[mirror_ubuntu-artful-kernel.git] / lib / kobject_uevent.c

/*
 * kernel userspace event delivery
 *
 * Copyright (C) 2004 Red Hat, Inc.  All rights reserved.
 * Copyright (C) 2004 Novell, Inc.  All rights reserved.
 * Copyright (C) 2004 IBM, Inc. All rights reserved.
 *
 * Licensed under the GNU GPL v2.
 *
 * Authors:
 *	Robert Love		<rml@novell.com>
 *	Kay Sievers		<kay.sievers@vrfy.org>
 *	Arjan van de Ven	<arjanv@redhat.com>
 *	Greg Kroah-Hartman	<greg@kroah.com>
 */

#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/kobject.h>
#include <linux/module.h>
#include <linux/slab.h>

#include <linux/socket.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <net/sock.h>
#include <net/net_namespace.h>


u64 uevent_seqnum;
char uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH;
static DEFINE_SPINLOCK(sequence_lock);
#ifdef CONFIG_NET
struct uevent_sock {
	struct list_head list;
	struct sock *sk;
};
static LIST_HEAD(uevent_sock_list);
static DEFINE_MUTEX(uevent_sock_mutex);
#endif

/* the strings here must match the enum in include/linux/kobject.h */
static const char *kobject_actions[] = {
	[KOBJ_ADD] =		"add",
	[KOBJ_REMOVE] =		"remove",
	[KOBJ_CHANGE] =		"change",
	[KOBJ_MOVE] =		"move",
	[KOBJ_ONLINE] =		"online",
	[KOBJ_OFFLINE] =	"offline",
};

/**
 * kobject_action_type - translate action string to numeric type
 *
 * @buf: buffer containing the action string, newline is ignored
 * @len: length of buffer
 * @type: pointer to the location to store the action type
 *
 * Returns 0 if the action string was recognized.
 */
int kobject_action_type(const char *buf, size_t count,
			enum kobject_action *type)
{
	enum kobject_action action;
	int ret = -EINVAL;

	if (count && (buf[count-1] == '\n' || buf[count-1] == '\0'))
		count--;

	if (!count)
		goto out;

	for (action = 0; action < ARRAY_SIZE(kobject_actions); action++) {
		if (strncmp(kobject_actions[action], buf, count) != 0)
			continue;
		if (kobject_actions[action][count] != '\0')
			continue;
		*type = action;
		ret = 0;
		break;
	}
out:
	return ret;
}

/**
 * kobject_uevent_env - send an uevent with environmental data
 *
 * @action: action that is happening
 * @kobj: struct kobject that the action is happening to
 * @envp_ext: pointer to environmental data
 *
 * Returns 0 if kobject_uevent() is completed with success or the
 * corresponding error when it fails.
 */
int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
		       char *envp_ext[])
{
	struct kobj_uevent_env *env;
	const char *action_string = kobject_actions[action];
	const char *devpath = NULL;
	const char *subsystem;
	struct kobject *top_kobj;
	struct kset *kset;
	const struct kset_uevent_ops *uevent_ops;
	u64 seq;
	int i = 0;
	int retval = 0;
#ifdef CONFIG_NET
	struct uevent_sock *ue_sk;
#endif

	pr_debug("kobject: '%s' (%p): %s\n",
		 kobject_name(kobj), kobj, __func__);

	/* search the kset we belong to */
	top_kobj = kobj;
	while (!top_kobj->kset && top_kobj->parent)
		top_kobj = top_kobj->parent;

	if (!top_kobj->kset) {
		pr_debug("kobject: '%s' (%p): %s: attempted to send uevent "
			 "without kset!\n", kobject_name(kobj), kobj,
			 __func__);
		return -EINVAL;
	}

	kset = top_kobj->kset;
	uevent_ops = kset->uevent_ops;

	/* skip the event, if uevent_suppress is set*/
	if (kobj->uevent_suppress) {
		pr_debug("kobject: '%s' (%p): %s: uevent_suppress "
				 "caused the event to drop!\n",
				 kobject_name(kobj), kobj, __func__);
		return 0;
	}
	/* skip the event, if the filter returns zero. */
	if (uevent_ops && uevent_ops->filter)
		if (!uevent_ops->filter(kset, kobj)) {
			pr_debug("kobject: '%s' (%p): %s: filter function "
				 "caused the event to drop!\n",
				 kobject_name(kobj), kobj, __func__);
			return 0;
		}

	/* originating subsystem */
	if (uevent_ops && uevent_ops->name)
		subsystem = uevent_ops->name(kset, kobj);
	else
		subsystem = kobject_name(&kset->kobj);
	if (!subsystem) {
		pr_debug("kobject: '%s' (%p): %s: unset subsystem caused the "
			 "event to drop!\n", kobject_name(kobj), kobj,
			 __func__);
		return 0;
	}

	/* environment buffer */
	env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
	if (!env)
		return -ENOMEM;

	/* complete object path */
	devpath = kobject_get_path(kobj, GFP_KERNEL);
	if (!devpath) {
		retval = -ENOENT;
		goto exit;
	}

	/* default keys */
	retval = add_uevent_var(env, "ACTION=%s", action_string);
	if (retval)
		goto exit;
	retval = add_uevent_var(env, "DEVPATH=%s", devpath);
	if (retval)
		goto exit;
	retval = add_uevent_var(env, "SUBSYSTEM=%s", subsystem);
	if (retval)
		goto exit;

	/* keys passed in from the caller */
	if (envp_ext) {
		for (i = 0; envp_ext[i]; i++) {
			retval = add_uevent_var(env, "%s", envp_ext[i]);
			if (retval)
				goto exit;
		}
	}

	/* let the kset specific function add its stuff */
	if (uevent_ops && uevent_ops->uevent) {
		retval = uevent_ops->uevent(kset, kobj, env);
		if (retval) {
			pr_debug("kobject: '%s' (%p): %s: uevent() returned "
				 "%d\n", kobject_name(kobj), kobj,
				 __func__, retval);
			goto exit;
		}
	}

	/*
	 * Mark "add" and "remove" events in the object to ensure proper
	 * events to userspace during automatic cleanup. If the object did
	 * send an "add" event, "remove" will automatically generated by
	 * the core, if not already done by the caller.
	 */
	if (action == KOBJ_ADD)
		kobj->state_add_uevent_sent = 1;
	else if (action == KOBJ_REMOVE)
		kobj->state_remove_uevent_sent = 1;

	/* we will send an event, so request a new sequence number */
	spin_lock(&sequence_lock);
	seq = ++uevent_seqnum;
	spin_unlock(&sequence_lock);
	retval = add_uevent_var(env, "SEQNUM=%llu", (unsigned long long)seq);
	if (retval)
		goto exit;

#if defined(CONFIG_NET)
	/* send netlink message */
	mutex_lock(&uevent_sock_mutex);
	list_for_each_entry(ue_sk, &uevent_sock_list, list) {
		struct sock *uevent_sock = ue_sk->sk;
		struct sk_buff *skb;
		size_t len;

		/* allocate message with the maximum possible size */
		len = strlen(action_string) + strlen(devpath) + 2;
		skb = alloc_skb(len + env->buflen, GFP_KERNEL);
		if (skb) {
			char *scratch;

			/* add header */
			scratch = skb_put(skb, len);
			sprintf(scratch, "%s@%s", action_string, devpath);

			/* copy keys to our continuous event payload buffer */
			for (i = 0; i < env->envp_idx; i++) {
				len = strlen(env->envp[i]) + 1;
				scratch = skb_put(skb, len);
				strcpy(scratch, env->envp[i]);
			}

			NETLINK_CB(skb).dst_group = 1;
			retval = netlink_broadcast(uevent_sock, skb, 0, 1,
						   GFP_KERNEL);
			/* ENOBUFS should be handled in userspace */
			if (retval == -ENOBUFS)
				retval = 0;
		} else
			retval = -ENOMEM;
	}
	mutex_unlock(&uevent_sock_mutex);
#endif

	/* call uevent_helper, usually only enabled during early boot */
	if (uevent_helper[0]) {
		char *argv [3];

		argv [0] = uevent_helper;
		argv [1] = (char *)subsystem;
		argv [2] = NULL;
		retval = add_uevent_var(env, "HOME=/");
		if (retval)
			goto exit;
		retval = add_uevent_var(env,
					"PATH=/sbin:/bin:/usr/sbin:/usr/bin");
		if (retval)
			goto exit;

		retval = call_usermodehelper(argv[0], argv,
					     env->envp, UMH_WAIT_EXEC);
	}

exit:
	kfree(devpath);
	kfree(env);
	return retval;
}
EXPORT_SYMBOL_GPL(kobject_uevent_env);

/**
 * kobject_uevent - notify userspace by ending an uevent
 *
 * @action: action that is happening
 * @kobj: struct kobject that the action is happening to
 *
 * Returns 0 if kobject_uevent() is completed with success or the
 * corresponding error when it fails.
 */
int kobject_uevent(struct kobject *kobj, enum kobject_action action)
{
	return kobject_uevent_env(kobj, action, NULL);
}
EXPORT_SYMBOL_GPL(kobject_uevent);

/**
 * add_uevent_var - add key value string to the environment buffer
 * @env: environment buffer structure
 * @format: printf format for the key=value pair
 *
 * Returns 0 if environment variable was added successfully or -ENOMEM
 * if no space was available.
 */
int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
{
	va_list args;
	int len;

	if (env->envp_idx >= ARRAY_SIZE(env->envp)) {
		WARN(1, KERN_ERR "add_uevent_var: too many keys\n");
		return -ENOMEM;
	}

	va_start(args, format);
	len = vsnprintf(&env->buf[env->buflen],
			sizeof(env->buf) - env->buflen,
			format, args);
	va_end(args);

	if (len >= (sizeof(env->buf) - env->buflen)) {
		WARN(1, KERN_ERR "add_uevent_var: buffer size too small\n");
		return -ENOMEM;
	}

	env->envp[env->envp_idx++] = &env->buf[env->buflen];
	env->buflen += len + 1;
	return 0;
}
EXPORT_SYMBOL_GPL(add_uevent_var);

#if defined(CONFIG_NET)
static int uevent_net_init(struct net *net)
{
	struct uevent_sock *ue_sk;

	ue_sk = kzalloc(sizeof(*ue_sk), GFP_KERNEL);
	if (!ue_sk)
		return -ENOMEM;

	ue_sk->sk = netlink_kernel_create(net, NETLINK_KOBJECT_UEVENT,
					  1, NULL, NULL, THIS_MODULE);
	if (!ue_sk->sk) {
		printk(KERN_ERR
		       "kobject_uevent: unable to create netlink socket!\n");
		return -ENODEV;
	}
	mutex_lock(&uevent_sock_mutex);
	list_add_tail(&ue_sk->list, &uevent_sock_list);
	mutex_unlock(&uevent_sock_mutex);
	return 0;
}

static void uevent_net_exit(struct net *net)
{
	struct uevent_sock *ue_sk;

	mutex_lock(&uevent_sock_mutex);
	list_for_each_entry(ue_sk, &uevent_sock_list, list) {
		if (sock_net(ue_sk->sk) == net)
			goto found;
	}
	mutex_unlock(&uevent_sock_mutex);
	return;

found:
	list_del(&ue_sk->list);
	mutex_unlock(&uevent_sock_mutex);

	netlink_kernel_release(ue_sk->sk);
	kfree(ue_sk);
}

static struct pernet_operations uevent_net_ops = {
	.init	= uevent_net_init,
	.exit	= uevent_net_exit,
};

static int __init kobject_uevent_init(void)
{
	netlink_set_nonroot(NETLINK_KOBJECT_UEVENT, NL_NONROOT_RECV);
	return register_pernet_subsys(&uevent_net_ops);
}


postcore_initcall(kobject_uevent_init);
#endif
Commit	Line	Data
1da177e4 LT	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>
2d38f9a4 DL	18	#include <linux/string.h>
	19	#include <linux/kobject.h>
	20	#include <linux/module.h>
5a0e3ad6	21	#include <linux/slab.h>
2d38f9a4	22
1da177e4 LT	23	#include <linux/socket.h>
	24	#include <linux/skbuff.h>
	25	#include <linux/netlink.h>
1da177e4	26	#include <net/sock.h>
07e98962	27	#include <net/net_namespace.h>
1da177e4	28
1da177e4	29
cd030c4c	30	u64 uevent_seqnum;
6a8d8abb	31	char uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH;
cd030c4c	32	static DEFINE_SPINLOCK(sequence_lock);
07e98962 EB	33	#ifdef CONFIG_NET
	34	struct uevent_sock {
	35	struct list_head list;
	36	struct sock *sk;
	37	};
	38	static LIST_HEAD(uevent_sock_list);
	39	static DEFINE_MUTEX(uevent_sock_mutex);
cd030c4c CH	40	#endif
cd030c4c CH	41
5c5daf65 KS	42	/* the strings here must match the enum in include/linux/kobject.h */
	43	static const char *kobject_actions[] = {
	44	[KOBJ_ADD] = "add",
	45	[KOBJ_REMOVE] = "remove",
	46	[KOBJ_CHANGE] = "change",
	47	[KOBJ_MOVE] = "move",
	48	[KOBJ_ONLINE] = "online",
	49	[KOBJ_OFFLINE] = "offline",
	50	};
	51
	52	/**
	53	* kobject_action_type - translate action string to numeric type
	54	*
	55	* @buf: buffer containing the action string, newline is ignored
	56	* @len: length of buffer
	57	* @type: pointer to the location to store the action type
	58	*
	59	* Returns 0 if the action string was recognized.
	60	*/
	61	int kobject_action_type(const char *buf, size_t count,
	62	enum kobject_action *type)
	63	{
	64	enum kobject_action action;
	65	int ret = -EINVAL;
	66
a9edadbf	67	if (count && (buf[count-1] == '\n' \|\| buf[count-1] == '\0'))
5c5daf65 KS	68	count--;
	69
	70	if (!count)
	71	goto out;
	72
	73	for (action = 0; action < ARRAY_SIZE(kobject_actions); action++) {
	74	if (strncmp(kobject_actions[action], buf, count) != 0)
	75	continue;
	76	if (kobject_actions[action][count] != '\0')
	77	continue;
	78	*type = action;
	79	ret = 0;
	80	break;
	81	}
	82	out:
	83	return ret;
	84	}
	85
1da177e4	86	/**
8a82472f	87	* kobject_uevent_env - send an uevent with environmental data
1da177e4	88	*
ccd490a3	89	* @action: action that is happening
1da177e4	90	* @kobj: struct kobject that the action is happening to
8a82472f	91	* @envp_ext: pointer to environmental data
542cfce6 AK	92	*
	93	* Returns 0 if kobject_uevent() is completed with success or the
	94	* corresponding error when it fails.
1da177e4	95	*/
542cfce6	96	int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
7eff2e7a	97	char *envp_ext[])
1da177e4	98	{
7eff2e7a KS	99	struct kobj_uevent_env *env;
7eff2e7a KS	100	const char *action_string = kobject_actions[action];
5f123fbd KS	101	const char *devpath = NULL;
	102	const char *subsystem;
	103	struct kobject *top_kobj;
	104	struct kset *kset;
9cd43611	105	const struct kset_uevent_ops *uevent_ops;
5f123fbd	106	u64 seq;
1da177e4	107	int i = 0;
542cfce6	108	int retval = 0;
07e98962 EB	109	#ifdef CONFIG_NET
	110	struct uevent_sock *ue_sk;
	111	#endif
1da177e4	112
9f66fa2a	113	pr_debug("kobject: '%s' (%p): %s\n",
810304db	114	kobject_name(kobj), kobj, __func__);
5f123fbd	115
5f123fbd KS	116	/* search the kset we belong to */
5f123fbd KS	117	top_kobj = kobj;
ccd490a3	118	while (!top_kobj->kset && top_kobj->parent)
14193fb9	119	top_kobj = top_kobj->parent;
ccd490a3	120
542cfce6	121	if (!top_kobj->kset) {
9f66fa2a GKH	122	pr_debug("kobject: '%s' (%p): %s: attempted to send uevent "
9f66fa2a GKH	123	"without kset!\n", kobject_name(kobj), kobj,
810304db	124	__func__);
542cfce6 AK	125	return -EINVAL;
542cfce6 AK	126	}
1da177e4	127
5f123fbd	128	kset = top_kobj->kset;
312c004d	129	uevent_ops = kset->uevent_ops;
1da177e4	130
f67f129e ML	131	/* skip the event, if uevent_suppress is set*/
	132	if (kobj->uevent_suppress) {
	133	pr_debug("kobject: '%s' (%p): %s: uevent_suppress "
	134	"caused the event to drop!\n",
	135	kobject_name(kobj), kobj, __func__);
	136	return 0;
	137	}
7eff2e7a	138	/* skip the event, if the filter returns zero. */
312c004d	139	if (uevent_ops && uevent_ops->filter)
542cfce6	140	if (!uevent_ops->filter(kset, kobj)) {
9f66fa2a GKH	141	pr_debug("kobject: '%s' (%p): %s: filter function "
9f66fa2a GKH	142	"caused the event to drop!\n",
810304db	143	kobject_name(kobj), kobj, __func__);
542cfce6 AK	144	return 0;
542cfce6 AK	145	}
1da177e4	146
86406245 KS	147	/* originating subsystem */
	148	if (uevent_ops && uevent_ops->name)
	149	subsystem = uevent_ops->name(kset, kobj);
	150	else
	151	subsystem = kobject_name(&kset->kobj);
	152	if (!subsystem) {
9f66fa2a GKH	153	pr_debug("kobject: '%s' (%p): %s: unset subsystem caused the "
9f66fa2a GKH	154	"event to drop!\n", kobject_name(kobj), kobj,
810304db	155	__func__);
86406245 KS	156	return 0;
	157	}
	158
7eff2e7a KS	159	/* environment buffer */
	160	env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
	161	if (!env)
542cfce6	162	return -ENOMEM;
1da177e4	163
5f123fbd KS	164	/* complete object path */
5f123fbd KS	165	devpath = kobject_get_path(kobj, GFP_KERNEL);
542cfce6 AK	166	if (!devpath) {
542cfce6 AK	167	retval = -ENOENT;
5f123fbd	168	goto exit;
542cfce6	169	}
1da177e4	170
5f123fbd	171	/* default keys */
7eff2e7a KS	172	retval = add_uevent_var(env, "ACTION=%s", action_string);
	173	if (retval)
	174	goto exit;
	175	retval = add_uevent_var(env, "DEVPATH=%s", devpath);
	176	if (retval)
	177	goto exit;
	178	retval = add_uevent_var(env, "SUBSYSTEM=%s", subsystem);
	179	if (retval)
	180	goto exit;
	181
	182	/* keys passed in from the caller */
	183	if (envp_ext) {
	184	for (i = 0; envp_ext[i]; i++) {
c65b9145	185	retval = add_uevent_var(env, "%s", envp_ext[i]);
7eff2e7a KS	186	if (retval)
	187	goto exit;
	188	}
	189	}
1da177e4	190
5f123fbd	191	/* let the kset specific function add its stuff */
312c004d	192	if (uevent_ops && uevent_ops->uevent) {
7eff2e7a	193	retval = uevent_ops->uevent(kset, kobj, env);
1da177e4	194	if (retval) {
9f66fa2a GKH	195	pr_debug("kobject: '%s' (%p): %s: uevent() returned "
9f66fa2a GKH	196	"%d\n", kobject_name(kobj), kobj,
810304db	197	__func__, retval);
1da177e4 LT	198	goto exit;
	199	}
	200	}
	201
0f4dafc0 KS	202	/*
	203	* Mark "add" and "remove" events in the object to ensure proper
	204	* events to userspace during automatic cleanup. If the object did
	205	* send an "add" event, "remove" will automatically generated by
	206	* the core, if not already done by the caller.
	207	*/
	208	if (action == KOBJ_ADD)
	209	kobj->state_add_uevent_sent = 1;
	210	else if (action == KOBJ_REMOVE)
	211	kobj->state_remove_uevent_sent = 1;
	212
7eff2e7a	213	/* we will send an event, so request a new sequence number */
1da177e4	214	spin_lock(&sequence_lock);
312c004d	215	seq = ++uevent_seqnum;
1da177e4	216	spin_unlock(&sequence_lock);
7eff2e7a KS	217	retval = add_uevent_var(env, "SEQNUM=%llu", (unsigned long long)seq);
	218	if (retval)
	219	goto exit;
1da177e4	220
4d17ffda	221	#if defined(CONFIG_NET)
5f123fbd	222	/* send netlink message */
07e98962 EB	223	mutex_lock(&uevent_sock_mutex);
	224	list_for_each_entry(ue_sk, &uevent_sock_list, list) {
	225	struct sock *uevent_sock = ue_sk->sk;
5f123fbd KS	226	struct sk_buff *skb;
	227	size_t len;
	228
	229	/* allocate message with the maximum possible size */
	230	len = strlen(action_string) + strlen(devpath) + 2;
7eff2e7a	231	skb = alloc_skb(len + env->buflen, GFP_KERNEL);
5f123fbd	232	if (skb) {
7eff2e7a KS	233	char *scratch;
7eff2e7a KS	234
5f123fbd KS	235	/* add header */
	236	scratch = skb_put(skb, len);
	237	sprintf(scratch, "%s@%s", action_string, devpath);
	238
	239	/* copy keys to our continuous event payload buffer */
7eff2e7a KS	240	for (i = 0; i < env->envp_idx; i++) {
7eff2e7a KS	241	len = strlen(env->envp[i]) + 1;
5f123fbd	242	scratch = skb_put(skb, len);
7eff2e7a	243	strcpy(scratch, env->envp[i]);
5f123fbd KS	244	}
	245
	246	NETLINK_CB(skb).dst_group = 1;
e0d7bf5d ML	247	retval = netlink_broadcast(uevent_sock, skb, 0, 1,
e0d7bf5d ML	248	GFP_KERNEL);
ff491a73 PNA	249	/* ENOBUFS should be handled in userspace */
	250	if (retval == -ENOBUFS)
	251	retval = 0;
e0d7bf5d ML	252	} else
e0d7bf5d ML	253	retval = -ENOMEM;
5f123fbd	254	}
07e98962	255	mutex_unlock(&uevent_sock_mutex);
4d17ffda	256	#endif
1da177e4	257
5f123fbd	258	/* call uevent_helper, usually only enabled during early boot */
312c004d	259	if (uevent_helper[0]) {
5f123fbd	260	char *argv [3];
1da177e4	261
312c004d	262	argv [0] = uevent_helper;
5f123fbd KS	263	argv [1] = (char *)subsystem;
5f123fbd KS	264	argv [2] = NULL;
7eff2e7a KS	265	retval = add_uevent_var(env, "HOME=/");
	266	if (retval)
	267	goto exit;
e374a2bf GKH	268	retval = add_uevent_var(env,
e374a2bf GKH	269	"PATH=/sbin:/bin:/usr/sbin:/usr/bin");
7eff2e7a KS	270	if (retval)
	271	goto exit;
	272
0ad1d6f3	273	retval = call_usermodehelper(argv[0], argv,
05f54c13	274	env->envp, UMH_WAIT_EXEC);
5f123fbd	275	}
1da177e4 LT	276
1da177e4 LT	277	exit:
5f123fbd	278	kfree(devpath);
7eff2e7a	279	kfree(env);
542cfce6	280	return retval;
1da177e4	281	}
8a82472f CH	282	EXPORT_SYMBOL_GPL(kobject_uevent_env);
	283
	284	/**
	285	* kobject_uevent - notify userspace by ending an uevent
	286	*
ccd490a3	287	* @action: action that is happening
8a82472f	288	* @kobj: struct kobject that the action is happening to
542cfce6 AK	289	*
	290	* Returns 0 if kobject_uevent() is completed with success or the
	291	* corresponding error when it fails.
8a82472f	292	*/
542cfce6	293	int kobject_uevent(struct kobject *kobj, enum kobject_action action)
8a82472f	294	{
542cfce6	295	return kobject_uevent_env(kobj, action, NULL);
8a82472f	296	}
312c004d	297	EXPORT_SYMBOL_GPL(kobject_uevent);
1da177e4 LT	298
1da177e4 LT	299	/**
7eff2e7a KS	300	* add_uevent_var - add key value string to the environment buffer
	301	* @env: environment buffer structure
	302	* @format: printf format for the key=value pair
1da177e4 LT	303	*
	304	* Returns 0 if environment variable was added successfully or -ENOMEM
	305	* if no space was available.
	306	*/
7eff2e7a	307	int add_uevent_var(struct kobj_uevent_env env, const char format, ...)
1da177e4 LT	308	{
1da177e4 LT	309	va_list args;
7eff2e7a	310	int len;
1da177e4	311
7eff2e7a	312	if (env->envp_idx >= ARRAY_SIZE(env->envp)) {
5cd2b459	313	WARN(1, KERN_ERR "add_uevent_var: too many keys\n");
1da177e4	314	return -ENOMEM;
7eff2e7a	315	}
1da177e4 LT	316
1da177e4 LT	317	va_start(args, format);
7eff2e7a KS	318	len = vsnprintf(&env->buf[env->buflen],
	319	sizeof(env->buf) - env->buflen,
	320	format, args);
1da177e4 LT	321	va_end(args);
1da177e4 LT	322
7eff2e7a	323	if (len >= (sizeof(env->buf) - env->buflen)) {
5cd2b459	324	WARN(1, KERN_ERR "add_uevent_var: buffer size too small\n");
1da177e4	325	return -ENOMEM;
7eff2e7a	326	}
1da177e4	327
7eff2e7a KS	328	env->envp[env->envp_idx++] = &env->buf[env->buflen];
7eff2e7a KS	329	env->buflen += len + 1;
1da177e4 LT	330	return 0;
1da177e4 LT	331	}
312c004d	332	EXPORT_SYMBOL_GPL(add_uevent_var);
1da177e4	333
4d17ffda	334	#if defined(CONFIG_NET)
07e98962	335	static int uevent_net_init(struct net *net)
5f123fbd	336	{
07e98962 EB	337	struct uevent_sock *ue_sk;
	338
	339	ue_sk = kzalloc(sizeof(*ue_sk), GFP_KERNEL);
	340	if (!ue_sk)
	341	return -ENOMEM;
	342
	343	ue_sk->sk = netlink_kernel_create(net, NETLINK_KOBJECT_UEVENT,
	344	1, NULL, NULL, THIS_MODULE);
	345	if (!ue_sk->sk) {
5f123fbd KS	346	printk(KERN_ERR
	347	"kobject_uevent: unable to create netlink socket!\n");
	348	return -ENODEV;
	349	}
07e98962 EB	350	mutex_lock(&uevent_sock_mutex);
	351	list_add_tail(&ue_sk->list, &uevent_sock_list);
	352	mutex_unlock(&uevent_sock_mutex);
5f123fbd KS	353	return 0;
	354	}
	355
07e98962 EB	356	static void uevent_net_exit(struct net *net)
	357	{
	358	struct uevent_sock *ue_sk;
	359
	360	mutex_lock(&uevent_sock_mutex);
	361	list_for_each_entry(ue_sk, &uevent_sock_list, list) {
	362	if (sock_net(ue_sk->sk) == net)
	363	goto found;
	364	}
	365	mutex_unlock(&uevent_sock_mutex);
	366	return;
	367
	368	found:
	369	list_del(&ue_sk->list);
	370	mutex_unlock(&uevent_sock_mutex);
	371
	372	netlink_kernel_release(ue_sk->sk);
	373	kfree(ue_sk);
	374	}
	375
	376	static struct pernet_operations uevent_net_ops = {
	377	.init = uevent_net_init,
	378	.exit = uevent_net_exit,
	379	};
	380
	381	static int __init kobject_uevent_init(void)
	382	{
	383	netlink_set_nonroot(NETLINK_KOBJECT_UEVENT, NL_NONROOT_RECV);
	384	return register_pernet_subsys(&uevent_net_ops);
	385	}
	386
	387
5f123fbd	388	postcore_initcall(kobject_uevent_init);
4d17ffda	389	#endif