2010-04-26 09:29:07     How to handle few rw files using cramfs

2010-04-26 09:29:07     How to handle few rw files using cramfs

Jayaprabhu Nadarajan (INDIA)

Message: 88903   

Hi,

I am trying to use cramfs file system for my flash in BF527 board.

I have made 5 MTD partitions. In One Partition i have flashed kernel-only image(vmImage in mtd2) and in the other partition i have flashed cramfs (rootfs.cramfs in mtd3)

I am using the following boot command "init=/sbin/init root=/dev/mtdblock3 ro rootfstype=cramfs" and i am able to boot my flashed kernel successfully.

My application requires write permission for writing into some of the files like /etc/resolv.conf, /etc/config/smb.conf etc. How do i manage similar kind of files which requires both rw permission, using cramfs which is read only.

Regards,

Jp

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2010-04-26 11:37:46     Re: How to handle few rw files using cramfs

Mike Frysinger (UNITED STATES)

Message: 88908   

so symlink the files to somewhere you can write, like a ramfs mount

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2010-04-27 01:22:54     Re: How to handle few rw files using cramfs

Jayaprabhu Nadarajan (INDIA)

Message: 88930   

Thanks Mike.

How to identify the list of files that need to be in rw mode by User Application and by Kernel ?

Regards,

Jp

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2010-04-27 01:28:47     Re: How to handle few rw files using cramfs

Mike Frysinger (UNITED STATES)

Message: 88932   

there really arent any files that need to be rw except /var which is why the default rc mounts that as ramfs

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2010-04-27 10:54:54     Re: How to handle few rw files using cramfs

Jayaprabhu Nadarajan (INDIA)

Message: 88964   

Hi Mike,

Our application involves lot of configuration files inside etc folder to be modified at run time so i have made changes in rc file as follows

.........

mount -t ramfs var /var

mkdir /var/tmp /var/log /var/run /var/lock

cp -a etc/ var/

cd var/

mount -t ramfs etc/ etc/

cd

..........

I am not sure whether this is the right way to do (without symlinks). So please suggest.

Regards,

Jp

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2010-04-27 12:21:01     Re: How to handle few rw files using cramfs

Mike Frysinger (UNITED STATES)

Message: 88967   

how you configure your /etc is up to you.  there are no hard requirements in the dist in that regard.