1 /* drivers/misc/uid_stat.c
2 *
3 * Copyright (C) 2008 - 2009 Google, Inc.
4 *
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.
8 *
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.
13 *
14 */
15
16 #include <asm/atomic.h>
17
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/seq_file.h>
24 #include <linux/slab.h>
25 #include <linux/spinlock.h>
26 #include <linux/stat.h>
27 #include <linux/uid_stat.h>
28 #include <net/activity_stats.h>
29
30 static DEFINE_SPINLOCK(uid_lock);
31 static LIST_HEAD(uid_list);
32 static struct proc_dir_entry *parent;
33
34 struct uid_stat {
35 struct list_head link;
36 uid_t uid;
37 atomic_t tcp_rcv;
38 atomic_t tcp_snd;
39 };
40
find_uid_stat(uid_t uid)41 static struct uid_stat *find_uid_stat(uid_t uid) {
42 struct uid_stat *entry;
43
44 list_for_each_entry(entry, &uid_list, link) {
45 if (entry->uid == uid) {
46 return entry;
47 }
48 }
49 return NULL;
50 }
51
uid_stat_atomic_int_show(struct seq_file * m,void * v)52 static int uid_stat_atomic_int_show(struct seq_file *m, void *v)
53 {
54 unsigned int bytes;
55 atomic_t *counter = m->private;
56
57 bytes = (unsigned int) (atomic_read(counter) + INT_MIN);
58 return seq_printf(m, "%u\n", bytes);
59 }
60
uid_stat_read_atomic_int_open(struct inode * inode,struct file * file)61 static int uid_stat_read_atomic_int_open(struct inode *inode, struct file *file)
62 {
63 return single_open(file, uid_stat_atomic_int_show, PDE_DATA(inode));
64 }
65
66 static const struct file_operations uid_stat_read_atomic_int_fops = {
67 .open = uid_stat_read_atomic_int_open,
68 .read = seq_read,
69 .llseek = seq_lseek,
70 .release = single_release,
71 };
72
73 /* Create a new entry for tracking the specified uid. */
create_stat(uid_t uid)74 static struct uid_stat *create_stat(uid_t uid) {
75 struct uid_stat *new_uid;
76 /* Create the uid stat struct and append it to the list. */
77 new_uid = kmalloc(sizeof(struct uid_stat), GFP_ATOMIC);
78 if (!new_uid)
79 return NULL;
80
81 new_uid->uid = uid;
82 /* Counters start at INT_MIN, so we can track 4GB of network traffic. */
83 atomic_set(&new_uid->tcp_rcv, INT_MIN);
84 atomic_set(&new_uid->tcp_snd, INT_MIN);
85
86 list_add_tail(&new_uid->link, &uid_list);
87 return new_uid;
88 }
89
create_stat_proc(struct uid_stat * new_uid)90 static void create_stat_proc(struct uid_stat *new_uid)
91 {
92 char uid_s[32];
93 struct proc_dir_entry *entry;
94 sprintf(uid_s, "%d", new_uid->uid);
95 entry = proc_mkdir(uid_s, parent);
96
97 /* Keep reference to uid_stat so we know what uid to read stats from. */
98 proc_create_data("tcp_snd", S_IRUGO, entry,
99 &uid_stat_read_atomic_int_fops, &new_uid->tcp_snd);
100
101 proc_create_data("tcp_rcv", S_IRUGO, entry,
102 &uid_stat_read_atomic_int_fops, &new_uid->tcp_rcv);
103 }
104
find_or_create_uid_stat(uid_t uid)105 static struct uid_stat *find_or_create_uid_stat(uid_t uid)
106 {
107 struct uid_stat *entry;
108 unsigned long flags;
109 spin_lock_irqsave(&uid_lock, flags);
110 entry = find_uid_stat(uid);
111 if (entry) {
112 spin_unlock_irqrestore(&uid_lock, flags);
113 return entry;
114 }
115 entry = create_stat(uid);
116 spin_unlock_irqrestore(&uid_lock, flags);
117 if (entry)
118 create_stat_proc(entry);
119 return entry;
120 }
121
uid_stat_tcp_snd(uid_t uid,int size)122 int uid_stat_tcp_snd(uid_t uid, int size) {
123 struct uid_stat *entry;
124 activity_stats_update();
125 entry = find_or_create_uid_stat(uid);
126 if (!entry)
127 return -1;
128 atomic_add(size, &entry->tcp_snd);
129 return 0;
130 }
131
uid_stat_tcp_rcv(uid_t uid,int size)132 int uid_stat_tcp_rcv(uid_t uid, int size) {
133 struct uid_stat *entry;
134 activity_stats_update();
135 entry = find_or_create_uid_stat(uid);
136 if (!entry)
137 return -1;
138 atomic_add(size, &entry->tcp_rcv);
139 return 0;
140 }
141
uid_stat_init(void)142 static int __init uid_stat_init(void)
143 {
144 parent = proc_mkdir("uid_stat", NULL);
145 if (!parent) {
146 pr_err("uid_stat: failed to create proc entry\n");
147 return -1;
148 }
149 return 0;
150 }
151
152 __initcall(uid_stat_init);
153