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

[ebiederm@xmission.com (Eric W. Biederman)]

"Randy.Dunlap" <rdunlap@xenotime.net> writes:

> 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.
>
> 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_unmame()	// to user
>   put_old_uname()	// to user
>   put_new_uname()	// to user
>   put_posix_uname()	// to user

Looking 256 at least makes sense to hold a dns fully qualified domain
name.  So even if it isn't specified by posix is make sense.

Can we please make the structure we return to user space look something
like:

struct long_utsname {
	char *sysname;
	char *nodename;
	char *release;
	char *version;
	char *machine;
        char *domainname;
        char buf[0];
}

int sys_long_uname(char *buf, size_t bufsz);

So we don't hard code the maximum length of these strings into the user
interface, and can just return more by increasing our buffer size.

Eric