Resume boot script fix makes /bin/resume unnecessary (kernel's internal swsusp)

New script for /usr/share/initramfs-tools/scripts/local-premount/resume
attached (full).
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Updated script: Please discard the previous patch in post #1 and the
full script file in post #2. Instead, use the patch in this post, or the
full script in a following post. This should be good for testing.

[Although the previous version of the script worked in all my tests,
it has a bug which can make it fail if there are symlinks to symlinks.
Also the code is cleaned up: Finding the major:minor numbers
for the device is now done using the busybox builtins stat/printf
instead of chasing through sysfs or /proc/partitions. This makes
it even more close to the original klibc/kinit C program resumelib.c.]
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Updated full script : This post contains the updated version of full resume script.

Please discard the version in post #2 and use this one instead for testing.
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Further Update: Not a bug fix, but more code cleanup (the diff is
shorter) making the checking logic identical to that of the original
resumelib.c.

This post contains the diff, and the full script in the following post.
This version should be preferred over the one in post #4/#5.
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Full script, with the patch of post #6 applied, ready for testing.

Latest patch (one more version -- delaying stat call to make sure disk is ready).

And the latest full script file.

Frozen version : This is frozen until bugs are found. (This post contains
the patch and the next post the full script.)

Boot script: scripts/local-premount/resume

Summary of changes from current initramfs-tools production version:

- /bin/resume is not used any more and its function of echoing
  major:minor on to /sys/power/resume is done in the script itself

- The major and minor device number is found using the stat built-in
  of busybox

- The check logic is identical to that of original /bin/resume (which
  means not only block but also character special files are allowed!)

- Device TYPE detection method: Tries blkid first for RESUMEDELAY
  seconds, and if that fails then falls back to the original behaviour of
  calling wait-for-root with a wait value of RESUMEDELAY seconds
.

Full script --- frozen version.

Status changed to 'Confirmed' because the bug affects multiple users.