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