Re: [PATCH] scripts: prune-kernel:remove old kernels and modules dir from system

From: Bhaskar Chowdhury
Date: Thu Oct 31 2019 - 00:53:26 EST


Thank you so much Randy. I am awfully sorry about the ugly code ,
hopefully come up with a better one. If I understood your expectation.

I know we all are blessed with limited resources like patience.Thanks
for holding this long...little more and we will be over it.

:)

On 21:32 Wed 30 Oct 2019, Randy Dunlap wrote:
On 10/30/19 8:37 PM, Bhaskar Chowdhury wrote:
Thank you Randy, my response are inline. Please look at it.I am
wondering , what else I could do get this damn! thing going??
Any clue??

On 19:33 Wed 30 Oct 2019, Randy Dunlap wrote:
Hi,

On 10/30/19 2:54 AM, Bhaskar Chowdhury wrote:
This patch will remove old kernels and modules directorey related
to that kernel from the system by interactively and silently.Here
are few interactions with the scripts

1)

â ~/git-linux/linux-kbuild [master|AM 1/1 âÂ59|â]
14:52 $ ./scripts/prune-kernel -h
Usage: prune-kernel [ri]

Â-r | --remove kernel_ver modules_dir_name

 -i | --interactive use as interactive way
 â-1 ~/git-linux/linux-kbuild [master|AM 1/1 âÂ59|â]
  14:52 $ ./scripts/prune-kernel --help
 Usage: prune-kernel [ri]

That "[ri]" is confusing to me.
This are the options one has to pass with the script.Like below:

I know that. But it's missing '-', so it looks like
$ prune-kernel r 5.2.5-foobar

would work.

Will correct that.

ÂÂ -r | --remove kernel_ver modules_dir_na]

ÂÂÂ -i | --interactive use as interactive way
ÂÂ Â2)

Ââ-1 ~/git-linux/linux-kbuild [master|AM 1/1 âÂ59|â]
Â14:52 $ ./scripts/prune-kernel -r 5.3.3
ÂYou need to provide kernel version and modules dir name
Â
Ââ-1 ~/git-linux/linux-kbuild [master|AM 1/1 âÂ59|â]
Â14:53 $ ./scripts/prune-kernel -r
ÂYou need to provide kernel version and modules dir name
Â
Ââ-1 ~/git-linux/linux-kbuild [master|AM 1/1 âÂ59|â]
Â14:54 $ ./scripts/prune-kernel -r 5.3.3 5.3.3-foo

This one above didn't remove any kernel files.
Needs more testing.
It does remove but silently, as you and Bruce asked for this feature.

No, see the code below for -r...

Okay ...look like some some uniformity missing
3)

$ ./scripts/prune-kernel --remove
You need to provide kernel version and modules dir name

â-1 ~/git-linux/linux-kbuild [master|AM 1/1 âÂ59|â]
14:55 $ ./scripts/prune-kernel --remove 5.3.3
You need to provide kernel version and modules dir name

â-1 ~/git-linux/linux-kbuild [master|AM 1/1 âÂ59|â]
14:55 $ ./scripts/prune-kernel --remove 5.3.3 5.3.3-foo


4)14:55 $ ./scripts/prune-kernel -i

Enter kernel version to remove or blank/empty to exit:


5)14:57 $ ./scripts/prune-kernel --interactive

Enter kernel version to remove or blank/empty to exit:
â ~/git-linux/linux-kbuild [master|AM 1/1 âÂ59|â]


6)14:59 $ ./scripts/prune-kernel --interactive

Enter kernel version to remove or blank/empty to exit:5.3.3
Please give the full modules directory name to remove:5.3.3-foo



Removed kernel version:5.3.3 and associated modules:5.3.3-foo ...Done.


7)15:00 $ ./scripts/prune-kernel -i

Enter kernel version to remove or blank/empty to exit:5.3.3
Please give the full modules directory name to remove:5.3.3-foo



Removed kernel version:5.3.3 and associated modules:5.3.3-foo ...Done.


Signed-off-by: Bhaskar Chowdhury <unixbhaskar@xxxxxxxxx>
---
Âscripts/prune-kernel | 63 ++++++++++++++++++++++++++++++++++++++++++++
Â1 file changed, 63 insertions(+)

diff --git a/scripts/prune-kernel b/scripts/prune-kernel
index a25aa2160d47..a91010d0e2af 100755
--- a/scripts/prune-kernel
+++ b/scripts/prune-kernel
@@ -1,3 +1,66 @@
Â#!/bin/bash
Â# SPDX-License-Identifier: GPL-2.0
+#This script will delete old kernels and modules directory related to it
+#-h with the script will show you the help
+#-r with the script take two parameter: kernel_ver and modules_dir_name
+#-i with the script allow you do the removing interactive way

+flag=$1
+kernel_ver=$2
+modules_dir_name=$3
+boot_dir=/boot
+modules_dir=/lib/modules
+
+remove_old_kernel() {
+ÂÂÂ cd $boot_dir
+ÂÂÂ rm -If vmlinuz-$kernel_version System.map-$kernel_version config-$kernel_version
+ÂÂÂ return 0
+}
+
+remove_old_modules_dir() {
+ÂÂÂ cd $modules_dir
+ÂÂÂ rm -rf $modules_version
+ÂÂÂ return 0
+}
+
+usage() {
+ÂÂÂ printf "Usage: $(basename $0) [ri] \n"
+ÂÂÂ printf "\n -r | --remove kernel_ver modules_dir_name \n"
+ÂÂÂ printf "\n -i | --interactive use as interactive way \n"
+}
+
+for arg in "$@"

what is the purpose (use) of "arg" here?

This variable is used in case statement below.

I can't find any use of 'arg' anywhere else in the script.
Please show me where it is.
My bad and apologies for overlooking.

what is the purpose of the for loop?

It scan through all the parameters pass .

What is this script supposed (expected) to do with multiple arg parameters?

It uses multiple parameter
Is any 'shift' needed to consume (or discard) the first 3 positional
command line arguments?
Nope, that is not required. And I haven't use any.

+do
+ÂÂÂ case "$flag" in
+ÂÂÂÂÂÂÂ -i | --interactive)
+ÂÂÂÂÂÂÂÂÂÂÂ printf "\nEnter kernel version to remove or blank/empty to exit:%s"
+ÂÂÂÂÂÂÂÂÂÂÂ read kernel_version
+ÂÂÂÂÂÂÂÂÂÂÂ if [[ $kernel_version != "" ]]; then
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ remove_old_kernel
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ printf "Please give the full modules directory name to remove:%s"
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ read modules_version
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ if [[ $modules_version != "" ]]; then
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ remove_old_modules_dir
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ printf "\n\n\n Removed kernel version:$kernel_version and associated modules:$modules_version ...Done. \n"

This message is only printed if $modules_version is non-empty. If it is empty,
remove_old_kernel() has silently removed some kernel files (if they existed).
it will fail to remove anything if the kernel_version or modules_version
are empty and importantly exit.

+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ else
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ exit 1
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ fi
+ÂÂÂÂÂÂÂÂÂÂÂ fi
+ÂÂÂÂÂÂÂÂÂÂÂ ;;
+ÂÂÂÂÂÂÂ -h | --help)
+ÂÂÂÂÂÂÂÂÂÂÂ usage
+ÂÂÂÂÂÂÂÂÂÂÂ exit 1
+ÂÂÂÂÂÂÂÂÂÂÂ ;;
+ÂÂÂÂÂÂÂ -r | --remove)
+ÂÂÂÂÂÂÂÂÂÂÂ if [[ $# -ne 3 ]]; then
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ printf "You need to provide kernel version and modules dir name\n"
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ exit 1
+ÂÂÂÂÂÂÂÂÂÂÂ else
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ cd $boot_dir
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ rm -f $kernel_ver

That 'rm' doesn't remove any files. Compare what remove_old_kernel() does.
No,it is not using that function rather take the parameter from the
commandline and get into boot dir match with it and remove it.

But it doesn't do that. I tested it. It should be more like what
rmeove_old_kernel() does:

rm -If vmlinuz-$kernel_ver System.map-$kernel_ver config-$kernel_ver

and if not, please explain why not.
Okay, again some uniformity missing in the code, I would like to your
suggested method,i.e call remove_old_kernel to do the job instead of depending on individual kernel.


+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ cd $modules_dir
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ rm -rf $modules_dir_name
+ÂÂÂÂÂÂÂÂÂÂÂ fi
+ÂÂÂÂÂÂÂÂÂÂÂ ;;
+ÂÂÂ esac
+done
--

The script, after this patch is applied, still contains the old script's for-loop
at the end of the "new" prune-kernel script.

Amazing! now it needs some explanation how I did...you probably want
that ..here are the steps....
1)fetch that prune-kernel file from repos , which contains Bruce's code
in it.
2) get inot it by editior, remove all except first two lines i.e bash
interpreter and PSDX .
3)Save and commit it locally.
4) Write my own code
5) save it and commit it locally.
6) go one level up use checkpatch to see anything bad creeps in
7) Fixed the damn things if it reports.
8) create the patch
9) test it
10) Send it.

Now, how the heck , that for loop is getting staying there is a mystry
to me!! Look like that is ruin all the work.
irk...

I don't know. I just know that it's not working AFAICT.
Thank you, will be more vigilant in next iteration.

--
~Randy

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