1/* 2 * fs/sysfs/dir.c - sysfs core and dir operation implementation 3 * 4 * Copyright (c) 2001-3 Patrick Mochel 5 * Copyright (c) 2007 SUSE Linux Products GmbH 6 * Copyright (c) 2007 Tejun Heo <teheo@suse.de> 7 * 8 * This file is released under the GPLv2. 9 * 10 * Please see Documentation/filesystems/sysfs.txt for more information. 11 */ 12 13#undef DEBUG 14 15#include <linux/fs.h> 16#include <linux/mount.h> 17#include <linux/module.h> 18#include <linux/kobject.h> 19#include <linux/namei.h> 20#include <linux/idr.h> 21#include <linux/completion.h> 22#include <linux/mutex.h> 23#include <linux/slab.h> 24#include <linux/security.h> 25#include "sysfs.h" 26 27DEFINE_MUTEX(sysfs_mutex); 28DEFINE_SPINLOCK(sysfs_assoc_lock); 29 30static DEFINE_SPINLOCK(sysfs_ino_lock); 31static DEFINE_IDA(sysfs_ino_ida); 32 33/** 34 * sysfs_link_sibling - link sysfs_dirent into sibling list 35 * @sd: sysfs_dirent of interest 36 * 37 * Link @sd into its sibling list which starts from 38 * sd->s_parent->s_dir.children. 39 * 40 * Locking: 41 * mutex_lock(sysfs_mutex) 42 */ 43static void sysfs_link_sibling(struct sysfs_dirent *sd) 44{ 45 struct sysfs_dirent *parent_sd = sd->s_parent; 46 struct sysfs_dirent **pos; 47 48 BUG_ON(sd->s_sibling); 49 50 /* Store directory entries in order by ino. This allows 51 * readdir to properly restart without having to add a 52 * cursor into the s_dir.children list. 53 */ 54 for (pos = &parent_sd->s_dir.children; *pos; pos = &(*pos)->s_sibling) { 55 if (sd->s_ino < (*pos)->s_ino) 56 break; 57 } 58 sd->s_sibling = *pos; 59 *pos = sd; 60} 61 62/** 63 * sysfs_unlink_sibling - unlink sysfs_dirent from sibling list 64 * @sd: sysfs_dirent of interest 65 * 66 * Unlink @sd from its sibling list which starts from 67 * sd->s_parent->s_dir.children. 68 * 69 * Locking: 70 * mutex_lock(sysfs_mutex) 71 */ 72static void sysfs_unlink_sibling(struct sysfs_dirent *sd) 73{ 74 struct sysfs_dirent **pos; 75 76 for (pos = &sd->s_parent->s_dir.children; *pos; 77 pos = &(*pos)->s_sibling) { 78 if (*pos == sd) { 79 *pos = sd->s_sibling; 80 sd->s_sibling = NULL; 81 break; 82 } 83 } 84} 85 86/** 87 * sysfs_get_active - get an active reference to sysfs_dirent 88 * @sd: sysfs_dirent to get an active reference to 89 * 90 * Get an active reference of @sd. This function is noop if @sd 91 * is NULL. 92 * 93 * RETURNS: 94 * Pointer to @sd on success, NULL on failure. 95 */ 96struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd) 97{ 98 if (unlikely(!sd)) 99 return NULL; 100 101 while (1) { 102 int v, t; 103 104 v = atomic_read(&sd->s_active); 105 if (unlikely(v < 0)) 106 return NULL; 107 108 t = atomic_cmpxchg(&sd->s_active, v, v + 1); 109 if (likely(t == v)) { 110 rwsem_acquire_read(&sd->dep_map, 0, 1, _RET_IP_); 111 return sd; 112 } 113 if (t < 0) 114 return NULL; 115 116 cpu_relax(); 117 } 118} 119 120/** 121 * sysfs_put_active - put an active reference to sysfs_dirent 122 * @sd: sysfs_dirent to put an active reference to 123 * 124 * Put an active reference to @sd. This function is noop if @sd 125 * is NULL. 126 */ 127void sysfs_put_active(struct sysfs_dirent *sd) 128{ 129 struct completion *cmpl; 130 int v; 131 132 if (unlikely(!sd)) 133 return; 134 135 rwsem_release(&sd->dep_map, 1, _RET_IP_); 136 v = atomic_dec_return(&sd->s_active); 137 if (likely(v != SD_DEACTIVATED_BIAS)) 138 return; 139 140 /* atomic_dec_return() is a mb(), we'll always see the updated 141 * sd->s_sibling. 142 */ 143 cmpl = (void *)sd->s_sibling; 144 complete(cmpl); 145} 146 147/** 148 * sysfs_deactivate - deactivate sysfs_dirent 149 * @sd: sysfs_dirent to deactivate 150 * 151 * Deny new active references and drain existing ones. 152 */ 153static void sysfs_deactivate(struct sysfs_dirent *sd) 154{ 155 DECLARE_COMPLETION_ONSTACK(wait); 156 int v; 157 158 BUG_ON(sd->s_sibling || !(sd->s_flags & SYSFS_FLAG_REMOVED)); 159 160 if (!(sysfs_type(sd) & SYSFS_ACTIVE_REF)) 161 return; 162 163 sd->s_sibling = (void *)&wait; 164 165 rwsem_acquire(&sd->dep_map, 0, 0, _RET_IP_); 166 /* atomic_add_return() is a mb(), put_active() will always see 167 * the updated sd->s_sibling. 168 */ 169 v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active); 170 171 if (v != SD_DEACTIVATED_BIAS) { 172 lock_contended(&sd->dep_map, _RET_IP_); 173 wait_for_completion(&wait); 174 } 175 176 sd->s_sibling = NULL; 177 178 lock_acquired(&sd->dep_map, _RET_IP_); 179 rwsem_release(&sd->dep_map, 1, _RET_IP_); 180} 181 182static int sysfs_alloc_ino(ino_t *pino) 183{ 184 int ino, rc; 185 186 retry: 187 spin_lock(&sysfs_ino_lock); 188 rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino); 189 spin_unlock(&sysfs_ino_lock); 190 191 if (rc == -EAGAIN) { 192 if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL)) 193 goto retry; 194 rc = -ENOMEM; 195 } 196 197 *pino = ino; 198 return rc; 199} 200 201static void sysfs_free_ino(ino_t ino) 202{ 203 spin_lock(&sysfs_ino_lock); 204 ida_remove(&sysfs_ino_ida, ino); 205 spin_unlock(&sysfs_ino_lock); 206} 207 208void release_sysfs_dirent(struct sysfs_dirent * sd) 209{ 210 struct sysfs_dirent *parent_sd; 211 212 repeat: 213 /* Moving/renaming is always done while holding reference. 214 * sd->s_parent won't change beneath us. 215 */ 216 parent_sd = sd->s_parent; 217 218 if (sysfs_type(sd) == SYSFS_KOBJ_LINK) 219 sysfs_put(sd->s_symlink.target_sd); 220 if (sysfs_type(sd) & SYSFS_COPY_NAME) 221 kfree(sd->s_name); 222 if (sd->s_iattr && sd->s_iattr->ia_secdata) 223 security_release_secctx(sd->s_iattr->ia_secdata, 224 sd->s_iattr->ia_secdata_len); 225 kfree(sd->s_iattr); 226 sysfs_free_ino(sd->s_ino); 227 kmem_cache_free(sysfs_dir_cachep, sd); 228 229 sd = parent_sd; 230 if (sd && atomic_dec_and_test(&sd->s_count)) 231 goto repeat; 232} 233 234static int sysfs_dentry_delete(struct dentry *dentry) 235{ 236 struct sysfs_dirent *sd = dentry->d_fsdata; 237 return !!(sd->s_flags & SYSFS_FLAG_REMOVED); 238} 239 240static int sysfs_dentry_revalidate(struct dentry *dentry, struct nameidata *nd) 241{ 242 struct sysfs_dirent *sd = dentry->d_fsdata; 243 int is_dir; 244 245 mutex_lock(&sysfs_mutex); 246 247 /* The sysfs dirent has been deleted */ 248 if (sd->s_flags & SYSFS_FLAG_REMOVED) 249 goto out_bad; 250 251 /* The sysfs dirent has been moved? */ 252 if (dentry->d_parent->d_fsdata != sd->s_parent) 253 goto out_bad; 254 255 /* The sysfs dirent has been renamed */ 256 if (strcmp(dentry->d_name.name, sd->s_name) != 0) 257 goto out_bad; 258 259 mutex_unlock(&sysfs_mutex); 260out_valid: 261 return 1; 262out_bad: 263 /* Remove the dentry from the dcache hashes. 264 * If this is a deleted dentry we use d_drop instead of d_delete 265 * so sysfs doesn't need to cope with negative dentries. 266 * 267 * If this is a dentry that has simply been renamed we 268 * use d_drop to remove it from the dcache lookup on its 269 * old parent. If this dentry persists later when a lookup 270 * is performed at its new name the dentry will be readded 271 * to the dcache hashes. 272 */ 273 is_dir = (sysfs_type(sd) == SYSFS_DIR); 274 mutex_unlock(&sysfs_mutex); 275 if (is_dir) { 276 /* If we have submounts we must allow the vfs caches 277 * to lie about the state of the filesystem to prevent 278 * leaks and other nasty things. 279 */ 280 if (have_submounts(dentry)) 281 goto out_valid; 282 shrink_dcache_parent(dentry); 283 } 284 d_drop(dentry); 285 return 0; 286} 287 288static void sysfs_dentry_iput(struct dentry *dentry, struct inode *inode) 289{ 290 struct sysfs_dirent * sd = dentry->d_fsdata; 291 292 sysfs_put(sd); 293 iput(inode); 294} 295 296static const struct dentry_operations sysfs_dentry_ops = { 297 .d_revalidate = sysfs_dentry_revalidate, 298 .d_delete = sysfs_dentry_delete, 299 .d_iput = sysfs_dentry_iput, 300}; 301 302struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type) 303{ 304 char *dup_name = NULL; 305 struct sysfs_dirent *sd; 306 307 if (type & SYSFS_COPY_NAME) { 308 name = dup_name = kstrdup(name, GFP_KERNEL); 309 if (!name) 310 return NULL; 311 } 312 313 sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL); 314 if (!sd) 315 goto err_out1; 316 317 if (sysfs_alloc_ino(&sd->s_ino)) 318 goto err_out2; 319 320 atomic_set(&sd->s_count, 1); 321 atomic_set(&sd->s_active, 0); 322 323 sd->s_name = name; 324 sd->s_mode = mode; 325 sd->s_flags = type; 326 327 return sd; 328 329 err_out2: 330 kmem_cache_free(sysfs_dir_cachep, sd); 331 err_out1: 332 kfree(dup_name); 333 return NULL; 334} 335 336/** 337 * sysfs_addrm_start - prepare for sysfs_dirent add/remove 338 * @acxt: pointer to sysfs_addrm_cxt to be used 339 * @parent_sd: parent sysfs_dirent 340 * 341 * This function is called when the caller is about to add or 342 * remove sysfs_dirent under @parent_sd. This function acquires 343 * sysfs_mutex. @acxt is used to keep and pass context to 344 * other addrm functions. 345 * 346 * LOCKING: 347 * Kernel thread context (may sleep). sysfs_mutex is locked on 348 * return. 349 */ 350void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt, 351 struct sysfs_dirent *parent_sd) 352{ 353 memset(acxt, 0, sizeof(*acxt)); 354 acxt->parent_sd = parent_sd; 355 356 mutex_lock(&sysfs_mutex); 357} 358 359/** 360 * __sysfs_add_one - add sysfs_dirent to parent without warning 361 * @acxt: addrm context to use 362 * @sd: sysfs_dirent to be added 363 * 364 * Get @acxt->parent_sd and set sd->s_parent to it and increment 365 * nlink of parent inode if @sd is a directory and link into the 366 * children list of the parent. 367 * 368 * This function should be called between calls to 369 * sysfs_addrm_start() and sysfs_addrm_finish() and should be 370 * passed the same @acxt as passed to sysfs_addrm_start(). 371 * 372 * LOCKING: 373 * Determined by sysfs_addrm_start(). 374 * 375 * RETURNS: 376 * 0 on success, -EEXIST if entry with the given name already 377 * exists. 378 */ 379int __sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) 380{ 381 struct sysfs_inode_attrs *ps_iattr; 382 383 if (sysfs_find_dirent(acxt->parent_sd, sd->s_ns, sd->s_name)) 384 return -EEXIST; 385 386 sd->s_parent = sysfs_get(acxt->parent_sd); 387 388 sysfs_link_sibling(sd); 389 390 /* Update timestamps on the parent */ 391 ps_iattr = acxt->parent_sd->s_iattr; 392 if (ps_iattr) { 393 struct iattr *ps_iattrs = &ps_iattr->ia_iattr; 394 ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME; 395 } 396 397 return 0; 398} 399 400static char *sysfs_pathname(struct sysfs_dirent *sd, char *path) 401{ 402 if (sd->s_parent) { 403 sysfs_pathname(sd->s_parent, path); 404 strcat(path, "/"); 405 } 406 strcat(path, sd->s_name); 407 return path; 408} 409 410/** 411 * sysfs_add_one - add sysfs_dirent to parent 412 * @acxt: addrm context to use 413 * @sd: sysfs_dirent to be added 414 * 415 * Get @acxt->parent_sd and set sd->s_parent to it and increment 416 * nlink of parent inode if @sd is a directory and link into the 417 * children list of the parent. 418 * 419 * This function should be called between calls to 420 * sysfs_addrm_start() and sysfs_addrm_finish() and should be 421 * passed the same @acxt as passed to sysfs_addrm_start(). 422 * 423 * LOCKING: 424 * Determined by sysfs_addrm_start(). 425 * 426 * RETURNS: 427 * 0 on success, -EEXIST if entry with the given name already 428 * exists. 429 */ 430int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) 431{ 432 int ret; 433 434 ret = __sysfs_add_one(acxt, sd); 435 if (ret == -EEXIST) { 436 char *path = kzalloc(PATH_MAX, GFP_KERNEL); 437 WARN(1, KERN_WARNING 438 "sysfs: cannot create duplicate filename '%s'\n", 439 (path == NULL) ? sd->s_name : 440 strcat(strcat(sysfs_pathname(acxt->parent_sd, path), "/"), 441 sd->s_name)); 442 kfree(path); 443 } 444 445 return ret; 446} 447 448/** 449 * sysfs_remove_one - remove sysfs_dirent from parent 450 * @acxt: addrm context to use 451 * @sd: sysfs_dirent to be removed 452 * 453 * Mark @sd removed and drop nlink of parent inode if @sd is a 454 * directory. @sd is unlinked from the children list. 455 * 456 * This function should be called between calls to 457 * sysfs_addrm_start() and sysfs_addrm_finish() and should be 458 * passed the same @acxt as passed to sysfs_addrm_start(). 459 * 460 * LOCKING: 461 * Determined by sysfs_addrm_start(). 462 */ 463void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) 464{ 465 struct sysfs_inode_attrs *ps_iattr; 466 467 BUG_ON(sd->s_flags & SYSFS_FLAG_REMOVED); 468 469 sysfs_unlink_sibling(sd); 470 471 /* Update timestamps on the parent */ 472 ps_iattr = acxt->parent_sd->s_iattr; 473 if (ps_iattr) { 474 struct iattr *ps_iattrs = &ps_iattr->ia_iattr; 475 ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME; 476 } 477 478 sd->s_flags |= SYSFS_FLAG_REMOVED; 479 sd->s_sibling = acxt->removed; 480 acxt->removed = sd; 481} 482 483/** 484 * sysfs_addrm_finish - finish up sysfs_dirent add/remove 485 * @acxt: addrm context to finish up 486 * 487 * Finish up sysfs_dirent add/remove. Resources acquired by 488 * sysfs_addrm_start() are released and removed sysfs_dirents are 489 * cleaned up. 490 * 491 * LOCKING: 492 * sysfs_mutex is released. 493 */ 494void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt) 495{ 496 /* release resources acquired by sysfs_addrm_start() */ 497 mutex_unlock(&sysfs_mutex); 498 499 /* kill removed sysfs_dirents */ 500 while (acxt->removed) { 501 struct sysfs_dirent *sd = acxt->removed; 502 503 acxt->removed = sd->s_sibling; 504 sd->s_sibling = NULL; 505 506 sysfs_deactivate(sd); 507 unmap_bin_file(sd); 508 sysfs_put(sd); 509 } 510} 511 512/** 513 * sysfs_find_dirent - find sysfs_dirent with the given name 514 * @parent_sd: sysfs_dirent to search under 515 * @name: name to look for 516 * 517 * Look for sysfs_dirent with name @name under @parent_sd. 518 * 519 * LOCKING: 520 * mutex_lock(sysfs_mutex) 521 * 522 * RETURNS: 523 * Pointer to sysfs_dirent if found, NULL if not. 524 */ 525struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd, 526 const void *ns, 527 const unsigned char *name) 528{ 529 struct sysfs_dirent *sd; 530 531 for (sd = parent_sd->s_dir.children; sd; sd = sd->s_sibling) { 532 if (ns && sd->s_ns && (sd->s_ns != ns)) 533 continue; 534 if (!strcmp(sd->s_name, name)) 535 return sd; 536 } 537 return NULL; 538} 539 540/** 541 * sysfs_get_dirent - find and get sysfs_dirent with the given name 542 * @parent_sd: sysfs_dirent to search under 543 * @name: name to look for 544 * 545 * Look for sysfs_dirent with name @name under @parent_sd and get 546 * it if found. 547 * 548 * LOCKING: 549 * Kernel thread context (may sleep). Grabs sysfs_mutex. 550 * 551 * RETURNS: 552 * Pointer to sysfs_dirent if found, NULL if not. 553 */ 554struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd, 555 const void *ns, 556 const unsigned char *name) 557{ 558 struct sysfs_dirent *sd; 559 560 mutex_lock(&sysfs_mutex); 561 sd = sysfs_find_dirent(parent_sd, ns, name); 562 sysfs_get(sd); 563 mutex_unlock(&sysfs_mutex); 564 565 return sd; 566} 567EXPORT_SYMBOL_GPL(sysfs_get_dirent); 568 569static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd, 570 enum kobj_ns_type type, const void *ns, const char *name, 571 struct sysfs_dirent **p_sd) 572{ 573 umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO; 574 struct sysfs_addrm_cxt acxt; 575 struct sysfs_dirent *sd; 576 int rc; 577 578 /* allocate */ 579 sd = sysfs_new_dirent(name, mode, SYSFS_DIR); 580 if (!sd) 581 return -ENOMEM; 582 583 sd->s_flags |= (type << SYSFS_NS_TYPE_SHIFT); 584 sd->s_ns = ns; 585 sd->s_dir.kobj = kobj; 586 587 /* link in */ 588 sysfs_addrm_start(&acxt, parent_sd); 589 rc = sysfs_add_one(&acxt, sd); 590 sysfs_addrm_finish(&acxt); 591 592 if (rc == 0) 593 *p_sd = sd; 594 else 595 sysfs_put(sd); 596 597 return rc; 598} 599 600int sysfs_create_subdir(struct kobject *kobj, const char *name, 601 struct sysfs_dirent **p_sd) 602{ 603 return create_dir(kobj, kobj->sd, 604 KOBJ_NS_TYPE_NONE, NULL, name, p_sd); 605} 606 607/** 608 * sysfs_read_ns_type: return associated ns_type 609 * @kobj: the kobject being queried 610 * 611 * Each kobject can be tagged with exactly one namespace type 612 * (i.e. network or user). Return the ns_type associated with 613 * this object if any 614 */ 615static enum kobj_ns_type sysfs_read_ns_type(struct kobject *kobj) 616{ 617 const struct kobj_ns_type_operations *ops; 618 enum kobj_ns_type type; 619 620 ops = kobj_child_ns_ops(kobj); 621 if (!ops) 622 return KOBJ_NS_TYPE_NONE; 623 624 type = ops->type; 625 BUG_ON(type <= KOBJ_NS_TYPE_NONE); 626 BUG_ON(type >= KOBJ_NS_TYPES); 627 BUG_ON(!kobj_ns_type_registered(type)); 628 629 return type; 630} 631 632/** 633 * sysfs_create_dir - create a directory for an object. 634 * @kobj: object we're creating directory for. 635 */ 636int sysfs_create_dir(struct kobject * kobj) 637{ 638 enum kobj_ns_type type; 639 struct sysfs_dirent *parent_sd, *sd; 640 const void *ns = NULL; 641 int error = 0; 642 643 BUG_ON(!kobj); 644 645 if (kobj->parent) 646 parent_sd = kobj->parent->sd; 647 else 648 parent_sd = &sysfs_root; 649 650 if (sysfs_ns_type(parent_sd)) 651 ns = kobj->ktype->namespace(kobj); 652 type = sysfs_read_ns_type(kobj); 653 654 error = create_dir(kobj, parent_sd, type, ns, kobject_name(kobj), &sd); 655 if (!error) 656 kobj->sd = sd; 657 return error; 658} 659 660static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry, 661 struct nameidata *nd) 662{ 663 struct dentry *ret = NULL; 664 struct dentry *parent = dentry->d_parent; 665 struct sysfs_dirent *parent_sd = parent->d_fsdata; 666 struct sysfs_dirent *sd; 667 struct inode *inode; 668 enum kobj_ns_type type; 669 const void *ns; 670 671 mutex_lock(&sysfs_mutex); 672 673 type = sysfs_ns_type(parent_sd); 674 ns = sysfs_info(dir->i_sb)->ns[type]; 675 676 sd = sysfs_find_dirent(parent_sd, ns, dentry->d_name.name); 677 678 /* no such entry */ 679 if (!sd) { 680 ret = ERR_PTR(-ENOENT); 681 goto out_unlock; 682 } 683 684 /* attach dentry and inode */ 685 inode = sysfs_get_inode(dir->i_sb, sd); 686 if (!inode) { 687 ret = ERR_PTR(-ENOMEM); 688 goto out_unlock; 689 } 690 691 /* instantiate and hash dentry */ 692 ret = d_find_alias(inode); 693 if (!ret) { 694 dentry->d_op = &sysfs_dentry_ops; 695 dentry->d_fsdata = sysfs_get(sd); 696 d_add(dentry, inode); 697 } else { 698 d_move(ret, dentry); 699 iput(inode); 700 } 701 702 out_unlock: 703 mutex_unlock(&sysfs_mutex); 704 return ret; 705} 706 707const struct inode_operations sysfs_dir_inode_operations = { 708 .lookup = sysfs_lookup, 709 .permission = sysfs_permission, 710 .setattr = sysfs_setattr, 711 .getattr = sysfs_getattr, 712 .setxattr = sysfs_setxattr, 713}; 714 715static void remove_dir(struct sysfs_dirent *sd) 716{ 717 struct sysfs_addrm_cxt acxt; 718 719 sysfs_addrm_start(&acxt, sd->s_parent); 720 sysfs_remove_one(&acxt, sd); 721 sysfs_addrm_finish(&acxt); 722} 723 724void sysfs_remove_subdir(struct sysfs_dirent *sd) 725{ 726 remove_dir(sd); 727} 728 729 730static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd) 731{ 732 struct sysfs_addrm_cxt acxt; 733 struct sysfs_dirent **pos; 734 735 if (!dir_sd) 736 return; 737 738 pr_debug("sysfs %s: removing dir\n", dir_sd->s_name); 739 sysfs_addrm_start(&acxt, dir_sd); 740 pos = &dir_sd->s_dir.children; 741 while (*pos) { 742 struct sysfs_dirent *sd = *pos; 743 744 if (sysfs_type(sd) != SYSFS_DIR) 745 sysfs_remove_one(&acxt, sd); 746 else 747 pos = &(*pos)->s_sibling; 748 } 749 sysfs_addrm_finish(&acxt); 750 751 remove_dir(dir_sd); 752} 753 754/** 755 * sysfs_remove_dir - remove an object's directory. 756 * @kobj: object. 757 * 758 * The only thing special about this is that we remove any files in 759 * the directory before we remove the directory, and we've inlined 760 * what used to be sysfs_rmdir() below, instead of calling separately. 761 */ 762 763void sysfs_remove_dir(struct kobject * kobj) 764{ 765 struct sysfs_dirent *sd = kobj->sd; 766 767 spin_lock(&sysfs_assoc_lock); 768 kobj->sd = NULL; 769 spin_unlock(&sysfs_assoc_lock); 770 771 __sysfs_remove_dir(sd); 772} 773 774int sysfs_rename(struct sysfs_dirent *sd, 775 struct sysfs_dirent *new_parent_sd, const void *new_ns, 776 const char *new_name) 777{ 778 const char *dup_name = NULL; 779 int error; 780 781 mutex_lock(&sysfs_mutex); 782 783 error = 0; 784 if ((sd->s_parent == new_parent_sd) && (sd->s_ns == new_ns) && 785 (strcmp(sd->s_name, new_name) == 0)) 786 goto out; /* nothing to rename */ 787 788 error = -EEXIST; 789 if (sysfs_find_dirent(new_parent_sd, new_ns, new_name)) 790 goto out; 791 792 /* rename sysfs_dirent */ 793 if (strcmp(sd->s_name, new_name) != 0) { 794 error = -ENOMEM; 795 new_name = dup_name = kstrdup(new_name, GFP_KERNEL); 796 if (!new_name) 797 goto out; 798 799 dup_name = sd->s_name; 800 sd->s_name = new_name; 801 } 802 803 /* Remove from old parent's list and insert into new parent's list. */ 804 if (sd->s_parent != new_parent_sd) { 805 sysfs_unlink_sibling(sd); 806 sysfs_get(new_parent_sd); 807 sysfs_put(sd->s_parent); 808 sd->s_parent = new_parent_sd; 809 sysfs_link_sibling(sd); 810 } 811 sd->s_ns = new_ns; 812 813 error = 0; 814 out: 815 mutex_unlock(&sysfs_mutex); 816 kfree(dup_name); 817 return error; 818} 819 820int sysfs_rename_dir(struct kobject *kobj, const char *new_name) 821{ 822 struct sysfs_dirent *parent_sd = kobj->sd->s_parent; 823 const void *new_ns = NULL; 824 825 if (sysfs_ns_type(parent_sd)) 826 new_ns = kobj->ktype->namespace(kobj); 827 828 return sysfs_rename(kobj->sd, parent_sd, new_ns, new_name); 829} 830 831int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj) 832{ 833 struct sysfs_dirent *sd = kobj->sd; 834 struct sysfs_dirent *new_parent_sd; 835 const void *new_ns = NULL; 836 837 BUG_ON(!sd->s_parent); 838 if (sysfs_ns_type(sd->s_parent)) 839 new_ns = kobj->ktype->namespace(kobj); 840 new_parent_sd = new_parent_kobj && new_parent_kobj->sd ? 841 new_parent_kobj->sd : &sysfs_root; 842 843 return sysfs_rename(sd, new_parent_sd, new_ns, sd->s_name); 844} 845 846/* Relationship between s_mode and the DT_xxx types */ 847static inline unsigned char dt_type(struct sysfs_dirent *sd) 848{ 849 return (sd->s_mode >> 12) & 15; 850} 851 852static int sysfs_dir_release(struct inode *inode, struct file *filp) 853{ 854 sysfs_put(filp->private_data); 855 return 0; 856} 857 858static struct sysfs_dirent *sysfs_dir_pos(const void *ns, 859 struct sysfs_dirent *parent_sd, ino_t ino, struct sysfs_dirent *pos) 860{ 861 if (pos) { 862 int valid = !(pos->s_flags & SYSFS_FLAG_REMOVED) && 863 pos->s_parent == parent_sd && 864 ino == pos->s_ino; 865 sysfs_put(pos); 866 if (!valid) 867 pos = NULL; 868 } 869 if (!pos && (ino > 1) && (ino < INT_MAX)) { 870 pos = parent_sd->s_dir.children; 871 while (pos && (ino > pos->s_ino)) 872 pos = pos->s_sibling; 873 } 874 while (pos && pos->s_ns && pos->s_ns != ns) 875 pos = pos->s_sibling; 876 return pos; 877} 878 879static struct sysfs_dirent *sysfs_dir_next_pos(const void *ns, 880 struct sysfs_dirent *parent_sd, ino_t ino, struct sysfs_dirent *pos) 881{ 882 pos = sysfs_dir_pos(ns, parent_sd, ino, pos); 883 if (pos) 884 pos = pos->s_sibling; 885 while (pos && pos->s_ns && pos->s_ns != ns) 886 pos = pos->s_sibling; 887 return pos; 888} 889 890static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir) 891{ 892 struct dentry *dentry = filp->f_path.dentry; 893 struct sysfs_dirent * parent_sd = dentry->d_fsdata; 894 struct sysfs_dirent *pos = filp->private_data; 895 enum kobj_ns_type type; 896 const void *ns; 897 ino_t ino; 898 899 type = sysfs_ns_type(parent_sd); 900 ns = sysfs_info(dentry->d_sb)->ns[type]; 901 902 if (filp->f_pos == 0) { 903 ino = parent_sd->s_ino; 904 if (filldir(dirent, ".", 1, filp->f_pos, ino, DT_DIR) == 0) 905 filp->f_pos++; 906 } 907 if (filp->f_pos == 1) { 908 if (parent_sd->s_parent) 909 ino = parent_sd->s_parent->s_ino; 910 else 911 ino = parent_sd->s_ino; 912 if (filldir(dirent, "..", 2, filp->f_pos, ino, DT_DIR) == 0) 913 filp->f_pos++; 914 } 915 mutex_lock(&sysfs_mutex); 916 for (pos = sysfs_dir_pos(ns, parent_sd, filp->f_pos, pos); 917 pos; 918 pos = sysfs_dir_next_pos(ns, parent_sd, filp->f_pos, pos)) { 919 const char * name; 920 unsigned int type; 921 int len, ret; 922 923 name = pos->s_name; 924 len = strlen(name); 925 ino = pos->s_ino; 926 type = dt_type(pos); 927 filp->f_pos = ino; 928 filp->private_data = sysfs_get(pos); 929 930 mutex_unlock(&sysfs_mutex); 931 ret = filldir(dirent, name, len, filp->f_pos, ino, type); 932 mutex_lock(&sysfs_mutex); 933 if (ret < 0) 934 break; 935 } 936 mutex_unlock(&sysfs_mutex); 937 if ((filp->f_pos > 1) && !pos) { /* EOF */ 938 filp->f_pos = INT_MAX; 939 filp->private_data = NULL; 940 } 941 return 0; 942} 943 944 945const struct file_operations sysfs_dir_operations = { 946 .read = generic_read_dir, 947 .readdir = sysfs_readdir, 948 .release = sysfs_dir_release, 949 .llseek = generic_file_llseek, 950}; 951