664 lines
15 KiB
C
664 lines
15 KiB
C
// SPDX-License-Identifier: GPL-2.0
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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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* 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/export.h>
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#include <linux/kmod.h>
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#include <linux/slab.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 <linux/uuid.h>
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#include <linux/ctype.h>
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#include <net/sock.h>
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#include <net/net_namespace.h>
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u64 uevent_seqnum;
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#ifdef CONFIG_UEVENT_HELPER
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char uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH;
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#endif
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#ifdef CONFIG_NET
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struct uevent_sock {
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struct list_head list;
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struct sock *sk;
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};
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static LIST_HEAD(uevent_sock_list);
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#endif
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/* This lock protects uevent_seqnum and uevent_sock_list */
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static DEFINE_MUTEX(uevent_sock_mutex);
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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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[KOBJ_BIND] = "bind",
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[KOBJ_UNBIND] = "unbind",
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};
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static int kobject_action_type(const char *buf, size_t count,
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enum kobject_action *type,
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const char **args)
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{
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enum kobject_action action;
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size_t count_first;
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const char *args_start;
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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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args_start = strnchr(buf, count, ' ');
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if (args_start) {
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count_first = args_start - buf;
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args_start = args_start + 1;
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} else
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count_first = count;
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for (action = 0; action < ARRAY_SIZE(kobject_actions); action++) {
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if (strncmp(kobject_actions[action], buf, count_first) != 0)
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continue;
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if (kobject_actions[action][count_first] != '\0')
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continue;
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if (args)
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*args = args_start;
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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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static const char *action_arg_word_end(const char *buf, const char *buf_end,
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char delim)
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{
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const char *next = buf;
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while (next <= buf_end && *next != delim)
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if (!isalnum(*next++))
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return NULL;
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if (next == buf)
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return NULL;
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return next;
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}
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static int kobject_action_args(const char *buf, size_t count,
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struct kobj_uevent_env **ret_env)
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{
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struct kobj_uevent_env *env = NULL;
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const char *next, *buf_end, *key;
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int key_len;
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int r = -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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return -EINVAL;
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env = kzalloc(sizeof(*env), GFP_KERNEL);
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if (!env)
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return -ENOMEM;
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/* first arg is UUID */
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if (count < UUID_STRING_LEN || !uuid_is_valid(buf) ||
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add_uevent_var(env, "SYNTH_UUID=%.*s", UUID_STRING_LEN, buf))
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goto out;
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/*
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* the rest are custom environment variables in KEY=VALUE
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* format with ' ' delimiter between each KEY=VALUE pair
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*/
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next = buf + UUID_STRING_LEN;
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buf_end = buf + count - 1;
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while (next <= buf_end) {
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if (*next != ' ')
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goto out;
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/* skip the ' ', key must follow */
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key = ++next;
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if (key > buf_end)
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goto out;
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buf = next;
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next = action_arg_word_end(buf, buf_end, '=');
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if (!next || next > buf_end || *next != '=')
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goto out;
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key_len = next - buf;
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/* skip the '=', value must follow */
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if (++next > buf_end)
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goto out;
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buf = next;
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next = action_arg_word_end(buf, buf_end, ' ');
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if (!next)
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goto out;
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if (add_uevent_var(env, "SYNTH_ARG_%.*s=%.*s",
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key_len, key, (int) (next - buf), buf))
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goto out;
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}
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r = 0;
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out:
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if (r)
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kfree(env);
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else
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*ret_env = env;
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return r;
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}
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/**
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* kobject_synth_uevent - send synthetic uevent with arguments
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*
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* @kobj: struct kobject for which synthetic uevent is to be generated
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* @buf: buffer containing action type and action args, newline is ignored
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* @count: length of buffer
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*
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* Returns 0 if kobject_synthetic_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_synth_uevent(struct kobject *kobj, const char *buf, size_t count)
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{
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char *no_uuid_envp[] = { "SYNTH_UUID=0", NULL };
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enum kobject_action action;
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const char *action_args;
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struct kobj_uevent_env *env;
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const char *msg = NULL, *devpath;
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int r;
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r = kobject_action_type(buf, count, &action, &action_args);
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if (r) {
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msg = "unknown uevent action string\n";
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goto out;
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}
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if (!action_args) {
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r = kobject_uevent_env(kobj, action, no_uuid_envp);
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goto out;
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}
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r = kobject_action_args(action_args,
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count - (action_args - buf), &env);
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if (r == -EINVAL) {
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msg = "incorrect uevent action arguments\n";
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goto out;
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}
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if (r)
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goto out;
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r = kobject_uevent_env(kobj, action, env->envp);
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kfree(env);
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out:
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if (r) {
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devpath = kobject_get_path(kobj, GFP_KERNEL);
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printk(KERN_WARNING "synth uevent: %s: %s",
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devpath ?: "unknown device",
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msg ?: "failed to send uevent");
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kfree(devpath);
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}
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return r;
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}
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#ifdef CONFIG_NET
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static int kobj_bcast_filter(struct sock *dsk, struct sk_buff *skb, void *data)
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{
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struct kobject *kobj = data, *ksobj;
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const struct kobj_ns_type_operations *ops;
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ops = kobj_ns_ops(kobj);
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if (!ops && kobj->kset) {
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ksobj = &kobj->kset->kobj;
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if (ksobj->parent != NULL)
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ops = kobj_ns_ops(ksobj->parent);
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}
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if (ops && ops->netlink_ns && kobj->ktype->namespace) {
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const void *sock_ns, *ns;
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ns = kobj->ktype->namespace(kobj);
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sock_ns = ops->netlink_ns(dsk);
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return sock_ns != ns;
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}
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return 0;
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}
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#endif
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#ifdef CONFIG_UEVENT_HELPER
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static int kobj_usermode_filter(struct kobject *kobj)
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{
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const struct kobj_ns_type_operations *ops;
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ops = kobj_ns_ops(kobj);
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if (ops) {
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const void *init_ns, *ns;
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ns = kobj->ktype->namespace(kobj);
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init_ns = ops->initial_ns();
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return ns != init_ns;
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}
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return 0;
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}
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static int init_uevent_argv(struct kobj_uevent_env *env, const char *subsystem)
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{
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int len;
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len = strlcpy(&env->buf[env->buflen], subsystem,
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sizeof(env->buf) - env->buflen);
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if (len >= (sizeof(env->buf) - env->buflen)) {
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WARN(1, KERN_ERR "init_uevent_argv: buffer size too small\n");
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return -ENOMEM;
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}
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env->argv[0] = uevent_helper;
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env->argv[1] = &env->buf[env->buflen];
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env->argv[2] = NULL;
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env->buflen += len + 1;
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return 0;
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}
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static void cleanup_uevent_env(struct subprocess_info *info)
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{
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kfree(info->data);
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}
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#endif
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static int kobject_uevent_net_broadcast(struct kobject *kobj,
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struct kobj_uevent_env *env,
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const char *action_string,
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const char *devpath)
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{
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int retval = 0;
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#if defined(CONFIG_NET)
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struct sk_buff *skb = NULL;
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struct uevent_sock *ue_sk;
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/* send netlink message */
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list_for_each_entry(ue_sk, &uevent_sock_list, list) {
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struct sock *uevent_sock = ue_sk->sk;
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if (!netlink_has_listeners(uevent_sock, 1))
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continue;
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if (!skb) {
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/* allocate message with the maximum possible size */
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size_t len = strlen(action_string) + strlen(devpath) + 2;
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char *scratch;
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retval = -ENOMEM;
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skb = alloc_skb(len + env->buflen, GFP_KERNEL);
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if (!skb)
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continue;
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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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skb_put_data(skb, env->buf, env->buflen);
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NETLINK_CB(skb).dst_group = 1;
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}
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retval = netlink_broadcast_filtered(uevent_sock, skb_get(skb),
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0, 1, GFP_KERNEL,
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kobj_bcast_filter,
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kobj);
|
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/* ENOBUFS should be handled in userspace */
|
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if (retval == -ENOBUFS || retval == -ESRCH)
|
|
retval = 0;
|
|
}
|
|
consume_skb(skb);
|
|
#endif
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return retval;
|
|
}
|
|
|
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static void zap_modalias_env(struct kobj_uevent_env *env)
|
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{
|
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static const char modalias_prefix[] = "MODALIAS=";
|
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size_t len;
|
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int i, j;
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for (i = 0; i < env->envp_idx;) {
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if (strncmp(env->envp[i], modalias_prefix,
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sizeof(modalias_prefix) - 1)) {
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i++;
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continue;
|
|
}
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|
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len = strlen(env->envp[i]) + 1;
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|
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if (i != env->envp_idx - 1) {
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memmove(env->envp[i], env->envp[i + 1],
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env->buflen - len);
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|
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for (j = i; j < env->envp_idx - 1; j++)
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env->envp[j] = env->envp[j + 1] - len;
|
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}
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|
|
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env->envp_idx--;
|
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env->buflen -= len;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* kobject_uevent_env - send an uevent with environmental data
|
|
*
|
|
* @kobj: struct kobject that the action is happening to
|
|
* @action: action that is happening
|
|
* @envp_ext: pointer to environmental data
|
|
*
|
|
* Returns 0 if kobject_uevent_env() is completed with success or the
|
|
* corresponding error when it fails.
|
|
*/
|
|
int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
|
|
char *envp_ext[])
|
|
{
|
|
struct kobj_uevent_env *env;
|
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const char *action_string = kobject_actions[action];
|
|
const char *devpath = NULL;
|
|
const char *subsystem;
|
|
struct kobject *top_kobj;
|
|
struct kset *kset;
|
|
const struct kset_uevent_ops *uevent_ops;
|
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int i = 0;
|
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int retval = 0;
|
|
|
|
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 */
|
|
top_kobj = kobj;
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while (!top_kobj->kset && top_kobj->parent)
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top_kobj = top_kobj->parent;
|
|
|
|
if (!top_kobj->kset) {
|
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pr_debug("kobject: '%s' (%p): %s: attempted to send uevent "
|
|
"without kset!\n", kobject_name(kobj), kobj,
|
|
__func__);
|
|
return -EINVAL;
|
|
}
|
|
|
|
kset = top_kobj->kset;
|
|
uevent_ops = kset->uevent_ops;
|
|
|
|
/* skip the event, if uevent_suppress is set*/
|
|
if (kobj->uevent_suppress) {
|
|
pr_debug("kobject: '%s' (%p): %s: uevent_suppress "
|
|
"caused the event to drop!\n",
|
|
kobject_name(kobj), kobj, __func__);
|
|
return 0;
|
|
}
|
|
/* skip the event, if the filter returns zero. */
|
|
if (uevent_ops && uevent_ops->filter)
|
|
if (!uevent_ops->filter(kset, kobj)) {
|
|
pr_debug("kobject: '%s' (%p): %s: filter function "
|
|
"caused the event to drop!\n",
|
|
kobject_name(kobj), kobj, __func__);
|
|
return 0;
|
|
}
|
|
|
|
/* originating subsystem */
|
|
if (uevent_ops && uevent_ops->name)
|
|
subsystem = uevent_ops->name(kset, kobj);
|
|
else
|
|
subsystem = kobject_name(&kset->kobj);
|
|
if (!subsystem) {
|
|
pr_debug("kobject: '%s' (%p): %s: unset subsystem caused the "
|
|
"event to drop!\n", kobject_name(kobj), kobj,
|
|
__func__);
|
|
return 0;
|
|
}
|
|
|
|
/* environment buffer */
|
|
env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
|
|
if (!env)
|
|
return -ENOMEM;
|
|
|
|
/* complete object path */
|
|
devpath = kobject_get_path(kobj, GFP_KERNEL);
|
|
if (!devpath) {
|
|
retval = -ENOENT;
|
|
goto exit;
|
|
}
|
|
|
|
/* default keys */
|
|
retval = add_uevent_var(env, "ACTION=%s", action_string);
|
|
if (retval)
|
|
goto exit;
|
|
retval = add_uevent_var(env, "DEVPATH=%s", devpath);
|
|
if (retval)
|
|
goto exit;
|
|
retval = add_uevent_var(env, "SUBSYSTEM=%s", subsystem);
|
|
if (retval)
|
|
goto exit;
|
|
|
|
/* keys passed in from the caller */
|
|
if (envp_ext) {
|
|
for (i = 0; envp_ext[i]; i++) {
|
|
retval = add_uevent_var(env, "%s", envp_ext[i]);
|
|
if (retval)
|
|
goto exit;
|
|
}
|
|
}
|
|
|
|
/* let the kset specific function add its stuff */
|
|
if (uevent_ops && uevent_ops->uevent) {
|
|
retval = uevent_ops->uevent(kset, kobj, env);
|
|
if (retval) {
|
|
pr_debug("kobject: '%s' (%p): %s: uevent() returned "
|
|
"%d\n", kobject_name(kobj), kobj,
|
|
__func__, retval);
|
|
goto exit;
|
|
}
|
|
}
|
|
|
|
switch (action) {
|
|
case KOBJ_ADD:
|
|
/*
|
|
* Mark "add" event so we can make sure we deliver "remove"
|
|
* event to userspace during automatic cleanup. If
|
|
* the object did send an "add" event, "remove" will
|
|
* automatically generated by the core, if not already done
|
|
* by the caller.
|
|
*/
|
|
kobj->state_add_uevent_sent = 1;
|
|
break;
|
|
|
|
case KOBJ_REMOVE:
|
|
kobj->state_remove_uevent_sent = 1;
|
|
break;
|
|
|
|
case KOBJ_UNBIND:
|
|
zap_modalias_env(env);
|
|
break;
|
|
|
|
default:
|
|
break;
|
|
}
|
|
|
|
mutex_lock(&uevent_sock_mutex);
|
|
/* we will send an event, so request a new sequence number */
|
|
retval = add_uevent_var(env, "SEQNUM=%llu", (unsigned long long)++uevent_seqnum);
|
|
if (retval) {
|
|
mutex_unlock(&uevent_sock_mutex);
|
|
goto exit;
|
|
}
|
|
retval = kobject_uevent_net_broadcast(kobj, env, action_string,
|
|
devpath);
|
|
mutex_unlock(&uevent_sock_mutex);
|
|
|
|
#ifdef CONFIG_UEVENT_HELPER
|
|
/* call uevent_helper, usually only enabled during early boot */
|
|
if (uevent_helper[0] && !kobj_usermode_filter(kobj)) {
|
|
struct subprocess_info *info;
|
|
|
|
retval = add_uevent_var(env, "HOME=/");
|
|
if (retval)
|
|
goto exit;
|
|
retval = add_uevent_var(env,
|
|
"PATH=/sbin:/bin:/usr/sbin:/usr/bin");
|
|
if (retval)
|
|
goto exit;
|
|
retval = init_uevent_argv(env, subsystem);
|
|
if (retval)
|
|
goto exit;
|
|
|
|
retval = -ENOMEM;
|
|
info = call_usermodehelper_setup(env->argv[0], env->argv,
|
|
env->envp, GFP_KERNEL,
|
|
NULL, cleanup_uevent_env, env);
|
|
if (info) {
|
|
retval = call_usermodehelper_exec(info, UMH_NO_WAIT);
|
|
env = NULL; /* freed by cleanup_uevent_env */
|
|
}
|
|
}
|
|
#endif
|
|
|
|
exit:
|
|
kfree(devpath);
|
|
kfree(env);
|
|
return retval;
|
|
}
|
|
EXPORT_SYMBOL_GPL(kobject_uevent_env);
|
|
|
|
/**
|
|
* kobject_uevent - notify userspace by sending an uevent
|
|
*
|
|
* @kobj: struct kobject that the action is happening to
|
|
* @action: action that is happening
|
|
*
|
|
* Returns 0 if kobject_uevent() is completed with success or the
|
|
* corresponding error when it fails.
|
|
*/
|
|
int kobject_uevent(struct kobject *kobj, enum kobject_action action)
|
|
{
|
|
return kobject_uevent_env(kobj, action, NULL);
|
|
}
|
|
EXPORT_SYMBOL_GPL(kobject_uevent);
|
|
|
|
/**
|
|
* add_uevent_var - add key value string to the environment buffer
|
|
* @env: environment buffer structure
|
|
* @format: printf format for the key=value pair
|
|
*
|
|
* Returns 0 if environment variable was added successfully or -ENOMEM
|
|
* if no space was available.
|
|
*/
|
|
int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
|
|
{
|
|
va_list args;
|
|
int len;
|
|
|
|
if (env->envp_idx >= ARRAY_SIZE(env->envp)) {
|
|
WARN(1, KERN_ERR "add_uevent_var: too many keys\n");
|
|
return -ENOMEM;
|
|
}
|
|
|
|
va_start(args, format);
|
|
len = vsnprintf(&env->buf[env->buflen],
|
|
sizeof(env->buf) - env->buflen,
|
|
format, args);
|
|
va_end(args);
|
|
|
|
if (len >= (sizeof(env->buf) - env->buflen)) {
|
|
WARN(1, KERN_ERR "add_uevent_var: buffer size too small\n");
|
|
return -ENOMEM;
|
|
}
|
|
|
|
env->envp[env->envp_idx++] = &env->buf[env->buflen];
|
|
env->buflen += len + 1;
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(add_uevent_var);
|
|
|
|
#if defined(CONFIG_NET)
|
|
static int uevent_net_init(struct net *net)
|
|
{
|
|
struct uevent_sock *ue_sk;
|
|
struct netlink_kernel_cfg cfg = {
|
|
.groups = 1,
|
|
.flags = NL_CFG_F_NONROOT_RECV,
|
|
};
|
|
|
|
ue_sk = kzalloc(sizeof(*ue_sk), GFP_KERNEL);
|
|
if (!ue_sk)
|
|
return -ENOMEM;
|
|
|
|
ue_sk->sk = netlink_kernel_create(net, NETLINK_KOBJECT_UEVENT, &cfg);
|
|
if (!ue_sk->sk) {
|
|
printk(KERN_ERR
|
|
"kobject_uevent: unable to create netlink socket!\n");
|
|
kfree(ue_sk);
|
|
return -ENODEV;
|
|
}
|
|
mutex_lock(&uevent_sock_mutex);
|
|
list_add_tail(&ue_sk->list, &uevent_sock_list);
|
|
mutex_unlock(&uevent_sock_mutex);
|
|
return 0;
|
|
}
|
|
|
|
static void uevent_net_exit(struct net *net)
|
|
{
|
|
struct uevent_sock *ue_sk;
|
|
|
|
mutex_lock(&uevent_sock_mutex);
|
|
list_for_each_entry(ue_sk, &uevent_sock_list, list) {
|
|
if (sock_net(ue_sk->sk) == net)
|
|
goto found;
|
|
}
|
|
mutex_unlock(&uevent_sock_mutex);
|
|
return;
|
|
|
|
found:
|
|
list_del(&ue_sk->list);
|
|
mutex_unlock(&uevent_sock_mutex);
|
|
|
|
netlink_kernel_release(ue_sk->sk);
|
|
kfree(ue_sk);
|
|
}
|
|
|
|
static struct pernet_operations uevent_net_ops = {
|
|
.init = uevent_net_init,
|
|
.exit = uevent_net_exit,
|
|
.async = true,
|
|
};
|
|
|
|
static int __init kobject_uevent_init(void)
|
|
{
|
|
return register_pernet_subsys(&uevent_net_ops);
|
|
}
|
|
|
|
|
|
postcore_initcall(kobject_uevent_init);
|
|
#endif
|