]>
Commit | Line | Data |
---|---|---|
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 | .flags = NL_CFG_F_NONROOT_RECV, | |
379 | }; | |
380 | ||
381 | ue_sk = kzalloc(sizeof(*ue_sk), GFP_KERNEL); | |
382 | if (!ue_sk) | |
383 | return -ENOMEM; | |
384 | ||
385 | ue_sk->sk = netlink_kernel_create(net, NETLINK_KOBJECT_UEVENT, | |
386 | THIS_MODULE, &cfg); | |
387 | if (!ue_sk->sk) { | |
388 | printk(KERN_ERR | |
389 | "kobject_uevent: unable to create netlink socket!\n"); | |
390 | kfree(ue_sk); | |
391 | return -ENODEV; | |
392 | } | |
393 | mutex_lock(&uevent_sock_mutex); | |
394 | list_add_tail(&ue_sk->list, &uevent_sock_list); | |
395 | mutex_unlock(&uevent_sock_mutex); | |
396 | return 0; | |
397 | } | |
398 | ||
399 | static void uevent_net_exit(struct net *net) | |
400 | { | |
401 | struct uevent_sock *ue_sk; | |
402 | ||
403 | mutex_lock(&uevent_sock_mutex); | |
404 | list_for_each_entry(ue_sk, &uevent_sock_list, list) { | |
405 | if (sock_net(ue_sk->sk) == net) | |
406 | goto found; | |
407 | } | |
408 | mutex_unlock(&uevent_sock_mutex); | |
409 | return; | |
410 | ||
411 | found: | |
412 | list_del(&ue_sk->list); | |
413 | mutex_unlock(&uevent_sock_mutex); | |
414 | ||
415 | netlink_kernel_release(ue_sk->sk); | |
416 | kfree(ue_sk); | |
417 | } | |
418 | ||
419 | static struct pernet_operations uevent_net_ops = { | |
420 | .init = uevent_net_init, | |
421 | .exit = uevent_net_exit, | |
422 | }; | |
423 | ||
424 | static int __init kobject_uevent_init(void) | |
425 | { | |
426 | return register_pernet_subsys(&uevent_net_ops); | |
427 | } | |
428 | ||
429 | ||
430 | postcore_initcall(kobject_uevent_init); | |
431 | #endif |