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 <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
  21 ACPI_MODULE_NAME("event");
  22
  23 #ifdef CONFIG_ACPI_PROC_EVENT
  24 /* Global vars for handling event proc entry */
  25 static DEFINE_SPINLOCK(acpi_system_event_lock);
  26 int event_is_open = 0;
  27 extern struct list_head acpi_bus_event_list;
  28 extern wait_queue_head_t acpi_bus_event_queue;
  29
  30 static 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
  47 static ssize_t
  48 acpi_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
  91 static 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
  99 static 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
 107 static 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 };
 114 #endif  /* CONFIG_ACPI_PROC_EVENT */
 115
 116 /* ACPI notifier chain */
 117 static BLOCKING_NOTIFIER_HEAD(acpi_chain_head);
 118
 119 int acpi_notifier_call_chain(struct acpi_device *dev, u32 type, u32 data)
 120 {
 121         struct acpi_bus_event event;
 122
 123         strcpy(event.device_class, dev->pnp.device_class);
 124         strcpy(event.bus_id, dev->pnp.bus_id);
 125         event.type = type;
 126         event.data = data;
 127         return (blocking_notifier_call_chain(&acpi_chain_head, 0, (void *)&event)
 128                         == NOTIFY_BAD) ? -EINVAL : 0;
 129 }
 130 EXPORT_SYMBOL(acpi_notifier_call_chain);
 131
 132 int register_acpi_notifier(struct notifier_block *nb)
 133 {
 134         return blocking_notifier_chain_register(&acpi_chain_head, nb);
 135 }
 136 EXPORT_SYMBOL(register_acpi_notifier);
 137
 138 int unregister_acpi_notifier(struct notifier_block *nb)
 139 {
 140         return blocking_notifier_chain_unregister(&acpi_chain_head, nb);
 141 }
 142 EXPORT_SYMBOL(unregister_acpi_notifier);
 143
 144 #ifdef CONFIG_NET
 145 static unsigned int acpi_event_seqnum;
 146 struct acpi_genl_event {
 147         acpi_device_class device_class;
 148         char bus_id[15];
 149         u32 type;
 150         u32 data;
 151 };
 152
 153 /* attributes of acpi_genl_family */
 154 enum {
 155         ACPI_GENL_ATTR_UNSPEC,
 156         ACPI_GENL_ATTR_EVENT,   /* ACPI event info needed by user space */
 157         __ACPI_GENL_ATTR_MAX,
 158 };
 159 #define ACPI_GENL_ATTR_MAX (__ACPI_GENL_ATTR_MAX - 1)
 160
 161 /* commands supported by the acpi_genl_family */
 162 enum {
 163         ACPI_GENL_CMD_UNSPEC,
 164         ACPI_GENL_CMD_EVENT,    /* kernel->user notifications for ACPI events */
 165         __ACPI_GENL_CMD_MAX,
 166 };
 167 #define ACPI_GENL_CMD_MAX (__ACPI_GENL_CMD_MAX - 1)
 168
 169 #define ACPI_GENL_FAMILY_NAME           "acpi_event"
 170 #define ACPI_GENL_VERSION               0x01
 171 #define ACPI_GENL_MCAST_GROUP_NAME      "acpi_mc_group"
 172
 173 static struct genl_family acpi_event_genl_family = {
 174         .id = GENL_ID_GENERATE,
 175         .name = ACPI_GENL_FAMILY_NAME,
 176         .version = ACPI_GENL_VERSION,
 177         .maxattr = ACPI_GENL_ATTR_MAX,
 178 };
 179
 180 static struct genl_multicast_group acpi_event_mcgrp = {
 181         .name = ACPI_GENL_MCAST_GROUP_NAME,
 182 };
 183
 184 int acpi_bus_generate_netlink_event(const char *device_class,
 185                                       const char *bus_id,
 186                                       u8 type, int data)
 187 {
 188         struct sk_buff *skb;
 189         struct nlattr *attr;
 190         struct acpi_genl_event *event;
 191         void *msg_header;
 192         int size;
 193         int result;
 194
 195         /* allocate memory */
 196         size = nla_total_size(sizeof(struct acpi_genl_event)) +
 197             nla_total_size(0);
 198
 199         skb = genlmsg_new(size, GFP_ATOMIC);
 200         if (!skb)
 201                 return -ENOMEM;
 202
 203         /* add the genetlink message header */
 204         msg_header = genlmsg_put(skb, 0, acpi_event_seqnum++,
 205                                  &acpi_event_genl_family, 0,
 206                                  ACPI_GENL_CMD_EVENT);
 207         if (!msg_header) {
 208                 nlmsg_free(skb);
 209                 return -ENOMEM;
 210         }
 211
 212         /* fill the data */
 213         attr =
 214             nla_reserve(skb, ACPI_GENL_ATTR_EVENT,
 215                         sizeof(struct acpi_genl_event));
 216         if (!attr) {
 217                 nlmsg_free(skb);
 218                 return -EINVAL;
 219         }
 220
 221         event = nla_data(attr);
 222         if (!event) {
 223                 nlmsg_free(skb);
 224                 return -EINVAL;
 225         }
 226
 227         memset(event, 0, sizeof(struct acpi_genl_event));
 228
 229         strcpy(event->device_class, device_class);
 230         strcpy(event->bus_id, bus_id);
 231         event->type = type;
 232         event->data = data;
 233
 234         /* send multicast genetlink message */
 235         result = genlmsg_end(skb, msg_header);
 236         if (result < 0) {
 237                 nlmsg_free(skb);
 238                 return result;
 239         }
 240
 241         genlmsg_multicast(skb, 0, acpi_event_mcgrp.id, GFP_ATOMIC);
 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 = proc_create("event", S_IRUSR, acpi_root_dir,
 298                             &acpi_system_event_ops);
 299         if (!entry)
 300                 return -ENODEV;
 301 #endif
 302
 303         return 0;
 304 }
 305
 306 fs_initcall(acpi_event_init);