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-rw-r--r--lib/kobject_uevent.c369
1 files changed, 369 insertions, 0 deletions
diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c
new file mode 100644
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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 <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>
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_uevent.h>
23#include <linux/kobject.h>
24#include <net/sock.h>
25
26#define BUFFER_SIZE 1024 /* buffer for the hotplug env */
27#define NUM_ENVP 32 /* number of env pointers */
28
29#if defined(CONFIG_KOBJECT_UEVENT) || defined(CONFIG_HOTPLUG)
30static char *action_to_string(enum kobject_action action)
31{
32 switch (action) {
33 case KOBJ_ADD:
34 return "add";
35 case KOBJ_REMOVE:
36 return "remove";
37 case KOBJ_CHANGE:
38 return "change";
39 case KOBJ_MOUNT:
40 return "mount";
41 case KOBJ_UMOUNT:
42 return "umount";
43 case KOBJ_OFFLINE:
44 return "offline";
45 case KOBJ_ONLINE:
46 return "online";
47 default:
48 return NULL;
49 }
50}
51#endif
52
53#ifdef CONFIG_KOBJECT_UEVENT
54static struct sock *uevent_sock;
55
56/**
57 * send_uevent - notify userspace by sending event trough netlink socket
58 *
59 * @signal: signal name
60 * @obj: object path (kobject)
61 * @envp: possible hotplug environment to pass with the message
62 * @gfp_mask:
63 */
64static int send_uevent(const char *signal, const char *obj,
65 char **envp, int gfp_mask)
66{
67 struct sk_buff *skb;
68 char *pos;
69 int len;
70
71 if (!uevent_sock)
72 return -EIO;
73
74 len = strlen(signal) + 1;
75 len += strlen(obj) + 1;
76
77 /* allocate buffer with the maximum possible message size */
78 skb = alloc_skb(len + BUFFER_SIZE, gfp_mask);
79 if (!skb)
80 return -ENOMEM;
81
82 pos = skb_put(skb, len);
83 sprintf(pos, "%s@%s", signal, obj);
84
85 /* copy the environment key by key to our continuous buffer */
86 if (envp) {
87 int i;
88
89 for (i = 2; envp[i]; i++) {
90 len = strlen(envp[i]) + 1;
91 pos = skb_put(skb, len);
92 strcpy(pos, envp[i]);
93 }
94 }
95
96 return netlink_broadcast(uevent_sock, skb, 0, 1, gfp_mask);
97}
98
99static int do_kobject_uevent(struct kobject *kobj, enum kobject_action action,
100 struct attribute *attr, int gfp_mask)
101{
102 char *path;
103 char *attrpath;
104 char *signal;
105 int len;
106 int rc = -ENOMEM;
107
108 path = kobject_get_path(kobj, gfp_mask);
109 if (!path)
110 return -ENOMEM;
111
112 signal = action_to_string(action);
113 if (!signal)
114 return -EINVAL;
115
116 if (attr) {
117 len = strlen(path);
118 len += strlen(attr->name) + 2;
119 attrpath = kmalloc(len, gfp_mask);
120 if (!attrpath)
121 goto exit;
122 sprintf(attrpath, "%s/%s", path, attr->name);
123 rc = send_uevent(signal, attrpath, NULL, gfp_mask);
124 kfree(attrpath);
125 } else
126 rc = send_uevent(signal, path, NULL, gfp_mask);
127
128exit:
129 kfree(path);
130 return rc;
131}
132
133/**
134 * kobject_uevent - notify userspace by sending event through netlink socket
135 *
136 * @signal: signal name
137 * @kobj: struct kobject that the event is happening to
138 * @attr: optional struct attribute the event belongs to
139 */
140int kobject_uevent(struct kobject *kobj, enum kobject_action action,
141 struct attribute *attr)
142{
143 return do_kobject_uevent(kobj, action, attr, GFP_KERNEL);
144}
145EXPORT_SYMBOL_GPL(kobject_uevent);
146
147int kobject_uevent_atomic(struct kobject *kobj, enum kobject_action action,
148 struct attribute *attr)
149{
150 return do_kobject_uevent(kobj, action, attr, GFP_ATOMIC);
151}
152EXPORT_SYMBOL_GPL(kobject_uevent_atomic);
153
154static int __init kobject_uevent_init(void)
155{
156 uevent_sock = netlink_kernel_create(NETLINK_KOBJECT_UEVENT, NULL);
157
158 if (!uevent_sock) {
159 printk(KERN_ERR
160 "kobject_uevent: unable to create netlink socket!\n");
161 return -ENODEV;
162 }
163
164 return 0;
165}
166
167postcore_initcall(kobject_uevent_init);
168
169#else
170static inline int send_uevent(const char *signal, const char *obj,
171 char **envp, int gfp_mask)
172{
173 return 0;
174}
175
176#endif /* CONFIG_KOBJECT_UEVENT */
177
178
179#ifdef CONFIG_HOTPLUG
180char hotplug_path[HOTPLUG_PATH_LEN] = "/sbin/hotplug";
181u64 hotplug_seqnum;
182static DEFINE_SPINLOCK(sequence_lock);
183
184/**
185 * kobject_hotplug - notify userspace by executing /sbin/hotplug
186 *
187 * @action: action that is happening (usually "ADD" or "REMOVE")
188 * @kobj: struct kobject that the action is happening to
189 */
190void kobject_hotplug(struct kobject *kobj, enum kobject_action action)
191{
192 char *argv [3];
193 char **envp = NULL;
194 char *buffer = NULL;
195 char *seq_buff;
196 char *scratch;
197 int i = 0;
198 int retval;
199 char *kobj_path = NULL;
200 char *name = NULL;
201 char *action_string;
202 u64 seq;
203 struct kobject *top_kobj = kobj;
204 struct kset *kset;
205 static struct kset_hotplug_ops null_hotplug_ops;
206 struct kset_hotplug_ops *hotplug_ops = &null_hotplug_ops;
207
208 /* If this kobj does not belong to a kset,
209 try to find a parent that does. */
210 if (!top_kobj->kset && top_kobj->parent) {
211 do {
212 top_kobj = top_kobj->parent;
213 } while (!top_kobj->kset && top_kobj->parent);
214 }
215
216 if (top_kobj->kset)
217 kset = top_kobj->kset;
218 else
219 return;
220
221 if (kset->hotplug_ops)
222 hotplug_ops = kset->hotplug_ops;
223
224 /* If the kset has a filter operation, call it.
225 Skip the event, if the filter returns zero. */
226 if (hotplug_ops->filter) {
227 if (!hotplug_ops->filter(kset, kobj))
228 return;
229 }
230
231 pr_debug ("%s\n", __FUNCTION__);
232
233 action_string = action_to_string(action);
234 if (!action_string)
235 return;
236
237 envp = kmalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL);
238 if (!envp)
239 return;
240 memset (envp, 0x00, NUM_ENVP * sizeof (char *));
241
242 buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL);
243 if (!buffer)
244 goto exit;
245
246 if (hotplug_ops->name)
247 name = hotplug_ops->name(kset, kobj);
248 if (name == NULL)
249 name = kset->kobj.name;
250
251 argv [0] = hotplug_path;
252 argv [1] = name;
253 argv [2] = NULL;
254
255 /* minimal command environment */
256 envp [i++] = "HOME=/";
257 envp [i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
258
259 scratch = buffer;
260
261 envp [i++] = scratch;
262 scratch += sprintf(scratch, "ACTION=%s", action_string) + 1;
263
264 kobj_path = kobject_get_path(kobj, GFP_KERNEL);
265 if (!kobj_path)
266 goto exit;
267
268 envp [i++] = scratch;
269 scratch += sprintf (scratch, "DEVPATH=%s", kobj_path) + 1;
270
271 envp [i++] = scratch;
272 scratch += sprintf(scratch, "SUBSYSTEM=%s", name) + 1;
273
274 /* reserve space for the sequence,
275 * put the real one in after the hotplug call */
276 envp[i++] = seq_buff = scratch;
277 scratch += strlen("SEQNUM=18446744073709551616") + 1;
278
279 if (hotplug_ops->hotplug) {
280 /* have the kset specific function add its stuff */
281 retval = hotplug_ops->hotplug (kset, kobj,
282 &envp[i], NUM_ENVP - i, scratch,
283 BUFFER_SIZE - (scratch - buffer));
284 if (retval) {
285 pr_debug ("%s - hotplug() returned %d\n",
286 __FUNCTION__, retval);
287 goto exit;
288 }
289 }
290
291 spin_lock(&sequence_lock);
292 seq = ++hotplug_seqnum;
293 spin_unlock(&sequence_lock);
294 sprintf(seq_buff, "SEQNUM=%llu", (unsigned long long)seq);
295
296 pr_debug ("%s: %s %s seq=%llu %s %s %s %s %s\n",
297 __FUNCTION__, argv[0], argv[1], (unsigned long long)seq,
298 envp[0], envp[1], envp[2], envp[3], envp[4]);
299
300 send_uevent(action_string, kobj_path, envp, GFP_KERNEL);
301
302 if (!hotplug_path[0])
303 goto exit;
304
305 retval = call_usermodehelper (argv[0], argv, envp, 0);
306 if (retval)
307 pr_debug ("%s - call_usermodehelper returned %d\n",
308 __FUNCTION__, retval);
309
310exit:
311 kfree(kobj_path);
312 kfree(buffer);
313 kfree(envp);
314 return;
315}
316EXPORT_SYMBOL(kobject_hotplug);
317
318/**
319 * add_hotplug_env_var - helper for creating hotplug environment variables
320 * @envp: Pointer to table of environment variables, as passed into
321 * hotplug() method.
322 * @num_envp: Number of environment variable slots available, as
323 * passed into hotplug() method.
324 * @cur_index: Pointer to current index into @envp. It should be
325 * initialized to 0 before the first call to add_hotplug_env_var(),
326 * and will be incremented on success.
327 * @buffer: Pointer to buffer for environment variables, as passed
328 * into hotplug() method.
329 * @buffer_size: Length of @buffer, as passed into hotplug() method.
330 * @cur_len: Pointer to current length of space used in @buffer.
331 * Should be initialized to 0 before the first call to
332 * add_hotplug_env_var(), and will be incremented on success.
333 * @format: Format for creating environment variable (of the form
334 * "XXX=%x") for snprintf().
335 *
336 * Returns 0 if environment variable was added successfully or -ENOMEM
337 * if no space was available.
338 */
339int add_hotplug_env_var(char **envp, int num_envp, int *cur_index,
340 char *buffer, int buffer_size, int *cur_len,
341 const char *format, ...)
342{
343 va_list args;
344
345 /*
346 * We check against num_envp - 1 to make sure there is at
347 * least one slot left after we return, since the hotplug
348 * method needs to set the last slot to NULL.
349 */
350 if (*cur_index >= num_envp - 1)
351 return -ENOMEM;
352
353 envp[*cur_index] = buffer + *cur_len;
354
355 va_start(args, format);
356 *cur_len += vsnprintf(envp[*cur_index],
357 max(buffer_size - *cur_len, 0),
358 format, args) + 1;
359 va_end(args);
360
361 if (*cur_len > buffer_size)
362 return -ENOMEM;
363
364 (*cur_index)++;
365 return 0;
366}
367EXPORT_SYMBOL(add_hotplug_env_var);
368
369#endif /* CONFIG_HOTPLUG */
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