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