Go to file

hygienic-books 3efdf550f9 fix(script): Trigger restart only on FDs for binaries (#3 )

Rename variable and its echo output headline to something that
implies we're talking about binaries specifically, not all files.

Also add an awk condition that only outputs an lsof line if lsof
showed a file descriptor to a path somewhere in a /bin/ or /sbin/
directory. As a good enough approximation this will help us trigger a
system reboot when something in /usr/bin/foo or /usr/local/sbin/bar
was deleted while at the same time vastly reducing the amount of
unnecessary system reboots for random /memfd anonymous files and
shared memory objects in /dev/shm.

An awk program has multiple repetitions of 'condition { action }'
where the action is literally written inside curly braces.

Replace the pseudo-condition '1' (i.e. something that is always
truthy) with '$(NF-1) ~ /\/s?bin\//'.

To break it down the new condition is:

  - If the second to last field in a line ...
    $(NF-1)

  - Matches an expression ...
    $(NF-1) ~ /expression/

  - That is /s?bin/ ...
    /s?bin/

Then we want to do '{ action }' which will still print affected file
descriptors as before. An awk expression is encapsulated in a slash
pair like so: '/expression/'. We want to search for any string that
contains literal slashes like so: '/s?bin/'. We unfortunately have
to escape the slashes we want to find to make sure awk doesn't treat
them as the end of its awk expression string:

                      +------+------ Backslash-escape here
                      v      v
  - Right: $(NF-1) ~ /\/s?bin\//
  - Wrong: $(NF-1) ~ //s?bin//

The expression 's?' is probably self-explanatory. An awk expression
is related to a regular expression but not identical to it. Still, a
question mark means the same thing as in a PERL-compatible regular
expression, the preceding character is optional: we want either one
of '/sbin/' or '/bin/'.

2024-06-19 20:16:37 +02:00

.gitignore

feat(meta): Add .gitignore (#1 )

2024-06-07 17:32:39 +02:00

arch-needs-restart.hook

feat(script): Initial commit

2023-03-19 21:35:59 +01:00

arch-needs-restart.sh

fix(script): Trigger restart only on FDs for binaries (#3 )

2024-06-19 20:16:37 +02:00

LICENSE

Initial commit

2023-03-19 20:16:12 +00:00

README.md

docs(script): Fix script name

2023-03-19 21:37:03 +01:00

README.md

arch-needs-restart

A helper script to check which updated libraries and kernel are in use and require a restart

Setup

Get started like so:

Clone repo into arbitrary path <repo>
Make arch-needs-restart.sh executable
```
chmod +x <repo>/arch-needs-restart.sh
```
Symlink to files, for example
```
sudo ln -s <repo>/arch-needs-restart.sh /usr/local/bin/arch-needs-restart
sudo ln -s <repo>/arch-needs-restart.hook /usr/share/libalpm/hooks/arch-needs-restart.hook
```
Note that while you may choose arbitrary locations for symlinks arch-needs-restart.hook references /usr/local/bin/arch-needs-restart. Change that accordingly if you need to.

Credits

StackExchange user Christian Zangl aka laktak in January 2021 post unix.stackexchange.com/a/630982