drivers/acpi/event.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * event.c - exporting ACPI events via procfs
   4  *
   5  *  Copyright (C) 2001, 2002 Andy Grover <[email protected]>
   6  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <[email protected]>
   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 */
  23 static BLOCKING_NOTIFIER_HEAD(acpi_chain_head);
  24
  25 int 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 }
  36 EXPORT_SYMBOL(acpi_notifier_call_chain);
  37
  38 int register_acpi_notifier(struct notifier_block *nb)
  39 {
  40         return blocking_notifier_chain_register(&acpi_chain_head, nb);
  41 }
  42 EXPORT_SYMBOL(register_acpi_notifier);
  43
  44 int unregister_acpi_notifier(struct notifier_block *nb)
  45 {
  46         return blocking_notifier_chain_unregister(&acpi_chain_head, nb);
  47 }
  48 EXPORT_SYMBOL(unregister_acpi_notifier);
  49
  50 #ifdef CONFIG_NET
  51 static unsigned int acpi_event_seqnum;
  52 struct 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 */
  60 enum {
  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 */
  68 enum {
  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
  79 static const struct genl_multicast_group acpi_event_mcgrps[] = {
  80         { .name = ACPI_GENL_MCAST_GROUP_NAME, },
  81 };
  82
  83 static 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
  92 int 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
 143 EXPORT_SYMBOL(acpi_bus_generate_netlink_event);
 144
 145 static int __init acpi_event_genetlink_init(void)
 146 {
 147         return genl_register_family(&acpi_event_genl_family);
 148 }
 149
 150 #else
 151 int 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
 158 EXPORT_SYMBOL(acpi_bus_generate_netlink_event);
 159
 160 static int acpi_event_genetlink_init(void)
 161 {
 162         return -ENODEV;
 163 }
 164 #endif
 165
 166 static 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
 181 fs_initcall(acpi_event_init);