Get raw battery max and current capacity on macOS

[artemist-work]

Apple's x86 laptops report battery status in mAh but its ARM laptops use percent.
This commit uses an undocumented raw capacity field which reports mAh on both x86 and ARM laptops. I've tested on a 2022 M2 MacBook Pro and a 2012 i5 MacBook Pro, both running macOS 12. However, this needs more testing on more systems.

This will partially fix #6800 but will not fix the incorrect health column. I've spent a while trying to figure out how the Battery.prefPane and coconutBattery get correct results but so far I've only found that Battery.prefPane uses IOPSCopyPowerSourcesByType(1) then gets the Battery Service State field from the first battery, which does not exist for me

[linux-foundation-easycla]

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• ✅ login: artemist-work / name: Artemis Tosini (1e91b26)

[directionless]

This commit uses an undocumented raw capacity field which reports mAh on both x86 and ARM laptops. I've tested on a 2022 M2 MacBook Pro and a 2012 i5 MacBook Pro, both running macOS 12. However, this needs more testing on more systems.

You mention undocumented. Do you think it's going to stick around?

[zwass]

Can confirm I get the exact same results before/after change on 2020 Intel MBP running 12.5.

Can confirm the change provides numbers that appear to be mAh on M1 running 13 beta 3.

[zwass]

Do you think it's going to stick around?

I'm not sure what basis we would have to make such a determination... Osquery does use tons of undocumented and private APIs to get at the data we provide, so it seems reasonable enough to me to do so here.

[directionless]

Okay, I'm game

[directionless]

I guess the other question is whether we should expose both.

[zwass]

I'd say leave it as-is? The percentage can be calculated from these values in both cases.

[mike-myers-tob]

I've tested this PR using select * from battery; successfully on:

• MacBook Pro 2020 (x86), macOS 12.5. "Designed capacity" for this battery is not published by Apple anywhere I can find, but unofficially it is 5,086 mAh which is what osquery now outputs with this PR.
• Mac Mini M1, macOS 12.5. No battery. The table reports nothing (no rows), as before.