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/* * 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_HELPERchar uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH;#endif#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",}; 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_NETstatic 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_HELPERstatic 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 /** * 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;		}	} 	/*	 * 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); #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;

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