/*
* 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 variables */
#define NUM_ENVP 32 /* number of env pointers */
#if defined(CONFIG_HOTPLUG)
char uevent_helper[UEVENT_HELPER_PATH_LEN] = "/sbin/hotplug";
u64 uevent_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_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 */
