[OE-core] [PATCH V7 0/6] read-only rootfs support

[Qi.Chen at windriver.com]

From: Chen Qi <Qi.Chen at windriver.com>

The series of patches add support to read-only rootfs.

The main idea is to use symbolic links to create the illuion that some
directories are writable in case of a read-only rootfs.

This set of patches have been tested on minimal images with and without
'read-only-rootfs' image feature enabled. Everything is OK.

For sato images, everything is the same as before if 'read-only-rootfs' is not enabled.
With 'read-only-rootfs' enabled, sato image could work if graphic interface is diabled.
When all postinstall problems are resolved, sato image should work well (maybe with some
small changes in volatiles-readonly-sato conf file).

Changes for Version 4:
1) Improve the commit messages to be clearer.
2) Use 'sed -i' to replace 'sed' and 'mv' operations to cut down the exec overhead.

Changes for Version 5:
Fix the problem of failing to build the live images

Changes for Version 6:
1) Let the image recipes provide the corresponding conf files for read-only rootfs.
   The config files are closely related to the image types, so it's more reasonable
   to let these image recipes provide the config files.
2) Support customized conf files for customized images.

Changes for Version 7:
1) Separate read-only-rootfs specific conf files from image recipes.
   Create recipes for them and let image recipes depend on the them.
2) 'choose_volatiel_conf' is no more need, thus removed.


The following changes since commit 53cc748b93e8af584557d6db5309c3e955182c5c:

  linux-libc-headers: fix headers install in long path name environments (2013-01-10 23:53:51 +0000)

are available in the git repository at:

  git://git.pokylinux.org/poky-contrib ChenQi/readonly-rootfs
  http://git.pokylinux.org/cgit.cgi/poky-contrib/log/?h=ChenQi/readonly-rootfs

Chen Qi (6):
  sysvinit: add ROOTFS_READ_ONLY variable to rcS-default
  image.bbclass: add a hook funtion to support readonly rootfs
  core-image.bbclass: support read-only rootfs
  initscripts: support read-only rootfs
  volatile-conf-minimal: add recipe
  volatile-conf-sato: add recipe

 meta/classes/core-image.bbclass                    |    5 +-
 meta/classes/image.bbclass                         |   16 +-
 meta/recipes-core/images/core-image-minimal.bb     |    3 +
 .../initscripts/initscripts-1.0/bootmisc.sh        |    9 +-
 .../initscripts-1.0/populate-volatile.sh           |  281 ++++++++++----------
 .../initscripts/initscripts-1.0/volatiles          |    1 +
 meta/recipes-core/initscripts/initscripts_1.0.bb   |    5 +-
 .../files/volatiles-readonly-minimal               |    8 +
 .../volatile-conf-minimal_1.0.bb                   |   15 ++
 meta/recipes-core/sysvinit/sysvinit/rcS-default    |    4 +
 meta/recipes-core/sysvinit/sysvinit_2.88dsf.bb     |    2 +-
 meta/recipes-sato/images/core-image-sato.bb        |    3 +
 .../files/volatiles-readonly-sato                  |   14 +
 .../volatile-conf-sato_1.0.bb                      |   15 ++
 14 files changed, 224 insertions(+), 157 deletions(-)
 create mode 100644 meta/recipes-core/readonly-volatile-conf/files/volatiles-readonly-minimal
 create mode 100644 meta/recipes-core/readonly-volatile-conf/volatile-conf-minimal_1.0.bb
 create mode 100644 meta/recipes-sato/readonly-volatile-conf/files/volatiles-readonly-sato
 create mode 100644 meta/recipes-sato/readonly-volatile-conf/volatile-conf-sato_1.0.bb

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1.7.9.5