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>
22 #include <linux/user_namespace.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 static int kobj_bcast_filter(struct sock
*dsk
, struct sk_buff
*skb
, void *data
)
89 struct kobject
*kobj
= data
;
90 const struct kobj_ns_type_operations
*ops
;
92 ops
= kobj_ns_ops(kobj
);
94 const void *sock_ns
, *ns
;
95 ns
= kobj
->ktype
->namespace(kobj
);
96 sock_ns
= ops
->netlink_ns(dsk
);
104 static int kobj_usermode_filter(struct kobject
*kobj
)
106 const struct kobj_ns_type_operations
*ops
;
108 ops
= kobj_ns_ops(kobj
);
110 const void *init_ns
, *ns
;
111 ns
= kobj
->ktype
->namespace(kobj
);
112 init_ns
= ops
->initial_ns();
113 return ns
!= init_ns
;
120 * kobject_uevent_env - send an uevent with environmental data
122 * @action: action that is happening
123 * @kobj: struct kobject that the action is happening to
124 * @envp_ext: pointer to environmental data
126 * Returns 0 if kobject_uevent_env() is completed with success or the
127 * corresponding error when it fails.
129 int kobject_uevent_env(struct kobject
*kobj
, enum kobject_action action
,
132 struct kobj_uevent_env
*env
;
133 const char *action_string
= kobject_actions
[action
];
134 const char *devpath
= NULL
;
135 const char *subsystem
;
136 struct kobject
*top_kobj
;
138 const struct kset_uevent_ops
*uevent_ops
;
143 struct uevent_sock
*ue_sk
;
146 pr_debug("kobject: '%s' (%p): %s\n",
147 kobject_name(kobj
), kobj
, __func__
);
149 /* search the kset we belong to */
151 while (!top_kobj
->kset
&& top_kobj
->parent
)
152 top_kobj
= top_kobj
->parent
;
154 if (!top_kobj
->kset
) {
155 pr_debug("kobject: '%s' (%p): %s: attempted to send uevent "
156 "without kset!\n", kobject_name(kobj
), kobj
,
161 kset
= top_kobj
->kset
;
162 uevent_ops
= kset
->uevent_ops
;
164 /* skip the event, if uevent_suppress is set*/
165 if (kobj
->uevent_suppress
) {
166 pr_debug("kobject: '%s' (%p): %s: uevent_suppress "
167 "caused the event to drop!\n",
168 kobject_name(kobj
), kobj
, __func__
);
171 /* skip the event, if the filter returns zero. */
172 if (uevent_ops
&& uevent_ops
->filter
)
173 if (!uevent_ops
->filter(kset
, kobj
)) {
174 pr_debug("kobject: '%s' (%p): %s: filter function "
175 "caused the event to drop!\n",
176 kobject_name(kobj
), kobj
, __func__
);
180 /* originating subsystem */
181 if (uevent_ops
&& uevent_ops
->name
)
182 subsystem
= uevent_ops
->name(kset
, kobj
);
184 subsystem
= kobject_name(&kset
->kobj
);
186 pr_debug("kobject: '%s' (%p): %s: unset subsystem caused the "
187 "event to drop!\n", kobject_name(kobj
), kobj
,
192 /* environment buffer */
193 env
= kzalloc(sizeof(struct kobj_uevent_env
), GFP_KERNEL
);
197 /* complete object path */
198 devpath
= kobject_get_path(kobj
, GFP_KERNEL
);
205 retval
= add_uevent_var(env
, "ACTION=%s", action_string
);
208 retval
= add_uevent_var(env
, "DEVPATH=%s", devpath
);
211 retval
= add_uevent_var(env
, "SUBSYSTEM=%s", subsystem
);
215 /* keys passed in from the caller */
217 for (i
= 0; envp_ext
[i
]; i
++) {
218 retval
= add_uevent_var(env
, "%s", envp_ext
[i
]);
224 /* let the kset specific function add its stuff */
225 if (uevent_ops
&& uevent_ops
->uevent
) {
226 retval
= uevent_ops
->uevent(kset
, kobj
, env
);
228 pr_debug("kobject: '%s' (%p): %s: uevent() returned "
229 "%d\n", kobject_name(kobj
), kobj
,
236 * Mark "add" and "remove" events in the object to ensure proper
237 * events to userspace during automatic cleanup. If the object did
238 * send an "add" event, "remove" will automatically generated by
239 * the core, if not already done by the caller.
241 if (action
== KOBJ_ADD
)
242 kobj
->state_add_uevent_sent
= 1;
243 else if (action
== KOBJ_REMOVE
)
244 kobj
->state_remove_uevent_sent
= 1;
246 /* we will send an event, so request a new sequence number */
247 spin_lock(&sequence_lock
);
248 seq
= ++uevent_seqnum
;
249 spin_unlock(&sequence_lock
);
250 retval
= add_uevent_var(env
, "SEQNUM=%llu", (unsigned long long)seq
);
254 #if defined(CONFIG_NET)
255 /* send netlink message */
256 mutex_lock(&uevent_sock_mutex
);
257 list_for_each_entry(ue_sk
, &uevent_sock_list
, list
) {
258 struct sock
*uevent_sock
= ue_sk
->sk
;
262 /* allocate message with the maximum possible size */
263 len
= strlen(action_string
) + strlen(devpath
) + 2;
264 skb
= alloc_skb(len
+ env
->buflen
, GFP_KERNEL
);
269 scratch
= skb_put(skb
, len
);
270 sprintf(scratch
, "%s@%s", action_string
, devpath
);
272 /* copy keys to our continuous event payload buffer */
273 for (i
= 0; i
< env
->envp_idx
; i
++) {
274 len
= strlen(env
->envp
[i
]) + 1;
275 scratch
= skb_put(skb
, len
);
276 strcpy(scratch
, env
->envp
[i
]);
279 NETLINK_CB(skb
).dst_group
= 1;
280 retval
= netlink_broadcast_filtered(uevent_sock
, skb
,
284 /* ENOBUFS should be handled in userspace */
285 if (retval
== -ENOBUFS
)
290 mutex_unlock(&uevent_sock_mutex
);
293 /* call uevent_helper, usually only enabled during early boot */
294 if (uevent_helper
[0] && !kobj_usermode_filter(kobj
)) {
297 argv
[0] = uevent_helper
;
298 argv
[1] = (char *)subsystem
;
300 retval
= add_uevent_var(env
, "HOME=/");
303 retval
= add_uevent_var(env
,
304 "PATH=/sbin:/bin:/usr/sbin:/usr/bin");
308 retval
= call_usermodehelper(argv
[0], argv
,
309 env
->envp
, UMH_WAIT_EXEC
);
317 EXPORT_SYMBOL_GPL(kobject_uevent_env
);
320 * kobject_uevent - notify userspace by sending an uevent
322 * @action: action that is happening
323 * @kobj: struct kobject that the action is happening to
325 * Returns 0 if kobject_uevent() is completed with success or the
326 * corresponding error when it fails.
328 int kobject_uevent(struct kobject
*kobj
, enum kobject_action action
)
330 return kobject_uevent_env(kobj
, action
, NULL
);
332 EXPORT_SYMBOL_GPL(kobject_uevent
);
335 * add_uevent_var - add key value string to the environment buffer
336 * @env: environment buffer structure
337 * @format: printf format for the key=value pair
339 * Returns 0 if environment variable was added successfully or -ENOMEM
340 * if no space was available.
342 int add_uevent_var(struct kobj_uevent_env
*env
, const char *format
, ...)
347 if (env
->envp_idx
>= ARRAY_SIZE(env
->envp
)) {
348 WARN(1, KERN_ERR
"add_uevent_var: too many keys\n");
352 va_start(args
, format
);
353 len
= vsnprintf(&env
->buf
[env
->buflen
],
354 sizeof(env
->buf
) - env
->buflen
,
358 if (len
>= (sizeof(env
->buf
) - env
->buflen
)) {
359 WARN(1, KERN_ERR
"add_uevent_var: buffer size too small\n");
363 env
->envp
[env
->envp_idx
++] = &env
->buf
[env
->buflen
];
364 env
->buflen
+= len
+ 1;
367 EXPORT_SYMBOL_GPL(add_uevent_var
);
369 #if defined(CONFIG_NET)
370 static int uevent_net_init(struct net
*net
)
372 struct uevent_sock
*ue_sk
;
374 ue_sk
= kzalloc(sizeof(*ue_sk
), GFP_KERNEL
);
378 ue_sk
->sk
= netlink_kernel_create(net
, NETLINK_KOBJECT_UEVENT
,
379 1, NULL
, NULL
, THIS_MODULE
);
382 "kobject_uevent: unable to create netlink socket!\n");
386 mutex_lock(&uevent_sock_mutex
);
387 list_add_tail(&ue_sk
->list
, &uevent_sock_list
);
388 mutex_unlock(&uevent_sock_mutex
);
392 static void uevent_net_exit(struct net
*net
)
394 struct uevent_sock
*ue_sk
;
396 mutex_lock(&uevent_sock_mutex
);
397 list_for_each_entry(ue_sk
, &uevent_sock_list
, list
) {
398 if (sock_net(ue_sk
->sk
) == net
)
401 mutex_unlock(&uevent_sock_mutex
);
405 list_del(&ue_sk
->list
);
406 mutex_unlock(&uevent_sock_mutex
);
408 netlink_kernel_release(ue_sk
->sk
);
412 static struct pernet_operations uevent_net_ops
= {
413 .init
= uevent_net_init
,
414 .exit
= uevent_net_exit
,
417 static int __init
kobject_uevent_init(void)
419 netlink_set_nonroot(NETLINK_KOBJECT_UEVENT
, NL_NONROOT_RECV
);
420 return register_pernet_subsys(&uevent_net_ops
);
424 postcore_initcall(kobject_uevent_init
);