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/* drivers/misc/uid_stat.c
*
* Copyright (C) 2008 - 2009 Google, Inc.
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#include <asm/atomic.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/stat.h>
#include <linux/uid_stat.h>
#include <net/activity_stats.h>
static DEFINE_SPINLOCK(uid_lock);
static LIST_HEAD(uid_list);
static struct proc_dir_entry *parent;
struct uid_stat {
struct list_head link;
uid_t uid;
atomic_t tcp_rcv;
atomic_t tcp_snd;
};
static struct uid_stat *find_uid_stat(uid_t uid) {
struct uid_stat *entry;
list_for_each_entry(entry, &uid_list, link) {
if (entry->uid == uid) {
return entry;
}
}
return NULL;
}
static int uid_stat_atomic_int_show(struct seq_file *m, void *v)
{
unsigned int bytes;
atomic_t *counter = m->private;
bytes = (unsigned int) (atomic_read(counter) + INT_MIN);
return seq_printf(m, "%u\n", bytes);
}
static int uid_stat_read_atomic_int_open(struct inode *inode, struct file *file)
{
return single_open(file, uid_stat_atomic_int_show, PDE_DATA(inode));
}
static const struct file_operations uid_stat_read_atomic_int_fops = {
.open = uid_stat_read_atomic_int_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
/* Create a new entry for tracking the specified uid. */
static struct uid_stat *create_stat(uid_t uid) {
struct uid_stat *new_uid;
/* Create the uid stat struct and append it to the list. */
new_uid = kmalloc(sizeof(struct uid_stat), GFP_ATOMIC);
if (!new_uid)
return NULL;
new_uid->uid = uid;
/* Counters start at INT_MIN, so we can track 4GB of network traffic. */
atomic_set(&new_uid->tcp_rcv, INT_MIN);
atomic_set(&new_uid->tcp_snd, INT_MIN);
list_add_tail(&new_uid->link, &uid_list);
return new_uid;
}
static void create_stat_proc(struct uid_stat *new_uid)
{
char uid_s[32];
struct proc_dir_entry *entry;
sprintf(uid_s, "%d", new_uid->uid);
entry = proc_mkdir(uid_s, parent);
/* Keep reference to uid_stat so we know what uid to read stats from. */
proc_create_data("tcp_snd", S_IRUGO, entry,
&uid_stat_read_atomic_int_fops, &new_uid->tcp_snd);
proc_create_data("tcp_rcv", S_IRUGO, entry,
&uid_stat_read_atomic_int_fops, &new_uid->tcp_rcv);
}
static struct uid_stat *find_or_create_uid_stat(uid_t uid)
{
struct uid_stat *entry;
unsigned long flags;
spin_lock_irqsave(&uid_lock, flags);
entry = find_uid_stat(uid);
if (entry) {
spin_unlock_irqrestore(&uid_lock, flags);
return entry;
}
entry = create_stat(uid);
spin_unlock_irqrestore(&uid_lock, flags);
if (entry)
create_stat_proc(entry);
return entry;
}
int uid_stat_tcp_snd(uid_t uid, int size) {
struct uid_stat *entry;
activity_stats_update();
entry = find_or_create_uid_stat(uid);
if (!entry)
return -1;
atomic_add(size, &entry->tcp_snd);
return 0;
}
int uid_stat_tcp_rcv(uid_t uid, int size) {
struct uid_stat *entry;
activity_stats_update();
entry = find_or_create_uid_stat(uid);
if (!entry)
return -1;
atomic_add(size, &entry->tcp_rcv);
return 0;
}
static int __init uid_stat_init(void)
{
parent = proc_mkdir("uid_stat", NULL);
if (!parent) {
pr_err("uid_stat: failed to create proc entry\n");
return -1;
}
return 0;
}
__initcall(uid_stat_init);
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