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')
86 static int kobj_bcast_filter(struct sock *dsk, struct sk_buff *skb, void *data)
88 struct kobject *kobj = data;
89 const struct kobj_ns_type_operations *ops;
91 ops = kobj_ns_ops(kobj);
93 const void *sock_ns, *ns;
94 ns = kobj->ktype->namespace(kobj);
95 sock_ns = ops->netlink_ns(dsk);
103 * kobject_uevent_env - send an uevent with environmental data
105 * @action: action that is happening
106 * @kobj: struct kobject that the action is happening to
107 * @envp_ext: pointer to environmental data
109 * Returns 0 if kobject_uevent() is completed with success or the
110 * corresponding error when it fails.
112 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
115 struct kobj_uevent_env *env;
116 const char *action_string = kobject_actions[action];
117 const char *devpath = NULL;
118 const char *subsystem;
119 struct kobject *top_kobj;
121 const struct kset_uevent_ops *uevent_ops;
126 struct uevent_sock *ue_sk;
129 pr_debug("kobject: '%s' (%p): %s\n",
130 kobject_name(kobj), kobj, __func__);
132 /* search the kset we belong to */
134 while (!top_kobj->kset && top_kobj->parent)
135 top_kobj = top_kobj->parent;
137 if (!top_kobj->kset) {
138 pr_debug("kobject: '%s' (%p): %s: attempted to send uevent "
139 "without kset!\n", kobject_name(kobj), kobj,
144 kset = top_kobj->kset;
145 uevent_ops = kset->uevent_ops;
147 /* skip the event, if uevent_suppress is set*/
148 if (kobj->uevent_suppress) {
149 pr_debug("kobject: '%s' (%p): %s: uevent_suppress "
150 "caused the event to drop!\n",
151 kobject_name(kobj), kobj, __func__);
154 /* skip the event, if the filter returns zero. */
155 if (uevent_ops && uevent_ops->filter)
156 if (!uevent_ops->filter(kset, kobj)) {
157 pr_debug("kobject: '%s' (%p): %s: filter function "
158 "caused the event to drop!\n",
159 kobject_name(kobj), kobj, __func__);
163 /* originating subsystem */
164 if (uevent_ops && uevent_ops->name)
165 subsystem = uevent_ops->name(kset, kobj);
167 subsystem = kobject_name(&kset->kobj);
169 pr_debug("kobject: '%s' (%p): %s: unset subsystem caused the "
170 "event to drop!\n", kobject_name(kobj), kobj,
175 /* environment buffer */
176 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
180 /* complete object path */
181 devpath = kobject_get_path(kobj, GFP_KERNEL);
188 retval = add_uevent_var(env, "ACTION=%s", action_string);
191 retval = add_uevent_var(env, "DEVPATH=%s", devpath);
194 retval = add_uevent_var(env, "SUBSYSTEM=%s", subsystem);
198 /* keys passed in from the caller */
200 for (i = 0; envp_ext[i]; i++) {
201 retval = add_uevent_var(env, "%s", envp_ext[i]);
207 /* let the kset specific function add its stuff */
208 if (uevent_ops && uevent_ops->uevent) {
209 retval = uevent_ops->uevent(kset, kobj, env);
211 pr_debug("kobject: '%s' (%p): %s: uevent() returned "
212 "%d\n", kobject_name(kobj), kobj,
219 * Mark "add" and "remove" events in the object to ensure proper
220 * events to userspace during automatic cleanup. If the object did
221 * send an "add" event, "remove" will automatically generated by
222 * the core, if not already done by the caller.
224 if (action == KOBJ_ADD)
225 kobj->state_add_uevent_sent = 1;
226 else if (action == KOBJ_REMOVE)
227 kobj->state_remove_uevent_sent = 1;
229 /* we will send an event, so request a new sequence number */
230 spin_lock(&sequence_lock);
231 seq = ++uevent_seqnum;
232 spin_unlock(&sequence_lock);
233 retval = add_uevent_var(env, "SEQNUM=%llu", (unsigned long long)seq);
237 #if defined(CONFIG_NET)
238 /* send netlink message */
239 mutex_lock(&uevent_sock_mutex);
240 list_for_each_entry(ue_sk, &uevent_sock_list, list) {
241 struct sock *uevent_sock = ue_sk->sk;
245 /* allocate message with the maximum possible size */
246 len = strlen(action_string) + strlen(devpath) + 2;
247 skb = alloc_skb(len + env->buflen, GFP_KERNEL);
252 scratch = skb_put(skb, len);
253 sprintf(scratch, "%s@%s", action_string, devpath);
255 /* copy keys to our continuous event payload buffer */
256 for (i = 0; i < env->envp_idx; i++) {
257 len = strlen(env->envp[i]) + 1;
258 scratch = skb_put(skb, len);
259 strcpy(scratch, env->envp[i]);
262 NETLINK_CB(skb).dst_group = 1;
263 retval = netlink_broadcast_filtered(uevent_sock, skb,
267 /* ENOBUFS should be handled in userspace */
268 if (retval == -ENOBUFS)
273 mutex_unlock(&uevent_sock_mutex);
276 /* call uevent_helper, usually only enabled during early boot */
277 if (uevent_helper[0]) {
280 argv [0] = uevent_helper;
281 argv [1] = (char *)subsystem;
283 retval = add_uevent_var(env, "HOME=/");
286 retval = add_uevent_var(env,
287 "PATH=/sbin:/bin:/usr/sbin:/usr/bin");
291 retval = call_usermodehelper(argv[0], argv,
292 env->envp, UMH_WAIT_EXEC);
300 EXPORT_SYMBOL_GPL(kobject_uevent_env);
303 * kobject_uevent - notify userspace by ending an uevent
305 * @action: action that is happening
306 * @kobj: struct kobject that the action is happening to
308 * Returns 0 if kobject_uevent() is completed with success or the
309 * corresponding error when it fails.
311 int kobject_uevent(struct kobject *kobj, enum kobject_action action)
313 return kobject_uevent_env(kobj, action, NULL);
315 EXPORT_SYMBOL_GPL(kobject_uevent);
318 * add_uevent_var - add key value string to the environment buffer
319 * @env: environment buffer structure
320 * @format: printf format for the key=value pair
322 * Returns 0 if environment variable was added successfully or -ENOMEM
323 * if no space was available.
325 int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
330 if (env->envp_idx >= ARRAY_SIZE(env->envp)) {
331 WARN(1, KERN_ERR "add_uevent_var: too many keys\n");
335 va_start(args, format);
336 len = vsnprintf(&env->buf[env->buflen],
337 sizeof(env->buf) - env->buflen,
341 if (len >= (sizeof(env->buf) - env->buflen)) {
342 WARN(1, KERN_ERR "add_uevent_var: buffer size too small\n");
346 env->envp[env->envp_idx++] = &env->buf[env->buflen];
347 env->buflen += len + 1;
350 EXPORT_SYMBOL_GPL(add_uevent_var);
352 #if defined(CONFIG_NET)
353 static int uevent_net_init(struct net *net)
355 struct uevent_sock *ue_sk;
357 ue_sk = kzalloc(sizeof(*ue_sk), GFP_KERNEL);
361 ue_sk->sk = netlink_kernel_create(net, NETLINK_KOBJECT_UEVENT,
362 1, NULL, NULL, THIS_MODULE);
365 "kobject_uevent: unable to create netlink socket!\n");
368 mutex_lock(&uevent_sock_mutex);
369 list_add_tail(&ue_sk->list, &uevent_sock_list);
370 mutex_unlock(&uevent_sock_mutex);
374 static void uevent_net_exit(struct net *net)
376 struct uevent_sock *ue_sk;
378 mutex_lock(&uevent_sock_mutex);
379 list_for_each_entry(ue_sk, &uevent_sock_list, list) {
380 if (sock_net(ue_sk->sk) == net)
383 mutex_unlock(&uevent_sock_mutex);
387 list_del(&ue_sk->list);
388 mutex_unlock(&uevent_sock_mutex);
390 netlink_kernel_release(ue_sk->sk);
394 static struct pernet_operations uevent_net_ops = {
395 .init = uevent_net_init,
396 .exit = uevent_net_exit,
399 static int __init kobject_uevent_init(void)
401 netlink_set_nonroot(NETLINK_KOBJECT_UEVENT, NL_NONROOT_RECV);
402 return register_pernet_subsys(&uevent_net_ops);
406 postcore_initcall(kobject_uevent_init);