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