[arch-releng] Fwd: [RFC] [PATCH] [archiso] Add support to mount iso in loopback mode.

[Baurzhan Muftakhidinov]

2010/12/1 Gerardo Exequiel Pozzi <vmlinuz386 at yahoo.com.ar>:
> Add two parameters:
>
> img_dev=/dev/sdNM
>   where /dev/sdNM is the device where .iso is located.
> img_loop=/path/to/arch.iso
>   where /path/to/arch.iso is the full path of the .iso in the device img_dev.
>
> Original idea from Baurzhan Muftakhidinov.
>
> Signed-off-by: Gerardo Exequiel Pozzi <vmlinuz386 at yahoo.com.ar>
> ---
>  archiso/Makefile                     |    2 ++
>  archiso/hooks/archiso_loop_mnt       |   33 +++++++++++++++++++++++++++++++++
>  archiso/install/archiso_loop_mnt     |   18 ++++++++++++++++++
>  configs/syslinux-iso/mkinitcpio.conf |    2 +-
>  4 files changed, 54 insertions(+), 1 deletions(-)
>  create mode 100644 archiso/hooks/archiso_loop_mnt
>  create mode 100644 archiso/install/archiso_loop_mnt
>
> diff --git a/archiso/Makefile b/archiso/Makefile
> index 688eb1b..93d68af 100644
> --- a/archiso/Makefile
> +++ b/archiso/Makefile
> @@ -10,6 +10,8 @@ install: all
>        install -D -m 644 install/archiso $(DESTDIR)/lib/initcpio/install/archiso
>        install -D -m 644 hooks/archiso_pxe_nbd $(DESTDIR)/lib/initcpio/hooks/archiso_pxe_nbd
>        install -D -m 644 install/archiso_pxe_nbd $(DESTDIR)/lib/initcpio/install/archiso_pxe_nbd
> +       install -D -m 644 hooks/archiso_loop_mnt $(DESTDIR)/lib/initcpio/hooks/archiso_loop_mnt
> +       install -D -m 644 install/archiso_loop_mnt $(DESTDIR)/lib/initcpio/install/archiso_loop_mnt
>        # install docs and examples
>        install -d -m 755 $(DESTDIR)/usr/share/archiso/
>        cp -r ../configs $(DESTDIR)/usr/share/archiso/configs
> diff --git a/archiso/hooks/archiso_loop_mnt b/archiso/hooks/archiso_loop_mnt
> new file mode 100644
> index 0000000..0d5eba7
> --- /dev/null
> +++ b/archiso/hooks/archiso_loop_mnt
> @@ -0,0 +1,33 @@
> +# vim: set ft=sh:
> +
> +run_hook () {
> +    if [ -n "${img_dev}" ] && [ -n "${img_loop}" ]; then
> +        mount_handler="archiso_loop_mount_handler"
> +    fi
> +}
> +
> +archiso_loop_mount_handler () {
> +    newroot="${1}"
> +
> +    while [ ! -b "${img_dev}" ]; do
> +        sleep 1
> +    done
> +
> +    msg "::: Setup a loop device from ${img_loop} located at device ${img_dev}"
> +    FSTYPE=$(blkid -o value -s TYPE -p ${img_dev} 2> /dev/null)
> +    if [ -n "${FSTYPE}" ]; then
> +        if mount -r -t "${FSTYPE}" ${img_dev} /img_dev > /dev/null 2>&1; then
> +            _dev_loop=$(losetup -f)
> +            losetup ${_dev_loop} /img_dev/${img_loop}
> +        fi
> +    fi
> +
> +    archiso_mount_handler ${newroot}
> +
> +    if [ "${copytoram}" = "y" ]; then
> +        msg "::: Deataching loop device ${_dev_loop}"
> +        losetup -d ${_dev_loop}
> +        msg "::: Unmounting ${img_dev}"
> +        umount ${img_dev}
> +    fi
> +}
> diff --git a/archiso/install/archiso_loop_mnt b/archiso/install/archiso_loop_mnt
> new file mode 100644
> index 0000000..c0d21a6
> --- /dev/null
> +++ b/archiso/install/archiso_loop_mnt
> @@ -0,0 +1,18 @@
> +# vim: set ft=sh:
> +
> +install ()
> +{
> +    MODULES=""
> +
> +    BINARIES=""
> +    FILES=""
> +    add_dir /img_dev
> +    SCRIPT="archiso_loop_mnt"
> +}
> +
> +help ()
> +{
> +cat<<HELPEOF
> +  This hook loads the necessary modules for boot via loop device.
> +HELPEOF
> +}
> diff --git a/configs/syslinux-iso/mkinitcpio.conf b/configs/syslinux-iso/mkinitcpio.conf
> index 15097c0..f5f8c79 100644
> --- a/configs/syslinux-iso/mkinitcpio.conf
> +++ b/configs/syslinux-iso/mkinitcpio.conf
> @@ -2,5 +2,5 @@
>  MODULES=""
>  BINARIES=""
>  FILES=""
> -HOOKS="base udev memdisk archiso archiso_pxe_nbd pata scsi sata usb fw pcmcia filesystems usbinput"
> +HOOKS="base udev memdisk archiso archiso_pxe_nbd archiso_loop_mnt pata scsi sata usb fw pcmcia filesystems usbinput"
>  COMPRESSION="lzma"
> --
> 1.7.3.2
>
>

Hi

This method does not work for me. I used Qemu to test it.

The boot process hangs at
'Waiting 30 seconds for device /dev/disk/by-name/' Thats it.
Which device should poll the archiso_mount_handler function? Is it USB
media, or ISO image?

Normal boot process as 'qemu -cdrom arch.iso' works fine.