Merge master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / lib / kobject_uevent.c
blob84272ed77f039c55de62be540ac19d23189cc06f
1 /*
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.
10 * Authors:
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>
23 #include <net/sock.h>
25 #define BUFFER_SIZE 2048 /* buffer for the variables */
26 #define NUM_ENVP 32 /* number of env pointers */
28 #if defined(CONFIG_HOTPLUG)
29 u64 uevent_seqnum;
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;
34 #endif
36 static char *action_to_string(enum kobject_action action)
38 switch (action) {
39 case KOBJ_ADD:
40 return "add";
41 case KOBJ_REMOVE:
42 return "remove";
43 case KOBJ_CHANGE:
44 return "change";
45 case KOBJ_MOUNT:
46 return "mount";
47 case KOBJ_UMOUNT:
48 return "umount";
49 case KOBJ_OFFLINE:
50 return "offline";
51 case KOBJ_ONLINE:
52 return "online";
53 case KOBJ_MOVE:
54 return "move";
55 default:
56 return NULL;
60 /**
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,
71 char *envp_ext[])
73 char **envp;
74 char *buffer;
75 char *scratch;
76 const char *action_string;
77 const char *devpath = NULL;
78 const char *subsystem;
79 struct kobject *top_kobj;
80 struct kset *kset;
81 struct kset_uevent_ops *uevent_ops;
82 u64 seq;
83 char *seq_buff;
84 int i = 0;
85 int retval = 0;
86 int j;
88 pr_debug("%s\n", __FUNCTION__);
90 action_string = action_to_string(action);
91 if (!action_string) {
92 pr_debug("kobject attempted to send uevent without action_string!\n");
93 return -EINVAL;
96 /* search the kset we belong to */
97 top_kobj = kobj;
98 if (!top_kobj->kset && top_kobj->parent) {
99 do {
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");
105 return -EINVAL;
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");
115 return 0;
118 /* environment index */
119 envp = kzalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL);
120 if (!envp)
121 return -ENOMEM;
123 /* environment values */
124 buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL);
125 if (!buffer) {
126 retval = -ENOMEM;
127 goto exit;
130 /* complete object path */
131 devpath = kobject_get_path(kobj, GFP_KERNEL);
132 if (!devpath) {
133 retval = -ENOENT;
134 goto exit;
137 /* originating subsystem */
138 if (uevent_ops && uevent_ops->name)
139 subsystem = uevent_ops->name(kset, kobj);
140 else
141 subsystem = kobject_name(&kset->kobj);
143 /* event environemnt for helper process only */
144 envp[i++] = "HOME=/";
145 envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
147 /* default keys */
148 scratch = buffer;
149 envp [i++] = scratch;
150 scratch += sprintf(scratch, "ACTION=%s", action_string) + 1;
151 envp [i++] = scratch;
152 scratch += sprintf (scratch, "DEVPATH=%s", devpath) + 1;
153 envp [i++] = scratch;
154 scratch += sprintf(scratch, "SUBSYSTEM=%s", subsystem) + 1;
155 for (j = 0; envp_ext && envp_ext[j]; j++)
156 envp[i++] = envp_ext[j];
157 /* just reserve the space, overwrite it after kset call has returned */
158 envp[i++] = seq_buff = scratch;
159 scratch += strlen("SEQNUM=18446744073709551616") + 1;
161 /* let the kset specific function add its stuff */
162 if (uevent_ops && uevent_ops->uevent) {
163 retval = uevent_ops->uevent(kset, kobj,
164 &envp[i], NUM_ENVP - i, scratch,
165 BUFFER_SIZE - (scratch - buffer));
166 if (retval) {
167 pr_debug ("%s - uevent() returned %d\n",
168 __FUNCTION__, retval);
169 goto exit;
173 /* we will send an event, request a new sequence number */
174 spin_lock(&sequence_lock);
175 seq = ++uevent_seqnum;
176 spin_unlock(&sequence_lock);
177 sprintf(seq_buff, "SEQNUM=%llu", (unsigned long long)seq);
179 #if defined(CONFIG_NET)
180 /* send netlink message */
181 if (uevent_sock) {
182 struct sk_buff *skb;
183 size_t len;
185 /* allocate message with the maximum possible size */
186 len = strlen(action_string) + strlen(devpath) + 2;
187 skb = alloc_skb(len + BUFFER_SIZE, GFP_KERNEL);
188 if (skb) {
189 /* add header */
190 scratch = skb_put(skb, len);
191 sprintf(scratch, "%s@%s", action_string, devpath);
193 /* copy keys to our continuous event payload buffer */
194 for (i = 2; envp[i]; i++) {
195 len = strlen(envp[i]) + 1;
196 scratch = skb_put(skb, len);
197 strcpy(scratch, envp[i]);
200 NETLINK_CB(skb).dst_group = 1;
201 netlink_broadcast(uevent_sock, skb, 0, 1, GFP_KERNEL);
204 #endif
206 /* call uevent_helper, usually only enabled during early boot */
207 if (uevent_helper[0]) {
208 char *argv [3];
210 argv [0] = uevent_helper;
211 argv [1] = (char *)subsystem;
212 argv [2] = NULL;
213 call_usermodehelper (argv[0], argv, envp, 0);
216 exit:
217 kfree(devpath);
218 kfree(buffer);
219 kfree(envp);
220 return retval;
223 EXPORT_SYMBOL_GPL(kobject_uevent_env);
226 * kobject_uevent - notify userspace by ending an uevent
228 * @action: action that is happening (usually KOBJ_ADD and KOBJ_REMOVE)
229 * @kobj: struct kobject that the action is happening to
231 * Returns 0 if kobject_uevent() is completed with success or the
232 * corresponding error when it fails.
234 int kobject_uevent(struct kobject *kobj, enum kobject_action action)
236 return kobject_uevent_env(kobj, action, NULL);
239 EXPORT_SYMBOL_GPL(kobject_uevent);
242 * add_uevent_var - helper for creating event variables
243 * @envp: Pointer to table of environment variables, as passed into
244 * uevent() method.
245 * @num_envp: Number of environment variable slots available, as
246 * passed into uevent() method.
247 * @cur_index: Pointer to current index into @envp. It should be
248 * initialized to 0 before the first call to add_uevent_var(),
249 * and will be incremented on success.
250 * @buffer: Pointer to buffer for environment variables, as passed
251 * into uevent() method.
252 * @buffer_size: Length of @buffer, as passed into uevent() method.
253 * @cur_len: Pointer to current length of space used in @buffer.
254 * Should be initialized to 0 before the first call to
255 * add_uevent_var(), and will be incremented on success.
256 * @format: Format for creating environment variable (of the form
257 * "XXX=%x") for snprintf().
259 * Returns 0 if environment variable was added successfully or -ENOMEM
260 * if no space was available.
262 int add_uevent_var(char **envp, int num_envp, int *cur_index,
263 char *buffer, int buffer_size, int *cur_len,
264 const char *format, ...)
266 va_list args;
269 * We check against num_envp - 1 to make sure there is at
270 * least one slot left after we return, since kobject_uevent()
271 * needs to set the last slot to NULL.
273 if (*cur_index >= num_envp - 1)
274 return -ENOMEM;
276 envp[*cur_index] = buffer + *cur_len;
278 va_start(args, format);
279 *cur_len += vsnprintf(envp[*cur_index],
280 max(buffer_size - *cur_len, 0),
281 format, args) + 1;
282 va_end(args);
284 if (*cur_len > buffer_size)
285 return -ENOMEM;
287 (*cur_index)++;
288 return 0;
290 EXPORT_SYMBOL_GPL(add_uevent_var);
292 #if defined(CONFIG_NET)
293 static int __init kobject_uevent_init(void)
295 uevent_sock = netlink_kernel_create(NETLINK_KOBJECT_UEVENT, 1, NULL,
296 THIS_MODULE);
298 if (!uevent_sock) {
299 printk(KERN_ERR
300 "kobject_uevent: unable to create netlink socket!\n");
301 return -ENODEV;
304 return 0;
307 postcore_initcall(kobject_uevent_init);
308 #endif
310 #endif /* CONFIG_HOTPLUG */