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/socket.h>
19 #include <linux/skbuff.h>
20 #include <linux/netlink.h>
21 #include <linux/string.h>
22 #include <linux/kobject.h>
25 #define BUFFER_SIZE 1024 /* buffer for the variables */
26 #define NUM_ENVP 32 /* number of env pointers */
28 #if defined(CONFIG_HOTPLUG)
29 char uevent_helper
[UEVENT_HELPER_PATH_LEN
] = "/sbin/hotplug";
31 static DEFINE_SPINLOCK(sequence_lock
);
32 static struct sock
*uevent_sock
;
34 static char *action_to_string(enum kobject_action action
)
53 * kobject_uevent - notify userspace by ending an uevent
55 * @action: action that is happening (usually KOBJ_ADD and KOBJ_REMOVE)
56 * @kobj: struct kobject that the action is happening to
58 void kobject_uevent(struct kobject
*kobj
, enum kobject_action action
)
63 const char *action_string
;
64 const char *devpath
= NULL
;
65 const char *subsystem
;
66 struct kobject
*top_kobj
;
68 struct kset_uevent_ops
*uevent_ops
;
74 pr_debug("%s\n", __FUNCTION__
);
76 action_string
= action_to_string(action
);
80 /* search the kset we belong to */
82 if (!top_kobj
->kset
&& top_kobj
->parent
) {
84 top_kobj
= top_kobj
->parent
;
85 } while (!top_kobj
->kset
&& top_kobj
->parent
);
90 kset
= top_kobj
->kset
;
91 uevent_ops
= kset
->uevent_ops
;
93 /* skip the event, if the filter returns zero. */
94 if (uevent_ops
&& uevent_ops
->filter
)
95 if (!uevent_ops
->filter(kset
, kobj
))
98 /* environment index */
99 envp
= kzalloc(NUM_ENVP
* sizeof (char *), GFP_KERNEL
);
103 /* environment values */
104 buffer
= kmalloc(BUFFER_SIZE
, GFP_KERNEL
);
108 /* complete object path */
109 devpath
= kobject_get_path(kobj
, GFP_KERNEL
);
113 /* originating subsystem */
114 if (uevent_ops
&& uevent_ops
->name
)
115 subsystem
= uevent_ops
->name(kset
, kobj
);
117 subsystem
= kobject_name(&kset
->kobj
);
119 /* event environemnt for helper process only */
120 envp
[i
++] = "HOME=/";
121 envp
[i
++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
125 envp
[i
++] = scratch
;
126 scratch
+= sprintf(scratch
, "ACTION=%s", action_string
) + 1;
127 envp
[i
++] = scratch
;
128 scratch
+= sprintf (scratch
, "DEVPATH=%s", devpath
) + 1;
129 envp
[i
++] = scratch
;
130 scratch
+= sprintf(scratch
, "SUBSYSTEM=%s", subsystem
) + 1;
132 /* just reserve the space, overwrite it after kset call has returned */
133 envp
[i
++] = seq_buff
= scratch
;
134 scratch
+= strlen("SEQNUM=18446744073709551616") + 1;
136 /* let the kset specific function add its stuff */
137 if (uevent_ops
&& uevent_ops
->uevent
) {
138 retval
= uevent_ops
->uevent(kset
, kobj
,
139 &envp
[i
], NUM_ENVP
- i
, scratch
,
140 BUFFER_SIZE
- (scratch
- buffer
));
142 pr_debug ("%s - uevent() returned %d\n",
143 __FUNCTION__
, retval
);
148 /* we will send an event, request a new sequence number */
149 spin_lock(&sequence_lock
);
150 seq
= ++uevent_seqnum
;
151 spin_unlock(&sequence_lock
);
152 sprintf(seq_buff
, "SEQNUM=%llu", (unsigned long long)seq
);
154 /* send netlink message */
159 /* allocate message with the maximum possible size */
160 len
= strlen(action_string
) + strlen(devpath
) + 2;
161 skb
= alloc_skb(len
+ BUFFER_SIZE
, GFP_KERNEL
);
164 scratch
= skb_put(skb
, len
);
165 sprintf(scratch
, "%s@%s", action_string
, devpath
);
167 /* copy keys to our continuous event payload buffer */
168 for (i
= 2; envp
[i
]; i
++) {
169 len
= strlen(envp
[i
]) + 1;
170 scratch
= skb_put(skb
, len
);
171 strcpy(scratch
, envp
[i
]);
174 NETLINK_CB(skb
).dst_group
= 1;
175 netlink_broadcast(uevent_sock
, skb
, 0, 1, GFP_KERNEL
);
179 /* call uevent_helper, usually only enabled during early boot */
180 if (uevent_helper
[0]) {
183 argv
[0] = uevent_helper
;
184 argv
[1] = (char *)subsystem
;
186 call_usermodehelper (argv
[0], argv
, envp
, 0);
195 EXPORT_SYMBOL_GPL(kobject_uevent
);
198 * add_uevent_var - helper for creating event variables
199 * @envp: Pointer to table of environment variables, as passed into
201 * @num_envp: Number of environment variable slots available, as
202 * passed into uevent() method.
203 * @cur_index: Pointer to current index into @envp. It should be
204 * initialized to 0 before the first call to add_uevent_var(),
205 * and will be incremented on success.
206 * @buffer: Pointer to buffer for environment variables, as passed
207 * into uevent() method.
208 * @buffer_size: Length of @buffer, as passed into uevent() method.
209 * @cur_len: Pointer to current length of space used in @buffer.
210 * Should be initialized to 0 before the first call to
211 * add_uevent_var(), and will be incremented on success.
212 * @format: Format for creating environment variable (of the form
213 * "XXX=%x") for snprintf().
215 * Returns 0 if environment variable was added successfully or -ENOMEM
216 * if no space was available.
218 int add_uevent_var(char **envp
, int num_envp
, int *cur_index
,
219 char *buffer
, int buffer_size
, int *cur_len
,
220 const char *format
, ...)
225 * We check against num_envp - 1 to make sure there is at
226 * least one slot left after we return, since kobject_uevent()
227 * needs to set the last slot to NULL.
229 if (*cur_index
>= num_envp
- 1)
232 envp
[*cur_index
] = buffer
+ *cur_len
;
234 va_start(args
, format
);
235 *cur_len
+= vsnprintf(envp
[*cur_index
],
236 max(buffer_size
- *cur_len
, 0),
240 if (*cur_len
> buffer_size
)
246 EXPORT_SYMBOL_GPL(add_uevent_var
);
248 static int __init
kobject_uevent_init(void)
250 uevent_sock
= netlink_kernel_create(NETLINK_KOBJECT_UEVENT
, 1, NULL
,
255 "kobject_uevent: unable to create netlink socket!\n");
262 postcore_initcall(kobject_uevent_init
);
264 #endif /* CONFIG_HOTPLUG */
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