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.
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>
23 #include <linux/socket.h>
24 #include <linux/skbuff.h>
25 #include <linux/netlink.h>
27 #include <net/net_namespace.h>
31 char uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH;
32 static DEFINE_SPINLOCK(sequence_lock);
35 struct list_head list;
38 static LIST_HEAD(uevent_sock_list);
39 static DEFINE_MUTEX(uevent_sock_mutex);
42 /* the strings here must match the enum in include/linux/kobject.h */
43 static const char *kobject_actions[] = {
45 [KOBJ_REMOVE] = "remove",
46 [KOBJ_CHANGE] = "change",
48 [KOBJ_ONLINE] = "online",
49 [KOBJ_OFFLINE] = "offline",
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;
67 if (count && (buf[count-1] == '\n' || buf[count-1] == '\0'))
73 for (action = 0; action < ARRAY_SIZE(kobject_actions); action++) {
74 if (strncmp(kobject_actions[action], buf, count) != 0)
76 if (kobject_actions[action][count] != '\0')
87 * kobject_uevent_env - send an uevent with environmental data
89 * @action: action that is happening
90 * @kobj: struct kobject that the action is happening to
91 * @envp_ext: pointer to environmental data
93 * Returns 0 if kobject_uevent() is completed with success or the
94 * corresponding error when it fails.
96 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
99 struct kobj_uevent_env *env;
100 const char *action_string = kobject_actions[action];
101 const char *devpath = NULL;
102 const char *subsystem;
103 struct kobject *top_kobj;
105 const struct kset_uevent_ops *uevent_ops;
110 struct uevent_sock *ue_sk;
113 pr_debug("kobject: '%s' (%p): %s\n",
114 kobject_name(kobj), kobj, __func__);
116 /* search the kset we belong to */
118 while (!top_kobj->kset && top_kobj->parent)
119 top_kobj = top_kobj->parent;
121 if (!top_kobj->kset) {
122 pr_debug("kobject: '%s' (%p): %s: attempted to send uevent "
123 "without kset!\n", kobject_name(kobj), kobj,
128 kset = top_kobj->kset;
129 uevent_ops = kset->uevent_ops;
131 /* skip the event, if uevent_suppress is set*/
132 if (kobj->uevent_suppress) {
133 pr_debug("kobject: '%s' (%p): %s: uevent_suppress "
134 "caused the event to drop!\n",
135 kobject_name(kobj), kobj, __func__);
138 /* skip the event, if the filter returns zero. */
139 if (uevent_ops && uevent_ops->filter)
140 if (!uevent_ops->filter(kset, kobj)) {
141 pr_debug("kobject: '%s' (%p): %s: filter function "
142 "caused the event to drop!\n",
143 kobject_name(kobj), kobj, __func__);
147 /* originating subsystem */
148 if (uevent_ops && uevent_ops->name)
149 subsystem = uevent_ops->name(kset, kobj);
151 subsystem = kobject_name(&kset->kobj);
153 pr_debug("kobject: '%s' (%p): %s: unset subsystem caused the "
154 "event to drop!\n", kobject_name(kobj), kobj,
159 /* environment buffer */
160 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
164 /* complete object path */
165 devpath = kobject_get_path(kobj, GFP_KERNEL);
172 retval = add_uevent_var(env, "ACTION=%s", action_string);
175 retval = add_uevent_var(env, "DEVPATH=%s", devpath);
178 retval = add_uevent_var(env, "SUBSYSTEM=%s", subsystem);
182 /* keys passed in from the caller */
184 for (i = 0; envp_ext[i]; i++) {
185 retval = add_uevent_var(env, "%s", envp_ext[i]);
191 /* let the kset specific function add its stuff */
192 if (uevent_ops && uevent_ops->uevent) {
193 retval = uevent_ops->uevent(kset, kobj, env);
195 pr_debug("kobject: '%s' (%p): %s: uevent() returned "
196 "%d\n", kobject_name(kobj), kobj,
203 * Mark "add" and "remove" events in the object to ensure proper
204 * events to userspace during automatic cleanup. If the object did
205 * send an "add" event, "remove" will automatically generated by
206 * the core, if not already done by the caller.
208 if (action == KOBJ_ADD)
209 kobj->state_add_uevent_sent = 1;
210 else if (action == KOBJ_REMOVE)
211 kobj->state_remove_uevent_sent = 1;
213 /* we will send an event, so request a new sequence number */
214 spin_lock(&sequence_lock);
215 seq = ++uevent_seqnum;
216 spin_unlock(&sequence_lock);
217 retval = add_uevent_var(env, "SEQNUM=%llu", (unsigned long long)seq);
221 #if defined(CONFIG_NET)
222 /* send netlink message */
223 mutex_lock(&uevent_sock_mutex);
224 list_for_each_entry(ue_sk, &uevent_sock_list, list) {
225 struct sock *uevent_sock = ue_sk->sk;
229 /* allocate message with the maximum possible size */
230 len = strlen(action_string) + strlen(devpath) + 2;
231 skb = alloc_skb(len + env->buflen, GFP_KERNEL);
236 scratch = skb_put(skb, len);
237 sprintf(scratch, "%s@%s", action_string, devpath);
239 /* copy keys to our continuous event payload buffer */
240 for (i = 0; i < env->envp_idx; i++) {
241 len = strlen(env->envp[i]) + 1;
242 scratch = skb_put(skb, len);
243 strcpy(scratch, env->envp[i]);
246 NETLINK_CB(skb).dst_group = 1;
247 retval = netlink_broadcast(uevent_sock, skb, 0, 1,
249 /* ENOBUFS should be handled in userspace */
250 if (retval == -ENOBUFS)
255 mutex_unlock(&uevent_sock_mutex);
258 /* call uevent_helper, usually only enabled during early boot */
259 if (uevent_helper[0]) {
262 argv [0] = uevent_helper;
263 argv [1] = (char *)subsystem;
265 retval = add_uevent_var(env, "HOME=/");
268 retval = add_uevent_var(env,
269 "PATH=/sbin:/bin:/usr/sbin:/usr/bin");
273 retval = call_usermodehelper(argv[0], argv,
274 env->envp, UMH_WAIT_EXEC);
282 EXPORT_SYMBOL_GPL(kobject_uevent_env);
285 * kobject_uevent - notify userspace by ending an uevent
287 * @action: action that is happening
288 * @kobj: struct kobject that the action is happening to
290 * Returns 0 if kobject_uevent() is completed with success or the
291 * corresponding error when it fails.
293 int kobject_uevent(struct kobject *kobj, enum kobject_action action)
295 return kobject_uevent_env(kobj, action, NULL);
297 EXPORT_SYMBOL_GPL(kobject_uevent);
300 * add_uevent_var - add key value string to the environment buffer
301 * @env: environment buffer structure
302 * @format: printf format for the key=value pair
304 * Returns 0 if environment variable was added successfully or -ENOMEM
305 * if no space was available.
307 int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
312 if (env->envp_idx >= ARRAY_SIZE(env->envp)) {
313 WARN(1, KERN_ERR "add_uevent_var: too many keys\n");
317 va_start(args, format);
318 len = vsnprintf(&env->buf[env->buflen],
319 sizeof(env->buf) - env->buflen,
323 if (len >= (sizeof(env->buf) - env->buflen)) {
324 WARN(1, KERN_ERR "add_uevent_var: buffer size too small\n");
328 env->envp[env->envp_idx++] = &env->buf[env->buflen];
329 env->buflen += len + 1;
332 EXPORT_SYMBOL_GPL(add_uevent_var);
334 #if defined(CONFIG_NET)
335 static int uevent_net_init(struct net *net)
337 struct uevent_sock *ue_sk;
339 ue_sk = kzalloc(sizeof(*ue_sk), GFP_KERNEL);
343 ue_sk->sk = netlink_kernel_create(net, NETLINK_KOBJECT_UEVENT,
344 1, NULL, NULL, THIS_MODULE);
347 "kobject_uevent: unable to create netlink socket!\n");
350 mutex_lock(&uevent_sock_mutex);
351 list_add_tail(&ue_sk->list, &uevent_sock_list);
352 mutex_unlock(&uevent_sock_mutex);
356 static void uevent_net_exit(struct net *net)
358 struct uevent_sock *ue_sk;
360 mutex_lock(&uevent_sock_mutex);
361 list_for_each_entry(ue_sk, &uevent_sock_list, list) {
362 if (sock_net(ue_sk->sk) == net)
365 mutex_unlock(&uevent_sock_mutex);
369 list_del(&ue_sk->list);
370 mutex_unlock(&uevent_sock_mutex);
372 netlink_kernel_release(ue_sk->sk);
376 static struct pernet_operations uevent_net_ops = {
377 .init = uevent_net_init,
378 .exit = uevent_net_exit,
381 static int __init kobject_uevent_init(void)
383 netlink_set_nonroot(NETLINK_KOBJECT_UEVENT, NL_NONROOT_RECV);
384 return register_pernet_subsys(&uevent_net_ops);
388 postcore_initcall(kobject_uevent_init);