[thirdparty/kernel/linux.git] / fs / quota / netlink.c

// SPDX-License-Identifier: GPL-2.0
#include <linux/cred.h>
#include <linux/init.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>

static const struct genl_multicast_group quota_mcgrps[] = {
	{ .name = "events", },
};

/* Netlink family structure for quota */
static struct genl_family quota_genl_family __ro_after_init = {
	.module = THIS_MODULE,
	.hdrsize = 0,
	.name = "VFS_DQUOT",
	.version = 1,
	.maxattr = QUOTA_NL_A_MAX,
	.mcgrps = quota_mcgrps,
	.n_mcgrps = ARRAY_SIZE(quota_mcgrps),
};

/**
 * quota_send_warning - Send warning to userspace about exceeded quota
 * @qid: The kernel internal quota identifier.
 * @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_64bit(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_64bit(skb, QUOTA_NL_A_EXCESS_ID,
				from_kqid_munged(&init_user_ns, qid),
				QUOTA_NL_A_PAD);
	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_64bit(skb, QUOTA_NL_A_CAUSED_ID,
				from_kuid_munged(&init_user_ns, current_uid()),
				QUOTA_NL_A_PAD);
	if (ret)
		goto attr_err_out;
	genlmsg_end(skb, msg_head);

	genlmsg_multicast(&quota_genl_family, skb, 0, 0, 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");
	return 0;
};
fs_initcall(quota_init);
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
799a9d44 CH	2	#include <linux/cred.h>
799a9d44 CH	3	#include <linux/init.h>
799a9d44 CH	4	#include <linux/kernel.h>
	5	#include <linux/quotaops.h>
	6	#include <linux/sched.h>
5a0e3ad6	7	#include <linux/slab.h>
799a9d44 CH	8	#include <net/netlink.h>
	9	#include <net/genetlink.h>
	10
2a94fe48 JB	11	static const struct genl_multicast_group quota_mcgrps[] = {
	12	{ .name = "events", },
	13	};
	14
799a9d44	15	/* Netlink family structure for quota */
56989f6d	16	static struct genl_family quota_genl_family __ro_after_init = {
489111e5	17	.module = THIS_MODULE,
799a9d44 CH	18	.hdrsize = 0,
	19	.name = "VFS_DQUOT",
	20	.version = 1,
	21	.maxattr = QUOTA_NL_A_MAX,
2a94fe48 JB	22	.mcgrps = quota_mcgrps,
2a94fe48 JB	23	.n_mcgrps = ARRAY_SIZE(quota_mcgrps),
2ecf7536 JB	24	};
2ecf7536 JB	25
799a9d44 CH	26	/**
799a9d44 CH	27	* quota_send_warning - Send warning to userspace about exceeded quota
2c15ac5b	28	* @qid: The kernel internal quota identifier.
799a9d44 CH	29	* @dev: The device on which the fs is mounted (sb->s_dev)
	30	* @warntype: The type of the warning: QUOTA_NL_...
	31	*
	32	* This can be used by filesystems (including those which don't use
	33	* dquot) to send a message to userspace relating to quota limits.
	34	*
	35	*/
	36
431f1974	37	void quota_send_warning(struct kqid qid, dev_t dev,
799a9d44 CH	38	const char warntype)
	39	{
	40	static atomic_t seq;
	41	struct sk_buff *skb;
	42	void *msg_head;
	43	int ret;
	44	int msg_size = 4 * nla_total_size(sizeof(u32)) +
3c6f3714	45	2 * nla_total_size_64bit(sizeof(u64));
799a9d44 CH	46
	47	/* We have to allocate using GFP_NOFS as we are called from a
	48	* filesystem performing write and thus further recursion into
	49	* the fs to free some data could cause deadlocks. */
	50	skb = genlmsg_new(msg_size, GFP_NOFS);
	51	if (!skb) {
	52	printk(KERN_ERR
	53	"VFS: Not enough memory to send quota warning.\n");
	54	return;
	55	}
	56	msg_head = genlmsg_put(skb, 0, atomic_add_return(1, &seq),
	57	&quota_genl_family, 0, QUOTA_NL_C_WARNING);
	58	if (!msg_head) {
	59	printk(KERN_ERR
	60	"VFS: Cannot store netlink header in quota warning.\n");
	61	goto err_out;
	62	}
431f1974	63	ret = nla_put_u32(skb, QUOTA_NL_A_QTYPE, qid.type);
799a9d44 CH	64	if (ret)
799a9d44 CH	65	goto attr_err_out;
3c6f3714 ND	66	ret = nla_put_u64_64bit(skb, QUOTA_NL_A_EXCESS_ID,
	67	from_kqid_munged(&init_user_ns, qid),
	68	QUOTA_NL_A_PAD);
799a9d44 CH	69	if (ret)
	70	goto attr_err_out;
	71	ret = nla_put_u32(skb, QUOTA_NL_A_WARNING, warntype);
	72	if (ret)
	73	goto attr_err_out;
	74	ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MAJOR, MAJOR(dev));
	75	if (ret)
	76	goto attr_err_out;
	77	ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MINOR, MINOR(dev));
	78	if (ret)
	79	goto attr_err_out;
3c6f3714 ND	80	ret = nla_put_u64_64bit(skb, QUOTA_NL_A_CAUSED_ID,
	81	from_kuid_munged(&init_user_ns, current_uid()),
	82	QUOTA_NL_A_PAD);
799a9d44 CH	83	if (ret)
	84	goto attr_err_out;
	85	genlmsg_end(skb, msg_head);
	86
2a94fe48	87	genlmsg_multicast(&quota_genl_family, skb, 0, 0, GFP_NOFS);
799a9d44 CH	88	return;
	89	attr_err_out:
	90	printk(KERN_ERR "VFS: Not enough space to compose quota message!\n");
	91	err_out:
	92	kfree_skb(skb);
	93	}
	94	EXPORT_SYMBOL(quota_send_warning);
	95
	96	static int __init quota_init(void)
	97	{
	98	if (genl_register_family(&quota_genl_family) != 0)
	99	printk(KERN_ERR
	100	"VFS: Failed to create quota netlink interface.\n");
	101	return 0;
	102	};
7da54463	103	fs_initcall(quota_init);