Add read only flag to mount_gpt_image

Add read only flag to mount_gpt_image

Change-Id: I33ea8b2148a3e49a6c5de25f2957306130ff092e

BUG=
TEST=Ran and verified with and without flag.  Checked mount and tried writing
file to rootfs (to verify it was ro).  Also re-ran cros_make_image_bootable
to make sure it worked fine after changes.

Committed: http://chrome-svn/viewvc/chromeos?view=rev&revision=e7f1a2b

[sosa, 2010-09-22 23:02:27]

Give an option to mount_gpt_image to allow it to completely mount the image ro. 
This allows us to mount the image cleanly and look around without having to
re-generate hashes with cros_mark_image_bootable.

[Will Drewry, 2010-09-23 02:33:31]

one quick question but seems fine otherwise

http://codereview.chromium.org/3479007/diff/2001/3001
File mount_gpt_image.sh (right):

http://codereview.chromium.org/3479007/diff/2001/3001#newcode50
mount_gpt_image.sh:50: if eval "mount | grep \"${FLAGS_rootfs_mountpt}
\(rw,bind\)\""; then
why eval? and not mount | grep -q "..."?

Also is this here just in case of a rw remount or could you just check
FLAGS_read_only?

[sosa, 2010-09-28 20:06:27]

http://codereview.chromium.org/3479007/diff/2001/3001
File mount_gpt_image.sh (right):

http://codereview.chromium.org/3479007/diff/2001/3001#newcode50
mount_gpt_image.sh:50: if eval "mount | grep \"${FLAGS_rootfs_mountpt}
\(rw,bind\)\""; then
Had issues without eval before realizing it was another bug I had fixed. 
Removed eval.

I do this because I don't want to depend on someone setting the right flag for
unmount since it's easy to infer from the mount table i.e.

./mount_gpt_image -m --read_only
./mount_gpt_image -u

Should just work fine.

On 2010/09/23 02:33:31, Will Drewry wrote:
> why eval? and not mount | grep -q "..."?
> 
> Also is this here just in case of a rw remount or could you just check
> FLAGS_read_only?

[sosa, 2010-09-29 00:31:35]

ping?

[Will Drewry, 2010-09-29 00:40:17]

LGTM

You might want to do a full build_image and a mod_image_for_[something] and
makes sure it all goes through, but the change looks fine.