[Devel] Re: [PATCH 4/9] namespaces: utsname: switch to using uts namespaces

[Randy.Dunlap]

On Fri, 19 May 2006 03:05:23 -0600 Eric W. Biederman wrote:

> "Randy.Dunlap" <rdunlap at xenotime.net> writes:
> 
> > On Thu, 18 May 2006 10:49:36 -0500 Serge E. Hallyn wrote:
> >
> >> Replace references to system_utsname to the per-process uts namespace
> >> where appropriate.  This includes things like uname.
> >> 
> >> Changes: Per Eric Biederman's comments, use the per-process uts namespace
> >> 	for ELF_PLATFORM, sunrpc, and parts of net/ipv4/ipconfig.c
> >> 
> >> Signed-off-by: Serge E. Hallyn <serue at us.ibm.com>
> 
> >
> > OK, here's my big comment/question.  I want to see <nodename> increased to
> > 256 bytes (per current POSIX), so each field of struct <variant>_utsname
> > needs be copied individually (I think) instead of doing a single
> > struct copy.
> 
> Where is it specified?  Looking at the spec as SUSV3 I don't see a size
> specified for nodename.

It's actually for hostname.  It looks to me like they are used
interchangeably.  yes/no?

gethostname:
http://www.opengroup.org/onlinepubs/009695399/functions/gethostname.html
sysconf:
http://www.opengroup.org/onlinepubs/009695399/functions/sysconf.html
unistd.h:
http://www.opengroup.org/onlinepubs/009695399/basedefs/unistd.h.html
limits.h:
http://www.opengroup.org/onlinepubs/009695399/basedefs/limits.h.html

>From the latter:
{HOST_NAME_MAX}
    Maximum length of a host name (not including the terminating null) as returned from the gethostname() function.
    Minimum Acceptable Value: {_POSIX_HOST_NAME_MAX}
(and)
{_POSIX_HOST_NAME_MAX}
    Maximum length of a host name (not including the terminating null) as returned from the gethostname() function.
    Value: 255



> > I've been working on this for the past few weeks (among other
> > things).  Sorry about the timing.
> > I could send patches for this against mainline in a few days,
> > but I'll be glad to listen to how it would be easiest for all of us
> > to handle.
> >
> > I'm probably a little over half done with my patches.
> > They will end up adding a lib/utsname.c that has functions for:
> >   put_oldold_uname()	// to user
> >   put_old_uname()	// to user
> >   put_new_uname()	// to user
> >   put_posix_uname()	// to user
> 
> Sounds reasonable, if we really need a 256 byte nodename.
> 
> As long as they take a pointer to the appropriate utsname
> structure these patches should not fundamentally conflict.


---
~Randy