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                 /* if this task is exiting, we have already accounted for the
 104                  * time and power.
 105                  */
 106                 if (task->cpu_power == ULLONG_MAX)
 107                         continue;
 108                 task_cputime_adjusted(task, &utime, &stime);
 109                 uid_entry->active_utime += utime;
 110                 uid_entry->active_stime += stime;
 111                 uid_entry->active_power += task->cpu_power;
 112         }
 113         read_unlock(&tasklist_lock);
 114
 115         hash_for_each(hash_table, bkt, uid_entry, hash) {
 116                 cputime_t total_utime = uid_entry->utime +
 117                                                         uid_entry->active_utime;
 118                 cputime_t total_stime = uid_entry->stime +
 119                                                         uid_entry->active_stime;
 120                 unsigned long long total_power = uid_entry->power +
 121                                                         uid_entry->active_power;
 122                 seq_printf(m, "%d: %u %u %llu\n", uid_entry->uid,
 123                                                 cputime_to_usecs(total_utime),
 124                                                 cputime_to_usecs(total_stime),
 125                                                 total_power);
 126         }
 127
 128         mutex_unlock(&uid_lock);
 129         return 0;
 130 }
 131
 132 static int uid_stat_open(struct inode *inode, struct file *file)
 133 {
 134         return single_open(file, uid_stat_show, PDE_DATA(inode));
 135 }
 136
 137 static const struct file_operations uid_stat_fops = {
 138         .open           = uid_stat_open,
 139         .read           = seq_read,
 140         .llseek         = seq_lseek,
 141         .release        = single_release,
 142 };
 143
 144 static int uid_remove_open(struct inode *inode, struct file *file)
 145 {
 146         return single_open(file, NULL, NULL);
 147 }
 148
 149 static ssize_t uid_remove_write(struct file *file,
 150                         const char __user *buffer, size_t count, loff_t *ppos)
 151 {
 152         struct uid_entry *uid_entry;
 153         struct hlist_node *tmp;
 154         char uids[128];
 155         char *start_uid, *end_uid = NULL;
 156         long int uid_start = 0, uid_end = 0;
 157
 158         if (count >= sizeof(uids))
 159                 count = sizeof(uids) - 1;
 160
 161         if (copy_from_user(uids, buffer, count))
 162                 return -EFAULT;
 163
 164         uids[count] = '\0';
 165         end_uid = uids;
 166         start_uid = strsep(&end_uid, "-");
 167
 168         if (!start_uid || !end_uid)
 169                 return -EINVAL;
 170
 171         if (kstrtol(start_uid, 10, &uid_start) != 0 ||
 172                 kstrtol(end_uid, 10, &uid_end) != 0) {
 173                 return -EINVAL;
 174         }
 175
 176         mutex_lock(&uid_lock);
 177
 178         for (; uid_start <= uid_end; uid_start++) {
 179                 hash_for_each_possible_safe(hash_table, uid_entry, tmp,
 180                                                         hash, uid_start) {
 181                         hash_del(&uid_entry->hash);
 182                         kfree(uid_entry);
 183                 }
 184         }
 185
 186         mutex_unlock(&uid_lock);
 187         return count;
 188 }
 189
 190 static const struct file_operations uid_remove_fops = {
 191         .open           = uid_remove_open,
 192         .release        = single_release,
 193         .write          = uid_remove_write,
 194 };
 195
 196 static int process_notifier(struct notifier_block *self,
 197                         unsigned long cmd, void *v)
 198 {
 199         struct task_struct *task = v;
 200         struct uid_entry *uid_entry;
 201         cputime_t utime, stime;
 202         uid_t uid;
 203
 204         if (!task)
 205                 return NOTIFY_OK;
 206
 207         mutex_lock(&uid_lock);
 208         uid = from_kuid_munged(current_user_ns(), task_uid(task));
 209         uid_entry = find_or_register_uid(uid);
 210         if (!uid_entry) {
 211                 pr_err("%s: failed to find uid %d\n", __func__, uid);
 212                 goto exit;
 213         }
 214
 215         task_cputime_adjusted(task, &utime, &stime);
 216         uid_entry->utime += utime;
 217         uid_entry->stime += stime;
 218         uid_entry->power += task->cpu_power;
 219         task->cpu_power = ULLONG_MAX;
 220
 221 exit:
 222         mutex_unlock(&uid_lock);
 223         return NOTIFY_OK;
 224 }
 225
 226 static struct notifier_block process_notifier_block = {
 227         .notifier_call  = process_notifier,
 228 };
 229
 230 static int __init proc_uid_cputime_init(void)
 231 {
 232         hash_init(hash_table);
 233
 234         parent = proc_mkdir("uid_cputime", NULL);
 235         if (!parent) {
 236                 pr_err("%s: failed to create proc entry\n", __func__);
 237                 return -ENOMEM;
 238         }
 239
 240         proc_create_data("remove_uid_range", S_IWUGO, parent, &uid_remove_fops,
 241                                         NULL);
 242
 243         proc_create_data("show_uid_stat", S_IRUGO, parent, &uid_stat_fops,
 244                                         NULL);
 245
 246         profile_event_register(PROFILE_TASK_EXIT, &process_notifier_block);
 247
 248         return 0;
 249 }
 250
 251 early_initcall(proc_uid_cputime_init);