release/src-rt/linux/linux-2.6/lib/kobject_uevent.c

   1 /*
   2  * kernel userspace event delivery
   3  *
   4  * Copyright (C) 2004 Red Hat, Inc.  All rights reserved.
   5  * Copyright (C) 2004 Novell, Inc.  All rights reserved.
   6  * Copyright (C) 2004 IBM, Inc. All rights reserved.
   7  *
   8  * Licensed under the GNU GPL v2.
   9  *
  10  * Authors:
  11  *      Robert Love             <rml@novell.com>
  12  *      Kay Sievers             <kay.sievers@vrfy.org>
  13  *      Arjan van de Ven        <arjanv@redhat.com>
  14  *      Greg Kroah-Hartman      <greg@kroah.com>
  15  */
  16
  17 #include <linux/spinlock.h>
  18 #include <linux/socket.h>
  19 #include <linux/skbuff.h>
  20 #include <linux/netlink.h>
  21 #include <linux/string.h>
  22 #include <linux/kobject.h>
  23 #include <net/sock.h>
  24
  25 #define BUFFER_SIZE     2048    /* buffer for the variables */
  26 #define NUM_ENVP        32      /* number of env pointers */
  27
  28 #if defined(CONFIG_HOTPLUG)
  29 u64 uevent_seqnum;
  30 char uevent_helper[UEVENT_HELPER_PATH_LEN] = "/sbin/hotplug";
  31 static DEFINE_SPINLOCK(sequence_lock);
  32 #if defined(CONFIG_NET)
  33 struct sock *uevent_sock = NULL;
  34 EXPORT_SYMBOL_GPL(uevent_sock);
  35 #endif
  36
  37 u64 uevent_next_seqnum(void)
  38 {
  39         u64 seq;
  40
  41         spin_lock(&sequence_lock);
  42         seq = ++uevent_seqnum;
  43         spin_unlock(&sequence_lock);
  44
  45         return seq;
  46 }
  47 EXPORT_SYMBOL_GPL(uevent_next_seqnum);
  48
  49 static char *action_to_string(enum kobject_action action)
  50 {
  51         switch (action) {
  52         case KOBJ_ADD:
  53                 return "add";
  54         case KOBJ_REMOVE:
  55                 return "remove";
  56         case KOBJ_CHANGE:
  57                 return "change";
  58         case KOBJ_OFFLINE:
  59                 return "offline";
  60         case KOBJ_ONLINE:
  61                 return "online";
  62         case KOBJ_MOVE:
  63                 return "move";
  64         default:
  65                 return NULL;
  66         }
  67 }
  68
  69 /**
  70  * kobject_uevent_env - send an uevent with environmental data
  71  *
  72  * @action: action that is happening (usually KOBJ_MOVE)
  73  * @kobj: struct kobject that the action is happening to
  74  * @envp_ext: pointer to environmental data
  75  *
  76  * Returns 0 if kobject_uevent() is completed with success or the
  77  * corresponding error when it fails.
  78  */
  79 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
  80                         char *envp_ext[])
  81 {
  82         char **envp;
  83         char *buffer;
  84         char *scratch;
  85         const char *action_string;
  86         const char *devpath = NULL;
  87         const char *subsystem;
  88         struct kobject *top_kobj;
  89         struct kset *kset;
  90         struct kset_uevent_ops *uevent_ops;
  91         u64 seq;
  92         char *seq_buff;
  93         int i = 0;
  94         int retval = 0;
  95         int j;
  96
  97         pr_debug("%s\n", __FUNCTION__);
  98
  99         action_string = action_to_string(action);
 100         if (!action_string) {
 101                 pr_debug("kobject attempted to send uevent without action_string!\n");
 102                 return -EINVAL;
 103         }
 104
 105         /* search the kset we belong to */
 106         top_kobj = kobj;
 107         while (!top_kobj->kset && top_kobj->parent) {
 108                 top_kobj = top_kobj->parent;
 109         }
 110         if (!top_kobj->kset) {
 111                 pr_debug("kobject attempted to send uevent without kset!\n");
 112                 return -EINVAL;
 113         }
 114
 115         kset = top_kobj->kset;
 116         uevent_ops = kset->uevent_ops;
 117
 118         /*  skip the event, if the filter returns zero. */
 119         if (uevent_ops && uevent_ops->filter)
 120                 if (!uevent_ops->filter(kset, kobj)) {
 121                         pr_debug("kobject filter function caused the event to drop!\n");
 122                         return 0;
 123                 }
 124
 125         /* originating subsystem */
 126         if (uevent_ops && uevent_ops->name)
 127                 subsystem = uevent_ops->name(kset, kobj);
 128         else
 129                 subsystem = kobject_name(&kset->kobj);
 130         if (!subsystem) {
 131                 pr_debug("unset subsytem caused the event to drop!\n");
 132                 return 0;
 133         }
 134
 135         /* environment index */
 136         envp = kzalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL);
 137         if (!envp)
 138                 return -ENOMEM;
 139
 140         /* environment values */
 141         buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL);
 142         if (!buffer) {
 143                 retval = -ENOMEM;
 144                 goto exit;
 145         }
 146
 147         /* complete object path */
 148         devpath = kobject_get_path(kobj, GFP_KERNEL);
 149         if (!devpath) {
 150                 retval = -ENOENT;
 151                 goto exit;
 152         }
 153
 154         /* event environemnt for helper process only */
 155         envp[i++] = "HOME=/";
 156         envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
 157
 158         /* default keys */
 159         scratch = buffer;
 160         envp [i++] = scratch;
 161         scratch += sprintf(scratch, "ACTION=%s", action_string) + 1;
 162         envp [i++] = scratch;
 163         scratch += sprintf (scratch, "DEVPATH=%s", devpath) + 1;
 164         envp [i++] = scratch;
 165         scratch += sprintf(scratch, "SUBSYSTEM=%s", subsystem) + 1;
 166         for (j = 0; envp_ext && envp_ext[j]; j++)
 167                 envp[i++] = envp_ext[j];
 168         /* just reserve the space, overwrite it after kset call has returned */
 169         envp[i++] = seq_buff = scratch;
 170         scratch += strlen("SEQNUM=18446744073709551616") + 1;
 171
 172         /* let the kset specific function add its stuff */
 173         if (uevent_ops && uevent_ops->uevent) {
 174                 retval = uevent_ops->uevent(kset, kobj,
 175                                   &envp[i], NUM_ENVP - i, scratch,
 176                                   BUFFER_SIZE - (scratch - buffer));
 177                 if (retval) {
 178                         pr_debug ("%s - uevent() returned %d\n",
 179                                   __FUNCTION__, retval);
 180                         goto exit;
 181                 }
 182         }
 183
 184         /* we will send an event, request a new sequence number */
 185         seq = uevent_next_seqnum();
 186         sprintf(seq_buff, "SEQNUM=%llu", (unsigned long long)seq);
 187
 188 #if defined(CONFIG_NET)
 189         /* send netlink message */
 190         if (uevent_sock) {
 191                 struct sk_buff *skb;
 192                 size_t len;
 193
 194                 /* allocate message with the maximum possible size */
 195                 len = strlen(action_string) + strlen(devpath) + 2;
 196                 skb = alloc_skb(len + BUFFER_SIZE, GFP_KERNEL);
 197                 if (skb) {
 198                         /* add header */
 199                         scratch = skb_put(skb, len);
 200                         sprintf(scratch, "%s@%s", action_string, devpath);
 201
 202                         /* copy keys to our continuous event payload buffer */
 203                         for (i = 2; envp[i]; i++) {
 204                                 len = strlen(envp[i]) + 1;
 205                                 scratch = skb_put(skb, len);
 206                                 strcpy(scratch, envp[i]);
 207                         }
 208
 209                         NETLINK_CB(skb).dst_group = 1;
 210                         netlink_broadcast(uevent_sock, skb, 0, 1, GFP_KERNEL);
 211                 }
 212         }
 213 #endif
 214
 215         /* call uevent_helper, usually only enabled during early boot */
 216         if (uevent_helper[0]) {
 217                 char *argv [3];
 218
 219                 argv [0] = uevent_helper;
 220                 argv [1] = (char *)subsystem;
 221                 argv [2] = NULL;
 222                 call_usermodehelper (argv[0], argv, envp, 0);
 223         }
 224
 225 exit:
 226         kfree(devpath);
 227         kfree(buffer);
 228         kfree(envp);
 229         return retval;
 230 }
 231
 232 EXPORT_SYMBOL_GPL(kobject_uevent_env);
 233
 234 /**
 235  * kobject_uevent - notify userspace by ending an uevent
 236  *
 237  * @action: action that is happening (usually KOBJ_ADD and KOBJ_REMOVE)
 238  * @kobj: struct kobject that the action is happening to
 239  *
 240  * Returns 0 if kobject_uevent() is completed with success or the
 241  * corresponding error when it fails.
 242  */
 243 int kobject_uevent(struct kobject *kobj, enum kobject_action action)
 244 {
 245         return kobject_uevent_env(kobj, action, NULL);
 246 }
 247
 248 EXPORT_SYMBOL_GPL(kobject_uevent);
 249
 250 /**
 251  * add_uevent_var - helper for creating event variables
 252  * @envp: Pointer to table of environment variables, as passed into
 253  * uevent() method.
 254  * @num_envp: Number of environment variable slots available, as
 255  * passed into uevent() method.
 256  * @cur_index: Pointer to current index into @envp.  It should be
 257  * initialized to 0 before the first call to add_uevent_var(),
 258  * and will be incremented on success.
 259  * @buffer: Pointer to buffer for environment variables, as passed
 260  * into uevent() method.
 261  * @buffer_size: Length of @buffer, as passed into uevent() method.
 262  * @cur_len: Pointer to current length of space used in @buffer.
 263  * Should be initialized to 0 before the first call to
 264  * add_uevent_var(), and will be incremented on success.
 265  * @format: Format for creating environment variable (of the form
 266  * "XXX=%x") for snprintf().
 267  *
 268  * Returns 0 if environment variable was added successfully or -ENOMEM
 269  * if no space was available.
 270  */
 271 int add_uevent_var(char **envp, int num_envp, int *cur_index,
 272                    char *buffer, int buffer_size, int *cur_len,
 273                    const char *format, ...)
 274 {
 275         va_list args;
 276
 277         /*
 278          * We check against num_envp - 1 to make sure there is at
 279          * least one slot left after we return, since kobject_uevent()
 280          * needs to set the last slot to NULL.
 281          */
 282         if (*cur_index >= num_envp - 1)
 283                 return -ENOMEM;
 284
 285         envp[*cur_index] = buffer + *cur_len;
 286
 287         va_start(args, format);
 288         *cur_len += vsnprintf(envp[*cur_index],
 289                               max(buffer_size - *cur_len, 0),
 290                               format, args) + 1;
 291         va_end(args);
 292
 293         if (*cur_len > buffer_size)
 294                 return -ENOMEM;
 295
 296         (*cur_index)++;
 297         return 0;
 298 }
 299 EXPORT_SYMBOL_GPL(add_uevent_var);
 300
 301 #if defined(CONFIG_NET)
 302 static int __init kobject_uevent_init(void)
 303 {
 304         uevent_sock = netlink_kernel_create(NETLINK_KOBJECT_UEVENT, 1, NULL,
 305                                             NULL, THIS_MODULE);
 306
 307         if (!uevent_sock) {
 308                 printk(KERN_ERR
 309                        "kobject_uevent: unable to create netlink socket!\n");
 310                 return -ENODEV;
 311         }
 312
 313         return 0;
 314 }
 315
 316 postcore_initcall(kobject_uevent_init);
 317 #endif
 318
 319 #endif /* CONFIG_HOTPLUG */