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