lib/kobject_uevent.c - maze/linux - Git at Google

 /*
  * 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/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, 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;
 			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;

 		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
	/*
	* 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/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, 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;
	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;

	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