How to correctly fix init.resizefs when booting rpi from ssd

[Ognian]

When generating the image for raspberry pi and burning it to a ssd, so that the rpi boots from the usb disk instead of the sd card
everything it needs to be changed is this line ('p1' to '1') to make the install successful.
I'm not sure how we shall fix this. One possibility is to add a third '$IMAGE_TYPE' -> raspberrypiusb but this would lead to many changes in the if's which would make the code less readable. Another would be to add a '$IMAGE_SUBTYPE'...
The most elegant way would be to somehow programmatically find out the name of the first partition of the '$ROOTDISK'...
Any ideas ?

[Ognian]

Added Ognian@e562ca5 but it is not tested yet... (don't have empty sd and/or usb ssd's now)

[sgielen]

I think programmatically finding out the name of the first partition should be feasible. I guess the name of the disk is quite unpredictable and can also change in the future, so I would prefer not to hardcode any expectations of it. In that sense, I'd also like to get rid of this hardcoding of the expected name of the first partition that we have now.

Tools like lsblk are able to find out a partition tree from a block device, perhaps using /sys or /proc, I think it would be a good idea to find out how they do it, and use similar behaviour here.

[Ognian]

Changed to Ognian@23ede0c should work but is still not tested...

[cwoolum]

I was able to test this. The first commit does work. The second one has the following error:

lsblk: error while loading shared libraries: libmount.so.1: cannot open shared object file: No such file or directory
mount: can't read '/etc/fstab': No such file or directory

[cwoolum]

I tried flashing a regular SD Card again afterward and failed due to the regex not matching. Since we're using sh instead of bash, the syntax needs to be a bit different.

if echo "$ROOTDISK" | grep -Eq $MMCROOT_REGEX; then

[sgielen]

Just pushed as b3ed5f1, thank you @Ognian and @cwoolum :-)