AU: Catch terminate signals and block exit if necessary.

AU: Catch terminate signals and block exit if necessary.

Adds a global Terminator class to manage signals and exit blocking.

BUG=7392
TEST=unit tests, gmerged on device, initctl stop update-engine

Change-Id: I2291d4eb55240a6662b18ff834af161d957bce2f

Committed: http://chrome-svn/viewvc/chromeos?view=rev&revision=9c0baf8

[adlr, 2010-10-07 17:26:05]

LGTM nice!

http://codereview.chromium.org/3608015/diff/2001/3005
File terminator.cc (right):

http://codereview.chromium.org/3608015/diff/2001/3005#newcode1
terminator.cc:1: // Copyright (c) 2010 The Chromium OS Authors. All rights
reserved.
it might be a bit more efficient to have the OS kill our process if we aren't
blocking exit, rather than handling the signal and then calling exit. On the
other hand, by always calling exit(), we are more consistent in how we exit,
since exit() calls global dtors, atexit() stuff, etc.

I think the code is fine, just wanted to mention it.

[petkov, 2010-10-07 17:29:31]

Thanks for the quick review.

http://codereview.chromium.org/3608015/diff/2001/3005
File terminator.cc (right):

http://codereview.chromium.org/3608015/diff/2001/3005#newcode1
terminator.cc:1: // Copyright (c) 2010 The Chromium OS Authors. All rights
reserved.
On 2010/10/07 17:26:05, adlr wrote:
> it might be a bit more efficient to have the OS kill our process if we aren't
> blocking exit, rather than handling the signal and then calling exit. On the
> other hand, by always calling exit(), we are more consistent in how we exit,
> since exit() calls global dtors, atexit() stuff, etc.
> 
> I think the code is fine, just wanted to mention it.

Yeah, thought about this. It seems better to exit cleanly by explicitly calling
exit. We can also exit glib loops, etc. if necessary. Also, we currently catch
only TERM signals. KILL will kill us directly.

I'll leave it as is.