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 2048 /* buffer for the variables */
26 #define NUM_ENVP 32 /* number of env pointers */
28 #if defined(CONFIG_HOTPLUG)
30 char uevent_helper[UEVENT_HELPER_PATH_LEN] = "/sbin/hotplug";
31 static DEFINE_SPINLOCK(sequence_lock);
32 #if defined(CONFIG_NET)
33 static struct sock *uevent_sock;
36 static char *action_to_string(enum kobject_action action)
61 * kobject_uevent_env - send an uevent with environmental data
63 * @action: action that is happening (usually KOBJ_MOVE)
64 * @kobj: struct kobject that the action is happening to
65 * @envp_ext: pointer to environmental data
67 * Returns 0 if kobject_uevent() is completed with success or the
68 * corresponding error when it fails.
70 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
76 const char *action_string;
77 const char *devpath = NULL;
78 const char *subsystem;
79 struct kobject *top_kobj;
81 struct kset_uevent_ops *uevent_ops;
88 pr_debug("%s\n", __FUNCTION__);
90 action_string = action_to_string(action);
92 pr_debug("kobject attempted to send uevent without action_string!\n");
96 /* search the kset we belong to */
98 if (!top_kobj->kset && top_kobj->parent) {
100 top_kobj = top_kobj->parent;
101 } while (!top_kobj->kset && top_kobj->parent);
103 if (!top_kobj->kset) {
104 pr_debug("kobject attempted to send uevent without kset!\n");
108 kset = top_kobj->kset;
109 uevent_ops = kset->uevent_ops;
111 /* skip the event, if the filter returns zero. */
112 if (uevent_ops && uevent_ops->filter)
113 if (!uevent_ops->filter(kset, kobj)) {
114 pr_debug("kobject filter function caused the event to drop!\n");
118 /* originating subsystem */
119 if (uevent_ops && uevent_ops->name)
120 subsystem = uevent_ops->name(kset, kobj);
122 subsystem = kobject_name(&kset->kobj);
124 pr_debug("unset subsytem caused the event to drop!\n");
128 /* environment index */
129 envp = kzalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL);
133 /* environment values */
134 buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL);
140 /* complete object path */
141 devpath = kobject_get_path(kobj, GFP_KERNEL);
147 /* event environemnt for helper process only */
148 envp[i++] = "HOME=/";
149 envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
153 envp [i++] = scratch;
154 scratch += sprintf(scratch, "ACTION=%s", action_string) + 1;
155 envp [i++] = scratch;
156 scratch += sprintf (scratch, "DEVPATH=%s", devpath) + 1;
157 envp [i++] = scratch;
158 scratch += sprintf(scratch, "SUBSYSTEM=%s", subsystem) + 1;
159 for (j = 0; envp_ext && envp_ext[j]; j++)
160 envp[i++] = envp_ext[j];
161 /* just reserve the space, overwrite it after kset call has returned */
162 envp[i++] = seq_buff = scratch;
163 scratch += strlen("SEQNUM=18446744073709551616") + 1;
165 /* let the kset specific function add its stuff */
166 if (uevent_ops && uevent_ops->uevent) {
167 retval = uevent_ops->uevent(kset, kobj,
168 &envp[i], NUM_ENVP - i, scratch,
169 BUFFER_SIZE - (scratch - buffer));
171 pr_debug ("%s - uevent() returned %d\n",
172 __FUNCTION__, retval);
177 /* we will send an event, request a new sequence number */
178 spin_lock(&sequence_lock);
179 seq = ++uevent_seqnum;
180 spin_unlock(&sequence_lock);
181 sprintf(seq_buff, "SEQNUM=%llu", (unsigned long long)seq);
183 #if defined(CONFIG_NET)
184 /* send netlink message */
189 /* allocate message with the maximum possible size */
190 len = strlen(action_string) + strlen(devpath) + 2;
191 skb = alloc_skb(len + BUFFER_SIZE, GFP_KERNEL);
194 scratch = skb_put(skb, len);
195 sprintf(scratch, "%s@%s", action_string, devpath);
197 /* copy keys to our continuous event payload buffer */
198 for (i = 2; envp[i]; i++) {
199 len = strlen(envp[i]) + 1;
200 scratch = skb_put(skb, len);
201 strcpy(scratch, envp[i]);
204 NETLINK_CB(skb).dst_group = 1;
205 netlink_broadcast(uevent_sock, skb, 0, 1, GFP_KERNEL);
210 /* call uevent_helper, usually only enabled during early boot */
211 if (uevent_helper[0]) {
214 argv [0] = uevent_helper;
215 argv [1] = (char *)subsystem;
217 call_usermodehelper (argv[0], argv, envp, 0);
227 EXPORT_SYMBOL_GPL(kobject_uevent_env);
230 * kobject_uevent - notify userspace by ending an uevent
232 * @action: action that is happening (usually KOBJ_ADD and KOBJ_REMOVE)
233 * @kobj: struct kobject that the action is happening to
235 * Returns 0 if kobject_uevent() is completed with success or the
236 * corresponding error when it fails.
238 int kobject_uevent(struct kobject *kobj, enum kobject_action action)
240 return kobject_uevent_env(kobj, action, NULL);
243 EXPORT_SYMBOL_GPL(kobject_uevent);
246 * add_uevent_var - helper for creating event variables
247 * @envp: Pointer to table of environment variables, as passed into
249 * @num_envp: Number of environment variable slots available, as
250 * passed into uevent() method.
251 * @cur_index: Pointer to current index into @envp. It should be
252 * initialized to 0 before the first call to add_uevent_var(),
253 * and will be incremented on success.
254 * @buffer: Pointer to buffer for environment variables, as passed
255 * into uevent() method.
256 * @buffer_size: Length of @buffer, as passed into uevent() method.
257 * @cur_len: Pointer to current length of space used in @buffer.
258 * Should be initialized to 0 before the first call to
259 * add_uevent_var(), and will be incremented on success.
260 * @format: Format for creating environment variable (of the form
261 * "XXX=%x") for snprintf().
263 * Returns 0 if environment variable was added successfully or -ENOMEM
264 * if no space was available.
266 int add_uevent_var(char **envp, int num_envp, int *cur_index,
267 char *buffer, int buffer_size, int *cur_len,
268 const char *format, ...)
273 * We check against num_envp - 1 to make sure there is at
274 * least one slot left after we return, since kobject_uevent()
275 * needs to set the last slot to NULL.
277 if (*cur_index >= num_envp - 1)
280 envp[*cur_index] = buffer + *cur_len;
282 va_start(args, format);
283 *cur_len += vsnprintf(envp[*cur_index],
284 max(buffer_size - *cur_len, 0),
288 if (*cur_len > buffer_size)
294 EXPORT_SYMBOL_GPL(add_uevent_var);
296 #if defined(CONFIG_NET)
297 static int __init kobject_uevent_init(void)
299 uevent_sock = netlink_kernel_create(NETLINK_KOBJECT_UEVENT, 1, NULL,
304 "kobject_uevent: unable to create netlink socket!\n");
311 postcore_initcall(kobject_uevent_init);
314 #endif /* CONFIG_HOTPLUG */