lib/kobject_uevent.c - kernel/msm-4.19 - Gitiles

 /*
  * 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/socket.h>
 #include <linux/skbuff.h>
 #include <linux/netlink.h>
 #include <linux/string.h>
 #include <linux/kobject_uevent.h>
 #include <linux/kobject.h>
 #include <net/sock.h>

 #define BUFFER_SIZE	1024	/* buffer for the hotplug env */
 #define NUM_ENVP	32	/* number of env pointers */

 #if defined(CONFIG_KOBJECT_UEVENT) || defined(CONFIG_HOTPLUG)
 static char *action_to_string(enum kobject_action action)
 {
 	switch (action) {
 	case KOBJ_ADD:
 		return "add";
 	case KOBJ_REMOVE:
 		return "remove";
 	case KOBJ_CHANGE:
 		return "change";
 	case KOBJ_MOUNT:
 		return "mount";
 	case KOBJ_UMOUNT:
 		return "umount";
 	case KOBJ_OFFLINE:
 		return "offline";
 	case KOBJ_ONLINE:
 		return "online";
 	default:
 		return NULL;
 	}
 }
 #endif

 #ifdef CONFIG_KOBJECT_UEVENT
 static struct sock *uevent_sock;

 /**
  * send_uevent - notify userspace by sending event trough netlink socket
  *
  * @signal: signal name
  * @obj: object path (kobject)
  * @envp: possible hotplug environment to pass with the message
  * @gfp_mask:
  */
 static int send_uevent(const char *signal, const char *obj,
 		       char **envp, int gfp_mask)
 {
 	struct sk_buff *skb;
 	char *pos;
 	int len;

 	if (!uevent_sock)
 		return -EIO;

 	len = strlen(signal) + 1;
 	len += strlen(obj) + 1;

 	/* allocate buffer with the maximum possible message size */
 	skb = alloc_skb(len + BUFFER_SIZE, gfp_mask);
 	if (!skb)
 		return -ENOMEM;

 	pos = skb_put(skb, len);
 	sprintf(pos, "%s@%s", signal, obj);

 	/* copy the environment key by key to our continuous buffer */
 	if (envp) {
 		int i;

 		for (i = 2; envp[i]; i++) {
 			len = strlen(envp[i]) + 1;
 			pos = skb_put(skb, len);
 			strcpy(pos, envp[i]);
 		}
 	}

 	NETLINK_CB(skb).dst_groups = 1;
 	return netlink_broadcast(uevent_sock, skb, 0, 1, gfp_mask);
 }

 static int do_kobject_uevent(struct kobject *kobj, enum kobject_action action,
 			     struct attribute *attr, int gfp_mask)
 {
 	char *path;
 	char *attrpath;
 	char *signal;
 	int len;
 	int rc = -ENOMEM;

 	path = kobject_get_path(kobj, gfp_mask);
 	if (!path)
 		return -ENOMEM;

 	signal = action_to_string(action);
 	if (!signal)
 		return -EINVAL;

 	if (attr) {
 		len = strlen(path);
 		len += strlen(attr->name) + 2;
 		attrpath = kmalloc(len, gfp_mask);
 		if (!attrpath)
 			goto exit;
 		sprintf(attrpath, "%s/%s", path, attr->name);
 		rc = send_uevent(signal, attrpath, NULL, gfp_mask);
 		kfree(attrpath);
 	} else
 		rc = send_uevent(signal, path, NULL, gfp_mask);

 exit:
 	kfree(path);
 	return rc;
 }

 /**
  * kobject_uevent - notify userspace by sending event through netlink socket
  *
  * @signal: signal name
  * @kobj: struct kobject that the event is happening to
  * @attr: optional struct attribute the event belongs to
  */
 int kobject_uevent(struct kobject *kobj, enum kobject_action action,
 		   struct attribute *attr)
 {
 	return do_kobject_uevent(kobj, action, attr, GFP_KERNEL);
 }
 EXPORT_SYMBOL_GPL(kobject_uevent);

 int kobject_uevent_atomic(struct kobject *kobj, enum kobject_action action,
 			  struct attribute *attr)
 {
 	return do_kobject_uevent(kobj, action, attr, GFP_ATOMIC);
 }
 EXPORT_SYMBOL_GPL(kobject_uevent_atomic);

 static int __init kobject_uevent_init(void)
 {
 	uevent_sock = netlink_kernel_create(NETLINK_KOBJECT_UEVENT, 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);

 #else
 static inline int send_uevent(const char *signal, const char *obj,
 			      char **envp, int gfp_mask)
 {
 	return 0;
 }

 #endif /* CONFIG_KOBJECT_UEVENT */


 #ifdef CONFIG_HOTPLUG
 char hotplug_path[HOTPLUG_PATH_LEN] = "/sbin/hotplug";
 u64 hotplug_seqnum;
 static DEFINE_SPINLOCK(sequence_lock);

 /**
  * kobject_hotplug - notify userspace by executing /sbin/hotplug
  *
  * @action: action that is happening (usually "ADD" or "REMOVE")
  * @kobj: struct kobject that the action is happening to
  */
 void kobject_hotplug(struct kobject *kobj, enum kobject_action action)
 {
 	char *argv [3];
 	char **envp = NULL;
 	char *buffer = NULL;
 	char *seq_buff;
 	char *scratch;
 	int i = 0;
 	int retval;
 	char *kobj_path = NULL;
 	const char *name = NULL;
 	char *action_string;
 	u64 seq;
 	struct kobject *top_kobj = kobj;
 	struct kset *kset;
 	static struct kset_hotplug_ops null_hotplug_ops;
 	struct kset_hotplug_ops *hotplug_ops = &null_hotplug_ops;

 	/* If this kobj does not belong to a kset,
 	   try to find a parent that does. */
 	if (!top_kobj->kset && top_kobj->parent) {
 		do {
 			top_kobj = top_kobj->parent;
 		} while (!top_kobj->kset && top_kobj->parent);
 	}

 	if (top_kobj->kset)
 		kset = top_kobj->kset;
 	else
 		return;

 	if (kset->hotplug_ops)
 		hotplug_ops = kset->hotplug_ops;

 	/* If the kset has a filter operation, call it.
 	   Skip the event, if the filter returns zero. */
 	if (hotplug_ops->filter) {
 		if (!hotplug_ops->filter(kset, kobj))
 			return;
 	}

 	pr_debug ("%s\n", __FUNCTION__);

 	action_string = action_to_string(action);
 	if (!action_string)
 		return;

 	envp = kmalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL);
 	if (!envp)
 		return;
 	memset (envp, 0x00, NUM_ENVP * sizeof (char *));

 	buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL);
 	if (!buffer)
 		goto exit;

 	if (hotplug_ops->name)
 		name = hotplug_ops->name(kset, kobj);
 	if (name == NULL)
 		name = kobject_name(&kset->kobj);

 	argv [0] = hotplug_path;
 	argv [1] = (char *)name; /* won't be changed but 'const' has to go */
 	argv [2] = NULL;

 	/* minimal command environment */
 	envp [i++] = "HOME=/";
 	envp [i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";

 	scratch = buffer;

 	envp [i++] = scratch;
 	scratch += sprintf(scratch, "ACTION=%s", action_string) + 1;

 	kobj_path = kobject_get_path(kobj, GFP_KERNEL);
 	if (!kobj_path)
 		goto exit;

 	envp [i++] = scratch;
 	scratch += sprintf (scratch, "DEVPATH=%s", kobj_path) + 1;

 	envp [i++] = scratch;
 	scratch += sprintf(scratch, "SUBSYSTEM=%s", name) + 1;

 	/* reserve space for the sequence,
 	 * put the real one in after the hotplug call */
 	envp[i++] = seq_buff = scratch;
 	scratch += strlen("SEQNUM=18446744073709551616") + 1;

 	if (hotplug_ops->hotplug) {
 		/* have the kset specific function add its stuff */
 		retval = hotplug_ops->hotplug (kset, kobj,
 				  &envp[i], NUM_ENVP - i, scratch,
 				  BUFFER_SIZE - (scratch - buffer));
 		if (retval) {
 			pr_debug ("%s - hotplug() returned %d\n",
 				  __FUNCTION__, retval);
 			goto exit;
 		}
 	}

 	spin_lock(&sequence_lock);
 	seq = ++hotplug_seqnum;
 	spin_unlock(&sequence_lock);
 	sprintf(seq_buff, "SEQNUM=%llu", (unsigned long long)seq);

 	pr_debug ("%s: %s %s seq=%llu %s %s %s %s %s\n",
 		  __FUNCTION__, argv[0], argv[1], (unsigned long long)seq,
 		  envp[0], envp[1], envp[2], envp[3], envp[4]);

 	send_uevent(action_string, kobj_path, envp, GFP_KERNEL);

 	if (!hotplug_path[0])
 		goto exit;

 	retval = call_usermodehelper (argv[0], argv, envp, 0);
 	if (retval)
 		pr_debug ("%s - call_usermodehelper returned %d\n",
 			  __FUNCTION__, retval);

 exit:
 	kfree(kobj_path);
 	kfree(buffer);
 	kfree(envp);
 	return;
 }
 EXPORT_SYMBOL(kobject_hotplug);

 /**
  * add_hotplug_env_var - helper for creating hotplug environment variables
  * @envp: Pointer to table of environment variables, as passed into
  * hotplug() method.
  * @num_envp: Number of environment variable slots available, as
  * passed into hotplug() method.
  * @cur_index: Pointer to current index into @envp.  It should be
  * initialized to 0 before the first call to add_hotplug_env_var(),
  * and will be incremented on success.
  * @buffer: Pointer to buffer for environment variables, as passed
  * into hotplug() method.
  * @buffer_size: Length of @buffer, as passed into hotplug() method.
  * @cur_len: Pointer to current length of space used in @buffer.
  * Should be initialized to 0 before the first call to
  * add_hotplug_env_var(), and will be incremented on success.
  * @format: Format for creating environment variable (of the form
  * "XXX=%x") for snprintf().
  *
  * Returns 0 if environment variable was added successfully or -ENOMEM
  * if no space was available.
  */
 int add_hotplug_env_var(char **envp, int num_envp, int *cur_index,
 			char *buffer, int buffer_size, int *cur_len,
 			const char *format, ...)
 {
 	va_list args;

 	/*
 	 * We check against num_envp - 1 to make sure there is at
 	 * least one slot left after we return, since the hotplug
 	 * method needs to set the last slot to NULL.
 	 */
 	if (*cur_index >= num_envp - 1)
 		return -ENOMEM;

 	envp[*cur_index] = buffer + *cur_len;

 	va_start(args, format);
 	*cur_len += vsnprintf(envp[*cur_index],
 			      max(buffer_size - *cur_len, 0),
 			      format, args) + 1;
 	va_end(args);

 	if (*cur_len > buffer_size)
 		return -ENOMEM;

 	(*cur_index)++;
 	return 0;
 }
 EXPORT_SYMBOL(add_hotplug_env_var);

 #endif /* CONFIG_HOTPLUG */
	/*
	* 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/socket.h>
	#include <linux/skbuff.h>
	#include <linux/netlink.h>
	#include <linux/string.h>
	#include <linux/kobject_uevent.h>
	#include <linux/kobject.h>
	#include <net/sock.h>

	#define BUFFER_SIZE 1024 /* buffer for the hotplug env */
	#define NUM_ENVP 32 /* number of env pointers */

	#if defined(CONFIG_KOBJECT_UEVENT) \|\| defined(CONFIG_HOTPLUG)
	static char *action_to_string(enum kobject_action action)
	{
	switch (action) {
	case KOBJ_ADD:
	return "add";
	case KOBJ_REMOVE:
	return "remove";
	case KOBJ_CHANGE:
	return "change";
	case KOBJ_MOUNT:
	return "mount";
	case KOBJ_UMOUNT:
	return "umount";
	case KOBJ_OFFLINE:
	return "offline";
	case KOBJ_ONLINE:
	return "online";
	default:
	return NULL;
	}
	}
	#endif

	#ifdef CONFIG_KOBJECT_UEVENT
	static struct sock *uevent_sock;

	/**
	* send_uevent - notify userspace by sending event trough netlink socket
	*
	* @signal: signal name
	* @obj: object path (kobject)
	* @envp: possible hotplug environment to pass with the message
	* @gfp_mask:
	*/
	static int send_uevent(const char signal, const char obj,
	char **envp, int gfp_mask)
	{
	struct sk_buff *skb;
	char *pos;
	int len;

	if (!uevent_sock)
	return -EIO;

	len = strlen(signal) + 1;
	len += strlen(obj) + 1;

	/* allocate buffer with the maximum possible message size */
	skb = alloc_skb(len + BUFFER_SIZE, gfp_mask);
	if (!skb)
	return -ENOMEM;

	pos = skb_put(skb, len);
	sprintf(pos, "%s@%s", signal, obj);

	/* copy the environment key by key to our continuous buffer */
	if (envp) {
	int i;

	for (i = 2; envp[i]; i++) {
	len = strlen(envp[i]) + 1;
	pos = skb_put(skb, len);
	strcpy(pos, envp[i]);
	}
	}

	NETLINK_CB(skb).dst_groups = 1;
	return netlink_broadcast(uevent_sock, skb, 0, 1, gfp_mask);
	}

	static int do_kobject_uevent(struct kobject *kobj, enum kobject_action action,
	struct attribute *attr, int gfp_mask)
	{
	char *path;
	char *attrpath;
	char *signal;
	int len;
	int rc = -ENOMEM;

	path = kobject_get_path(kobj, gfp_mask);
	if (!path)
	return -ENOMEM;

	signal = action_to_string(action);
	if (!signal)
	return -EINVAL;

	if (attr) {
	len = strlen(path);
	len += strlen(attr->name) + 2;
	attrpath = kmalloc(len, gfp_mask);
	if (!attrpath)
	goto exit;
	sprintf(attrpath, "%s/%s", path, attr->name);
	rc = send_uevent(signal, attrpath, NULL, gfp_mask);
	kfree(attrpath);
	} else
	rc = send_uevent(signal, path, NULL, gfp_mask);

	exit:
	kfree(path);
	return rc;
	}

	/**
	* kobject_uevent - notify userspace by sending event through netlink socket
	*
	* @signal: signal name
	* @kobj: struct kobject that the event is happening to
	* @attr: optional struct attribute the event belongs to
	*/
	int kobject_uevent(struct kobject *kobj, enum kobject_action action,
	struct attribute *attr)
	{
	return do_kobject_uevent(kobj, action, attr, GFP_KERNEL);
	}
	EXPORT_SYMBOL_GPL(kobject_uevent);

	int kobject_uevent_atomic(struct kobject *kobj, enum kobject_action action,
	struct attribute *attr)
	{
	return do_kobject_uevent(kobj, action, attr, GFP_ATOMIC);
	}
	EXPORT_SYMBOL_GPL(kobject_uevent_atomic);

	static int __init kobject_uevent_init(void)
	{
	uevent_sock = netlink_kernel_create(NETLINK_KOBJECT_UEVENT, 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);

	#else
	static inline int send_uevent(const char signal, const char obj,
	char **envp, int gfp_mask)
	{
	return 0;
	}

	#endif /* CONFIG_KOBJECT_UEVENT */


	#ifdef CONFIG_HOTPLUG
	char hotplug_path[HOTPLUG_PATH_LEN] = "/sbin/hotplug";
	u64 hotplug_seqnum;
	static DEFINE_SPINLOCK(sequence_lock);

	/**
	* kobject_hotplug - notify userspace by executing /sbin/hotplug
	*
	* @action: action that is happening (usually "ADD" or "REMOVE")
	* @kobj: struct kobject that the action is happening to
	*/
	void kobject_hotplug(struct kobject *kobj, enum kobject_action action)
	{
	char *argv [3];
	char **envp = NULL;
	char *buffer = NULL;
	char *seq_buff;
	char *scratch;
	int i = 0;
	int retval;
	char *kobj_path = NULL;
	const char *name = NULL;
	char *action_string;
	u64 seq;
	struct kobject *top_kobj = kobj;
	struct kset *kset;
	static struct kset_hotplug_ops null_hotplug_ops;
	struct kset_hotplug_ops *hotplug_ops = &null_hotplug_ops;

	/* If this kobj does not belong to a kset,
	try to find a parent that does. */
	if (!top_kobj->kset && top_kobj->parent) {
	do {
	top_kobj = top_kobj->parent;
	} while (!top_kobj->kset && top_kobj->parent);
	}

	if (top_kobj->kset)
	kset = top_kobj->kset;
	else
	return;

	if (kset->hotplug_ops)
	hotplug_ops = kset->hotplug_ops;

	/* If the kset has a filter operation, call it.
	Skip the event, if the filter returns zero. */
	if (hotplug_ops->filter) {
	if (!hotplug_ops->filter(kset, kobj))
	return;
	}

	pr_debug ("%s\n", __FUNCTION__);

	action_string = action_to_string(action);
	if (!action_string)
	return;

	envp = kmalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL);
	if (!envp)
	return;
	memset (envp, 0x00, NUM_ENVP * sizeof (char *));

	buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL);
	if (!buffer)
	goto exit;

	if (hotplug_ops->name)
	name = hotplug_ops->name(kset, kobj);
	if (name == NULL)
	name = kobject_name(&kset->kobj);

	argv [0] = hotplug_path;
	argv [1] = (char )name; / won't be changed but 'const' has to go */
	argv [2] = NULL;

	/* minimal command environment */
	envp [i++] = "HOME=/";
	envp [i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";

	scratch = buffer;

	envp [i++] = scratch;
	scratch += sprintf(scratch, "ACTION=%s", action_string) + 1;

	kobj_path = kobject_get_path(kobj, GFP_KERNEL);
	if (!kobj_path)
	goto exit;

	envp [i++] = scratch;
	scratch += sprintf (scratch, "DEVPATH=%s", kobj_path) + 1;

	envp [i++] = scratch;
	scratch += sprintf(scratch, "SUBSYSTEM=%s", name) + 1;

	/* reserve space for the sequence,
	* put the real one in after the hotplug call */
	envp[i++] = seq_buff = scratch;
	scratch += strlen("SEQNUM=18446744073709551616") + 1;

	if (hotplug_ops->hotplug) {
	/* have the kset specific function add its stuff */
	retval = hotplug_ops->hotplug (kset, kobj,
	&envp[i], NUM_ENVP - i, scratch,
	BUFFER_SIZE - (scratch - buffer));
	if (retval) {
	pr_debug ("%s - hotplug() returned %d\n",
	__FUNCTION__, retval);
	goto exit;
	}
	}

	spin_lock(&sequence_lock);
	seq = ++hotplug_seqnum;
	spin_unlock(&sequence_lock);
	sprintf(seq_buff, "SEQNUM=%llu", (unsigned long long)seq);

	pr_debug ("%s: %s %s seq=%llu %s %s %s %s %s\n",
	__FUNCTION__, argv[0], argv[1], (unsigned long long)seq,
	envp[0], envp[1], envp[2], envp[3], envp[4]);

	send_uevent(action_string, kobj_path, envp, GFP_KERNEL);

	if (!hotplug_path[0])
	goto exit;

	retval = call_usermodehelper (argv[0], argv, envp, 0);
	if (retval)
	pr_debug ("%s - call_usermodehelper returned %d\n",
	__FUNCTION__, retval);

	exit:
	kfree(kobj_path);
	kfree(buffer);
	kfree(envp);
	return;
	}
	EXPORT_SYMBOL(kobject_hotplug);

	/**
	* add_hotplug_env_var - helper for creating hotplug environment variables
	* @envp: Pointer to table of environment variables, as passed into
	* hotplug() method.
	* @num_envp: Number of environment variable slots available, as
	* passed into hotplug() method.
	* @cur_index: Pointer to current index into @envp. It should be
	* initialized to 0 before the first call to add_hotplug_env_var(),
	* and will be incremented on success.
	* @buffer: Pointer to buffer for environment variables, as passed
	* into hotplug() method.
	* @buffer_size: Length of @buffer, as passed into hotplug() method.
	* @cur_len: Pointer to current length of space used in @buffer.
	* Should be initialized to 0 before the first call to
	* add_hotplug_env_var(), and will be incremented on success.
	* @format: Format for creating environment variable (of the form
	* "XXX=%x") for snprintf().
	*
	* Returns 0 if environment variable was added successfully or -ENOMEM
	* if no space was available.
	*/
	int add_hotplug_env_var(char *envp, int num_envp, int cur_index,
	char buffer, int buffer_size, int cur_len,
	const char *format, ...)
	{
	va_list args;

	/*
	* We check against num_envp - 1 to make sure there is at
	* least one slot left after we return, since the hotplug
	* method needs to set the last slot to NULL.
	*/
	if (*cur_index >= num_envp - 1)
	return -ENOMEM;

	envp[cur_index] = buffer + cur_len;

	va_start(args, format);
	cur_len += vsnprintf(envp[cur_index],
	max(buffer_size - *cur_len, 0),
	format, args) + 1;
	va_end(args);

	if (*cur_len > buffer_size)
	return -ENOMEM;

	(*cur_index)++;
	return 0;
	}
	EXPORT_SYMBOL(add_hotplug_env_var);

	#endif /* CONFIG_HOTPLUG */