Commit 7080eef9 authored by Thomas Petazzoni's avatar Thomas Petazzoni
Browse files

fs/iso9660: support building a real iso9660 filesystem 



Until now, the iso9660 filesystem handling only supported using an
initrd/initramfs to store the root filesystem, which is very different
from what we do with the other filesystems.

This commit changes the iso9660 logic to also allow using directly an
iso9660 filesystem to store the root filesystem. A new option,
BR2_TARGET_ROOTFS_ISO9660_INITRD, is created to tell the iso9660 that
we want to use an initrd and not directly the root filesystem in
iso9660 format. This option defaults to 'y' to preserve the existing
behavior.

After this commit, we therefore have three possibilities:

 * BR2_TARGET_ROOTFS_ISO9660=y, with BR2_TARGET_ROOTFS_INITRAMFS and
   BR2_TARGET_ROOTFS_ISO9660_INITRD disabled. In this case, the
   iso9660 filesystem is directly the contents of the root filesystem
   (since is possible thanks to the Rockridge extensions that were
   already enabled using the -R option of genisoimage). Obviously, it
   means that the root filesystem is read-only.

 * BR2_TARGET_ROOTFS_ISO9660=y and BR2_TARGET_ROOTFS_INITRAMFS=y (the
   value of BR2_TARGET_ROOTFS_ISO9660_INITRD doesn't matter). In this
   case, the root filesystem is already linked into the kernel image
   itself, as an initramfs. So the iso9660 filesystem doesn't contain
   the root filesystem as is, but just the bootloader and the kernel
   image.

 * BR2_TARGET_ROOTFS_ISO9660=y, BR2_TARGET_ROOTFS_ISO9660_INITRD=y and
   BR2_TARGET_ROOTFS_INITRAMFS disabled. In this case, a separate
   initrd is used. The iso9660 filesystem only contains the
   bootloader, the kernel and the initrd.

In order to support the first case out of the box, root=/dev/sr0 is
added on the kernel command line in the example Grub configuration
file, so that the kernel knows where the root filesystem is
located. This argument is ignored when initrd/initramfs are used.

Signed-off-by: default avatarThomas Petazzoni <thomas.petazzoni@free-electrons.com>
Reviewed-by: default avatar"Yann E. MORIN" <yann.morin.1998@free.fr>
parent 168cce04

fs/iso9660/Config.in

+25 −2
Original line number Diff line number Diff line
@@ -2,11 +2,23 @@ config BR2_TARGET_ROOTFS_ISO9660 
	bool "iso image"

	depends on (BR2_i386 || BR2_x86_64)

	depends on BR2_LINUX_KERNEL

	select BR2_TARGET_ROOTFS_CPIO

	select BR2_LINUX_KERNEL_INSTALL_TARGET \

	       if (!BR2_TARGET_ROOTFS_ISO9660_INITRD && !BR2_TARGET_ROOTFS_INITRAMFS)

	select BR2_TARGET_GRUB

	select BR2_TARGET_GRUB_FS_ISO9660

	help

	  Build a bootable iso9660 image

	  Build a bootable ISO9660 image. By default, the root

	  filesystem is directly packed as the ISO9660 filesystem,

	  which means the root filesystem will be read-only. It

	  requires ISO9660 filesystem support and CDROM support in the

	  kernel.



	  However, if BR2_TARGET_ROOTFS_INITRAMFS or

	  BR2_TARGET_ROOTFS_ISO9660_INITRD have been enabled, the

	  ISO9660 filesystem will only contain a kernel image and

	  optionally an external initrd image. In this case, the

	  filesystem being in RAM, it will be read/write. No ISO9660

	  or CDROM support is needed in the kernel.



if BR2_TARGET_ROOTFS_ISO9660
@@ -19,6 +31,17 @@ config BR2_TARGET_ROOTFS_ISO9660_BOOT_MENU 
	  automatically be replaced by the path to the kernel and

	  initrd images respectively.



config BR2_TARGET_ROOTFS_ISO9660_INITRD

	bool "Use initrd"

	default y

	select BR2_TARGET_ROOTFS_CPIO

	help

	  Enable this option to have the root filesystem bundled as an

	  initrd/initramfs rather than directly as the ISO9660

	  filesystem. With this option enabled, the ISO9660 will only

	  contain a kernel image, an initrd image (unless an initramfs

	  linked into the kernel is used) and the bootloader.



endif



comment "iso image needs a Linux kernel to be built"

fs/iso9660/iso9660.mk

+84 −25
Original line number Diff line number Diff line
@@ -4,51 +4,110 @@ 
#

################################################################################



ROOTFS_ISO9660_TARGET_DIR = $(BUILD_DIR)/rootfs-iso9660.tmp

#

# We need to handle three cases:

#

#  1. The ISO9660 filesystem will really be the real root filesystem

#     itself. This is when BR2_TARGET_ROOTFS_ISO9660_INITRD is

#     disabled.

#

#  2. The ISO9660 filesystem will be a filesystem with just a kernel

#     image, initrd and grub. This is when

#     BR2_TARGET_ROOTFS_ISO9660_INITRD is enabled, but

#     BR2_TARGET_ROOTFS_INITRAMFS is disabled.

#

#  3. The ISO9660 filesystem will be a filesystem with just a kernel

#     image and grub. This is like (2), except that the initrd is

#     built into the kernel image. This is when

#     BR2_TARGET_ROOTFS_INITRAMFS is enabled (regardless of the value

#     of BR2_TARGET_ROOTFS_ISO9660_INITRD).



ROOTFS_ISO9660_BOOT_MENU = $(call qstrip,$(BR2_TARGET_ROOTFS_ISO9660_BOOT_MENU))



ROOTFS_ISO9660_DEPENDENCIES = grub host-cdrkit host-fakeroot linux rootfs-cpio

ROOTFS_ISO9660_DEPENDENCIES = grub host-cdrkit host-fakeroot linux



ifeq ($(BR2_TARGET_GRUB_SPLASH),y)

define ROOTFS_ISO9660_SPLASHSCREEN

	$(INSTALL) -D -m 0644 $(TARGET_DIR)/boot/grub/splash.xpm.gz \

		$(ROOTFS_ISO9660_TARGET_DIR)/boot/grub/splash.xpm.gz

ifeq ($(BR2_TARGET_ROOTFS_INITRAMFS),y)

ROOTFS_ISO9660_USE_INITRD = YES

endif



ifeq ($(BR2_TARGET_ROOTFS_ISO9660_INITRD),y)

ROOTFS_ISO9660_USE_INITRD = YES

endif



ifeq ($(ROOTFS_ISO9660_USE_INITRD),YES)

ROOTFS_ISO9660_TARGET_DIR = $(BUILD_DIR)/rootfs-iso9660.tmp

define ROOTFS_ISO9660_CREATE_TEMPDIR

	$(RM) -rf $(ROOTFS_ISO9660_TARGET_DIR)

	mkdir -p $(ROOTFS_ISO9660_TARGET_DIR)

endef

else

define ROOTFS_ISO9660_SPLASHSCREEN

ROOTFS_ISO9660_TARGET_DIR = $(TARGET_DIR)

endif



define ROOTFS_ISO9660_PREPARATION

	$(INSTALL) -D -m 0644 $(GRUB_DIR)/stage2/stage2_eltorito \

		$(ROOTFS_ISO9660_TARGET_DIR)/boot/grub/stage2_eltorito

	$(INSTALL) -D -m 0644 $(ROOTFS_ISO9660_BOOT_MENU) \

		$(ROOTFS_ISO9660_TARGET_DIR)/boot/grub/menu.lst

	$(SED) "s%__KERNEL_PATH__%/boot/$(LINUX_IMAGE_NAME)%" \

		$(ROOTFS_ISO9660_TARGET_DIR)/boot/grub/menu.lst

endef



ROOTFS_ISO9660_PRE_GEN_HOOKS += ROOTFS_ISO9660_PREPARATION



# Splash screen disabling

ifeq ($(BR2_TARGET_GRUB_SPLASH),)

define ROOTFS_ISO9660_DISABLE_SPLASHSCREEN

	$(SED) '/^splashimage/d' $(ROOTFS_ISO9660_TARGET_DIR)/boot/grub/menu.lst

endef

ROOTFS_ISO9660_PRE_GEN_HOOKS += ROOTFS_ISO9660_DISABLE_SPLASHSCREEN

endif



ifeq ($(BR2_TARGET_ROOTFS_INITRAMFS),y)

define ROOTFS_ISO9660_INITRD

define ROOTFS_ISO9660_DISABLE_EXTERNAL_INITRD

	$(SED) '/__INITRD_PATH__/d'  $(ROOTFS_ISO9660_TARGET_DIR)/boot/grub/menu.lst

endef



ifeq ($(ROOTFS_ISO9660_USE_INITRD),YES)



# Copy splashscreen to temporary filesystem

ifeq ($(BR2_TARGET_GRUB_SPLASH),y)

define ROOTFS_ISO9660_INSTALL_SPLASHSCREEN

	$(INSTALL) -D -m 0644 $(TARGET_DIR)/boot/grub/splash.xpm.gz \

		$(ROOTFS_ISO9660_TARGET_DIR)/boot/grub/splash.xpm.gz

endef

ROOTFS_ISO9660_PRE_GEN_HOOKS += ROOTFS_ISO9660_INSTALL_SPLASHSCREEN

endif



# Copy the kernel to temporary filesystem

define ROOTFS_ISO9660_COPY_KERNEL

	$(INSTALL) -D -m 0644 $(LINUX_IMAGE_PATH) \

		$(ROOTFS_ISO9660_TARGET_DIR)/boot/$(LINUX_IMAGE_NAME)

endef



ROOTFS_ISO9660_PRE_GEN_HOOKS += ROOTFS_ISO9660_COPY_KERNEL



# If initramfs is used, disable loading the initrd as the rootfs is

# already inside the kernel image. Otherwise, make sure a cpio is

# generated and use it as the initrd.

ifeq ($(BR2_TARGET_ROOTFS_INITRAMFS),y)

ROOTFS_ISO9660_PRE_GEN_HOOKS += ROOTFS_ISO9660_DISABLE_EXTERNAL_INITRD

else

define ROOTFS_ISO9660_INITRD

ROOTFS_ISO9660_DEPENDENCIES += rootfs-cpio

define ROOTFS_ISO9660_COPY_INITRD

	$(INSTALL) -D -m 0644 $(BINARIES_DIR)/rootfs.cpio$(ROOTFS_CPIO_COMPRESS_EXT) \

		$(ROOTFS_ISO9660_TARGET_DIR)/boot/initrd

	$(SED) "s%__INITRD_PATH__%/boot/initrd%" \

		$(ROOTFS_ISO9660_TARGET_DIR)/boot/grub/menu.lst

endef

ROOTFS_ISO9660_PRE_GEN_HOOKS += ROOTFS_ISO9660_COPY_INITRD

endif



define ROOTFS_ISO9660_PREPARATION

	$(RM) -rf $(ROOTFS_ISO9660_TARGET_DIR)

	mkdir -p $(ROOTFS_ISO9660_TARGET_DIR)

	$(INSTALL) -D -m 0644 $(GRUB_DIR)/stage2/stage2_eltorito \

		$(ROOTFS_ISO9660_TARGET_DIR)/boot/grub/stage2_eltorito

	$(INSTALL) -D -m 0644 $(ROOTFS_ISO9660_BOOT_MENU) \

		$(ROOTFS_ISO9660_TARGET_DIR)/boot/grub/menu.lst

	$(INSTALL) -D -m 0644 $(LINUX_IMAGE_PATH) \

		$(ROOTFS_ISO9660_TARGET_DIR)/boot/$(LINUX_IMAGE_NAME)

	$(SED) "s%__KERNEL_PATH__%/boot/$(LINUX_IMAGE_NAME)%" \

		$(ROOTFS_ISO9660_TARGET_DIR)/boot/grub/menu.lst

	$(ROOTFS_ISO9660_SPLASHSCREEN)

	$(ROOTFS_ISO9660_INITRD)

endef

else # ROOTFS_ISO9660_USE_INITRD



ROOTFS_ISO9660_PRE_GEN_HOOKS += ROOTFS_ISO9660_DISABLE_EXTERNAL_INITRD



endif # ROOTFS_ISO9660_USE_INITRD



ROOTFS_ISO9660_PRE_GEN_HOOKS += ROOTFS_ISO9660_PREPARATION



define ROOTFS_ISO9660_CMD

	$(HOST_DIR)/usr/bin/genisoimage -J -R -b boot/grub/stage2_eltorito \

fs/iso9660/menu.lst

+1 −1
Original line number Diff line number Diff line
@@ -12,7 +12,7 @@ foreground 000000 
background 	cccccc



title		Buildroot ISO9660 image

kernel		__KERNEL_PATH__

kernel		__KERNEL_PATH__ root=/dev/sr0

initrd		__INITRD_PATH__



title		Hard Drive (first partition)