted from harddisk if the ISO-image contains
> isolinux. It then shows last-used-bootloader-ID, which would be
> Isolinux, which then incorrectly implies you booted from physical CD
> (and thus are in trouble as CD drivers won't find any device, nor
> scripts will find the remainder of files on a disc in physical CD drive).
> 

Booting from a memdisk (or any of the myriad variations on the same
theme) is extra tricky, since they deliberately look like physical
devices... and could still be as far as the OS is concerned with
appropriate drivers.

The only way to really deal with that kind of stuff is by using
content-based identification, rather than device-based.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.