Shortcircuit commands with version or help flags

[dereknola]

Proposed Changes

Before attempting to open config files, we check if the arguments provided contain a --version, -v, --help, -h flag. If so, we shortcircuit the search. As -h and -v flags always override the given command anyway, this enables users who do not have permission to access /etc/rancher/k3s/config.yaml or other root guarded files to still run these basic commands.

Types of Changes

Verification

1. Create a config file: touch /etc/rancher/k3s/config.yaml
2. Change the permissions so only root can read it: sudo chmod 700 /etc/rancher/k3s/config.yaml
3. Call k3s --help, k3s --version, k3s -h, k3s server -h. Note that these commands now complete successfully.

Testing

Linked Issues

#4321

User-Facing Change

Non root users can now call `k3s --help` and `k3s --version` commands without running into permission errors over the default config file.

Further Comments

This change is injected into FindString because this function is called when attemtping to find data-dir or prefer-bundled-bin arguments before running a command. FindString in turn attempts to open the default config file (/etc/rancher/k3s/config.yaml), and if permission is not given on that file, the whole process will fail.

[codecov]

Codecov Report

Patch coverage: 42.85% and project coverage change: +4.35 🎉

Comparison is base (e5e1a67) 47.55% compared to head (c4df6fb) 51.91%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #7683      +/-   ##
==========================================
+ Coverage   47.55%   51.91%   +4.35%     
==========================================
  Files         141      141              
  Lines       14347    14358      +11     
==========================================
+ Hits         6823     7454     +631     
+ Misses       6442     5728     -714     
- Partials     1082     1176      +94     

Flag	Coverage Δ
e2etests	48.02% <10.00%> (?)
inttests	44.88% <7.14%> (-0.05%)	⬇️
unittests	19.90% <42.85%> (+0.03%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
pkg/configfilearg/defaultparser.go	17.64% <0.00%> (+0.98%)	⬆️
pkg/configfilearg/parser.go	72.88% <46.15%> (-1.68%)	⬇️

... and 41 files with indirect coverage changes

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