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