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/export.h>
21 #include <linux/kmod.h>
22 #include <linux/slab.h>
23 #include <linux/user_namespace.h>
24 #include <linux/socket.h>
25 #include <linux/skbuff.h>
26 #include <linux/netlink.h>
28 #include <net/net_namespace.h>
32 #ifdef CONFIG_UEVENT_HELPER
33 char uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH;
37 struct list_head list;
40 static LIST_HEAD(uevent_sock_list);
43 /* This lock protects uevent_seqnum and uevent_sock_list */
44 static DEFINE_MUTEX(uevent_sock_mutex);
46 /* the strings here must match the enum in include/linux/kobject.h */
47 static const char *kobject_actions[] = {
49 [KOBJ_REMOVE] = "remove",
50 [KOBJ_CHANGE] = "change",
52 [KOBJ_ONLINE] = "online",
53 [KOBJ_OFFLINE] = "offline",
57 * kobject_action_type - translate action string to numeric type
59 * @buf: buffer containing the action string, newline is ignored
60 * @len: length of buffer
61 * @type: pointer to the location to store the action type
63 * Returns 0 if the action string was recognized.
65 int kobject_action_type(const char *buf, size_t count,
66 enum kobject_action *type)
68 enum kobject_action action;
71 if (count && (buf[count-1] == '\n' || buf[count-1] == '\0'))
77 for (action = 0; action < ARRAY_SIZE(kobject_actions); action++) {
78 if (strncmp(kobject_actions[action], buf, count) != 0)
80 if (kobject_actions[action][count] != '\0')
91 static int kobj_bcast_filter(struct sock *dsk, struct sk_buff *skb, void *data)
93 struct kobject *kobj = data, *ksobj;
94 const struct kobj_ns_type_operations *ops;
96 ops = kobj_ns_ops(kobj);
97 if (!ops && kobj->kset) {
98 ksobj = &kobj->kset->kobj;
99 if (ksobj->parent != NULL)
100 ops = kobj_ns_ops(ksobj->parent);
103 if (ops && ops->netlink_ns && kobj->ktype->namespace) {
104 const void *sock_ns, *ns;
105 ns = kobj->ktype->namespace(kobj);
106 sock_ns = ops->netlink_ns(dsk);
107 return sock_ns != ns;
114 #ifdef CONFIG_UEVENT_HELPER
115 static int kobj_usermode_filter(struct kobject *kobj)
117 const struct kobj_ns_type_operations *ops;
119 ops = kobj_ns_ops(kobj);
121 const void *init_ns, *ns;
122 ns = kobj->ktype->namespace(kobj);
123 init_ns = ops->initial_ns();
124 return ns != init_ns;
130 static int init_uevent_argv(struct kobj_uevent_env *env, const char *subsystem)
134 len = strlcpy(&env->buf[env->buflen], subsystem,
135 sizeof(env->buf) - env->buflen);
136 if (len >= (sizeof(env->buf) - env->buflen)) {
137 WARN(1, KERN_ERR "init_uevent_argv: buffer size too small\n");
141 env->argv[0] = uevent_helper;
142 env->argv[1] = &env->buf[env->buflen];
145 env->buflen += len + 1;
149 static void cleanup_uevent_env(struct subprocess_info *info)
156 * kobject_uevent_env - send an uevent with environmental data
158 * @action: action that is happening
159 * @kobj: struct kobject that the action is happening to
160 * @envp_ext: pointer to environmental data
162 * Returns 0 if kobject_uevent_env() is completed with success or the
163 * corresponding error when it fails.
165 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
168 struct kobj_uevent_env *env;
169 const char *action_string = kobject_actions[action];
170 const char *devpath = NULL;
171 const char *subsystem;
172 struct kobject *top_kobj;
174 const struct kset_uevent_ops *uevent_ops;
178 struct uevent_sock *ue_sk;
181 pr_debug("kobject: '%s' (%p): %s\n",
182 kobject_name(kobj), kobj, __func__);
184 /* search the kset we belong to */
186 while (!top_kobj->kset && top_kobj->parent)
187 top_kobj = top_kobj->parent;
189 if (!top_kobj->kset) {
190 pr_debug("kobject: '%s' (%p): %s: attempted to send uevent "
191 "without kset!\n", kobject_name(kobj), kobj,
196 kset = top_kobj->kset;
197 uevent_ops = kset->uevent_ops;
199 /* skip the event, if uevent_suppress is set*/
200 if (kobj->uevent_suppress) {
201 pr_debug("kobject: '%s' (%p): %s: uevent_suppress "
202 "caused the event to drop!\n",
203 kobject_name(kobj), kobj, __func__);
206 /* skip the event, if the filter returns zero. */
207 if (uevent_ops && uevent_ops->filter)
208 if (!uevent_ops->filter(kset, kobj)) {
209 pr_debug("kobject: '%s' (%p): %s: filter function "
210 "caused the event to drop!\n",
211 kobject_name(kobj), kobj, __func__);
215 /* originating subsystem */
216 if (uevent_ops && uevent_ops->name)
217 subsystem = uevent_ops->name(kset, kobj);
219 subsystem = kobject_name(&kset->kobj);
221 pr_debug("kobject: '%s' (%p): %s: unset subsystem caused the "
222 "event to drop!\n", kobject_name(kobj), kobj,
227 /* environment buffer */
228 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
232 /* complete object path */
233 devpath = kobject_get_path(kobj, GFP_KERNEL);
240 retval = add_uevent_var(env, "ACTION=%s", action_string);
243 retval = add_uevent_var(env, "DEVPATH=%s", devpath);
246 retval = add_uevent_var(env, "SUBSYSTEM=%s", subsystem);
250 /* keys passed in from the caller */
252 for (i = 0; envp_ext[i]; i++) {
253 retval = add_uevent_var(env, "%s", envp_ext[i]);
259 /* let the kset specific function add its stuff */
260 if (uevent_ops && uevent_ops->uevent) {
261 retval = uevent_ops->uevent(kset, kobj, env);
263 pr_debug("kobject: '%s' (%p): %s: uevent() returned "
264 "%d\n", kobject_name(kobj), kobj,
271 * Mark "add" and "remove" events in the object to ensure proper
272 * events to userspace during automatic cleanup. If the object did
273 * send an "add" event, "remove" will automatically generated by
274 * the core, if not already done by the caller.
276 if (action == KOBJ_ADD)
277 kobj->state_add_uevent_sent = 1;
278 else if (action == KOBJ_REMOVE)
279 kobj->state_remove_uevent_sent = 1;
281 mutex_lock(&uevent_sock_mutex);
282 /* we will send an event, so request a new sequence number */
283 retval = add_uevent_var(env, "SEQNUM=%llu", (unsigned long long)++uevent_seqnum);
285 mutex_unlock(&uevent_sock_mutex);
289 #if defined(CONFIG_NET)
290 /* send netlink message */
291 list_for_each_entry(ue_sk, &uevent_sock_list, list) {
292 struct sock *uevent_sock = ue_sk->sk;
296 if (!netlink_has_listeners(uevent_sock, 1))
299 /* allocate message with the maximum possible size */
300 len = strlen(action_string) + strlen(devpath) + 2;
301 skb = alloc_skb(len + env->buflen, GFP_KERNEL);
306 scratch = skb_put(skb, len);
307 sprintf(scratch, "%s@%s", action_string, devpath);
309 /* copy keys to our continuous event payload buffer */
310 for (i = 0; i < env->envp_idx; i++) {
311 len = strlen(env->envp[i]) + 1;
312 scratch = skb_put(skb, len);
313 strcpy(scratch, env->envp[i]);
316 NETLINK_CB(skb).dst_group = 1;
317 retval = netlink_broadcast_filtered(uevent_sock, skb,
321 /* ENOBUFS should be handled in userspace */
322 if (retval == -ENOBUFS || retval == -ESRCH)
328 mutex_unlock(&uevent_sock_mutex);
330 #ifdef CONFIG_UEVENT_HELPER
331 /* call uevent_helper, usually only enabled during early boot */
332 if (uevent_helper[0] && !kobj_usermode_filter(kobj)) {
333 struct subprocess_info *info;
335 retval = add_uevent_var(env, "HOME=/");
338 retval = add_uevent_var(env,
339 "PATH=/sbin:/bin:/usr/sbin:/usr/bin");
342 retval = init_uevent_argv(env, subsystem);
347 info = call_usermodehelper_setup(env->argv[0], env->argv,
348 env->envp, GFP_KERNEL,
349 NULL, cleanup_uevent_env, env);
351 retval = call_usermodehelper_exec(info, UMH_NO_WAIT);
352 env = NULL; /* freed by cleanup_uevent_env */
362 EXPORT_SYMBOL_GPL(kobject_uevent_env);
365 * kobject_uevent - notify userspace by sending an uevent
367 * @action: action that is happening
368 * @kobj: struct kobject that the action is happening to
370 * Returns 0 if kobject_uevent() is completed with success or the
371 * corresponding error when it fails.
373 int kobject_uevent(struct kobject *kobj, enum kobject_action action)
375 return kobject_uevent_env(kobj, action, NULL);
377 EXPORT_SYMBOL_GPL(kobject_uevent);
380 * add_uevent_var - add key value string to the environment buffer
381 * @env: environment buffer structure
382 * @format: printf format for the key=value pair
384 * Returns 0 if environment variable was added successfully or -ENOMEM
385 * if no space was available.
387 int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
392 if (env->envp_idx >= ARRAY_SIZE(env->envp)) {
393 WARN(1, KERN_ERR "add_uevent_var: too many keys\n");
397 va_start(args, format);
398 len = vsnprintf(&env->buf[env->buflen],
399 sizeof(env->buf) - env->buflen,
403 if (len >= (sizeof(env->buf) - env->buflen)) {
404 WARN(1, KERN_ERR "add_uevent_var: buffer size too small\n");
408 env->envp[env->envp_idx++] = &env->buf[env->buflen];
409 env->buflen += len + 1;
412 EXPORT_SYMBOL_GPL(add_uevent_var);
414 #if defined(CONFIG_NET)
415 static int uevent_net_init(struct net *net)
417 struct uevent_sock *ue_sk;
418 struct netlink_kernel_cfg cfg = {
420 .flags = NL_CFG_F_NONROOT_RECV,
423 ue_sk = kzalloc(sizeof(*ue_sk), GFP_KERNEL);
427 ue_sk->sk = netlink_kernel_create(net, NETLINK_KOBJECT_UEVENT, &cfg);
430 "kobject_uevent: unable to create netlink socket!\n");
434 mutex_lock(&uevent_sock_mutex);
435 list_add_tail(&ue_sk->list, &uevent_sock_list);
436 mutex_unlock(&uevent_sock_mutex);
440 static void uevent_net_exit(struct net *net)
442 struct uevent_sock *ue_sk;
444 mutex_lock(&uevent_sock_mutex);
445 list_for_each_entry(ue_sk, &uevent_sock_list, list) {
446 if (sock_net(ue_sk->sk) == net)
449 mutex_unlock(&uevent_sock_mutex);
453 list_del(&ue_sk->list);
454 mutex_unlock(&uevent_sock_mutex);
456 netlink_kernel_release(ue_sk->sk);
460 static struct pernet_operations uevent_net_ops = {
461 .init = uevent_net_init,
462 .exit = uevent_net_exit,
465 static int __init kobject_uevent_init(void)
467 return register_pernet_subsys(&uevent_net_ops);
471 postcore_initcall(kobject_uevent_init);