110 lines
3.0 KiB
C
110 lines
3.0 KiB
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>
|
|
|
|
static const struct genl_multicast_group quota_mcgrps[] = {
|
|
{ .name = "events", },
|
|
};
|
|
|
|
/* 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,
|
|
.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(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),
|
|
"a_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("a_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("a_genl_family) != 0)
|
|
printk(KERN_ERR
|
|
"VFS: Failed to create quota netlink interface.\n");
|
|
return 0;
|
|
};
|
|
|
|
module_init(quota_init);
|