linux/drivers/acpi/event.c
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   1/*
   2 * event.c - exporting ACPI events via procfs
   3 *
   4 *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
   5 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
   6 *
   7 */
   8
   9#include <linux/spinlock.h>
  10#include <linux/proc_fs.h>
  11#include <linux/init.h>
  12#include <linux/poll.h>
  13#include <linux/gfp.h>
  14#include <acpi/acpi_drivers.h>
  15#include <net/netlink.h>
  16#include <net/genetlink.h>
  17
  18#include "internal.h"
  19
  20#define _COMPONENT              ACPI_SYSTEM_COMPONENT
  21ACPI_MODULE_NAME("event");
  22
  23#ifdef CONFIG_ACPI_PROC_EVENT
  24/* Global vars for handling event proc entry */
  25static DEFINE_SPINLOCK(acpi_system_event_lock);
  26int event_is_open = 0;
  27extern struct list_head acpi_bus_event_list;
  28extern wait_queue_head_t acpi_bus_event_queue;
  29
  30static int acpi_system_open_event(struct inode *inode, struct file *file)
  31{
  32        spin_lock_irq(&acpi_system_event_lock);
  33
  34        if (event_is_open)
  35                goto out_busy;
  36
  37        event_is_open = 1;
  38
  39        spin_unlock_irq(&acpi_system_event_lock);
  40        return 0;
  41
  42      out_busy:
  43        spin_unlock_irq(&acpi_system_event_lock);
  44        return -EBUSY;
  45}
  46
  47static ssize_t
  48acpi_system_read_event(struct file *file, char __user * buffer, size_t count,
  49                       loff_t * ppos)
  50{
  51        int result = 0;
  52        struct acpi_bus_event event;
  53        static char str[ACPI_MAX_STRING];
  54        static int chars_remaining = 0;
  55        static char *ptr;
  56
  57        if (!chars_remaining) {
  58                memset(&event, 0, sizeof(struct acpi_bus_event));
  59
  60                if ((file->f_flags & O_NONBLOCK)
  61                    && (list_empty(&acpi_bus_event_list)))
  62                        return -EAGAIN;
  63
  64                result = acpi_bus_receive_event(&event);
  65                if (result)
  66                        return result;
  67
  68                chars_remaining = sprintf(str, "%s %s %08x %08x\n",
  69                                          event.device_class ? event.
  70                                          device_class : "<unknown>",
  71                                          event.bus_id ? event.
  72                                          bus_id : "<unknown>", event.type,
  73                                          event.data);
  74                ptr = str;
  75        }
  76
  77        if (chars_remaining < count) {
  78                count = chars_remaining;
  79        }
  80
  81        if (copy_to_user(buffer, ptr, count))
  82                return -EFAULT;
  83
  84        *ppos += count;
  85        chars_remaining -= count;
  86        ptr += count;
  87
  88        return count;
  89}
  90
  91static int acpi_system_close_event(struct inode *inode, struct file *file)
  92{
  93        spin_lock_irq(&acpi_system_event_lock);
  94        event_is_open = 0;
  95        spin_unlock_irq(&acpi_system_event_lock);
  96        return 0;
  97}
  98
  99static unsigned int acpi_system_poll_event(struct file *file, poll_table * wait)
 100{
 101        poll_wait(file, &acpi_bus_event_queue, wait);
 102        if (!list_empty(&acpi_bus_event_list))
 103                return POLLIN | POLLRDNORM;
 104        return 0;
 105}
 106
 107static const struct file_operations acpi_system_event_ops = {
 108        .owner = THIS_MODULE,
 109        .open = acpi_system_open_event,
 110        .read = acpi_system_read_event,
 111        .release = acpi_system_close_event,
 112        .poll = acpi_system_poll_event,
 113        .llseek = default_llseek,
 114};
 115#endif  /* CONFIG_ACPI_PROC_EVENT */
 116
 117/* ACPI notifier chain */
 118static BLOCKING_NOTIFIER_HEAD(acpi_chain_head);
 119
 120int acpi_notifier_call_chain(struct acpi_device *dev, u32 type, u32 data)
 121{
 122        struct acpi_bus_event event;
 123
 124        strcpy(event.device_class, dev->pnp.device_class);
 125        strcpy(event.bus_id, dev->pnp.bus_id);
 126        event.type = type;
 127        event.data = data;
 128        return (blocking_notifier_call_chain(&acpi_chain_head, 0, (void *)&event)
 129                        == NOTIFY_BAD) ? -EINVAL : 0;
 130}
 131EXPORT_SYMBOL(acpi_notifier_call_chain);
 132
 133int register_acpi_notifier(struct notifier_block *nb)
 134{
 135        return blocking_notifier_chain_register(&acpi_chain_head, nb);
 136}
 137EXPORT_SYMBOL(register_acpi_notifier);
 138
 139int unregister_acpi_notifier(struct notifier_block *nb)
 140{
 141        return blocking_notifier_chain_unregister(&acpi_chain_head, nb);
 142}
 143EXPORT_SYMBOL(unregister_acpi_notifier);
 144
 145#ifdef CONFIG_NET
 146static unsigned int acpi_event_seqnum;
 147struct acpi_genl_event {
 148        acpi_device_class device_class;
 149        char bus_id[15];
 150        u32 type;
 151        u32 data;
 152};
 153
 154/* attributes of acpi_genl_family */
 155enum {
 156        ACPI_GENL_ATTR_UNSPEC,
 157        ACPI_GENL_ATTR_EVENT,   /* ACPI event info needed by user space */
 158        __ACPI_GENL_ATTR_MAX,
 159};
 160#define ACPI_GENL_ATTR_MAX (__ACPI_GENL_ATTR_MAX - 1)
 161
 162/* commands supported by the acpi_genl_family */
 163enum {
 164        ACPI_GENL_CMD_UNSPEC,
 165        ACPI_GENL_CMD_EVENT,    /* kernel->user notifications for ACPI events */
 166        __ACPI_GENL_CMD_MAX,
 167};
 168#define ACPI_GENL_CMD_MAX (__ACPI_GENL_CMD_MAX - 1)
 169
 170#define ACPI_GENL_FAMILY_NAME           "acpi_event"
 171#define ACPI_GENL_VERSION               0x01
 172#define ACPI_GENL_MCAST_GROUP_NAME      "acpi_mc_group"
 173
 174static struct genl_family acpi_event_genl_family = {
 175        .id = GENL_ID_GENERATE,
 176        .name = ACPI_GENL_FAMILY_NAME,
 177        .version = ACPI_GENL_VERSION,
 178        .maxattr = ACPI_GENL_ATTR_MAX,
 179};
 180
 181static struct genl_multicast_group acpi_event_mcgrp = {
 182        .name = ACPI_GENL_MCAST_GROUP_NAME,
 183};
 184
 185int acpi_bus_generate_netlink_event(const char *device_class,
 186                                      const char *bus_id,
 187                                      u8 type, int data)
 188{
 189        struct sk_buff *skb;
 190        struct nlattr *attr;
 191        struct acpi_genl_event *event;
 192        void *msg_header;
 193        int size;
 194        int result;
 195
 196        /* allocate memory */
 197        size = nla_total_size(sizeof(struct acpi_genl_event)) +
 198            nla_total_size(0);
 199
 200        skb = genlmsg_new(size, GFP_ATOMIC);
 201        if (!skb)
 202                return -ENOMEM;
 203
 204        /* add the genetlink message header */
 205        msg_header = genlmsg_put(skb, 0, acpi_event_seqnum++,
 206                                 &acpi_event_genl_family, 0,
 207                                 ACPI_GENL_CMD_EVENT);
 208        if (!msg_header) {
 209                nlmsg_free(skb);
 210                return -ENOMEM;
 211        }
 212
 213        /* fill the data */
 214        attr =
 215            nla_reserve(skb, ACPI_GENL_ATTR_EVENT,
 216                        sizeof(struct acpi_genl_event));
 217        if (!attr) {
 218                nlmsg_free(skb);
 219                return -EINVAL;
 220        }
 221
 222        event = nla_data(attr);
 223        if (!event) {
 224                nlmsg_free(skb);
 225                return -EINVAL;
 226        }
 227
 228        memset(event, 0, sizeof(struct acpi_genl_event));
 229
 230        strcpy(event->device_class, device_class);
 231        strcpy(event->bus_id, bus_id);
 232        event->type = type;
 233        event->data = data;
 234
 235        /* send multicast genetlink message */
 236        result = genlmsg_end(skb, msg_header);
 237        if (result < 0) {
 238                nlmsg_free(skb);
 239                return result;
 240        }
 241
 242        genlmsg_multicast(skb, 0, acpi_event_mcgrp.id, GFP_ATOMIC);
 243        return 0;
 244}
 245
 246EXPORT_SYMBOL(acpi_bus_generate_netlink_event);
 247
 248static int acpi_event_genetlink_init(void)
 249{
 250        int result;
 251
 252        result = genl_register_family(&acpi_event_genl_family);
 253        if (result)
 254                return result;
 255
 256        result = genl_register_mc_group(&acpi_event_genl_family,
 257                                        &acpi_event_mcgrp);
 258        if (result)
 259                genl_unregister_family(&acpi_event_genl_family);
 260
 261        return result;
 262}
 263
 264#else
 265int acpi_bus_generate_netlink_event(const char *device_class,
 266                                      const char *bus_id,
 267                                      u8 type, int data)
 268{
 269        return 0;
 270}
 271
 272EXPORT_SYMBOL(acpi_bus_generate_netlink_event);
 273
 274static int acpi_event_genetlink_init(void)
 275{
 276        return -ENODEV;
 277}
 278#endif
 279
 280static int __init acpi_event_init(void)
 281{
 282#ifdef CONFIG_ACPI_PROC_EVENT
 283        struct proc_dir_entry *entry;
 284#endif
 285        int error = 0;
 286
 287        if (acpi_disabled)
 288                return 0;
 289
 290        /* create genetlink for acpi event */
 291        error = acpi_event_genetlink_init();
 292        if (error)
 293                printk(KERN_WARNING PREFIX
 294                       "Failed to create genetlink family for ACPI event\n");
 295
 296#ifdef CONFIG_ACPI_PROC_EVENT
 297        /* 'event' [R] */
 298        entry = proc_create("event", S_IRUSR, acpi_root_dir,
 299                            &acpi_system_event_ops);
 300        if (!entry)
 301                return -ENODEV;
 302#endif
 303
 304        return 0;
 305}
 306
 307fs_initcall(acpi_event_init);
 308