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Source at commit ec7cab4cbb721bff91ec924ec691efd8daf36579 created 12 years 8 months ago. By Maarten ter Huurne, MIPS: JZ4740: A320: Updated quickstart documentation. | |
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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/module.h> |
21 | #include <linux/slab.h> |
22 | #include <linux/user_namespace.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 | char uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH; |
32 | static DEFINE_SPINLOCK(sequence_lock); |
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 | static DEFINE_MUTEX(uevent_sock_mutex); |
40 | #endif |
41 | |
42 | /* the strings here must match the enum in include/linux/kobject.h */ |
43 | static const char *kobject_actions[] = { |
44 | [KOBJ_ADD] = "add", |
45 | [KOBJ_REMOVE] = "remove", |
46 | [KOBJ_CHANGE] = "change", |
47 | [KOBJ_MOVE] = "move", |
48 | [KOBJ_ONLINE] = "online", |
49 | [KOBJ_OFFLINE] = "offline", |
50 | }; |
51 | |
52 | /** |
53 | * kobject_action_type - translate action string to numeric type |
54 | * |
55 | * @buf: buffer containing the action string, newline is ignored |
56 | * @len: length of buffer |
57 | * @type: pointer to the location to store the action type |
58 | * |
59 | * Returns 0 if the action string was recognized. |
60 | */ |
61 | int kobject_action_type(const char *buf, size_t count, |
62 | enum kobject_action *type) |
63 | { |
64 | enum kobject_action action; |
65 | int ret = -EINVAL; |
66 | |
67 | if (count && (buf[count-1] == '\n' || buf[count-1] == '\0')) |
68 | count--; |
69 | |
70 | if (!count) |
71 | goto out; |
72 | |
73 | for (action = 0; action < ARRAY_SIZE(kobject_actions); action++) { |
74 | if (strncmp(kobject_actions[action], buf, count) != 0) |
75 | continue; |
76 | if (kobject_actions[action][count] != '\0') |
77 | continue; |
78 | *type = action; |
79 | ret = 0; |
80 | break; |
81 | } |
82 | out: |
83 | return ret; |
84 | } |
85 | |
86 | #ifdef CONFIG_NET |
87 | static int kobj_bcast_filter(struct sock *dsk, struct sk_buff *skb, void *data) |
88 | { |
89 | struct kobject *kobj = data; |
90 | const struct kobj_ns_type_operations *ops; |
91 | |
92 | ops = kobj_ns_ops(kobj); |
93 | if (ops) { |
94 | const void *sock_ns, *ns; |
95 | ns = kobj->ktype->namespace(kobj); |
96 | sock_ns = ops->netlink_ns(dsk); |
97 | return sock_ns != ns; |
98 | } |
99 | |
100 | return 0; |
101 | } |
102 | #endif |
103 | |
104 | static int kobj_usermode_filter(struct kobject *kobj) |
105 | { |
106 | const struct kobj_ns_type_operations *ops; |
107 | |
108 | ops = kobj_ns_ops(kobj); |
109 | if (ops) { |
110 | const void *init_ns, *ns; |
111 | ns = kobj->ktype->namespace(kobj); |
112 | init_ns = ops->initial_ns(); |
113 | return ns != init_ns; |
114 | } |
115 | |
116 | return 0; |
117 | } |
118 | |
119 | /** |
120 | * kobject_uevent_env - send an uevent with environmental data |
121 | * |
122 | * @action: action that is happening |
123 | * @kobj: struct kobject that the action is happening to |
124 | * @envp_ext: pointer to environmental data |
125 | * |
126 | * Returns 0 if kobject_uevent_env() is completed with success or the |
127 | * corresponding error when it fails. |
128 | */ |
129 | int kobject_uevent_env(struct kobject *kobj, enum kobject_action action, |
130 | char *envp_ext[]) |
131 | { |
132 | struct kobj_uevent_env *env; |
133 | const char *action_string = kobject_actions[action]; |
134 | const char *devpath = NULL; |
135 | const char *subsystem; |
136 | struct kobject *top_kobj; |
137 | struct kset *kset; |
138 | const struct kset_uevent_ops *uevent_ops; |
139 | u64 seq; |
140 | int i = 0; |
141 | int retval = 0; |
142 | #ifdef CONFIG_NET |
143 | struct uevent_sock *ue_sk; |
144 | #endif |
145 | |
146 | pr_debug("kobject: '%s' (%p): %s\n", |
147 | kobject_name(kobj), kobj, __func__); |
148 | |
149 | /* search the kset we belong to */ |
150 | top_kobj = kobj; |
151 | while (!top_kobj->kset && top_kobj->parent) |
152 | top_kobj = top_kobj->parent; |
153 | |
154 | if (!top_kobj->kset) { |
155 | pr_debug("kobject: '%s' (%p): %s: attempted to send uevent " |
156 | "without kset!\n", kobject_name(kobj), kobj, |
157 | __func__); |
158 | return -EINVAL; |
159 | } |
160 | |
161 | kset = top_kobj->kset; |
162 | uevent_ops = kset->uevent_ops; |
163 | |
164 | /* skip the event, if uevent_suppress is set*/ |
165 | if (kobj->uevent_suppress) { |
166 | pr_debug("kobject: '%s' (%p): %s: uevent_suppress " |
167 | "caused the event to drop!\n", |
168 | kobject_name(kobj), kobj, __func__); |
169 | return 0; |
170 | } |
171 | /* skip the event, if the filter returns zero. */ |
172 | if (uevent_ops && uevent_ops->filter) |
173 | if (!uevent_ops->filter(kset, kobj)) { |
174 | pr_debug("kobject: '%s' (%p): %s: filter function " |
175 | "caused the event to drop!\n", |
176 | kobject_name(kobj), kobj, __func__); |
177 | return 0; |
178 | } |
179 | |
180 | /* originating subsystem */ |
181 | if (uevent_ops && uevent_ops->name) |
182 | subsystem = uevent_ops->name(kset, kobj); |
183 | else |
184 | subsystem = kobject_name(&kset->kobj); |
185 | if (!subsystem) { |
186 | pr_debug("kobject: '%s' (%p): %s: unset subsystem caused the " |
187 | "event to drop!\n", kobject_name(kobj), kobj, |
188 | __func__); |
189 | return 0; |
190 | } |
191 | |
192 | /* environment buffer */ |
193 | env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL); |
194 | if (!env) |
195 | return -ENOMEM; |
196 | |
197 | /* complete object path */ |
198 | devpath = kobject_get_path(kobj, GFP_KERNEL); |
199 | if (!devpath) { |
200 | retval = -ENOENT; |
201 | goto exit; |
202 | } |
203 | |
204 | /* default keys */ |
205 | retval = add_uevent_var(env, "ACTION=%s", action_string); |
206 | if (retval) |
207 | goto exit; |
208 | retval = add_uevent_var(env, "DEVPATH=%s", devpath); |
209 | if (retval) |
210 | goto exit; |
211 | retval = add_uevent_var(env, "SUBSYSTEM=%s", subsystem); |
212 | if (retval) |
213 | goto exit; |
214 | |
215 | /* keys passed in from the caller */ |
216 | if (envp_ext) { |
217 | for (i = 0; envp_ext[i]; i++) { |
218 | retval = add_uevent_var(env, "%s", envp_ext[i]); |
219 | if (retval) |
220 | goto exit; |
221 | } |
222 | } |
223 | |
224 | /* let the kset specific function add its stuff */ |
225 | if (uevent_ops && uevent_ops->uevent) { |
226 | retval = uevent_ops->uevent(kset, kobj, env); |
227 | if (retval) { |
228 | pr_debug("kobject: '%s' (%p): %s: uevent() returned " |
229 | "%d\n", kobject_name(kobj), kobj, |
230 | __func__, retval); |
231 | goto exit; |
232 | } |
233 | } |
234 | |
235 | /* |
236 | * Mark "add" and "remove" events in the object to ensure proper |
237 | * events to userspace during automatic cleanup. If the object did |
238 | * send an "add" event, "remove" will automatically generated by |
239 | * the core, if not already done by the caller. |
240 | */ |
241 | if (action == KOBJ_ADD) |
242 | kobj->state_add_uevent_sent = 1; |
243 | else if (action == KOBJ_REMOVE) |
244 | kobj->state_remove_uevent_sent = 1; |
245 | |
246 | /* we will send an event, so request a new sequence number */ |
247 | spin_lock(&sequence_lock); |
248 | seq = ++uevent_seqnum; |
249 | spin_unlock(&sequence_lock); |
250 | retval = add_uevent_var(env, "SEQNUM=%llu", (unsigned long long)seq); |
251 | if (retval) |
252 | goto exit; |
253 | |
254 | #if defined(CONFIG_NET) |
255 | /* send netlink message */ |
256 | mutex_lock(&uevent_sock_mutex); |
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 | /* allocate message with the maximum possible size */ |
263 | len = strlen(action_string) + strlen(devpath) + 2; |
264 | skb = alloc_skb(len + env->buflen, GFP_KERNEL); |
265 | if (skb) { |
266 | char *scratch; |
267 | |
268 | /* add header */ |
269 | scratch = skb_put(skb, len); |
270 | sprintf(scratch, "%s@%s", action_string, devpath); |
271 | |
272 | /* copy keys to our continuous event payload buffer */ |
273 | for (i = 0; i < env->envp_idx; i++) { |
274 | len = strlen(env->envp[i]) + 1; |
275 | scratch = skb_put(skb, len); |
276 | strcpy(scratch, env->envp[i]); |
277 | } |
278 | |
279 | NETLINK_CB(skb).dst_group = 1; |
280 | retval = netlink_broadcast_filtered(uevent_sock, skb, |
281 | 0, 1, GFP_KERNEL, |
282 | kobj_bcast_filter, |
283 | kobj); |
284 | /* ENOBUFS should be handled in userspace */ |
285 | if (retval == -ENOBUFS) |
286 | retval = 0; |
287 | } else |
288 | retval = -ENOMEM; |
289 | } |
290 | mutex_unlock(&uevent_sock_mutex); |
291 | #endif |
292 | |
293 | /* call uevent_helper, usually only enabled during early boot */ |
294 | if (uevent_helper[0] && !kobj_usermode_filter(kobj)) { |
295 | char *argv [3]; |
296 | |
297 | argv [0] = uevent_helper; |
298 | argv [1] = (char *)subsystem; |
299 | argv [2] = NULL; |
300 | retval = add_uevent_var(env, "HOME=/"); |
301 | if (retval) |
302 | goto exit; |
303 | retval = add_uevent_var(env, |
304 | "PATH=/sbin:/bin:/usr/sbin:/usr/bin"); |
305 | if (retval) |
306 | goto exit; |
307 | |
308 | retval = call_usermodehelper(argv[0], argv, |
309 | env->envp, UMH_WAIT_EXEC); |
310 | } |
311 | |
312 | exit: |
313 | kfree(devpath); |
314 | kfree(env); |
315 | return retval; |
316 | } |
317 | EXPORT_SYMBOL_GPL(kobject_uevent_env); |
318 | |
319 | /** |
320 | * kobject_uevent - notify userspace by sending an uevent |
321 | * |
322 | * @action: action that is happening |
323 | * @kobj: struct kobject that the action is happening to |
324 | * |
325 | * Returns 0 if kobject_uevent() is completed with success or the |
326 | * corresponding error when it fails. |
327 | */ |
328 | int kobject_uevent(struct kobject *kobj, enum kobject_action action) |
329 | { |
330 | return kobject_uevent_env(kobj, action, NULL); |
331 | } |
332 | EXPORT_SYMBOL_GPL(kobject_uevent); |
333 | |
334 | /** |
335 | * add_uevent_var - add key value string to the environment buffer |
336 | * @env: environment buffer structure |
337 | * @format: printf format for the key=value pair |
338 | * |
339 | * Returns 0 if environment variable was added successfully or -ENOMEM |
340 | * if no space was available. |
341 | */ |
342 | int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...) |
343 | { |
344 | va_list args; |
345 | int len; |
346 | |
347 | if (env->envp_idx >= ARRAY_SIZE(env->envp)) { |
348 | WARN(1, KERN_ERR "add_uevent_var: too many keys\n"); |
349 | return -ENOMEM; |
350 | } |
351 | |
352 | va_start(args, format); |
353 | len = vsnprintf(&env->buf[env->buflen], |
354 | sizeof(env->buf) - env->buflen, |
355 | format, args); |
356 | va_end(args); |
357 | |
358 | if (len >= (sizeof(env->buf) - env->buflen)) { |
359 | WARN(1, KERN_ERR "add_uevent_var: buffer size too small\n"); |
360 | return -ENOMEM; |
361 | } |
362 | |
363 | env->envp[env->envp_idx++] = &env->buf[env->buflen]; |
364 | env->buflen += len + 1; |
365 | return 0; |
366 | } |
367 | EXPORT_SYMBOL_GPL(add_uevent_var); |
368 | |
369 | #if defined(CONFIG_NET) |
370 | static int uevent_net_init(struct net *net) |
371 | { |
372 | struct uevent_sock *ue_sk; |
373 | |
374 | ue_sk = kzalloc(sizeof(*ue_sk), GFP_KERNEL); |
375 | if (!ue_sk) |
376 | return -ENOMEM; |
377 | |
378 | ue_sk->sk = netlink_kernel_create(net, NETLINK_KOBJECT_UEVENT, |
379 | 1, NULL, NULL, THIS_MODULE); |
380 | if (!ue_sk->sk) { |
381 | printk(KERN_ERR |
382 | "kobject_uevent: unable to create netlink socket!\n"); |
383 | kfree(ue_sk); |
384 | return -ENODEV; |
385 | } |
386 | mutex_lock(&uevent_sock_mutex); |
387 | list_add_tail(&ue_sk->list, &uevent_sock_list); |
388 | mutex_unlock(&uevent_sock_mutex); |
389 | return 0; |
390 | } |
391 | |
392 | static void uevent_net_exit(struct net *net) |
393 | { |
394 | struct uevent_sock *ue_sk; |
395 | |
396 | mutex_lock(&uevent_sock_mutex); |
397 | list_for_each_entry(ue_sk, &uevent_sock_list, list) { |
398 | if (sock_net(ue_sk->sk) == net) |
399 | goto found; |
400 | } |
401 | mutex_unlock(&uevent_sock_mutex); |
402 | return; |
403 | |
404 | found: |
405 | list_del(&ue_sk->list); |
406 | mutex_unlock(&uevent_sock_mutex); |
407 | |
408 | netlink_kernel_release(ue_sk->sk); |
409 | kfree(ue_sk); |
410 | } |
411 | |
412 | static struct pernet_operations uevent_net_ops = { |
413 | .init = uevent_net_init, |
414 | .exit = uevent_net_exit, |
415 | }; |
416 | |
417 | static int __init kobject_uevent_init(void) |
418 | { |
419 | netlink_set_nonroot(NETLINK_KOBJECT_UEVENT, NL_NONROOT_RECV); |
420 | return register_pernet_subsys(&uevent_net_ops); |
421 | } |
422 | |
423 | |
424 | postcore_initcall(kobject_uevent_init); |
425 | #endif |
426 |
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