On 01/28/2013 03:39 PM, Brian Smith wrote:
Hi all,
After seeing many, many bugs about difficulty of writing code that properly
handles NSS shutdown during XPCOM profile teardown, I think the only reasonable
way forward is to simply make it so that NSS never shuts down--including in
debug builds.
This will greatly simplify lots of code--not just code in security/manager, but
also code in WebRTC, DOM (DOMCrypt), Toolkit (toolkit/identity), and Necko
(netwerk/). We already have a significant amount of code that is already
running in Firefox every day, but which doesn't handle NSS shutdown correctly.
Changing PSM so that NSS never shuts down is an easy thing for me to do. But it
would have the following negative implications:
1. If we don't We will need to mask out lots of memory leaks in
memleak-reporting builds, because we'll have a lot of memory allocated that
would only get freed during NSS_Shutdown.
This is probably the biggest downside. It may be hard to identify NSS
object reference leaks as well).
2. Because NSS reads and writes to files in the profile directory, the profile
directory must be readable and writable up until process exit. The current
rules for XPCOM shutdown say that services must stop doing disk I/O well before
then; we would need to change the rules. It is safe to do so?
3. Some buggy PKCS#11 modules (such as smart card readers) may need to be updated to
support this. (A PKCS#11 module should gracefully handle the process exiting without
"proper" shutdown, because it has to deal with programs crashing, but I've
heard rumors that some don't.)
This is the one least under your control. OTOH, these modules are
already getting shafted. If something leaks an NSS handle, it's already
toast.
Most of the reason FF did shutdowns in the old days was to allow profile
shifts. I don't think on the fly profile shifts are supported anymore.
bob
I presume you mean for Firefox, not for NSS tests, which have to make
sure shutdown continues to work because other apps depend on it working.
bob
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