gui/install.sh: add www-data to "sudo" group

[EricClaeys]

so it can execute the vcgencmd command (new "show throttling" view on the "System" page).
There is a separate PR for the allsky-portal portion of this change.

[linuxkidd]

Actually, can we not just add the specific command to /etc/sudoers.d/allsky (populated from here), instead of giving full sudo access to www-data ?

[EricClaeys]

@linuxkidd, I tried that on my Pi and it didn't work, even after a reboot. If you can get it to work with the file, I prefer that way.
Here's what I added to /etc/sudoers.d/allsky:

www-data ALL=(ALL) NOPASSWD:/usr/bin/vcgencmd get_throttled
www-data ALL=(ALL) NOPASSWD:/opt/vc/bin/vcgencmd get_throttled
www-data ALL=(ALL) NOPASSWD:/usr/bin/vcgencmd
www-data ALL=(ALL) NOPASSWD:/opt/vc/bin/vcgencmd

As you can see, I even tried the file the symbolic link pointed to.

[linuxkidd]

@EricClaeys I added only the last line to my /etc/sudoers.d/allsky file, and it worked for me:

www-data ALL=(ALL) NOPASSWD:/opt/vc/bin/vcgencmd

[EricClaeys]

@linuxkidd did you have to execute anything so the file would be re-read?

[linuxkidd]

Na, nothing extra needed. The file is re-read on each sudo attempt, so modifying, and saving is sufficient. I used the system.php file from your portal PR.

[EricClaeys]

Thanks Michael. I added the one-line change to the "allsky" sudoers file and got rid of the addition to install.sh.