Add a hack to deal with needing to spawn pulseaudio, and deal with the changes HOME of chronos.

Add a hack to deal with needing to spawn pulseaudio, and deal with the changes HOME of chronos.

The volume key events need to modify the pulseaudio daemon for the chronos
user. For amixer to identify the right daemon, it needs to run a chronos,
and it needs to know where ~/.pulse is.  The "su" handles changing users,
however, depending on what stage you are in login, ${HOME} changes values.

The only other processes that talk to pulseaudio currently happen inside UI
session, where HOME has been overridden to be /home/chronos/user.  We
normalize on this value of HOME to avoid starting 2 unrelated daemons.

BUG=1720

[awong, 2010-03-02 03:19:23]

This is a hack, but it works for now I think.

[Chris Masone, 2010-03-02 05:25:27]

http://codereview.chromium.org/661352/diff/1/2
File src/platform/acpi/action_hotkey.sh (right):

http://codereview.chromium.org/661352/diff/1/2#newcode15
src/platform/acpi/action_hotkey.sh:15: su chronos -c "HOME=/home/chronos/user
amixer set Master toggle"
why aren't you using minijail?  And why not set HOME once, outside this case
statement?  We use this pattern all over the upstart jobs that run many system
services (windowmanager, screen-locker, etc)

[awong, 2010-03-02 06:14:22]

http://codereview.chromium.org/661352/diff/1/2
File src/platform/acpi/action_hotkey.sh (right):

http://codereview.chromium.org/661352/diff/1/2#newcode15
src/platform/acpi/action_hotkey.sh:15: su chronos -c "HOME=/home/chronos/user
amixer set Master toggle"
On 2010/03/02 05:25:27, cmasone wrote:
> why aren't you using minijail?  And why not set HOME once, outside this case
> statement?  We use this pattern all over the upstart jobs that run many system
> services (windowmanager, screen-locker, etc)

Since this isn't an upstart job, I wasn't sure if I could still use minijail. 
Though, thinking back on it, I can't think of a reason why that was a valid
worry.  I'll modify the CL to do that tomorrow morning.

As for setting home outside of the su statement, I thought su scrubbed the
environment so it wouldn't be preserved.

[awong, 2010-03-02 18:14:59]

Here's a new version using minijail.

On 2010/03/02 06:14:22, awong wrote:
> http://codereview.chromium.org/661352/diff/1/2
> File src/platform/acpi/action_hotkey.sh (right):
> 
> http://codereview.chromium.org/661352/diff/1/2#newcode15
> src/platform/acpi/action_hotkey.sh:15: su chronos -c "HOME=/home/chronos/user
> amixer set Master toggle"
> On 2010/03/02 05:25:27, cmasone wrote:
> > why aren't you using minijail?  And why not set HOME once, outside this case
> > statement?  We use this pattern all over the upstart jobs that run many
system
> > services (windowmanager, screen-locker, etc)
> 
> Since this isn't an upstart job, I wasn't sure if I could still use minijail. 
> Though, thinking back on it, I can't think of a reason why that was a valid
> worry.  I'll modify the CL to do that tomorrow morning.
> 
> As for setting home outside of the su statement, I thought su scrubbed the
> environment so it wouldn't be preserved.

[Chris Masone, 2010-03-02 18:24:40]

lgtm

thanks for making the changes!