fix(dmsquash-live): handle relative pathspec

[LaszloGombos]

This change is required to make the following canonical example work that is mentioned in the documentation:

rd.live.overlay=/dev/sdb1:persistent-overlay.img

This example has been in the dracut documentation since 2015.

At the same time, improve the documentation with a more specific example.

Checklist

• I have tested it locally
• I have reviewed and updated any documentation if relevant
• I am providing new code and test(s) for it

Fixes #579 (partially)

CC @FGrose @Conan-Kudo @fabiand

[aafeijoo-suse]

This change is required to make the following canonical example work that is mentioned in the documentation

Are we sure that the example in the man page (pathspec not starting with / ) is correct?

If the answer is yes, wouldn't it be easier to just fix when pathspec is assigned and doesn't start with / , to avoid the "//" case?

dracut/modules.d/90dmsquash-live/dmsquash-live-root.sh

Line 140 in aca5120

pathspec=${overlay##*:}

[LaszloGombos]

Are we sure that the example in the man page (pathspec not starting with / ) is correct?

I think the example in the documentation can be improved. I added the improvement in the doc to this PR as well.

Regardless this example has been in the documentation for 7 years, and maintaining compatibility with this example seems to be simple enough.

If the answer is yes, wouldn't it be easier to just fix when pathspec is assigned and doesn't start with / , to avoid the "//" case?

Thanks for this, great catch. I made the change.

[aafeijoo-suse]

Are we sure that the example in the man page (pathspec not starting with / ) is correct?

I think the example in the documentation can be improve. I added the improvement in the doc to this PR as well.

Regardless this example has been in the documentation for 7 years, and maintaining compatibility with this example seems to be simple enough.

What I meant was I haven't found any example of pathspec without starting with /, because it refers to a file path.

[stale]

This issue is being marked as stale because it has not had any recent activity. It will be closed if no further activity occurs. If this is still an issue in the latest release of Dracut and you would like to keep it open please comment on this issue within the next 7 days. Thank you for your contributions.

[stale]

This issue is being marked as stale because it has not had any recent activity. It will be closed if no further activity occurs. If this is still an issue in the latest release of Dracut and you would like to keep it open please comment on this issue within the next 7 days. Thank you for your contributions.