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