Re: [RFC][PATCH 4/5] utsname namespaces: sysctl hack

[Kirill Korotaev]

Serge,

> Please look closer at the patch.
> I *am* doing nothing with sysctls.
>
> system_utsname no longer exists, and the way to get to that is by using
> init_uts_ns.name.  That's all this does.
Sorry for being not concrete enough.
I mean switch () in the code. Until we decided how to virtualize 
sysctls/proc, I believe no dead code/hacks should be commited. IMHO.

FYI, I strongly object against virtualizing sysctls this way as it is 
not flexible and is a real hack from my POV.

Sure, change of system_utsname.sysname -> init_uts_ns.name.sysname is Ok.

Thanks,
Kirill

> > > Sysctl uts patch.  This clearly will need to be done another way, but
> > > since sysctl itself needs to be container aware, 'the right thing' is
> > > a separate patchset.
> > >
> > > Signed-off-by: Serge E. Hallyn <serue@xxxxxxxxxx>
> > > ---
> > > kernel/sysctl.c |   38 ++++++++++++++++++++++++++++----------
> > > 1 files changed, 28 insertions(+), 10 deletions(-)
> > >
> > > 40f7e1320c82efb6e875fc3bf44408cdfd093f21
> > > diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> > > index e82726f..c2b18ef 100644
> > > --- a/kernel/sysctl.c
> > > +++ b/kernel/sysctl.c
> > > @@ -233,8 +233,8 @@ static ctl_table kern_table[] = {
> > > 	{
> > > 		.ctl_name	= KERN_OSTYPE,
> > > 		.procname	= "ostype",
> > > -		.data		= system_utsname.sysname,
> > > -		.maxlen		= sizeof(system_utsname.sysname),
> > > +		.data		= init_uts_ns.name.sysname,
> > > +		.maxlen		= sizeof(init_uts_ns.name.sysname),
> > > 		.mode		= 0444,
> > > 		.proc_handler	= &proc_doutsstring,
> > > 		.strategy	= &sysctl_string,
> > > @@ -242,8 +242,8 @@ static ctl_table kern_table[] = {
> > > 	{
> > > 		.ctl_name	= KERN_OSRELEASE,
> > > 		.procname	= "osrelease",
> > > -		.data		= system_utsname.release,
> > > -		.maxlen		= sizeof(system_utsname.release),
> > > +		.data		= init_uts_ns.name.release,
> > > +		.maxlen		= sizeof(init_uts_ns.name.release),
> > > 		.mode		= 0444,
> > > 		.proc_handler	= &proc_doutsstring,
> > > 		.strategy	= &sysctl_string,
> > > @@ -251,8 +251,8 @@ static ctl_table kern_table[] = {
> > > 	{
> > > 		.ctl_name	= KERN_VERSION,
> > > 		.procname	= "version",
> > > -		.data		= system_utsname.version,
> > > -		.maxlen		= sizeof(system_utsname.version),
> > > +		.data		= init_uts_ns.name.version,
> > > +		.maxlen		= sizeof(init_uts_ns.name.version),
> > > 		.mode		= 0444,
> > > 		.proc_handler	= &proc_doutsstring,
> > > 		.strategy	= &sysctl_string,
> > > @@ -260,8 +260,8 @@ static ctl_table kern_table[] = {
> > > 	{
> > > 		.ctl_name	= KERN_NODENAME,
> > > 		.procname	= "hostname",
> > > -		.data		= system_utsname.nodename,
> > > -		.maxlen		= sizeof(system_utsname.nodename),
> > > +		.data		= init_uts_ns.name.nodename,
> > > +		.maxlen		= sizeof(init_uts_ns.name.nodename),
> > > 		.mode		= 0644,
> > > 		.proc_handler	= &proc_doutsstring,
> > > 		.strategy	= &sysctl_string,
> > > @@ -269,8 +269,8 @@ static ctl_table kern_table[] = {
> > > 	{
> > > 		.ctl_name	= KERN_DOMAINNAME,
> > > 		.procname	= "domainname",
> > > -		.data		= system_utsname.domainname,
> > > -		.maxlen		= sizeof(system_utsname.domainname),
> > > +		.data		= init_uts_ns.name.domainname,
> > > +		.maxlen		= sizeof(init_uts_ns.name.domainname),
> > > 		.mode		= 0644,
> > > 		.proc_handler	= &proc_doutsstring,
> > > 		.strategy	= &sysctl_string,
> > > @@ -1619,6 +1619,24 @@ static int proc_doutsstring(ctl_table *t
> > > {
> > > 	int r;
> > >
> > > +	switch (table->ctl_name) {
> > > +		case KERN_OSTYPE:
> > > +			table->data = utsname()->sysname;
> > > +			break;
> > > +		case KERN_OSRELEASE:
> > > +			table->data = utsname()->release;
> > > +			break;
> > > +		case KERN_VERSION:
> > > +			table->data = utsname()->version;
> > > +			break;
> > > +		case KERN_NODENAME:
> > > +			table->data = utsname()->nodename;
> > > +			break;
> > > +		case KERN_DOMAINNAME:
> > > +			table->data = utsname()->domainname;
> > > +			break;
> > > +	}
> > > +
> > > 	if (!write) {
> > > 		down_read(&uts_sem);
> > > 		r=proc_dostring(table,0,filp,buffer,lenp, ppos);


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