337 lines
8.4 KiB
C
337 lines
8.4 KiB
C
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/*
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* kernel userspace event delivery
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*
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* Copyright (C) 2004 Red Hat, Inc. All rights reserved.
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* Copyright (C) 2004 Novell, Inc. All rights reserved.
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* Copyright (C) 2004 IBM, Inc. All rights reserved.
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*
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* Licensed under the GNU GPL v2.
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*
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* Authors:
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* Robert Love <rml@novell.com>
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* Kay Sievers <kay.sievers@vrfy.org>
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* Arjan van de Ven <arjanv@redhat.com>
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* Greg Kroah-Hartman <greg@kroah.com>
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*/
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#include <linux/spinlock.h>
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#include <linux/string.h>
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#include <linux/kobject.h>
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#include <linux/module.h>
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#include <linux/socket.h>
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#include <linux/skbuff.h>
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#include <linux/netlink.h>
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#include <net/sock.h>
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u64 uevent_seqnum;
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char uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH;
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static DEFINE_SPINLOCK(sequence_lock);
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#if defined(CONFIG_NET)
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static struct sock *uevent_sock;
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#endif
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/* the strings here must match the enum in include/linux/kobject.h */
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static const char *kobject_actions[] = {
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[KOBJ_ADD] = "add",
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[KOBJ_REMOVE] = "remove",
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[KOBJ_CHANGE] = "change",
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[KOBJ_MOVE] = "move",
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[KOBJ_ONLINE] = "online",
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[KOBJ_OFFLINE] = "offline",
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};
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/**
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* kobject_action_type - translate action string to numeric type
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*
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* @buf: buffer containing the action string, newline is ignored
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* @len: length of buffer
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* @type: pointer to the location to store the action type
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*
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* Returns 0 if the action string was recognized.
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*/
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int kobject_action_type(const char *buf, size_t count,
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enum kobject_action *type)
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{
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enum kobject_action action;
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int ret = -EINVAL;
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if (count && (buf[count-1] == '\n' || buf[count-1] == '\0'))
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count--;
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if (!count)
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goto out;
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for (action = 0; action < ARRAY_SIZE(kobject_actions); action++) {
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if (strncmp(kobject_actions[action], buf, count) != 0)
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continue;
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if (kobject_actions[action][count] != '\0')
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continue;
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*type = action;
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ret = 0;
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break;
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}
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out:
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return ret;
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}
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/**
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* kobject_uevent_env - send an uevent with environmental data
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*
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* @action: action that is happening
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* @kobj: struct kobject that the action is happening to
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* @envp_ext: pointer to environmental data
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*
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* Returns 0 if kobject_uevent() is completed with success or the
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* corresponding error when it fails.
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*/
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int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
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char *envp_ext[])
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{
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struct kobj_uevent_env *env;
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const char *action_string = kobject_actions[action];
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const char *devpath = NULL;
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const char *subsystem;
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struct kobject *top_kobj;
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struct kset *kset;
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struct kset_uevent_ops *uevent_ops;
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u64 seq;
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int i = 0;
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int retval = 0;
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pr_debug("kobject: '%s' (%p): %s\n",
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kobject_name(kobj), kobj, __func__);
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/* search the kset we belong to */
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top_kobj = kobj;
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while (!top_kobj->kset && top_kobj->parent)
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top_kobj = top_kobj->parent;
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if (!top_kobj->kset) {
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pr_debug("kobject: '%s' (%p): %s: attempted to send uevent "
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"without kset!\n", kobject_name(kobj), kobj,
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__func__);
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return -EINVAL;
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}
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kset = top_kobj->kset;
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uevent_ops = kset->uevent_ops;
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/* skip the event, if uevent_suppress is set*/
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if (kobj->uevent_suppress) {
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pr_debug("kobject: '%s' (%p): %s: uevent_suppress "
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"caused the event to drop!\n",
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kobject_name(kobj), kobj, __func__);
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return 0;
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}
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/* skip the event, if the filter returns zero. */
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if (uevent_ops && uevent_ops->filter)
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if (!uevent_ops->filter(kset, kobj)) {
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pr_debug("kobject: '%s' (%p): %s: filter function "
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"caused the event to drop!\n",
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kobject_name(kobj), kobj, __func__);
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return 0;
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}
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/* originating subsystem */
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if (uevent_ops && uevent_ops->name)
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subsystem = uevent_ops->name(kset, kobj);
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else
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subsystem = kobject_name(&kset->kobj);
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if (!subsystem) {
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pr_debug("kobject: '%s' (%p): %s: unset subsystem caused the "
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"event to drop!\n", kobject_name(kobj), kobj,
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__func__);
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return 0;
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}
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/* environment buffer */
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env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
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if (!env)
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return -ENOMEM;
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/* complete object path */
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devpath = kobject_get_path(kobj, GFP_KERNEL);
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if (!devpath) {
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retval = -ENOENT;
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goto exit;
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}
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/* default keys */
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retval = add_uevent_var(env, "ACTION=%s", action_string);
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if (retval)
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goto exit;
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retval = add_uevent_var(env, "DEVPATH=%s", devpath);
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if (retval)
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goto exit;
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retval = add_uevent_var(env, "SUBSYSTEM=%s", subsystem);
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if (retval)
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goto exit;
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/* keys passed in from the caller */
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if (envp_ext) {
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for (i = 0; envp_ext[i]; i++) {
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retval = add_uevent_var(env, "%s", envp_ext[i]);
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if (retval)
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goto exit;
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}
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}
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/* let the kset specific function add its stuff */
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if (uevent_ops && uevent_ops->uevent) {
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retval = uevent_ops->uevent(kset, kobj, env);
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if (retval) {
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pr_debug("kobject: '%s' (%p): %s: uevent() returned "
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"%d\n", kobject_name(kobj), kobj,
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__func__, retval);
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goto exit;
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}
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}
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/*
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* Mark "add" and "remove" events in the object to ensure proper
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* events to userspace during automatic cleanup. If the object did
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* send an "add" event, "remove" will automatically generated by
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* the core, if not already done by the caller.
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*/
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if (action == KOBJ_ADD)
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kobj->state_add_uevent_sent = 1;
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else if (action == KOBJ_REMOVE)
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kobj->state_remove_uevent_sent = 1;
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/* we will send an event, so request a new sequence number */
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spin_lock(&sequence_lock);
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seq = ++uevent_seqnum;
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spin_unlock(&sequence_lock);
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retval = add_uevent_var(env, "SEQNUM=%llu", (unsigned long long)seq);
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if (retval)
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goto exit;
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#if defined(CONFIG_NET)
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/* send netlink message */
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if (uevent_sock) {
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struct sk_buff *skb;
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size_t len;
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/* allocate message with the maximum possible size */
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len = strlen(action_string) + strlen(devpath) + 2;
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skb = alloc_skb(len + env->buflen, GFP_KERNEL);
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if (skb) {
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char *scratch;
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/* add header */
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scratch = skb_put(skb, len);
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sprintf(scratch, "%s@%s", action_string, devpath);
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/* copy keys to our continuous event payload buffer */
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for (i = 0; i < env->envp_idx; i++) {
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len = strlen(env->envp[i]) + 1;
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scratch = skb_put(skb, len);
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strcpy(scratch, env->envp[i]);
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}
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NETLINK_CB(skb).dst_group = 1;
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retval = netlink_broadcast(uevent_sock, skb, 0, 1,
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GFP_KERNEL);
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/* ENOBUFS should be handled in userspace */
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if (retval == -ENOBUFS)
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retval = 0;
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} else
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retval = -ENOMEM;
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}
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#endif
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/* call uevent_helper, usually only enabled during early boot */
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if (uevent_helper[0]) {
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char *argv [3];
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argv [0] = uevent_helper;
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argv [1] = (char *)subsystem;
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argv [2] = NULL;
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retval = add_uevent_var(env, "HOME=/");
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if (retval)
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goto exit;
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retval = add_uevent_var(env,
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"PATH=/sbin:/bin:/usr/sbin:/usr/bin");
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if (retval)
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goto exit;
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retval = call_usermodehelper(argv[0], argv,
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env->envp, UMH_WAIT_EXEC);
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}
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exit:
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kfree(devpath);
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kfree(env);
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return retval;
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}
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EXPORT_SYMBOL_GPL(kobject_uevent_env);
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/**
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* kobject_uevent - notify userspace by ending an uevent
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*
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* @action: action that is happening
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* @kobj: struct kobject that the action is happening to
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*
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* Returns 0 if kobject_uevent() is completed with success or the
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* corresponding error when it fails.
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*/
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int kobject_uevent(struct kobject *kobj, enum kobject_action action)
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{
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return kobject_uevent_env(kobj, action, NULL);
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}
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EXPORT_SYMBOL_GPL(kobject_uevent);
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/**
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* add_uevent_var - add key value string to the environment buffer
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* @env: environment buffer structure
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* @format: printf format for the key=value pair
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*
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* Returns 0 if environment variable was added successfully or -ENOMEM
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* if no space was available.
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*/
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int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
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{
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va_list args;
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int len;
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if (env->envp_idx >= ARRAY_SIZE(env->envp)) {
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WARN(1, KERN_ERR "add_uevent_var: too many keys\n");
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return -ENOMEM;
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}
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va_start(args, format);
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len = vsnprintf(&env->buf[env->buflen],
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sizeof(env->buf) - env->buflen,
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format, args);
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va_end(args);
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if (len >= (sizeof(env->buf) - env->buflen)) {
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WARN(1, KERN_ERR "add_uevent_var: buffer size too small\n");
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return -ENOMEM;
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}
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env->envp[env->envp_idx++] = &env->buf[env->buflen];
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env->buflen += len + 1;
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return 0;
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}
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EXPORT_SYMBOL_GPL(add_uevent_var);
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#if defined(CONFIG_NET)
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static int __init kobject_uevent_init(void)
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{
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uevent_sock = netlink_kernel_create(&init_net, NETLINK_KOBJECT_UEVENT,
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1, NULL, NULL, THIS_MODULE);
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if (!uevent_sock) {
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printk(KERN_ERR
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"kobject_uevent: unable to create netlink socket!\n");
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return -ENODEV;
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}
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netlink_set_nonroot(NETLINK_KOBJECT_UEVENT, NL_NONROOT_RECV);
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return 0;
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}
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postcore_initcall(kobject_uevent_init);
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#endif
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