[people/arne_f/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/export.h>
#include <linux/kmod.h>
#include <linux/slab.h>
#include <linux/socket.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <linux/uuid.h>
#include <linux/ctype.h>
#include <net/sock.h>
#include <net/net_namespace.h>


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

/* This lock protects uevent_seqnum and uevent_sock_list */
static DEFINE_MUTEX(uevent_sock_mutex);

/* 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",
	[KOBJ_BIND] =		"bind",
	[KOBJ_UNBIND] =		"unbind",
};

static int kobject_action_type(const char *buf, size_t count,
			       enum kobject_action *type,
			       const char **args)
{
	enum kobject_action action;
	size_t count_first;
	const char *args_start;
	int ret = -EINVAL;

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

	if (!count)
		goto out;

	args_start = strnchr(buf, count, ' ');
	if (args_start) {
		count_first = args_start - buf;
		args_start = args_start + 1;
	} else
		count_first = count;

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

static const char *action_arg_word_end(const char *buf, const char *buf_end,
				       char delim)
{
	const char *next = buf;

	while (next <= buf_end && *next != delim)
		if (!isalnum(*next++))
			return NULL;

	if (next == buf)
		return NULL;

	return next;
}

static int kobject_action_args(const char *buf, size_t count,
			       struct kobj_uevent_env **ret_env)
{
	struct kobj_uevent_env *env = NULL;
	const char *next, *buf_end, *key;
	int key_len;
	int r = -EINVAL;

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

	if (!count)
		return -EINVAL;

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

	/* first arg is UUID */
	if (count < UUID_STRING_LEN || !uuid_is_valid(buf) ||
	    add_uevent_var(env, "SYNTH_UUID=%.*s", UUID_STRING_LEN, buf))
		goto out;

	/*
	 * the rest are custom environment variables in KEY=VALUE
	 * format with ' ' delimiter between each KEY=VALUE pair
	 */
	next = buf + UUID_STRING_LEN;
	buf_end = buf + count - 1;

	while (next <= buf_end) {
		if (*next != ' ')
			goto out;

		/* skip the ' ', key must follow */
		key = ++next;
		if (key > buf_end)
			goto out;

		buf = next;
		next = action_arg_word_end(buf, buf_end, '=');
		if (!next || next > buf_end || *next != '=')
			goto out;
		key_len = next - buf;

		/* skip the '=', value must follow */
		if (++next > buf_end)
			goto out;

		buf = next;
		next = action_arg_word_end(buf, buf_end, ' ');
		if (!next)
			goto out;

		if (add_uevent_var(env, "SYNTH_ARG_%.*s=%.*s",
				   key_len, key, (int) (next - buf), buf))
			goto out;
	}

	r = 0;
out:
	if (r)
		kfree(env);
	else
		*ret_env = env;
	return r;
}

/**
 * kobject_synth_uevent - send synthetic uevent with arguments
 *
 * @kobj: struct kobject for which synthetic uevent is to be generated
 * @buf: buffer containing action type and action args, newline is ignored
 * @count: length of buffer
 *
 * Returns 0 if kobject_synthetic_uevent() is completed with success or the
 * corresponding error when it fails.
 */
int kobject_synth_uevent(struct kobject *kobj, const char *buf, size_t count)
{
	char *no_uuid_envp[] = { "SYNTH_UUID=0", NULL };
	enum kobject_action action;
	const char *action_args;
	struct kobj_uevent_env *env;
	const char *msg = NULL, *devpath;
	int r;

	r = kobject_action_type(buf, count, &action, &action_args);
	if (r) {
		msg = "unknown uevent action string\n";
		goto out;
	}

	if (!action_args) {
		r = kobject_uevent_env(kobj, action, no_uuid_envp);
		goto out;
	}

	r = kobject_action_args(action_args,
				count - (action_args - buf), &env);
	if (r == -EINVAL) {
		msg = "incorrect uevent action arguments\n";
		goto out;
	}

	if (r)
		goto out;

	r = kobject_uevent_env(kobj, action, env->envp);
	kfree(env);
out:
	if (r) {
		devpath = kobject_get_path(kobj, GFP_KERNEL);
		printk(KERN_WARNING "synth uevent: %s: %s",
		       devpath ?: "unknown device",
		       msg ?: "failed to send uevent");
		kfree(devpath);
	}
	return r;
}

#ifdef CONFIG_NET
static int kobj_bcast_filter(struct sock *dsk, struct sk_buff *skb, void *data)
{
	struct kobject *kobj = data, *ksobj;
	const struct kobj_ns_type_operations *ops;

	ops = kobj_ns_ops(kobj);
	if (!ops && kobj->kset) {
		ksobj = &kobj->kset->kobj;
		if (ksobj->parent != NULL)
			ops = kobj_ns_ops(ksobj->parent);
	}

	if (ops && ops->netlink_ns && kobj->ktype->namespace) {
		const void *sock_ns, *ns;
		ns = kobj->ktype->namespace(kobj);
		sock_ns = ops->netlink_ns(dsk);
		return sock_ns != ns;
	}

	return 0;
}
#endif

#ifdef CONFIG_UEVENT_HELPER
static int kobj_usermode_filter(struct kobject *kobj)
{
	const struct kobj_ns_type_operations *ops;

	ops = kobj_ns_ops(kobj);
	if (ops) {
		const void *init_ns, *ns;
		ns = kobj->ktype->namespace(kobj);
		init_ns = ops->initial_ns();
		return ns != init_ns;
	}

	return 0;
}

static int init_uevent_argv(struct kobj_uevent_env *env, const char *subsystem)
{
	int len;

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

	env->argv[0] = uevent_helper;
	env->argv[1] = &env->buf[env->buflen];
	env->argv[2] = NULL;

	env->buflen += len + 1;
	return 0;
}

static void cleanup_uevent_env(struct subprocess_info *info)
{
	kfree(info->data);
}
#endif

static void zap_modalias_env(struct kobj_uevent_env *env)
{
	static const char modalias_prefix[] = "MODALIAS=";
	int i;

	for (i = 0; i < env->envp_idx;) {
		if (strncmp(env->envp[i], modalias_prefix,
			    sizeof(modalias_prefix) - 1)) {
			i++;
			continue;
		}

		if (i != env->envp_idx - 1)
			memmove(&env->envp[i], &env->envp[i + 1],
				sizeof(env->envp[i]) * env->envp_idx - 1);

		env->envp_idx--;
	}
}

/**
 * kobject_uevent_env - send an uevent with environmental data
 *
 * @kobj: struct kobject that the action is happening to
 * @action: action that is happening
 * @envp_ext: pointer to environmental data
 *
 * Returns 0 if kobject_uevent_env() 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;
	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;
		}
	}

	switch (action) {
	case KOBJ_ADD:
		/*
		 * Mark "add" event so we can make sure we deliver "remove"
		 * event 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.
		 */
		kobj->state_add_uevent_sent = 1;
		break;

	case KOBJ_REMOVE:
		kobj->state_remove_uevent_sent = 1;
		break;

	case KOBJ_UNBIND:
		zap_modalias_env(env);
		break;

	default:
		break;
	}

	mutex_lock(&uevent_sock_mutex);
	/* we will send an event, so request a new sequence number */
	retval = add_uevent_var(env, "SEQNUM=%llu", (unsigned long long)++uevent_seqnum);
	if (retval) {
		mutex_unlock(&uevent_sock_mutex);
		goto exit;
	}

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

		if (!netlink_has_listeners(uevent_sock, 1))
			continue;

		/* 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_filtered(uevent_sock, skb,
							    0, 1, GFP_KERNEL,
							    kobj_bcast_filter,
							    kobj);
			/* ENOBUFS should be handled in userspace */
			if (retval == -ENOBUFS || retval == -ESRCH)
				retval = 0;
		} else
			retval = -ENOMEM;
	}
#endif
	mutex_unlock(&uevent_sock_mutex);

#ifdef CONFIG_UEVENT_HELPER
	/* call uevent_helper, usually only enabled during early boot */
	if (uevent_helper[0] && !kobj_usermode_filter(kobj)) {
		struct subprocess_info *info;

		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 = init_uevent_argv(env, subsystem);
		if (retval)
			goto exit;

		retval = -ENOMEM;
		info = call_usermodehelper_setup(env->argv[0], env->argv,
						 env->envp, GFP_KERNEL,
						 NULL, cleanup_uevent_env, env);
		if (info) {
			retval = call_usermodehelper_exec(info, UMH_NO_WAIT);
			env = NULL;	/* freed by cleanup_uevent_env */
		}
	}
#endif

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

/**
 * kobject_uevent - notify userspace by sending an uevent
 *
 * @kobj: struct kobject that the action is happening to
 * @action: action that is happening
 *
 * 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;
	struct netlink_kernel_cfg cfg = {
		.groups	= 1,
		.flags	= NL_CFG_F_NONROOT_RECV,
	};

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

	ue_sk->sk = netlink_kernel_create(net, NETLINK_KOBJECT_UEVENT, &cfg);
	if (!ue_sk->sk) {
		printk(KERN_ERR
		       "kobject_uevent: unable to create netlink socket!\n");
		kfree(ue_sk);
		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)
{
	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>
2d38f9a4 DL	19	#include <linux/kobject.h>
8bc3bcc9 PG	20	#include <linux/export.h>
8bc3bcc9 PG	21	#include <linux/kmod.h>
5a0e3ad6	22	#include <linux/slab.h>
1da177e4 LT	23	#include <linux/socket.h>
	24	#include <linux/skbuff.h>
	25	#include <linux/netlink.h>
f36776fa PR	26	#include <linux/uuid.h>
f36776fa PR	27	#include <linux/ctype.h>
1da177e4	28	#include <net/sock.h>
07e98962	29	#include <net/net_namespace.h>
1da177e4	30
1da177e4	31
cd030c4c	32	u64 uevent_seqnum;
86d56134	33	#ifdef CONFIG_UEVENT_HELPER
6a8d8abb	34	char uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH;
86d56134	35	#endif
07e98962 EB	36	#ifdef CONFIG_NET
	37	struct uevent_sock {
	38	struct list_head list;
	39	struct sock *sk;
	40	};
	41	static LIST_HEAD(uevent_sock_list);
cd030c4c CH	42	#endif
cd030c4c CH	43
7b60a18d AV	44	/* This lock protects uevent_seqnum and uevent_sock_list */
	45	static DEFINE_MUTEX(uevent_sock_mutex);
	46
5c5daf65 KS	47	/* the strings here must match the enum in include/linux/kobject.h */
	48	static const char *kobject_actions[] = {
	49	[KOBJ_ADD] = "add",
	50	[KOBJ_REMOVE] = "remove",
	51	[KOBJ_CHANGE] = "change",
	52	[KOBJ_MOVE] = "move",
	53	[KOBJ_ONLINE] = "online",
	54	[KOBJ_OFFLINE] = "offline",
1455cf8d DT	55	[KOBJ_BIND] = "bind",
1455cf8d DT	56	[KOBJ_UNBIND] = "unbind",
5c5daf65 KS	57	};
5c5daf65 KS	58
f36776fa PR	59	static int kobject_action_type(const char *buf, size_t count,
	60	enum kobject_action *type,
	61	const char **args)
5c5daf65 KS	62	{
5c5daf65 KS	63	enum kobject_action action;
f36776fa PR	64	size_t count_first;
f36776fa PR	65	const char *args_start;
5c5daf65 KS	66	int ret = -EINVAL;
5c5daf65 KS	67
a9edadbf	68	if (count && (buf[count-1] == '\n' \|\| buf[count-1] == '\0'))
5c5daf65 KS	69	count--;
	70
	71	if (!count)
	72	goto out;
	73
f36776fa PR	74	args_start = strnchr(buf, count, ' ');
	75	if (args_start) {
	76	count_first = args_start - buf;
	77	args_start = args_start + 1;
	78	} else
	79	count_first = count;
	80
5c5daf65	81	for (action = 0; action < ARRAY_SIZE(kobject_actions); action++) {
f36776fa	82	if (strncmp(kobject_actions[action], buf, count_first) != 0)
5c5daf65	83	continue;
f36776fa	84	if (kobject_actions[action][count_first] != '\0')
5c5daf65	85	continue;
f36776fa PR	86	if (args)
f36776fa PR	87	*args = args_start;
5c5daf65 KS	88	*type = action;
	89	ret = 0;
	90	break;
	91	}
	92	out:
	93	return ret;
	94	}
	95
f36776fa PR	96	static const char action_arg_word_end(const char buf, const char *buf_end,
	97	char delim)
	98	{
	99	const char *next = buf;
	100
	101	while (next <= buf_end && *next != delim)
	102	if (!isalnum(*next++))
	103	return NULL;
	104
	105	if (next == buf)
	106	return NULL;
	107
	108	return next;
	109	}
	110
	111	static int kobject_action_args(const char *buf, size_t count,
	112	struct kobj_uevent_env **ret_env)
	113	{
	114	struct kobj_uevent_env *env = NULL;
	115	const char next, buf_end, *key;
	116	int key_len;
	117	int r = -EINVAL;
	118
	119	if (count && (buf[count - 1] == '\n' \|\| buf[count - 1] == '\0'))
	120	count--;
	121
	122	if (!count)
	123	return -EINVAL;
	124
	125	env = kzalloc(sizeof(*env), GFP_KERNEL);
	126	if (!env)
	127	return -ENOMEM;
	128
	129	/* first arg is UUID */
	130	if (count < UUID_STRING_LEN \|\| !uuid_is_valid(buf) \|\|
	131	add_uevent_var(env, "SYNTH_UUID=%.*s", UUID_STRING_LEN, buf))
	132	goto out;
	133
	134	/*
	135	* the rest are custom environment variables in KEY=VALUE
	136	* format with ' ' delimiter between each KEY=VALUE pair
	137	*/
	138	next = buf + UUID_STRING_LEN;
	139	buf_end = buf + count - 1;
	140
	141	while (next <= buf_end) {
	142	if (*next != ' ')
	143	goto out;
	144
	145	/* skip the ' ', key must follow */
	146	key = ++next;
	147	if (key > buf_end)
	148	goto out;
	149
	150	buf = next;
	151	next = action_arg_word_end(buf, buf_end, '=');
	152	if (!next \|\| next > buf_end \|\| *next != '=')
	153	goto out;
	154	key_len = next - buf;
	155
	156	/* skip the '=', value must follow */
	157	if (++next > buf_end)
	158	goto out;
	159
160	buf = next;
161	next = action_arg_word_end(buf, buf_end, ' ');
162	if (!next)
163	goto out;
164
165	if (add_uevent_var(env, "SYNTH_ARG_%.s=%.s",
166	key_len, key, (int) (next - buf), buf))
167	goto out;
168	}
169
170	r = 0;
171	out:
172	if (r)
173	kfree(env);
174	else
175	*ret_env = env;
176	return r;
177	}
178
179	/**
180	* kobject_synth_uevent - send synthetic uevent with arguments
181	*
182	* @kobj: struct kobject for which synthetic uevent is to be generated
183	* @buf: buffer containing action type and action args, newline is ignored
184	* @count: length of buffer
185	*
186	* Returns 0 if kobject_synthetic_uevent() is completed with success or the
187	* corresponding error when it fails.
188	*/
189	int kobject_synth_uevent(struct kobject kobj, const char buf, size_t count)
190	{
191	char *no_uuid_envp[] = { "SYNTH_UUID=0", NULL };
192	enum kobject_action action;
193	const char *action_args;
194	struct kobj_uevent_env *env;
195	const char msg = NULL, devpath;
196	int r;
197
198	r = kobject_action_type(buf, count, &action, &action_args);
199	if (r) {
200	msg = "unknown uevent action string\n";
201	goto out;
202	}
203
204	if (!action_args) {
205	r = kobject_uevent_env(kobj, action, no_uuid_envp);
206	goto out;
207	}
208
209	r = kobject_action_args(action_args,
210	count - (action_args - buf), &env);
211	if (r == -EINVAL) {
212	msg = "incorrect uevent action arguments\n";
213	goto out;
214	}
215
216	if (r)
217	goto out;
218
219	r = kobject_uevent_env(kobj, action, env->envp);
220	kfree(env);
221	out:
222	if (r) {
223	devpath = kobject_get_path(kobj, GFP_KERNEL);
224	printk(KERN_WARNING "synth uevent: %s: %s",
225	devpath ?: "unknown device",
226	msg ?: "failed to send uevent");
227	kfree(devpath);
228	}
229	return r;
230	}
231
c8421286	232	#ifdef CONFIG_NET
5f71a296 EB	233	static int kobj_bcast_filter(struct sock dsk, struct sk_buff skb, void *data)
5f71a296 EB	234	{
82ef3d5d	235	struct kobject kobj = data, ksobj;
5f71a296 EB	236	const struct kobj_ns_type_operations *ops;
	237
	238	ops = kobj_ns_ops(kobj);
82ef3d5d WC	239	if (!ops && kobj->kset) {
	240	ksobj = &kobj->kset->kobj;
	241	if (ksobj->parent != NULL)
	242	ops = kobj_ns_ops(ksobj->parent);
	243	}
	244
	245	if (ops && ops->netlink_ns && kobj->ktype->namespace) {
5f71a296 EB	246	const void sock_ns, ns;
	247	ns = kobj->ktype->namespace(kobj);
	248	sock_ns = ops->netlink_ns(dsk);
	249	return sock_ns != ns;
	250	}
	251
	252	return 0;
	253	}
c8421286	254	#endif
5f71a296	255
86d56134	256	#ifdef CONFIG_UEVENT_HELPER
417daa1e EB	257	static int kobj_usermode_filter(struct kobject *kobj)
	258	{
	259	const struct kobj_ns_type_operations *ops;
	260
	261	ops = kobj_ns_ops(kobj);
	262	if (ops) {
	263	const void init_ns, ns;
	264	ns = kobj->ktype->namespace(kobj);
	265	init_ns = ops->initial_ns();
	266	return ns != init_ns;
	267	}
	268
	269	return 0;
	270	}
	271
bcccff93 VD	272	static int init_uevent_argv(struct kobj_uevent_env env, const char subsystem)
	273	{
	274	int len;
	275
	276	len = strlcpy(&env->buf[env->buflen], subsystem,
	277	sizeof(env->buf) - env->buflen);
	278	if (len >= (sizeof(env->buf) - env->buflen)) {
	279	WARN(1, KERN_ERR "init_uevent_argv: buffer size too small\n");
	280	return -ENOMEM;
	281	}
	282
	283	env->argv[0] = uevent_helper;
	284	env->argv[1] = &env->buf[env->buflen];
	285	env->argv[2] = NULL;
	286
	287	env->buflen += len + 1;
	288	return 0;
	289	}
	290
	291	static void cleanup_uevent_env(struct subprocess_info *info)
	292	{
	293	kfree(info->data);
	294	}
86d56134	295	#endif
bcccff93	296
6878e7de DT	297	static void zap_modalias_env(struct kobj_uevent_env *env)
	298	{
	299	static const char modalias_prefix[] = "MODALIAS=";
	300	int i;
	301
	302	for (i = 0; i < env->envp_idx;) {
	303	if (strncmp(env->envp[i], modalias_prefix,
	304	sizeof(modalias_prefix) - 1)) {
	305	i++;
	306	continue;
	307	}
	308
	309	if (i != env->envp_idx - 1)
	310	memmove(&env->envp[i], &env->envp[i + 1],
	311	sizeof(env->envp[i]) * env->envp_idx - 1);
	312
	313	env->envp_idx--;
	314	}
	315	}
	316
1da177e4	317	/**
8a82472f	318	* kobject_uevent_env - send an uevent with environmental data
1da177e4	319	*
1da177e4	320	* @kobj: struct kobject that the action is happening to
edbbf994	321	* @action: action that is happening
8a82472f	322	* @envp_ext: pointer to environmental data
542cfce6	323	*
f6e6e779	324	* Returns 0 if kobject_uevent_env() is completed with success or the
542cfce6	325	* corresponding error when it fails.
1da177e4	326	*/
542cfce6	327	int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
7eff2e7a	328	char *envp_ext[])
1da177e4	329	{
7eff2e7a KS	330	struct kobj_uevent_env *env;
7eff2e7a KS	331	const char *action_string = kobject_actions[action];
5f123fbd KS	332	const char *devpath = NULL;
	333	const char *subsystem;
	334	struct kobject *top_kobj;
	335	struct kset *kset;
9cd43611	336	const struct kset_uevent_ops *uevent_ops;
1da177e4	337	int i = 0;
542cfce6	338	int retval = 0;
07e98962 EB	339	#ifdef CONFIG_NET
	340	struct uevent_sock *ue_sk;
	341	#endif
1da177e4	342
9f66fa2a	343	pr_debug("kobject: '%s' (%p): %s\n",
810304db	344	kobject_name(kobj), kobj, __func__);
5f123fbd	345
5f123fbd KS	346	/* search the kset we belong to */
5f123fbd KS	347	top_kobj = kobj;
ccd490a3	348	while (!top_kobj->kset && top_kobj->parent)
14193fb9	349	top_kobj = top_kobj->parent;
ccd490a3	350
542cfce6	351	if (!top_kobj->kset) {
9f66fa2a GKH	352	pr_debug("kobject: '%s' (%p): %s: attempted to send uevent "
9f66fa2a GKH	353	"without kset!\n", kobject_name(kobj), kobj,
810304db	354	__func__);
542cfce6 AK	355	return -EINVAL;
542cfce6 AK	356	}
1da177e4	357
5f123fbd	358	kset = top_kobj->kset;
312c004d	359	uevent_ops = kset->uevent_ops;
1da177e4	360
f67f129e ML	361	/* skip the event, if uevent_suppress is set*/
	362	if (kobj->uevent_suppress) {
	363	pr_debug("kobject: '%s' (%p): %s: uevent_suppress "
	364	"caused the event to drop!\n",
	365	kobject_name(kobj), kobj, __func__);
	366	return 0;
	367	}
7eff2e7a	368	/* skip the event, if the filter returns zero. */
312c004d	369	if (uevent_ops && uevent_ops->filter)
542cfce6	370	if (!uevent_ops->filter(kset, kobj)) {
9f66fa2a GKH	371	pr_debug("kobject: '%s' (%p): %s: filter function "
9f66fa2a GKH	372	"caused the event to drop!\n",
810304db	373	kobject_name(kobj), kobj, __func__);
542cfce6 AK	374	return 0;
542cfce6 AK	375	}
1da177e4	376
86406245 KS	377	/* originating subsystem */
	378	if (uevent_ops && uevent_ops->name)
	379	subsystem = uevent_ops->name(kset, kobj);
	380	else
	381	subsystem = kobject_name(&kset->kobj);
	382	if (!subsystem) {
9f66fa2a GKH	383	pr_debug("kobject: '%s' (%p): %s: unset subsystem caused the "
9f66fa2a GKH	384	"event to drop!\n", kobject_name(kobj), kobj,
810304db	385	__func__);
86406245 KS	386	return 0;
	387	}
	388
7eff2e7a KS	389	/* environment buffer */
	390	env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
	391	if (!env)
542cfce6	392	return -ENOMEM;
1da177e4	393
5f123fbd KS	394	/* complete object path */
5f123fbd KS	395	devpath = kobject_get_path(kobj, GFP_KERNEL);
542cfce6 AK	396	if (!devpath) {
542cfce6 AK	397	retval = -ENOENT;
5f123fbd	398	goto exit;
542cfce6	399	}
1da177e4	400
5f123fbd	401	/* default keys */
7eff2e7a KS	402	retval = add_uevent_var(env, "ACTION=%s", action_string);
	403	if (retval)
	404	goto exit;
	405	retval = add_uevent_var(env, "DEVPATH=%s", devpath);
	406	if (retval)
	407	goto exit;
	408	retval = add_uevent_var(env, "SUBSYSTEM=%s", subsystem);
	409	if (retval)
	410	goto exit;
	411
	412	/* keys passed in from the caller */
	413	if (envp_ext) {
	414	for (i = 0; envp_ext[i]; i++) {
c65b9145	415	retval = add_uevent_var(env, "%s", envp_ext[i]);
7eff2e7a KS	416	if (retval)
	417	goto exit;
	418	}
	419	}
1da177e4	420
5f123fbd	421	/* let the kset specific function add its stuff */
312c004d	422	if (uevent_ops && uevent_ops->uevent) {
7eff2e7a	423	retval = uevent_ops->uevent(kset, kobj, env);
1da177e4	424	if (retval) {
9f66fa2a GKH	425	pr_debug("kobject: '%s' (%p): %s: uevent() returned "
9f66fa2a GKH	426	"%d\n", kobject_name(kobj), kobj,
810304db	427	__func__, retval);
1da177e4 LT	428	goto exit;
	429	}
	430	}
	431
6878e7de DT	432	switch (action) {
	433	case KOBJ_ADD:
	434	/*
	435	* Mark "add" event so we can make sure we deliver "remove"
	436	* event to userspace during automatic cleanup. If
	437	* the object did send an "add" event, "remove" will
	438	* automatically generated by the core, if not already done
	439	* by the caller.
	440	*/
0f4dafc0	441	kobj->state_add_uevent_sent = 1;
6878e7de DT	442	break;
	443
	444	case KOBJ_REMOVE:
0f4dafc0	445	kobj->state_remove_uevent_sent = 1;
6878e7de DT	446	break;
	447
	448	case KOBJ_UNBIND:
	449	zap_modalias_env(env);
	450	break;
	451
	452	default:
	453	break;
	454	}
0f4dafc0	455
7b60a18d	456	mutex_lock(&uevent_sock_mutex);
7eff2e7a	457	/* we will send an event, so request a new sequence number */
7b60a18d AV	458	retval = add_uevent_var(env, "SEQNUM=%llu", (unsigned long long)++uevent_seqnum);
	459	if (retval) {
	460	mutex_unlock(&uevent_sock_mutex);
7eff2e7a	461	goto exit;
7b60a18d	462	}
1da177e4	463
4d17ffda	464	#if defined(CONFIG_NET)
5f123fbd	465	/* send netlink message */
07e98962 EB	466	list_for_each_entry(ue_sk, &uevent_sock_list, list) {
07e98962 EB	467	struct sock *uevent_sock = ue_sk->sk;
5f123fbd KS	468	struct sk_buff *skb;
	469	size_t len;
	470
74099b18 KS	471	if (!netlink_has_listeners(uevent_sock, 1))
	472	continue;
	473
5f123fbd KS	474	/* allocate message with the maximum possible size */
5f123fbd KS	475	len = strlen(action_string) + strlen(devpath) + 2;
7eff2e7a	476	skb = alloc_skb(len + env->buflen, GFP_KERNEL);
5f123fbd	477	if (skb) {
7eff2e7a KS	478	char *scratch;
7eff2e7a KS	479
5f123fbd KS	480	/* add header */
	481	scratch = skb_put(skb, len);
	482	sprintf(scratch, "%s@%s", action_string, devpath);
	483
	484	/* copy keys to our continuous event payload buffer */
7eff2e7a KS	485	for (i = 0; i < env->envp_idx; i++) {
7eff2e7a KS	486	len = strlen(env->envp[i]) + 1;
5f123fbd	487	scratch = skb_put(skb, len);
7eff2e7a	488	strcpy(scratch, env->envp[i]);
5f123fbd KS	489	}
	490
	491	NETLINK_CB(skb).dst_group = 1;
5f71a296 EB	492	retval = netlink_broadcast_filtered(uevent_sock, skb,
	493	0, 1, GFP_KERNEL,
	494	kobj_bcast_filter,
	495	kobj);
ff491a73	496	/* ENOBUFS should be handled in userspace */
ebf4127c	497	if (retval == -ENOBUFS \|\| retval == -ESRCH)
ff491a73	498	retval = 0;
e0d7bf5d ML	499	} else
e0d7bf5d ML	500	retval = -ENOMEM;
5f123fbd	501	}
4d17ffda	502	#endif
7b60a18d	503	mutex_unlock(&uevent_sock_mutex);
1da177e4	504
86d56134	505	#ifdef CONFIG_UEVENT_HELPER
5f123fbd	506	/* call uevent_helper, usually only enabled during early boot */
417daa1e	507	if (uevent_helper[0] && !kobj_usermode_filter(kobj)) {
bcccff93	508	struct subprocess_info *info;
1da177e4	509
7eff2e7a KS	510	retval = add_uevent_var(env, "HOME=/");
	511	if (retval)
	512	goto exit;
e374a2bf GKH	513	retval = add_uevent_var(env,
e374a2bf GKH	514	"PATH=/sbin:/bin:/usr/sbin:/usr/bin");
7eff2e7a KS	515	if (retval)
7eff2e7a KS	516	goto exit;
bcccff93 VD	517	retval = init_uevent_argv(env, subsystem);
	518	if (retval)
	519	goto exit;
7eff2e7a	520
bcccff93 VD	521	retval = -ENOMEM;
	522	info = call_usermodehelper_setup(env->argv[0], env->argv,
	523	env->envp, GFP_KERNEL,
	524	NULL, cleanup_uevent_env, env);
	525	if (info) {
	526	retval = call_usermodehelper_exec(info, UMH_NO_WAIT);
	527	env = NULL; /* freed by cleanup_uevent_env */
	528	}
5f123fbd	529	}
86d56134	530	#endif
1da177e4 LT	531
1da177e4 LT	532	exit:
5f123fbd	533	kfree(devpath);
7eff2e7a	534	kfree(env);
542cfce6	535	return retval;
1da177e4	536	}
8a82472f CH	537	EXPORT_SYMBOL_GPL(kobject_uevent_env);
	538
	539	/**
f6e6e779	540	* kobject_uevent - notify userspace by sending an uevent
8a82472f	541	*
8a82472f	542	* @kobj: struct kobject that the action is happening to
edbbf994	543	* @action: action that is happening
542cfce6 AK	544	*
	545	* Returns 0 if kobject_uevent() is completed with success or the
	546	* corresponding error when it fails.
8a82472f	547	*/
542cfce6	548	int kobject_uevent(struct kobject *kobj, enum kobject_action action)
8a82472f	549	{
542cfce6	550	return kobject_uevent_env(kobj, action, NULL);
8a82472f	551	}
312c004d	552	EXPORT_SYMBOL_GPL(kobject_uevent);
1da177e4 LT	553
1da177e4 LT	554	/**
7eff2e7a KS	555	* add_uevent_var - add key value string to the environment buffer
	556	* @env: environment buffer structure
	557	* @format: printf format for the key=value pair
1da177e4 LT	558	*
	559	* Returns 0 if environment variable was added successfully or -ENOMEM
	560	* if no space was available.
	561	*/
7eff2e7a	562	int add_uevent_var(struct kobj_uevent_env env, const char format, ...)
1da177e4 LT	563	{
1da177e4 LT	564	va_list args;
7eff2e7a	565	int len;
1da177e4	566
7eff2e7a	567	if (env->envp_idx >= ARRAY_SIZE(env->envp)) {
5cd2b459	568	WARN(1, KERN_ERR "add_uevent_var: too many keys\n");
1da177e4	569	return -ENOMEM;
7eff2e7a	570	}
1da177e4 LT	571
1da177e4 LT	572	va_start(args, format);
7eff2e7a KS	573	len = vsnprintf(&env->buf[env->buflen],
	574	sizeof(env->buf) - env->buflen,
	575	format, args);
1da177e4 LT	576	va_end(args);
1da177e4 LT	577
7eff2e7a	578	if (len >= (sizeof(env->buf) - env->buflen)) {
5cd2b459	579	WARN(1, KERN_ERR "add_uevent_var: buffer size too small\n");
1da177e4	580	return -ENOMEM;
7eff2e7a	581	}
1da177e4	582
7eff2e7a KS	583	env->envp[env->envp_idx++] = &env->buf[env->buflen];
7eff2e7a KS	584	env->buflen += len + 1;
1da177e4 LT	585	return 0;
1da177e4 LT	586	}
312c004d	587	EXPORT_SYMBOL_GPL(add_uevent_var);
1da177e4	588
4d17ffda	589	#if defined(CONFIG_NET)
07e98962	590	static int uevent_net_init(struct net *net)
5f123fbd	591	{
07e98962	592	struct uevent_sock *ue_sk;
a31f2d17 PNA	593	struct netlink_kernel_cfg cfg = {
a31f2d17 PNA	594	.groups = 1,
9785e10a	595	.flags = NL_CFG_F_NONROOT_RECV,
a31f2d17	596	};
07e98962 EB	597
	598	ue_sk = kzalloc(sizeof(*ue_sk), GFP_KERNEL);
	599	if (!ue_sk)
	600	return -ENOMEM;
	601
9f00d977	602	ue_sk->sk = netlink_kernel_create(net, NETLINK_KOBJECT_UEVENT, &cfg);
07e98962	603	if (!ue_sk->sk) {
5f123fbd KS	604	printk(KERN_ERR
5f123fbd KS	605	"kobject_uevent: unable to create netlink socket!\n");
743db2d9	606	kfree(ue_sk);
5f123fbd KS	607	return -ENODEV;
5f123fbd KS	608	}
07e98962 EB	609	mutex_lock(&uevent_sock_mutex);
	610	list_add_tail(&ue_sk->list, &uevent_sock_list);
	611	mutex_unlock(&uevent_sock_mutex);
5f123fbd KS	612	return 0;
	613	}
	614
07e98962 EB	615	static void uevent_net_exit(struct net *net)
	616	{
	617	struct uevent_sock *ue_sk;
	618
	619	mutex_lock(&uevent_sock_mutex);
	620	list_for_each_entry(ue_sk, &uevent_sock_list, list) {
	621	if (sock_net(ue_sk->sk) == net)
	622	goto found;
	623	}
	624	mutex_unlock(&uevent_sock_mutex);
	625	return;
	626
	627	found:
	628	list_del(&ue_sk->list);
	629	mutex_unlock(&uevent_sock_mutex);
	630
	631	netlink_kernel_release(ue_sk->sk);
	632	kfree(ue_sk);
	633	}
	634
	635	static struct pernet_operations uevent_net_ops = {
	636	.init = uevent_net_init,
	637	.exit = uevent_net_exit,
	638	};
	639
	640	static int __init kobject_uevent_init(void)
	641	{
07e98962 EB	642	return register_pernet_subsys(&uevent_net_ops);
	643	}
	644
	645
5f123fbd	646	postcore_initcall(kobject_uevent_init);
4d17ffda	647	#endif