forked from Minki/linux
4fdb3bb723
- Remove bogus code for compiling netlink as module - Add module refcounting support for modules implementing a netlink protocol - Add support for autoloading modules that implement a netlink protocol as soon as someone opens a socket for that protocol Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
371 lines
8.9 KiB
C
371 lines
8.9 KiB
C
/*
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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/socket.h>
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#include <linux/skbuff.h>
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#include <linux/netlink.h>
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#include <linux/string.h>
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#include <linux/kobject_uevent.h>
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#include <linux/kobject.h>
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#include <net/sock.h>
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#define BUFFER_SIZE 1024 /* buffer for the hotplug env */
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#define NUM_ENVP 32 /* number of env pointers */
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#if defined(CONFIG_KOBJECT_UEVENT) || defined(CONFIG_HOTPLUG)
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static char *action_to_string(enum kobject_action action)
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{
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switch (action) {
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case KOBJ_ADD:
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return "add";
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case KOBJ_REMOVE:
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return "remove";
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case KOBJ_CHANGE:
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return "change";
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case KOBJ_MOUNT:
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return "mount";
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case KOBJ_UMOUNT:
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return "umount";
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case KOBJ_OFFLINE:
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return "offline";
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case KOBJ_ONLINE:
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return "online";
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default:
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return NULL;
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}
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}
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#endif
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#ifdef CONFIG_KOBJECT_UEVENT
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static struct sock *uevent_sock;
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/**
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* send_uevent - notify userspace by sending event trough netlink socket
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*
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* @signal: signal name
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* @obj: object path (kobject)
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* @envp: possible hotplug environment to pass with the message
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* @gfp_mask:
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*/
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static int send_uevent(const char *signal, const char *obj,
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char **envp, int gfp_mask)
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{
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struct sk_buff *skb;
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char *pos;
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int len;
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if (!uevent_sock)
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return -EIO;
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len = strlen(signal) + 1;
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len += strlen(obj) + 1;
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/* allocate buffer with the maximum possible message size */
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skb = alloc_skb(len + BUFFER_SIZE, gfp_mask);
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if (!skb)
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return -ENOMEM;
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pos = skb_put(skb, len);
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sprintf(pos, "%s@%s", signal, obj);
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/* copy the environment key by key to our continuous buffer */
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if (envp) {
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int i;
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for (i = 2; envp[i]; i++) {
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len = strlen(envp[i]) + 1;
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pos = skb_put(skb, len);
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strcpy(pos, envp[i]);
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}
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}
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return netlink_broadcast(uevent_sock, skb, 0, 1, gfp_mask);
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}
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static int do_kobject_uevent(struct kobject *kobj, enum kobject_action action,
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struct attribute *attr, int gfp_mask)
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{
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char *path;
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char *attrpath;
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char *signal;
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int len;
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int rc = -ENOMEM;
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path = kobject_get_path(kobj, gfp_mask);
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if (!path)
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return -ENOMEM;
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signal = action_to_string(action);
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if (!signal)
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return -EINVAL;
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if (attr) {
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len = strlen(path);
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len += strlen(attr->name) + 2;
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attrpath = kmalloc(len, gfp_mask);
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if (!attrpath)
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goto exit;
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sprintf(attrpath, "%s/%s", path, attr->name);
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rc = send_uevent(signal, attrpath, NULL, gfp_mask);
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kfree(attrpath);
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} else
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rc = send_uevent(signal, path, NULL, gfp_mask);
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exit:
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kfree(path);
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return rc;
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}
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/**
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* kobject_uevent - notify userspace by sending event through netlink socket
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*
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* @signal: signal name
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* @kobj: struct kobject that the event is happening to
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* @attr: optional struct attribute the event belongs to
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*/
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int kobject_uevent(struct kobject *kobj, enum kobject_action action,
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struct attribute *attr)
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{
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return do_kobject_uevent(kobj, action, attr, GFP_KERNEL);
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}
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EXPORT_SYMBOL_GPL(kobject_uevent);
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int kobject_uevent_atomic(struct kobject *kobj, enum kobject_action action,
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struct attribute *attr)
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{
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return do_kobject_uevent(kobj, action, attr, GFP_ATOMIC);
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}
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EXPORT_SYMBOL_GPL(kobject_uevent_atomic);
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static int __init kobject_uevent_init(void)
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{
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uevent_sock = netlink_kernel_create(NETLINK_KOBJECT_UEVENT, NULL,
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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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return 0;
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}
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postcore_initcall(kobject_uevent_init);
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#else
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static inline int send_uevent(const char *signal, const char *obj,
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char **envp, int gfp_mask)
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{
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return 0;
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}
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#endif /* CONFIG_KOBJECT_UEVENT */
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#ifdef CONFIG_HOTPLUG
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char hotplug_path[HOTPLUG_PATH_LEN] = "/sbin/hotplug";
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u64 hotplug_seqnum;
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static DEFINE_SPINLOCK(sequence_lock);
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/**
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* kobject_hotplug - notify userspace by executing /sbin/hotplug
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*
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* @action: action that is happening (usually "ADD" or "REMOVE")
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* @kobj: struct kobject that the action is happening to
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*/
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void kobject_hotplug(struct kobject *kobj, enum kobject_action action)
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{
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char *argv [3];
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char **envp = NULL;
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char *buffer = NULL;
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char *seq_buff;
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char *scratch;
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int i = 0;
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int retval;
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char *kobj_path = NULL;
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const char *name = NULL;
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char *action_string;
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u64 seq;
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struct kobject *top_kobj = kobj;
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struct kset *kset;
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static struct kset_hotplug_ops null_hotplug_ops;
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struct kset_hotplug_ops *hotplug_ops = &null_hotplug_ops;
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/* If this kobj does not belong to a kset,
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try to find a parent that does. */
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if (!top_kobj->kset && top_kobj->parent) {
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do {
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top_kobj = top_kobj->parent;
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} while (!top_kobj->kset && top_kobj->parent);
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}
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if (top_kobj->kset)
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kset = top_kobj->kset;
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else
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return;
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if (kset->hotplug_ops)
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hotplug_ops = kset->hotplug_ops;
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/* If the kset has a filter operation, call it.
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Skip the event, if the filter returns zero. */
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if (hotplug_ops->filter) {
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if (!hotplug_ops->filter(kset, kobj))
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return;
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}
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pr_debug ("%s\n", __FUNCTION__);
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action_string = action_to_string(action);
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if (!action_string)
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return;
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envp = kmalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL);
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if (!envp)
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return;
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memset (envp, 0x00, NUM_ENVP * sizeof (char *));
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buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL);
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if (!buffer)
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goto exit;
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if (hotplug_ops->name)
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name = hotplug_ops->name(kset, kobj);
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if (name == NULL)
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name = kobject_name(&kset->kobj);
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argv [0] = hotplug_path;
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argv [1] = (char *)name; /* won't be changed but 'const' has to go */
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argv [2] = NULL;
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/* minimal command environment */
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envp [i++] = "HOME=/";
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envp [i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
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scratch = buffer;
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envp [i++] = scratch;
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scratch += sprintf(scratch, "ACTION=%s", action_string) + 1;
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kobj_path = kobject_get_path(kobj, GFP_KERNEL);
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if (!kobj_path)
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goto exit;
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envp [i++] = scratch;
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scratch += sprintf (scratch, "DEVPATH=%s", kobj_path) + 1;
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envp [i++] = scratch;
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scratch += sprintf(scratch, "SUBSYSTEM=%s", name) + 1;
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/* reserve space for the sequence,
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* put the real one in after the hotplug call */
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envp[i++] = seq_buff = scratch;
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scratch += strlen("SEQNUM=18446744073709551616") + 1;
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if (hotplug_ops->hotplug) {
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/* have the kset specific function add its stuff */
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retval = hotplug_ops->hotplug (kset, kobj,
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&envp[i], NUM_ENVP - i, scratch,
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BUFFER_SIZE - (scratch - buffer));
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if (retval) {
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pr_debug ("%s - hotplug() returned %d\n",
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__FUNCTION__, retval);
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goto exit;
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}
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}
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spin_lock(&sequence_lock);
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seq = ++hotplug_seqnum;
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spin_unlock(&sequence_lock);
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sprintf(seq_buff, "SEQNUM=%llu", (unsigned long long)seq);
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pr_debug ("%s: %s %s seq=%llu %s %s %s %s %s\n",
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__FUNCTION__, argv[0], argv[1], (unsigned long long)seq,
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envp[0], envp[1], envp[2], envp[3], envp[4]);
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send_uevent(action_string, kobj_path, envp, GFP_KERNEL);
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if (!hotplug_path[0])
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goto exit;
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retval = call_usermodehelper (argv[0], argv, envp, 0);
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if (retval)
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pr_debug ("%s - call_usermodehelper returned %d\n",
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__FUNCTION__, retval);
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exit:
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kfree(kobj_path);
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kfree(buffer);
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kfree(envp);
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return;
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}
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EXPORT_SYMBOL(kobject_hotplug);
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/**
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* add_hotplug_env_var - helper for creating hotplug environment variables
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* @envp: Pointer to table of environment variables, as passed into
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* hotplug() method.
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* @num_envp: Number of environment variable slots available, as
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* passed into hotplug() method.
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* @cur_index: Pointer to current index into @envp. It should be
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* initialized to 0 before the first call to add_hotplug_env_var(),
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* and will be incremented on success.
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* @buffer: Pointer to buffer for environment variables, as passed
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* into hotplug() method.
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* @buffer_size: Length of @buffer, as passed into hotplug() method.
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* @cur_len: Pointer to current length of space used in @buffer.
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* Should be initialized to 0 before the first call to
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* add_hotplug_env_var(), and will be incremented on success.
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* @format: Format for creating environment variable (of the form
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* "XXX=%x") for snprintf().
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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_hotplug_env_var(char **envp, int num_envp, int *cur_index,
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char *buffer, int buffer_size, int *cur_len,
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const char *format, ...)
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{
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va_list args;
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/*
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* We check against num_envp - 1 to make sure there is at
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* least one slot left after we return, since the hotplug
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* method needs to set the last slot to NULL.
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*/
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if (*cur_index >= num_envp - 1)
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return -ENOMEM;
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envp[*cur_index] = buffer + *cur_len;
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va_start(args, format);
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*cur_len += vsnprintf(envp[*cur_index],
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max(buffer_size - *cur_len, 0),
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format, args) + 1;
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va_end(args);
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if (*cur_len > buffer_size)
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return -ENOMEM;
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(*cur_index)++;
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return 0;
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}
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EXPORT_SYMBOL(add_hotplug_env_var);
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#endif /* CONFIG_HOTPLUG */
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