[linux.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		<[email protected]>
 *	Kay Sievers		<[email protected]>
 *	Arjan van de Ven	<[email protected]>
 *	Greg Kroah-Hartman	<[email protected]>
 */

#include <linux/spinlock.h>
#include <linux/socket.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <linux/string.h>
#include <linux/kobject.h>
#include <net/sock.h>


u64 uevent_seqnum;
char uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH;
static DEFINE_SPINLOCK(sequence_lock);
#if defined(CONFIG_NET)
static struct sock *uevent_sock;
#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')
		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;
	struct kset_uevent_ops *uevent_ops;
	u64 seq;
	int i = 0;
	int retval = 0;

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

	/* 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,
			 __FUNCTION__);
		return -EINVAL;
	}

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

	/* 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, __FUNCTION__);
			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,
			 __FUNCTION__);
		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, 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,
				 __FUNCTION__, 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 */
	if (uevent_sock) {
		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;
			netlink_broadcast(uevent_sock, skb, 0, 1, GFP_KERNEL);
		}
	}
#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;

		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)) {
		printk(KERN_ERR "add_uevent_var: too many keys\n");
		WARN_ON(1);
		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)) {
		printk(KERN_ERR "add_uevent_var: buffer size too small\n");
		WARN_ON(1);
		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 __init kobject_uevent_init(void)
{
	uevent_sock = netlink_kernel_create(&init_net, NETLINK_KOBJECT_UEVENT,
					    1, NULL, NULL, THIS_MODULE);
	if (!uevent_sock) {
		printk(KERN_ERR
		       "kobject_uevent: unable to create netlink socket!\n");
		return -ENODEV;
	}

	return 0;
}

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 <[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>
1da177e4 LT	22	#include <linux/kobject.h>
	23	#include <net/sock.h>
	24
1da177e4	25
cd030c4c	26	u64 uevent_seqnum;
6a8d8abb	27	char uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH;
cd030c4c CH	28	static DEFINE_SPINLOCK(sequence_lock);
	29	#if defined(CONFIG_NET)
	30	static struct sock *uevent_sock;
	31	#endif
	32
5c5daf65 KS	33	/* the strings here must match the enum in include/linux/kobject.h */
	34	static const char *kobject_actions[] = {
	35	[KOBJ_ADD] = "add",
	36	[KOBJ_REMOVE] = "remove",
	37	[KOBJ_CHANGE] = "change",
	38	[KOBJ_MOVE] = "move",
	39	[KOBJ_ONLINE] = "online",
	40	[KOBJ_OFFLINE] = "offline",
	41	};
	42
	43	/**
	44	* kobject_action_type - translate action string to numeric type
	45	*
	46	* @buf: buffer containing the action string, newline is ignored
	47	* @len: length of buffer
	48	* @type: pointer to the location to store the action type
	49	*
	50	* Returns 0 if the action string was recognized.
	51	*/
	52	int kobject_action_type(const char *buf, size_t count,
	53	enum kobject_action *type)
	54	{
	55	enum kobject_action action;
	56	int ret = -EINVAL;
	57
	58	if (count && buf[count-1] == '\n')
	59	count--;
	60
	61	if (!count)
	62	goto out;
	63
	64	for (action = 0; action < ARRAY_SIZE(kobject_actions); action++) {
	65	if (strncmp(kobject_actions[action], buf, count) != 0)
	66	continue;
	67	if (kobject_actions[action][count] != '\0')
	68	continue;
	69	*type = action;
	70	ret = 0;
	71	break;
	72	}
	73	out:
	74	return ret;
	75	}
	76
1da177e4	77	/**
8a82472f	78	* kobject_uevent_env - send an uevent with environmental data
1da177e4	79	*
ccd490a3	80	* @action: action that is happening
1da177e4	81	* @kobj: struct kobject that the action is happening to
8a82472f	82	* @envp_ext: pointer to environmental data
542cfce6 AK	83	*
	84	* Returns 0 if kobject_uevent() is completed with success or the
	85	* corresponding error when it fails.
1da177e4	86	*/
542cfce6	87	int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
7eff2e7a	88	char *envp_ext[])
1da177e4	89	{
7eff2e7a KS	90	struct kobj_uevent_env *env;
7eff2e7a KS	91	const char *action_string = kobject_actions[action];
5f123fbd KS	92	const char *devpath = NULL;
	93	const char *subsystem;
	94	struct kobject *top_kobj;
	95	struct kset *kset;
312c004d	96	struct kset_uevent_ops *uevent_ops;
5f123fbd	97	u64 seq;
1da177e4	98	int i = 0;
542cfce6	99	int retval = 0;
1da177e4	100
9f66fa2a GKH	101	pr_debug("kobject: '%s' (%p): %s\n",
9f66fa2a GKH	102	kobject_name(kobj), kobj, __FUNCTION__);
5f123fbd	103
5f123fbd KS	104	/* search the kset we belong to */
5f123fbd KS	105	top_kobj = kobj;
ccd490a3	106	while (!top_kobj->kset && top_kobj->parent)
14193fb9	107	top_kobj = top_kobj->parent;
ccd490a3	108
542cfce6	109	if (!top_kobj->kset) {
9f66fa2a GKH	110	pr_debug("kobject: '%s' (%p): %s: attempted to send uevent "
	111	"without kset!\n", kobject_name(kobj), kobj,
	112	__FUNCTION__);
542cfce6 AK	113	return -EINVAL;
542cfce6 AK	114	}
1da177e4	115
5f123fbd	116	kset = top_kobj->kset;
312c004d	117	uevent_ops = kset->uevent_ops;
1da177e4	118
7eff2e7a	119	/* skip the event, if the filter returns zero. */
312c004d	120	if (uevent_ops && uevent_ops->filter)
542cfce6	121	if (!uevent_ops->filter(kset, kobj)) {
9f66fa2a GKH	122	pr_debug("kobject: '%s' (%p): %s: filter function "
	123	"caused the event to drop!\n",
	124	kobject_name(kobj), kobj, __FUNCTION__);
542cfce6 AK	125	return 0;
542cfce6 AK	126	}
1da177e4	127
86406245 KS	128	/* originating subsystem */
	129	if (uevent_ops && uevent_ops->name)
	130	subsystem = uevent_ops->name(kset, kobj);
	131	else
	132	subsystem = kobject_name(&kset->kobj);
	133	if (!subsystem) {
9f66fa2a GKH	134	pr_debug("kobject: '%s' (%p): %s: unset subsystem caused the "
	135	"event to drop!\n", kobject_name(kobj), kobj,
	136	__FUNCTION__);
86406245 KS	137	return 0;
	138	}
	139
7eff2e7a KS	140	/* environment buffer */
	141	env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
	142	if (!env)
542cfce6	143	return -ENOMEM;
1da177e4	144
5f123fbd KS	145	/* complete object path */
5f123fbd KS	146	devpath = kobject_get_path(kobj, GFP_KERNEL);
542cfce6 AK	147	if (!devpath) {
542cfce6 AK	148	retval = -ENOENT;
5f123fbd	149	goto exit;
542cfce6	150	}
1da177e4	151
5f123fbd	152	/* default keys */
7eff2e7a KS	153	retval = add_uevent_var(env, "ACTION=%s", action_string);
	154	if (retval)
	155	goto exit;
	156	retval = add_uevent_var(env, "DEVPATH=%s", devpath);
	157	if (retval)
	158	goto exit;
	159	retval = add_uevent_var(env, "SUBSYSTEM=%s", subsystem);
	160	if (retval)
	161	goto exit;
	162
	163	/* keys passed in from the caller */
	164	if (envp_ext) {
	165	for (i = 0; envp_ext[i]; i++) {
	166	retval = add_uevent_var(env, envp_ext[i]);
	167	if (retval)
	168	goto exit;
	169	}
	170	}
1da177e4	171
5f123fbd	172	/* let the kset specific function add its stuff */
312c004d	173	if (uevent_ops && uevent_ops->uevent) {
7eff2e7a	174	retval = uevent_ops->uevent(kset, kobj, env);
1da177e4	175	if (retval) {
9f66fa2a GKH	176	pr_debug("kobject: '%s' (%p): %s: uevent() returned "
	177	"%d\n", kobject_name(kobj), kobj,
	178	__FUNCTION__, retval);
1da177e4 LT	179	goto exit;
	180	}
	181	}
	182
0f4dafc0 KS	183	/*
	184	* Mark "add" and "remove" events in the object to ensure proper
	185	* events to userspace during automatic cleanup. If the object did
	186	* send an "add" event, "remove" will automatically generated by
	187	* the core, if not already done by the caller.
	188	*/
	189	if (action == KOBJ_ADD)
	190	kobj->state_add_uevent_sent = 1;
	191	else if (action == KOBJ_REMOVE)
	192	kobj->state_remove_uevent_sent = 1;
	193
7eff2e7a	194	/* we will send an event, so request a new sequence number */
1da177e4	195	spin_lock(&sequence_lock);
312c004d	196	seq = ++uevent_seqnum;
1da177e4	197	spin_unlock(&sequence_lock);
7eff2e7a KS	198	retval = add_uevent_var(env, "SEQNUM=%llu", (unsigned long long)seq);
	199	if (retval)
	200	goto exit;
1da177e4	201
4d17ffda	202	#if defined(CONFIG_NET)
5f123fbd KS	203	/* send netlink message */
	204	if (uevent_sock) {
	205	struct sk_buff *skb;
	206	size_t len;
	207
	208	/* allocate message with the maximum possible size */
	209	len = strlen(action_string) + strlen(devpath) + 2;
7eff2e7a	210	skb = alloc_skb(len + env->buflen, GFP_KERNEL);
5f123fbd	211	if (skb) {
7eff2e7a KS	212	char *scratch;
7eff2e7a KS	213
5f123fbd KS	214	/* add header */
	215	scratch = skb_put(skb, len);
	216	sprintf(scratch, "%s@%s", action_string, devpath);
	217
	218	/* copy keys to our continuous event payload buffer */
7eff2e7a KS	219	for (i = 0; i < env->envp_idx; i++) {
7eff2e7a KS	220	len = strlen(env->envp[i]) + 1;
5f123fbd	221	scratch = skb_put(skb, len);
7eff2e7a	222	strcpy(scratch, env->envp[i]);
5f123fbd KS	223	}
	224
	225	NETLINK_CB(skb).dst_group = 1;
	226	netlink_broadcast(uevent_sock, skb, 0, 1, GFP_KERNEL);
	227	}
	228	}
4d17ffda	229	#endif
1da177e4	230
5f123fbd	231	/* call uevent_helper, usually only enabled during early boot */
312c004d	232	if (uevent_helper[0]) {
5f123fbd	233	char *argv [3];
1da177e4	234
312c004d	235	argv [0] = uevent_helper;
5f123fbd KS	236	argv [1] = (char *)subsystem;
5f123fbd KS	237	argv [2] = NULL;
7eff2e7a KS	238	retval = add_uevent_var(env, "HOME=/");
	239	if (retval)
	240	goto exit;
e374a2bf GKH	241	retval = add_uevent_var(env,
e374a2bf GKH	242	"PATH=/sbin:/bin:/usr/sbin:/usr/bin");
7eff2e7a KS	243	if (retval)
	244	goto exit;
	245
e374a2bf	246	call_usermodehelper(argv[0], argv, env->envp, UMH_WAIT_EXEC);
5f123fbd	247	}
1da177e4 LT	248
1da177e4 LT	249	exit:
5f123fbd	250	kfree(devpath);
7eff2e7a	251	kfree(env);
542cfce6	252	return retval;
1da177e4	253	}
8a82472f CH	254	EXPORT_SYMBOL_GPL(kobject_uevent_env);
	255
	256	/**
	257	* kobject_uevent - notify userspace by ending an uevent
	258	*
ccd490a3	259	* @action: action that is happening
8a82472f	260	* @kobj: struct kobject that the action is happening to
542cfce6 AK	261	*
	262	* Returns 0 if kobject_uevent() is completed with success or the
	263	* corresponding error when it fails.
8a82472f	264	*/
542cfce6	265	int kobject_uevent(struct kobject *kobj, enum kobject_action action)
8a82472f	266	{
542cfce6	267	return kobject_uevent_env(kobj, action, NULL);
8a82472f	268	}
312c004d	269	EXPORT_SYMBOL_GPL(kobject_uevent);
1da177e4 LT	270
1da177e4 LT	271	/**
7eff2e7a KS	272	* add_uevent_var - add key value string to the environment buffer
	273	* @env: environment buffer structure
	274	* @format: printf format for the key=value pair
1da177e4 LT	275	*
	276	* Returns 0 if environment variable was added successfully or -ENOMEM
	277	* if no space was available.
	278	*/
7eff2e7a	279	int add_uevent_var(struct kobj_uevent_env env, const char format, ...)
1da177e4 LT	280	{
1da177e4 LT	281	va_list args;
7eff2e7a	282	int len;
1da177e4	283
7eff2e7a KS	284	if (env->envp_idx >= ARRAY_SIZE(env->envp)) {
	285	printk(KERN_ERR "add_uevent_var: too many keys\n");
	286	WARN_ON(1);
1da177e4	287	return -ENOMEM;
7eff2e7a	288	}
1da177e4 LT	289
1da177e4 LT	290	va_start(args, format);
7eff2e7a KS	291	len = vsnprintf(&env->buf[env->buflen],
	292	sizeof(env->buf) - env->buflen,
	293	format, args);
1da177e4 LT	294	va_end(args);
1da177e4 LT	295
7eff2e7a KS	296	if (len >= (sizeof(env->buf) - env->buflen)) {
	297	printk(KERN_ERR "add_uevent_var: buffer size too small\n");
	298	WARN_ON(1);
1da177e4	299	return -ENOMEM;
7eff2e7a	300	}
1da177e4	301
7eff2e7a KS	302	env->envp[env->envp_idx++] = &env->buf[env->buflen];
7eff2e7a KS	303	env->buflen += len + 1;
1da177e4 LT	304	return 0;
1da177e4 LT	305	}
312c004d	306	EXPORT_SYMBOL_GPL(add_uevent_var);
1da177e4	307
4d17ffda	308	#if defined(CONFIG_NET)
5f123fbd KS	309	static int __init kobject_uevent_init(void)
5f123fbd KS	310	{
b4b51029 EB	311	uevent_sock = netlink_kernel_create(&init_net, NETLINK_KOBJECT_UEVENT,
b4b51029 EB	312	1, NULL, NULL, THIS_MODULE);
5f123fbd KS	313	if (!uevent_sock) {
	314	printk(KERN_ERR
	315	"kobject_uevent: unable to create netlink socket!\n");
	316	return -ENODEV;
	317	}
	318
	319	return 0;
	320	}
	321
	322	postcore_initcall(kobject_uevent_init);
4d17ffda	323	#endif