[OE-core] [PATCH 02/12] image.bbclass: add a hook funtion to support readonly rootfs

[ChenQi]

On 01/25/2013 03:44 AM, Mark Hatle wrote:
> On 1/24/13 2:16 AM, Qi.Chen at windriver.com wrote:
>> From: Chen Qi <Qi.Chen at windriver.com>
>>
>> read_only_rootfs_hook: this funtion is invoked only if 
>> 'read-only-rootfs'
>> is in IMAGE_FEATURES. It tweaks some basic files and makes populate-
>> volatile.sh script run at rootfs time.
>>
>> For now, it has real effect only if the init system is sysvinit.
>>
>> [YOCTO #3406]
>>
>> Signed-off-by: Chen Qi <Qi.Chen at windriver.com>
>> ---
>>   meta/classes/image.bbclass |   18 ++++++++++++++++++
>>   1 file changed, 18 insertions(+)
>>
>> diff --git a/meta/classes/image.bbclass b/meta/classes/image.bbclass
>> index 0293d2e..91045fc 100644
>> --- a/meta/classes/image.bbclass
>> +++ b/meta/classes/image.bbclass
>> @@ -201,6 +201,24 @@ run_intercept_scriptlets () {
>>       fi
>>   }
>>
>> +# A hook function to support read-only-rootfs IMAGE_FEATURES
>> +# Currently, it only supports sysvinit system.
>> +read_only_rootfs_hook () {
>> +    if ${@base_contains("DISTRO_FEATURES", "sysvinit", "true", 
>> "false", d)}; then
>> +            # Tweak the mount option in fstab
>> +        sed -i '/rootfs/ s/defaults/ro/' ${IMAGE_ROOTFS}/etc/fstab
>
> There is a slight bug in the above.  Not all configurations will 
> contain an /etc/fstab!  So you need to check for the existence of the 
> file before you try to sed it.
>
> (Initramfs is where I hit a problem trying to test this.)
>
> --Mark
>

Thank you for pointing it out. I'll fix it.

Thanks,
Chen Qi

>> +            # Change the value of ROOTFS_READ_ONLY in 
>> /etc/default/rcS to yes
>> +        if [ -e ${IMAGE_ROOTFS}/etc/default/rcS ]; then
>> +            sed -i 's/ROOTFS_READ_ONLY=no/ROOTFS_READ_ONLY=yes/' 
>> ${IMAGE_ROOTFS}/etc/default/rcS
>> +        fi
>> +            # Run populate-volatile.sh at rootfs time to set up 
>> basic files
>> +            # and directories to support read-only rootfs.
>> +        if [ -e ${IMAGE_ROOTFS}/etc/init.d/populate-volatile.sh ]; then
>> +            ${IMAGE_ROOTFS}/etc/init.d/populate-volatile.sh
>> +        fi
>> +    fi
>> +}
>> +
>>   fakeroot do_rootfs () {
>>       #set -x
>>       # When use the rpm incremental image generation, don't remove 
>> the rootfs
>>
>
>
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