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_uevent.h>
23 #include <linux/kobject.h>
26 #define BUFFER_SIZE 1024 /* buffer for the hotplug env */
27 #define NUM_ENVP 32 /* number of env pointers */
29 #if defined(CONFIG_KOBJECT_UEVENT) || defined(CONFIG_HOTPLUG)
30 static char *action_to_string(enum kobject_action action)
53 #ifdef CONFIG_KOBJECT_UEVENT
54 static struct sock *uevent_sock;
57 * send_uevent - notify userspace by sending event through netlink socket
59 * @signal: signal name
60 * @obj: object path (kobject)
61 * @envp: possible hotplug environment to pass with the message
64 static int send_uevent(const char *signal, const char *obj,
65 char **envp, gfp_t gfp_mask)
74 len = strlen(signal) + 1;
75 len += strlen(obj) + 1;
77 /* allocate buffer with the maximum possible message size */
78 skb = alloc_skb(len + BUFFER_SIZE, gfp_mask);
82 pos = skb_put(skb, len);
83 sprintf(pos, "%s@%s", signal, obj);
85 /* copy the environment key by key to our continuous buffer */
89 for (i = 2; envp[i]; i++) {
90 len = strlen(envp[i]) + 1;
91 pos = skb_put(skb, len);
96 NETLINK_CB(skb).dst_group = 1;
97 return netlink_broadcast(uevent_sock, skb, 0, 1, gfp_mask);
100 static int do_kobject_uevent(struct kobject *kobj, enum kobject_action action,
101 struct attribute *attr, gfp_t gfp_mask)
109 path = kobject_get_path(kobj, gfp_mask);
113 signal = action_to_string(action);
119 len += strlen(attr->name) + 2;
120 attrpath = kmalloc(len, gfp_mask);
123 sprintf(attrpath, "%s/%s", path, attr->name);
124 rc = send_uevent(signal, attrpath, NULL, gfp_mask);
127 rc = send_uevent(signal, path, NULL, gfp_mask);
135 * kobject_uevent - notify userspace by sending event through netlink socket
137 * @signal: signal name
138 * @kobj: struct kobject that the event is happening to
139 * @attr: optional struct attribute the event belongs to
141 int kobject_uevent(struct kobject *kobj, enum kobject_action action,
142 struct attribute *attr)
144 return do_kobject_uevent(kobj, action, attr, GFP_KERNEL);
146 EXPORT_SYMBOL_GPL(kobject_uevent);
148 int kobject_uevent_atomic(struct kobject *kobj, enum kobject_action action,
149 struct attribute *attr)
151 return do_kobject_uevent(kobj, action, attr, GFP_ATOMIC);
153 EXPORT_SYMBOL_GPL(kobject_uevent_atomic);
155 static int __init kobject_uevent_init(void)
157 uevent_sock = netlink_kernel_create(NETLINK_KOBJECT_UEVENT, 1, NULL,
162 "kobject_uevent: unable to create netlink socket!\n");
169 postcore_initcall(kobject_uevent_init);
172 static inline int send_uevent(const char *signal, const char *obj,
173 char **envp, int gfp_mask)
178 #endif /* CONFIG_KOBJECT_UEVENT */
181 #ifdef CONFIG_HOTPLUG
182 char hotplug_path[HOTPLUG_PATH_LEN] = "/sbin/hotplug";
184 static DEFINE_SPINLOCK(sequence_lock);
187 * kobject_hotplug - notify userspace by executing /sbin/hotplug
189 * @action: action that is happening (usually "ADD" or "REMOVE")
190 * @kobj: struct kobject that the action is happening to
192 void kobject_hotplug(struct kobject *kobj, enum kobject_action action)
201 char *kobj_path = NULL;
202 const char *name = NULL;
205 struct kobject *top_kobj = kobj;
207 static struct kset_hotplug_ops null_hotplug_ops;
208 struct kset_hotplug_ops *hotplug_ops = &null_hotplug_ops;
210 /* If this kobj does not belong to a kset,
211 try to find a parent that does. */
212 if (!top_kobj->kset && top_kobj->parent) {
214 top_kobj = top_kobj->parent;
215 } while (!top_kobj->kset && top_kobj->parent);
219 kset = top_kobj->kset;
223 if (kset->hotplug_ops)
224 hotplug_ops = kset->hotplug_ops;
226 /* If the kset has a filter operation, call it.
227 Skip the event, if the filter returns zero. */
228 if (hotplug_ops->filter) {
229 if (!hotplug_ops->filter(kset, kobj))
233 pr_debug ("%s\n", __FUNCTION__);
235 action_string = action_to_string(action);
239 envp = kmalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL);
242 memset (envp, 0x00, NUM_ENVP * sizeof (char *));
244 buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL);
248 if (hotplug_ops->name)
249 name = hotplug_ops->name(kset, kobj);
251 name = kobject_name(&kset->kobj);
253 argv [0] = hotplug_path;
254 argv [1] = (char *)name; /* won't be changed but 'const' has to go */
257 /* minimal command environment */
258 envp [i++] = "HOME=/";
259 envp [i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
263 envp [i++] = scratch;
264 scratch += sprintf(scratch, "ACTION=%s", action_string) + 1;
266 kobj_path = kobject_get_path(kobj, GFP_KERNEL);
270 envp [i++] = scratch;
271 scratch += sprintf (scratch, "DEVPATH=%s", kobj_path) + 1;
273 envp [i++] = scratch;
274 scratch += sprintf(scratch, "SUBSYSTEM=%s", name) + 1;
276 /* reserve space for the sequence,
277 * put the real one in after the hotplug call */
278 envp[i++] = seq_buff = scratch;
279 scratch += strlen("SEQNUM=18446744073709551616") + 1;
281 if (hotplug_ops->hotplug) {
282 /* have the kset specific function add its stuff */
283 retval = hotplug_ops->hotplug (kset, kobj,
284 &envp[i], NUM_ENVP - i, scratch,
285 BUFFER_SIZE - (scratch - buffer));
287 pr_debug ("%s - hotplug() returned %d\n",
288 __FUNCTION__, retval);
293 spin_lock(&sequence_lock);
294 seq = ++hotplug_seqnum;
295 spin_unlock(&sequence_lock);
296 sprintf(seq_buff, "SEQNUM=%llu", (unsigned long long)seq);
298 pr_debug ("%s: %s %s seq=%llu %s %s %s %s %s\n",
299 __FUNCTION__, argv[0], argv[1], (unsigned long long)seq,
300 envp[0], envp[1], envp[2], envp[3], envp[4]);
302 send_uevent(action_string, kobj_path, envp, GFP_KERNEL);
304 if (!hotplug_path[0])
307 retval = call_usermodehelper (argv[0], argv, envp, 0);
309 pr_debug ("%s - call_usermodehelper returned %d\n",
310 __FUNCTION__, retval);
318 EXPORT_SYMBOL(kobject_hotplug);
321 * add_hotplug_env_var - helper for creating hotplug environment variables
322 * @envp: Pointer to table of environment variables, as passed into
324 * @num_envp: Number of environment variable slots available, as
325 * passed into hotplug() method.
326 * @cur_index: Pointer to current index into @envp. It should be
327 * initialized to 0 before the first call to add_hotplug_env_var(),
328 * and will be incremented on success.
329 * @buffer: Pointer to buffer for environment variables, as passed
330 * into hotplug() method.
331 * @buffer_size: Length of @buffer, as passed into hotplug() method.
332 * @cur_len: Pointer to current length of space used in @buffer.
333 * Should be initialized to 0 before the first call to
334 * add_hotplug_env_var(), and will be incremented on success.
335 * @format: Format for creating environment variable (of the form
336 * "XXX=%x") for snprintf().
338 * Returns 0 if environment variable was added successfully or -ENOMEM
339 * if no space was available.
341 int add_hotplug_env_var(char **envp, int num_envp, int *cur_index,
342 char *buffer, int buffer_size, int *cur_len,
343 const char *format, ...)
348 * We check against num_envp - 1 to make sure there is at
349 * least one slot left after we return, since the hotplug
350 * method needs to set the last slot to NULL.
352 if (*cur_index >= num_envp - 1)
355 envp[*cur_index] = buffer + *cur_len;
357 va_start(args, format);
358 *cur_len += vsnprintf(envp[*cur_index],
359 max(buffer_size - *cur_len, 0),
363 if (*cur_len > buffer_size)
369 EXPORT_SYMBOL(add_hotplug_env_var);
371 #endif /* CONFIG_HOTPLUG */