[Devel] [PATCH rh7] venetstat: Add ioctl interface via VE cgroup

[Cyrill Gorcunov]

Here we add a special file into ve cgroup named
"venet_acct_ioctl" which would emulate old ioctls.

The write action into this file should pass
struct vz_tc_cg_req as an argument so that
it get unpacked into argument and command
for ioctl call and execute it.

https://jira.sw.ru/browse/PSBM-32277

Signed-off-by: Cyrill Gorcunov <gorcunov at virtuozzo.com>
CC: Andrey Vagin <avagin at virtuozzo.com>
CC: Vladimir Davydov <vdavydov at virtuozzo.com>
CC: Konstantin Khorenko <khorenko at virtuozzo.com>
CC: Pavel Emelyanov <xemul at virtuozzo.com>
---

Guys, take a look please, would such ioctl wrap do a trick
and be suitable for userspace?

 include/uapi/linux/vzctl_netstat.h |    5 +++++
 kernel/ve/vznetstat/vznetstat.c    |   30 ++++++++++++++++++++++++++++++
 2 files changed, 35 insertions(+)

Index: linux-pcs7.git/include/uapi/linux/vzctl_netstat.h
===================================================================
--- linux-pcs7.git.orig/include/uapi/linux/vzctl_netstat.h
+++ linux-pcs7.git/include/uapi/linux/vzctl_netstat.h
@@ -16,6 +16,11 @@
 typedef unsigned int envid_t;
 #endif
 
+struct vz_tc_cg_req {
+	__u32				cmd;
+	__u64				arg;
+};
+
 /*
  * Traffic accouting management ioctl
  */
Index: linux-pcs7.git/kernel/ve/vznetstat/vznetstat.c
===================================================================
--- linux-pcs7.git.orig/kernel/ve/vznetstat/vznetstat.c
+++ linux-pcs7.git/kernel/ve/vznetstat/vznetstat.c
@@ -21,6 +21,7 @@
 #include <net/ip.h>
 #include <linux/in6.h>
 #include <linux/module.h>
+#include <linux/cgroup.h>
 
 #include <linux/ve.h>
 #include <linux/venet.h>
@@ -974,6 +975,33 @@ static struct file_operations proc_venet
         .release	= seq_release,
 };
 
+static ssize_t cg_acct_write(struct cgroup *cgrp, struct cftype *cft,
+			     struct file *file,
+			     const char __user *buf,
+			     size_t nbytes, loff_t *ppos)
+{
+	struct vz_tc_cg_req req;
+	int ret;
+
+	if (nbytes != sizeof(req))
+		return -EINVAL;
+
+	if (copy_from_user(&req, buf, sizeof(req)))
+	    return -EFAULT;
+
+	ret = venet_acct_ioctl(NULL, req.cmd, req.arg);
+
+	return ret ?: sizeof(req);
+}
+
+static struct cftype ve_cft_stat[] = {
+	{
+		.name	= "venet_acct_ioctl",
+		.flags	= CFTYPE_NOT_ON_ROOT,
+		.write	= cg_acct_write,
+	},
+};
+
 /*
  * ---------------------------------------------------------------------------
  * Initialization
@@ -1002,12 +1030,14 @@ int __init venetstat_init(void)
 		printk(KERN_WARNING "VENET: can't make venetstat_v6 proc entry\n");
 
 #endif
+	WARN_ON(cgroup_add_cftypes(&ve_subsys, ve_cft_stat));
 	vzioctl_register(&tc_ioctl_info);
 	return 0;
 }
 
 void __exit venetstat_exit(void)
 {
+	WARN_ON(cgroup_rm_cftypes(&ve_subsys, ve_cft_stat));
 	vzioctl_unregister(&tc_ioctl_info);
 	venet_acct_destroy_all_stat();