Bug 568464 – [feature request] loopback.cfg grub ISO boot

• Status: CONFIRMED
• Product: Gentoo Release Media

[Description pille 2015-12-16 19:04:32 UTC]

i recently configured my grub2 to boot some linux live-CD/DVD-ISOs via
its loopback capability. while figuring out the parameters to get them
booted is extremly painful and error-prone. but i found a nice
"standard", which i'm asking you to implement.

it's boils down to provide a loopback.cfg inside the ISO that can be
sourced by grub's config and has access to some prepared variables.
i guess it can be generated without much overhead, since you need to
maintain your isolinux.cfg anyway.

that way i just need to point grub to the ISO and it's capable to boot
it. i'm currently using it to provide a Linux Mint for guest users of my
laptop, who don't have access to my FDE (except boot partition)

http://www.supergrubdisk.org/wiki/Loopback.cfg

[Comment 1 Jorge Manuel B. S. Vicetto (RETIRED) 2016-11-14 00:12:03 UTC]

Can you provide a patch for this?

[Comment 2 pille 2016-11-14 10:00:02 UTC]

not at this point. i may have a look if you point me to the CD bootloader config generation, though.

[Comment 3 Matt Turner 2019-02-02 20:34:54 UTC]

(In reply to pille from comment #2)
> not at this point. i may have a look if you point me to the CD bootloader
> config generation, though.

https://gitweb.gentoo.org/proj/catalyst.git/tree/targets/support/bootloader-setup.sh

[Comment 4 pille 2019-02-03 17:04:30 UTC]

Created attachment 563676 [details, diff]
patch that should enable generation of loopback.cfg at x86/amd64

thanks, here's an untested patch that should generate the necessary config-file.

[Comment 5 Matt Turner 2020-04-01 22:13:45 UTC]

Thanks. I can give this a try, but I don't know how to test it.

Can you explain how to use it?

[Comment 6 pille 2020-04-01 22:30:03 UTC]

1) create the ISO using the patch
2) verify, that loopback.cfg was generated along grub.cfg inside ISO
3) place ISO on /boot/boot-isos/
4) configure grub as described in the wiki link from my first comment
   or
   use supergrub2disk to boot the ISO (it has an autodetect/scan feature that iterates over all ISOs)

example:
  menuentry "gentoo.iso" {
    iso_path=/boot-isos/gentoo.iso
    export     iso_path
    search    --set=root --file $iso_path
    loopback   loop $iso_path
    root=(loop)
    configfile /boot/grub/loopback.cfg
    loopback   --delete loop
  }