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