1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * proc/fs/generic.c --- generic routines for the proc-fs 4 * 5 * This file contains generic proc-fs routines for handling 6 * directories and files. 7 * 8 * Copyright (C) 1991, 1992 Linus Torvalds. 9 * Copyright (C) 1997 Theodore Ts'o 10 */ 11 12 #include <linux/cache.h> 13 #include <linux/errno.h> 14 #include <linux/time.h> 15 #include <linux/proc_fs.h> 16 #include <linux/stat.h> 17 #include <linux/mm.h> 18 #include <linux/module.h> 19 #include <linux/namei.h> 20 #include <linux/slab.h> 21 #include <linux/printk.h> 22 #include <linux/mount.h> 23 #include <linux/init.h> 24 #include <linux/idr.h> 25 #include <linux/bitops.h> 26 #include <linux/spinlock.h> 27 #include <linux/completion.h> 28 #include <linux/uaccess.h> 29 #include <linux/seq_file.h> 30 31 #include "internal.h" 32 33 static DEFINE_RWLOCK(proc_subdir_lock); 34 35 struct kmem_cache *proc_dir_entry_cache __ro_after_init; 36 37 void pde_free(struct proc_dir_entry *pde) 38 { 39 if (S_ISLNK(pde->mode)) 40 kfree(pde->data); 41 if (pde->name != pde->inline_name) 42 kfree(pde->name); 43 kmem_cache_free(proc_dir_entry_cache, pde); 44 } 45 46 static int proc_match(const char *name, struct proc_dir_entry *de, unsigned int len) 47 { 48 if (len < de->namelen) 49 return -1; 50 if (len > de->namelen) 51 return 1; 52 53 return memcmp(name, de->name, len); 54 } 55 56 static struct proc_dir_entry *pde_subdir_first(struct proc_dir_entry *dir) 57 { 58 return rb_entry_safe(rb_first(&dir->subdir), struct proc_dir_entry, 59 subdir_node); 60 } 61 62 static struct proc_dir_entry *pde_subdir_next(struct proc_dir_entry *dir) 63 { 64 return rb_entry_safe(rb_next(&dir->subdir_node), struct proc_dir_entry, 65 subdir_node); 66 } 67 68 static struct proc_dir_entry *pde_subdir_find(struct proc_dir_entry *dir, 69 const char *name, 70 unsigned int len) 71 { 72 struct rb_node *node = dir->subdir.rb_node; 73 74 while (node) { 75 struct proc_dir_entry *de = rb_entry(node, 76 struct proc_dir_entry, 77 subdir_node); 78 int result = proc_match(name, de, len); 79 80 if (result < 0) 81 node = node->rb_left; 82 else if (result > 0) 83 node = node->rb_right; 84 else 85 return de; 86 } 87 return NULL; 88 } 89 90 static bool pde_subdir_insert(struct proc_dir_entry *dir, 91 struct proc_dir_entry *de) 92 { 93 struct rb_root *root = &dir->subdir; 94 struct rb_node **new = &root->rb_node, *parent = NULL; 95 96 /* Figure out where to put new node */ 97 while (*new) { 98 struct proc_dir_entry *this = rb_entry(*new, 99 struct proc_dir_entry, 100 subdir_node); 101 int result = proc_match(de->name, this, de->namelen); 102 103 parent = *new; 104 if (result < 0) 105 new = &(*new)->rb_left; 106 else if (result > 0) 107 new = &(*new)->rb_right; 108 else 109 return false; 110 } 111 112 /* Add new node and rebalance tree. */ 113 rb_link_node(&de->subdir_node, parent, new); 114 rb_insert_color(&de->subdir_node, root); 115 return true; 116 } 117 118 static int proc_notify_change(struct mnt_idmap *idmap, 119 struct dentry *dentry, struct iattr *iattr) 120 { 121 struct inode *inode = d_inode(dentry); 122 struct proc_dir_entry *de = PDE(inode); 123 int error; 124 125 error = setattr_prepare(&nop_mnt_idmap, dentry, iattr); 126 if (error) 127 return error; 128 129 setattr_copy(&nop_mnt_idmap, inode, iattr); 130 131 proc_set_user(de, inode->i_uid, inode->i_gid); 132 de->mode = inode->i_mode; 133 return 0; 134 } 135 136 static int proc_getattr(struct mnt_idmap *idmap, 137 const struct path *path, struct kstat *stat, 138 u32 request_mask, unsigned int query_flags) 139 { 140 struct inode *inode = d_inode(path->dentry); 141 struct proc_dir_entry *de = PDE(inode); 142 if (de) { 143 nlink_t nlink = READ_ONCE(de->nlink); 144 if (nlink > 0) { 145 set_nlink(inode, nlink); 146 } 147 } 148 149 generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat); 150 return 0; 151 } 152 153 static const struct inode_operations proc_file_inode_operations = { 154 .setattr = proc_notify_change, 155 }; 156 157 /* 158 * This function parses a name such as "tty/driver/serial", and 159 * returns the struct proc_dir_entry for "/proc/tty/driver", and 160 * returns "serial" in residual. 161 */ 162 static int __xlate_proc_name(const char *name, struct proc_dir_entry **ret, 163 const char **residual) 164 { 165 const char *cp = name, *next; 166 struct proc_dir_entry *de; 167 168 de = *ret ?: &proc_root; 169 while ((next = strchr(cp, '/')) != NULL) { 170 de = pde_subdir_find(de, cp, next - cp); 171 if (!de) { 172 WARN(1, "name '%s'\n", name); 173 return -ENOENT; 174 } 175 cp = next + 1; 176 } 177 *residual = cp; 178 *ret = de; 179 return 0; 180 } 181 182 static int xlate_proc_name(const char *name, struct proc_dir_entry **ret, 183 const char **residual) 184 { 185 int rv; 186 187 read_lock(&proc_subdir_lock); 188 rv = __xlate_proc_name(name, ret, residual); 189 read_unlock(&proc_subdir_lock); 190 return rv; 191 } 192 193 static DEFINE_IDA(proc_inum_ida); 194 195 #define PROC_DYNAMIC_FIRST 0xF0000000U 196 197 /* 198 * Return an inode number between PROC_DYNAMIC_FIRST and 199 * 0xffffffff, or zero on failure. 200 */ 201 int proc_alloc_inum(unsigned int *inum) 202 { 203 int i; 204 205 i = ida_alloc_max(&proc_inum_ida, UINT_MAX - PROC_DYNAMIC_FIRST, 206 GFP_KERNEL); 207 if (i < 0) 208 return i; 209 210 *inum = PROC_DYNAMIC_FIRST + (unsigned int)i; 211 return 0; 212 } 213 214 void proc_free_inum(unsigned int inum) 215 { 216 ida_free(&proc_inum_ida, inum - PROC_DYNAMIC_FIRST); 217 } 218 219 static int proc_misc_d_revalidate(struct inode *dir, const struct qstr *name, 220 struct dentry *dentry, unsigned int flags) 221 { 222 if (flags & LOOKUP_RCU) 223 return -ECHILD; 224 225 if (atomic_read(&PDE(d_inode(dentry))->in_use) < 0) 226 return 0; /* revalidate */ 227 return 1; 228 } 229 230 static int proc_misc_d_delete(const struct dentry *dentry) 231 { 232 return atomic_read(&PDE(d_inode(dentry))->in_use) < 0; 233 } 234 235 static const struct dentry_operations proc_misc_dentry_ops = { 236 .d_revalidate = proc_misc_d_revalidate, 237 .d_delete = proc_misc_d_delete, 238 }; 239 240 /* 241 * Don't create negative dentries here, return -ENOENT by hand 242 * instead. 243 */ 244 struct dentry *proc_lookup_de(struct inode *dir, struct dentry *dentry, 245 struct proc_dir_entry *de) 246 { 247 struct inode *inode; 248 249 read_lock(&proc_subdir_lock); 250 de = pde_subdir_find(de, dentry->d_name.name, dentry->d_name.len); 251 if (de) { 252 pde_get(de); 253 read_unlock(&proc_subdir_lock); 254 inode = proc_get_inode(dir->i_sb, de); 255 if (!inode) 256 return ERR_PTR(-ENOMEM); 257 d_set_d_op(dentry, de->proc_dops); 258 return d_splice_alias(inode, dentry); 259 } 260 read_unlock(&proc_subdir_lock); 261 return ERR_PTR(-ENOENT); 262 } 263 264 struct dentry *proc_lookup(struct inode *dir, struct dentry *dentry, 265 unsigned int flags) 266 { 267 struct proc_fs_info *fs_info = proc_sb_info(dir->i_sb); 268 269 if (fs_info->pidonly == PROC_PIDONLY_ON) 270 return ERR_PTR(-ENOENT); 271 272 return proc_lookup_de(dir, dentry, PDE(dir)); 273 } 274 275 /* 276 * This returns non-zero if at EOF, so that the /proc 277 * root directory can use this and check if it should 278 * continue with the <pid> entries.. 279 * 280 * Note that the VFS-layer doesn't care about the return 281 * value of the readdir() call, as long as it's non-negative 282 * for success.. 283 */ 284 int proc_readdir_de(struct file *file, struct dir_context *ctx, 285 struct proc_dir_entry *de) 286 { 287 int i; 288 289 if (!dir_emit_dots(file, ctx)) 290 return 0; 291 292 i = ctx->pos - 2; 293 read_lock(&proc_subdir_lock); 294 de = pde_subdir_first(de); 295 for (;;) { 296 if (!de) { 297 read_unlock(&proc_subdir_lock); 298 return 0; 299 } 300 if (!i) 301 break; 302 de = pde_subdir_next(de); 303 i--; 304 } 305 306 do { 307 struct proc_dir_entry *next; 308 pde_get(de); 309 read_unlock(&proc_subdir_lock); 310 if (!dir_emit(ctx, de->name, de->namelen, 311 de->low_ino, de->mode >> 12)) { 312 pde_put(de); 313 return 0; 314 } 315 ctx->pos++; 316 read_lock(&proc_subdir_lock); 317 next = pde_subdir_next(de); 318 pde_put(de); 319 de = next; 320 } while (de); 321 read_unlock(&proc_subdir_lock); 322 return 1; 323 } 324 325 int proc_readdir(struct file *file, struct dir_context *ctx) 326 { 327 struct inode *inode = file_inode(file); 328 struct proc_fs_info *fs_info = proc_sb_info(inode->i_sb); 329 330 if (fs_info->pidonly == PROC_PIDONLY_ON) 331 return 1; 332 333 return proc_readdir_de(file, ctx, PDE(inode)); 334 } 335 336 /* 337 * These are the generic /proc directory operations. They 338 * use the in-memory "struct proc_dir_entry" tree to parse 339 * the /proc directory. 340 */ 341 static const struct file_operations proc_dir_operations = { 342 .llseek = generic_file_llseek, 343 .read = generic_read_dir, 344 .iterate_shared = proc_readdir, 345 }; 346 347 static int proc_net_d_revalidate(struct inode *dir, const struct qstr *name, 348 struct dentry *dentry, unsigned int flags) 349 { 350 return 0; 351 } 352 353 const struct dentry_operations proc_net_dentry_ops = { 354 .d_revalidate = proc_net_d_revalidate, 355 .d_delete = always_delete_dentry, 356 }; 357 358 /* 359 * proc directories can do almost nothing.. 360 */ 361 static const struct inode_operations proc_dir_inode_operations = { 362 .lookup = proc_lookup, 363 .getattr = proc_getattr, 364 .setattr = proc_notify_change, 365 }; 366 367 /* returns the registered entry, or frees dp and returns NULL on failure */ 368 struct proc_dir_entry *proc_register(struct proc_dir_entry *dir, 369 struct proc_dir_entry *dp) 370 { 371 if (proc_alloc_inum(&dp->low_ino)) 372 goto out_free_entry; 373 374 write_lock(&proc_subdir_lock); 375 dp->parent = dir; 376 if (pde_subdir_insert(dir, dp) == false) { 377 WARN(1, "proc_dir_entry '%s/%s' already registered\n", 378 dir->name, dp->name); 379 write_unlock(&proc_subdir_lock); 380 goto out_free_inum; 381 } 382 dir->nlink++; 383 write_unlock(&proc_subdir_lock); 384 385 return dp; 386 out_free_inum: 387 proc_free_inum(dp->low_ino); 388 out_free_entry: 389 pde_free(dp); 390 return NULL; 391 } 392 393 static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent, 394 const char *name, 395 umode_t mode, 396 nlink_t nlink) 397 { 398 struct proc_dir_entry *ent = NULL; 399 const char *fn; 400 struct qstr qstr; 401 402 if (xlate_proc_name(name, parent, &fn) != 0) 403 goto out; 404 qstr.name = fn; 405 qstr.len = strlen(fn); 406 if (qstr.len == 0 || qstr.len >= 256) { 407 WARN(1, "name len %u\n", qstr.len); 408 return NULL; 409 } 410 if (qstr.len == 1 && fn[0] == '.') { 411 WARN(1, "name '.'\n"); 412 return NULL; 413 } 414 if (qstr.len == 2 && fn[0] == '.' && fn[1] == '.') { 415 WARN(1, "name '..'\n"); 416 return NULL; 417 } 418 if (*parent == &proc_root && name_to_int(&qstr) != ~0U) { 419 WARN(1, "create '/proc/%s' by hand\n", qstr.name); 420 return NULL; 421 } 422 if (is_empty_pde(*parent)) { 423 WARN(1, "attempt to add to permanently empty directory"); 424 return NULL; 425 } 426 427 ent = kmem_cache_zalloc(proc_dir_entry_cache, GFP_KERNEL); 428 if (!ent) 429 goto out; 430 431 if (qstr.len + 1 <= SIZEOF_PDE_INLINE_NAME) { 432 ent->name = ent->inline_name; 433 } else { 434 ent->name = kmalloc(qstr.len + 1, GFP_KERNEL); 435 if (!ent->name) { 436 pde_free(ent); 437 return NULL; 438 } 439 } 440 441 memcpy(ent->name, fn, qstr.len + 1); 442 ent->namelen = qstr.len; 443 ent->mode = mode; 444 ent->nlink = nlink; 445 ent->subdir = RB_ROOT; 446 refcount_set(&ent->refcnt, 1); 447 spin_lock_init(&ent->pde_unload_lock); 448 INIT_LIST_HEAD(&ent->pde_openers); 449 proc_set_user(ent, (*parent)->uid, (*parent)->gid); 450 451 ent->proc_dops = &proc_misc_dentry_ops; 452 /* Revalidate everything under /proc/${pid}/net */ 453 if ((*parent)->proc_dops == &proc_net_dentry_ops) 454 pde_force_lookup(ent); 455 456 out: 457 return ent; 458 } 459 460 struct proc_dir_entry *proc_symlink(const char *name, 461 struct proc_dir_entry *parent, const char *dest) 462 { 463 struct proc_dir_entry *ent; 464 465 ent = __proc_create(&parent, name, 466 (S_IFLNK | S_IRUGO | S_IWUGO | S_IXUGO),1); 467 468 if (ent) { 469 ent->size = strlen(dest); 470 ent->data = kmemdup(dest, ent->size + 1, GFP_KERNEL); 471 if (ent->data) { 472 ent->proc_iops = &proc_link_inode_operations; 473 ent = proc_register(parent, ent); 474 } else { 475 pde_free(ent); 476 ent = NULL; 477 } 478 } 479 return ent; 480 } 481 EXPORT_SYMBOL(proc_symlink); 482 483 struct proc_dir_entry *_proc_mkdir(const char *name, umode_t mode, 484 struct proc_dir_entry *parent, void *data, bool force_lookup) 485 { 486 struct proc_dir_entry *ent; 487 488 if (mode == 0) 489 mode = S_IRUGO | S_IXUGO; 490 491 ent = __proc_create(&parent, name, S_IFDIR | mode, 2); 492 if (ent) { 493 ent->data = data; 494 ent->proc_dir_ops = &proc_dir_operations; 495 ent->proc_iops = &proc_dir_inode_operations; 496 if (force_lookup) { 497 pde_force_lookup(ent); 498 } 499 ent = proc_register(parent, ent); 500 } 501 return ent; 502 } 503 EXPORT_SYMBOL_GPL(_proc_mkdir); 504 505 struct proc_dir_entry *proc_mkdir_data(const char *name, umode_t mode, 506 struct proc_dir_entry *parent, void *data) 507 { 508 return _proc_mkdir(name, mode, parent, data, false); 509 } 510 EXPORT_SYMBOL_GPL(proc_mkdir_data); 511 512 struct proc_dir_entry *proc_mkdir_mode(const char *name, umode_t mode, 513 struct proc_dir_entry *parent) 514 { 515 return proc_mkdir_data(name, mode, parent, NULL); 516 } 517 EXPORT_SYMBOL(proc_mkdir_mode); 518 519 struct proc_dir_entry *proc_mkdir(const char *name, 520 struct proc_dir_entry *parent) 521 { 522 return proc_mkdir_data(name, 0, parent, NULL); 523 } 524 EXPORT_SYMBOL(proc_mkdir); 525 526 struct proc_dir_entry *proc_create_mount_point(const char *name) 527 { 528 umode_t mode = S_IFDIR | S_IRUGO | S_IXUGO; 529 struct proc_dir_entry *ent, *parent = NULL; 530 531 ent = __proc_create(&parent, name, mode, 2); 532 if (ent) { 533 ent->data = NULL; 534 ent->proc_dir_ops = NULL; 535 ent->proc_iops = NULL; 536 ent = proc_register(parent, ent); 537 } 538 return ent; 539 } 540 EXPORT_SYMBOL(proc_create_mount_point); 541 542 struct proc_dir_entry *proc_create_reg(const char *name, umode_t mode, 543 struct proc_dir_entry **parent, void *data) 544 { 545 struct proc_dir_entry *p; 546 547 if ((mode & S_IFMT) == 0) 548 mode |= S_IFREG; 549 if ((mode & S_IALLUGO) == 0) 550 mode |= S_IRUGO; 551 if (WARN_ON_ONCE(!S_ISREG(mode))) 552 return NULL; 553 554 p = __proc_create(parent, name, mode, 1); 555 if (p) { 556 p->proc_iops = &proc_file_inode_operations; 557 p->data = data; 558 } 559 return p; 560 } 561 562 static void pde_set_flags(struct proc_dir_entry *pde) 563 { 564 if (pde->proc_ops->proc_flags & PROC_ENTRY_PERMANENT) 565 pde->flags |= PROC_ENTRY_PERMANENT; 566 if (pde->proc_ops->proc_read_iter) 567 pde->flags |= PROC_ENTRY_proc_read_iter; 568 #ifdef CONFIG_COMPAT 569 if (pde->proc_ops->proc_compat_ioctl) 570 pde->flags |= PROC_ENTRY_proc_compat_ioctl; 571 #endif 572 } 573 574 struct proc_dir_entry *proc_create_data(const char *name, umode_t mode, 575 struct proc_dir_entry *parent, 576 const struct proc_ops *proc_ops, void *data) 577 { 578 struct proc_dir_entry *p; 579 580 p = proc_create_reg(name, mode, &parent, data); 581 if (!p) 582 return NULL; 583 p->proc_ops = proc_ops; 584 pde_set_flags(p); 585 return proc_register(parent, p); 586 } 587 EXPORT_SYMBOL(proc_create_data); 588 589 struct proc_dir_entry *proc_create(const char *name, umode_t mode, 590 struct proc_dir_entry *parent, 591 const struct proc_ops *proc_ops) 592 { 593 return proc_create_data(name, mode, parent, proc_ops, NULL); 594 } 595 EXPORT_SYMBOL(proc_create); 596 597 static int proc_seq_open(struct inode *inode, struct file *file) 598 { 599 struct proc_dir_entry *de = PDE(inode); 600 601 if (de->state_size) 602 return seq_open_private(file, de->seq_ops, de->state_size); 603 return seq_open(file, de->seq_ops); 604 } 605 606 static int proc_seq_release(struct inode *inode, struct file *file) 607 { 608 struct proc_dir_entry *de = PDE(inode); 609 610 if (de->state_size) 611 return seq_release_private(inode, file); 612 return seq_release(inode, file); 613 } 614 615 static const struct proc_ops proc_seq_ops = { 616 /* not permanent -- can call into arbitrary seq_operations */ 617 .proc_open = proc_seq_open, 618 .proc_read_iter = seq_read_iter, 619 .proc_lseek = seq_lseek, 620 .proc_release = proc_seq_release, 621 }; 622 623 struct proc_dir_entry *proc_create_seq_private(const char *name, umode_t mode, 624 struct proc_dir_entry *parent, const struct seq_operations *ops, 625 unsigned int state_size, void *data) 626 { 627 struct proc_dir_entry *p; 628 629 p = proc_create_reg(name, mode, &parent, data); 630 if (!p) 631 return NULL; 632 p->proc_ops = &proc_seq_ops; 633 p->seq_ops = ops; 634 p->state_size = state_size; 635 pde_set_flags(p); 636 return proc_register(parent, p); 637 } 638 EXPORT_SYMBOL(proc_create_seq_private); 639 640 static int proc_single_open(struct inode *inode, struct file *file) 641 { 642 struct proc_dir_entry *de = PDE(inode); 643 644 return single_open(file, de->single_show, de->data); 645 } 646 647 static const struct proc_ops proc_single_ops = { 648 /* not permanent -- can call into arbitrary ->single_show */ 649 .proc_open = proc_single_open, 650 .proc_read_iter = seq_read_iter, 651 .proc_lseek = seq_lseek, 652 .proc_release = single_release, 653 }; 654 655 struct proc_dir_entry *proc_create_single_data(const char *name, umode_t mode, 656 struct proc_dir_entry *parent, 657 int (*show)(struct seq_file *, void *), void *data) 658 { 659 struct proc_dir_entry *p; 660 661 p = proc_create_reg(name, mode, &parent, data); 662 if (!p) 663 return NULL; 664 p->proc_ops = &proc_single_ops; 665 p->single_show = show; 666 pde_set_flags(p); 667 return proc_register(parent, p); 668 } 669 EXPORT_SYMBOL(proc_create_single_data); 670 671 void proc_set_size(struct proc_dir_entry *de, loff_t size) 672 { 673 de->size = size; 674 } 675 EXPORT_SYMBOL(proc_set_size); 676 677 void proc_set_user(struct proc_dir_entry *de, kuid_t uid, kgid_t gid) 678 { 679 de->uid = uid; 680 de->gid = gid; 681 } 682 EXPORT_SYMBOL(proc_set_user); 683 684 void pde_put(struct proc_dir_entry *pde) 685 { 686 if (refcount_dec_and_test(&pde->refcnt)) { 687 proc_free_inum(pde->low_ino); 688 pde_free(pde); 689 } 690 } 691 692 /* 693 * Remove a /proc entry and free it if it's not currently in use. 694 */ 695 void remove_proc_entry(const char *name, struct proc_dir_entry *parent) 696 { 697 struct proc_dir_entry *de = NULL; 698 const char *fn = name; 699 unsigned int len; 700 701 write_lock(&proc_subdir_lock); 702 if (__xlate_proc_name(name, &parent, &fn) != 0) { 703 write_unlock(&proc_subdir_lock); 704 return; 705 } 706 len = strlen(fn); 707 708 de = pde_subdir_find(parent, fn, len); 709 if (de) { 710 if (unlikely(pde_is_permanent(de))) { 711 WARN(1, "removing permanent /proc entry '%s'", de->name); 712 de = NULL; 713 } else { 714 rb_erase(&de->subdir_node, &parent->subdir); 715 if (S_ISDIR(de->mode)) 716 parent->nlink--; 717 } 718 } 719 write_unlock(&proc_subdir_lock); 720 if (!de) { 721 WARN(1, "name '%s'\n", name); 722 return; 723 } 724 725 proc_entry_rundown(de); 726 727 WARN(pde_subdir_first(de), 728 "%s: removing non-empty directory '%s/%s', leaking at least '%s'\n", 729 __func__, de->parent->name, de->name, pde_subdir_first(de)->name); 730 pde_put(de); 731 } 732 EXPORT_SYMBOL(remove_proc_entry); 733 734 int remove_proc_subtree(const char *name, struct proc_dir_entry *parent) 735 { 736 struct proc_dir_entry *root = NULL, *de, *next; 737 const char *fn = name; 738 unsigned int len; 739 740 write_lock(&proc_subdir_lock); 741 if (__xlate_proc_name(name, &parent, &fn) != 0) { 742 write_unlock(&proc_subdir_lock); 743 return -ENOENT; 744 } 745 len = strlen(fn); 746 747 root = pde_subdir_find(parent, fn, len); 748 if (!root) { 749 write_unlock(&proc_subdir_lock); 750 return -ENOENT; 751 } 752 if (unlikely(pde_is_permanent(root))) { 753 write_unlock(&proc_subdir_lock); 754 WARN(1, "removing permanent /proc entry '%s/%s'", 755 root->parent->name, root->name); 756 return -EINVAL; 757 } 758 rb_erase(&root->subdir_node, &parent->subdir); 759 760 de = root; 761 while (1) { 762 next = pde_subdir_first(de); 763 if (next) { 764 if (unlikely(pde_is_permanent(next))) { 765 write_unlock(&proc_subdir_lock); 766 WARN(1, "removing permanent /proc entry '%s/%s'", 767 next->parent->name, next->name); 768 return -EINVAL; 769 } 770 rb_erase(&next->subdir_node, &de->subdir); 771 de = next; 772 continue; 773 } 774 next = de->parent; 775 if (S_ISDIR(de->mode)) 776 next->nlink--; 777 write_unlock(&proc_subdir_lock); 778 779 proc_entry_rundown(de); 780 if (de == root) 781 break; 782 pde_put(de); 783 784 write_lock(&proc_subdir_lock); 785 de = next; 786 } 787 pde_put(root); 788 return 0; 789 } 790 EXPORT_SYMBOL(remove_proc_subtree); 791 792 void *proc_get_parent_data(const struct inode *inode) 793 { 794 struct proc_dir_entry *de = PDE(inode); 795 return de->parent->data; 796 } 797 EXPORT_SYMBOL_GPL(proc_get_parent_data); 798 799 void proc_remove(struct proc_dir_entry *de) 800 { 801 if (de) 802 remove_proc_subtree(de->name, de->parent); 803 } 804 EXPORT_SYMBOL(proc_remove); 805 806 /* 807 * Pull a user buffer into memory and pass it to the file's write handler if 808 * one is supplied. The ->write() method is permitted to modify the 809 * kernel-side buffer. 810 */ 811 ssize_t proc_simple_write(struct file *f, const char __user *ubuf, size_t size, 812 loff_t *_pos) 813 { 814 struct proc_dir_entry *pde = PDE(file_inode(f)); 815 char *buf; 816 int ret; 817 818 if (!pde->write) 819 return -EACCES; 820 if (size == 0 || size > PAGE_SIZE - 1) 821 return -EINVAL; 822 buf = memdup_user_nul(ubuf, size); 823 if (IS_ERR(buf)) 824 return PTR_ERR(buf); 825 ret = pde->write(f, buf, size); 826 kfree(buf); 827 return ret == 0 ? size : ret; 828 } 829