projects/linux·blob v2.6.21 · refs

310 lines · 7.8 KiB

1/*
2 * kernel userspace event delivery
3 *
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.
7 *
8 * Licensed under the GNU GPL v2.
9 *
10 * Authors:
11 * Robert Love <[email protected]>
12 * Kay Sievers <[email protected]>
13 * Arjan van de Ven <[email protected]>
14 * Greg Kroah-Hartman <[email protected]>
15 */
16
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>
24
25#define BUFFER_SIZE 2048 /* buffer for the variables */
26#define NUM_ENVP 32 /* number of env pointers */
27
28#if defined(CONFIG_HOTPLUG)
29u64 uevent_seqnum;
30char uevent_helper[UEVENT_HELPER_PATH_LEN] = "/sbin/hotplug";
31static DEFINE_SPINLOCK(sequence_lock);
32#if defined(CONFIG_NET)
33static struct sock *uevent_sock;
34#endif
35
36static char *action_to_string(enum kobject_action action)
37{
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;
57 }
58}
59
60/**
61 * kobject_uevent_env - send an uevent with environmental data
62 *
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
66 *
67 * Returns 0 if kobject_uevent() is completed with success or the
68 * corresponding error when it fails.
69 */
70int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
71 char *envp_ext[])
72{
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;
87
88 pr_debug("%s\n", __FUNCTION__);
89
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;
94 }
95
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);
102 }
103 if (!top_kobj->kset) {
104 pr_debug("kobject attempted to send uevent without kset!\n");
105 return -EINVAL;
106 }
107
108 kset = top_kobj->kset;
109 uevent_ops = kset->uevent_ops;
110
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;
116 }
117
118 /* environment index */
119 envp = kzalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL);
120 if (!envp)
121 return -ENOMEM;
122
123 /* environment values */
124 buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL);
125 if (!buffer) {
126 retval = -ENOMEM;
127 goto exit;
128 }
129
130 /* complete object path */
131 devpath = kobject_get_path(kobj, GFP_KERNEL);
132 if (!devpath) {
133 retval = -ENOENT;
134 goto exit;
135 }
136
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);
142
143 /* event environemnt for helper process only */
144 envp[i++] = "HOME=/";
145 envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
146
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;
160
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;
170 }
171 }
172
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);
178
179#if defined(CONFIG_NET)
180 /* send netlink message */
181 if (uevent_sock) {
182 struct sk_buff *skb;
183 size_t len;
184
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);
192
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]);
198 }
199
200 NETLINK_CB(skb).dst_group = 1;
201 netlink_broadcast(uevent_sock, skb, 0, 1, GFP_KERNEL);
202 }
203 }
204#endif
205
206 /* call uevent_helper, usually only enabled during early boot */
207 if (uevent_helper[0]) {
208 char *argv [3];
209
210 argv [0] = uevent_helper;
211 argv [1] = (char *)subsystem;
212 argv [2] = NULL;
213 call_usermodehelper (argv[0], argv, envp, 0);
214 }
215
216exit:
217 kfree(devpath);
218 kfree(buffer);
219 kfree(envp);
220 return retval;
221}
222
223EXPORT_SYMBOL_GPL(kobject_uevent_env);
224
225/**
226 * kobject_uevent - notify userspace by ending an uevent
227 *
228 * @action: action that is happening (usually KOBJ_ADD and KOBJ_REMOVE)
229 * @kobj: struct kobject that the action is happening to
230 *
231 * Returns 0 if kobject_uevent() is completed with success or the
232 * corresponding error when it fails.
233 */
234int kobject_uevent(struct kobject *kobj, enum kobject_action action)
235{
236 return kobject_uevent_env(kobj, action, NULL);
237}
238
239EXPORT_SYMBOL_GPL(kobject_uevent);
240
241/**
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().
258 *
259 * Returns 0 if environment variable was added successfully or -ENOMEM
260 * if no space was available.
261 */
262int add_uevent_var(char **envp, int num_envp, int *cur_index,
263 char *buffer, int buffer_size, int *cur_len,
264 const char *format, ...)
265{
266 va_list args;
267
268 /*
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.
272 */
273 if (*cur_index >= num_envp - 1)
274 return -ENOMEM;
275
276 envp[*cur_index] = buffer + *cur_len;
277
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);
283
284 if (*cur_len > buffer_size)
285 return -ENOMEM;
286
287 (*cur_index)++;
288 return 0;
289}
290EXPORT_SYMBOL_GPL(add_uevent_var);
291
292#if defined(CONFIG_NET)
293static int __init kobject_uevent_init(void)
294{
295 uevent_sock = netlink_kernel_create(NETLINK_KOBJECT_UEVENT, 1, NULL,
296 THIS_MODULE);
297
298 if (!uevent_sock) {
299 printk(KERN_ERR
300 "kobject_uevent: unable to create netlink socket!\n");
301 return -ENODEV;
302 }
303
304 return 0;
305}
306
307postcore_initcall(kobject_uevent_init);
308#endif
309
310#endif /* CONFIG_HOTPLUG */