[deliverable/linux.git] / fs / quota / netlink.c


#include <linux/cred.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/quotaops.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <net/netlink.h>
#include <net/genetlink.h>

/* Netlink family structure for quota */
static struct genl_family quota_genl_family = {
	/*
	 * Needed due to multicast group ID abuse - old code assumed
	 * the family ID was also a valid multicast group ID (which
	 * isn't true) and userspace might thus rely on it. Assign a
	 * static ID for this group to make dealing with that easier.
	 */
	.id = GENL_ID_VFS_DQUOT,
	.hdrsize = 0,
	.name = "VFS_DQUOT",
	.version = 1,
	.maxattr = QUOTA_NL_A_MAX,
};

static struct genl_multicast_group quota_mcgrp = {
	.name = "events",
};

/**
 * quota_send_warning - Send warning to userspace about exceeded quota
 * @type: The quota type: USRQQUOTA, GRPQUOTA,...
 * @id: The user or group id of the quota that was exceeded
 * @dev: The device on which the fs is mounted (sb->s_dev)
 * @warntype: The type of the warning: QUOTA_NL_...
 *
 * This can be used by filesystems (including those which don't use
 * dquot) to send a message to userspace relating to quota limits.
 *
 */

void quota_send_warning(struct kqid qid, dev_t dev,
			const char warntype)
{
	static atomic_t seq;
	struct sk_buff *skb;
	void *msg_head;
	int ret;
	int msg_size = 4 * nla_total_size(sizeof(u32)) +
		       2 * nla_total_size(sizeof(u64));

	/* We have to allocate using GFP_NOFS as we are called from a
	 * filesystem performing write and thus further recursion into
	 * the fs to free some data could cause deadlocks. */
	skb = genlmsg_new(msg_size, GFP_NOFS);
	if (!skb) {
		printk(KERN_ERR
		  "VFS: Not enough memory to send quota warning.\n");
		return;
	}
	msg_head = genlmsg_put(skb, 0, atomic_add_return(1, &seq),
			&quota_genl_family, 0, QUOTA_NL_C_WARNING);
	if (!msg_head) {
		printk(KERN_ERR
		  "VFS: Cannot store netlink header in quota warning.\n");
		goto err_out;
	}
	ret = nla_put_u32(skb, QUOTA_NL_A_QTYPE, qid.type);
	if (ret)
		goto attr_err_out;
	ret = nla_put_u64(skb, QUOTA_NL_A_EXCESS_ID,
			  from_kqid_munged(&init_user_ns, qid));
	if (ret)
		goto attr_err_out;
	ret = nla_put_u32(skb, QUOTA_NL_A_WARNING, warntype);
	if (ret)
		goto attr_err_out;
	ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MAJOR, MAJOR(dev));
	if (ret)
		goto attr_err_out;
	ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MINOR, MINOR(dev));
	if (ret)
		goto attr_err_out;
	ret = nla_put_u64(skb, QUOTA_NL_A_CAUSED_ID,
			  from_kuid_munged(&init_user_ns, current_uid()));
	if (ret)
		goto attr_err_out;
	genlmsg_end(skb, msg_head);

	genlmsg_multicast(skb, 0, quota_mcgrp.id, GFP_NOFS);
	return;
attr_err_out:
	printk(KERN_ERR "VFS: Not enough space to compose quota message!\n");
err_out:
	kfree_skb(skb);
}
EXPORT_SYMBOL(quota_send_warning);

static int __init quota_init(void)
{
	if (genl_register_family(&quota_genl_family) != 0)
		printk(KERN_ERR
		       "VFS: Failed to create quota netlink interface.\n");
	if (genl_register_mc_group(&quota_genl_family, &quota_mcgrp))
		printk(KERN_ERR
		       "VFS: Failed to register quota mcast group.\n");
	return 0;
};

module_init(quota_init);
Commit	Line	Data
799a9d44 CH	1
	2	#include <linux/cred.h>
	3	#include <linux/init.h>
	4	#include <linux/module.h>
	5	#include <linux/kernel.h>
	6	#include <linux/quotaops.h>
	7	#include <linux/sched.h>
5a0e3ad6	8	#include <linux/slab.h>
799a9d44 CH	9	#include <net/netlink.h>
	10	#include <net/genetlink.h>
	11
	12	/* Netlink family structure for quota */
	13	static struct genl_family quota_genl_family = {
2ecf7536 JB	14	/*
	15	* Needed due to multicast group ID abuse - old code assumed
	16	* the family ID was also a valid multicast group ID (which
	17	* isn't true) and userspace might thus rely on it. Assign a
	18	* static ID for this group to make dealing with that easier.
	19	*/
	20	.id = GENL_ID_VFS_DQUOT,
799a9d44 CH	21	.hdrsize = 0,
	22	.name = "VFS_DQUOT",
	23	.version = 1,
	24	.maxattr = QUOTA_NL_A_MAX,
	25	};
	26
2ecf7536 JB	27	static struct genl_multicast_group quota_mcgrp = {
	28	.name = "events",
	29	};
	30
799a9d44 CH	31	/**
	32	* quota_send_warning - Send warning to userspace about exceeded quota
	33	* @type: The quota type: USRQQUOTA, GRPQUOTA,...
	34	* @id: The user or group id of the quota that was exceeded
	35	* @dev: The device on which the fs is mounted (sb->s_dev)
	36	* @warntype: The type of the warning: QUOTA_NL_...
	37	*
	38	* This can be used by filesystems (including those which don't use
	39	* dquot) to send a message to userspace relating to quota limits.
	40	*
	41	*/
	42
431f1974	43	void quota_send_warning(struct kqid qid, dev_t dev,
799a9d44 CH	44	const char warntype)
	45	{
	46	static atomic_t seq;
	47	struct sk_buff *skb;
	48	void *msg_head;
	49	int ret;
	50	int msg_size = 4 * nla_total_size(sizeof(u32)) +
	51	2 * nla_total_size(sizeof(u64));
	52
	53	/* We have to allocate using GFP_NOFS as we are called from a
	54	* filesystem performing write and thus further recursion into
	55	* the fs to free some data could cause deadlocks. */
	56	skb = genlmsg_new(msg_size, GFP_NOFS);
	57	if (!skb) {
	58	printk(KERN_ERR
	59	"VFS: Not enough memory to send quota warning.\n");
	60	return;
	61	}
	62	msg_head = genlmsg_put(skb, 0, atomic_add_return(1, &seq),
	63	&quota_genl_family, 0, QUOTA_NL_C_WARNING);
	64	if (!msg_head) {
	65	printk(KERN_ERR
	66	"VFS: Cannot store netlink header in quota warning.\n");
	67	goto err_out;
	68	}
431f1974	69	ret = nla_put_u32(skb, QUOTA_NL_A_QTYPE, qid.type);
799a9d44 CH	70	if (ret)
799a9d44 CH	71	goto attr_err_out;
431f1974 EB	72	ret = nla_put_u64(skb, QUOTA_NL_A_EXCESS_ID,
431f1974 EB	73	from_kqid_munged(&init_user_ns, qid));
799a9d44 CH	74	if (ret)
	75	goto attr_err_out;
	76	ret = nla_put_u32(skb, QUOTA_NL_A_WARNING, warntype);
	77	if (ret)
	78	goto attr_err_out;
	79	ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MAJOR, MAJOR(dev));
	80	if (ret)
	81	goto attr_err_out;
	82	ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MINOR, MINOR(dev));
	83	if (ret)
	84	goto attr_err_out;
431f1974 EB	85	ret = nla_put_u64(skb, QUOTA_NL_A_CAUSED_ID,
431f1974 EB	86	from_kuid_munged(&init_user_ns, current_uid()));
799a9d44 CH	87	if (ret)
	88	goto attr_err_out;
	89	genlmsg_end(skb, msg_head);
	90
2ecf7536	91	genlmsg_multicast(skb, 0, quota_mcgrp.id, GFP_NOFS);
799a9d44 CH	92	return;
	93	attr_err_out:
	94	printk(KERN_ERR "VFS: Not enough space to compose quota message!\n");
	95	err_out:
	96	kfree_skb(skb);
	97	}
	98	EXPORT_SYMBOL(quota_send_warning);
	99
	100	static int __init quota_init(void)
	101	{
	102	if (genl_register_family(&quota_genl_family) != 0)
	103	printk(KERN_ERR
	104	"VFS: Failed to create quota netlink interface.\n");
2ecf7536 JB	105	if (genl_register_mc_group(&quota_genl_family, &quota_mcgrp))
	106	printk(KERN_ERR
	107	"VFS: Failed to register quota mcast group.\n");
799a9d44 CH	108	return 0;
	109	};
	110
	111	module_init(quota_init);