linux/drivers/acpi/event.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * event.c - exporting ACPI events via procfs
   4 *
   5 *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
   6 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
   7 *
   8 */
   9
  10#include <linux/spinlock.h>
  11#include <linux/export.h>
  12#include <linux/proc_fs.h>
  13#include <linux/init.h>
  14#include <linux/poll.h>
  15#include <linux/gfp.h>
  16#include <linux/acpi.h>
  17#include <net/netlink.h>
  18#include <net/genetlink.h>
  19
  20#include "internal.h"
  21
  22/* ACPI notifier chain */
  23static BLOCKING_NOTIFIER_HEAD(acpi_chain_head);
  24
  25int acpi_notifier_call_chain(struct acpi_device *dev, u32 type, u32 data)
  26{
  27        struct acpi_bus_event event;
  28
  29        strcpy(event.device_class, dev->pnp.device_class);
  30        strcpy(event.bus_id, dev->pnp.bus_id);
  31        event.type = type;
  32        event.data = data;
  33        return (blocking_notifier_call_chain(&acpi_chain_head, 0, (void *)&event)
  34                        == NOTIFY_BAD) ? -EINVAL : 0;
  35}
  36EXPORT_SYMBOL(acpi_notifier_call_chain);
  37
  38int register_acpi_notifier(struct notifier_block *nb)
  39{
  40        return blocking_notifier_chain_register(&acpi_chain_head, nb);
  41}
  42EXPORT_SYMBOL(register_acpi_notifier);
  43
  44int unregister_acpi_notifier(struct notifier_block *nb)
  45{
  46        return blocking_notifier_chain_unregister(&acpi_chain_head, nb);
  47}
  48EXPORT_SYMBOL(unregister_acpi_notifier);
  49
  50#ifdef CONFIG_NET
  51static unsigned int acpi_event_seqnum;
  52struct acpi_genl_event {
  53        acpi_device_class device_class;
  54        char bus_id[15];
  55        u32 type;
  56        u32 data;
  57};
  58
  59/* attributes of acpi_genl_family */
  60enum {
  61        ACPI_GENL_ATTR_UNSPEC,
  62        ACPI_GENL_ATTR_EVENT,   /* ACPI event info needed by user space */
  63        __ACPI_GENL_ATTR_MAX,
  64};
  65#define ACPI_GENL_ATTR_MAX (__ACPI_GENL_ATTR_MAX - 1)
  66
  67/* commands supported by the acpi_genl_family */
  68enum {
  69        ACPI_GENL_CMD_UNSPEC,
  70        ACPI_GENL_CMD_EVENT,    /* kernel->user notifications for ACPI events */
  71        __ACPI_GENL_CMD_MAX,
  72};
  73#define ACPI_GENL_CMD_MAX (__ACPI_GENL_CMD_MAX - 1)
  74
  75#define ACPI_GENL_FAMILY_NAME           "acpi_event"
  76#define ACPI_GENL_VERSION               0x01
  77#define ACPI_GENL_MCAST_GROUP_NAME      "acpi_mc_group"
  78
  79static const struct genl_multicast_group acpi_event_mcgrps[] = {
  80        { .name = ACPI_GENL_MCAST_GROUP_NAME, },
  81};
  82
  83static struct genl_family acpi_event_genl_family __ro_after_init = {
  84        .module = THIS_MODULE,
  85        .name = ACPI_GENL_FAMILY_NAME,
  86        .version = ACPI_GENL_VERSION,
  87        .maxattr = ACPI_GENL_ATTR_MAX,
  88        .mcgrps = acpi_event_mcgrps,
  89        .n_mcgrps = ARRAY_SIZE(acpi_event_mcgrps),
  90};
  91
  92int acpi_bus_generate_netlink_event(const char *device_class,
  93                                      const char *bus_id,
  94                                      u8 type, int data)
  95{
  96        struct sk_buff *skb;
  97        struct nlattr *attr;
  98        struct acpi_genl_event *event;
  99        void *msg_header;
 100        int size;
 101
 102        /* allocate memory */
 103        size = nla_total_size(sizeof(struct acpi_genl_event)) +
 104            nla_total_size(0);
 105
 106        skb = genlmsg_new(size, GFP_ATOMIC);
 107        if (!skb)
 108                return -ENOMEM;
 109
 110        /* add the genetlink message header */
 111        msg_header = genlmsg_put(skb, 0, acpi_event_seqnum++,
 112                                 &acpi_event_genl_family, 0,
 113                                 ACPI_GENL_CMD_EVENT);
 114        if (!msg_header) {
 115                nlmsg_free(skb);
 116                return -ENOMEM;
 117        }
 118
 119        /* fill the data */
 120        attr =
 121            nla_reserve(skb, ACPI_GENL_ATTR_EVENT,
 122                        sizeof(struct acpi_genl_event));
 123        if (!attr) {
 124                nlmsg_free(skb);
 125                return -EINVAL;
 126        }
 127
 128        event = nla_data(attr);
 129        memset(event, 0, sizeof(struct acpi_genl_event));
 130
 131        strscpy(event->device_class, device_class, sizeof(event->device_class));
 132        strscpy(event->bus_id, bus_id, sizeof(event->bus_id));
 133        event->type = type;
 134        event->data = data;
 135
 136        /* send multicast genetlink message */
 137        genlmsg_end(skb, msg_header);
 138
 139        genlmsg_multicast(&acpi_event_genl_family, skb, 0, 0, GFP_ATOMIC);
 140        return 0;
 141}
 142
 143EXPORT_SYMBOL(acpi_bus_generate_netlink_event);
 144
 145static int __init acpi_event_genetlink_init(void)
 146{
 147        return genl_register_family(&acpi_event_genl_family);
 148}
 149
 150#else
 151int acpi_bus_generate_netlink_event(const char *device_class,
 152                                      const char *bus_id,
 153                                      u8 type, int data)
 154{
 155        return 0;
 156}
 157
 158EXPORT_SYMBOL(acpi_bus_generate_netlink_event);
 159
 160static int acpi_event_genetlink_init(void)
 161{
 162        return -ENODEV;
 163}
 164#endif
 165
 166static int __init acpi_event_init(void)
 167{
 168        int error = 0;
 169
 170        if (acpi_disabled)
 171                return 0;
 172
 173        /* create genetlink for acpi event */
 174        error = acpi_event_genetlink_init();
 175        if (error)
 176                printk(KERN_WARNING PREFIX
 177                       "Failed to create genetlink family for ACPI event\n");
 178        return 0;
 179}
 180
 181fs_initcall(acpi_event_init);
 182