lib/kobject.c

   1 /*
   2  * kobject.c - library routines for handling generic kernel objects
   3  *
   4  * Copyright (c) 2002-2003 Patrick Mochel <mochel@osdl.org>
   5  * Copyright (c) 2006-2007 Greg Kroah-Hartman <greg@kroah.com>
   6  * Copyright (c) 2006-2007 Novell Inc.
   7  *
   8  * This file is released under the GPLv2.
   9  *
  10  *
  11  * Please see the file Documentation/kobject.txt for critical information
  12  * about using the kobject interface.
  13  */
  14
  15 #include <linux/kobject.h>
  16 #include <linux/string.h>
  17 #include <linux/export.h>
  18 #include <linux/stat.h>
  19 #include <linux/slab.h>
  20 #include <linux/random.h>
  21
  22 /**
  23  * kobject_namespace - return @kobj's namespace tag
  24  * @kobj: kobject in question
  25  *
  26  * Returns namespace tag of @kobj if its parent has namespace ops enabled
  27  * and thus @kobj should have a namespace tag associated with it.  Returns
  28  * %NULL otherwise.
  29  */
  30 const void *kobject_namespace(struct kobject *kobj)
  31 {
  32         const struct kobj_ns_type_operations *ns_ops = kobj_ns_ops(kobj);
  33
  34         if (!ns_ops || ns_ops->type == KOBJ_NS_TYPE_NONE)
  35                 return NULL;
  36
  37         return kobj->ktype->namespace(kobj);
  38 }
  39
  40 /*
  41  * populate_dir - populate directory with attributes.
  42  * @kobj: object we're working on.
  43  *
  44  * Most subsystems have a set of default attributes that are associated
  45  * with an object that registers with them.  This is a helper called during
  46  * object registration that loops through the default attributes of the
  47  * subsystem and creates attributes files for them in sysfs.
  48  */
  49 static int populate_dir(struct kobject *kobj)
  50 {
  51         struct kobj_type *t = get_ktype(kobj);
  52         struct attribute *attr;
  53         int error = 0;
  54         int i;
  55
  56         if (t && t->default_attrs) {
  57                 for (i = 0; (attr = t->default_attrs[i]) != NULL; i++) {
  58                         error = sysfs_create_file(kobj, attr);
  59                         if (error)
  60                                 break;
  61                 }
  62         }
  63         return error;
  64 }
  65
  66 static int create_dir(struct kobject *kobj)
  67 {
  68         const struct kobj_ns_type_operations *ops;
  69         int error;
  70
  71         error = sysfs_create_dir_ns(kobj, kobject_namespace(kobj));
  72         if (error)
  73                 return error;
  74
  75         error = populate_dir(kobj);
  76         if (error) {
  77                 sysfs_remove_dir(kobj);
  78                 return error;
  79         }
  80
  81         /*
  82          * @kobj->sd may be deleted by an ancestor going away.  Hold an
  83          * extra reference so that it stays until @kobj is gone.
  84          */
  85         sysfs_get(kobj->sd);
  86
  87         /*
  88          * If @kobj has ns_ops, its children need to be filtered based on
  89          * their namespace tags.  Enable namespace support on @kobj->sd.
  90          */
  91         ops = kobj_child_ns_ops(kobj);
  92         if (ops) {
  93                 BUG_ON(ops->type <= KOBJ_NS_TYPE_NONE);
  94                 BUG_ON(ops->type >= KOBJ_NS_TYPES);
  95                 BUG_ON(!kobj_ns_type_registered(ops->type));
  96
  97                 sysfs_enable_ns(kobj->sd);
  98         }
  99
 100         return 0;
 101 }
 102
 103 static int get_kobj_path_length(struct kobject *kobj)
 104 {
 105         int length = 1;
 106         struct kobject *parent = kobj;
 107
 108         /* walk up the ancestors until we hit the one pointing to the
 109          * root.
 110          * Add 1 to strlen for leading '/' of each level.
 111          */
 112         do {
 113                 if (kobject_name(parent) == NULL)
 114                         return 0;
 115                 length += strlen(kobject_name(parent)) + 1;
 116                 parent = parent->parent;
 117         } while (parent);
 118         return length;
 119 }
 120
 121 static void fill_kobj_path(struct kobject *kobj, char *path, int length)
 122 {
 123         struct kobject *parent;
 124
 125         --length;
 126         for (parent = kobj; parent; parent = parent->parent) {
 127                 int cur = strlen(kobject_name(parent));
 128                 /* back up enough to print this name with '/' */
 129                 length -= cur;
 130                 memcpy(path + length, kobject_name(parent), cur);
 131                 *(path + --length) = '/';
 132         }
 133
 134         pr_debug("kobject: '%s' (%p): %s: path = '%s'\n", kobject_name(kobj),
 135                  kobj, __func__, path);
 136 }
 137
 138 /**
 139  * kobject_get_path - generate and return the path associated with a given kobj and kset pair.
 140  *
 141  * @kobj:       kobject in question, with which to build the path
 142  * @gfp_mask:   the allocation type used to allocate the path
 143  *
 144  * The result must be freed by the caller with kfree().
 145  */
 146 char *kobject_get_path(struct kobject *kobj, gfp_t gfp_mask)
 147 {
 148         char *path;
 149         int len;
 150
 151         len = get_kobj_path_length(kobj);
 152         if (len == 0)
 153                 return NULL;
 154         path = kzalloc(len, gfp_mask);
 155         if (!path)
 156                 return NULL;
 157         fill_kobj_path(kobj, path, len);
 158
 159         return path;
 160 }
 161 EXPORT_SYMBOL_GPL(kobject_get_path);
 162
 163 /* add the kobject to its kset's list */
 164 static void kobj_kset_join(struct kobject *kobj)
 165 {
 166         if (!kobj->kset)
 167                 return;
 168
 169         kset_get(kobj->kset);
 170         spin_lock(&kobj->kset->list_lock);
 171         list_add_tail(&kobj->entry, &kobj->kset->list);
 172         spin_unlock(&kobj->kset->list_lock);
 173 }
 174
 175 /* remove the kobject from its kset's list */
 176 static void kobj_kset_leave(struct kobject *kobj)
 177 {
 178         if (!kobj->kset)
 179                 return;
 180
 181         spin_lock(&kobj->kset->list_lock);
 182         list_del_init(&kobj->entry);
 183         spin_unlock(&kobj->kset->list_lock);
 184         kset_put(kobj->kset);
 185 }
 186
 187 static void kobject_init_internal(struct kobject *kobj)
 188 {
 189         if (!kobj)
 190                 return;
 191         kref_init(&kobj->kref);
 192         INIT_LIST_HEAD(&kobj->entry);
 193         kobj->state_in_sysfs = 0;
 194         kobj->state_add_uevent_sent = 0;
 195         kobj->state_remove_uevent_sent = 0;
 196         kobj->state_initialized = 1;
 197 }
 198
 199
 200 static int kobject_add_internal(struct kobject *kobj)
 201 {
 202         int error = 0;
 203         struct kobject *parent;
 204
 205         if (!kobj)
 206                 return -ENOENT;
 207
 208         if (!kobj->name || !kobj->name[0]) {
 209                 WARN(1, "kobject: (%p): attempted to be registered with empty "
 210                          "name!\n", kobj);
 211                 return -EINVAL;
 212         }
 213
 214         parent = kobject_get(kobj->parent);
 215
 216         /* join kset if set, use it as parent if we do not already have one */
 217         if (kobj->kset) {
 218                 if (!parent)
 219                         parent = kobject_get(&kobj->kset->kobj);
 220                 kobj_kset_join(kobj);
 221                 kobj->parent = parent;
 222         }
 223
 224         pr_debug("kobject: '%s' (%p): %s: parent: '%s', set: '%s'\n",
 225                  kobject_name(kobj), kobj, __func__,
 226                  parent ? kobject_name(parent) : "<NULL>",
 227                  kobj->kset ? kobject_name(&kobj->kset->kobj) : "<NULL>");
 228
 229         error = create_dir(kobj);
 230         if (error) {
 231                 kobj_kset_leave(kobj);
 232                 kobject_put(parent);
 233                 kobj->parent = NULL;
 234
 235                 /* be noisy on error issues */
 236                 if (error == -EEXIST)
 237                         pr_err("%s failed for %s with -EEXIST, don't try to register things with the same name in the same directory.\n",
 238                                __func__, kobject_name(kobj));
 239                 else
 240                         pr_err("%s failed for %s (error: %d parent: %s)\n",
 241                                __func__, kobject_name(kobj), error,
 242                                parent ? kobject_name(parent) : "'none'");
 243         } else
 244                 kobj->state_in_sysfs = 1;
 245
 246         return error;
 247 }
 248
 249 /**
 250  * kobject_set_name_vargs - Set the name of an kobject
 251  * @kobj: struct kobject to set the name of
 252  * @fmt: format string used to build the name
 253  * @vargs: vargs to format the string.
 254  */
 255 int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
 256                                   va_list vargs)
 257 {
 258         const char *s;
 259
 260         if (kobj->name && !fmt)
 261                 return 0;
 262
 263         s = kvasprintf_const(GFP_KERNEL, fmt, vargs);
 264         if (!s)
 265                 return -ENOMEM;
 266
 267         /*
 268          * ewww... some of these buggers have '/' in the name ... If
 269          * that's the case, we need to make sure we have an actual
 270          * allocated copy to modify, since kvasprintf_const may have
 271          * returned something from .rodata.
 272          */
 273         if (strchr(s, '/')) {
 274                 char *t;
 275
 276                 t = kstrdup(s, GFP_KERNEL);
 277                 kfree_const(s);
 278                 if (!t)
 279                         return -ENOMEM;
 280                 strreplace(t, '/', '!');
 281                 s = t;
 282         }
 283         kfree_const(kobj->name);
 284         kobj->name = s;
 285
 286         return 0;
 287 }
 288
 289 /**
 290  * kobject_set_name - Set the name of a kobject
 291  * @kobj: struct kobject to set the name of
 292  * @fmt: format string used to build the name
 293  *
 294  * This sets the name of the kobject.  If you have already added the
 295  * kobject to the system, you must call kobject_rename() in order to
 296  * change the name of the kobject.
 297  */
 298 int kobject_set_name(struct kobject *kobj, const char *fmt, ...)
 299 {
 300         va_list vargs;
 301         int retval;
 302
 303         va_start(vargs, fmt);
 304         retval = kobject_set_name_vargs(kobj, fmt, vargs);
 305         va_end(vargs);
 306
 307         return retval;
 308 }
 309 EXPORT_SYMBOL(kobject_set_name);
 310
 311 /**
 312  * kobject_init - initialize a kobject structure
 313  * @kobj: pointer to the kobject to initialize
 314  * @ktype: pointer to the ktype for this kobject.
 315  *
 316  * This function will properly initialize a kobject such that it can then
 317  * be passed to the kobject_add() call.
 318  *
 319  * After this function is called, the kobject MUST be cleaned up by a call
 320  * to kobject_put(), not by a call to kfree directly to ensure that all of
 321  * the memory is cleaned up properly.
 322  */
 323 void kobject_init(struct kobject *kobj, struct kobj_type *ktype)
 324 {
 325         char *err_str;
 326
 327         if (!kobj) {
 328                 err_str = "invalid kobject pointer!";
 329                 goto error;
 330         }
 331         if (!ktype) {
 332                 err_str = "must have a ktype to be initialized properly!\n";
 333                 goto error;
 334         }
 335         if (kobj->state_initialized) {
 336                 /* do not error out as sometimes we can recover */
 337                 printk(KERN_ERR "kobject (%p): tried to init an initialized "
 338                        "object, something is seriously wrong.\n", kobj);
 339                 dump_stack();
 340         }
 341
 342         kobject_init_internal(kobj);
 343         kobj->ktype = ktype;
 344         return;
 345
 346 error:
 347         printk(KERN_ERR "kobject (%p): %s\n", kobj, err_str);
 348         dump_stack();
 349 }
 350 EXPORT_SYMBOL(kobject_init);
 351
 352 static __printf(3, 0) int kobject_add_varg(struct kobject *kobj,
 353                                            struct kobject *parent,
 354                                            const char *fmt, va_list vargs)
 355 {
 356         int retval;
 357
 358         retval = kobject_set_name_vargs(kobj, fmt, vargs);
 359         if (retval) {
 360                 printk(KERN_ERR "kobject: can not set name properly!\n");
 361                 return retval;
 362         }
 363         kobj->parent = parent;
 364         return kobject_add_internal(kobj);
 365 }
 366
 367 /**
 368  * kobject_add - the main kobject add function
 369  * @kobj: the kobject to add
 370  * @parent: pointer to the parent of the kobject.
 371  * @fmt: format to name the kobject with.
 372  *
 373  * The kobject name is set and added to the kobject hierarchy in this
 374  * function.
 375  *
 376  * If @parent is set, then the parent of the @kobj will be set to it.
 377  * If @parent is NULL, then the parent of the @kobj will be set to the
 378  * kobject associated with the kset assigned to this kobject.  If no kset
 379  * is assigned to the kobject, then the kobject will be located in the
 380  * root of the sysfs tree.
 381  *
 382  * If this function returns an error, kobject_put() must be called to
 383  * properly clean up the memory associated with the object.
 384  * Under no instance should the kobject that is passed to this function
 385  * be directly freed with a call to kfree(), that can leak memory.
 386  *
 387  * Note, no "add" uevent will be created with this call, the caller should set
 388  * up all of the necessary sysfs files for the object and then call
 389  * kobject_uevent() with the UEVENT_ADD parameter to ensure that
 390  * userspace is properly notified of this kobject's creation.
 391  */
 392 int kobject_add(struct kobject *kobj, struct kobject *parent,
 393                 const char *fmt, ...)
 394 {
 395         va_list args;
 396         int retval;
 397
 398         if (!kobj)
 399                 return -EINVAL;
 400
 401         if (!kobj->state_initialized) {
 402                 printk(KERN_ERR "kobject '%s' (%p): tried to add an "
 403                        "uninitialized object, something is seriously wrong.\n",
 404                        kobject_name(kobj), kobj);
 405                 dump_stack();
 406                 return -EINVAL;
 407         }
 408         va_start(args, fmt);
 409         retval = kobject_add_varg(kobj, parent, fmt, args);
 410         va_end(args);
 411
 412         return retval;
 413 }
 414 EXPORT_SYMBOL(kobject_add);
 415
 416 /**
 417  * kobject_init_and_add - initialize a kobject structure and add it to the kobject hierarchy
 418  * @kobj: pointer to the kobject to initialize
 419  * @ktype: pointer to the ktype for this kobject.
 420  * @parent: pointer to the parent of this kobject.
 421  * @fmt: the name of the kobject.
 422  *
 423  * This function combines the call to kobject_init() and
 424  * kobject_add().  The same type of error handling after a call to
 425  * kobject_add() and kobject lifetime rules are the same here.
 426  */
 427 int kobject_init_and_add(struct kobject *kobj, struct kobj_type *ktype,
 428                          struct kobject *parent, const char *fmt, ...)
 429 {
 430         va_list args;
 431         int retval;
 432
 433         kobject_init(kobj, ktype);
 434
 435         va_start(args, fmt);
 436         retval = kobject_add_varg(kobj, parent, fmt, args);
 437         va_end(args);
 438
 439         return retval;
 440 }
 441 EXPORT_SYMBOL_GPL(kobject_init_and_add);
 442
 443 /**
 444  * kobject_rename - change the name of an object
 445  * @kobj: object in question.
 446  * @new_name: object's new name
 447  *
 448  * It is the responsibility of the caller to provide mutual
 449  * exclusion between two different calls of kobject_rename
 450  * on the same kobject and to ensure that new_name is valid and
 451  * won't conflict with other kobjects.
 452  */
 453 int kobject_rename(struct kobject *kobj, const char *new_name)
 454 {
 455         int error = 0;
 456         const char *devpath = NULL;
 457         const char *dup_name = NULL, *name;
 458         char *devpath_string = NULL;
 459         char *envp[2];
 460
 461         kobj = kobject_get(kobj);
 462         if (!kobj)
 463                 return -EINVAL;
 464         if (!kobj->parent)
 465                 return -EINVAL;
 466
 467         devpath = kobject_get_path(kobj, GFP_KERNEL);
 468         if (!devpath) {
 469                 error = -ENOMEM;
 470                 goto out;
 471         }
 472         devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
 473         if (!devpath_string) {
 474                 error = -ENOMEM;
 475                 goto out;
 476         }
 477         sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
 478         envp[0] = devpath_string;
 479         envp[1] = NULL;
 480
 481         name = dup_name = kstrdup_const(new_name, GFP_KERNEL);
 482         if (!name) {
 483                 error = -ENOMEM;
 484                 goto out;
 485         }
 486
 487         error = sysfs_rename_dir_ns(kobj, new_name, kobject_namespace(kobj));
 488         if (error)
 489                 goto out;
 490
 491         /* Install the new kobject name */
 492         dup_name = kobj->name;
 493         kobj->name = name;
 494
 495         /* This function is mostly/only used for network interface.
 496          * Some hotplug package track interfaces by their name and
 497          * therefore want to know when the name is changed by the user. */
 498         kobject_uevent_env(kobj, KOBJ_MOVE, envp);
 499
 500 out:
 501         kfree_const(dup_name);
 502         kfree(devpath_string);
 503         kfree(devpath);
 504         kobject_put(kobj);
 505
 506         return error;
 507 }
 508 EXPORT_SYMBOL_GPL(kobject_rename);
 509
 510 /**
 511  * kobject_move - move object to another parent
 512  * @kobj: object in question.
 513  * @new_parent: object's new parent (can be NULL)
 514  */
 515 int kobject_move(struct kobject *kobj, struct kobject *new_parent)
 516 {
 517         int error;
 518         struct kobject *old_parent;
 519         const char *devpath = NULL;
 520         char *devpath_string = NULL;
 521         char *envp[2];
 522
 523         kobj = kobject_get(kobj);
 524         if (!kobj)
 525                 return -EINVAL;
 526         new_parent = kobject_get(new_parent);
 527         if (!new_parent) {
 528                 if (kobj->kset)
 529                         new_parent = kobject_get(&kobj->kset->kobj);
 530         }
 531
 532         /* old object path */
 533         devpath = kobject_get_path(kobj, GFP_KERNEL);
 534         if (!devpath) {
 535                 error = -ENOMEM;
 536                 goto out;
 537         }
 538         devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
 539         if (!devpath_string) {
 540                 error = -ENOMEM;
 541                 goto out;
 542         }
 543         sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
 544         envp[0] = devpath_string;
 545         envp[1] = NULL;
 546         error = sysfs_move_dir_ns(kobj, new_parent, kobject_namespace(kobj));
 547         if (error)
 548                 goto out;
 549         old_parent = kobj->parent;
 550         kobj->parent = new_parent;
 551         new_parent = NULL;
 552         kobject_put(old_parent);
 553         kobject_uevent_env(kobj, KOBJ_MOVE, envp);
 554 out:
 555         kobject_put(new_parent);
 556         kobject_put(kobj);
 557         kfree(devpath_string);
 558         kfree(devpath);
 559         return error;
 560 }
 561 EXPORT_SYMBOL_GPL(kobject_move);
 562
 563 /**
 564  * kobject_del - unlink kobject from hierarchy.
 565  * @kobj: object.
 566  */
 567 void kobject_del(struct kobject *kobj)
 568 {
 569         struct kernfs_node *sd;
 570
 571         if (!kobj)
 572                 return;
 573
 574         sd = kobj->sd;
 575         sysfs_remove_dir(kobj);
 576         sysfs_put(sd);
 577
 578         kobj->state_in_sysfs = 0;
 579         kobj_kset_leave(kobj);
 580         kobject_put(kobj->parent);
 581         kobj->parent = NULL;
 582 }
 583 EXPORT_SYMBOL(kobject_del);
 584
 585 /**
 586  * kobject_get - increment refcount for object.
 587  * @kobj: object.
 588  */
 589 struct kobject *kobject_get(struct kobject *kobj)
 590 {
 591         if (kobj) {
 592                 if (!kobj->state_initialized)
 593                         WARN(1, KERN_WARNING "kobject: '%s' (%p): is not "
 594                                "initialized, yet kobject_get() is being "
 595                                "called.\n", kobject_name(kobj), kobj);
 596                 kref_get(&kobj->kref);
 597         }
 598         return kobj;
 599 }
 600 EXPORT_SYMBOL(kobject_get);
 601
 602 struct kobject * __must_check kobject_get_unless_zero(struct kobject *kobj)
 603 {
 604         if (!kobj)
 605                 return NULL;
 606         if (!kref_get_unless_zero(&kobj->kref))
 607                 kobj = NULL;
 608         return kobj;
 609 }
 610 EXPORT_SYMBOL(kobject_get_unless_zero);
 611
 612 /*
 613  * kobject_cleanup - free kobject resources.
 614  * @kobj: object to cleanup
 615  */
 616 static void kobject_cleanup(struct kobject *kobj)
 617 {
 618         struct kobj_type *t = get_ktype(kobj);
 619         const char *name = kobj->name;
 620
 621         pr_debug("kobject: '%s' (%p): %s, parent %p\n",
 622                  kobject_name(kobj), kobj, __func__, kobj->parent);
 623
 624         if (t && !t->release)
 625                 pr_debug("kobject: '%s' (%p): does not have a release() "
 626                          "function, it is broken and must be fixed.\n",
 627                          kobject_name(kobj), kobj);
 628
 629         /* send "remove" if the caller did not do it but sent "add" */
 630         if (kobj->state_add_uevent_sent && !kobj->state_remove_uevent_sent) {
 631                 pr_debug("kobject: '%s' (%p): auto cleanup 'remove' event\n",
 632                          kobject_name(kobj), kobj);
 633                 kobject_uevent(kobj, KOBJ_REMOVE);
 634         }
 635
 636         /* remove from sysfs if the caller did not do it */
 637         if (kobj->state_in_sysfs) {
 638                 pr_debug("kobject: '%s' (%p): auto cleanup kobject_del\n",
 639                          kobject_name(kobj), kobj);
 640                 kobject_del(kobj);
 641         }
 642
 643         if (t && t->release) {
 644                 pr_debug("kobject: '%s' (%p): calling ktype release\n",
 645                          kobject_name(kobj), kobj);
 646                 t->release(kobj);
 647         }
 648
 649         /* free name if we allocated it */
 650         if (name) {
 651                 pr_debug("kobject: '%s': free name\n", name);
 652                 kfree_const(name);
 653         }
 654 }
 655
 656 #ifdef CONFIG_DEBUG_KOBJECT_RELEASE
 657 static void kobject_delayed_cleanup(struct work_struct *work)
 658 {
 659         kobject_cleanup(container_of(to_delayed_work(work),
 660                                      struct kobject, release));
 661 }
 662 #endif
 663
 664 static void kobject_release(struct kref *kref)
 665 {
 666         struct kobject *kobj = container_of(kref, struct kobject, kref);
 667 #ifdef CONFIG_DEBUG_KOBJECT_RELEASE
 668         unsigned long delay = HZ + HZ * (get_random_int() & 0x3);
 669         pr_info("kobject: '%s' (%p): %s, parent %p (delayed %ld)\n",
 670                  kobject_name(kobj), kobj, __func__, kobj->parent, delay);
 671         INIT_DELAYED_WORK(&kobj->release, kobject_delayed_cleanup);
 672
 673         schedule_delayed_work(&kobj->release, delay);
 674 #else
 675         kobject_cleanup(kobj);
 676 #endif
 677 }
 678
 679 /**
 680  * kobject_put - decrement refcount for object.
 681  * @kobj: object.
 682  *
 683  * Decrement the refcount, and if 0, call kobject_cleanup().
 684  */
 685 void kobject_put(struct kobject *kobj)
 686 {
 687         if (kobj) {
 688                 if (!kobj->state_initialized)
 689                         WARN(1, KERN_WARNING "kobject: '%s' (%p): is not "
 690                                "initialized, yet kobject_put() is being "
 691                                "called.\n", kobject_name(kobj), kobj);
 692                 kref_put(&kobj->kref, kobject_release);
 693         }
 694 }
 695 EXPORT_SYMBOL(kobject_put);
 696
 697 static void dynamic_kobj_release(struct kobject *kobj)
 698 {
 699         pr_debug("kobject: (%p): %s\n", kobj, __func__);
 700         kfree(kobj);
 701 }
 702
 703 static struct kobj_type dynamic_kobj_ktype = {
 704         .release        = dynamic_kobj_release,
 705         .sysfs_ops      = &kobj_sysfs_ops,
 706 };
 707
 708 /**
 709  * kobject_create - create a struct kobject dynamically
 710  *
 711  * This function creates a kobject structure dynamically and sets it up
 712  * to be a "dynamic" kobject with a default release function set up.
 713  *
 714  * If the kobject was not able to be created, NULL will be returned.
 715  * The kobject structure returned from here must be cleaned up with a
 716  * call to kobject_put() and not kfree(), as kobject_init() has
 717  * already been called on this structure.
 718  */
 719 struct kobject *kobject_create(void)
 720 {
 721         struct kobject *kobj;
 722
 723         kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
 724         if (!kobj)
 725                 return NULL;
 726
 727         kobject_init(kobj, &dynamic_kobj_ktype);
 728         return kobj;
 729 }
 730
 731 /**
 732  * kobject_create_and_add - create a struct kobject dynamically and register it with sysfs
 733  *
 734  * @name: the name for the kobject
 735  * @parent: the parent kobject of this kobject, if any.
 736  *
 737  * This function creates a kobject structure dynamically and registers it
 738  * with sysfs.  When you are finished with this structure, call
 739  * kobject_put() and the structure will be dynamically freed when
 740  * it is no longer being used.
 741  *
 742  * If the kobject was not able to be created, NULL will be returned.
 743  */
 744 struct kobject *kobject_create_and_add(const char *name, struct kobject *parent)
 745 {
 746         struct kobject *kobj;
 747         int retval;
 748
 749         kobj = kobject_create();
 750         if (!kobj)
 751                 return NULL;
 752
 753         retval = kobject_add(kobj, parent, "%s", name);
 754         if (retval) {
 755                 printk(KERN_WARNING "%s: kobject_add error: %d\n",
 756                        __func__, retval);
 757                 kobject_put(kobj);
 758                 kobj = NULL;
 759         }
 760         return kobj;
 761 }
 762 EXPORT_SYMBOL_GPL(kobject_create_and_add);
 763
 764 /**
 765  * kset_init - initialize a kset for use
 766  * @k: kset
 767  */
 768 void kset_init(struct kset *k)
 769 {
 770         kobject_init_internal(&k->kobj);
 771         INIT_LIST_HEAD(&k->list);
 772         spin_lock_init(&k->list_lock);
 773 }
 774
 775 /* default kobject attribute operations */
 776 static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr,
 777                               char *buf)
 778 {
 779         struct kobj_attribute *kattr;
 780         ssize_t ret = -EIO;
 781
 782         kattr = container_of(attr, struct kobj_attribute, attr);
 783         if (kattr->show)
 784                 ret = kattr->show(kobj, kattr, buf);
 785         return ret;
 786 }
 787
 788 static ssize_t kobj_attr_store(struct kobject *kobj, struct attribute *attr,
 789                                const char *buf, size_t count)
 790 {
 791         struct kobj_attribute *kattr;
 792         ssize_t ret = -EIO;
 793
 794         kattr = container_of(attr, struct kobj_attribute, attr);
 795         if (kattr->store)
 796                 ret = kattr->store(kobj, kattr, buf, count);
 797         return ret;
 798 }
 799
 800 const struct sysfs_ops kobj_sysfs_ops = {
 801         .show   = kobj_attr_show,
 802         .store  = kobj_attr_store,
 803 };
 804 EXPORT_SYMBOL_GPL(kobj_sysfs_ops);
 805
 806 /**
 807  * kset_register - initialize and add a kset.
 808  * @k: kset.
 809  */
 810 int kset_register(struct kset *k)
 811 {
 812         int err;
 813
 814         if (!k)
 815                 return -EINVAL;
 816
 817         kset_init(k);
 818         err = kobject_add_internal(&k->kobj);
 819         if (err)
 820                 return err;
 821         kobject_uevent(&k->kobj, KOBJ_ADD);
 822         return 0;
 823 }
 824 EXPORT_SYMBOL(kset_register);
 825
 826 /**
 827  * kset_unregister - remove a kset.
 828  * @k: kset.
 829  */
 830 void kset_unregister(struct kset *k)
 831 {
 832         if (!k)
 833                 return;
 834         kobject_del(&k->kobj);
 835         kobject_put(&k->kobj);
 836 }
 837 EXPORT_SYMBOL(kset_unregister);
 838
 839 /**
 840  * kset_find_obj - search for object in kset.
 841  * @kset: kset we're looking in.
 842  * @name: object's name.
 843  *
 844  * Lock kset via @kset->subsys, and iterate over @kset->list,
 845  * looking for a matching kobject. If matching object is found
 846  * take a reference and return the object.
 847  */
 848 struct kobject *kset_find_obj(struct kset *kset, const char *name)
 849 {
 850         struct kobject *k;
 851         struct kobject *ret = NULL;
 852
 853         spin_lock(&kset->list_lock);
 854
 855         list_for_each_entry(k, &kset->list, entry) {
 856                 if (kobject_name(k) && !strcmp(kobject_name(k), name)) {
 857                         ret = kobject_get_unless_zero(k);
 858                         break;
 859                 }
 860         }
 861
 862         spin_unlock(&kset->list_lock);
 863         return ret;
 864 }
 865 EXPORT_SYMBOL_GPL(kset_find_obj);
 866
 867 static void kset_release(struct kobject *kobj)
 868 {
 869         struct kset *kset = container_of(kobj, struct kset, kobj);
 870         pr_debug("kobject: '%s' (%p): %s\n",
 871                  kobject_name(kobj), kobj, __func__);
 872         kfree(kset);
 873 }
 874
 875 static struct kobj_type kset_ktype = {
 876         .sysfs_ops      = &kobj_sysfs_ops,
 877         .release = kset_release,
 878 };
 879
 880 /**
 881  * kset_create - create a struct kset dynamically
 882  *
 883  * @name: the name for the kset
 884  * @uevent_ops: a struct kset_uevent_ops for the kset
 885  * @parent_kobj: the parent kobject of this kset, if any.
 886  *
 887  * This function creates a kset structure dynamically.  This structure can
 888  * then be registered with the system and show up in sysfs with a call to
 889  * kset_register().  When you are finished with this structure, if
 890  * kset_register() has been called, call kset_unregister() and the
 891  * structure will be dynamically freed when it is no longer being used.
 892  *
 893  * If the kset was not able to be created, NULL will be returned.
 894  */
 895 static struct kset *kset_create(const char *name,
 896                                 const struct kset_uevent_ops *uevent_ops,
 897                                 struct kobject *parent_kobj)
 898 {
 899         struct kset *kset;
 900         int retval;
 901
 902         kset = kzalloc(sizeof(*kset), GFP_KERNEL);
 903         if (!kset)
 904                 return NULL;
 905         retval = kobject_set_name(&kset->kobj, "%s", name);
 906         if (retval) {
 907                 kfree(kset);
 908                 return NULL;
 909         }
 910         kset->uevent_ops = uevent_ops;
 911         kset->kobj.parent = parent_kobj;
 912
 913         /*
 914          * The kobject of this kset will have a type of kset_ktype and belong to
 915          * no kset itself.  That way we can properly free it when it is
 916          * finished being used.
 917          */
 918         kset->kobj.ktype = &kset_ktype;
 919         kset->kobj.kset = NULL;
 920
 921         return kset;
 922 }
 923
 924 /**
 925  * kset_create_and_add - create a struct kset dynamically and add it to sysfs
 926  *
 927  * @name: the name for the kset
 928  * @uevent_ops: a struct kset_uevent_ops for the kset
 929  * @parent_kobj: the parent kobject of this kset, if any.
 930  *
 931  * This function creates a kset structure dynamically and registers it
 932  * with sysfs.  When you are finished with this structure, call
 933  * kset_unregister() and the structure will be dynamically freed when it
 934  * is no longer being used.
 935  *
 936  * If the kset was not able to be created, NULL will be returned.
 937  */
 938 struct kset *kset_create_and_add(const char *name,
 939                                  const struct kset_uevent_ops *uevent_ops,
 940                                  struct kobject *parent_kobj)
 941 {
 942         struct kset *kset;
 943         int error;
 944
 945         kset = kset_create(name, uevent_ops, parent_kobj);
 946         if (!kset)
 947                 return NULL;
 948         error = kset_register(kset);
 949         if (error) {
 950                 kfree(kset);
 951                 return NULL;
 952         }
 953         return kset;
 954 }
 955 EXPORT_SYMBOL_GPL(kset_create_and_add);
 956
 957
 958 static DEFINE_SPINLOCK(kobj_ns_type_lock);
 959 static const struct kobj_ns_type_operations *kobj_ns_ops_tbl[KOBJ_NS_TYPES];
 960
 961 int kobj_ns_type_register(const struct kobj_ns_type_operations *ops)
 962 {
 963         enum kobj_ns_type type = ops->type;
 964         int error;
 965
 966         spin_lock(&kobj_ns_type_lock);
 967
 968         error = -EINVAL;
 969         if (type >= KOBJ_NS_TYPES)
 970                 goto out;
 971
 972         error = -EINVAL;
 973         if (type <= KOBJ_NS_TYPE_NONE)
 974                 goto out;
 975
 976         error = -EBUSY;
 977         if (kobj_ns_ops_tbl[type])
 978                 goto out;
 979
 980         error = 0;
 981         kobj_ns_ops_tbl[type] = ops;
 982
 983 out:
 984         spin_unlock(&kobj_ns_type_lock);
 985         return error;
 986 }
 987
 988 int kobj_ns_type_registered(enum kobj_ns_type type)
 989 {
 990         int registered = 0;
 991
 992         spin_lock(&kobj_ns_type_lock);
 993         if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES))
 994                 registered = kobj_ns_ops_tbl[type] != NULL;
 995         spin_unlock(&kobj_ns_type_lock);
 996
 997         return registered;
 998 }
 999
1000 const struct kobj_ns_type_operations *kobj_child_ns_ops(struct kobject *parent)
1001 {
1002         const struct kobj_ns_type_operations *ops = NULL;
1003
1004         if (parent && parent->ktype && parent->ktype->child_ns_type)
1005                 ops = parent->ktype->child_ns_type(parent);
1006
1007         return ops;
1008 }
1009
1010 const struct kobj_ns_type_operations *kobj_ns_ops(struct kobject *kobj)
1011 {
1012         return kobj_child_ns_ops(kobj->parent);
1013 }
1014
1015 bool kobj_ns_current_may_mount(enum kobj_ns_type type)
1016 {
1017         bool may_mount = true;
1018
1019         spin_lock(&kobj_ns_type_lock);
1020         if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1021             kobj_ns_ops_tbl[type])
1022                 may_mount = kobj_ns_ops_tbl[type]->current_may_mount();
1023         spin_unlock(&kobj_ns_type_lock);
1024
1025         return may_mount;
1026 }
1027
1028 void *kobj_ns_grab_current(enum kobj_ns_type type)
1029 {
1030         void *ns = NULL;
1031
1032         spin_lock(&kobj_ns_type_lock);
1033         if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1034             kobj_ns_ops_tbl[type])
1035                 ns = kobj_ns_ops_tbl[type]->grab_current_ns();
1036         spin_unlock(&kobj_ns_type_lock);
1037
1038         return ns;
1039 }
1040
1041 const void *kobj_ns_netlink(enum kobj_ns_type type, struct sock *sk)
1042 {
1043         const void *ns = NULL;
1044
1045         spin_lock(&kobj_ns_type_lock);
1046         if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1047             kobj_ns_ops_tbl[type])
1048                 ns = kobj_ns_ops_tbl[type]->netlink_ns(sk);
1049         spin_unlock(&kobj_ns_type_lock);
1050
1051         return ns;
1052 }
1053
1054 const void *kobj_ns_initial(enum kobj_ns_type type)
1055 {
1056         const void *ns = NULL;
1057
1058         spin_lock(&kobj_ns_type_lock);
1059         if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1060             kobj_ns_ops_tbl[type])
1061                 ns = kobj_ns_ops_tbl[type]->initial_ns();
1062         spin_unlock(&kobj_ns_type_lock);
1063
1064         return ns;
1065 }
1066
1067 void kobj_ns_drop(enum kobj_ns_type type, void *ns)
1068 {
1069         spin_lock(&kobj_ns_type_lock);
1070         if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1071             kobj_ns_ops_tbl[type] && kobj_ns_ops_tbl[type]->drop_ns)
1072                 kobj_ns_ops_tbl[type]->drop_ns(ns);
1073         spin_unlock(&kobj_ns_type_lock);
1074 }