1417823 - about:networking#logging cannot log GMP Child Process on Mac and Windows.

Status: RESOLVED DUPLICATE of bug 1344778

(Core :: XPCOM, enhancement)

Description

[James Cheng[:JamesCheng]]

We might ask for users using about:networking#logging to log our GMP logs for us.

But I tested Linux, Mac, Windows with about:networking#logging, the behaviors are not the same.

Linux works well without any preference change.

On Mac and Windows,

I changed

security.sandbox.logging.enabled to true
security.sandbox.content.level to 0
and start logging by about:networking#logging

I play
https://shaka-player-demo.appspot.com/demo/#asset=//demo.unified-streaming.com/video/tears-of-steel/tears-of-steel-dash-widevine.ism/.mpd;lang=zh-TW

I can get 
ChromiumCDMParent log which is running in Content Process 

But I cannot get any
ChromiumCDMChild[1] log which is running in GMP Process 

The log-txt-child.pid has generated without any GMP Child log.

Did I miss any settings or preferences?

[1]
https://searchfox.org/mozilla-central/rev/550148ab69b2879bfb82ffa698720ede1fa626f2/dom/media/gmp/ChromiumCDMChild.cpp#26

Comment 1

[James Cheng[:JamesCheng]]

Hi bobowen,

Do you know who can help me to know if this is the limitation or any platform-specific preference that I should set?

Thanks.

Comment 2

[Gary Chen [:xeonchen]]

It's actually MOZ_LOG, I don't think the component is Networking.

Comment 3

[James Cheng[:JamesCheng]]

I just fork form Bug 1344778 which is Networking.

Comment 4

[Bob Owen (:bobowen)]

(In reply to James Cheng[:JamesCheng] from comment #1)
> Hi bobowen,
> 
> Do you know who can help me to know if this is the limitation or any
> platform-specific preference that I should set?
> 
> Thanks.

The dynamic logging in about:networking has never worked in the sandboxed child processes.

Those two prefs won't make any differences, security.sandbox.logging.enabled controls logging to do with the sandboxing itself, security.sandbox.content.level will affect the sandboxing on the content process not GMP.

At the moment you would need to use the MOZ_LOG, MOZ_LOG_FILE environment variables, before starting Firefox.

I don't think that this bug adds anything over bug 1344778.
(Fixing bug 1344778, before starting the child process ought to be fairly straight forward, enabling for an already running process will be a trickier.)

Comment 5

[Shih-Chiang Chien [:schien] (UTC+8) (use ni? plz)]

Core::XPCOM might be better and @froydnj might have some insight to this bug.

Comment 6

[Nathan Froyd [:froydnj]]

(In reply to Shih-Chiang Chien [:schien] (UTC+8) (use ni? plz) from comment #5)
> Core::XPCOM might be better and @froydnj might have some insight to this bug.

Bob has already had more insight in comment 4 than I would be able to offer. :)