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