[net-next-2.6.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)
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)
0296b228	29	static DEFINE_SPINLOCK(sequence_lock);
5f123fbd	30	static struct sock *uevent_sock;
0296b228	31
1da177e4 LT	32	static char *action_to_string(enum kobject_action action)
	33	{
	34	switch (action) {
	35	case KOBJ_ADD:
	36	return "add";
	37	case KOBJ_REMOVE:
	38	return "remove";
	39	case KOBJ_CHANGE:
	40	return "change";
fa675765 GKH	41	case KOBJ_MOUNT:
	42	return "mount";
	43	case KOBJ_UMOUNT:
	44	return "umount";
1da177e4 LT	45	case KOBJ_OFFLINE:
	46	return "offline";
	47	case KOBJ_ONLINE:
	48	return "online";
	49	default:
	50	return NULL;
	51	}
	52	}
1da177e4	53
1da177e4	54	/**
312c004d	55	* kobject_uevent - notify userspace by ending an uevent
1da177e4	56	*
312c004d	57	* @action: action that is happening (usually KOBJ_ADD and KOBJ_REMOVE)
1da177e4 LT	58	* @kobj: struct kobject that the action is happening to
1da177e4 LT	59	*/
312c004d	60	void kobject_uevent(struct kobject *kobj, enum kobject_action action)
1da177e4	61	{
5f123fbd KS	62	char **envp;
5f123fbd KS	63	char *buffer;
1da177e4	64	char *scratch;
5f123fbd KS	65	const char *action_string;
	66	const char *devpath = NULL;
	67	const char *subsystem;
	68	struct kobject *top_kobj;
	69	struct kset *kset;
312c004d	70	struct kset_uevent_ops *uevent_ops;
5f123fbd KS	71	u64 seq;
5f123fbd KS	72	char *seq_buff;
1da177e4 LT	73	int i = 0;
1da177e4 LT	74	int retval;
1da177e4	75
5f123fbd KS	76	pr_debug("%s\n", __FUNCTION__);
	77
	78	action_string = action_to_string(action);
	79	if (!action_string)
	80	return;
	81
	82	/* search the kset we belong to */
	83	top_kobj = kobj;
1da177e4 LT	84	if (!top_kobj->kset && top_kobj->parent) {
	85	do {
	86	top_kobj = top_kobj->parent;
	87	} while (!top_kobj->kset && top_kobj->parent);
	88	}
5f123fbd	89	if (!top_kobj->kset)
1da177e4 LT	90	return;
1da177e4 LT	91
5f123fbd	92	kset = top_kobj->kset;
312c004d	93	uevent_ops = kset->uevent_ops;
1da177e4	94
5f123fbd	95	/* skip the event, if the filter returns zero. */
312c004d KS	96	if (uevent_ops && uevent_ops->filter)
312c004d KS	97	if (!uevent_ops->filter(kset, kobj))
1da177e4	98	return;
1da177e4	99
5f123fbd KS	100	/* environment index */
5f123fbd KS	101	envp = kzalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL);
1da177e4 LT	102	if (!envp)
1da177e4 LT	103	return;
1da177e4	104
5f123fbd	105	/* environment values */
1da177e4 LT	106	buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL);
	107	if (!buffer)
	108	goto exit;
	109
5f123fbd KS	110	/* complete object path */
	111	devpath = kobject_get_path(kobj, GFP_KERNEL);
	112	if (!devpath)
	113	goto exit;
1da177e4	114
5f123fbd	115	/* originating subsystem */
312c004d KS	116	if (uevent_ops && uevent_ops->name)
312c004d KS	117	subsystem = uevent_ops->name(kset, kobj);
5f123fbd KS	118	else
5f123fbd KS	119	subsystem = kobject_name(&kset->kobj);
1da177e4	120
5f123fbd KS	121	/* event environemnt for helper process only */
	122	envp[i++] = "HOME=/";
	123	envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
1da177e4	124
5f123fbd	125	/* default keys */
1da177e4	126	scratch = buffer;
1da177e4 LT	127	envp [i++] = scratch;
1da177e4 LT	128	scratch += sprintf(scratch, "ACTION=%s", action_string) + 1;
1da177e4	129	envp [i++] = scratch;
5f123fbd	130	scratch += sprintf (scratch, "DEVPATH=%s", devpath) + 1;
1da177e4	131	envp [i++] = scratch;
5f123fbd	132	scratch += sprintf(scratch, "SUBSYSTEM=%s", subsystem) + 1;
1da177e4	133
5f123fbd	134	/* just reserve the space, overwrite it after kset call has returned */
1da177e4 LT	135	envp[i++] = seq_buff = scratch;
	136	scratch += strlen("SEQNUM=18446744073709551616") + 1;
	137
5f123fbd	138	/* let the kset specific function add its stuff */
312c004d KS	139	if (uevent_ops && uevent_ops->uevent) {
312c004d KS	140	retval = uevent_ops->uevent(kset, kobj,
1da177e4 LT	141	&envp[i], NUM_ENVP - i, scratch,
	142	BUFFER_SIZE - (scratch - buffer));
	143	if (retval) {
312c004d	144	pr_debug ("%s - uevent() returned %d\n",
1da177e4 LT	145	__FUNCTION__, retval);
	146	goto exit;
	147	}
	148	}
	149
5f123fbd	150	/* we will send an event, request a new sequence number */
1da177e4	151	spin_lock(&sequence_lock);
312c004d	152	seq = ++uevent_seqnum;
1da177e4 LT	153	spin_unlock(&sequence_lock);
	154	sprintf(seq_buff, "SEQNUM=%llu", (unsigned long long)seq);
	155
5f123fbd KS	156	/* send netlink message */
	157	if (uevent_sock) {
	158	struct sk_buff *skb;
	159	size_t len;
	160
	161	/* allocate message with the maximum possible size */
	162	len = strlen(action_string) + strlen(devpath) + 2;
	163	skb = alloc_skb(len + BUFFER_SIZE, GFP_KERNEL);
	164	if (skb) {
	165	/* add header */
	166	scratch = skb_put(skb, len);
	167	sprintf(scratch, "%s@%s", action_string, devpath);
	168
	169	/* copy keys to our continuous event payload buffer */
	170	for (i = 2; envp[i]; i++) {
	171	len = strlen(envp[i]) + 1;
	172	scratch = skb_put(skb, len);
	173	strcpy(scratch, envp[i]);
	174	}
	175
	176	NETLINK_CB(skb).dst_group = 1;
	177	netlink_broadcast(uevent_sock, skb, 0, 1, GFP_KERNEL);
	178	}
	179	}
1da177e4	180
5f123fbd	181	/* call uevent_helper, usually only enabled during early boot */
312c004d	182	if (uevent_helper[0]) {
5f123fbd	183	char *argv [3];
1da177e4	184
312c004d	185	argv [0] = uevent_helper;
5f123fbd KS	186	argv [1] = (char *)subsystem;
	187	argv [2] = NULL;
	188	call_usermodehelper (argv[0], argv, envp, 0);
	189	}
1da177e4 LT	190
1da177e4 LT	191	exit:
5f123fbd	192	kfree(devpath);
1da177e4 LT	193	kfree(buffer);
	194	kfree(envp);
	195	return;
	196	}
312c004d	197	EXPORT_SYMBOL_GPL(kobject_uevent);
1da177e4 LT	198
1da177e4 LT	199	/**
312c004d	200	* add_uevent_var - helper for creating event variables
1da177e4	201	* @envp: Pointer to table of environment variables, as passed into
312c004d	202	* uevent() method.
1da177e4	203	* @num_envp: Number of environment variable slots available, as
312c004d	204	* passed into uevent() method.
1da177e4	205	* @cur_index: Pointer to current index into @envp. It should be
312c004d	206	* initialized to 0 before the first call to add_uevent_var(),
1da177e4 LT	207	* and will be incremented on success.
1da177e4 LT	208	* @buffer: Pointer to buffer for environment variables, as passed
312c004d KS	209	* into uevent() method.
312c004d KS	210	* @buffer_size: Length of @buffer, as passed into uevent() method.
1da177e4 LT	211	* @cur_len: Pointer to current length of space used in @buffer.
1da177e4 LT	212	* Should be initialized to 0 before the first call to
312c004d	213	* add_uevent_var(), and will be incremented on success.
1da177e4 LT	214	* @format: Format for creating environment variable (of the form
	215	* "XXX=%x") for snprintf().
	216	*
	217	* Returns 0 if environment variable was added successfully or -ENOMEM
	218	* if no space was available.
	219	*/
312c004d KS	220	int add_uevent_var(char *envp, int num_envp, int cur_index,
	221	char buffer, int buffer_size, int cur_len,
	222	const char *format, ...)
1da177e4 LT	223	{
	224	va_list args;
	225
	226	/*
	227	* We check against num_envp - 1 to make sure there is at
312c004d KS	228	* least one slot left after we return, since kobject_uevent()
312c004d KS	229	* needs to set the last slot to NULL.
1da177e4 LT	230	*/
	231	if (*cur_index >= num_envp - 1)
	232	return -ENOMEM;
	233
	234	envp[cur_index] = buffer + cur_len;
	235
	236	va_start(args, format);
	237	cur_len += vsnprintf(envp[cur_index],
	238	max(buffer_size - *cur_len, 0),
	239	format, args) + 1;
	240	va_end(args);
	241
	242	if (*cur_len > buffer_size)
	243	return -ENOMEM;
	244
	245	(*cur_index)++;
	246	return 0;
	247	}
312c004d	248	EXPORT_SYMBOL_GPL(add_uevent_var);
1da177e4	249
5f123fbd KS	250	static int __init kobject_uevent_init(void)
	251	{
	252	uevent_sock = netlink_kernel_create(NETLINK_KOBJECT_UEVENT, 1, NULL,
	253	THIS_MODULE);
	254
	255	if (!uevent_sock) {
	256	printk(KERN_ERR
	257	"kobject_uevent: unable to create netlink socket!\n");
	258	return -ENODEV;
	259	}
	260
	261	return 0;
	262	}
	263
	264	postcore_initcall(kobject_uevent_init);
	265
1da177e4	266	#endif /* CONFIG_HOTPLUG */