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1#include <linux/cred.h>
2#include <linux/init.h>
3#include <linux/kernel.h>
4#include <linux/quotaops.h>
5#include <linux/sched.h>
6#include <linux/slab.h>
7#include <net/netlink.h>
8#include <net/genetlink.h>
9
10static const struct genl_multicast_group quota_mcgrps[] = {
11 { .name = "events", },
12};
13
14/* Netlink family structure for quota */
15static struct genl_family quota_genl_family __ro_after_init = {
16 .module = THIS_MODULE,
17 .hdrsize = 0,
18 .name = "VFS_DQUOT",
19 .version = 1,
20 .maxattr = QUOTA_NL_A_MAX,
21 .mcgrps = quota_mcgrps,
22 .n_mcgrps = ARRAY_SIZE(quota_mcgrps),
23};
24
25/**
26 * quota_send_warning - Send warning to userspace about exceeded quota
27 * @qid: The kernel internal quota identifier.
28 * @dev: The device on which the fs is mounted (sb->s_dev)
29 * @warntype: The type of the warning: QUOTA_NL_...
30 *
31 * This can be used by filesystems (including those which don't use
32 * dquot) to send a message to userspace relating to quota limits.
33 *
34 */
35
36void quota_send_warning(struct kqid qid, dev_t dev,
37 const char warntype)
38{
39 static atomic_t seq;
40 struct sk_buff *skb;
41 void *msg_head;
42 int ret;
43 int msg_size = 4 * nla_total_size(sizeof(u32)) +
44 2 * nla_total_size_64bit(sizeof(u64));
45
46 /* We have to allocate using GFP_NOFS as we are called from a
47 * filesystem performing write and thus further recursion into
48 * the fs to free some data could cause deadlocks. */
49 skb = genlmsg_new(msg_size, GFP_NOFS);
50 if (!skb) {
51 printk(KERN_ERR
52 "VFS: Not enough memory to send quota warning.\n");
53 return;
54 }
55 msg_head = genlmsg_put(skb, 0, atomic_add_return(1, &seq),
56 "a_genl_family, 0, QUOTA_NL_C_WARNING);
57 if (!msg_head) {
58 printk(KERN_ERR
59 "VFS: Cannot store netlink header in quota warning.\n");
60 goto err_out;
61 }
62 ret = nla_put_u32(skb, QUOTA_NL_A_QTYPE, qid.type);
63 if (ret)
64 goto attr_err_out;
65 ret = nla_put_u64_64bit(skb, QUOTA_NL_A_EXCESS_ID,
66 from_kqid_munged(&init_user_ns, qid),
67 QUOTA_NL_A_PAD);
68 if (ret)
69 goto attr_err_out;
70 ret = nla_put_u32(skb, QUOTA_NL_A_WARNING, warntype);
71 if (ret)
72 goto attr_err_out;
73 ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MAJOR, MAJOR(dev));
74 if (ret)
75 goto attr_err_out;
76 ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MINOR, MINOR(dev));
77 if (ret)
78 goto attr_err_out;
79 ret = nla_put_u64_64bit(skb, QUOTA_NL_A_CAUSED_ID,
80 from_kuid_munged(&init_user_ns, current_uid()),
81 QUOTA_NL_A_PAD);
82 if (ret)
83 goto attr_err_out;
84 genlmsg_end(skb, msg_head);
85
86 genlmsg_multicast("a_genl_family, skb, 0, 0, GFP_NOFS);
87 return;
88attr_err_out:
89 printk(KERN_ERR "VFS: Not enough space to compose quota message!\n");
90err_out:
91 kfree_skb(skb);
92}
93EXPORT_SYMBOL(quota_send_warning);
94
95static int __init quota_init(void)
96{
97 if (genl_register_family("a_genl_family) != 0)
98 printk(KERN_ERR
99 "VFS: Failed to create quota netlink interface.\n");
100 return 0;
101};
102fs_initcall(quota_init);
1#include <linux/cred.h>
2#include <linux/init.h>
3#include <linux/kernel.h>
4#include <linux/quotaops.h>
5#include <linux/sched.h>
6#include <linux/slab.h>
7#include <net/netlink.h>
8#include <net/genetlink.h>
9
10static const struct genl_multicast_group quota_mcgrps[] = {
11 { .name = "events", },
12};
13
14/* Netlink family structure for quota */
15static struct genl_family quota_genl_family = {
16 /*
17 * Needed due to multicast group ID abuse - old code assumed
18 * the family ID was also a valid multicast group ID (which
19 * isn't true) and userspace might thus rely on it. Assign a
20 * static ID for this group to make dealing with that easier.
21 */
22 .id = GENL_ID_VFS_DQUOT,
23 .hdrsize = 0,
24 .name = "VFS_DQUOT",
25 .version = 1,
26 .maxattr = QUOTA_NL_A_MAX,
27 .mcgrps = quota_mcgrps,
28 .n_mcgrps = ARRAY_SIZE(quota_mcgrps),
29};
30
31/**
32 * quota_send_warning - Send warning to userspace about exceeded quota
33 * @qid: The kernel internal quota identifier.
34 * @dev: The device on which the fs is mounted (sb->s_dev)
35 * @warntype: The type of the warning: QUOTA_NL_...
36 *
37 * This can be used by filesystems (including those which don't use
38 * dquot) to send a message to userspace relating to quota limits.
39 *
40 */
41
42void quota_send_warning(struct kqid qid, dev_t dev,
43 const char warntype)
44{
45 static atomic_t seq;
46 struct sk_buff *skb;
47 void *msg_head;
48 int ret;
49 int msg_size = 4 * nla_total_size(sizeof(u32)) +
50 2 * nla_total_size(sizeof(u64));
51
52 /* We have to allocate using GFP_NOFS as we are called from a
53 * filesystem performing write and thus further recursion into
54 * the fs to free some data could cause deadlocks. */
55 skb = genlmsg_new(msg_size, GFP_NOFS);
56 if (!skb) {
57 printk(KERN_ERR
58 "VFS: Not enough memory to send quota warning.\n");
59 return;
60 }
61 msg_head = genlmsg_put(skb, 0, atomic_add_return(1, &seq),
62 "a_genl_family, 0, QUOTA_NL_C_WARNING);
63 if (!msg_head) {
64 printk(KERN_ERR
65 "VFS: Cannot store netlink header in quota warning.\n");
66 goto err_out;
67 }
68 ret = nla_put_u32(skb, QUOTA_NL_A_QTYPE, qid.type);
69 if (ret)
70 goto attr_err_out;
71 ret = nla_put_u64(skb, QUOTA_NL_A_EXCESS_ID,
72 from_kqid_munged(&init_user_ns, qid));
73 if (ret)
74 goto attr_err_out;
75 ret = nla_put_u32(skb, QUOTA_NL_A_WARNING, warntype);
76 if (ret)
77 goto attr_err_out;
78 ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MAJOR, MAJOR(dev));
79 if (ret)
80 goto attr_err_out;
81 ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MINOR, MINOR(dev));
82 if (ret)
83 goto attr_err_out;
84 ret = nla_put_u64(skb, QUOTA_NL_A_CAUSED_ID,
85 from_kuid_munged(&init_user_ns, current_uid()));
86 if (ret)
87 goto attr_err_out;
88 genlmsg_end(skb, msg_head);
89
90 genlmsg_multicast("a_genl_family, skb, 0, 0, GFP_NOFS);
91 return;
92attr_err_out:
93 printk(KERN_ERR "VFS: Not enough space to compose quota message!\n");
94err_out:
95 kfree_skb(skb);
96}
97EXPORT_SYMBOL(quota_send_warning);
98
99static int __init quota_init(void)
100{
101 if (genl_register_family("a_genl_family) != 0)
102 printk(KERN_ERR
103 "VFS: Failed to create quota netlink interface.\n");
104 return 0;
105};
106fs_initcall(quota_init);