blob: f6c2c1e7779c9c93a11133a27c57081746f5fd2c
1 | /* |
2 | * kernel userspace event delivery |
3 | * |
4 | * Copyright (C) 2004 Red Hat, Inc. All rights reserved. |
5 | * Copyright (C) 2004 Novell, Inc. All rights reserved. |
6 | * Copyright (C) 2004 IBM, Inc. All rights reserved. |
7 | * |
8 | * Licensed under the GNU GPL v2. |
9 | * |
10 | * Authors: |
11 | * Robert Love <rml@novell.com> |
12 | * Kay Sievers <kay.sievers@vrfy.org> |
13 | * Arjan van de Ven <arjanv@redhat.com> |
14 | * Greg Kroah-Hartman <greg@kroah.com> |
15 | */ |
16 | |
17 | #include <linux/spinlock.h> |
18 | #include <linux/string.h> |
19 | #include <linux/kobject.h> |
20 | #include <linux/export.h> |
21 | #include <linux/kmod.h> |
22 | #include <linux/slab.h> |
23 | #include <linux/socket.h> |
24 | #include <linux/skbuff.h> |
25 | #include <linux/netlink.h> |
26 | #include <net/sock.h> |
27 | #include <net/net_namespace.h> |
28 | |
29 | |
30 | u64 uevent_seqnum; |
31 | #ifdef CONFIG_UEVENT_HELPER |
32 | char uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH; |
33 | #endif |
34 | #ifdef CONFIG_NET |
35 | struct uevent_sock { |
36 | struct list_head list; |
37 | struct sock *sk; |
38 | }; |
39 | static LIST_HEAD(uevent_sock_list); |
40 | #endif |
41 | |
42 | /* This lock protects uevent_seqnum and uevent_sock_list */ |
43 | static DEFINE_MUTEX(uevent_sock_mutex); |
44 | |
45 | /* the strings here must match the enum in include/linux/kobject.h */ |
46 | static const char *kobject_actions[] = { |
47 | [KOBJ_ADD] = "add", |
48 | [KOBJ_REMOVE] = "remove", |
49 | [KOBJ_CHANGE] = "change", |
50 | [KOBJ_MOVE] = "move", |
51 | [KOBJ_ONLINE] = "online", |
52 | [KOBJ_OFFLINE] = "offline", |
53 | }; |
54 | |
55 | /** |
56 | * kobject_action_type - translate action string to numeric type |
57 | * |
58 | * @buf: buffer containing the action string, newline is ignored |
59 | * @len: length of buffer |
60 | * @type: pointer to the location to store the action type |
61 | * |
62 | * Returns 0 if the action string was recognized. |
63 | */ |
64 | int kobject_action_type(const char *buf, size_t count, |
65 | enum kobject_action *type) |
66 | { |
67 | enum kobject_action action; |
68 | int ret = -EINVAL; |
69 | |
70 | if (count && (buf[count-1] == '\n' || buf[count-1] == '\0')) |
71 | count--; |
72 | |
73 | if (!count) |
74 | goto out; |
75 | |
76 | for (action = 0; action < ARRAY_SIZE(kobject_actions); action++) { |
77 | if (strncmp(kobject_actions[action], buf, count) != 0) |
78 | continue; |
79 | if (kobject_actions[action][count] != '\0') |
80 | continue; |
81 | *type = action; |
82 | ret = 0; |
83 | break; |
84 | } |
85 | out: |
86 | return ret; |
87 | } |
88 | |
89 | #ifdef CONFIG_NET |
90 | static int kobj_bcast_filter(struct sock *dsk, struct sk_buff *skb, void *data) |
91 | { |
92 | struct kobject *kobj = data, *ksobj; |
93 | const struct kobj_ns_type_operations *ops; |
94 | |
95 | ops = kobj_ns_ops(kobj); |
96 | if (!ops && kobj->kset) { |
97 | ksobj = &kobj->kset->kobj; |
98 | if (ksobj->parent != NULL) |
99 | ops = kobj_ns_ops(ksobj->parent); |
100 | } |
101 | |
102 | if (ops && ops->netlink_ns && kobj->ktype->namespace) { |
103 | const void *sock_ns, *ns; |
104 | ns = kobj->ktype->namespace(kobj); |
105 | sock_ns = ops->netlink_ns(dsk); |
106 | return sock_ns != ns; |
107 | } |
108 | |
109 | return 0; |
110 | } |
111 | #endif |
112 | |
113 | #ifdef CONFIG_UEVENT_HELPER |
114 | static int kobj_usermode_filter(struct kobject *kobj) |
115 | { |
116 | const struct kobj_ns_type_operations *ops; |
117 | |
118 | ops = kobj_ns_ops(kobj); |
119 | if (ops) { |
120 | const void *init_ns, *ns; |
121 | ns = kobj->ktype->namespace(kobj); |
122 | init_ns = ops->initial_ns(); |
123 | return ns != init_ns; |
124 | } |
125 | |
126 | return 0; |
127 | } |
128 | |
129 | static int init_uevent_argv(struct kobj_uevent_env *env, const char *subsystem) |
130 | { |
131 | int len; |
132 | |
133 | len = strlcpy(&env->buf[env->buflen], subsystem, |
134 | sizeof(env->buf) - env->buflen); |
135 | if (len >= (sizeof(env->buf) - env->buflen)) { |
136 | WARN(1, KERN_ERR "init_uevent_argv: buffer size too small\n"); |
137 | return -ENOMEM; |
138 | } |
139 | |
140 | env->argv[0] = uevent_helper; |
141 | env->argv[1] = &env->buf[env->buflen]; |
142 | env->argv[2] = NULL; |
143 | |
144 | env->buflen += len + 1; |
145 | return 0; |
146 | } |
147 | |
148 | static void cleanup_uevent_env(struct subprocess_info *info) |
149 | { |
150 | kfree(info->data); |
151 | } |
152 | #endif |
153 | |
154 | /** |
155 | * kobject_uevent_env - send an uevent with environmental data |
156 | * |
157 | * @action: action that is happening |
158 | * @kobj: struct kobject that the action is happening to |
159 | * @envp_ext: pointer to environmental data |
160 | * |
161 | * Returns 0 if kobject_uevent_env() is completed with success or the |
162 | * corresponding error when it fails. |
163 | */ |
164 | int kobject_uevent_env(struct kobject *kobj, enum kobject_action action, |
165 | char *envp_ext[]) |
166 | { |
167 | struct kobj_uevent_env *env; |
168 | const char *action_string = kobject_actions[action]; |
169 | const char *devpath = NULL; |
170 | const char *subsystem; |
171 | struct kobject *top_kobj; |
172 | struct kset *kset; |
173 | const struct kset_uevent_ops *uevent_ops; |
174 | int i = 0; |
175 | int retval = 0; |
176 | #ifdef CONFIG_NET |
177 | struct uevent_sock *ue_sk; |
178 | #endif |
179 | |
180 | pr_debug("kobject: '%s' (%p): %s\n", |
181 | kobject_name(kobj), kobj, __func__); |
182 | |
183 | /* search the kset we belong to */ |
184 | top_kobj = kobj; |
185 | while (!top_kobj->kset && top_kobj->parent) |
186 | top_kobj = top_kobj->parent; |
187 | |
188 | if (!top_kobj->kset) { |
189 | pr_debug("kobject: '%s' (%p): %s: attempted to send uevent " |
190 | "without kset!\n", kobject_name(kobj), kobj, |
191 | __func__); |
192 | return -EINVAL; |
193 | } |
194 | |
195 | kset = top_kobj->kset; |
196 | uevent_ops = kset->uevent_ops; |
197 | |
198 | /* skip the event, if uevent_suppress is set*/ |
199 | if (kobj->uevent_suppress) { |
200 | pr_debug("kobject: '%s' (%p): %s: uevent_suppress " |
201 | "caused the event to drop!\n", |
202 | kobject_name(kobj), kobj, __func__); |
203 | return 0; |
204 | } |
205 | /* skip the event, if the filter returns zero. */ |
206 | if (uevent_ops && uevent_ops->filter) |
207 | if (!uevent_ops->filter(kset, kobj)) { |
208 | pr_debug("kobject: '%s' (%p): %s: filter function " |
209 | "caused the event to drop!\n", |
210 | kobject_name(kobj), kobj, __func__); |
211 | return 0; |
212 | } |
213 | |
214 | /* originating subsystem */ |
215 | if (uevent_ops && uevent_ops->name) |
216 | subsystem = uevent_ops->name(kset, kobj); |
217 | else |
218 | subsystem = kobject_name(&kset->kobj); |
219 | if (!subsystem) { |
220 | pr_debug("kobject: '%s' (%p): %s: unset subsystem caused the " |
221 | "event to drop!\n", kobject_name(kobj), kobj, |
222 | __func__); |
223 | return 0; |
224 | } |
225 | |
226 | /* environment buffer */ |
227 | env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL); |
228 | if (!env) |
229 | return -ENOMEM; |
230 | |
231 | /* complete object path */ |
232 | devpath = kobject_get_path(kobj, GFP_KERNEL); |
233 | if (!devpath) { |
234 | retval = -ENOENT; |
235 | goto exit; |
236 | } |
237 | |
238 | /* default keys */ |
239 | retval = add_uevent_var(env, "ACTION=%s", action_string); |
240 | if (retval) |
241 | goto exit; |
242 | retval = add_uevent_var(env, "DEVPATH=%s", devpath); |
243 | if (retval) |
244 | goto exit; |
245 | retval = add_uevent_var(env, "SUBSYSTEM=%s", subsystem); |
246 | if (retval) |
247 | goto exit; |
248 | |
249 | /* keys passed in from the caller */ |
250 | if (envp_ext) { |
251 | for (i = 0; envp_ext[i]; i++) { |
252 | retval = add_uevent_var(env, "%s", envp_ext[i]); |
253 | if (retval) |
254 | goto exit; |
255 | } |
256 | } |
257 | |
258 | /* let the kset specific function add its stuff */ |
259 | if (uevent_ops && uevent_ops->uevent) { |
260 | retval = uevent_ops->uevent(kset, kobj, env); |
261 | if (retval) { |
262 | pr_debug("kobject: '%s' (%p): %s: uevent() returned " |
263 | "%d\n", kobject_name(kobj), kobj, |
264 | __func__, retval); |
265 | goto exit; |
266 | } |
267 | } |
268 | |
269 | /* |
270 | * Mark "add" and "remove" events in the object to ensure proper |
271 | * events to userspace during automatic cleanup. If the object did |
272 | * send an "add" event, "remove" will automatically generated by |
273 | * the core, if not already done by the caller. |
274 | */ |
275 | if (action == KOBJ_ADD) |
276 | kobj->state_add_uevent_sent = 1; |
277 | else if (action == KOBJ_REMOVE) |
278 | kobj->state_remove_uevent_sent = 1; |
279 | |
280 | mutex_lock(&uevent_sock_mutex); |
281 | /* we will send an event, so request a new sequence number */ |
282 | retval = add_uevent_var(env, "SEQNUM=%llu", (unsigned long long)++uevent_seqnum); |
283 | if (retval) { |
284 | mutex_unlock(&uevent_sock_mutex); |
285 | goto exit; |
286 | } |
287 | |
288 | #if defined(CONFIG_NET) |
289 | /* send netlink message */ |
290 | list_for_each_entry(ue_sk, &uevent_sock_list, list) { |
291 | struct sock *uevent_sock = ue_sk->sk; |
292 | struct sk_buff *skb; |
293 | size_t len; |
294 | |
295 | if (!netlink_has_listeners(uevent_sock, 1)) |
296 | continue; |
297 | |
298 | /* allocate message with the maximum possible size */ |
299 | len = strlen(action_string) + strlen(devpath) + 2; |
300 | skb = alloc_skb(len + env->buflen, GFP_KERNEL); |
301 | if (skb) { |
302 | char *scratch; |
303 | |
304 | /* add header */ |
305 | scratch = skb_put(skb, len); |
306 | sprintf(scratch, "%s@%s", action_string, devpath); |
307 | |
308 | /* copy keys to our continuous event payload buffer */ |
309 | for (i = 0; i < env->envp_idx; i++) { |
310 | len = strlen(env->envp[i]) + 1; |
311 | scratch = skb_put(skb, len); |
312 | strcpy(scratch, env->envp[i]); |
313 | } |
314 | |
315 | NETLINK_CB(skb).dst_group = 1; |
316 | retval = netlink_broadcast_filtered(uevent_sock, skb, |
317 | 0, 1, GFP_KERNEL, |
318 | kobj_bcast_filter, |
319 | kobj); |
320 | /* ENOBUFS should be handled in userspace */ |
321 | if (retval == -ENOBUFS || retval == -ESRCH) |
322 | retval = 0; |
323 | } else |
324 | retval = -ENOMEM; |
325 | } |
326 | #endif |
327 | mutex_unlock(&uevent_sock_mutex); |
328 | |
329 | #ifdef CONFIG_UEVENT_HELPER |
330 | /* call uevent_helper, usually only enabled during early boot */ |
331 | if (uevent_helper[0] && !kobj_usermode_filter(kobj)) { |
332 | struct subprocess_info *info; |
333 | |
334 | retval = add_uevent_var(env, "HOME=/"); |
335 | if (retval) |
336 | goto exit; |
337 | retval = add_uevent_var(env, |
338 | "PATH=/sbin:/bin:/usr/sbin:/usr/bin"); |
339 | if (retval) |
340 | goto exit; |
341 | retval = init_uevent_argv(env, subsystem); |
342 | if (retval) |
343 | goto exit; |
344 | |
345 | retval = -ENOMEM; |
346 | info = call_usermodehelper_setup(env->argv[0], env->argv, |
347 | env->envp, GFP_KERNEL, |
348 | NULL, cleanup_uevent_env, env); |
349 | if (info) { |
350 | retval = call_usermodehelper_exec(info, UMH_NO_WAIT); |
351 | env = NULL; /* freed by cleanup_uevent_env */ |
352 | } |
353 | } |
354 | #endif |
355 | |
356 | exit: |
357 | kfree(devpath); |
358 | kfree(env); |
359 | return retval; |
360 | } |
361 | EXPORT_SYMBOL_GPL(kobject_uevent_env); |
362 | |
363 | /** |
364 | * kobject_uevent - notify userspace by sending an uevent |
365 | * |
366 | * @action: action that is happening |
367 | * @kobj: struct kobject that the action is happening to |
368 | * |
369 | * Returns 0 if kobject_uevent() is completed with success or the |
370 | * corresponding error when it fails. |
371 | */ |
372 | int kobject_uevent(struct kobject *kobj, enum kobject_action action) |
373 | { |
374 | return kobject_uevent_env(kobj, action, NULL); |
375 | } |
376 | EXPORT_SYMBOL_GPL(kobject_uevent); |
377 | |
378 | /** |
379 | * add_uevent_var - add key value string to the environment buffer |
380 | * @env: environment buffer structure |
381 | * @format: printf format for the key=value pair |
382 | * |
383 | * Returns 0 if environment variable was added successfully or -ENOMEM |
384 | * if no space was available. |
385 | */ |
386 | int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...) |
387 | { |
388 | va_list args; |
389 | int len; |
390 | |
391 | if (env->envp_idx >= ARRAY_SIZE(env->envp)) { |
392 | WARN(1, KERN_ERR "add_uevent_var: too many keys\n"); |
393 | return -ENOMEM; |
394 | } |
395 | |
396 | va_start(args, format); |
397 | len = vsnprintf(&env->buf[env->buflen], |
398 | sizeof(env->buf) - env->buflen, |
399 | format, args); |
400 | va_end(args); |
401 | |
402 | if (len >= (sizeof(env->buf) - env->buflen)) { |
403 | WARN(1, KERN_ERR "add_uevent_var: buffer size too small\n"); |
404 | return -ENOMEM; |
405 | } |
406 | |
407 | env->envp[env->envp_idx++] = &env->buf[env->buflen]; |
408 | env->buflen += len + 1; |
409 | return 0; |
410 | } |
411 | EXPORT_SYMBOL_GPL(add_uevent_var); |
412 | |
413 | #if defined(CONFIG_NET) |
414 | static int uevent_net_init(struct net *net) |
415 | { |
416 | struct uevent_sock *ue_sk; |
417 | struct netlink_kernel_cfg cfg = { |
418 | .groups = 1, |
419 | .flags = NL_CFG_F_NONROOT_RECV, |
420 | }; |
421 | |
422 | ue_sk = kzalloc(sizeof(*ue_sk), GFP_KERNEL); |
423 | if (!ue_sk) |
424 | return -ENOMEM; |
425 | |
426 | ue_sk->sk = netlink_kernel_create(net, NETLINK_KOBJECT_UEVENT, &cfg); |
427 | if (!ue_sk->sk) { |
428 | printk(KERN_ERR |
429 | "kobject_uevent: unable to create netlink socket!\n"); |
430 | kfree(ue_sk); |
431 | return -ENODEV; |
432 | } |
433 | mutex_lock(&uevent_sock_mutex); |
434 | list_add_tail(&ue_sk->list, &uevent_sock_list); |
435 | mutex_unlock(&uevent_sock_mutex); |
436 | return 0; |
437 | } |
438 | |
439 | static void uevent_net_exit(struct net *net) |
440 | { |
441 | struct uevent_sock *ue_sk; |
442 | |
443 | mutex_lock(&uevent_sock_mutex); |
444 | list_for_each_entry(ue_sk, &uevent_sock_list, list) { |
445 | if (sock_net(ue_sk->sk) == net) |
446 | goto found; |
447 | } |
448 | mutex_unlock(&uevent_sock_mutex); |
449 | return; |
450 | |
451 | found: |
452 | list_del(&ue_sk->list); |
453 | mutex_unlock(&uevent_sock_mutex); |
454 | |
455 | netlink_kernel_release(ue_sk->sk); |
456 | kfree(ue_sk); |
457 | } |
458 | |
459 | static struct pernet_operations uevent_net_ops = { |
460 | .init = uevent_net_init, |
461 | .exit = uevent_net_exit, |
462 | }; |
463 | |
464 | static int __init kobject_uevent_init(void) |
465 | { |
466 | return register_pernet_subsys(&uevent_net_ops); |
467 | } |
468 | |
469 | |
470 | postcore_initcall(kobject_uevent_init); |
471 | #endif |
472 |