mm/memcontrol.c: suppress uninitialized-var warning with older gcc's
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / lib / kobject_uevent.c
blob70af0a7f97c0eb4801e177458d182ab6baad2767
1 /*
2 * kernel userspace event delivery
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.
8 * Licensed under the GNU GPL v2.
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>
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 #include <linux/user_namespace.h>
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>
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;
38 static LIST_HEAD(uevent_sock_list);
39 static DEFINE_MUTEX(uevent_sock_mutex);
40 #endif
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",
52 /**
53 * kobject_action_type - translate action string to numeric type
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
59 * Returns 0 if the action string was recognized.
61 int kobject_action_type(const char *buf, size_t count,
62 enum kobject_action *type)
64 enum kobject_action action;
65 int ret = -EINVAL;
67 if (count && (buf[count-1] == '\n' || buf[count-1] == '\0'))
68 count--;
70 if (!count)
71 goto out;
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;
82 out:
83 return ret;
86 #ifdef CONFIG_NET
87 static int kobj_bcast_filter(struct sock *dsk, struct sk_buff *skb, void *data)
89 struct kobject *kobj = data;
90 const struct kobj_ns_type_operations *ops;
92 ops = kobj_ns_ops(kobj);
93 if (ops) {
94 const void *sock_ns, *ns;
95 ns = kobj->ktype->namespace(kobj);
96 sock_ns = ops->netlink_ns(dsk);
97 return sock_ns != ns;
100 return 0;
102 #endif
104 static int kobj_usermode_filter(struct kobject *kobj)
106 const struct kobj_ns_type_operations *ops;
108 ops = kobj_ns_ops(kobj);
109 if (ops) {
110 const void *init_ns, *ns;
111 ns = kobj->ktype->namespace(kobj);
112 init_ns = ops->initial_ns();
113 return ns != init_ns;
116 return 0;
120 * kobject_uevent_env - send an uevent with environmental data
122 * @action: action that is happening
123 * @kobj: struct kobject that the action is happening to
124 * @envp_ext: pointer to environmental data
126 * Returns 0 if kobject_uevent_env() is completed with success or the
127 * corresponding error when it fails.
129 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
130 char *envp_ext[])
132 struct kobj_uevent_env *env;
133 const char *action_string = kobject_actions[action];
134 const char *devpath = NULL;
135 const char *subsystem;
136 struct kobject *top_kobj;
137 struct kset *kset;
138 const struct kset_uevent_ops *uevent_ops;
139 u64 seq;
140 int i = 0;
141 int retval = 0;
142 #ifdef CONFIG_NET
143 struct uevent_sock *ue_sk;
144 #endif
146 pr_debug("kobject: '%s' (%p): %s\n",
147 kobject_name(kobj), kobj, __func__);
149 /* search the kset we belong to */
150 top_kobj = kobj;
151 while (!top_kobj->kset && top_kobj->parent)
152 top_kobj = top_kobj->parent;
154 if (!top_kobj->kset) {
155 pr_debug("kobject: '%s' (%p): %s: attempted to send uevent "
156 "without kset!\n", kobject_name(kobj), kobj,
157 __func__);
158 return -EINVAL;
161 kset = top_kobj->kset;
162 uevent_ops = kset->uevent_ops;
164 /* skip the event, if uevent_suppress is set*/
165 if (kobj->uevent_suppress) {
166 pr_debug("kobject: '%s' (%p): %s: uevent_suppress "
167 "caused the event to drop!\n",
168 kobject_name(kobj), kobj, __func__);
169 return 0;
171 /* skip the event, if the filter returns zero. */
172 if (uevent_ops && uevent_ops->filter)
173 if (!uevent_ops->filter(kset, kobj)) {
174 pr_debug("kobject: '%s' (%p): %s: filter function "
175 "caused the event to drop!\n",
176 kobject_name(kobj), kobj, __func__);
177 return 0;
180 /* originating subsystem */
181 if (uevent_ops && uevent_ops->name)
182 subsystem = uevent_ops->name(kset, kobj);
183 else
184 subsystem = kobject_name(&kset->kobj);
185 if (!subsystem) {
186 pr_debug("kobject: '%s' (%p): %s: unset subsystem caused the "
187 "event to drop!\n", kobject_name(kobj), kobj,
188 __func__);
189 return 0;
192 /* environment buffer */
193 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
194 if (!env)
195 return -ENOMEM;
197 /* complete object path */
198 devpath = kobject_get_path(kobj, GFP_KERNEL);
199 if (!devpath) {
200 retval = -ENOENT;
201 goto exit;
204 /* default keys */
205 retval = add_uevent_var(env, "ACTION=%s", action_string);
206 if (retval)
207 goto exit;
208 retval = add_uevent_var(env, "DEVPATH=%s", devpath);
209 if (retval)
210 goto exit;
211 retval = add_uevent_var(env, "SUBSYSTEM=%s", subsystem);
212 if (retval)
213 goto exit;
215 /* keys passed in from the caller */
216 if (envp_ext) {
217 for (i = 0; envp_ext[i]; i++) {
218 retval = add_uevent_var(env, "%s", envp_ext[i]);
219 if (retval)
220 goto exit;
224 /* let the kset specific function add its stuff */
225 if (uevent_ops && uevent_ops->uevent) {
226 retval = uevent_ops->uevent(kset, kobj, env);
227 if (retval) {
228 pr_debug("kobject: '%s' (%p): %s: uevent() returned "
229 "%d\n", kobject_name(kobj), kobj,
230 __func__, retval);
231 goto exit;
236 * Mark "add" and "remove" events in the object to ensure proper
237 * events to userspace during automatic cleanup. If the object did
238 * send an "add" event, "remove" will automatically generated by
239 * the core, if not already done by the caller.
241 if (action == KOBJ_ADD)
242 kobj->state_add_uevent_sent = 1;
243 else if (action == KOBJ_REMOVE)
244 kobj->state_remove_uevent_sent = 1;
246 /* we will send an event, so request a new sequence number */
247 spin_lock(&sequence_lock);
248 seq = ++uevent_seqnum;
249 spin_unlock(&sequence_lock);
250 retval = add_uevent_var(env, "SEQNUM=%llu", (unsigned long long)seq);
251 if (retval)
252 goto exit;
254 #if defined(CONFIG_NET)
255 /* send netlink message */
256 mutex_lock(&uevent_sock_mutex);
257 list_for_each_entry(ue_sk, &uevent_sock_list, list) {
258 struct sock *uevent_sock = ue_sk->sk;
259 struct sk_buff *skb;
260 size_t len;
262 /* allocate message with the maximum possible size */
263 len = strlen(action_string) + strlen(devpath) + 2;
264 skb = alloc_skb(len + env->buflen, GFP_KERNEL);
265 if (skb) {
266 char *scratch;
268 /* add header */
269 scratch = skb_put(skb, len);
270 sprintf(scratch, "%s@%s", action_string, devpath);
272 /* copy keys to our continuous event payload buffer */
273 for (i = 0; i < env->envp_idx; i++) {
274 len = strlen(env->envp[i]) + 1;
275 scratch = skb_put(skb, len);
276 strcpy(scratch, env->envp[i]);
279 NETLINK_CB(skb).dst_group = 1;
280 retval = netlink_broadcast_filtered(uevent_sock, skb,
281 0, 1, GFP_KERNEL,
282 kobj_bcast_filter,
283 kobj);
284 /* ENOBUFS should be handled in userspace */
285 if (retval == -ENOBUFS)
286 retval = 0;
287 } else
288 retval = -ENOMEM;
290 mutex_unlock(&uevent_sock_mutex);
291 #endif
293 /* call uevent_helper, usually only enabled during early boot */
294 if (uevent_helper[0] && !kobj_usermode_filter(kobj)) {
295 char *argv [3];
297 argv [0] = uevent_helper;
298 argv [1] = (char *)subsystem;
299 argv [2] = NULL;
300 retval = add_uevent_var(env, "HOME=/");
301 if (retval)
302 goto exit;
303 retval = add_uevent_var(env,
304 "PATH=/sbin:/bin:/usr/sbin:/usr/bin");
305 if (retval)
306 goto exit;
308 retval = call_usermodehelper(argv[0], argv,
309 env->envp, UMH_WAIT_EXEC);
312 exit:
313 kfree(devpath);
314 kfree(env);
315 return retval;
317 EXPORT_SYMBOL_GPL(kobject_uevent_env);
320 * kobject_uevent - notify userspace by sending an uevent
322 * @action: action that is happening
323 * @kobj: struct kobject that the action is happening to
325 * Returns 0 if kobject_uevent() is completed with success or the
326 * corresponding error when it fails.
328 int kobject_uevent(struct kobject *kobj, enum kobject_action action)
330 return kobject_uevent_env(kobj, action, NULL);
332 EXPORT_SYMBOL_GPL(kobject_uevent);
335 * add_uevent_var - add key value string to the environment buffer
336 * @env: environment buffer structure
337 * @format: printf format for the key=value pair
339 * Returns 0 if environment variable was added successfully or -ENOMEM
340 * if no space was available.
342 int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
344 va_list args;
345 int len;
347 if (env->envp_idx >= ARRAY_SIZE(env->envp)) {
348 WARN(1, KERN_ERR "add_uevent_var: too many keys\n");
349 return -ENOMEM;
352 va_start(args, format);
353 len = vsnprintf(&env->buf[env->buflen],
354 sizeof(env->buf) - env->buflen,
355 format, args);
356 va_end(args);
358 if (len >= (sizeof(env->buf) - env->buflen)) {
359 WARN(1, KERN_ERR "add_uevent_var: buffer size too small\n");
360 return -ENOMEM;
363 env->envp[env->envp_idx++] = &env->buf[env->buflen];
364 env->buflen += len + 1;
365 return 0;
367 EXPORT_SYMBOL_GPL(add_uevent_var);
369 #if defined(CONFIG_NET)
370 static int uevent_net_init(struct net *net)
372 struct uevent_sock *ue_sk;
374 ue_sk = kzalloc(sizeof(*ue_sk), GFP_KERNEL);
375 if (!ue_sk)
376 return -ENOMEM;
378 ue_sk->sk = netlink_kernel_create(net, NETLINK_KOBJECT_UEVENT,
379 1, NULL, NULL, THIS_MODULE);
380 if (!ue_sk->sk) {
381 printk(KERN_ERR
382 "kobject_uevent: unable to create netlink socket!\n");
383 kfree(ue_sk);
384 return -ENODEV;
386 mutex_lock(&uevent_sock_mutex);
387 list_add_tail(&ue_sk->list, &uevent_sock_list);
388 mutex_unlock(&uevent_sock_mutex);
389 return 0;
392 static void uevent_net_exit(struct net *net)
394 struct uevent_sock *ue_sk;
396 mutex_lock(&uevent_sock_mutex);
397 list_for_each_entry(ue_sk, &uevent_sock_list, list) {
398 if (sock_net(ue_sk->sk) == net)
399 goto found;
401 mutex_unlock(&uevent_sock_mutex);
402 return;
404 found:
405 list_del(&ue_sk->list);
406 mutex_unlock(&uevent_sock_mutex);
408 netlink_kernel_release(ue_sk->sk);
409 kfree(ue_sk);
412 static struct pernet_operations uevent_net_ops = {
413 .init = uevent_net_init,
414 .exit = uevent_net_exit,
417 static int __init kobject_uevent_init(void)
419 netlink_set_nonroot(NETLINK_KOBJECT_UEVENT, NL_NONROOT_RECV);
420 return register_pernet_subsys(&uevent_net_ops);
424 postcore_initcall(kobject_uevent_init);
425 #endif