/* * 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/user_namespace.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;#ifdef CONFIG_NETstruct 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",}; /** * 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;} #ifdef CONFIG_NETstatic int kobj_bcast_filter(struct sock *dsk, struct sk_buff *skb, void *data){	struct kobject *kobj = data;	const struct kobj_ns_type_operations *ops; 	ops = kobj_ns_ops(kobj);	if (ops) {		const void *sock_ns, *ns;		ns = kobj->ktype->namespace(kobj);		sock_ns = ops->netlink_ns(dsk);		return sock_ns != ns;	} 	return 0;}#endif 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;} /** * 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_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;		}	} 	/*	 * 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; 	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); 	/* call uevent_helper, usually only enabled during early boot */	if (uevent_helper[0] && !kobj_usermode_filter(kobj)) {		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 sending 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;	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