[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/string.h>
#include <linux/kobject.h>
#include <linux/module.h>

#include <linux/socket.h>
#include <linux/skbuff.h>
#include <linux/netlink.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' || 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;
	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, __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 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 */
	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;
			retval = netlink_broadcast(uevent_sock, skb, 0, 1,
						   GFP_KERNEL);
		} else
			retval = -ENOMEM;
	}
#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 __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>
2d38f9a4 DL	18	#include <linux/string.h>
	19	#include <linux/kobject.h>
	20	#include <linux/module.h>
	21
1da177e4 LT	22	#include <linux/socket.h>
	23	#include <linux/skbuff.h>
	24	#include <linux/netlink.h>
1da177e4 LT	25	#include <net/sock.h>
1da177e4 LT	26
1da177e4	27
cd030c4c	28	u64 uevent_seqnum;
6a8d8abb	29	char uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH;
cd030c4c CH	30	static DEFINE_SPINLOCK(sequence_lock);
	31	#if defined(CONFIG_NET)
	32	static struct sock *uevent_sock;
	33	#endif
	34
5c5daf65 KS	35	/* the strings here must match the enum in include/linux/kobject.h */
	36	static const char *kobject_actions[] = {
	37	[KOBJ_ADD] = "add",
	38	[KOBJ_REMOVE] = "remove",
	39	[KOBJ_CHANGE] = "change",
	40	[KOBJ_MOVE] = "move",
	41	[KOBJ_ONLINE] = "online",
	42	[KOBJ_OFFLINE] = "offline",
	43	};
	44
	45	/**
	46	* kobject_action_type - translate action string to numeric type
	47	*
	48	* @buf: buffer containing the action string, newline is ignored
	49	* @len: length of buffer
	50	* @type: pointer to the location to store the action type
	51	*
	52	* Returns 0 if the action string was recognized.
	53	*/
	54	int kobject_action_type(const char *buf, size_t count,
	55	enum kobject_action *type)
	56	{
	57	enum kobject_action action;
	58	int ret = -EINVAL;
	59
a9edadbf	60	if (count && (buf[count-1] == '\n' \|\| buf[count-1] == '\0'))
5c5daf65 KS	61	count--;
	62
	63	if (!count)
	64	goto out;
	65
	66	for (action = 0; action < ARRAY_SIZE(kobject_actions); action++) {
	67	if (strncmp(kobject_actions[action], buf, count) != 0)
	68	continue;
	69	if (kobject_actions[action][count] != '\0')
	70	continue;
	71	*type = action;
	72	ret = 0;
	73	break;
	74	}
	75	out:
	76	return ret;
	77	}
	78
1da177e4	79	/**
8a82472f	80	* kobject_uevent_env - send an uevent with environmental data
1da177e4	81	*
ccd490a3	82	* @action: action that is happening
1da177e4	83	* @kobj: struct kobject that the action is happening to
8a82472f	84	* @envp_ext: pointer to environmental data
542cfce6 AK	85	*
	86	* Returns 0 if kobject_uevent() is completed with success or the
	87	* corresponding error when it fails.
1da177e4	88	*/
542cfce6	89	int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
7eff2e7a	90	char *envp_ext[])
1da177e4	91	{
7eff2e7a KS	92	struct kobj_uevent_env *env;
7eff2e7a KS	93	const char *action_string = kobject_actions[action];
5f123fbd KS	94	const char *devpath = NULL;
	95	const char *subsystem;
	96	struct kobject *top_kobj;
	97	struct kset *kset;
312c004d	98	struct kset_uevent_ops *uevent_ops;
5f123fbd	99	u64 seq;
1da177e4	100	int i = 0;
542cfce6	101	int retval = 0;
1da177e4	102
9f66fa2a	103	pr_debug("kobject: '%s' (%p): %s\n",
810304db	104	kobject_name(kobj), kobj, __func__);
5f123fbd	105
5f123fbd KS	106	/* search the kset we belong to */
5f123fbd KS	107	top_kobj = kobj;
ccd490a3	108	while (!top_kobj->kset && top_kobj->parent)
14193fb9	109	top_kobj = top_kobj->parent;
ccd490a3	110
542cfce6	111	if (!top_kobj->kset) {
9f66fa2a GKH	112	pr_debug("kobject: '%s' (%p): %s: attempted to send uevent "
9f66fa2a GKH	113	"without kset!\n", kobject_name(kobj), kobj,
810304db	114	__func__);
542cfce6 AK	115	return -EINVAL;
542cfce6 AK	116	}
1da177e4	117
5f123fbd	118	kset = top_kobj->kset;
312c004d	119	uevent_ops = kset->uevent_ops;
1da177e4	120
7eff2e7a	121	/* skip the event, if the filter returns zero. */
312c004d	122	if (uevent_ops && uevent_ops->filter)
542cfce6	123	if (!uevent_ops->filter(kset, kobj)) {
9f66fa2a GKH	124	pr_debug("kobject: '%s' (%p): %s: filter function "
9f66fa2a GKH	125	"caused the event to drop!\n",
810304db	126	kobject_name(kobj), kobj, __func__);
542cfce6 AK	127	return 0;
542cfce6 AK	128	}
1da177e4	129
86406245 KS	130	/* originating subsystem */
	131	if (uevent_ops && uevent_ops->name)
	132	subsystem = uevent_ops->name(kset, kobj);
	133	else
	134	subsystem = kobject_name(&kset->kobj);
	135	if (!subsystem) {
9f66fa2a GKH	136	pr_debug("kobject: '%s' (%p): %s: unset subsystem caused the "
9f66fa2a GKH	137	"event to drop!\n", kobject_name(kobj), kobj,
810304db	138	__func__);
86406245 KS	139	return 0;
	140	}
	141
7eff2e7a KS	142	/* environment buffer */
	143	env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
	144	if (!env)
542cfce6	145	return -ENOMEM;
1da177e4	146
5f123fbd KS	147	/* complete object path */
5f123fbd KS	148	devpath = kobject_get_path(kobj, GFP_KERNEL);
542cfce6 AK	149	if (!devpath) {
542cfce6 AK	150	retval = -ENOENT;
5f123fbd	151	goto exit;
542cfce6	152	}
1da177e4	153
5f123fbd	154	/* default keys */
7eff2e7a KS	155	retval = add_uevent_var(env, "ACTION=%s", action_string);
	156	if (retval)
	157	goto exit;
	158	retval = add_uevent_var(env, "DEVPATH=%s", devpath);
	159	if (retval)
	160	goto exit;
	161	retval = add_uevent_var(env, "SUBSYSTEM=%s", subsystem);
	162	if (retval)
	163	goto exit;
	164
	165	/* keys passed in from the caller */
	166	if (envp_ext) {
	167	for (i = 0; envp_ext[i]; i++) {
c65b9145	168	retval = add_uevent_var(env, "%s", envp_ext[i]);
7eff2e7a KS	169	if (retval)
	170	goto exit;
	171	}
	172	}
1da177e4	173
5f123fbd	174	/* let the kset specific function add its stuff */
312c004d	175	if (uevent_ops && uevent_ops->uevent) {
7eff2e7a	176	retval = uevent_ops->uevent(kset, kobj, env);
1da177e4	177	if (retval) {
9f66fa2a GKH	178	pr_debug("kobject: '%s' (%p): %s: uevent() returned "
9f66fa2a GKH	179	"%d\n", kobject_name(kobj), kobj,
810304db	180	__func__, retval);
1da177e4 LT	181	goto exit;
	182	}
	183	}
	184
0f4dafc0 KS	185	/*
	186	* Mark "add" and "remove" events in the object to ensure proper
	187	* events to userspace during automatic cleanup. If the object did
	188	* send an "add" event, "remove" will automatically generated by
	189	* the core, if not already done by the caller.
	190	*/
	191	if (action == KOBJ_ADD)
	192	kobj->state_add_uevent_sent = 1;
	193	else if (action == KOBJ_REMOVE)
	194	kobj->state_remove_uevent_sent = 1;
	195
7eff2e7a	196	/* we will send an event, so request a new sequence number */
1da177e4	197	spin_lock(&sequence_lock);
312c004d	198	seq = ++uevent_seqnum;
1da177e4	199	spin_unlock(&sequence_lock);
7eff2e7a KS	200	retval = add_uevent_var(env, "SEQNUM=%llu", (unsigned long long)seq);
	201	if (retval)
	202	goto exit;
1da177e4	203
4d17ffda	204	#if defined(CONFIG_NET)
5f123fbd KS	205	/* send netlink message */
	206	if (uevent_sock) {
	207	struct sk_buff *skb;
	208	size_t len;
	209
	210	/* allocate message with the maximum possible size */
	211	len = strlen(action_string) + strlen(devpath) + 2;
7eff2e7a	212	skb = alloc_skb(len + env->buflen, GFP_KERNEL);
5f123fbd	213	if (skb) {
7eff2e7a KS	214	char *scratch;
7eff2e7a KS	215
5f123fbd KS	216	/* add header */
	217	scratch = skb_put(skb, len);
	218	sprintf(scratch, "%s@%s", action_string, devpath);
	219
	220	/* copy keys to our continuous event payload buffer */
7eff2e7a KS	221	for (i = 0; i < env->envp_idx; i++) {
7eff2e7a KS	222	len = strlen(env->envp[i]) + 1;
5f123fbd	223	scratch = skb_put(skb, len);
7eff2e7a	224	strcpy(scratch, env->envp[i]);
5f123fbd KS	225	}
	226
	227	NETLINK_CB(skb).dst_group = 1;
e0d7bf5d ML	228	retval = netlink_broadcast(uevent_sock, skb, 0, 1,
	229	GFP_KERNEL);
	230	} else
	231	retval = -ENOMEM;
5f123fbd	232	}
4d17ffda	233	#endif
1da177e4	234
5f123fbd	235	/* call uevent_helper, usually only enabled during early boot */
312c004d	236	if (uevent_helper[0]) {
5f123fbd	237	char *argv [3];
1da177e4	238
312c004d	239	argv [0] = uevent_helper;
5f123fbd KS	240	argv [1] = (char *)subsystem;
5f123fbd KS	241	argv [2] = NULL;
7eff2e7a KS	242	retval = add_uevent_var(env, "HOME=/");
	243	if (retval)
	244	goto exit;
e374a2bf GKH	245	retval = add_uevent_var(env,
e374a2bf GKH	246	"PATH=/sbin:/bin:/usr/sbin:/usr/bin");
7eff2e7a KS	247	if (retval)
	248	goto exit;
	249
0ad1d6f3 WC	250	retval = call_usermodehelper(argv[0], argv,
0ad1d6f3 WC	251	env->envp, UMH_WAIT_EXEC);
5f123fbd	252	}
1da177e4 LT	253
1da177e4 LT	254	exit:
5f123fbd	255	kfree(devpath);
7eff2e7a	256	kfree(env);
542cfce6	257	return retval;
1da177e4	258	}
8a82472f CH	259	EXPORT_SYMBOL_GPL(kobject_uevent_env);
	260
	261	/**
	262	* kobject_uevent - notify userspace by ending an uevent
	263	*
ccd490a3	264	* @action: action that is happening
8a82472f	265	* @kobj: struct kobject that the action is happening to
542cfce6 AK	266	*
	267	* Returns 0 if kobject_uevent() is completed with success or the
	268	* corresponding error when it fails.
8a82472f	269	*/
542cfce6	270	int kobject_uevent(struct kobject *kobj, enum kobject_action action)
8a82472f	271	{
542cfce6	272	return kobject_uevent_env(kobj, action, NULL);
8a82472f	273	}
312c004d	274	EXPORT_SYMBOL_GPL(kobject_uevent);
1da177e4 LT	275
1da177e4 LT	276	/**
7eff2e7a KS	277	* add_uevent_var - add key value string to the environment buffer
	278	* @env: environment buffer structure
	279	* @format: printf format for the key=value pair
1da177e4 LT	280	*
	281	* Returns 0 if environment variable was added successfully or -ENOMEM
	282	* if no space was available.
	283	*/
7eff2e7a	284	int add_uevent_var(struct kobj_uevent_env env, const char format, ...)
1da177e4 LT	285	{
1da177e4 LT	286	va_list args;
7eff2e7a	287	int len;
1da177e4	288
7eff2e7a	289	if (env->envp_idx >= ARRAY_SIZE(env->envp)) {
5cd2b459	290	WARN(1, KERN_ERR "add_uevent_var: too many keys\n");
1da177e4	291	return -ENOMEM;
7eff2e7a	292	}
1da177e4 LT	293
1da177e4 LT	294	va_start(args, format);
7eff2e7a KS	295	len = vsnprintf(&env->buf[env->buflen],
	296	sizeof(env->buf) - env->buflen,
	297	format, args);
1da177e4 LT	298	va_end(args);
1da177e4 LT	299
7eff2e7a	300	if (len >= (sizeof(env->buf) - env->buflen)) {
5cd2b459	301	WARN(1, KERN_ERR "add_uevent_var: buffer size too small\n");
1da177e4	302	return -ENOMEM;
7eff2e7a	303	}
1da177e4	304
7eff2e7a KS	305	env->envp[env->envp_idx++] = &env->buf[env->buflen];
7eff2e7a KS	306	env->buflen += len + 1;
1da177e4 LT	307	return 0;
1da177e4 LT	308	}
312c004d	309	EXPORT_SYMBOL_GPL(add_uevent_var);
1da177e4	310
4d17ffda	311	#if defined(CONFIG_NET)
5f123fbd KS	312	static int __init kobject_uevent_init(void)
5f123fbd KS	313	{
b4b51029 EB	314	uevent_sock = netlink_kernel_create(&init_net, NETLINK_KOBJECT_UEVENT,
b4b51029 EB	315	1, NULL, NULL, THIS_MODULE);
5f123fbd KS	316	if (!uevent_sock) {
	317	printk(KERN_ERR
	318	"kobject_uevent: unable to create netlink socket!\n");
	319	return -ENODEV;
	320	}
	321
	322	return 0;
	323	}
	324
	325	postcore_initcall(kobject_uevent_init);
4d17ffda	326	#endif