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/socket.h>
24 #include <linux/skbuff.h>
25 #include <linux/netlink.h>
27 #include <net/net_namespace.h>
31 #ifdef CONFIG_UEVENT_HELPER
32 char uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH;
36 struct list_head list;
39 static LIST_HEAD(uevent_sock_list);
42 /* This lock protects uevent_seqnum and uevent_sock_list */
43 static DEFINE_MUTEX(uevent_sock_mutex);
45 /* the strings here must match the enum in include/linux/kobject.h */
46 static const char *kobject_actions[] = {
48 [KOBJ_REMOVE] = "remove",
49 [KOBJ_CHANGE] = "change",
51 [KOBJ_ONLINE] = "online",
52 [KOBJ_OFFLINE] = "offline",
56 * kobject_action_type - translate action string to numeric type
58 * @buf: buffer containing the action string, newline is ignored
59 * @len: length of buffer
60 * @type: pointer to the location to store the action type
62 * Returns 0 if the action string was recognized.
64 int kobject_action_type(const char *buf, size_t count,
65 enum kobject_action *type)
67 enum kobject_action action;
70 if (count && (buf[count-1] == '\n' || buf[count-1] == '\0'))
76 for (action = 0; action < ARRAY_SIZE(kobject_actions); action++) {
77 if (strncmp(kobject_actions[action], buf, count) != 0)
79 if (kobject_actions[action][count] != '\0')
90 static int kobj_bcast_filter(struct sock *dsk, struct sk_buff *skb, void *data)
92 struct kobject *kobj = data, *ksobj;
93 const struct kobj_ns_type_operations *ops;
95 ops = kobj_ns_ops(kobj);
96 if (!ops && kobj->kset) {
97 ksobj = &kobj->kset->kobj;
98 if (ksobj->parent != NULL)
99 ops = kobj_ns_ops(ksobj->parent);
102 if (ops && ops->netlink_ns && kobj->ktype->namespace) {
103 const void *sock_ns, *ns;
104 ns = kobj->ktype->namespace(kobj);
105 sock_ns = ops->netlink_ns(dsk);
106 return sock_ns != ns;
113 #ifdef CONFIG_UEVENT_HELPER
114 static int kobj_usermode_filter(struct kobject *kobj)
116 const struct kobj_ns_type_operations *ops;
118 ops = kobj_ns_ops(kobj);
120 const void *init_ns, *ns;
121 ns = kobj->ktype->namespace(kobj);
122 init_ns = ops->initial_ns();
123 return ns != init_ns;
129 static int init_uevent_argv(struct kobj_uevent_env *env, const char *subsystem)
133 len = strlcpy(&env->buf[env->buflen], subsystem,
134 sizeof(env->buf) - env->buflen);
135 if (len >= (sizeof(env->buf) - env->buflen)) {
136 WARN(1, KERN_ERR "init_uevent_argv: buffer size too small\n");
140 env->argv[0] = uevent_helper;
141 env->argv[1] = &env->buf[env->buflen];
144 env->buflen += len + 1;
148 static void cleanup_uevent_env(struct subprocess_info *info)
155 * kobject_uevent_env - send an uevent with environmental data
157 * @action: action that is happening
158 * @kobj: struct kobject that the action is happening to
159 * @envp_ext: pointer to environmental data
161 * Returns 0 if kobject_uevent_env() is completed with success or the
162 * corresponding error when it fails.
164 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
167 struct kobj_uevent_env *env;
168 const char *action_string = kobject_actions[action];
169 const char *devpath = NULL;
170 const char *subsystem;
171 struct kobject *top_kobj;
173 const struct kset_uevent_ops *uevent_ops;
177 struct uevent_sock *ue_sk;
180 pr_debug("kobject: '%s' (%p): %s\n",
181 kobject_name(kobj), kobj, __func__);
183 /* search the kset we belong to */
185 while (!top_kobj->kset && top_kobj->parent)
186 top_kobj = top_kobj->parent;
188 if (!top_kobj->kset) {
189 pr_debug("kobject: '%s' (%p): %s: attempted to send uevent "
190 "without kset!\n", kobject_name(kobj), kobj,
195 kset = top_kobj->kset;
196 uevent_ops = kset->uevent_ops;
198 /* skip the event, if uevent_suppress is set*/
199 if (kobj->uevent_suppress) {
200 pr_debug("kobject: '%s' (%p): %s: uevent_suppress "
201 "caused the event to drop!\n",
202 kobject_name(kobj), kobj, __func__);
205 /* skip the event, if the filter returns zero. */
206 if (uevent_ops && uevent_ops->filter)
207 if (!uevent_ops->filter(kset, kobj)) {
208 pr_debug("kobject: '%s' (%p): %s: filter function "
209 "caused the event to drop!\n",
210 kobject_name(kobj), kobj, __func__);
214 /* originating subsystem */
215 if (uevent_ops && uevent_ops->name)
216 subsystem = uevent_ops->name(kset, kobj);
218 subsystem = kobject_name(&kset->kobj);
220 pr_debug("kobject: '%s' (%p): %s: unset subsystem caused the "
221 "event to drop!\n", kobject_name(kobj), kobj,
226 if (IS_ENABLED(CONFIG_ARCH_ROCKCHIP) &&
227 IS_ENABLED(CONFIG_FREEZER) &&
228 IS_ENABLED(CONFIG_ANDROID)) {
230 * Android healthd try to listen power_supply subsystem uevent,
231 * but which will block system from suspend on big.LITTLE system
232 * because thermal_cooling_device_unregister will called when
233 * cpufreq_exit. So ignore this uevent when suspend.
235 extern bool pm_freezing;
237 if (pm_freezing && !strcmp(subsystem, "thermal"))
241 /* environment buffer */
242 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
246 /* complete object path */
247 devpath = kobject_get_path(kobj, GFP_KERNEL);
254 retval = add_uevent_var(env, "ACTION=%s", action_string);
257 retval = add_uevent_var(env, "DEVPATH=%s", devpath);
260 retval = add_uevent_var(env, "SUBSYSTEM=%s", subsystem);
264 /* keys passed in from the caller */
266 for (i = 0; envp_ext[i]; i++) {
267 retval = add_uevent_var(env, "%s", envp_ext[i]);
273 /* let the kset specific function add its stuff */
274 if (uevent_ops && uevent_ops->uevent) {
275 retval = uevent_ops->uevent(kset, kobj, env);
277 pr_debug("kobject: '%s' (%p): %s: uevent() returned "
278 "%d\n", kobject_name(kobj), kobj,
285 * Mark "add" and "remove" events in the object to ensure proper
286 * events to userspace during automatic cleanup. If the object did
287 * send an "add" event, "remove" will automatically generated by
288 * the core, if not already done by the caller.
290 if (action == KOBJ_ADD)
291 kobj->state_add_uevent_sent = 1;
292 else if (action == KOBJ_REMOVE)
293 kobj->state_remove_uevent_sent = 1;
295 mutex_lock(&uevent_sock_mutex);
296 /* we will send an event, so request a new sequence number */
297 retval = add_uevent_var(env, "SEQNUM=%llu", (unsigned long long)++uevent_seqnum);
299 mutex_unlock(&uevent_sock_mutex);
303 #if defined(CONFIG_NET)
304 /* send netlink message */
305 list_for_each_entry(ue_sk, &uevent_sock_list, list) {
306 struct sock *uevent_sock = ue_sk->sk;
310 if (!netlink_has_listeners(uevent_sock, 1))
313 /* allocate message with the maximum possible size */
314 len = strlen(action_string) + strlen(devpath) + 2;
315 skb = alloc_skb(len + env->buflen, GFP_KERNEL);
320 scratch = skb_put(skb, len);
321 sprintf(scratch, "%s@%s", action_string, devpath);
323 /* copy keys to our continuous event payload buffer */
324 for (i = 0; i < env->envp_idx; i++) {
325 len = strlen(env->envp[i]) + 1;
326 scratch = skb_put(skb, len);
327 strcpy(scratch, env->envp[i]);
330 NETLINK_CB(skb).dst_group = 1;
331 retval = netlink_broadcast_filtered(uevent_sock, skb,
335 /* ENOBUFS should be handled in userspace */
336 if (retval == -ENOBUFS || retval == -ESRCH)
342 mutex_unlock(&uevent_sock_mutex);
344 #ifdef CONFIG_UEVENT_HELPER
345 /* call uevent_helper, usually only enabled during early boot */
346 if (uevent_helper[0] && !kobj_usermode_filter(kobj)) {
347 struct subprocess_info *info;
349 retval = add_uevent_var(env, "HOME=/");
352 retval = add_uevent_var(env,
353 "PATH=/sbin:/bin:/usr/sbin:/usr/bin");
356 retval = init_uevent_argv(env, subsystem);
361 info = call_usermodehelper_setup(env->argv[0], env->argv,
362 env->envp, GFP_KERNEL,
363 NULL, cleanup_uevent_env, env);
365 retval = call_usermodehelper_exec(info, UMH_NO_WAIT);
366 env = NULL; /* freed by cleanup_uevent_env */
376 EXPORT_SYMBOL_GPL(kobject_uevent_env);
379 * kobject_uevent - notify userspace by sending an uevent
381 * @action: action that is happening
382 * @kobj: struct kobject that the action is happening to
384 * Returns 0 if kobject_uevent() is completed with success or the
385 * corresponding error when it fails.
387 int kobject_uevent(struct kobject *kobj, enum kobject_action action)
389 return kobject_uevent_env(kobj, action, NULL);
391 EXPORT_SYMBOL_GPL(kobject_uevent);
394 * add_uevent_var - add key value string to the environment buffer
395 * @env: environment buffer structure
396 * @format: printf format for the key=value pair
398 * Returns 0 if environment variable was added successfully or -ENOMEM
399 * if no space was available.
401 int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
406 if (env->envp_idx >= ARRAY_SIZE(env->envp)) {
407 WARN(1, KERN_ERR "add_uevent_var: too many keys\n");
411 va_start(args, format);
412 len = vsnprintf(&env->buf[env->buflen],
413 sizeof(env->buf) - env->buflen,
417 if (len >= (sizeof(env->buf) - env->buflen)) {
418 WARN(1, KERN_ERR "add_uevent_var: buffer size too small\n");
422 env->envp[env->envp_idx++] = &env->buf[env->buflen];
423 env->buflen += len + 1;
426 EXPORT_SYMBOL_GPL(add_uevent_var);
428 #if defined(CONFIG_NET)
429 static int uevent_net_init(struct net *net)
431 struct uevent_sock *ue_sk;
432 struct netlink_kernel_cfg cfg = {
434 .flags = NL_CFG_F_NONROOT_RECV,
437 ue_sk = kzalloc(sizeof(*ue_sk), GFP_KERNEL);
441 ue_sk->sk = netlink_kernel_create(net, NETLINK_KOBJECT_UEVENT, &cfg);
444 "kobject_uevent: unable to create netlink socket!\n");
448 mutex_lock(&uevent_sock_mutex);
449 list_add_tail(&ue_sk->list, &uevent_sock_list);
450 mutex_unlock(&uevent_sock_mutex);
454 static void uevent_net_exit(struct net *net)
456 struct uevent_sock *ue_sk;
458 mutex_lock(&uevent_sock_mutex);
459 list_for_each_entry(ue_sk, &uevent_sock_list, list) {
460 if (sock_net(ue_sk->sk) == net)
463 mutex_unlock(&uevent_sock_mutex);
467 list_del(&ue_sk->list);
468 mutex_unlock(&uevent_sock_mutex);
470 netlink_kernel_release(ue_sk->sk);
474 static struct pernet_operations uevent_net_ops = {
475 .init = uevent_net_init,
476 .exit = uevent_net_exit,
479 static int __init kobject_uevent_init(void)
481 return register_pernet_subsys(&uevent_net_ops);
485 postcore_initcall(kobject_uevent_init);