Core OS Index

1.4. Prepare for Reboot

Follow this instructions with active chroot, first mount partitions and before chroot mount follow file systems;

        $ sudo mount --bind /dev $CHROOT/dev
        $ sudo mount -vt devpts devpts $CHROOT/dev/pts
        $ sudo mount -vt tmpfs shm $CHROOT/dev/shm
        $ sudo mount -vt proc proc $CHROOT/proc
        $ sudo mount -vt sysfs sysfs $CHROOT/sys

Now you can chroot;

        $ sudo chroot $CHROOT /usr/bin/env -i \
          HOME=/root TERM="$TERM" PS1='\u:\w\$ ' \
          PATH=/bin:/usr/bin:/sbin:/usr/sbin \
          /bin/bash --login

1.4.1. Port kernel

Core ports have two linux kernels, linux-libre and linux-blob. Port linux-libre kernel is a true source based kernel that respects your freedoms, is x86_64 but not generic configured, select modules (drivers) for your hardware, for example correct graphic driver and disk. Port linux-blob is dangerous, contain blobs (from bad corporations).

Both ports apply grsecurity patch and are configured in a way that break building some packages and have performance impact in building process. Solution is to have several kernels, production, testing, debug with one of them without grsecurity.

        # cd /usr/ports/c9-ports/linux-libre
        # pkgmk -d
        # pkgadd /usr/ports/packages/linux-libre#4.9.11-2.pkg.tar.gz

1.4.3. Configuring Grub2

Create grub file in /etc/default/grub with values;

        GRUB_DISABLE_LINUX_UUID=false
        GRUB_ENABLE_LINUX_LABEL=false

Grub Manual, install grub on MBR of disk sdb;

        # grub-install /dev/sdb
        Installation finished. No error reported.

If you are installing on removable media;

        # grub-install --removable /dev/sdb
        Installation finished. No error reported.

grub-mkconfig generates grub.cfg, it will try to discover available kernels and attempt to generate menu entries for them;

        # grub-mkconfig -o /boot/grub/grub.cfg
        Generating grub.cfg ...
        Found linux image: /boot/vmlinuz-4.1.30-crux
        Found initrd image: /boot/initramfs-4.1.30-crux.img
        done
        #

Check /boot/grub/grub.cfg, if is wrong add menu to /etc/grub.d/40_custom, replace correct partition from grub-prob output and correct UUID from fstab or blkid

        # grub-probe --target=hints_string /

1.4.3.1. Rescue iso

Simple way to have "resque" system is to mount boot as read only, this assures that even as root nothing can be changed without remount. To have different system independent from host grub will have entry to boot small iso on /boot partition;

Crux iso is not used because at the moment it fails to find "crux-media" during or after init.

        $ wget http://ftp.nluug.nl/os/Linux/distr/tinycorelinux/7.x/x86/release/CorePlus-current.iso
        $ sudo mv CorePlus-current.iso /boot/tinycore.iso

Edit /etc/grub.d/40_custom

menuentry "Rescue" { load_video set gfxpayload=keep set isofile="/tinycore.iso" loopback loop $isofile linux (loop)/boot/vmlinuz64 loglevel=3 cde initrd (loop)/boot/corepure64.gz }

1.4.4. Checkup

If you have qemu installed you can see if it boots, in this example sdb is usb external drive;

        # qemu-system-x86_64 -kernel /boot/vmlinuz-linux -initrd /boot/initramfs-linux.img -append root=/dev/sdb /dev/sdb2

Debug Grub

Debug initram

        /usr/lib/dracut/skipcpio /boot/initramfs-4.9.11-blob.img | gunzip -c | cpio -i -d
        36875 blocks

Core OS Index