Avoiding sysctl at program startup using ELF aux vector (was: concurrent sysctl implementation)

Marius Strobl marius at alchemy.franken.de
Tue Jun 29 08:46:13 UTC 2010


On Mon, Jun 28, 2010 at 05:48:59PM +0300, Kostik Belousov wrote:
> On Wed, Jun 23, 2010 at 11:09:59PM +0200, Jeremie Le Hen wrote:
> > Hi Kostik,
> > 
> > This patch seems to have faded out from memory.  Is it possible to go
> > forward and commit it?
> I refreshed the patch. Hopefully, nobody will object, and I commit it
> shortly.
> 
> > 
> > Thanks,
> > Regards.
> > 
> > On Sat, Jul 25, 2009 at 12:29:16AM +0300, Kostik Belousov wrote:
> > > Below is the prototype that seems to work for me both with patched and
> > > old rtld on i386. Patch also contains bits for amd64 that I did not
> > > tested yet. All other arches are not buildable for now.
> > > 
> > > Patch completely eliminates sysctl syscalls from the rtld and libc
> > > startup. Without the patch, a single run of /bin/ls did 6 sysctls,
> > > with the patch, no sysctls is queried at all.
> > > 
> Comparing with the originally posted patch, I added support for all
> architectures, tested amd64 and ia32 on amd64, and converted getpagesizes(3)
> that added two more startup sysctls.
> 
> Would be nice to get a testing for at least some !x86 architectures
> before the commit, I added some people who helped me in past, to the Cc:.
> 

Doesn't look good on sparc64:
<...>
NFS ROOT: 192.168.1.40:/usr/data/nfsroot/sparc64
dc1: link state changed to UP
pid 24 (ifconfig), uid 0: exited on signal 11
Segmentation fault
Interface  IP-Address  Broadcast
pid 29 (rcorder), uid 0: exited on signal 11
Segmentation fault
pid 30 (grep), uid 0: exited on signal 11
Segmentation fault
pid 31 (rcorder), uid 0: exited on signal 11
Segmentation fault
 
pid 32 (date), uid 0: exited on signal 11
Segmentation fault
Jun 29 12:20:50 getty[36]: open /dev/ttyv3: No such file or directory
<...>

Unfortunately, I currently lack the time to debug this.

Marius



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