[Devel] 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 at 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);
>>
>