drivers/misc/uid_cputime.c

   1 /* drivers/misc/uid_cputime.c
   2  *
   3  * Copyright (C) 2014 - 2015 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 <linux/atomic.h>
  17 #include <linux/err.h>
  18 #include <linux/hashtable.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/profile.h>
  24 #include <linux/sched.h>
  25 #include <linux/seq_file.h>
  26 #include <linux/slab.h>
  27 #include <linux/uaccess.h>
  28
  29 #define UID_HASH_BITS   10
  30 DECLARE_HASHTABLE(hash_table, UID_HASH_BITS);
  31
  32 static DEFINE_MUTEX(uid_lock);
  33 static struct proc_dir_entry *parent;
  34
  35 struct uid_entry {
  36         uid_t uid;
  37         cputime_t utime;
  38         cputime_t stime;
  39         cputime_t active_utime;
  40         cputime_t active_stime;
  41         unsigned long long active_power;
  42         unsigned long long power;
  43         struct hlist_node hash;
  44 };
  45
  46 static struct uid_entry *find_uid_entry(uid_t uid)
  47 {
  48         struct uid_entry *uid_entry;
  49         hash_for_each_possible(hash_table, uid_entry, hash, uid) {
  50                 if (uid_entry->uid == uid)
  51                         return uid_entry;
  52         }
  53         return NULL;
  54 }
  55
  56 static struct uid_entry *find_or_register_uid(uid_t uid)
  57 {
  58         struct uid_entry *uid_entry;
  59
  60         uid_entry = find_uid_entry(uid);
  61         if (uid_entry)
  62                 return uid_entry;
  63
  64         uid_entry = kzalloc(sizeof(struct uid_entry), GFP_ATOMIC);
  65         if (!uid_entry)
  66                 return NULL;
  67
  68         uid_entry->uid = uid;
  69
  70         hash_add(hash_table, &uid_entry->hash, uid);
  71
  72         return uid_entry;
  73 }
  74
  75 static int uid_stat_show(struct seq_file *m, void *v)
  76 {
  77         struct uid_entry *uid_entry;
  78         struct task_struct *task;
  79         cputime_t utime;
  80         cputime_t stime;
  81         unsigned long bkt;
  82
  83         mutex_lock(&uid_lock);
  84
  85         hash_for_each(hash_table, bkt, uid_entry, hash) {
  86                 uid_entry->active_stime = 0;
  87                 uid_entry->active_utime = 0;
  88                 uid_entry->active_power = 0;
  89         }
  90
  91         read_lock(&tasklist_lock);
  92         for_each_process(task) {
  93                 uid_entry = find_or_register_uid(from_kuid_munged(
  94                         current_user_ns(), task_uid(task)));
  95                 if (!uid_entry) {
  96                         read_unlock(&tasklist_lock);
  97                         mutex_unlock(&uid_lock);
  98                         pr_err("%s: failed to find the uid_entry for uid %d\n",
  99                                 __func__, from_kuid_munged(current_user_ns(),
 100                                 task_uid(task)));
 101                         return -ENOMEM;
 102                 }
 103                 task_cputime_adjusted(task, &utime, &stime);
 104                 uid_entry->active_utime += utime;
 105                 uid_entry->active_stime += stime;
 106                 uid_entry->active_power += task->cpu_power;
 107         }
 108         read_unlock(&tasklist_lock);
 109
 110         hash_for_each(hash_table, bkt, uid_entry, hash) {
 111                 cputime_t total_utime = uid_entry->utime +
 112                                                         uid_entry->active_utime;
 113                 cputime_t total_stime = uid_entry->stime +
 114                                                         uid_entry->active_stime;
 115                 unsigned long long total_power = uid_entry->power +
 116                                                         uid_entry->active_power;
 117                 seq_printf(m, "%d: %u %u %llu\n", uid_entry->uid,
 118                                                 cputime_to_usecs(total_utime),
 119                                                 cputime_to_usecs(total_stime),
 120                                                 total_power);
 121         }
 122
 123         mutex_unlock(&uid_lock);
 124         return 0;
 125 }
 126
 127 static int uid_stat_open(struct inode *inode, struct file *file)
 128 {
 129         return single_open(file, uid_stat_show, PDE_DATA(inode));
 130 }
 131
 132 static const struct file_operations uid_stat_fops = {
 133         .open           = uid_stat_open,
 134         .read           = seq_read,
 135         .llseek         = seq_lseek,
 136         .release        = single_release,
 137 };
 138
 139 static int uid_remove_open(struct inode *inode, struct file *file)
 140 {
 141         return single_open(file, NULL, NULL);
 142 }
 143
 144 static ssize_t uid_remove_write(struct file *file,
 145                         const char __user *buffer, size_t count, loff_t *ppos)
 146 {
 147         struct uid_entry *uid_entry;
 148         struct hlist_node *tmp;
 149         char uids[128];
 150         char *start_uid, *end_uid = NULL;
 151         long int uid_start = 0, uid_end = 0;
 152
 153         if (count >= sizeof(uids))
 154                 count = sizeof(uids) - 1;
 155
 156         if (copy_from_user(uids, buffer, count))
 157                 return -EFAULT;
 158
 159         uids[count] = '\0';
 160         end_uid = uids;
 161         start_uid = strsep(&end_uid, "-");
 162
 163         if (!start_uid || !end_uid)
 164                 return -EINVAL;
 165
 166         if (kstrtol(start_uid, 10, &uid_start) != 0 ||
 167                 kstrtol(end_uid, 10, &uid_end) != 0) {
 168                 return -EINVAL;
 169         }
 170
 171         mutex_lock(&uid_lock);
 172
 173         for (; uid_start <= uid_end; uid_start++) {
 174                 hash_for_each_possible_safe(hash_table, uid_entry, tmp,
 175                                                         hash, uid_start) {
 176                         hash_del(&uid_entry->hash);
 177                         kfree(uid_entry);
 178                 }
 179         }
 180
 181         mutex_unlock(&uid_lock);
 182         return count;
 183 }
 184
 185 static const struct file_operations uid_remove_fops = {
 186         .open           = uid_remove_open,
 187         .release        = single_release,
 188         .write          = uid_remove_write,
 189 };
 190
 191 static int process_notifier(struct notifier_block *self,
 192                         unsigned long cmd, void *v)
 193 {
 194         struct task_struct *task = v;
 195         struct uid_entry *uid_entry;
 196         cputime_t utime, stime;
 197         uid_t uid;
 198
 199         if (!task)
 200                 return NOTIFY_OK;
 201
 202         mutex_lock(&uid_lock);
 203         uid = from_kuid_munged(current_user_ns(), task_uid(task));
 204         uid_entry = find_or_register_uid(uid);
 205         if (!uid_entry) {
 206                 pr_err("%s: failed to find uid %d\n", __func__, uid);
 207                 goto exit;
 208         }
 209
 210         task_cputime_adjusted(task, &utime, &stime);
 211         uid_entry->utime += utime;
 212         uid_entry->stime += stime;
 213         uid_entry->power += task->cpu_power;
 214
 215 exit:
 216         mutex_unlock(&uid_lock);
 217         return NOTIFY_OK;
 218 }
 219
 220 static struct notifier_block process_notifier_block = {
 221         .notifier_call  = process_notifier,
 222 };
 223
 224 static int __init proc_uid_cputime_init(void)
 225 {
 226         hash_init(hash_table);
 227
 228         parent = proc_mkdir("uid_cputime", NULL);
 229         if (!parent) {
 230                 pr_err("%s: failed to create proc entry\n", __func__);
 231                 return -ENOMEM;
 232         }
 233
 234         proc_create_data("remove_uid_range", S_IWUGO, parent, &uid_remove_fops,
 235                                         NULL);
 236
 237         proc_create_data("show_uid_stat", S_IRUGO, parent, &uid_stat_fops,
 238                                         NULL);
 239
 240         profile_event_register(PROFILE_TASK_EXIT, &process_notifier_block);
 241
 242         return 0;
 243 }
 244
 245 early_initcall(proc_uid_cputime_init);