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         .llseek = default_llseek,
 114 };
 115 #endif  /* CONFIG_ACPI_PROC_EVENT */
 116
 117 /* ACPI notifier chain */
 118 static BLOCKING_NOTIFIER_HEAD(acpi_chain_head);
 119
 120 int 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 }
 131 EXPORT_SYMBOL(acpi_notifier_call_chain);
 132
 133 int register_acpi_notifier(struct notifier_block *nb)
 134 {
 135         return blocking_notifier_chain_register(&acpi_chain_head, nb);
 136 }
 137 EXPORT_SYMBOL(register_acpi_notifier);
 138
 139 int unregister_acpi_notifier(struct notifier_block *nb)
 140 {
 141         return blocking_notifier_chain_unregister(&acpi_chain_head, nb);
 142 }
 143 EXPORT_SYMBOL(unregister_acpi_notifier);
 144
 145 #ifdef CONFIG_NET
 146 static unsigned int acpi_event_seqnum;
 147 struct 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 */
 155 enum {
 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 */
 163 enum {
 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
 174 static 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
 181 static struct genl_multicast_group acpi_event_mcgrp = {
 182         .name = ACPI_GENL_MCAST_GROUP_NAME,
 183 };
 184
 185 int 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
 246 EXPORT_SYMBOL(acpi_bus_generate_netlink_event);
 247
 248 static 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
 265 int 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
 272 EXPORT_SYMBOL(acpi_bus_generate_netlink_event);
 273
 274 static int acpi_event_genetlink_init(void)
 275 {
 276         return -ENODEV;
 277 }
 278 #endif
 279
 280 static 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
 307 fs_initcall(acpi_event_init);