/*
* 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 through 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, gfp_t 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_group = 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, gfp_t 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, 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);
#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 */
