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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 | ||
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 | /** | |
87 | * kobject_uevent_env - send an uevent with environmental data | |
88 | * | |
89 | * @action: action that is happening | |
90 | * @kobj: struct kobject that the action is happening to | |
91 | * @envp_ext: pointer to environmental data | |
92 | * | |
93 | * Returns 0 if kobject_uevent() is completed with success or the | |
94 | * corresponding error when it fails. | |
95 | */ | |
96 | int kobject_uevent_env(struct kobject *kobj, enum kobject_action action, | |
97 | char *envp_ext[]) | |
98 | { | |
99 | struct kobj_uevent_env *env; | |
100 | const char *action_string = kobject_actions[action]; | |
101 | const char *devpath = NULL; | |
102 | const char *subsystem; | |
103 | struct kobject *top_kobj; | |
104 | struct kset *kset; | |
105 | const struct kset_uevent_ops *uevent_ops; | |
106 | u64 seq; | |
107 | int i = 0; | |
108 | int retval = 0; | |
109 | #ifdef CONFIG_NET | |
110 | struct uevent_sock *ue_sk; | |
111 | #endif | |
112 | ||
113 | pr_debug("kobject: '%s' (%p): %s\n", | |
114 | kobject_name(kobj), kobj, __func__); | |
115 | ||
116 | /* search the kset we belong to */ | |
117 | top_kobj = kobj; | |
118 | while (!top_kobj->kset && top_kobj->parent) | |
119 | top_kobj = top_kobj->parent; | |
120 | ||
121 | if (!top_kobj->kset) { | |
122 | pr_debug("kobject: '%s' (%p): %s: attempted to send uevent " | |
123 | "without kset!\n", kobject_name(kobj), kobj, | |
124 | __func__); | |
125 | return -EINVAL; | |
126 | } | |
127 | ||
128 | kset = top_kobj->kset; | |
129 | uevent_ops = kset->uevent_ops; | |
130 | ||
131 | /* skip the event, if uevent_suppress is set*/ | |
132 | if (kobj->uevent_suppress) { | |
133 | pr_debug("kobject: '%s' (%p): %s: uevent_suppress " | |
134 | "caused the event to drop!\n", | |
135 | kobject_name(kobj), kobj, __func__); | |
136 | return 0; | |
137 | } | |
138 | /* skip the event, if the filter returns zero. */ | |
139 | if (uevent_ops && uevent_ops->filter) | |
140 | if (!uevent_ops->filter(kset, kobj)) { | |
141 | pr_debug("kobject: '%s' (%p): %s: filter function " | |
142 | "caused the event to drop!\n", | |
143 | kobject_name(kobj), kobj, __func__); | |
144 | return 0; | |
145 | } | |
146 | ||
147 | /* originating subsystem */ | |
148 | if (uevent_ops && uevent_ops->name) | |
149 | subsystem = uevent_ops->name(kset, kobj); | |
150 | else | |
151 | subsystem = kobject_name(&kset->kobj); | |
152 | if (!subsystem) { | |
153 | pr_debug("kobject: '%s' (%p): %s: unset subsystem caused the " | |
154 | "event to drop!\n", kobject_name(kobj), kobj, | |
155 | __func__); | |
156 | return 0; | |
157 | } | |
158 | ||
159 | /* environment buffer */ | |
160 | env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL); | |
161 | if (!env) | |
162 | return -ENOMEM; | |
163 | ||
164 | /* complete object path */ | |
165 | devpath = kobject_get_path(kobj, GFP_KERNEL); | |
166 | if (!devpath) { | |
167 | retval = -ENOENT; | |
168 | goto exit; | |
169 | } | |
170 | ||
171 | /* default keys */ | |
172 | retval = add_uevent_var(env, "ACTION=%s", action_string); | |
173 | if (retval) | |
174 | goto exit; | |
175 | retval = add_uevent_var(env, "DEVPATH=%s", devpath); | |
176 | if (retval) | |
177 | goto exit; | |
178 | retval = add_uevent_var(env, "SUBSYSTEM=%s", subsystem); | |
179 | if (retval) | |
180 | goto exit; | |
181 | ||
182 | /* keys passed in from the caller */ | |
183 | if (envp_ext) { | |
184 | for (i = 0; envp_ext[i]; i++) { | |
185 | retval = add_uevent_var(env, "%s", envp_ext[i]); | |
186 | if (retval) | |
187 | goto exit; | |
188 | } | |
189 | } | |
190 | ||
191 | /* let the kset specific function add its stuff */ | |
192 | if (uevent_ops && uevent_ops->uevent) { | |
193 | retval = uevent_ops->uevent(kset, kobj, env); | |
194 | if (retval) { | |
195 | pr_debug("kobject: '%s' (%p): %s: uevent() returned " | |
196 | "%d\n", kobject_name(kobj), kobj, | |
197 | __func__, retval); | |
198 | goto exit; | |
199 | } | |
200 | } | |
201 | ||
202 | /* | |
203 | * Mark "add" and "remove" events in the object to ensure proper | |
204 | * events to userspace during automatic cleanup. If the object did | |
205 | * send an "add" event, "remove" will automatically generated by | |
206 | * the core, if not already done by the caller. | |
207 | */ | |
208 | if (action == KOBJ_ADD) | |
209 | kobj->state_add_uevent_sent = 1; | |
210 | else if (action == KOBJ_REMOVE) | |
211 | kobj->state_remove_uevent_sent = 1; | |
212 | ||
213 | /* we will send an event, so request a new sequence number */ | |
214 | spin_lock(&sequence_lock); | |
215 | seq = ++uevent_seqnum; | |
216 | spin_unlock(&sequence_lock); | |
217 | retval = add_uevent_var(env, "SEQNUM=%llu", (unsigned long long)seq); | |
218 | if (retval) | |
219 | goto exit; | |
220 | ||
221 | #if defined(CONFIG_NET) | |
222 | /* send netlink message */ | |
223 | mutex_lock(&uevent_sock_mutex); | |
224 | list_for_each_entry(ue_sk, &uevent_sock_list, list) { | |
225 | struct sock *uevent_sock = ue_sk->sk; | |
226 | struct sk_buff *skb; | |
227 | size_t len; | |
228 | ||
229 | /* allocate message with the maximum possible size */ | |
230 | len = strlen(action_string) + strlen(devpath) + 2; | |
231 | skb = alloc_skb(len + env->buflen, GFP_KERNEL); | |
232 | if (skb) { | |
233 | char *scratch; | |
234 | ||
235 | /* add header */ | |
236 | scratch = skb_put(skb, len); | |
237 | sprintf(scratch, "%s@%s", action_string, devpath); | |
238 | ||
239 | /* copy keys to our continuous event payload buffer */ | |
240 | for (i = 0; i < env->envp_idx; i++) { | |
241 | len = strlen(env->envp[i]) + 1; | |
242 | scratch = skb_put(skb, len); | |
243 | strcpy(scratch, env->envp[i]); | |
244 | } | |
245 | ||
246 | NETLINK_CB(skb).dst_group = 1; | |
247 | retval = netlink_broadcast(uevent_sock, skb, 0, 1, | |
248 | GFP_KERNEL); | |
249 | /* ENOBUFS should be handled in userspace */ | |
250 | if (retval == -ENOBUFS) | |
251 | retval = 0; | |
252 | } else | |
253 | retval = -ENOMEM; | |
254 | } | |
255 | mutex_unlock(&uevent_sock_mutex); | |
256 | #endif | |
257 | ||
258 | /* call uevent_helper, usually only enabled during early boot */ | |
259 | if (uevent_helper[0]) { | |
260 | char *argv [3]; | |
261 | ||
262 | argv [0] = uevent_helper; | |
263 | argv [1] = (char *)subsystem; | |
264 | argv [2] = NULL; | |
265 | retval = add_uevent_var(env, "HOME=/"); | |
266 | if (retval) | |
267 | goto exit; | |
268 | retval = add_uevent_var(env, | |
269 | "PATH=/sbin:/bin:/usr/sbin:/usr/bin"); | |
270 | if (retval) | |
271 | goto exit; | |
272 | ||
273 | retval = call_usermodehelper(argv[0], argv, | |
274 | env->envp, UMH_WAIT_EXEC); | |
275 | } | |
276 | ||
277 | exit: | |
278 | kfree(devpath); | |
279 | kfree(env); | |
280 | return retval; | |
281 | } | |
282 | EXPORT_SYMBOL_GPL(kobject_uevent_env); | |
283 | ||
284 | /** | |
285 | * kobject_uevent - notify userspace by ending an uevent | |
286 | * | |
287 | * @action: action that is happening | |
288 | * @kobj: struct kobject that the action is happening to | |
289 | * | |
290 | * Returns 0 if kobject_uevent() is completed with success or the | |
291 | * corresponding error when it fails. | |
292 | */ | |
293 | int kobject_uevent(struct kobject *kobj, enum kobject_action action) | |
294 | { | |
295 | return kobject_uevent_env(kobj, action, NULL); | |
296 | } | |
297 | EXPORT_SYMBOL_GPL(kobject_uevent); | |
298 | ||
299 | /** | |
300 | * add_uevent_var - add key value string to the environment buffer | |
301 | * @env: environment buffer structure | |
302 | * @format: printf format for the key=value pair | |
303 | * | |
304 | * Returns 0 if environment variable was added successfully or -ENOMEM | |
305 | * if no space was available. | |
306 | */ | |
307 | int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...) | |
308 | { | |
309 | va_list args; | |
310 | int len; | |
311 | ||
312 | if (env->envp_idx >= ARRAY_SIZE(env->envp)) { | |
313 | WARN(1, KERN_ERR "add_uevent_var: too many keys\n"); | |
314 | return -ENOMEM; | |
315 | } | |
316 | ||
317 | va_start(args, format); | |
318 | len = vsnprintf(&env->buf[env->buflen], | |
319 | sizeof(env->buf) - env->buflen, | |
320 | format, args); | |
321 | va_end(args); | |
322 | ||
323 | if (len >= (sizeof(env->buf) - env->buflen)) { | |
324 | WARN(1, KERN_ERR "add_uevent_var: buffer size too small\n"); | |
325 | return -ENOMEM; | |
326 | } | |
327 | ||
328 | env->envp[env->envp_idx++] = &env->buf[env->buflen]; | |
329 | env->buflen += len + 1; | |
330 | return 0; | |
331 | } | |
332 | EXPORT_SYMBOL_GPL(add_uevent_var); | |
333 | ||
334 | #if defined(CONFIG_NET) | |
335 | static int uevent_net_init(struct net *net) | |
336 | { | |
337 | struct uevent_sock *ue_sk; | |
338 | ||
339 | ue_sk = kzalloc(sizeof(*ue_sk), GFP_KERNEL); | |
340 | if (!ue_sk) | |
341 | return -ENOMEM; | |
342 | ||
343 | ue_sk->sk = netlink_kernel_create(net, NETLINK_KOBJECT_UEVENT, | |
344 | 1, NULL, NULL, THIS_MODULE); | |
345 | if (!ue_sk->sk) { | |
346 | printk(KERN_ERR | |
347 | "kobject_uevent: unable to create netlink socket!\n"); | |
348 | return -ENODEV; | |
349 | } | |
350 | mutex_lock(&uevent_sock_mutex); | |
351 | list_add_tail(&ue_sk->list, &uevent_sock_list); | |
352 | mutex_unlock(&uevent_sock_mutex); | |
353 | return 0; | |
354 | } | |
355 | ||
356 | static void uevent_net_exit(struct net *net) | |
357 | { | |
358 | struct uevent_sock *ue_sk; | |
359 | ||
360 | mutex_lock(&uevent_sock_mutex); | |
361 | list_for_each_entry(ue_sk, &uevent_sock_list, list) { | |
362 | if (sock_net(ue_sk->sk) == net) | |
363 | goto found; | |
364 | } | |
365 | mutex_unlock(&uevent_sock_mutex); | |
366 | return; | |
367 | ||
368 | found: | |
369 | list_del(&ue_sk->list); | |
370 | mutex_unlock(&uevent_sock_mutex); | |
371 | ||
372 | netlink_kernel_release(ue_sk->sk); | |
373 | kfree(ue_sk); | |
374 | } | |
375 | ||
376 | static struct pernet_operations uevent_net_ops = { | |
377 | .init = uevent_net_init, | |
378 | .exit = uevent_net_exit, | |
379 | }; | |
380 | ||
381 | static int __init kobject_uevent_init(void) | |
382 | { | |
383 | netlink_set_nonroot(NETLINK_KOBJECT_UEVENT, NL_NONROOT_RECV); | |
384 | return register_pernet_subsys(&uevent_net_ops); | |
385 | } | |
386 | ||
387 | ||
388 | postcore_initcall(kobject_uevent_init); | |
389 | #endif |