1 /* drivers/misc/uid_stat.c
3 * Copyright (C) 2008 - 2009 Google, Inc.
5 * This software is licensed under the terms of the GNU General Public
6 * License version 2, as published by the Free Software Foundation, and
7 * may be copied, distributed, and modified under those terms.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
16 #include <asm/atomic.h>
18 #include <linux/err.h>
19 #include <linux/init.h>
20 #include <linux/kernel.h>
21 #include <linux/list.h>
22 #include <linux/proc_fs.h>
23 #include <linux/slab.h>
24 #include <linux/spinlock.h>
25 #include <linux/stat.h>
26 #include <linux/uid_stat.h>
28 static DEFINE_SPINLOCK(uid_lock);
29 static LIST_HEAD(uid_list);
30 static struct proc_dir_entry *parent;
33 struct list_head link;
39 static struct uid_stat *find_uid_stat(uid_t uid) {
41 struct uid_stat *entry;
43 spin_lock_irqsave(&uid_lock, flags);
44 list_for_each_entry(entry, &uid_list, link) {
45 if (entry->uid == uid) {
46 spin_unlock_irqrestore(&uid_lock, flags);
50 spin_unlock_irqrestore(&uid_lock, flags);
54 static int tcp_snd_read_proc(char *page, char **start, off_t off,
55 int count, int *eof, void *data)
60 struct uid_stat *uid_entry = (struct uid_stat *) data;
64 bytes = (unsigned int) (atomic_read(&uid_entry->tcp_snd) + INT_MIN);
65 p += sprintf(p, "%u\n", bytes);
66 len = (p - page) - off;
67 *eof = (len <= count) ? 1 : 0;
72 static int tcp_rcv_read_proc(char *page, char **start, off_t off,
73 int count, int *eof, void *data)
78 struct uid_stat *uid_entry = (struct uid_stat *) data;
82 bytes = (unsigned int) (atomic_read(&uid_entry->tcp_rcv) + INT_MIN);
83 p += sprintf(p, "%u\n", bytes);
84 len = (p - page) - off;
85 *eof = (len <= count) ? 1 : 0;
90 /* Create a new entry for tracking the specified uid. */
91 static struct uid_stat *create_stat(uid_t uid) {
94 struct uid_stat *new_uid;
95 struct proc_dir_entry *entry;
97 /* Create the uid stat struct and append it to the list. */
98 if ((new_uid = kmalloc(sizeof(struct uid_stat), GFP_KERNEL)) == NULL)
102 /* Counters start at INT_MIN, so we can track 4GB of network traffic. */
103 atomic_set(&new_uid->tcp_rcv, INT_MIN);
104 atomic_set(&new_uid->tcp_snd, INT_MIN);
106 spin_lock_irqsave(&uid_lock, flags);
107 list_add_tail(&new_uid->link, &uid_list);
108 spin_unlock_irqrestore(&uid_lock, flags);
110 sprintf(uid_s, "%d", uid);
111 entry = proc_mkdir(uid_s, parent);
113 /* Keep reference to uid_stat so we know what uid to read stats from. */
114 create_proc_read_entry("tcp_snd", S_IRUGO, entry , tcp_snd_read_proc,
117 create_proc_read_entry("tcp_rcv", S_IRUGO, entry, tcp_rcv_read_proc,
123 int uid_stat_tcp_snd(uid_t uid, int size) {
124 struct uid_stat *entry;
125 if ((entry = find_uid_stat(uid)) == NULL &&
126 ((entry = create_stat(uid)) == NULL)) {
129 atomic_add(size, &entry->tcp_snd);
133 int uid_stat_tcp_rcv(uid_t uid, int size) {
134 struct uid_stat *entry;
135 if ((entry = find_uid_stat(uid)) == NULL &&
136 ((entry = create_stat(uid)) == NULL)) {
139 atomic_add(size, &entry->tcp_rcv);
143 static int __init uid_stat_init(void)
145 parent = proc_mkdir("uid_stat", NULL);
147 pr_err("uid_stat: failed to create proc entry\n");
153 __initcall(uid_stat_init);