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.h>
25 #define BUFFER_SIZE 1024 /* buffer for the variables */
26 #define NUM_ENVP 32 /* number of env pointers */
28 #if defined(CONFIG_HOTPLUG)
29 char uevent_helper[UEVENT_HELPER_PATH_LEN] = "/sbin/hotplug";
31 static DEFINE_SPINLOCK(sequence_lock);
32 static struct sock *uevent_sock;
34 static char *action_to_string(enum kobject_action action)
53 * kobject_uevent - notify userspace by ending an uevent
55 * @action: action that is happening (usually KOBJ_ADD and KOBJ_REMOVE)
56 * @kobj: struct kobject that the action is happening to
58 void kobject_uevent(struct kobject *kobj, enum kobject_action action)
63 const char *action_string;
64 const char *devpath = NULL;
65 const char *subsystem;
66 struct kobject *top_kobj;
68 struct kset_uevent_ops *uevent_ops;
74 pr_debug("%s\n", __FUNCTION__);
76 action_string = action_to_string(action);
80 /* search the kset we belong to */
82 if (!top_kobj->kset && top_kobj->parent) {
84 top_kobj = top_kobj->parent;
85 } while (!top_kobj->kset && top_kobj->parent);
90 kset = top_kobj->kset;
91 uevent_ops = kset->uevent_ops;
93 /* skip the event, if the filter returns zero. */
94 if (uevent_ops && uevent_ops->filter)
95 if (!uevent_ops->filter(kset, kobj))
98 /* environment index */
99 envp = kzalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL);
103 /* environment values */
104 buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL);
108 /* complete object path */
109 devpath = kobject_get_path(kobj, GFP_KERNEL);
113 /* originating subsystem */
114 if (uevent_ops && uevent_ops->name)
115 subsystem = uevent_ops->name(kset, kobj);
117 subsystem = kobject_name(&kset->kobj);
119 /* event environemnt for helper process only */
120 envp[i++] = "HOME=/";
121 envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
125 envp [i++] = scratch;
126 scratch += sprintf(scratch, "ACTION=%s", action_string) + 1;
127 envp [i++] = scratch;
128 scratch += sprintf (scratch, "DEVPATH=%s", devpath) + 1;
129 envp [i++] = scratch;
130 scratch += sprintf(scratch, "SUBSYSTEM=%s", subsystem) + 1;
132 /* just reserve the space, overwrite it after kset call has returned */
133 envp[i++] = seq_buff = scratch;
134 scratch += strlen("SEQNUM=18446744073709551616") + 1;
136 /* let the kset specific function add its stuff */
137 if (uevent_ops && uevent_ops->uevent) {
138 retval = uevent_ops->uevent(kset, kobj,
139 &envp[i], NUM_ENVP - i, scratch,
140 BUFFER_SIZE - (scratch - buffer));
142 pr_debug ("%s - uevent() returned %d\n",
143 __FUNCTION__, retval);
148 /* we will send an event, request a new sequence number */
149 spin_lock(&sequence_lock);
150 seq = ++uevent_seqnum;
151 spin_unlock(&sequence_lock);
152 sprintf(seq_buff, "SEQNUM=%llu", (unsigned long long)seq);
154 /* send netlink message */
159 /* allocate message with the maximum possible size */
160 len = strlen(action_string) + strlen(devpath) + 2;
161 skb = alloc_skb(len + BUFFER_SIZE, GFP_KERNEL);
164 scratch = skb_put(skb, len);
165 sprintf(scratch, "%s@%s", action_string, devpath);
167 /* copy keys to our continuous event payload buffer */
168 for (i = 2; envp[i]; i++) {
169 len = strlen(envp[i]) + 1;
170 scratch = skb_put(skb, len);
171 strcpy(scratch, envp[i]);
174 NETLINK_CB(skb).dst_group = 1;
175 netlink_broadcast(uevent_sock, skb, 0, 1, GFP_KERNEL);
179 /* call uevent_helper, usually only enabled during early boot */
180 if (uevent_helper[0]) {
183 argv [0] = uevent_helper;
184 argv [1] = (char *)subsystem;
186 call_usermodehelper (argv[0], argv, envp, 0);
195 EXPORT_SYMBOL_GPL(kobject_uevent);
198 * add_uevent_var - helper for creating event variables
199 * @envp: Pointer to table of environment variables, as passed into
201 * @num_envp: Number of environment variable slots available, as
202 * passed into uevent() method.
203 * @cur_index: Pointer to current index into @envp. It should be
204 * initialized to 0 before the first call to add_uevent_var(),
205 * and will be incremented on success.
206 * @buffer: Pointer to buffer for environment variables, as passed
207 * into uevent() method.
208 * @buffer_size: Length of @buffer, as passed into uevent() method.
209 * @cur_len: Pointer to current length of space used in @buffer.
210 * Should be initialized to 0 before the first call to
211 * add_uevent_var(), and will be incremented on success.
212 * @format: Format for creating environment variable (of the form
213 * "XXX=%x") for snprintf().
215 * Returns 0 if environment variable was added successfully or -ENOMEM
216 * if no space was available.
218 int add_uevent_var(char **envp, int num_envp, int *cur_index,
219 char *buffer, int buffer_size, int *cur_len,
220 const char *format, ...)
225 * We check against num_envp - 1 to make sure there is at
226 * least one slot left after we return, since kobject_uevent()
227 * needs to set the last slot to NULL.
229 if (*cur_index >= num_envp - 1)
232 envp[*cur_index] = buffer + *cur_len;
234 va_start(args, format);
235 *cur_len += vsnprintf(envp[*cur_index],
236 max(buffer_size - *cur_len, 0),
240 if (*cur_len > buffer_size)
246 EXPORT_SYMBOL_GPL(add_uevent_var);
248 static int __init kobject_uevent_init(void)
250 uevent_sock = netlink_kernel_create(NETLINK_KOBJECT_UEVENT, 1, NULL,
255 "kobject_uevent: unable to create netlink socket!\n");
262 postcore_initcall(kobject_uevent_init);
264 #endif /* CONFIG_HOTPLUG */