drivers/acpi/event.c

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