linux/lib/kobject.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * kobject.c - library routines for handling generic kernel objects
   4 *
   5 * Copyright (c) 2002-2003 Patrick Mochel <mochel@osdl.org>
   6 * Copyright (c) 2006-2007 Greg Kroah-Hartman <greg@kroah.com>
   7 * Copyright (c) 2006-2007 Novell Inc.
   8 *
   9 * Please see the file Documentation/kobject.txt for critical information
  10 * about using the kobject interface.
  11 */
  12
  13#include <linux/kobject.h>
  14#include <linux/string.h>
  15#include <linux/export.h>
  16#include <linux/stat.h>
  17#include <linux/slab.h>
  18#include <linux/random.h>
  19
  20/**
  21 * kobject_namespace - return @kobj's namespace tag
  22 * @kobj: kobject in question
  23 *
  24 * Returns namespace tag of @kobj if its parent has namespace ops enabled
  25 * and thus @kobj should have a namespace tag associated with it.  Returns
  26 * %NULL otherwise.
  27 */
  28const void *kobject_namespace(struct kobject *kobj)
  29{
  30        const struct kobj_ns_type_operations *ns_ops = kobj_ns_ops(kobj);
  31
  32        if (!ns_ops || ns_ops->type == KOBJ_NS_TYPE_NONE)
  33                return NULL;
  34
  35        return kobj->ktype->namespace(kobj);
  36}
  37
  38/*
  39 * populate_dir - populate directory with attributes.
  40 * @kobj: object we're working on.
  41 *
  42 * Most subsystems have a set of default attributes that are associated
  43 * with an object that registers with them.  This is a helper called during
  44 * object registration that loops through the default attributes of the
  45 * subsystem and creates attributes files for them in sysfs.
  46 */
  47static int populate_dir(struct kobject *kobj)
  48{
  49        struct kobj_type *t = get_ktype(kobj);
  50        struct attribute *attr;
  51        int error = 0;
  52        int i;
  53
  54        if (t && t->default_attrs) {
  55                for (i = 0; (attr = t->default_attrs[i]) != NULL; i++) {
  56                        error = sysfs_create_file(kobj, attr);
  57                        if (error)
  58                                break;
  59                }
  60        }
  61        return error;
  62}
  63
  64static int create_dir(struct kobject *kobj)
  65{
  66        const struct kobj_ns_type_operations *ops;
  67        int error;
  68
  69        error = sysfs_create_dir_ns(kobj, kobject_namespace(kobj));
  70        if (error)
  71                return error;
  72
  73        error = populate_dir(kobj);
  74        if (error) {
  75                sysfs_remove_dir(kobj);
  76                return error;
  77        }
  78
  79        /*
  80         * @kobj->sd may be deleted by an ancestor going away.  Hold an
  81         * extra reference so that it stays until @kobj is gone.
  82         */
  83        sysfs_get(kobj->sd);
  84
  85        /*
  86         * If @kobj has ns_ops, its children need to be filtered based on
  87         * their namespace tags.  Enable namespace support on @kobj->sd.
  88         */
  89        ops = kobj_child_ns_ops(kobj);
  90        if (ops) {
  91                BUG_ON(ops->type <= KOBJ_NS_TYPE_NONE);
  92                BUG_ON(ops->type >= KOBJ_NS_TYPES);
  93                BUG_ON(!kobj_ns_type_registered(ops->type));
  94
  95                sysfs_enable_ns(kobj->sd);
  96        }
  97
  98        return 0;
  99}
 100
 101static int get_kobj_path_length(struct kobject *kobj)
 102{
 103        int length = 1;
 104        struct kobject *parent = kobj;
 105
 106        /* walk up the ancestors until we hit the one pointing to the
 107         * root.
 108         * Add 1 to strlen for leading '/' of each level.
 109         */
 110        do {
 111                if (kobject_name(parent) == NULL)
 112                        return 0;
 113                length += strlen(kobject_name(parent)) + 1;
 114                parent = parent->parent;
 115        } while (parent);
 116        return length;
 117}
 118
 119static void fill_kobj_path(struct kobject *kobj, char *path, int length)
 120{
 121        struct kobject *parent;
 122
 123        --length;
 124        for (parent = kobj; parent; parent = parent->parent) {
 125                int cur = strlen(kobject_name(parent));
 126                /* back up enough to print this name with '/' */
 127                length -= cur;
 128                memcpy(path + length, kobject_name(parent), cur);
 129                *(path + --length) = '/';
 130        }
 131
 132        pr_debug("kobject: '%s' (%p): %s: path = '%s'\n", kobject_name(kobj),
 133                 kobj, __func__, path);
 134}
 135
 136/**
 137 * kobject_get_path - generate and return the path associated with a given kobj and kset pair.
 138 *
 139 * @kobj:       kobject in question, with which to build the path
 140 * @gfp_mask:   the allocation type used to allocate the path
 141 *
 142 * The result must be freed by the caller with kfree().
 143 */
 144char *kobject_get_path(struct kobject *kobj, gfp_t gfp_mask)
 145{
 146        char *path;
 147        int len;
 148
 149        len = get_kobj_path_length(kobj);
 150        if (len == 0)
 151                return NULL;
 152        path = kzalloc(len, gfp_mask);
 153        if (!path)
 154                return NULL;
 155        fill_kobj_path(kobj, path, len);
 156
 157        return path;
 158}
 159EXPORT_SYMBOL_GPL(kobject_get_path);
 160
 161/* add the kobject to its kset's list */
 162static void kobj_kset_join(struct kobject *kobj)
 163{
 164        if (!kobj->kset)
 165                return;
 166
 167        kset_get(kobj->kset);
 168        spin_lock(&kobj->kset->list_lock);
 169        list_add_tail(&kobj->entry, &kobj->kset->list);
 170        spin_unlock(&kobj->kset->list_lock);
 171}
 172
 173/* remove the kobject from its kset's list */
 174static void kobj_kset_leave(struct kobject *kobj)
 175{
 176        if (!kobj->kset)
 177                return;
 178
 179        spin_lock(&kobj->kset->list_lock);
 180        list_del_init(&kobj->entry);
 181        spin_unlock(&kobj->kset->list_lock);
 182        kset_put(kobj->kset);
 183}
 184
 185static void kobject_init_internal(struct kobject *kobj)
 186{
 187        if (!kobj)
 188                return;
 189        kref_init(&kobj->kref);
 190        INIT_LIST_HEAD(&kobj->entry);
 191        kobj->state_in_sysfs = 0;
 192        kobj->state_add_uevent_sent = 0;
 193        kobj->state_remove_uevent_sent = 0;
 194        kobj->state_initialized = 1;
 195}
 196
 197
 198static int kobject_add_internal(struct kobject *kobj)
 199{
 200        int error = 0;
 201        struct kobject *parent;
 202
 203        if (!kobj)
 204                return -ENOENT;
 205
 206        if (!kobj->name || !kobj->name[0]) {
 207                WARN(1,
 208                     "kobject: (%p): attempted to be registered with empty name!\n",
 209                     kobj);
 210                return -EINVAL;
 211        }
 212
 213        parent = kobject_get(kobj->parent);
 214
 215        /* join kset if set, use it as parent if we do not already have one */
 216        if (kobj->kset) {
 217                if (!parent)
 218                        parent = kobject_get(&kobj->kset->kobj);
 219                kobj_kset_join(kobj);
 220                kobj->parent = parent;
 221        }
 222
 223        pr_debug("kobject: '%s' (%p): %s: parent: '%s', set: '%s'\n",
 224                 kobject_name(kobj), kobj, __func__,
 225                 parent ? kobject_name(parent) : "<NULL>",
 226                 kobj->kset ? kobject_name(&kobj->kset->kobj) : "<NULL>");
 227
 228        error = create_dir(kobj);
 229        if (error) {
 230                kobj_kset_leave(kobj);
 231                kobject_put(parent);
 232                kobj->parent = NULL;
 233
 234                /* be noisy on error issues */
 235                if (error == -EEXIST)
 236                        pr_err("%s failed for %s with -EEXIST, don't try to register things with the same name in the same directory.\n",
 237                               __func__, kobject_name(kobj));
 238                else
 239                        pr_err("%s failed for %s (error: %d parent: %s)\n",
 240                               __func__, kobject_name(kobj), error,
 241                               parent ? kobject_name(parent) : "'none'");
 242        } else
 243                kobj->state_in_sysfs = 1;
 244
 245        return error;
 246}
 247
 248/**
 249 * kobject_set_name_vargs - Set the name of an kobject
 250 * @kobj: struct kobject to set the name of
 251 * @fmt: format string used to build the name
 252 * @vargs: vargs to format the string.
 253 */
 254int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
 255                                  va_list vargs)
 256{
 257        const char *s;
 258
 259        if (kobj->name && !fmt)
 260                return 0;
 261
 262        s = kvasprintf_const(GFP_KERNEL, fmt, vargs);
 263        if (!s)
 264                return -ENOMEM;
 265
 266        /*
 267         * ewww... some of these buggers have '/' in the name ... If
 268         * that's the case, we need to make sure we have an actual
 269         * allocated copy to modify, since kvasprintf_const may have
 270         * returned something from .rodata.
 271         */
 272        if (strchr(s, '/')) {
 273                char *t;
 274
 275                t = kstrdup(s, GFP_KERNEL);
 276                kfree_const(s);
 277                if (!t)
 278                        return -ENOMEM;
 279                strreplace(t, '/', '!');
 280                s = t;
 281        }
 282        kfree_const(kobj->name);
 283        kobj->name = s;
 284
 285        return 0;
 286}
 287
 288/**
 289 * kobject_set_name - Set the name of a kobject
 290 * @kobj: struct kobject to set the name of
 291 * @fmt: format string used to build the name
 292 *
 293 * This sets the name of the kobject.  If you have already added the
 294 * kobject to the system, you must call kobject_rename() in order to
 295 * change the name of the kobject.
 296 */
 297int kobject_set_name(struct kobject *kobj, const char *fmt, ...)
 298{
 299        va_list vargs;
 300        int retval;
 301
 302        va_start(vargs, fmt);
 303        retval = kobject_set_name_vargs(kobj, fmt, vargs);
 304        va_end(vargs);
 305
 306        return retval;
 307}
 308EXPORT_SYMBOL(kobject_set_name);
 309
 310/**
 311 * kobject_init - initialize a kobject structure
 312 * @kobj: pointer to the kobject to initialize
 313 * @ktype: pointer to the ktype for this kobject.
 314 *
 315 * This function will properly initialize a kobject such that it can then
 316 * be passed to the kobject_add() call.
 317 *
 318 * After this function is called, the kobject MUST be cleaned up by a call
 319 * to kobject_put(), not by a call to kfree directly to ensure that all of
 320 * the memory is cleaned up properly.
 321 */
 322void kobject_init(struct kobject *kobj, struct kobj_type *ktype)
 323{
 324        char *err_str;
 325
 326        if (!kobj) {
 327                err_str = "invalid kobject pointer!";
 328                goto error;
 329        }
 330        if (!ktype) {
 331                err_str = "must have a ktype to be initialized properly!\n";
 332                goto error;
 333        }
 334        if (kobj->state_initialized) {
 335                /* do not error out as sometimes we can recover */
 336                pr_err("kobject (%p): tried to init an initialized object, something is seriously wrong.\n",
 337                       kobj);
 338                dump_stack();
 339        }
 340
 341        kobject_init_internal(kobj);
 342        kobj->ktype = ktype;
 343        return;
 344
 345error:
 346        pr_err("kobject (%p): %s\n", kobj, err_str);
 347        dump_stack();
 348}
 349EXPORT_SYMBOL(kobject_init);
 350
 351static __printf(3, 0) int kobject_add_varg(struct kobject *kobj,
 352                                           struct kobject *parent,
 353                                           const char *fmt, va_list vargs)
 354{
 355        int retval;
 356
 357        retval = kobject_set_name_vargs(kobj, fmt, vargs);
 358        if (retval) {
 359                pr_err("kobject: can not set name properly!\n");
 360                return retval;
 361        }
 362        kobj->parent = parent;
 363        return kobject_add_internal(kobj);
 364}
 365
 366/**
 367 * kobject_add - the main kobject add function
 368 * @kobj: the kobject to add
 369 * @parent: pointer to the parent of the kobject.
 370 * @fmt: format to name the kobject with.
 371 *
 372 * The kobject name is set and added to the kobject hierarchy in this
 373 * function.
 374 *
 375 * If @parent is set, then the parent of the @kobj will be set to it.
 376 * If @parent is NULL, then the parent of the @kobj will be set to the
 377 * kobject associated with the kset assigned to this kobject.  If no kset
 378 * is assigned to the kobject, then the kobject will be located in the
 379 * root of the sysfs tree.
 380 *
 381 * If this function returns an error, kobject_put() must be called to
 382 * properly clean up the memory associated with the object.
 383 * Under no instance should the kobject that is passed to this function
 384 * be directly freed with a call to kfree(), that can leak memory.
 385 *
 386 * Note, no "add" uevent will be created with this call, the caller should set
 387 * up all of the necessary sysfs files for the object and then call
 388 * kobject_uevent() with the UEVENT_ADD parameter to ensure that
 389 * userspace is properly notified of this kobject's creation.
 390 */
 391int kobject_add(struct kobject *kobj, struct kobject *parent,
 392                const char *fmt, ...)
 393{
 394        va_list args;
 395        int retval;
 396
 397        if (!kobj)
 398                return -EINVAL;
 399
 400        if (!kobj->state_initialized) {
 401                pr_err("kobject '%s' (%p): tried to add an uninitialized object, something is seriously wrong.\n",
 402                       kobject_name(kobj), kobj);
 403                dump_stack();
 404                return -EINVAL;
 405        }
 406        va_start(args, fmt);
 407        retval = kobject_add_varg(kobj, parent, fmt, args);
 408        va_end(args);
 409
 410        return retval;
 411}
 412EXPORT_SYMBOL(kobject_add);
 413
 414/**
 415 * kobject_init_and_add - initialize a kobject structure and add it to the kobject hierarchy
 416 * @kobj: pointer to the kobject to initialize
 417 * @ktype: pointer to the ktype for this kobject.
 418 * @parent: pointer to the parent of this kobject.
 419 * @fmt: the name of the kobject.
 420 *
 421 * This function combines the call to kobject_init() and
 422 * kobject_add().  The same type of error handling after a call to
 423 * kobject_add() and kobject lifetime rules are the same here.
 424 */
 425int kobject_init_and_add(struct kobject *kobj, struct kobj_type *ktype,
 426                         struct kobject *parent, const char *fmt, ...)
 427{
 428        va_list args;
 429        int retval;
 430
 431        kobject_init(kobj, ktype);
 432
 433        va_start(args, fmt);
 434        retval = kobject_add_varg(kobj, parent, fmt, args);
 435        va_end(args);
 436
 437        return retval;
 438}
 439EXPORT_SYMBOL_GPL(kobject_init_and_add);
 440
 441/**
 442 * kobject_rename - change the name of an object
 443 * @kobj: object in question.
 444 * @new_name: object's new name
 445 *
 446 * It is the responsibility of the caller to provide mutual
 447 * exclusion between two different calls of kobject_rename
 448 * on the same kobject and to ensure that new_name is valid and
 449 * won't conflict with other kobjects.
 450 */
 451int kobject_rename(struct kobject *kobj, const char *new_name)
 452{
 453        int error = 0;
 454        const char *devpath = NULL;
 455        const char *dup_name = NULL, *name;
 456        char *devpath_string = NULL;
 457        char *envp[2];
 458
 459        kobj = kobject_get(kobj);
 460        if (!kobj)
 461                return -EINVAL;
 462        if (!kobj->parent)
 463                return -EINVAL;
 464
 465        devpath = kobject_get_path(kobj, GFP_KERNEL);
 466        if (!devpath) {
 467                error = -ENOMEM;
 468                goto out;
 469        }
 470        devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
 471        if (!devpath_string) {
 472                error = -ENOMEM;
 473                goto out;
 474        }
 475        sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
 476        envp[0] = devpath_string;
 477        envp[1] = NULL;
 478
 479        name = dup_name = kstrdup_const(new_name, GFP_KERNEL);
 480        if (!name) {
 481                error = -ENOMEM;
 482                goto out;
 483        }
 484
 485        error = sysfs_rename_dir_ns(kobj, new_name, kobject_namespace(kobj));
 486        if (error)
 487                goto out;
 488
 489        /* Install the new kobject name */
 490        dup_name = kobj->name;
 491        kobj->name = name;
 492
 493        /* This function is mostly/only used for network interface.
 494         * Some hotplug package track interfaces by their name and
 495         * therefore want to know when the name is changed by the user. */
 496        kobject_uevent_env(kobj, KOBJ_MOVE, envp);
 497
 498out:
 499        kfree_const(dup_name);
 500        kfree(devpath_string);
 501        kfree(devpath);
 502        kobject_put(kobj);
 503
 504        return error;
 505}
 506EXPORT_SYMBOL_GPL(kobject_rename);
 507
 508/**
 509 * kobject_move - move object to another parent
 510 * @kobj: object in question.
 511 * @new_parent: object's new parent (can be NULL)
 512 */
 513int kobject_move(struct kobject *kobj, struct kobject *new_parent)
 514{
 515        int error;
 516        struct kobject *old_parent;
 517        const char *devpath = NULL;
 518        char *devpath_string = NULL;
 519        char *envp[2];
 520
 521        kobj = kobject_get(kobj);
 522        if (!kobj)
 523                return -EINVAL;
 524        new_parent = kobject_get(new_parent);
 525        if (!new_parent) {
 526                if (kobj->kset)
 527                        new_parent = kobject_get(&kobj->kset->kobj);
 528        }
 529
 530        /* old object path */
 531        devpath = kobject_get_path(kobj, GFP_KERNEL);
 532        if (!devpath) {
 533                error = -ENOMEM;
 534                goto out;
 535        }
 536        devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
 537        if (!devpath_string) {
 538                error = -ENOMEM;
 539                goto out;
 540        }
 541        sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
 542        envp[0] = devpath_string;
 543        envp[1] = NULL;
 544        error = sysfs_move_dir_ns(kobj, new_parent, kobject_namespace(kobj));
 545        if (error)
 546                goto out;
 547        old_parent = kobj->parent;
 548        kobj->parent = new_parent;
 549        new_parent = NULL;
 550        kobject_put(old_parent);
 551        kobject_uevent_env(kobj, KOBJ_MOVE, envp);
 552out:
 553        kobject_put(new_parent);
 554        kobject_put(kobj);
 555        kfree(devpath_string);
 556        kfree(devpath);
 557        return error;
 558}
 559EXPORT_SYMBOL_GPL(kobject_move);
 560
 561/**
 562 * kobject_del - unlink kobject from hierarchy.
 563 * @kobj: object.
 564 */
 565void kobject_del(struct kobject *kobj)
 566{
 567        struct kernfs_node *sd;
 568
 569        if (!kobj)
 570                return;
 571
 572        sd = kobj->sd;
 573        sysfs_remove_dir(kobj);
 574        sysfs_put(sd);
 575
 576        kobj->state_in_sysfs = 0;
 577        kobj_kset_leave(kobj);
 578        kobject_put(kobj->parent);
 579        kobj->parent = NULL;
 580}
 581EXPORT_SYMBOL(kobject_del);
 582
 583/**
 584 * kobject_get - increment refcount for object.
 585 * @kobj: object.
 586 */
 587struct kobject *kobject_get(struct kobject *kobj)
 588{
 589        if (kobj) {
 590                if (!kobj->state_initialized)
 591                        WARN(1, KERN_WARNING
 592                                "kobject: '%s' (%p): is not initialized, yet kobject_get() is being called.\n",
 593                             kobject_name(kobj), kobj);
 594                kref_get(&kobj->kref);
 595        }
 596        return kobj;
 597}
 598EXPORT_SYMBOL(kobject_get);
 599
 600struct kobject * __must_check kobject_get_unless_zero(struct kobject *kobj)
 601{
 602        if (!kobj)
 603                return NULL;
 604        if (!kref_get_unless_zero(&kobj->kref))
 605                kobj = NULL;
 606        return kobj;
 607}
 608EXPORT_SYMBOL(kobject_get_unless_zero);
 609
 610/*
 611 * kobject_cleanup - free kobject resources.
 612 * @kobj: object to cleanup
 613 */
 614static void kobject_cleanup(struct kobject *kobj)
 615{
 616        struct kobj_type *t = get_ktype(kobj);
 617        const char *name = kobj->name;
 618
 619        pr_debug("kobject: '%s' (%p): %s, parent %p\n",
 620                 kobject_name(kobj), kobj, __func__, kobj->parent);
 621
 622        if (t && !t->release)
 623                pr_debug("kobject: '%s' (%p): does not have a release() function, it is broken and must be fixed.\n",
 624                         kobject_name(kobj), kobj);
 625
 626        /* send "remove" if the caller did not do it but sent "add" */
 627        if (kobj->state_add_uevent_sent && !kobj->state_remove_uevent_sent) {
 628                pr_debug("kobject: '%s' (%p): auto cleanup 'remove' event\n",
 629                         kobject_name(kobj), kobj);
 630                kobject_uevent(kobj, KOBJ_REMOVE);
 631        }
 632
 633        /* remove from sysfs if the caller did not do it */
 634        if (kobj->state_in_sysfs) {
 635                pr_debug("kobject: '%s' (%p): auto cleanup kobject_del\n",
 636                         kobject_name(kobj), kobj);
 637                kobject_del(kobj);
 638        }
 639
 640        if (t && t->release) {
 641                pr_debug("kobject: '%s' (%p): calling ktype release\n",
 642                         kobject_name(kobj), kobj);
 643                t->release(kobj);
 644        }
 645
 646        /* free name if we allocated it */
 647        if (name) {
 648                pr_debug("kobject: '%s': free name\n", name);
 649                kfree_const(name);
 650        }
 651}
 652
 653#ifdef CONFIG_DEBUG_KOBJECT_RELEASE
 654static void kobject_delayed_cleanup(struct work_struct *work)
 655{
 656        kobject_cleanup(container_of(to_delayed_work(work),
 657                                     struct kobject, release));
 658}
 659#endif
 660
 661static void kobject_release(struct kref *kref)
 662{
 663        struct kobject *kobj = container_of(kref, struct kobject, kref);
 664#ifdef CONFIG_DEBUG_KOBJECT_RELEASE
 665        unsigned long delay = HZ + HZ * (get_random_int() & 0x3);
 666        pr_info("kobject: '%s' (%p): %s, parent %p (delayed %ld)\n",
 667                 kobject_name(kobj), kobj, __func__, kobj->parent, delay);
 668        INIT_DELAYED_WORK(&kobj->release, kobject_delayed_cleanup);
 669
 670        schedule_delayed_work(&kobj->release, delay);
 671#else
 672        kobject_cleanup(kobj);
 673#endif
 674}
 675
 676/**
 677 * kobject_put - decrement refcount for object.
 678 * @kobj: object.
 679 *
 680 * Decrement the refcount, and if 0, call kobject_cleanup().
 681 */
 682void kobject_put(struct kobject *kobj)
 683{
 684        if (kobj) {
 685                if (!kobj->state_initialized)
 686                        WARN(1, KERN_WARNING
 687                                "kobject: '%s' (%p): is not initialized, yet kobject_put() is being called.\n",
 688                             kobject_name(kobj), kobj);
 689                kref_put(&kobj->kref, kobject_release);
 690        }
 691}
 692EXPORT_SYMBOL(kobject_put);
 693
 694static void dynamic_kobj_release(struct kobject *kobj)
 695{
 696        pr_debug("kobject: (%p): %s\n", kobj, __func__);
 697        kfree(kobj);
 698}
 699
 700static struct kobj_type dynamic_kobj_ktype = {
 701        .release        = dynamic_kobj_release,
 702        .sysfs_ops      = &kobj_sysfs_ops,
 703};
 704
 705/**
 706 * kobject_create - create a struct kobject dynamically
 707 *
 708 * This function creates a kobject structure dynamically and sets it up
 709 * to be a "dynamic" kobject with a default release function set up.
 710 *
 711 * If the kobject was not able to be created, NULL will be returned.
 712 * The kobject structure returned from here must be cleaned up with a
 713 * call to kobject_put() and not kfree(), as kobject_init() has
 714 * already been called on this structure.
 715 */
 716struct kobject *kobject_create(void)
 717{
 718        struct kobject *kobj;
 719
 720        kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
 721        if (!kobj)
 722                return NULL;
 723
 724        kobject_init(kobj, &dynamic_kobj_ktype);
 725        return kobj;
 726}
 727
 728/**
 729 * kobject_create_and_add - create a struct kobject dynamically and register it with sysfs
 730 *
 731 * @name: the name for the kobject
 732 * @parent: the parent kobject of this kobject, if any.
 733 *
 734 * This function creates a kobject structure dynamically and registers it
 735 * with sysfs.  When you are finished with this structure, call
 736 * kobject_put() and the structure will be dynamically freed when
 737 * it is no longer being used.
 738 *
 739 * If the kobject was not able to be created, NULL will be returned.
 740 */
 741struct kobject *kobject_create_and_add(const char *name, struct kobject *parent)
 742{
 743        struct kobject *kobj;
 744        int retval;
 745
 746        kobj = kobject_create();
 747        if (!kobj)
 748                return NULL;
 749
 750        retval = kobject_add(kobj, parent, "%s", name);
 751        if (retval) {
 752                pr_warn("%s: kobject_add error: %d\n", __func__, retval);
 753                kobject_put(kobj);
 754                kobj = NULL;
 755        }
 756        return kobj;
 757}
 758EXPORT_SYMBOL_GPL(kobject_create_and_add);
 759
 760/**
 761 * kset_init - initialize a kset for use
 762 * @k: kset
 763 */
 764void kset_init(struct kset *k)
 765{
 766        kobject_init_internal(&k->kobj);
 767        INIT_LIST_HEAD(&k->list);
 768        spin_lock_init(&k->list_lock);
 769}
 770
 771/* default kobject attribute operations */
 772static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr,
 773                              char *buf)
 774{
 775        struct kobj_attribute *kattr;
 776        ssize_t ret = -EIO;
 777
 778        kattr = container_of(attr, struct kobj_attribute, attr);
 779        if (kattr->show)
 780                ret = kattr->show(kobj, kattr, buf);
 781        return ret;
 782}
 783
 784static ssize_t kobj_attr_store(struct kobject *kobj, struct attribute *attr,
 785                               const char *buf, size_t count)
 786{
 787        struct kobj_attribute *kattr;
 788        ssize_t ret = -EIO;
 789
 790        kattr = container_of(attr, struct kobj_attribute, attr);
 791        if (kattr->store)
 792                ret = kattr->store(kobj, kattr, buf, count);
 793        return ret;
 794}
 795
 796const struct sysfs_ops kobj_sysfs_ops = {
 797        .show   = kobj_attr_show,
 798        .store  = kobj_attr_store,
 799};
 800EXPORT_SYMBOL_GPL(kobj_sysfs_ops);
 801
 802/**
 803 * kset_register - initialize and add a kset.
 804 * @k: kset.
 805 */
 806int kset_register(struct kset *k)
 807{
 808        int err;
 809
 810        if (!k)
 811                return -EINVAL;
 812
 813        kset_init(k);
 814        err = kobject_add_internal(&k->kobj);
 815        if (err)
 816                return err;
 817        kobject_uevent(&k->kobj, KOBJ_ADD);
 818        return 0;
 819}
 820EXPORT_SYMBOL(kset_register);
 821
 822/**
 823 * kset_unregister - remove a kset.
 824 * @k: kset.
 825 */
 826void kset_unregister(struct kset *k)
 827{
 828        if (!k)
 829                return;
 830        kobject_del(&k->kobj);
 831        kobject_put(&k->kobj);
 832}
 833EXPORT_SYMBOL(kset_unregister);
 834
 835/**
 836 * kset_find_obj - search for object in kset.
 837 * @kset: kset we're looking in.
 838 * @name: object's name.
 839 *
 840 * Lock kset via @kset->subsys, and iterate over @kset->list,
 841 * looking for a matching kobject. If matching object is found
 842 * take a reference and return the object.
 843 */
 844struct kobject *kset_find_obj(struct kset *kset, const char *name)
 845{
 846        struct kobject *k;
 847        struct kobject *ret = NULL;
 848
 849        spin_lock(&kset->list_lock);
 850
 851        list_for_each_entry(k, &kset->list, entry) {
 852                if (kobject_name(k) && !strcmp(kobject_name(k), name)) {
 853                        ret = kobject_get_unless_zero(k);
 854                        break;
 855                }
 856        }
 857
 858        spin_unlock(&kset->list_lock);
 859        return ret;
 860}
 861EXPORT_SYMBOL_GPL(kset_find_obj);
 862
 863static void kset_release(struct kobject *kobj)
 864{
 865        struct kset *kset = container_of(kobj, struct kset, kobj);
 866        pr_debug("kobject: '%s' (%p): %s\n",
 867                 kobject_name(kobj), kobj, __func__);
 868        kfree(kset);
 869}
 870
 871static struct kobj_type kset_ktype = {
 872        .sysfs_ops      = &kobj_sysfs_ops,
 873        .release = kset_release,
 874};
 875
 876/**
 877 * kset_create - create a struct kset dynamically
 878 *
 879 * @name: the name for the kset
 880 * @uevent_ops: a struct kset_uevent_ops for the kset
 881 * @parent_kobj: the parent kobject of this kset, if any.
 882 *
 883 * This function creates a kset structure dynamically.  This structure can
 884 * then be registered with the system and show up in sysfs with a call to
 885 * kset_register().  When you are finished with this structure, if
 886 * kset_register() has been called, call kset_unregister() and the
 887 * structure will be dynamically freed when it is no longer being used.
 888 *
 889 * If the kset was not able to be created, NULL will be returned.
 890 */
 891static struct kset *kset_create(const char *name,
 892                                const struct kset_uevent_ops *uevent_ops,
 893                                struct kobject *parent_kobj)
 894{
 895        struct kset *kset;
 896        int retval;
 897
 898        kset = kzalloc(sizeof(*kset), GFP_KERNEL);
 899        if (!kset)
 900                return NULL;
 901        retval = kobject_set_name(&kset->kobj, "%s", name);
 902        if (retval) {
 903                kfree(kset);
 904                return NULL;
 905        }
 906        kset->uevent_ops = uevent_ops;
 907        kset->kobj.parent = parent_kobj;
 908
 909        /*
 910         * The kobject of this kset will have a type of kset_ktype and belong to
 911         * no kset itself.  That way we can properly free it when it is
 912         * finished being used.
 913         */
 914        kset->kobj.ktype = &kset_ktype;
 915        kset->kobj.kset = NULL;
 916
 917        return kset;
 918}
 919
 920/**
 921 * kset_create_and_add - create a struct kset dynamically and add it to sysfs
 922 *
 923 * @name: the name for the kset
 924 * @uevent_ops: a struct kset_uevent_ops for the kset
 925 * @parent_kobj: the parent kobject of this kset, if any.
 926 *
 927 * This function creates a kset structure dynamically and registers it
 928 * with sysfs.  When you are finished with this structure, call
 929 * kset_unregister() and the structure will be dynamically freed when it
 930 * is no longer being used.
 931 *
 932 * If the kset was not able to be created, NULL will be returned.
 933 */
 934struct kset *kset_create_and_add(const char *name,
 935                                 const struct kset_uevent_ops *uevent_ops,
 936                                 struct kobject *parent_kobj)
 937{
 938        struct kset *kset;
 939        int error;
 940
 941        kset = kset_create(name, uevent_ops, parent_kobj);
 942        if (!kset)
 943                return NULL;
 944        error = kset_register(kset);
 945        if (error) {
 946                kfree(kset);
 947                return NULL;
 948        }
 949        return kset;
 950}
 951EXPORT_SYMBOL_GPL(kset_create_and_add);
 952
 953
 954static DEFINE_SPINLOCK(kobj_ns_type_lock);
 955static const struct kobj_ns_type_operations *kobj_ns_ops_tbl[KOBJ_NS_TYPES];
 956
 957int kobj_ns_type_register(const struct kobj_ns_type_operations *ops)
 958{
 959        enum kobj_ns_type type = ops->type;
 960        int error;
 961
 962        spin_lock(&kobj_ns_type_lock);
 963
 964        error = -EINVAL;
 965        if (type >= KOBJ_NS_TYPES)
 966                goto out;
 967
 968        error = -EINVAL;
 969        if (type <= KOBJ_NS_TYPE_NONE)
 970                goto out;
 971
 972        error = -EBUSY;
 973        if (kobj_ns_ops_tbl[type])
 974                goto out;
 975
 976        error = 0;
 977        kobj_ns_ops_tbl[type] = ops;
 978
 979out:
 980        spin_unlock(&kobj_ns_type_lock);
 981        return error;
 982}
 983
 984int kobj_ns_type_registered(enum kobj_ns_type type)
 985{
 986        int registered = 0;
 987
 988        spin_lock(&kobj_ns_type_lock);
 989        if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES))
 990                registered = kobj_ns_ops_tbl[type] != NULL;
 991        spin_unlock(&kobj_ns_type_lock);
 992
 993        return registered;
 994}
 995
 996const struct kobj_ns_type_operations *kobj_child_ns_ops(struct kobject *parent)
 997{
 998        const struct kobj_ns_type_operations *ops = NULL;
 999
1000        if (parent && parent->ktype && parent->ktype->child_ns_type)
1001                ops = parent->ktype->child_ns_type(parent);
1002
1003        return ops;
1004}
1005
1006const struct kobj_ns_type_operations *kobj_ns_ops(struct kobject *kobj)
1007{
1008        return kobj_child_ns_ops(kobj->parent);
1009}
1010
1011bool kobj_ns_current_may_mount(enum kobj_ns_type type)
1012{
1013        bool may_mount = true;
1014
1015        spin_lock(&kobj_ns_type_lock);
1016        if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1017            kobj_ns_ops_tbl[type])
1018                may_mount = kobj_ns_ops_tbl[type]->current_may_mount();
1019        spin_unlock(&kobj_ns_type_lock);
1020
1021        return may_mount;
1022}
1023
1024void *kobj_ns_grab_current(enum kobj_ns_type type)
1025{
1026        void *ns = NULL;
1027
1028        spin_lock(&kobj_ns_type_lock);
1029        if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1030            kobj_ns_ops_tbl[type])
1031                ns = kobj_ns_ops_tbl[type]->grab_current_ns();
1032        spin_unlock(&kobj_ns_type_lock);
1033
1034        return ns;
1035}
1036EXPORT_SYMBOL_GPL(kobj_ns_grab_current);
1037
1038const void *kobj_ns_netlink(enum kobj_ns_type type, struct sock *sk)
1039{
1040        const void *ns = NULL;
1041
1042        spin_lock(&kobj_ns_type_lock);
1043        if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1044            kobj_ns_ops_tbl[type])
1045                ns = kobj_ns_ops_tbl[type]->netlink_ns(sk);
1046        spin_unlock(&kobj_ns_type_lock);
1047
1048        return ns;
1049}
1050
1051const void *kobj_ns_initial(enum kobj_ns_type type)
1052{
1053        const void *ns = NULL;
1054
1055        spin_lock(&kobj_ns_type_lock);
1056        if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1057            kobj_ns_ops_tbl[type])
1058                ns = kobj_ns_ops_tbl[type]->initial_ns();
1059        spin_unlock(&kobj_ns_type_lock);
1060
1061        return ns;
1062}
1063
1064void kobj_ns_drop(enum kobj_ns_type type, void *ns)
1065{
1066        spin_lock(&kobj_ns_type_lock);
1067        if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1068            kobj_ns_ops_tbl[type] && kobj_ns_ops_tbl[type]->drop_ns)
1069                kobj_ns_ops_tbl[type]->drop_ns(ns);
1070        spin_unlock(&kobj_ns_type_lock);
1071}
1072EXPORT_SYMBOL_GPL(kobj_ns_drop);
1073