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

["Serge E. Hallyn" <serue@us.ibm.com>]

Quoting Kirill Korotaev (dev@sw.ru):
> Serge,
> 
> can we do nothing with sysctls at this moment, instead of commiting hacks?

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.

-serge

> 
> 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@us.ibm.com>
> >---
> > 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);
>