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>
26 #include <linux/uuid.h>
27 #include <linux/ctype.h>
29 #include <net/net_namespace.h>
33 #ifdef CONFIG_UEVENT_HELPER
34 char uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH;
38 struct list_head list;
41 static LIST_HEAD(uevent_sock_list);
44 /* This lock protects uevent_seqnum and uevent_sock_list */
45 static DEFINE_MUTEX(uevent_sock_mutex);
47 /* the strings here must match the enum in include/linux/kobject.h */
48 static const char *kobject_actions[] = {
50 [KOBJ_REMOVE] = "remove",
51 [KOBJ_CHANGE] = "change",
53 [KOBJ_ONLINE] = "online",
54 [KOBJ_OFFLINE] = "offline",
56 [KOBJ_UNBIND] = "unbind",
59 static int kobject_action_type(const char *buf, size_t count,
60 enum kobject_action *type,
63 enum kobject_action action;
65 const char *args_start;
68 if (count && (buf[count-1] == '\n' || buf[count-1] == '\0'))
74 args_start = strnchr(buf, count, ' ');
76 count_first = args_start - buf;
77 args_start = args_start + 1;
81 for (action = 0; action < ARRAY_SIZE(kobject_actions); action++) {
82 if (strncmp(kobject_actions[action], buf, count_first) != 0)
84 if (kobject_actions[action][count_first] != '\0')
96 static const char *action_arg_word_end(const char *buf, const char *buf_end,
99 const char *next = buf;
101 while (next <= buf_end && *next != delim)
102 if (!isalnum(*next++))
111 static int kobject_action_args(const char *buf, size_t count,
112 struct kobj_uevent_env **ret_env)
114 struct kobj_uevent_env *env = NULL;
115 const char *next, *buf_end, *key;
119 if (count && (buf[count - 1] == '\n' || buf[count - 1] == '\0'))
125 env = kzalloc(sizeof(*env), GFP_KERNEL);
129 /* first arg is UUID */
130 if (count < UUID_STRING_LEN || !uuid_is_valid(buf) ||
131 add_uevent_var(env, "SYNTH_UUID=%.*s", UUID_STRING_LEN, buf))
135 * the rest are custom environment variables in KEY=VALUE
136 * format with ' ' delimiter between each KEY=VALUE pair
138 next = buf + UUID_STRING_LEN;
139 buf_end = buf + count - 1;
141 while (next <= buf_end) {
145 /* skip the ' ', key must follow */
151 next = action_arg_word_end(buf, buf_end, '=');
152 if (!next || next > buf_end || *next != '=')
154 key_len = next - buf;
156 /* skip the '=', value must follow */
157 if (++next > buf_end)
161 next = action_arg_word_end(buf, buf_end, ' ');
165 if (add_uevent_var(env, "SYNTH_ARG_%.*s=%.*s",
166 key_len, key, (int) (next - buf), buf))
180 * kobject_synth_uevent - send synthetic uevent with arguments
182 * @kobj: struct kobject for which synthetic uevent is to be generated
183 * @buf: buffer containing action type and action args, newline is ignored
184 * @count: length of buffer
186 * Returns 0 if kobject_synthetic_uevent() is completed with success or the
187 * corresponding error when it fails.
189 int kobject_synth_uevent(struct kobject *kobj, const char *buf, size_t count)
191 char *no_uuid_envp[] = { "SYNTH_UUID=0", NULL };
192 enum kobject_action action;
193 const char *action_args;
194 struct kobj_uevent_env *env;
195 const char *msg = NULL, *devpath;
198 r = kobject_action_type(buf, count, &action, &action_args);
200 msg = "unknown uevent action string\n";
205 r = kobject_uevent_env(kobj, action, no_uuid_envp);
209 r = kobject_action_args(action_args,
210 count - (action_args - buf), &env);
212 msg = "incorrect uevent action arguments\n";
219 r = kobject_uevent_env(kobj, action, env->envp);
223 devpath = kobject_get_path(kobj, GFP_KERNEL);
224 printk(KERN_WARNING "synth uevent: %s: %s",
225 devpath ?: "unknown device",
226 msg ?: "failed to send uevent");
233 static int kobj_bcast_filter(struct sock *dsk, struct sk_buff *skb, void *data)
235 struct kobject *kobj = data, *ksobj;
236 const struct kobj_ns_type_operations *ops;
238 ops = kobj_ns_ops(kobj);
239 if (!ops && kobj->kset) {
240 ksobj = &kobj->kset->kobj;
241 if (ksobj->parent != NULL)
242 ops = kobj_ns_ops(ksobj->parent);
245 if (ops && ops->netlink_ns && kobj->ktype->namespace) {
246 const void *sock_ns, *ns;
247 ns = kobj->ktype->namespace(kobj);
248 sock_ns = ops->netlink_ns(dsk);
249 return sock_ns != ns;
256 #ifdef CONFIG_UEVENT_HELPER
257 static int kobj_usermode_filter(struct kobject *kobj)
259 const struct kobj_ns_type_operations *ops;
261 ops = kobj_ns_ops(kobj);
263 const void *init_ns, *ns;
264 ns = kobj->ktype->namespace(kobj);
265 init_ns = ops->initial_ns();
266 return ns != init_ns;
272 static int init_uevent_argv(struct kobj_uevent_env *env, const char *subsystem)
274 int buffer_size = sizeof(env->buf) - env->buflen;
277 len = strlcpy(&env->buf[env->buflen], subsystem, buffer_size);
278 if (len >= buffer_size) {
279 pr_warn("init_uevent_argv: buffer size of %d too small, needed %d\n",
284 env->argv[0] = uevent_helper;
285 env->argv[1] = &env->buf[env->buflen];
288 env->buflen += len + 1;
292 static void cleanup_uevent_env(struct subprocess_info *info)
298 static void zap_modalias_env(struct kobj_uevent_env *env)
300 static const char modalias_prefix[] = "MODALIAS=";
303 for (i = 0; i < env->envp_idx;) {
304 if (strncmp(env->envp[i], modalias_prefix,
305 sizeof(modalias_prefix) - 1)) {
310 if (i != env->envp_idx - 1)
311 memmove(&env->envp[i], &env->envp[i + 1],
312 sizeof(env->envp[i]) * env->envp_idx - 1);
319 * kobject_uevent_env - send an uevent with environmental data
321 * @kobj: struct kobject that the action is happening to
322 * @action: action that is happening
323 * @envp_ext: pointer to environmental data
325 * Returns 0 if kobject_uevent_env() is completed with success or the
326 * corresponding error when it fails.
328 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
331 struct kobj_uevent_env *env;
332 const char *action_string = kobject_actions[action];
333 const char *devpath = NULL;
334 const char *subsystem;
335 struct kobject *top_kobj;
337 const struct kset_uevent_ops *uevent_ops;
341 struct uevent_sock *ue_sk;
345 * Mark "remove" event done regardless of result, for some subsystems
346 * do not want to re-trigger "remove" event via automatic cleanup.
348 if (action == KOBJ_REMOVE)
349 kobj->state_remove_uevent_sent = 1;
351 pr_debug("kobject: '%s' (%p): %s\n",
352 kobject_name(kobj), kobj, __func__);
354 /* search the kset we belong to */
356 while (!top_kobj->kset && top_kobj->parent)
357 top_kobj = top_kobj->parent;
359 if (!top_kobj->kset) {
360 pr_debug("kobject: '%s' (%p): %s: attempted to send uevent "
361 "without kset!\n", kobject_name(kobj), kobj,
366 kset = top_kobj->kset;
367 uevent_ops = kset->uevent_ops;
369 /* skip the event, if uevent_suppress is set*/
370 if (kobj->uevent_suppress) {
371 pr_debug("kobject: '%s' (%p): %s: uevent_suppress "
372 "caused the event to drop!\n",
373 kobject_name(kobj), kobj, __func__);
376 /* skip the event, if the filter returns zero. */
377 if (uevent_ops && uevent_ops->filter)
378 if (!uevent_ops->filter(kset, kobj)) {
379 pr_debug("kobject: '%s' (%p): %s: filter function "
380 "caused the event to drop!\n",
381 kobject_name(kobj), kobj, __func__);
385 /* originating subsystem */
386 if (uevent_ops && uevent_ops->name)
387 subsystem = uevent_ops->name(kset, kobj);
389 subsystem = kobject_name(&kset->kobj);
391 pr_debug("kobject: '%s' (%p): %s: unset subsystem caused the "
392 "event to drop!\n", kobject_name(kobj), kobj,
397 /* environment buffer */
398 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
402 /* complete object path */
403 devpath = kobject_get_path(kobj, GFP_KERNEL);
410 retval = add_uevent_var(env, "ACTION=%s", action_string);
413 retval = add_uevent_var(env, "DEVPATH=%s", devpath);
416 retval = add_uevent_var(env, "SUBSYSTEM=%s", subsystem);
420 /* keys passed in from the caller */
422 for (i = 0; envp_ext[i]; i++) {
423 retval = add_uevent_var(env, "%s", envp_ext[i]);
429 /* let the kset specific function add its stuff */
430 if (uevent_ops && uevent_ops->uevent) {
431 retval = uevent_ops->uevent(kset, kobj, env);
433 pr_debug("kobject: '%s' (%p): %s: uevent() returned "
434 "%d\n", kobject_name(kobj), kobj,
443 * Mark "add" event so we can make sure we deliver "remove"
444 * event to userspace during automatic cleanup. If
445 * the object did send an "add" event, "remove" will
446 * automatically generated by the core, if not already done
449 kobj->state_add_uevent_sent = 1;
453 zap_modalias_env(env);
460 mutex_lock(&uevent_sock_mutex);
461 /* we will send an event, so request a new sequence number */
462 retval = add_uevent_var(env, "SEQNUM=%llu", (unsigned long long)++uevent_seqnum);
464 mutex_unlock(&uevent_sock_mutex);
468 #if defined(CONFIG_NET)
469 /* send netlink message */
470 list_for_each_entry(ue_sk, &uevent_sock_list, list) {
471 struct sock *uevent_sock = ue_sk->sk;
475 if (!netlink_has_listeners(uevent_sock, 1))
478 /* allocate message with the maximum possible size */
479 len = strlen(action_string) + strlen(devpath) + 2;
480 skb = alloc_skb(len + env->buflen, GFP_KERNEL);
485 scratch = skb_put(skb, len);
486 sprintf(scratch, "%s@%s", action_string, devpath);
488 /* copy keys to our continuous event payload buffer */
489 for (i = 0; i < env->envp_idx; i++) {
490 len = strlen(env->envp[i]) + 1;
491 scratch = skb_put(skb, len);
492 strcpy(scratch, env->envp[i]);
495 NETLINK_CB(skb).dst_group = 1;
496 retval = netlink_broadcast_filtered(uevent_sock, skb,
500 /* ENOBUFS should be handled in userspace */
501 if (retval == -ENOBUFS || retval == -ESRCH)
507 mutex_unlock(&uevent_sock_mutex);
509 #ifdef CONFIG_UEVENT_HELPER
510 /* call uevent_helper, usually only enabled during early boot */
511 if (uevent_helper[0] && !kobj_usermode_filter(kobj)) {
512 struct subprocess_info *info;
514 retval = add_uevent_var(env, "HOME=/");
517 retval = add_uevent_var(env,
518 "PATH=/sbin:/bin:/usr/sbin:/usr/bin");
521 retval = init_uevent_argv(env, subsystem);
526 info = call_usermodehelper_setup(env->argv[0], env->argv,
527 env->envp, GFP_KERNEL,
528 NULL, cleanup_uevent_env, env);
530 retval = call_usermodehelper_exec(info, UMH_NO_WAIT);
531 env = NULL; /* freed by cleanup_uevent_env */
541 EXPORT_SYMBOL_GPL(kobject_uevent_env);
544 * kobject_uevent - notify userspace by sending an uevent
546 * @kobj: struct kobject that the action is happening to
547 * @action: action that is happening
549 * Returns 0 if kobject_uevent() is completed with success or the
550 * corresponding error when it fails.
552 int kobject_uevent(struct kobject *kobj, enum kobject_action action)
554 return kobject_uevent_env(kobj, action, NULL);
556 EXPORT_SYMBOL_GPL(kobject_uevent);
559 * add_uevent_var - add key value string to the environment buffer
560 * @env: environment buffer structure
561 * @format: printf format for the key=value pair
563 * Returns 0 if environment variable was added successfully or -ENOMEM
564 * if no space was available.
566 int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
571 if (env->envp_idx >= ARRAY_SIZE(env->envp)) {
572 WARN(1, KERN_ERR "add_uevent_var: too many keys\n");
576 va_start(args, format);
577 len = vsnprintf(&env->buf[env->buflen],
578 sizeof(env->buf) - env->buflen,
582 if (len >= (sizeof(env->buf) - env->buflen)) {
583 WARN(1, KERN_ERR "add_uevent_var: buffer size too small\n");
587 env->envp[env->envp_idx++] = &env->buf[env->buflen];
588 env->buflen += len + 1;
591 EXPORT_SYMBOL_GPL(add_uevent_var);
593 #if defined(CONFIG_NET)
594 static int uevent_net_init(struct net *net)
596 struct uevent_sock *ue_sk;
597 struct netlink_kernel_cfg cfg = {
599 .flags = NL_CFG_F_NONROOT_RECV,
602 ue_sk = kzalloc(sizeof(*ue_sk), GFP_KERNEL);
606 ue_sk->sk = netlink_kernel_create(net, NETLINK_KOBJECT_UEVENT, &cfg);
609 "kobject_uevent: unable to create netlink socket!\n");
613 mutex_lock(&uevent_sock_mutex);
614 list_add_tail(&ue_sk->list, &uevent_sock_list);
615 mutex_unlock(&uevent_sock_mutex);
619 static void uevent_net_exit(struct net *net)
621 struct uevent_sock *ue_sk;
623 mutex_lock(&uevent_sock_mutex);
624 list_for_each_entry(ue_sk, &uevent_sock_list, list) {
625 if (sock_net(ue_sk->sk) == net)
628 mutex_unlock(&uevent_sock_mutex);
632 list_del(&ue_sk->list);
633 mutex_unlock(&uevent_sock_mutex);
635 netlink_kernel_release(ue_sk->sk);
639 static struct pernet_operations uevent_net_ops = {
640 .init = uevent_net_init,
641 .exit = uevent_net_exit,
644 static int __init kobject_uevent_init(void)
646 return register_pernet_subsys(&uevent_net_ops);
650 postcore_initcall(kobject_uevent_init);