[PATCH] Use statfs64() in shm_open() and posix_getpt().

[Joseph S. Myers]

On Sat, 2 Aug 2014, Mike Frysinger wrote:

> right, posix_openpt is part of libc, but shm_open is part of librt.  so the 
> former should use __statfs64 to avoid the PLT while the latter should use 
> statfs64.

No, both should use __statfs64 as statfs64 is not part of the POSIX 
namespace but shm_open is.  As previously discussed, PLT avoidance and 
being namespace-clean are separate issues.

That does of course mean __statfs64 needs to be exported from libc.so.  
Although you could use a GLIBC_PRIVATE export (and that's the conservative 
approach at this development stage), eventually we'll want such exports at 
public symbol versions as part of a fix for bug 14106.  (statfs isn't part 
of a standard, so the need for such a public export is a bit less clear, 
but it still seems appropriate given that you can use <sys/statfs.h> 
without _LARGEFILE64_SOURCE being defined, and in that case it seems 
reasonable to consider statfs64 part of the user's namespace.)

-- 
Joseph S. Myers
joseph@codesourcery.com