1 /* 2 * dir.c - Operations for sysfs directories. 3 */ 4 5 #undef DEBUG 6 7 #include <linux/fs.h> 8 #include <linux/mount.h> 9 #include <linux/module.h> 10 #include <linux/kobject.h> 11 #include <linux/namei.h> 12 #include <asm/semaphore.h> 13 #include "sysfs.h" 14 15 DECLARE_RWSEM(sysfs_rename_sem); 16 17 static void sysfs_d_iput(struct dentry * dentry, struct inode * inode) 18 { 19 struct sysfs_dirent * sd = dentry->d_fsdata; 20 21 if (sd) { 22 BUG_ON(sd->s_dentry != dentry); 23 sd->s_dentry = NULL; 24 sysfs_put(sd); 25 } 26 iput(inode); 27 } 28 29 static struct dentry_operations sysfs_dentry_ops = { 30 .d_iput = sysfs_d_iput, 31 }; 32 33 /* 34 * Allocates a new sysfs_dirent and links it to the parent sysfs_dirent 35 */ 36 static struct sysfs_dirent * __sysfs_new_dirent(void * element) 37 { 38 struct sysfs_dirent * sd; 39 40 sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL); 41 if (!sd) 42 return NULL; 43 44 atomic_set(&sd->s_count, 1); 45 atomic_set(&sd->s_event, 1); 46 INIT_LIST_HEAD(&sd->s_children); 47 INIT_LIST_HEAD(&sd->s_sibling); 48 sd->s_element = element; 49 50 return sd; 51 } 52 53 static void __sysfs_list_dirent(struct sysfs_dirent *parent_sd, 54 struct sysfs_dirent *sd) 55 { 56 if (sd) 57 list_add(&sd->s_sibling, &parent_sd->s_children); 58 } 59 60 static struct sysfs_dirent * sysfs_new_dirent(struct sysfs_dirent *parent_sd, 61 void * element) 62 { 63 struct sysfs_dirent *sd; 64 sd = __sysfs_new_dirent(element); 65 __sysfs_list_dirent(parent_sd, sd); 66 return sd; 67 } 68 69 /* 70 * 71 * Return -EEXIST if there is already a sysfs element with the same name for 72 * the same parent. 73 * 74 * called with parent inode's i_mutex held 75 */ 76 int sysfs_dirent_exist(struct sysfs_dirent *parent_sd, 77 const unsigned char *new) 78 { 79 struct sysfs_dirent * sd; 80 81 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { 82 if (sd->s_element) { 83 const unsigned char *existing = sysfs_get_name(sd); 84 if (strcmp(existing, new)) 85 continue; 86 else 87 return -EEXIST; 88 } 89 } 90 91 return 0; 92 } 93 94 95 static struct sysfs_dirent * 96 __sysfs_make_dirent(struct dentry *dentry, void *element, mode_t mode, int type) 97 { 98 struct sysfs_dirent * sd; 99 100 sd = __sysfs_new_dirent(element); 101 if (!sd) 102 goto out; 103 104 sd->s_mode = mode; 105 sd->s_type = type; 106 sd->s_dentry = dentry; 107 if (dentry) { 108 dentry->d_fsdata = sysfs_get(sd); 109 dentry->d_op = &sysfs_dentry_ops; 110 } 111 112 out: 113 return sd; 114 } 115 116 int sysfs_make_dirent(struct sysfs_dirent * parent_sd, struct dentry * dentry, 117 void * element, umode_t mode, int type) 118 { 119 struct sysfs_dirent *sd; 120 121 sd = __sysfs_make_dirent(dentry, element, mode, type); 122 __sysfs_list_dirent(parent_sd, sd); 123 124 return sd ? 0 : -ENOMEM; 125 } 126 127 static int init_dir(struct inode * inode) 128 { 129 inode->i_op = &sysfs_dir_inode_operations; 130 inode->i_fop = &sysfs_dir_operations; 131 132 /* directory inodes start off with i_nlink == 2 (for "." entry) */ 133 inc_nlink(inode); 134 return 0; 135 } 136 137 static int init_file(struct inode * inode) 138 { 139 inode->i_size = PAGE_SIZE; 140 inode->i_fop = &sysfs_file_operations; 141 return 0; 142 } 143 144 static int init_symlink(struct inode * inode) 145 { 146 inode->i_op = &sysfs_symlink_inode_operations; 147 return 0; 148 } 149 150 static int create_dir(struct kobject * k, struct dentry * p, 151 const char * n, struct dentry ** d) 152 { 153 int error; 154 umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO; 155 156 mutex_lock(&p->d_inode->i_mutex); 157 *d = lookup_one_len(n, p, strlen(n)); 158 if (!IS_ERR(*d)) { 159 if (sysfs_dirent_exist(p->d_fsdata, n)) 160 error = -EEXIST; 161 else 162 error = sysfs_make_dirent(p->d_fsdata, *d, k, mode, 163 SYSFS_DIR); 164 if (!error) { 165 error = sysfs_create(*d, mode, init_dir); 166 if (!error) { 167 inc_nlink(p->d_inode); 168 (*d)->d_op = &sysfs_dentry_ops; 169 d_rehash(*d); 170 } 171 } 172 if (error && (error != -EEXIST)) { 173 struct sysfs_dirent *sd = (*d)->d_fsdata; 174 if (sd) { 175 list_del_init(&sd->s_sibling); 176 sysfs_put(sd); 177 } 178 d_drop(*d); 179 } 180 dput(*d); 181 } else 182 error = PTR_ERR(*d); 183 mutex_unlock(&p->d_inode->i_mutex); 184 return error; 185 } 186 187 188 int sysfs_create_subdir(struct kobject * k, const char * n, struct dentry ** d) 189 { 190 return create_dir(k,k->dentry,n,d); 191 } 192 193 /** 194 * sysfs_create_dir - create a directory for an object. 195 * @kobj: object we're creating directory for. 196 * @shadow_parent: parent parent object. 197 */ 198 199 int sysfs_create_dir(struct kobject * kobj, struct dentry *shadow_parent) 200 { 201 struct dentry * dentry = NULL; 202 struct dentry * parent; 203 int error = 0; 204 205 BUG_ON(!kobj); 206 207 if (shadow_parent) 208 parent = shadow_parent; 209 else if (kobj->parent) 210 parent = kobj->parent->dentry; 211 else if (sysfs_mount && sysfs_mount->mnt_sb) 212 parent = sysfs_mount->mnt_sb->s_root; 213 else 214 return -EFAULT; 215 216 error = create_dir(kobj,parent,kobject_name(kobj),&dentry); 217 if (!error) 218 kobj->dentry = dentry; 219 return error; 220 } 221 222 /* attaches attribute's sysfs_dirent to the dentry corresponding to the 223 * attribute file 224 */ 225 static int sysfs_attach_attr(struct sysfs_dirent * sd, struct dentry * dentry) 226 { 227 struct attribute * attr = NULL; 228 struct bin_attribute * bin_attr = NULL; 229 int (* init) (struct inode *) = NULL; 230 int error = 0; 231 232 if (sd->s_type & SYSFS_KOBJ_BIN_ATTR) { 233 bin_attr = sd->s_element; 234 attr = &bin_attr->attr; 235 } else { 236 attr = sd->s_element; 237 init = init_file; 238 } 239 240 dentry->d_fsdata = sysfs_get(sd); 241 sd->s_dentry = dentry; 242 error = sysfs_create(dentry, (attr->mode & S_IALLUGO) | S_IFREG, init); 243 if (error) { 244 sysfs_put(sd); 245 return error; 246 } 247 248 if (bin_attr) { 249 dentry->d_inode->i_size = bin_attr->size; 250 dentry->d_inode->i_fop = &bin_fops; 251 } 252 dentry->d_op = &sysfs_dentry_ops; 253 d_rehash(dentry); 254 255 return 0; 256 } 257 258 static int sysfs_attach_link(struct sysfs_dirent * sd, struct dentry * dentry) 259 { 260 int err = 0; 261 262 dentry->d_fsdata = sysfs_get(sd); 263 sd->s_dentry = dentry; 264 err = sysfs_create(dentry, S_IFLNK|S_IRWXUGO, init_symlink); 265 if (!err) { 266 dentry->d_op = &sysfs_dentry_ops; 267 d_rehash(dentry); 268 } else 269 sysfs_put(sd); 270 271 return err; 272 } 273 274 static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry, 275 struct nameidata *nd) 276 { 277 struct sysfs_dirent * parent_sd = dentry->d_parent->d_fsdata; 278 struct sysfs_dirent * sd; 279 int err = 0; 280 281 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { 282 if (sd->s_type & SYSFS_NOT_PINNED) { 283 const unsigned char * name = sysfs_get_name(sd); 284 285 if (strcmp(name, dentry->d_name.name)) 286 continue; 287 288 if (sd->s_type & SYSFS_KOBJ_LINK) 289 err = sysfs_attach_link(sd, dentry); 290 else 291 err = sysfs_attach_attr(sd, dentry); 292 break; 293 } 294 } 295 296 return ERR_PTR(err); 297 } 298 299 struct inode_operations sysfs_dir_inode_operations = { 300 .lookup = sysfs_lookup, 301 .setattr = sysfs_setattr, 302 }; 303 304 static void remove_dir(struct dentry * d) 305 { 306 struct dentry * parent = dget(d->d_parent); 307 struct sysfs_dirent * sd; 308 309 mutex_lock(&parent->d_inode->i_mutex); 310 d_delete(d); 311 sd = d->d_fsdata; 312 list_del_init(&sd->s_sibling); 313 sysfs_put(sd); 314 if (d->d_inode) 315 simple_rmdir(parent->d_inode,d); 316 317 pr_debug(" o %s removing done (%d)\n",d->d_name.name, 318 atomic_read(&d->d_count)); 319 320 mutex_unlock(&parent->d_inode->i_mutex); 321 dput(parent); 322 } 323 324 void sysfs_remove_subdir(struct dentry * d) 325 { 326 remove_dir(d); 327 } 328 329 330 static void __sysfs_remove_dir(struct dentry *dentry) 331 { 332 struct sysfs_dirent * parent_sd; 333 struct sysfs_dirent * sd, * tmp; 334 335 dget(dentry); 336 if (!dentry) 337 return; 338 339 pr_debug("sysfs %s: removing dir\n",dentry->d_name.name); 340 mutex_lock(&dentry->d_inode->i_mutex); 341 parent_sd = dentry->d_fsdata; 342 list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) { 343 if (!sd->s_element || !(sd->s_type & SYSFS_NOT_PINNED)) 344 continue; 345 list_del_init(&sd->s_sibling); 346 sysfs_drop_dentry(sd, dentry); 347 sysfs_put(sd); 348 } 349 mutex_unlock(&dentry->d_inode->i_mutex); 350 351 remove_dir(dentry); 352 /** 353 * Drop reference from dget() on entrance. 354 */ 355 dput(dentry); 356 } 357 358 /** 359 * sysfs_remove_dir - remove an object's directory. 360 * @kobj: object. 361 * 362 * The only thing special about this is that we remove any files in 363 * the directory before we remove the directory, and we've inlined 364 * what used to be sysfs_rmdir() below, instead of calling separately. 365 */ 366 367 void sysfs_remove_dir(struct kobject * kobj) 368 { 369 __sysfs_remove_dir(kobj->dentry); 370 kobj->dentry = NULL; 371 } 372 373 int sysfs_rename_dir(struct kobject * kobj, struct dentry *new_parent, 374 const char *new_name) 375 { 376 int error = 0; 377 struct dentry * new_dentry; 378 379 if (!new_parent) 380 return -EFAULT; 381 382 down_write(&sysfs_rename_sem); 383 mutex_lock(&new_parent->d_inode->i_mutex); 384 385 new_dentry = lookup_one_len(new_name, new_parent, strlen(new_name)); 386 if (!IS_ERR(new_dentry)) { 387 /* By allowing two different directories with the 388 * same d_parent we allow this routine to move 389 * between different shadows of the same directory 390 */ 391 if (kobj->dentry->d_parent->d_inode != new_parent->d_inode) 392 return -EINVAL; 393 else if (new_dentry->d_parent->d_inode != new_parent->d_inode) 394 error = -EINVAL; 395 else if (new_dentry == kobj->dentry) 396 error = -EINVAL; 397 else if (!new_dentry->d_inode) { 398 error = kobject_set_name(kobj, "%s", new_name); 399 if (!error) { 400 struct sysfs_dirent *sd, *parent_sd; 401 402 d_add(new_dentry, NULL); 403 d_move(kobj->dentry, new_dentry); 404 405 sd = kobj->dentry->d_fsdata; 406 parent_sd = new_parent->d_fsdata; 407 408 list_del_init(&sd->s_sibling); 409 list_add(&sd->s_sibling, &parent_sd->s_children); 410 } 411 else 412 d_drop(new_dentry); 413 } else 414 error = -EEXIST; 415 dput(new_dentry); 416 } 417 mutex_unlock(&new_parent->d_inode->i_mutex); 418 up_write(&sysfs_rename_sem); 419 420 return error; 421 } 422 423 int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent) 424 { 425 struct dentry *old_parent_dentry, *new_parent_dentry, *new_dentry; 426 struct sysfs_dirent *new_parent_sd, *sd; 427 int error; 428 429 old_parent_dentry = kobj->parent ? 430 kobj->parent->dentry : sysfs_mount->mnt_sb->s_root; 431 new_parent_dentry = new_parent ? 432 new_parent->dentry : sysfs_mount->mnt_sb->s_root; 433 434 again: 435 mutex_lock(&old_parent_dentry->d_inode->i_mutex); 436 if (!mutex_trylock(&new_parent_dentry->d_inode->i_mutex)) { 437 mutex_unlock(&old_parent_dentry->d_inode->i_mutex); 438 goto again; 439 } 440 441 new_parent_sd = new_parent_dentry->d_fsdata; 442 sd = kobj->dentry->d_fsdata; 443 444 new_dentry = lookup_one_len(kobj->name, new_parent_dentry, 445 strlen(kobj->name)); 446 if (IS_ERR(new_dentry)) { 447 error = PTR_ERR(new_dentry); 448 goto out; 449 } else 450 error = 0; 451 d_add(new_dentry, NULL); 452 d_move(kobj->dentry, new_dentry); 453 dput(new_dentry); 454 455 /* Remove from old parent's list and insert into new parent's list. */ 456 list_del_init(&sd->s_sibling); 457 list_add(&sd->s_sibling, &new_parent_sd->s_children); 458 459 out: 460 mutex_unlock(&new_parent_dentry->d_inode->i_mutex); 461 mutex_unlock(&old_parent_dentry->d_inode->i_mutex); 462 463 return error; 464 } 465 466 static int sysfs_dir_open(struct inode *inode, struct file *file) 467 { 468 struct dentry * dentry = file->f_path.dentry; 469 struct sysfs_dirent * parent_sd = dentry->d_fsdata; 470 471 mutex_lock(&dentry->d_inode->i_mutex); 472 file->private_data = sysfs_new_dirent(parent_sd, NULL); 473 mutex_unlock(&dentry->d_inode->i_mutex); 474 475 return file->private_data ? 0 : -ENOMEM; 476 477 } 478 479 static int sysfs_dir_close(struct inode *inode, struct file *file) 480 { 481 struct dentry * dentry = file->f_path.dentry; 482 struct sysfs_dirent * cursor = file->private_data; 483 484 mutex_lock(&dentry->d_inode->i_mutex); 485 list_del_init(&cursor->s_sibling); 486 mutex_unlock(&dentry->d_inode->i_mutex); 487 488 release_sysfs_dirent(cursor); 489 490 return 0; 491 } 492 493 /* Relationship between s_mode and the DT_xxx types */ 494 static inline unsigned char dt_type(struct sysfs_dirent *sd) 495 { 496 return (sd->s_mode >> 12) & 15; 497 } 498 499 static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir) 500 { 501 struct dentry *dentry = filp->f_path.dentry; 502 struct sysfs_dirent * parent_sd = dentry->d_fsdata; 503 struct sysfs_dirent *cursor = filp->private_data; 504 struct list_head *p, *q = &cursor->s_sibling; 505 ino_t ino; 506 int i = filp->f_pos; 507 508 switch (i) { 509 case 0: 510 ino = dentry->d_inode->i_ino; 511 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0) 512 break; 513 filp->f_pos++; 514 i++; 515 /* fallthrough */ 516 case 1: 517 ino = parent_ino(dentry); 518 if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0) 519 break; 520 filp->f_pos++; 521 i++; 522 /* fallthrough */ 523 default: 524 if (filp->f_pos == 2) 525 list_move(q, &parent_sd->s_children); 526 527 for (p=q->next; p!= &parent_sd->s_children; p=p->next) { 528 struct sysfs_dirent *next; 529 const char * name; 530 int len; 531 532 next = list_entry(p, struct sysfs_dirent, 533 s_sibling); 534 if (!next->s_element) 535 continue; 536 537 name = sysfs_get_name(next); 538 len = strlen(name); 539 if (next->s_dentry) 540 ino = next->s_dentry->d_inode->i_ino; 541 else 542 ino = iunique(sysfs_sb, 2); 543 544 if (filldir(dirent, name, len, filp->f_pos, ino, 545 dt_type(next)) < 0) 546 return 0; 547 548 list_move(q, p); 549 p = q; 550 filp->f_pos++; 551 } 552 } 553 return 0; 554 } 555 556 static loff_t sysfs_dir_lseek(struct file * file, loff_t offset, int origin) 557 { 558 struct dentry * dentry = file->f_path.dentry; 559 560 mutex_lock(&dentry->d_inode->i_mutex); 561 switch (origin) { 562 case 1: 563 offset += file->f_pos; 564 case 0: 565 if (offset >= 0) 566 break; 567 default: 568 mutex_unlock(&file->f_path.dentry->d_inode->i_mutex); 569 return -EINVAL; 570 } 571 if (offset != file->f_pos) { 572 file->f_pos = offset; 573 if (file->f_pos >= 2) { 574 struct sysfs_dirent *sd = dentry->d_fsdata; 575 struct sysfs_dirent *cursor = file->private_data; 576 struct list_head *p; 577 loff_t n = file->f_pos - 2; 578 579 list_del(&cursor->s_sibling); 580 p = sd->s_children.next; 581 while (n && p != &sd->s_children) { 582 struct sysfs_dirent *next; 583 next = list_entry(p, struct sysfs_dirent, 584 s_sibling); 585 if (next->s_element) 586 n--; 587 p = p->next; 588 } 589 list_add_tail(&cursor->s_sibling, p); 590 } 591 } 592 mutex_unlock(&dentry->d_inode->i_mutex); 593 return offset; 594 } 595 596 597 /** 598 * sysfs_make_shadowed_dir - Setup so a directory can be shadowed 599 * @kobj: object we're creating shadow of. 600 */ 601 602 int sysfs_make_shadowed_dir(struct kobject *kobj, 603 void * (*follow_link)(struct dentry *, struct nameidata *)) 604 { 605 struct inode *inode; 606 struct inode_operations *i_op; 607 608 inode = kobj->dentry->d_inode; 609 if (inode->i_op != &sysfs_dir_inode_operations) 610 return -EINVAL; 611 612 i_op = kmalloc(sizeof(*i_op), GFP_KERNEL); 613 if (!i_op) 614 return -ENOMEM; 615 616 memcpy(i_op, &sysfs_dir_inode_operations, sizeof(*i_op)); 617 i_op->follow_link = follow_link; 618 619 /* Locking of inode->i_op? 620 * Since setting i_op is a single word write and they 621 * are atomic we should be ok here. 622 */ 623 inode->i_op = i_op; 624 return 0; 625 } 626 627 /** 628 * sysfs_create_shadow_dir - create a shadow directory for an object. 629 * @kobj: object we're creating directory for. 630 * 631 * sysfs_make_shadowed_dir must already have been called on this 632 * directory. 633 */ 634 635 struct dentry *sysfs_create_shadow_dir(struct kobject *kobj) 636 { 637 struct sysfs_dirent *sd; 638 struct dentry *parent, *dir, *shadow; 639 struct inode *inode; 640 641 dir = kobj->dentry; 642 inode = dir->d_inode; 643 parent = dir->d_parent; 644 shadow = ERR_PTR(-EINVAL); 645 if (!sysfs_is_shadowed_inode(inode)) 646 goto out; 647 648 shadow = d_alloc(parent, &dir->d_name); 649 if (!shadow) 650 goto nomem; 651 652 sd = __sysfs_make_dirent(shadow, kobj, inode->i_mode, SYSFS_DIR); 653 if (!sd) 654 goto nomem; 655 656 d_instantiate(shadow, igrab(inode)); 657 inc_nlink(inode); 658 inc_nlink(parent->d_inode); 659 shadow->d_op = &sysfs_dentry_ops; 660 661 dget(shadow); /* Extra count - pin the dentry in core */ 662 663 out: 664 return shadow; 665 nomem: 666 dput(shadow); 667 shadow = ERR_PTR(-ENOMEM); 668 goto out; 669 } 670 671 /** 672 * sysfs_remove_shadow_dir - remove an object's directory. 673 * @shadow: dentry of shadow directory 674 * 675 * The only thing special about this is that we remove any files in 676 * the directory before we remove the directory, and we've inlined 677 * what used to be sysfs_rmdir() below, instead of calling separately. 678 */ 679 680 void sysfs_remove_shadow_dir(struct dentry *shadow) 681 { 682 __sysfs_remove_dir(shadow); 683 } 684 685 const struct file_operations sysfs_dir_operations = { 686 .open = sysfs_dir_open, 687 .release = sysfs_dir_close, 688 .llseek = sysfs_dir_lseek, 689 .read = generic_read_dir, 690 .readdir = sysfs_readdir, 691 }; 692