Blackfin arch: fix a few random warnings
[wrt350n-kernel.git] / lib / kobject_uevent.c
blob12e311dc664cc8d58aa29264050e2f4a8f234e2c
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_OFFLINE:
46 return "offline";
47 case KOBJ_ONLINE:
48 return "online";
49 case KOBJ_MOVE:
50 return "move";
51 default:
52 return NULL;
56 /**
57 * kobject_uevent_env - send an uevent with environmental data
59 * @action: action that is happening (usually KOBJ_MOVE)
60 * @kobj: struct kobject that the action is happening to
61 * @envp_ext: pointer to environmental data
63 * Returns 0 if kobject_uevent() is completed with success or the
64 * corresponding error when it fails.
66 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
67 char *envp_ext[])
69 char **envp;
70 char *buffer;
71 char *scratch;
72 const char *action_string;
73 const char *devpath = NULL;
74 const char *subsystem;
75 struct kobject *top_kobj;
76 struct kset *kset;
77 struct kset_uevent_ops *uevent_ops;
78 u64 seq;
79 char *seq_buff;
80 int i = 0;
81 int retval = 0;
82 int j;
84 pr_debug("%s\n", __FUNCTION__);
86 action_string = action_to_string(action);
87 if (!action_string) {
88 pr_debug("kobject attempted to send uevent without action_string!\n");
89 return -EINVAL;
92 /* search the kset we belong to */
93 top_kobj = kobj;
94 while (!top_kobj->kset && top_kobj->parent) {
95 top_kobj = top_kobj->parent;
97 if (!top_kobj->kset) {
98 pr_debug("kobject attempted to send uevent without kset!\n");
99 return -EINVAL;
102 kset = top_kobj->kset;
103 uevent_ops = kset->uevent_ops;
105 /* skip the event, if the filter returns zero. */
106 if (uevent_ops && uevent_ops->filter)
107 if (!uevent_ops->filter(kset, kobj)) {
108 pr_debug("kobject filter function caused the event to drop!\n");
109 return 0;
112 /* originating subsystem */
113 if (uevent_ops && uevent_ops->name)
114 subsystem = uevent_ops->name(kset, kobj);
115 else
116 subsystem = kobject_name(&kset->kobj);
117 if (!subsystem) {
118 pr_debug("unset subsytem caused the event to drop!\n");
119 return 0;
122 /* environment index */
123 envp = kzalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL);
124 if (!envp)
125 return -ENOMEM;
127 /* environment values */
128 buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL);
129 if (!buffer) {
130 retval = -ENOMEM;
131 goto exit;
134 /* complete object path */
135 devpath = kobject_get_path(kobj, GFP_KERNEL);
136 if (!devpath) {
137 retval = -ENOENT;
138 goto exit;
141 /* event environemnt for helper process only */
142 envp[i++] = "HOME=/";
143 envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
145 /* default keys */
146 scratch = buffer;
147 envp [i++] = scratch;
148 scratch += sprintf(scratch, "ACTION=%s", action_string) + 1;
149 envp [i++] = scratch;
150 scratch += sprintf (scratch, "DEVPATH=%s", devpath) + 1;
151 envp [i++] = scratch;
152 scratch += sprintf(scratch, "SUBSYSTEM=%s", subsystem) + 1;
153 for (j = 0; envp_ext && envp_ext[j]; j++)
154 envp[i++] = envp_ext[j];
155 /* just reserve the space, overwrite it after kset call has returned */
156 envp[i++] = seq_buff = scratch;
157 scratch += strlen("SEQNUM=18446744073709551616") + 1;
159 /* let the kset specific function add its stuff */
160 if (uevent_ops && uevent_ops->uevent) {
161 retval = uevent_ops->uevent(kset, kobj,
162 &envp[i], NUM_ENVP - i, scratch,
163 BUFFER_SIZE - (scratch - buffer));
164 if (retval) {
165 pr_debug ("%s - uevent() returned %d\n",
166 __FUNCTION__, retval);
167 goto exit;
171 /* we will send an event, request a new sequence number */
172 spin_lock(&sequence_lock);
173 seq = ++uevent_seqnum;
174 spin_unlock(&sequence_lock);
175 sprintf(seq_buff, "SEQNUM=%llu", (unsigned long long)seq);
177 #if defined(CONFIG_NET)
178 /* send netlink message */
179 if (uevent_sock) {
180 struct sk_buff *skb;
181 size_t len;
183 /* allocate message with the maximum possible size */
184 len = strlen(action_string) + strlen(devpath) + 2;
185 skb = alloc_skb(len + BUFFER_SIZE, GFP_KERNEL);
186 if (skb) {
187 /* add header */
188 scratch = skb_put(skb, len);
189 sprintf(scratch, "%s@%s", action_string, devpath);
191 /* copy keys to our continuous event payload buffer */
192 for (i = 2; envp[i]; i++) {
193 len = strlen(envp[i]) + 1;
194 scratch = skb_put(skb, len);
195 strcpy(scratch, envp[i]);
198 NETLINK_CB(skb).dst_group = 1;
199 netlink_broadcast(uevent_sock, skb, 0, 1, GFP_KERNEL);
202 #endif
204 /* call uevent_helper, usually only enabled during early boot */
205 if (uevent_helper[0]) {
206 char *argv [3];
208 argv [0] = uevent_helper;
209 argv [1] = (char *)subsystem;
210 argv [2] = NULL;
211 call_usermodehelper (argv[0], argv, envp, 0);
214 exit:
215 kfree(devpath);
216 kfree(buffer);
217 kfree(envp);
218 return retval;
221 EXPORT_SYMBOL_GPL(kobject_uevent_env);
224 * kobject_uevent - notify userspace by ending an uevent
226 * @action: action that is happening (usually KOBJ_ADD and KOBJ_REMOVE)
227 * @kobj: struct kobject that the action is happening to
229 * Returns 0 if kobject_uevent() is completed with success or the
230 * corresponding error when it fails.
232 int kobject_uevent(struct kobject *kobj, enum kobject_action action)
234 return kobject_uevent_env(kobj, action, NULL);
237 EXPORT_SYMBOL_GPL(kobject_uevent);
240 * add_uevent_var - helper for creating event variables
241 * @envp: Pointer to table of environment variables, as passed into
242 * uevent() method.
243 * @num_envp: Number of environment variable slots available, as
244 * passed into uevent() method.
245 * @cur_index: Pointer to current index into @envp. It should be
246 * initialized to 0 before the first call to add_uevent_var(),
247 * and will be incremented on success.
248 * @buffer: Pointer to buffer for environment variables, as passed
249 * into uevent() method.
250 * @buffer_size: Length of @buffer, as passed into uevent() method.
251 * @cur_len: Pointer to current length of space used in @buffer.
252 * Should be initialized to 0 before the first call to
253 * add_uevent_var(), and will be incremented on success.
254 * @format: Format for creating environment variable (of the form
255 * "XXX=%x") for snprintf().
257 * Returns 0 if environment variable was added successfully or -ENOMEM
258 * if no space was available.
260 int add_uevent_var(char **envp, int num_envp, int *cur_index,
261 char *buffer, int buffer_size, int *cur_len,
262 const char *format, ...)
264 va_list args;
267 * We check against num_envp - 1 to make sure there is at
268 * least one slot left after we return, since kobject_uevent()
269 * needs to set the last slot to NULL.
271 if (*cur_index >= num_envp - 1)
272 return -ENOMEM;
274 envp[*cur_index] = buffer + *cur_len;
276 va_start(args, format);
277 *cur_len += vsnprintf(envp[*cur_index],
278 max(buffer_size - *cur_len, 0),
279 format, args) + 1;
280 va_end(args);
282 if (*cur_len > buffer_size)
283 return -ENOMEM;
285 (*cur_index)++;
286 return 0;
288 EXPORT_SYMBOL_GPL(add_uevent_var);
290 #if defined(CONFIG_NET)
291 static int __init kobject_uevent_init(void)
293 uevent_sock = netlink_kernel_create(NETLINK_KOBJECT_UEVENT, 1, NULL,
294 NULL, THIS_MODULE);
296 if (!uevent_sock) {
297 printk(KERN_ERR
298 "kobject_uevent: unable to create netlink socket!\n");
299 return -ENODEV;
302 return 0;
305 postcore_initcall(kobject_uevent_init);
306 #endif
308 #endif /* CONFIG_HOTPLUG */