Don't convert partuuids for nonexistent source partitions

[aaronkollasch]

Copying this issue from billw2#149 as that repo is abandoned.

Issue

When converting to partuuids, if there is an empty element in ${src_partition[@]}, then /etc/fstab will have /dev/ replaced with PARTUUID= without actually changing the device name to a PARTUUID.

I don't have the exact logs when this happened to me, but it looked something like this:

$ sudo rpi-clone -l sda --convert-fstab-to-partuuid

This will change your /etc/fstab, are you sure?  (yes/no): yes

Converting /etc/fstab from device names to PARTUUID
lsblk: /dev/: not a block device
  Editing /etc/fstab, changing /dev/ to
...

and I ended up with a broken fstab:

proc            /proc           proc    defaults          0       0
PARTUUID=mmcblk0p6  /boot           vfat    defaults          0       2
PARTUUID=mmcblk0p7  /               ext4    defaults,noatime  0       1
# a swapfile is not a swap partition, no line here
#   use  dphys-swapfile swap[on|off]  for that

I had previously run sudo rpi-clone -l sda so perhaps that is why there was an empty element in src_partition, I'm not sure.

Changes

Check that ${src_partition[p]} is not empty before editing /etc/fstab.

Then, the command I used will instead exit with an error, which is much safer:

Could not find any sda partition names in /etc/fstab, nothing changed.

[geerlingguy]

Since I don't personally use this feature, if someone else can give the thumbs up on the change, I'd be happy to merge!

[framps]

Wouldn't it make sense to make sure there is no empty element in src_partition? Would be interesting to know you partitioning which causes this issue 😉

[aaronkollasch]

Wouldn't it make sense to make sure there is no empty element in src_partition? Would be interesting to know you partitioning which causes this issue 😉

My disk has primary partitions sda1 and sda2, and then logical partitions sda5+, so there will be indices in between without partitions, whereas the code iterates through indices 1-n. If you look at where src_partition is created, there is actually a check for empty lines:

rpi-clone/rpi-clone

Lines 677 to 694 in 423470c

	for ((p = 1; p <= n_src_parts; p++))
	do
	line=$(echo "$src_partition_table" | grep -e "^${p}:")
	if [ "$line" == "" ]
	then
	src_exists[p]=0
	continue
	fi
	src_exists[p]=1
	if ((p == root_part_num))
	then
	src_partition[p]=${src_root_dev#/dev/}
	src_device[p]=$src_root_dev
	else
	src_partition[p]="${src_part_base}${p}"
	src_device[p]="/dev/${src_partition[p]}"
	fi

and there's also a check later on in the main code path:

rpi-clone/rpi-clone

Lines 1001 to 1006 in 423470c

	for ((p = 1; p <= n_src_parts; p++))
	do
	if ((!src_exists[p]))
	then
	continue
	fi

But it doesn't seem to have made it to the part where partuuids get converted:

rpi-clone/rpi-clone

Lines 958 to 967 in 423470c

	for ((p = 1; p <= n_src_parts; p++))
	do
	if grep -q "^/dev/${src_partition[p]}" $fstab_tmp
	then
	partuuid=$(lsblk -n -o PARTUUID /dev/${src_partition[p]})
	sed -i "s/\/dev\/${src_partition[p]}/PARTUUID=$partuuid/" $fstab_tmp
	printf " Editing $fstab, changing /dev/${src_partition[p]} to $partuuid\n"
	((++count))
	fi
	done

(actually I might change my code to match L1003-L1006 and check src_exists[p])

[framps]

I didn't detect Bill already used an array to mark a partition as not to exist :-(. Frankly I would just delete this partition in the list instead of mark it as non existing. But then you can't use a simple array with partition indices any more and will need much more complicated logic :-(

I agree to use src_exists[p] is a much more clean way to handle this exception.

[framps]

LGTM 👍