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

#if defined(CONFIG_HOTPLUG)
char hotplug_path[HOTPLUG_PATH_LEN] = "/sbin/hotplug";
u64 hotplug_seqnum;
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_OFFLINE:
		return "offline";
	case KOBJ_ONLINE:
		return "online";
	default:
		return NULL;
	}
}

/**
 * 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 **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_hotplug_ops *hotplug_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;
	hotplug_ops = kset->hotplug_ops;

	/*  skip the event, if the filter returns zero. */
	if (hotplug_ops && hotplug_ops->filter)
		if (!hotplug_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 (hotplug_ops && hotplug_ops->name)
		subsystem = hotplug_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 (hotplug_ops && hotplug_ops->hotplug) {
		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;
		}
	}

	/* we will send an event, request a new sequence number */
	spin_lock(&sequence_lock);
	seq = ++hotplug_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 (hotplug_path[0]) {
		char *argv [3];

		argv [0] = hotplug_path;
		argv [1] = (char *)subsystem;
		argv [2] = NULL;
		call_usermodehelper (argv[0], argv, envp, 0);
	}

exit:
	kfree(devpath);
	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);

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
	25	#define BUFFER_SIZE 1024 /* buffer for the hotplug env */
	26	#define NUM_ENVP 32 /* number of env pointers */
	27
0296b228 KS	28	#if defined(CONFIG_HOTPLUG)
	29	char hotplug_path[HOTPLUG_PATH_LEN] = "/sbin/hotplug";
	30	u64 hotplug_seqnum;
	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";
1da177e4 LT	43	case KOBJ_OFFLINE:
	44	return "offline";
	45	case KOBJ_ONLINE:
	46	return "online";
	47	default:
	48	return NULL;
	49	}
	50	}
1da177e4	51
1da177e4 LT	52	/**
	53	* kobject_hotplug - notify userspace by executing /sbin/hotplug
	54	*
	55	* @action: action that is happening (usually "ADD" or "REMOVE")
	56	* @kobj: struct kobject that the action is happening to
	57	*/
	58	void kobject_hotplug(struct kobject *kobj, enum kobject_action action)
	59	{
5f123fbd KS	60	char **envp;
5f123fbd KS	61	char *buffer;
1da177e4	62	char *scratch;
5f123fbd KS	63	const char *action_string;
	64	const char *devpath = NULL;
	65	const char *subsystem;
	66	struct kobject *top_kobj;
	67	struct kset *kset;
	68	struct kset_hotplug_ops *hotplug_ops;
	69	u64 seq;
	70	char *seq_buff;
1da177e4 LT	71	int i = 0;
1da177e4 LT	72	int retval;
1da177e4	73
5f123fbd KS	74	pr_debug("%s\n", __FUNCTION__);
	75
	76	action_string = action_to_string(action);
	77	if (!action_string)
	78	return;
	79
	80	/* search the kset we belong to */
	81	top_kobj = kobj;
1da177e4 LT	82	if (!top_kobj->kset && top_kobj->parent) {
	83	do {
	84	top_kobj = top_kobj->parent;
	85	} while (!top_kobj->kset && top_kobj->parent);
	86	}
5f123fbd	87	if (!top_kobj->kset)
1da177e4 LT	88	return;
1da177e4 LT	89
5f123fbd KS	90	kset = top_kobj->kset;
5f123fbd KS	91	hotplug_ops = kset->hotplug_ops;
1da177e4	92
5f123fbd KS	93	/* skip the event, if the filter returns zero. */
5f123fbd KS	94	if (hotplug_ops && hotplug_ops->filter)
1da177e4 LT	95	if (!hotplug_ops->filter(kset, kobj))
1da177e4 LT	96	return;
1da177e4	97
5f123fbd KS	98	/* environment index */
5f123fbd KS	99	envp = kzalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL);
1da177e4 LT	100	if (!envp)
1da177e4 LT	101	return;
1da177e4	102
5f123fbd	103	/* environment values */
1da177e4 LT	104	buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL);
	105	if (!buffer)
	106	goto exit;
	107
5f123fbd KS	108	/* complete object path */
	109	devpath = kobject_get_path(kobj, GFP_KERNEL);
	110	if (!devpath)
	111	goto exit;
1da177e4	112
5f123fbd KS	113	/* originating subsystem */
	114	if (hotplug_ops && hotplug_ops->name)
	115	subsystem = hotplug_ops->name(kset, kobj);
	116	else
	117	subsystem = kobject_name(&kset->kobj);
1da177e4	118
5f123fbd KS	119	/* event environemnt for helper process only */
	120	envp[i++] = "HOME=/";
	121	envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
1da177e4	122
5f123fbd	123	/* default keys */
1da177e4	124	scratch = buffer;
1da177e4 LT	125	envp [i++] = scratch;
1da177e4 LT	126	scratch += sprintf(scratch, "ACTION=%s", action_string) + 1;
1da177e4	127	envp [i++] = scratch;
5f123fbd	128	scratch += sprintf (scratch, "DEVPATH=%s", devpath) + 1;
1da177e4	129	envp [i++] = scratch;
5f123fbd	130	scratch += sprintf(scratch, "SUBSYSTEM=%s", subsystem) + 1;
1da177e4	131
5f123fbd	132	/* just reserve the space, overwrite it after kset call has returned */
1da177e4 LT	133	envp[i++] = seq_buff = scratch;
	134	scratch += strlen("SEQNUM=18446744073709551616") + 1;
	135
5f123fbd KS	136	/* let the kset specific function add its stuff */
5f123fbd KS	137	if (hotplug_ops && hotplug_ops->hotplug) {
1da177e4 LT	138	retval = hotplug_ops->hotplug (kset, kobj,
	139	&envp[i], NUM_ENVP - i, scratch,
	140	BUFFER_SIZE - (scratch - buffer));
	141	if (retval) {
	142	pr_debug ("%s - hotplug() returned %d\n",
	143	__FUNCTION__, retval);
	144	goto exit;
	145	}
	146	}
	147
5f123fbd	148	/* we will send an event, request a new sequence number */
1da177e4 LT	149	spin_lock(&sequence_lock);
	150	seq = ++hotplug_seqnum;
	151	spin_unlock(&sequence_lock);
	152	sprintf(seq_buff, "SEQNUM=%llu", (unsigned long long)seq);
	153
5f123fbd KS	154	/* send netlink message */
	155	if (uevent_sock) {
	156	struct sk_buff *skb;
	157	size_t len;
	158
	159	/* allocate message with the maximum possible size */
	160	len = strlen(action_string) + strlen(devpath) + 2;
	161	skb = alloc_skb(len + BUFFER_SIZE, GFP_KERNEL);
	162	if (skb) {
	163	/* add header */
	164	scratch = skb_put(skb, len);
	165	sprintf(scratch, "%s@%s", action_string, devpath);
	166
	167	/* copy keys to our continuous event payload buffer */
	168	for (i = 2; envp[i]; i++) {
	169	len = strlen(envp[i]) + 1;
	170	scratch = skb_put(skb, len);
	171	strcpy(scratch, envp[i]);
	172	}
	173
	174	NETLINK_CB(skb).dst_group = 1;
	175	netlink_broadcast(uevent_sock, skb, 0, 1, GFP_KERNEL);
	176	}
	177	}
1da177e4	178
5f123fbd KS	179	/* call uevent_helper, usually only enabled during early boot */
	180	if (hotplug_path[0]) {
	181	char *argv [3];
1da177e4	182
5f123fbd KS	183	argv [0] = hotplug_path;
	184	argv [1] = (char *)subsystem;
	185	argv [2] = NULL;
	186	call_usermodehelper (argv[0], argv, envp, 0);
	187	}
1da177e4 LT	188
1da177e4 LT	189	exit:
5f123fbd	190	kfree(devpath);
1da177e4 LT	191	kfree(buffer);
	192	kfree(envp);
	193	return;
	194	}
	195	EXPORT_SYMBOL(kobject_hotplug);
	196
	197	/**
	198	* add_hotplug_env_var - helper for creating hotplug environment variables
	199	* @envp: Pointer to table of environment variables, as passed into
	200	* hotplug() method.
	201	* @num_envp: Number of environment variable slots available, as
	202	* passed into hotplug() method.
	203	* @cur_index: Pointer to current index into @envp. It should be
	204	* initialized to 0 before the first call to add_hotplug_env_var(),
	205	* and will be incremented on success.
	206	* @buffer: Pointer to buffer for environment variables, as passed
	207	* into hotplug() method.
	208	* @buffer_size: Length of @buffer, as passed into hotplug() method.
	209	* @cur_len: Pointer to current length of space used in @buffer.
	210	* Should be initialized to 0 before the first call to
	211	* add_hotplug_env_var(), and will be incremented on success.
	212	* @format: Format for creating environment variable (of the form
	213	* "XXX=%x") for snprintf().
	214	*
	215	* Returns 0 if environment variable was added successfully or -ENOMEM
	216	* if no space was available.
	217	*/
	218	int add_hotplug_env_var(char *envp, int num_envp, int cur_index,
	219	char buffer, int buffer_size, int cur_len,
	220	const char *format, ...)
	221	{
	222	va_list args;
	223
	224	/*
	225	* We check against num_envp - 1 to make sure there is at
	226	* least one slot left after we return, since the hotplug
	227	* method needs to set the last slot to NULL.
	228	*/
	229	if (*cur_index >= num_envp - 1)
	230	return -ENOMEM;
	231
	232	envp[cur_index] = buffer + cur_len;
	233
	234	va_start(args, format);
	235	cur_len += vsnprintf(envp[cur_index],
	236	max(buffer_size - *cur_len, 0),
	237	format, args) + 1;
	238	va_end(args);
	239
	240	if (*cur_len > buffer_size)
	241	return -ENOMEM;
	242
	243	(*cur_index)++;
	244	return 0;
	245	}
	246	EXPORT_SYMBOL(add_hotplug_env_var);
	247
5f123fbd KS	248	static int __init kobject_uevent_init(void)
	249	{
	250	uevent_sock = netlink_kernel_create(NETLINK_KOBJECT_UEVENT, 1, NULL,
	251	THIS_MODULE);
	252
	253	if (!uevent_sock) {
	254	printk(KERN_ERR
	255	"kobject_uevent: unable to create netlink socket!\n");
	256	return -ENODEV;
	257	}
	258
	259	return 0;
	260	}
	261
	262	postcore_initcall(kobject_uevent_init);
	263
1da177e4	264	#endif /* CONFIG_HOTPLUG */