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c757249a SN |
1 | /* |
2 | * taskstats.c - Export per-task statistics to userland | |
3 | * | |
4 | * Copyright (C) Shailabh Nagar, IBM Corp. 2006 | |
5 | * (C) Balbir Singh, IBM Corp. 2006 | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License as published by | |
9 | * the Free Software Foundation; either version 2 of the License, or | |
10 | * (at your option) any later version. | |
11 | * | |
12 | * This program is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | * GNU General Public License for more details. | |
16 | * | |
17 | */ | |
18 | ||
19 | #include <linux/kernel.h> | |
20 | #include <linux/taskstats_kern.h> | |
6f44993f | 21 | #include <linux/delayacct.h> |
c757249a SN |
22 | #include <net/genetlink.h> |
23 | #include <asm/atomic.h> | |
24 | ||
25 | static DEFINE_PER_CPU(__u32, taskstats_seqnum) = { 0 }; | |
26 | static int family_registered; | |
27 | kmem_cache_t *taskstats_cache; | |
c757249a SN |
28 | |
29 | static struct genl_family family = { | |
30 | .id = GENL_ID_GENERATE, | |
31 | .name = TASKSTATS_GENL_NAME, | |
32 | .version = TASKSTATS_GENL_VERSION, | |
33 | .maxattr = TASKSTATS_CMD_ATTR_MAX, | |
34 | }; | |
35 | ||
36 | static struct nla_policy taskstats_cmd_get_policy[TASKSTATS_CMD_ATTR_MAX+1] | |
37 | __read_mostly = { | |
38 | [TASKSTATS_CMD_ATTR_PID] = { .type = NLA_U32 }, | |
39 | [TASKSTATS_CMD_ATTR_TGID] = { .type = NLA_U32 }, | |
40 | }; | |
41 | ||
42 | ||
43 | static int prepare_reply(struct genl_info *info, u8 cmd, struct sk_buff **skbp, | |
44 | void **replyp, size_t size) | |
45 | { | |
46 | struct sk_buff *skb; | |
47 | void *reply; | |
48 | ||
49 | /* | |
50 | * If new attributes are added, please revisit this allocation | |
51 | */ | |
52 | skb = nlmsg_new(size); | |
53 | if (!skb) | |
54 | return -ENOMEM; | |
55 | ||
56 | if (!info) { | |
57 | int seq = get_cpu_var(taskstats_seqnum)++; | |
58 | put_cpu_var(taskstats_seqnum); | |
59 | ||
60 | reply = genlmsg_put(skb, 0, seq, | |
61 | family.id, 0, 0, | |
62 | cmd, family.version); | |
63 | } else | |
64 | reply = genlmsg_put(skb, info->snd_pid, info->snd_seq, | |
65 | family.id, 0, 0, | |
66 | cmd, family.version); | |
67 | if (reply == NULL) { | |
68 | nlmsg_free(skb); | |
69 | return -EINVAL; | |
70 | } | |
71 | ||
72 | *skbp = skb; | |
73 | *replyp = reply; | |
74 | return 0; | |
75 | } | |
76 | ||
77 | static int send_reply(struct sk_buff *skb, pid_t pid, int event) | |
78 | { | |
79 | struct genlmsghdr *genlhdr = nlmsg_data((struct nlmsghdr *)skb->data); | |
80 | void *reply; | |
81 | int rc; | |
82 | ||
83 | reply = genlmsg_data(genlhdr); | |
84 | ||
85 | rc = genlmsg_end(skb, reply); | |
86 | if (rc < 0) { | |
87 | nlmsg_free(skb); | |
88 | return rc; | |
89 | } | |
90 | ||
91 | if (event == TASKSTATS_MSG_MULTICAST) | |
92 | return genlmsg_multicast(skb, pid, TASKSTATS_LISTEN_GROUP); | |
93 | return genlmsg_unicast(skb, pid); | |
94 | } | |
95 | ||
96 | static int fill_pid(pid_t pid, struct task_struct *pidtsk, | |
97 | struct taskstats *stats) | |
98 | { | |
99 | int rc; | |
100 | struct task_struct *tsk = pidtsk; | |
101 | ||
102 | if (!pidtsk) { | |
103 | read_lock(&tasklist_lock); | |
104 | tsk = find_task_by_pid(pid); | |
105 | if (!tsk) { | |
106 | read_unlock(&tasklist_lock); | |
107 | return -ESRCH; | |
108 | } | |
109 | get_task_struct(tsk); | |
110 | read_unlock(&tasklist_lock); | |
111 | } else | |
112 | get_task_struct(tsk); | |
113 | ||
114 | /* | |
115 | * Each accounting subsystem adds calls to its functions to | |
116 | * fill in relevant parts of struct taskstsats as follows | |
117 | * | |
118 | * rc = per-task-foo(stats, tsk); | |
119 | * if (rc) | |
120 | * goto err; | |
121 | */ | |
122 | ||
6f44993f SN |
123 | rc = delayacct_add_tsk(stats, tsk); |
124 | stats->version = TASKSTATS_VERSION; | |
125 | ||
126 | /* Define err: label here if needed */ | |
c757249a SN |
127 | put_task_struct(tsk); |
128 | return rc; | |
129 | ||
130 | } | |
131 | ||
132 | static int fill_tgid(pid_t tgid, struct task_struct *tgidtsk, | |
133 | struct taskstats *stats) | |
134 | { | |
135 | int rc; | |
136 | struct task_struct *tsk, *first; | |
137 | ||
138 | first = tgidtsk; | |
139 | read_lock(&tasklist_lock); | |
140 | if (!first) { | |
141 | first = find_task_by_pid(tgid); | |
142 | if (!first) { | |
143 | read_unlock(&tasklist_lock); | |
144 | return -ESRCH; | |
145 | } | |
146 | } | |
147 | tsk = first; | |
148 | do { | |
149 | /* | |
150 | * Each accounting subsystem adds calls its functions to | |
151 | * fill in relevant parts of struct taskstsats as follows | |
152 | * | |
153 | * rc = per-task-foo(stats, tsk); | |
154 | * if (rc) | |
155 | * break; | |
156 | */ | |
157 | ||
6f44993f SN |
158 | rc = delayacct_add_tsk(stats, tsk); |
159 | if (rc) | |
160 | break; | |
161 | ||
c757249a SN |
162 | } while_each_thread(first, tsk); |
163 | read_unlock(&tasklist_lock); | |
6f44993f SN |
164 | stats->version = TASKSTATS_VERSION; |
165 | ||
c757249a SN |
166 | |
167 | /* | |
168 | * Accounting subsytems can also add calls here if they don't | |
169 | * wish to aggregate statistics for per-tgid stats | |
170 | */ | |
171 | ||
172 | return rc; | |
173 | } | |
174 | ||
175 | static int taskstats_send_stats(struct sk_buff *skb, struct genl_info *info) | |
176 | { | |
177 | int rc = 0; | |
178 | struct sk_buff *rep_skb; | |
179 | struct taskstats stats; | |
180 | void *reply; | |
181 | size_t size; | |
182 | struct nlattr *na; | |
183 | ||
184 | /* | |
185 | * Size includes space for nested attributes | |
186 | */ | |
187 | size = nla_total_size(sizeof(u32)) + | |
188 | nla_total_size(sizeof(struct taskstats)) + nla_total_size(0); | |
189 | ||
190 | memset(&stats, 0, sizeof(stats)); | |
191 | rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, &reply, size); | |
192 | if (rc < 0) | |
193 | return rc; | |
194 | ||
195 | if (info->attrs[TASKSTATS_CMD_ATTR_PID]) { | |
196 | u32 pid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_PID]); | |
197 | rc = fill_pid(pid, NULL, &stats); | |
198 | if (rc < 0) | |
199 | goto err; | |
200 | ||
201 | na = nla_nest_start(rep_skb, TASKSTATS_TYPE_AGGR_PID); | |
202 | NLA_PUT_U32(rep_skb, TASKSTATS_TYPE_PID, pid); | |
203 | NLA_PUT_TYPE(rep_skb, struct taskstats, TASKSTATS_TYPE_STATS, | |
204 | stats); | |
205 | } else if (info->attrs[TASKSTATS_CMD_ATTR_TGID]) { | |
206 | u32 tgid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_TGID]); | |
207 | rc = fill_tgid(tgid, NULL, &stats); | |
208 | if (rc < 0) | |
209 | goto err; | |
210 | ||
211 | na = nla_nest_start(rep_skb, TASKSTATS_TYPE_AGGR_TGID); | |
212 | NLA_PUT_U32(rep_skb, TASKSTATS_TYPE_TGID, tgid); | |
213 | NLA_PUT_TYPE(rep_skb, struct taskstats, TASKSTATS_TYPE_STATS, | |
214 | stats); | |
215 | } else { | |
216 | rc = -EINVAL; | |
217 | goto err; | |
218 | } | |
219 | ||
220 | nla_nest_end(rep_skb, na); | |
221 | ||
222 | return send_reply(rep_skb, info->snd_pid, TASKSTATS_MSG_UNICAST); | |
223 | ||
224 | nla_put_failure: | |
225 | return genlmsg_cancel(rep_skb, reply); | |
226 | err: | |
227 | nlmsg_free(rep_skb); | |
228 | return rc; | |
229 | } | |
230 | ||
231 | /* Send pid data out on exit */ | |
232 | void taskstats_exit_send(struct task_struct *tsk, struct taskstats *tidstats, | |
233 | struct taskstats *tgidstats) | |
234 | { | |
235 | int rc; | |
236 | struct sk_buff *rep_skb; | |
237 | void *reply; | |
238 | size_t size; | |
239 | int is_thread_group; | |
240 | struct nlattr *na; | |
241 | ||
242 | if (!family_registered || !tidstats) | |
243 | return; | |
244 | ||
c757249a SN |
245 | is_thread_group = !thread_group_empty(tsk); |
246 | rc = 0; | |
247 | ||
248 | /* | |
249 | * Size includes space for nested attributes | |
250 | */ | |
251 | size = nla_total_size(sizeof(u32)) + | |
252 | nla_total_size(sizeof(struct taskstats)) + nla_total_size(0); | |
253 | ||
254 | if (is_thread_group) | |
255 | size = 2 * size; /* PID + STATS + TGID + STATS */ | |
256 | ||
257 | rc = prepare_reply(NULL, TASKSTATS_CMD_NEW, &rep_skb, &reply, size); | |
258 | if (rc < 0) | |
259 | goto ret; | |
260 | ||
261 | rc = fill_pid(tsk->pid, tsk, tidstats); | |
262 | if (rc < 0) | |
263 | goto err_skb; | |
264 | ||
265 | na = nla_nest_start(rep_skb, TASKSTATS_TYPE_AGGR_PID); | |
266 | NLA_PUT_U32(rep_skb, TASKSTATS_TYPE_PID, (u32)tsk->pid); | |
267 | NLA_PUT_TYPE(rep_skb, struct taskstats, TASKSTATS_TYPE_STATS, | |
268 | *tidstats); | |
269 | nla_nest_end(rep_skb, na); | |
270 | ||
271 | if (!is_thread_group || !tgidstats) { | |
272 | send_reply(rep_skb, 0, TASKSTATS_MSG_MULTICAST); | |
273 | goto ret; | |
274 | } | |
275 | ||
276 | rc = fill_tgid(tsk->pid, tsk, tgidstats); | |
277 | /* | |
278 | * If fill_tgid() failed then one probable reason could be that the | |
279 | * thread group leader has exited. fill_tgid() will fail, send out | |
280 | * the pid statistics collected earlier. | |
281 | */ | |
282 | if (rc < 0) { | |
283 | send_reply(rep_skb, 0, TASKSTATS_MSG_MULTICAST); | |
284 | goto ret; | |
285 | } | |
286 | ||
287 | na = nla_nest_start(rep_skb, TASKSTATS_TYPE_AGGR_TGID); | |
288 | NLA_PUT_U32(rep_skb, TASKSTATS_TYPE_TGID, (u32)tsk->tgid); | |
289 | NLA_PUT_TYPE(rep_skb, struct taskstats, TASKSTATS_TYPE_STATS, | |
290 | *tgidstats); | |
291 | nla_nest_end(rep_skb, na); | |
292 | ||
293 | send_reply(rep_skb, 0, TASKSTATS_MSG_MULTICAST); | |
294 | goto ret; | |
295 | ||
296 | nla_put_failure: | |
297 | genlmsg_cancel(rep_skb, reply); | |
298 | goto ret; | |
299 | err_skb: | |
300 | nlmsg_free(rep_skb); | |
301 | ret: | |
c757249a SN |
302 | return; |
303 | } | |
304 | ||
305 | static struct genl_ops taskstats_ops = { | |
306 | .cmd = TASKSTATS_CMD_GET, | |
307 | .doit = taskstats_send_stats, | |
308 | .policy = taskstats_cmd_get_policy, | |
309 | }; | |
310 | ||
311 | /* Needed early in initialization */ | |
312 | void __init taskstats_init_early(void) | |
313 | { | |
314 | taskstats_cache = kmem_cache_create("taskstats_cache", | |
315 | sizeof(struct taskstats), | |
316 | 0, SLAB_PANIC, NULL, NULL); | |
317 | } | |
318 | ||
319 | static int __init taskstats_init(void) | |
320 | { | |
321 | int rc; | |
322 | ||
323 | rc = genl_register_family(&family); | |
324 | if (rc) | |
325 | return rc; | |
326 | ||
327 | rc = genl_register_ops(&family, &taskstats_ops); | |
328 | if (rc < 0) | |
329 | goto err; | |
330 | ||
331 | family_registered = 1; | |
332 | return 0; | |
333 | err: | |
334 | genl_unregister_family(&family); | |
335 | return rc; | |
336 | } | |
337 | ||
338 | /* | |
339 | * late initcall ensures initialization of statistics collection | |
340 | * mechanisms precedes initialization of the taskstats interface | |
341 | */ | |
342 | late_initcall(taskstats_init); |