Glibc Now Enables Tuning Framework By Default

[phoronix]

Phoronix: Glibc Now Enables Tuning Framework By Default

Since the end of last year Glibc has offered a tunables framework that could be exposed via the --enable-tunables switch at compile-time while now it's being enabled by default...

http://www.phoronix.com/scan.php?page=news_item&px=glibc-enable-tunables

[bug77]

I don't get the "framework" aspect of all this. I mean, every run time has it's switches and parameters, what's so special about this one?

[discordian]

I don't get the "framework" aspect of all this. I mean, every run time has it's switches and parameters, what's so special about this one?

Not much, its just a hassle to have variables from different modules accessible from one place. if you dont want to maintain such an addtional global table by hand you need some buildtime and/or runtime helpers to collect them.

[RushPL]

As far as I understand it this feature can be useful in running broken programs with bad memory allocation.

https://www.gnu.org/software/libc/manual/html_node/Memory-Allocation-Tunables.html

For example glibc.malloc.check can be set to:

• 0 Ignore all errors. The default allocator continues to be in use, but all errors are silently ignored

Some very old games released over 10 years ago in binary only format will never be fixed so having a workaround in glibc sounds useful.

[jabl]

I don't get the "framework" aspect of all this. I mean, every run time has it's switches and parameters, what's so special about this one?

https://siddhesh.in/posts/the-story-of-tunables.html explains what glibc tunables are.

[bug77]

https://siddhesh.in/posts/the-story-of-tunables.html explains what glibc tunables are.

So basically it's taking all handling of environment variables and putting it in one place. A config. A cleanup task.

[unixguru]

I am shocked--shocked, I say!--to learn that this new misfeature somehow ended up being at the core of a major privilege escalation vulnerability in glibc. See the recent "Looney Tunables" exploit, mitigation of which requires major patching of glibc. Who could have possibly seen that coming? Fuck the GNU project, fuck glibc, and double fuck Ulrich Drepper and his butt buddy Linux Puttering.