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