[mirror_ubuntu-artful-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/socket.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <linux/string.h>
#include <linux/kobject.h>
#include <net/sock.h>

#define BUFFER_SIZE	2048	/* buffer for the variables */
#define NUM_ENVP	32	/* number of env pointers */

#if defined(CONFIG_HOTPLUG) && defined(CONFIG_NET)
u64 uevent_seqnum;
char uevent_helper[UEVENT_HELPER_PATH_LEN] = "/sbin/hotplug";
static DEFINE_SPINLOCK(sequence_lock);
static struct sock *uevent_sock;

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;
	}
}

/**
 * kobject_uevent - notify userspace by ending an uevent
 *
 * @action: action that is happening (usually KOBJ_ADD and KOBJ_REMOVE)
 * @kobj: struct kobject that the action is happening to
 */
void kobject_uevent(struct kobject *kobj, enum kobject_action action)
{
	char **envp;
	char *buffer;
	char *scratch;
	const char *action_string;
	const char *devpath = NULL;
	const char *subsystem;
	struct kobject *top_kobj;
	struct kset *kset;
	struct kset_uevent_ops *uevent_ops;
	u64 seq;
	char *seq_buff;
	int i = 0;
	int retval;

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

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

	/* search the kset we belong to */
	top_kobj = kobj;
	if (!top_kobj->kset && top_kobj->parent) {
		do {
			top_kobj = top_kobj->parent;
		} while (!top_kobj->kset && top_kobj->parent);
	}
	if (!top_kobj->kset)
		return;

	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))
			return;

	/* environment index */
	envp = kzalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL);
	if (!envp)
		return;

	/* environment values */
	buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL);
	if (!buffer)
		goto exit;

	/* complete object path */
	devpath = kobject_get_path(kobj, GFP_KERNEL);
	if (!devpath)
		goto exit;

	/* originating subsystem */
	if (uevent_ops && uevent_ops->name)
		subsystem = uevent_ops->name(kset, kobj);
	else
		subsystem = kobject_name(&kset->kobj);

	/* event environemnt for helper process only */
	envp[i++] = "HOME=/";
	envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";

	/* default keys */
	scratch = buffer;
	envp [i++] = scratch;
	scratch += sprintf(scratch, "ACTION=%s", action_string) + 1;
	envp [i++] = scratch;
	scratch += sprintf (scratch, "DEVPATH=%s", devpath) + 1;
	envp [i++] = scratch;
	scratch += sprintf(scratch, "SUBSYSTEM=%s", subsystem) + 1;

	/* just reserve the space, overwrite it after kset call has returned */
	envp[i++] = seq_buff = scratch;
	scratch += strlen("SEQNUM=18446744073709551616") + 1;

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

	/* we will send an event, request a new sequence number */
	spin_lock(&sequence_lock);
	seq = ++uevent_seqnum;
	spin_unlock(&sequence_lock);
	sprintf(seq_buff, "SEQNUM=%llu", (unsigned long long)seq);

	/* 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 + BUFFER_SIZE, GFP_KERNEL);
		if (skb) {
			/* add header */
			scratch = skb_put(skb, len);
			sprintf(scratch, "%s@%s", action_string, devpath);

			/* copy keys to our continuous event payload buffer */
			for (i = 2; envp[i]; i++) {
				len = strlen(envp[i]) + 1;
				scratch = skb_put(skb, len);
				strcpy(scratch, envp[i]);
			}

			NETLINK_CB(skb).dst_group = 1;
			netlink_broadcast(uevent_sock, skb, 0, 1, GFP_KERNEL);
		}
	}

	/* 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;
		call_usermodehelper (argv[0], argv, envp, 0);
	}

exit:
	kfree(devpath);
	kfree(buffer);
	kfree(envp);
	return;
}
EXPORT_SYMBOL_GPL(kobject_uevent);

/**
 * add_uevent_var - helper for creating event variables
 * @envp: Pointer to table of environment variables, as passed into
 * uevent() method.
 * @num_envp: Number of environment variable slots available, as
 * passed into uevent() method.
 * @cur_index: Pointer to current index into @envp.  It should be
 * initialized to 0 before the first call to add_uevent_var(),
 * and will be incremented on success.
 * @buffer: Pointer to buffer for environment variables, as passed
 * into uevent() method.
 * @buffer_size: Length of @buffer, as passed into uevent() method.
 * @cur_len: Pointer to current length of space used in @buffer.
 * Should be initialized to 0 before the first call to
 * add_uevent_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_uevent_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 kobject_uevent()
	 * 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_GPL(add_uevent_var);

static int __init kobject_uevent_init(void)
{
	uevent_sock = netlink_kernel_create(NETLINK_KOBJECT_UEVENT, 1, 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 /* CONFIG_HOTPLUG */
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>
	18	#include <linux/socket.h>
	19	#include <linux/skbuff.h>
	20	#include <linux/netlink.h>
	21	#include <linux/string.h>
1da177e4 LT	22	#include <linux/kobject.h>
	23	#include <net/sock.h>
	24
d87499ed	25	#define BUFFER_SIZE 2048 /* buffer for the variables */
1da177e4 LT	26	#define NUM_ENVP 32 /* number of env pointers */
1da177e4 LT	27
f743ca5e	28	#if defined(CONFIG_HOTPLUG) && defined(CONFIG_NET)
51107301 JN	29	u64 uevent_seqnum;
51107301 JN	30	char uevent_helper[UEVENT_HELPER_PATH_LEN] = "/sbin/hotplug";
0296b228	31	static DEFINE_SPINLOCK(sequence_lock);
5f123fbd	32	static struct sock *uevent_sock;
0296b228	33
1da177e4 LT	34	static char *action_to_string(enum kobject_action action)
	35	{
	36	switch (action) {
	37	case KOBJ_ADD:
	38	return "add";
	39	case KOBJ_REMOVE:
	40	return "remove";
	41	case KOBJ_CHANGE:
	42	return "change";
fa675765 GKH	43	case KOBJ_MOUNT:
	44	return "mount";
	45	case KOBJ_UMOUNT:
	46	return "umount";
1da177e4 LT	47	case KOBJ_OFFLINE:
	48	return "offline";
	49	case KOBJ_ONLINE:
	50	return "online";
	51	default:
	52	return NULL;
	53	}
	54	}
1da177e4	55
1da177e4	56	/**
312c004d	57	* kobject_uevent - notify userspace by ending an uevent
1da177e4	58	*
312c004d	59	* @action: action that is happening (usually KOBJ_ADD and KOBJ_REMOVE)
1da177e4 LT	60	* @kobj: struct kobject that the action is happening to
1da177e4 LT	61	*/
312c004d	62	void kobject_uevent(struct kobject *kobj, enum kobject_action action)
1da177e4	63	{
5f123fbd KS	64	char **envp;
5f123fbd KS	65	char *buffer;
1da177e4	66	char *scratch;
5f123fbd KS	67	const char *action_string;
	68	const char *devpath = NULL;
	69	const char *subsystem;
	70	struct kobject *top_kobj;
	71	struct kset *kset;
312c004d	72	struct kset_uevent_ops *uevent_ops;
5f123fbd KS	73	u64 seq;
5f123fbd KS	74	char *seq_buff;
1da177e4 LT	75	int i = 0;
1da177e4 LT	76	int retval;
1da177e4	77
5f123fbd KS	78	pr_debug("%s\n", __FUNCTION__);
	79
	80	action_string = action_to_string(action);
	81	if (!action_string)
	82	return;
	83
	84	/* search the kset we belong to */
	85	top_kobj = kobj;
1da177e4 LT	86	if (!top_kobj->kset && top_kobj->parent) {
	87	do {
	88	top_kobj = top_kobj->parent;
	89	} while (!top_kobj->kset && top_kobj->parent);
	90	}
5f123fbd	91	if (!top_kobj->kset)
1da177e4 LT	92	return;
1da177e4 LT	93
5f123fbd	94	kset = top_kobj->kset;
312c004d	95	uevent_ops = kset->uevent_ops;
1da177e4	96
5f123fbd	97	/* skip the event, if the filter returns zero. */
312c004d KS	98	if (uevent_ops && uevent_ops->filter)
312c004d KS	99	if (!uevent_ops->filter(kset, kobj))
1da177e4	100	return;
1da177e4	101
5f123fbd KS	102	/* environment index */
5f123fbd KS	103	envp = kzalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL);
1da177e4 LT	104	if (!envp)
1da177e4 LT	105	return;
1da177e4	106
5f123fbd	107	/* environment values */
1da177e4 LT	108	buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL);
	109	if (!buffer)
	110	goto exit;
	111
5f123fbd KS	112	/* complete object path */
	113	devpath = kobject_get_path(kobj, GFP_KERNEL);
	114	if (!devpath)
	115	goto exit;
1da177e4	116
5f123fbd	117	/* originating subsystem */
312c004d KS	118	if (uevent_ops && uevent_ops->name)
312c004d KS	119	subsystem = uevent_ops->name(kset, kobj);
5f123fbd KS	120	else
5f123fbd KS	121	subsystem = kobject_name(&kset->kobj);
1da177e4	122
5f123fbd KS	123	/* event environemnt for helper process only */
	124	envp[i++] = "HOME=/";
	125	envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
1da177e4	126
5f123fbd	127	/* default keys */
1da177e4	128	scratch = buffer;
1da177e4 LT	129	envp [i++] = scratch;
1da177e4 LT	130	scratch += sprintf(scratch, "ACTION=%s", action_string) + 1;
1da177e4	131	envp [i++] = scratch;
5f123fbd	132	scratch += sprintf (scratch, "DEVPATH=%s", devpath) + 1;
1da177e4	133	envp [i++] = scratch;
5f123fbd	134	scratch += sprintf(scratch, "SUBSYSTEM=%s", subsystem) + 1;
1da177e4	135
5f123fbd	136	/* just reserve the space, overwrite it after kset call has returned */
1da177e4 LT	137	envp[i++] = seq_buff = scratch;
	138	scratch += strlen("SEQNUM=18446744073709551616") + 1;
	139
5f123fbd	140	/* let the kset specific function add its stuff */
312c004d KS	141	if (uevent_ops && uevent_ops->uevent) {
312c004d KS	142	retval = uevent_ops->uevent(kset, kobj,
1da177e4 LT	143	&envp[i], NUM_ENVP - i, scratch,
	144	BUFFER_SIZE - (scratch - buffer));
	145	if (retval) {
312c004d	146	pr_debug ("%s - uevent() returned %d\n",
1da177e4 LT	147	__FUNCTION__, retval);
	148	goto exit;
	149	}
	150	}
	151
5f123fbd	152	/* we will send an event, request a new sequence number */
1da177e4	153	spin_lock(&sequence_lock);
312c004d	154	seq = ++uevent_seqnum;
1da177e4 LT	155	spin_unlock(&sequence_lock);
	156	sprintf(seq_buff, "SEQNUM=%llu", (unsigned long long)seq);
	157
5f123fbd KS	158	/* send netlink message */
	159	if (uevent_sock) {
	160	struct sk_buff *skb;
	161	size_t len;
	162
	163	/* allocate message with the maximum possible size */
	164	len = strlen(action_string) + strlen(devpath) + 2;
	165	skb = alloc_skb(len + BUFFER_SIZE, GFP_KERNEL);
	166	if (skb) {
	167	/* add header */
	168	scratch = skb_put(skb, len);
	169	sprintf(scratch, "%s@%s", action_string, devpath);
	170
	171	/* copy keys to our continuous event payload buffer */
	172	for (i = 2; envp[i]; i++) {
	173	len = strlen(envp[i]) + 1;
	174	scratch = skb_put(skb, len);
	175	strcpy(scratch, envp[i]);
	176	}
	177
	178	NETLINK_CB(skb).dst_group = 1;
	179	netlink_broadcast(uevent_sock, skb, 0, 1, GFP_KERNEL);
	180	}
	181	}
1da177e4	182
5f123fbd	183	/* call uevent_helper, usually only enabled during early boot */
312c004d	184	if (uevent_helper[0]) {
5f123fbd	185	char *argv [3];
1da177e4	186
312c004d	187	argv [0] = uevent_helper;
5f123fbd KS	188	argv [1] = (char *)subsystem;
	189	argv [2] = NULL;
	190	call_usermodehelper (argv[0], argv, envp, 0);
	191	}
1da177e4 LT	192
1da177e4 LT	193	exit:
5f123fbd	194	kfree(devpath);
1da177e4 LT	195	kfree(buffer);
	196	kfree(envp);
	197	return;
	198	}
312c004d	199	EXPORT_SYMBOL_GPL(kobject_uevent);
1da177e4 LT	200
1da177e4 LT	201	/**
312c004d	202	* add_uevent_var - helper for creating event variables
1da177e4	203	* @envp: Pointer to table of environment variables, as passed into
312c004d	204	* uevent() method.
1da177e4	205	* @num_envp: Number of environment variable slots available, as
312c004d	206	* passed into uevent() method.
1da177e4	207	* @cur_index: Pointer to current index into @envp. It should be
312c004d	208	* initialized to 0 before the first call to add_uevent_var(),
1da177e4 LT	209	* and will be incremented on success.
1da177e4 LT	210	* @buffer: Pointer to buffer for environment variables, as passed
312c004d KS	211	* into uevent() method.
312c004d KS	212	* @buffer_size: Length of @buffer, as passed into uevent() method.
1da177e4 LT	213	* @cur_len: Pointer to current length of space used in @buffer.
1da177e4 LT	214	* Should be initialized to 0 before the first call to
312c004d	215	* add_uevent_var(), and will be incremented on success.
1da177e4 LT	216	* @format: Format for creating environment variable (of the form
	217	* "XXX=%x") for snprintf().
	218	*
	219	* Returns 0 if environment variable was added successfully or -ENOMEM
	220	* if no space was available.
	221	*/
312c004d KS	222	int add_uevent_var(char *envp, int num_envp, int cur_index,
	223	char buffer, int buffer_size, int cur_len,
	224	const char *format, ...)
1da177e4 LT	225	{
	226	va_list args;
	227
	228	/*
	229	* We check against num_envp - 1 to make sure there is at
312c004d KS	230	* least one slot left after we return, since kobject_uevent()
312c004d KS	231	* needs to set the last slot to NULL.
1da177e4 LT	232	*/
	233	if (*cur_index >= num_envp - 1)
	234	return -ENOMEM;
	235
	236	envp[cur_index] = buffer + cur_len;
	237
	238	va_start(args, format);
	239	cur_len += vsnprintf(envp[cur_index],
	240	max(buffer_size - *cur_len, 0),
	241	format, args) + 1;
	242	va_end(args);
	243
	244	if (*cur_len > buffer_size)
	245	return -ENOMEM;
	246
	247	(*cur_index)++;
	248	return 0;
	249	}
312c004d	250	EXPORT_SYMBOL_GPL(add_uevent_var);
1da177e4	251
5f123fbd KS	252	static int __init kobject_uevent_init(void)
	253	{
	254	uevent_sock = netlink_kernel_create(NETLINK_KOBJECT_UEVENT, 1, NULL,
	255	THIS_MODULE);
	256
	257	if (!uevent_sock) {
	258	printk(KERN_ERR
	259	"kobject_uevent: unable to create netlink socket!\n");
	260	return -ENODEV;
	261	}
	262
	263	return 0;
	264	}
	265
	266	postcore_initcall(kobject_uevent_init);
	267
1da177e4	268	#endif /* CONFIG_HOTPLUG */