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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/socket.h> | |
24 | #include <linux/skbuff.h> | |
25 | #include <linux/netlink.h> | |
26 | #include <linux/uuid.h> | |
27 | #include <linux/ctype.h> | |
28 | #include <net/sock.h> | |
29 | #include <net/net_namespace.h> | |
30 | ||
31 | ||
32 | u64 uevent_seqnum; | |
33 | #ifdef CONFIG_UEVENT_HELPER | |
34 | char uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH; | |
35 | #endif | |
36 | #ifdef CONFIG_NET | |
37 | struct uevent_sock { | |
38 | struct list_head list; | |
39 | struct sock *sk; | |
40 | }; | |
41 | static LIST_HEAD(uevent_sock_list); | |
42 | #endif | |
43 | ||
44 | /* This lock protects uevent_seqnum and uevent_sock_list */ | |
45 | static DEFINE_MUTEX(uevent_sock_mutex); | |
46 | ||
47 | /* the strings here must match the enum in include/linux/kobject.h */ | |
48 | static const char *kobject_actions[] = { | |
49 | [KOBJ_ADD] = "add", | |
50 | [KOBJ_REMOVE] = "remove", | |
51 | [KOBJ_CHANGE] = "change", | |
52 | [KOBJ_MOVE] = "move", | |
53 | [KOBJ_ONLINE] = "online", | |
54 | [KOBJ_OFFLINE] = "offline", | |
55 | }; | |
56 | ||
57 | static int kobject_action_type(const char *buf, size_t count, | |
58 | enum kobject_action *type, | |
59 | const char **args) | |
60 | { | |
61 | enum kobject_action action; | |
62 | size_t count_first; | |
63 | const char *args_start; | |
64 | int ret = -EINVAL; | |
65 | ||
66 | if (count && (buf[count-1] == '\n' || buf[count-1] == '\0')) | |
67 | count--; | |
68 | ||
69 | if (!count) | |
70 | goto out; | |
71 | ||
72 | args_start = strnchr(buf, count, ' '); | |
73 | if (args_start) { | |
74 | count_first = args_start - buf; | |
75 | args_start = args_start + 1; | |
76 | } else | |
77 | count_first = count; | |
78 | ||
79 | for (action = 0; action < ARRAY_SIZE(kobject_actions); action++) { | |
80 | if (strncmp(kobject_actions[action], buf, count_first) != 0) | |
81 | continue; | |
82 | if (kobject_actions[action][count_first] != '\0') | |
83 | continue; | |
84 | if (args) | |
85 | *args = args_start; | |
86 | *type = action; | |
87 | ret = 0; | |
88 | break; | |
89 | } | |
90 | out: | |
91 | return ret; | |
92 | } | |
93 | ||
94 | static const char *action_arg_word_end(const char *buf, const char *buf_end, | |
95 | char delim) | |
96 | { | |
97 | const char *next = buf; | |
98 | ||
99 | while (next <= buf_end && *next != delim) | |
100 | if (!isalnum(*next++)) | |
101 | return NULL; | |
102 | ||
103 | if (next == buf) | |
104 | return NULL; | |
105 | ||
106 | return next; | |
107 | } | |
108 | ||
109 | static int kobject_action_args(const char *buf, size_t count, | |
110 | struct kobj_uevent_env **ret_env) | |
111 | { | |
112 | struct kobj_uevent_env *env = NULL; | |
113 | const char *next, *buf_end, *key; | |
114 | int key_len; | |
115 | int r = -EINVAL; | |
116 | ||
117 | if (count && (buf[count - 1] == '\n' || buf[count - 1] == '\0')) | |
118 | count--; | |
119 | ||
120 | if (!count) | |
121 | return -EINVAL; | |
122 | ||
123 | env = kzalloc(sizeof(*env), GFP_KERNEL); | |
124 | if (!env) | |
125 | return -ENOMEM; | |
126 | ||
127 | /* first arg is UUID */ | |
128 | if (count < UUID_STRING_LEN || !uuid_is_valid(buf) || | |
129 | add_uevent_var(env, "SYNTH_UUID=%.*s", UUID_STRING_LEN, buf)) | |
130 | goto out; | |
131 | ||
132 | /* | |
133 | * the rest are custom environment variables in KEY=VALUE | |
134 | * format with ' ' delimiter between each KEY=VALUE pair | |
135 | */ | |
136 | next = buf + UUID_STRING_LEN; | |
137 | buf_end = buf + count - 1; | |
138 | ||
139 | while (next <= buf_end) { | |
140 | if (*next != ' ') | |
141 | goto out; | |
142 | ||
143 | /* skip the ' ', key must follow */ | |
144 | key = ++next; | |
145 | if (key > buf_end) | |
146 | goto out; | |
147 | ||
148 | buf = next; | |
149 | next = action_arg_word_end(buf, buf_end, '='); | |
150 | if (!next || next > buf_end || *next != '=') | |
151 | goto out; | |
152 | key_len = next - buf; | |
153 | ||
154 | /* skip the '=', value must follow */ | |
155 | if (++next > buf_end) | |
156 | goto out; | |
157 | ||
158 | buf = next; | |
159 | next = action_arg_word_end(buf, buf_end, ' '); | |
160 | if (!next) | |
161 | goto out; | |
162 | ||
163 | if (add_uevent_var(env, "SYNTH_ARG_%.*s=%.*s", | |
164 | key_len, key, (int) (next - buf), buf)) | |
165 | goto out; | |
166 | } | |
167 | ||
168 | r = 0; | |
169 | out: | |
170 | if (r) | |
171 | kfree(env); | |
172 | else | |
173 | *ret_env = env; | |
174 | return r; | |
175 | } | |
176 | ||
177 | /** | |
178 | * kobject_synth_uevent - send synthetic uevent with arguments | |
179 | * | |
180 | * @kobj: struct kobject for which synthetic uevent is to be generated | |
181 | * @buf: buffer containing action type and action args, newline is ignored | |
182 | * @count: length of buffer | |
183 | * | |
184 | * Returns 0 if kobject_synthetic_uevent() is completed with success or the | |
185 | * corresponding error when it fails. | |
186 | */ | |
187 | int kobject_synth_uevent(struct kobject *kobj, const char *buf, size_t count) | |
188 | { | |
189 | char *no_uuid_envp[] = { "SYNTH_UUID=0", NULL }; | |
190 | enum kobject_action action; | |
191 | const char *action_args; | |
192 | struct kobj_uevent_env *env; | |
193 | const char *msg = NULL, *devpath; | |
194 | int r; | |
195 | ||
196 | r = kobject_action_type(buf, count, &action, &action_args); | |
197 | if (r) { | |
198 | msg = "unknown uevent action string\n"; | |
199 | goto out; | |
200 | } | |
201 | ||
202 | if (!action_args) { | |
203 | r = kobject_uevent_env(kobj, action, no_uuid_envp); | |
204 | goto out; | |
205 | } | |
206 | ||
207 | r = kobject_action_args(action_args, | |
208 | count - (action_args - buf), &env); | |
209 | if (r == -EINVAL) { | |
210 | msg = "incorrect uevent action arguments\n"; | |
211 | goto out; | |
212 | } | |
213 | ||
214 | if (r) | |
215 | goto out; | |
216 | ||
217 | r = kobject_uevent_env(kobj, action, env->envp); | |
218 | kfree(env); | |
219 | out: | |
220 | if (r) { | |
221 | devpath = kobject_get_path(kobj, GFP_KERNEL); | |
222 | printk(KERN_WARNING "synth uevent: %s: %s", | |
223 | devpath ?: "unknown device", | |
224 | msg ?: "failed to send uevent"); | |
225 | kfree(devpath); | |
226 | } | |
227 | return r; | |
228 | } | |
229 | ||
230 | #ifdef CONFIG_NET | |
231 | static int kobj_bcast_filter(struct sock *dsk, struct sk_buff *skb, void *data) | |
232 | { | |
233 | struct kobject *kobj = data, *ksobj; | |
234 | const struct kobj_ns_type_operations *ops; | |
235 | ||
236 | ops = kobj_ns_ops(kobj); | |
237 | if (!ops && kobj->kset) { | |
238 | ksobj = &kobj->kset->kobj; | |
239 | if (ksobj->parent != NULL) | |
240 | ops = kobj_ns_ops(ksobj->parent); | |
241 | } | |
242 | ||
243 | if (ops && ops->netlink_ns && kobj->ktype->namespace) { | |
244 | const void *sock_ns, *ns; | |
245 | ns = kobj->ktype->namespace(kobj); | |
246 | sock_ns = ops->netlink_ns(dsk); | |
247 | return sock_ns != ns; | |
248 | } | |
249 | ||
250 | return 0; | |
251 | } | |
252 | #endif | |
253 | ||
254 | #ifdef CONFIG_UEVENT_HELPER | |
255 | static int kobj_usermode_filter(struct kobject *kobj) | |
256 | { | |
257 | const struct kobj_ns_type_operations *ops; | |
258 | ||
259 | ops = kobj_ns_ops(kobj); | |
260 | if (ops) { | |
261 | const void *init_ns, *ns; | |
262 | ns = kobj->ktype->namespace(kobj); | |
263 | init_ns = ops->initial_ns(); | |
264 | return ns != init_ns; | |
265 | } | |
266 | ||
267 | return 0; | |
268 | } | |
269 | ||
270 | static int init_uevent_argv(struct kobj_uevent_env *env, const char *subsystem) | |
271 | { | |
272 | int len; | |
273 | ||
274 | len = strlcpy(&env->buf[env->buflen], subsystem, | |
275 | sizeof(env->buf) - env->buflen); | |
276 | if (len >= (sizeof(env->buf) - env->buflen)) { | |
277 | WARN(1, KERN_ERR "init_uevent_argv: buffer size too small\n"); | |
278 | return -ENOMEM; | |
279 | } | |
280 | ||
281 | env->argv[0] = uevent_helper; | |
282 | env->argv[1] = &env->buf[env->buflen]; | |
283 | env->argv[2] = NULL; | |
284 | ||
285 | env->buflen += len + 1; | |
286 | return 0; | |
287 | } | |
288 | ||
289 | static void cleanup_uevent_env(struct subprocess_info *info) | |
290 | { | |
291 | kfree(info->data); | |
292 | } | |
293 | #endif | |
294 | ||
295 | /** | |
296 | * kobject_uevent_env - send an uevent with environmental data | |
297 | * | |
298 | * @kobj: struct kobject that the action is happening to | |
299 | * @action: action that is happening | |
300 | * @envp_ext: pointer to environmental data | |
301 | * | |
302 | * Returns 0 if kobject_uevent_env() is completed with success or the | |
303 | * corresponding error when it fails. | |
304 | */ | |
305 | int kobject_uevent_env(struct kobject *kobj, enum kobject_action action, | |
306 | char *envp_ext[]) | |
307 | { | |
308 | struct kobj_uevent_env *env; | |
309 | const char *action_string = kobject_actions[action]; | |
310 | const char *devpath = NULL; | |
311 | const char *subsystem; | |
312 | struct kobject *top_kobj; | |
313 | struct kset *kset; | |
314 | const struct kset_uevent_ops *uevent_ops; | |
315 | int i = 0; | |
316 | int retval = 0; | |
317 | #ifdef CONFIG_NET | |
318 | struct uevent_sock *ue_sk; | |
319 | #endif | |
320 | ||
321 | pr_debug("kobject: '%s' (%p): %s\n", | |
322 | kobject_name(kobj), kobj, __func__); | |
323 | ||
324 | /* search the kset we belong to */ | |
325 | top_kobj = kobj; | |
326 | while (!top_kobj->kset && top_kobj->parent) | |
327 | top_kobj = top_kobj->parent; | |
328 | ||
329 | if (!top_kobj->kset) { | |
330 | pr_debug("kobject: '%s' (%p): %s: attempted to send uevent " | |
331 | "without kset!\n", kobject_name(kobj), kobj, | |
332 | __func__); | |
333 | return -EINVAL; | |
334 | } | |
335 | ||
336 | kset = top_kobj->kset; | |
337 | uevent_ops = kset->uevent_ops; | |
338 | ||
339 | /* skip the event, if uevent_suppress is set*/ | |
340 | if (kobj->uevent_suppress) { | |
341 | pr_debug("kobject: '%s' (%p): %s: uevent_suppress " | |
342 | "caused the event to drop!\n", | |
343 | kobject_name(kobj), kobj, __func__); | |
344 | return 0; | |
345 | } | |
346 | /* skip the event, if the filter returns zero. */ | |
347 | if (uevent_ops && uevent_ops->filter) | |
348 | if (!uevent_ops->filter(kset, kobj)) { | |
349 | pr_debug("kobject: '%s' (%p): %s: filter function " | |
350 | "caused the event to drop!\n", | |
351 | kobject_name(kobj), kobj, __func__); | |
352 | return 0; | |
353 | } | |
354 | ||
355 | /* originating subsystem */ | |
356 | if (uevent_ops && uevent_ops->name) | |
357 | subsystem = uevent_ops->name(kset, kobj); | |
358 | else | |
359 | subsystem = kobject_name(&kset->kobj); | |
360 | if (!subsystem) { | |
361 | pr_debug("kobject: '%s' (%p): %s: unset subsystem caused the " | |
362 | "event to drop!\n", kobject_name(kobj), kobj, | |
363 | __func__); | |
364 | return 0; | |
365 | } | |
366 | ||
367 | /* environment buffer */ | |
368 | env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL); | |
369 | if (!env) | |
370 | return -ENOMEM; | |
371 | ||
372 | /* complete object path */ | |
373 | devpath = kobject_get_path(kobj, GFP_KERNEL); | |
374 | if (!devpath) { | |
375 | retval = -ENOENT; | |
376 | goto exit; | |
377 | } | |
378 | ||
379 | /* default keys */ | |
380 | retval = add_uevent_var(env, "ACTION=%s", action_string); | |
381 | if (retval) | |
382 | goto exit; | |
383 | retval = add_uevent_var(env, "DEVPATH=%s", devpath); | |
384 | if (retval) | |
385 | goto exit; | |
386 | retval = add_uevent_var(env, "SUBSYSTEM=%s", subsystem); | |
387 | if (retval) | |
388 | goto exit; | |
389 | ||
390 | /* keys passed in from the caller */ | |
391 | if (envp_ext) { | |
392 | for (i = 0; envp_ext[i]; i++) { | |
393 | retval = add_uevent_var(env, "%s", envp_ext[i]); | |
394 | if (retval) | |
395 | goto exit; | |
396 | } | |
397 | } | |
398 | ||
399 | /* let the kset specific function add its stuff */ | |
400 | if (uevent_ops && uevent_ops->uevent) { | |
401 | retval = uevent_ops->uevent(kset, kobj, env); | |
402 | if (retval) { | |
403 | pr_debug("kobject: '%s' (%p): %s: uevent() returned " | |
404 | "%d\n", kobject_name(kobj), kobj, | |
405 | __func__, retval); | |
406 | goto exit; | |
407 | } | |
408 | } | |
409 | ||
410 | /* | |
411 | * Mark "add" and "remove" events in the object to ensure proper | |
412 | * events to userspace during automatic cleanup. If the object did | |
413 | * send an "add" event, "remove" will automatically generated by | |
414 | * the core, if not already done by the caller. | |
415 | */ | |
416 | if (action == KOBJ_ADD) | |
417 | kobj->state_add_uevent_sent = 1; | |
418 | else if (action == KOBJ_REMOVE) | |
419 | kobj->state_remove_uevent_sent = 1; | |
420 | ||
421 | mutex_lock(&uevent_sock_mutex); | |
422 | /* we will send an event, so request a new sequence number */ | |
423 | retval = add_uevent_var(env, "SEQNUM=%llu", (unsigned long long)++uevent_seqnum); | |
424 | if (retval) { | |
425 | mutex_unlock(&uevent_sock_mutex); | |
426 | goto exit; | |
427 | } | |
428 | ||
429 | #if defined(CONFIG_NET) | |
430 | /* send netlink message */ | |
431 | list_for_each_entry(ue_sk, &uevent_sock_list, list) { | |
432 | struct sock *uevent_sock = ue_sk->sk; | |
433 | struct sk_buff *skb; | |
434 | size_t len; | |
435 | ||
436 | if (!netlink_has_listeners(uevent_sock, 1)) | |
437 | continue; | |
438 | ||
439 | /* allocate message with the maximum possible size */ | |
440 | len = strlen(action_string) + strlen(devpath) + 2; | |
441 | skb = alloc_skb(len + env->buflen, GFP_KERNEL); | |
442 | if (skb) { | |
443 | char *scratch; | |
444 | ||
445 | /* add header */ | |
446 | scratch = skb_put(skb, len); | |
447 | sprintf(scratch, "%s@%s", action_string, devpath); | |
448 | ||
449 | /* copy keys to our continuous event payload buffer */ | |
450 | for (i = 0; i < env->envp_idx; i++) { | |
451 | len = strlen(env->envp[i]) + 1; | |
452 | scratch = skb_put(skb, len); | |
453 | strcpy(scratch, env->envp[i]); | |
454 | } | |
455 | ||
456 | NETLINK_CB(skb).dst_group = 1; | |
457 | retval = netlink_broadcast_filtered(uevent_sock, skb, | |
458 | 0, 1, GFP_KERNEL, | |
459 | kobj_bcast_filter, | |
460 | kobj); | |
461 | /* ENOBUFS should be handled in userspace */ | |
462 | if (retval == -ENOBUFS || retval == -ESRCH) | |
463 | retval = 0; | |
464 | } else | |
465 | retval = -ENOMEM; | |
466 | } | |
467 | #endif | |
468 | mutex_unlock(&uevent_sock_mutex); | |
469 | ||
470 | #ifdef CONFIG_UEVENT_HELPER | |
471 | /* call uevent_helper, usually only enabled during early boot */ | |
472 | if (uevent_helper[0] && !kobj_usermode_filter(kobj)) { | |
473 | struct subprocess_info *info; | |
474 | ||
475 | retval = add_uevent_var(env, "HOME=/"); | |
476 | if (retval) | |
477 | goto exit; | |
478 | retval = add_uevent_var(env, | |
479 | "PATH=/sbin:/bin:/usr/sbin:/usr/bin"); | |
480 | if (retval) | |
481 | goto exit; | |
482 | retval = init_uevent_argv(env, subsystem); | |
483 | if (retval) | |
484 | goto exit; | |
485 | ||
486 | retval = -ENOMEM; | |
487 | info = call_usermodehelper_setup(env->argv[0], env->argv, | |
488 | env->envp, GFP_KERNEL, | |
489 | NULL, cleanup_uevent_env, env); | |
490 | if (info) { | |
491 | retval = call_usermodehelper_exec(info, UMH_NO_WAIT); | |
492 | env = NULL; /* freed by cleanup_uevent_env */ | |
493 | } | |
494 | } | |
495 | #endif | |
496 | ||
497 | exit: | |
498 | kfree(devpath); | |
499 | kfree(env); | |
500 | return retval; | |
501 | } | |
502 | EXPORT_SYMBOL_GPL(kobject_uevent_env); | |
503 | ||
504 | /** | |
505 | * kobject_uevent - notify userspace by sending an uevent | |
506 | * | |
507 | * @kobj: struct kobject that the action is happening to | |
508 | * @action: action that is happening | |
509 | * | |
510 | * Returns 0 if kobject_uevent() is completed with success or the | |
511 | * corresponding error when it fails. | |
512 | */ | |
513 | int kobject_uevent(struct kobject *kobj, enum kobject_action action) | |
514 | { | |
515 | return kobject_uevent_env(kobj, action, NULL); | |
516 | } | |
517 | EXPORT_SYMBOL_GPL(kobject_uevent); | |
518 | ||
519 | /** | |
520 | * add_uevent_var - add key value string to the environment buffer | |
521 | * @env: environment buffer structure | |
522 | * @format: printf format for the key=value pair | |
523 | * | |
524 | * Returns 0 if environment variable was added successfully or -ENOMEM | |
525 | * if no space was available. | |
526 | */ | |
527 | int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...) | |
528 | { | |
529 | va_list args; | |
530 | int len; | |
531 | ||
532 | if (env->envp_idx >= ARRAY_SIZE(env->envp)) { | |
533 | WARN(1, KERN_ERR "add_uevent_var: too many keys\n"); | |
534 | return -ENOMEM; | |
535 | } | |
536 | ||
537 | va_start(args, format); | |
538 | len = vsnprintf(&env->buf[env->buflen], | |
539 | sizeof(env->buf) - env->buflen, | |
540 | format, args); | |
541 | va_end(args); | |
542 | ||
543 | if (len >= (sizeof(env->buf) - env->buflen)) { | |
544 | WARN(1, KERN_ERR "add_uevent_var: buffer size too small\n"); | |
545 | return -ENOMEM; | |
546 | } | |
547 | ||
548 | env->envp[env->envp_idx++] = &env->buf[env->buflen]; | |
549 | env->buflen += len + 1; | |
550 | return 0; | |
551 | } | |
552 | EXPORT_SYMBOL_GPL(add_uevent_var); | |
553 | ||
554 | #if defined(CONFIG_NET) | |
555 | static int uevent_net_init(struct net *net) | |
556 | { | |
557 | struct uevent_sock *ue_sk; | |
558 | struct netlink_kernel_cfg cfg = { | |
559 | .groups = 1, | |
560 | .flags = NL_CFG_F_NONROOT_RECV, | |
561 | }; | |
562 | ||
563 | ue_sk = kzalloc(sizeof(*ue_sk), GFP_KERNEL); | |
564 | if (!ue_sk) | |
565 | return -ENOMEM; | |
566 | ||
567 | ue_sk->sk = netlink_kernel_create(net, NETLINK_KOBJECT_UEVENT, &cfg); | |
568 | if (!ue_sk->sk) { | |
569 | printk(KERN_ERR | |
570 | "kobject_uevent: unable to create netlink socket!\n"); | |
571 | kfree(ue_sk); | |
572 | return -ENODEV; | |
573 | } | |
574 | mutex_lock(&uevent_sock_mutex); | |
575 | list_add_tail(&ue_sk->list, &uevent_sock_list); | |
576 | mutex_unlock(&uevent_sock_mutex); | |
577 | return 0; | |
578 | } | |
579 | ||
580 | static void uevent_net_exit(struct net *net) | |
581 | { | |
582 | struct uevent_sock *ue_sk; | |
583 | ||
584 | mutex_lock(&uevent_sock_mutex); | |
585 | list_for_each_entry(ue_sk, &uevent_sock_list, list) { | |
586 | if (sock_net(ue_sk->sk) == net) | |
587 | goto found; | |
588 | } | |
589 | mutex_unlock(&uevent_sock_mutex); | |
590 | return; | |
591 | ||
592 | found: | |
593 | list_del(&ue_sk->list); | |
594 | mutex_unlock(&uevent_sock_mutex); | |
595 | ||
596 | netlink_kernel_release(ue_sk->sk); | |
597 | kfree(ue_sk); | |
598 | } | |
599 | ||
600 | static struct pernet_operations uevent_net_ops = { | |
601 | .init = uevent_net_init, | |
602 | .exit = uevent_net_exit, | |
603 | }; | |
604 | ||
605 | static int __init kobject_uevent_init(void) | |
606 | { | |
607 | return register_pernet_subsys(&uevent_net_ops); | |
608 | } | |
609 | ||
610 | ||
611 | postcore_initcall(kobject_uevent_init); | |
612 | #endif |