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