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_simple_get(&proc_inum_ida, 0, UINT_MAX - PROC_DYNAMIC_FIRST + 1, 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_simple_remove(&proc_inum_ida, inum - PROC_DYNAMIC_FIRST); 217 } 218 219 static int proc_misc_d_revalidate(struct dentry *dentry, unsigned int flags) 220 { 221 if (flags & LOOKUP_RCU) 222 return -ECHILD; 223 224 if (atomic_read(&PDE(d_inode(dentry))->in_use) < 0) 225 return 0; /* revalidate */ 226 return 1; 227 } 228 229 static int proc_misc_d_delete(const struct dentry *dentry) 230 { 231 return atomic_read(&PDE(d_inode(dentry))->in_use) < 0; 232 } 233 234 static const struct dentry_operations proc_misc_dentry_ops = { 235 .d_revalidate = proc_misc_d_revalidate, 236 .d_delete = proc_misc_d_delete, 237 }; 238 239 /* 240 * Don't create negative dentries here, return -ENOENT by hand 241 * instead. 242 */ 243 struct dentry *proc_lookup_de(struct inode *dir, struct dentry *dentry, 244 struct proc_dir_entry *de) 245 { 246 struct inode *inode; 247 248 read_lock(&proc_subdir_lock); 249 de = pde_subdir_find(de, dentry->d_name.name, dentry->d_name.len); 250 if (de) { 251 pde_get(de); 252 read_unlock(&proc_subdir_lock); 253 inode = proc_get_inode(dir->i_sb, de); 254 if (!inode) 255 return ERR_PTR(-ENOMEM); 256 d_set_d_op(dentry, de->proc_dops); 257 return d_splice_alias(inode, dentry); 258 } 259 read_unlock(&proc_subdir_lock); 260 return ERR_PTR(-ENOENT); 261 } 262 263 struct dentry *proc_lookup(struct inode *dir, struct dentry *dentry, 264 unsigned int flags) 265 { 266 struct proc_fs_info *fs_info = proc_sb_info(dir->i_sb); 267 268 if (fs_info->pidonly == PROC_PIDONLY_ON) 269 return ERR_PTR(-ENOENT); 270 271 return proc_lookup_de(dir, dentry, PDE(dir)); 272 } 273 274 /* 275 * This returns non-zero if at EOF, so that the /proc 276 * root directory can use this and check if it should 277 * continue with the <pid> entries.. 278 * 279 * Note that the VFS-layer doesn't care about the return 280 * value of the readdir() call, as long as it's non-negative 281 * for success.. 282 */ 283 int proc_readdir_de(struct file *file, struct dir_context *ctx, 284 struct proc_dir_entry *de) 285 { 286 int i; 287 288 if (!dir_emit_dots(file, ctx)) 289 return 0; 290 291 i = ctx->pos - 2; 292 read_lock(&proc_subdir_lock); 293 de = pde_subdir_first(de); 294 for (;;) { 295 if (!de) { 296 read_unlock(&proc_subdir_lock); 297 return 0; 298 } 299 if (!i) 300 break; 301 de = pde_subdir_next(de); 302 i--; 303 } 304 305 do { 306 struct proc_dir_entry *next; 307 pde_get(de); 308 read_unlock(&proc_subdir_lock); 309 if (!dir_emit(ctx, de->name, de->namelen, 310 de->low_ino, de->mode >> 12)) { 311 pde_put(de); 312 return 0; 313 } 314 ctx->pos++; 315 read_lock(&proc_subdir_lock); 316 next = pde_subdir_next(de); 317 pde_put(de); 318 de = next; 319 } while (de); 320 read_unlock(&proc_subdir_lock); 321 return 1; 322 } 323 324 int proc_readdir(struct file *file, struct dir_context *ctx) 325 { 326 struct inode *inode = file_inode(file); 327 struct proc_fs_info *fs_info = proc_sb_info(inode->i_sb); 328 329 if (fs_info->pidonly == PROC_PIDONLY_ON) 330 return 1; 331 332 return proc_readdir_de(file, ctx, PDE(inode)); 333 } 334 335 /* 336 * These are the generic /proc directory operations. They 337 * use the in-memory "struct proc_dir_entry" tree to parse 338 * the /proc directory. 339 */ 340 static const struct file_operations proc_dir_operations = { 341 .llseek = generic_file_llseek, 342 .read = generic_read_dir, 343 .iterate_shared = proc_readdir, 344 }; 345 346 static int proc_net_d_revalidate(struct dentry *dentry, unsigned int flags) 347 { 348 return 0; 349 } 350 351 const struct dentry_operations proc_net_dentry_ops = { 352 .d_revalidate = proc_net_d_revalidate, 353 .d_delete = always_delete_dentry, 354 }; 355 356 /* 357 * proc directories can do almost nothing.. 358 */ 359 static const struct inode_operations proc_dir_inode_operations = { 360 .lookup = proc_lookup, 361 .getattr = proc_getattr, 362 .setattr = proc_notify_change, 363 }; 364 365 /* returns the registered entry, or frees dp and returns NULL on failure */ 366 struct proc_dir_entry *proc_register(struct proc_dir_entry *dir, 367 struct proc_dir_entry *dp) 368 { 369 if (proc_alloc_inum(&dp->low_ino)) 370 goto out_free_entry; 371 372 write_lock(&proc_subdir_lock); 373 dp->parent = dir; 374 if (pde_subdir_insert(dir, dp) == false) { 375 WARN(1, "proc_dir_entry '%s/%s' already registered\n", 376 dir->name, dp->name); 377 write_unlock(&proc_subdir_lock); 378 goto out_free_inum; 379 } 380 dir->nlink++; 381 write_unlock(&proc_subdir_lock); 382 383 return dp; 384 out_free_inum: 385 proc_free_inum(dp->low_ino); 386 out_free_entry: 387 pde_free(dp); 388 return NULL; 389 } 390 391 static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent, 392 const char *name, 393 umode_t mode, 394 nlink_t nlink) 395 { 396 struct proc_dir_entry *ent = NULL; 397 const char *fn; 398 struct qstr qstr; 399 400 if (xlate_proc_name(name, parent, &fn) != 0) 401 goto out; 402 qstr.name = fn; 403 qstr.len = strlen(fn); 404 if (qstr.len == 0 || qstr.len >= 256) { 405 WARN(1, "name len %u\n", qstr.len); 406 return NULL; 407 } 408 if (qstr.len == 1 && fn[0] == '.') { 409 WARN(1, "name '.'\n"); 410 return NULL; 411 } 412 if (qstr.len == 2 && fn[0] == '.' && fn[1] == '.') { 413 WARN(1, "name '..'\n"); 414 return NULL; 415 } 416 if (*parent == &proc_root && name_to_int(&qstr) != ~0U) { 417 WARN(1, "create '/proc/%s' by hand\n", qstr.name); 418 return NULL; 419 } 420 if (is_empty_pde(*parent)) { 421 WARN(1, "attempt to add to permanently empty directory"); 422 return NULL; 423 } 424 425 ent = kmem_cache_zalloc(proc_dir_entry_cache, GFP_KERNEL); 426 if (!ent) 427 goto out; 428 429 if (qstr.len + 1 <= SIZEOF_PDE_INLINE_NAME) { 430 ent->name = ent->inline_name; 431 } else { 432 ent->name = kmalloc(qstr.len + 1, GFP_KERNEL); 433 if (!ent->name) { 434 pde_free(ent); 435 return NULL; 436 } 437 } 438 439 memcpy(ent->name, fn, qstr.len + 1); 440 ent->namelen = qstr.len; 441 ent->mode = mode; 442 ent->nlink = nlink; 443 ent->subdir = RB_ROOT; 444 refcount_set(&ent->refcnt, 1); 445 spin_lock_init(&ent->pde_unload_lock); 446 INIT_LIST_HEAD(&ent->pde_openers); 447 proc_set_user(ent, (*parent)->uid, (*parent)->gid); 448 449 ent->proc_dops = &proc_misc_dentry_ops; 450 /* Revalidate everything under /proc/${pid}/net */ 451 if ((*parent)->proc_dops == &proc_net_dentry_ops) 452 pde_force_lookup(ent); 453 454 out: 455 return ent; 456 } 457 458 struct proc_dir_entry *proc_symlink(const char *name, 459 struct proc_dir_entry *parent, const char *dest) 460 { 461 struct proc_dir_entry *ent; 462 463 ent = __proc_create(&parent, name, 464 (S_IFLNK | S_IRUGO | S_IWUGO | S_IXUGO),1); 465 466 if (ent) { 467 ent->data = kmalloc((ent->size=strlen(dest))+1, GFP_KERNEL); 468 if (ent->data) { 469 strcpy((char*)ent->data,dest); 470 ent->proc_iops = &proc_link_inode_operations; 471 ent = proc_register(parent, ent); 472 } else { 473 pde_free(ent); 474 ent = NULL; 475 } 476 } 477 return ent; 478 } 479 EXPORT_SYMBOL(proc_symlink); 480 481 struct proc_dir_entry *_proc_mkdir(const char *name, umode_t mode, 482 struct proc_dir_entry *parent, void *data, bool force_lookup) 483 { 484 struct proc_dir_entry *ent; 485 486 if (mode == 0) 487 mode = S_IRUGO | S_IXUGO; 488 489 ent = __proc_create(&parent, name, S_IFDIR | mode, 2); 490 if (ent) { 491 ent->data = data; 492 ent->proc_dir_ops = &proc_dir_operations; 493 ent->proc_iops = &proc_dir_inode_operations; 494 if (force_lookup) { 495 pde_force_lookup(ent); 496 } 497 ent = proc_register(parent, ent); 498 } 499 return ent; 500 } 501 EXPORT_SYMBOL_GPL(_proc_mkdir); 502 503 struct proc_dir_entry *proc_mkdir_data(const char *name, umode_t mode, 504 struct proc_dir_entry *parent, void *data) 505 { 506 return _proc_mkdir(name, mode, parent, data, false); 507 } 508 EXPORT_SYMBOL_GPL(proc_mkdir_data); 509 510 struct proc_dir_entry *proc_mkdir_mode(const char *name, umode_t mode, 511 struct proc_dir_entry *parent) 512 { 513 return proc_mkdir_data(name, mode, parent, NULL); 514 } 515 EXPORT_SYMBOL(proc_mkdir_mode); 516 517 struct proc_dir_entry *proc_mkdir(const char *name, 518 struct proc_dir_entry *parent) 519 { 520 return proc_mkdir_data(name, 0, parent, NULL); 521 } 522 EXPORT_SYMBOL(proc_mkdir); 523 524 struct proc_dir_entry *proc_create_mount_point(const char *name) 525 { 526 umode_t mode = S_IFDIR | S_IRUGO | S_IXUGO; 527 struct proc_dir_entry *ent, *parent = NULL; 528 529 ent = __proc_create(&parent, name, mode, 2); 530 if (ent) { 531 ent->data = NULL; 532 ent->proc_dir_ops = NULL; 533 ent->proc_iops = NULL; 534 ent = proc_register(parent, ent); 535 } 536 return ent; 537 } 538 EXPORT_SYMBOL(proc_create_mount_point); 539 540 struct proc_dir_entry *proc_create_reg(const char *name, umode_t mode, 541 struct proc_dir_entry **parent, void *data) 542 { 543 struct proc_dir_entry *p; 544 545 if ((mode & S_IFMT) == 0) 546 mode |= S_IFREG; 547 if ((mode & S_IALLUGO) == 0) 548 mode |= S_IRUGO; 549 if (WARN_ON_ONCE(!S_ISREG(mode))) 550 return NULL; 551 552 p = __proc_create(parent, name, mode, 1); 553 if (p) { 554 p->proc_iops = &proc_file_inode_operations; 555 p->data = data; 556 } 557 return p; 558 } 559 560 static void pde_set_flags(struct proc_dir_entry *pde) 561 { 562 if (pde->proc_ops->proc_flags & PROC_ENTRY_PERMANENT) 563 pde->flags |= PROC_ENTRY_PERMANENT; 564 if (pde->proc_ops->proc_read_iter) 565 pde->flags |= PROC_ENTRY_proc_read_iter; 566 #ifdef CONFIG_COMPAT 567 if (pde->proc_ops->proc_compat_ioctl) 568 pde->flags |= PROC_ENTRY_proc_compat_ioctl; 569 #endif 570 } 571 572 struct proc_dir_entry *proc_create_data(const char *name, umode_t mode, 573 struct proc_dir_entry *parent, 574 const struct proc_ops *proc_ops, void *data) 575 { 576 struct proc_dir_entry *p; 577 578 p = proc_create_reg(name, mode, &parent, data); 579 if (!p) 580 return NULL; 581 p->proc_ops = proc_ops; 582 pde_set_flags(p); 583 return proc_register(parent, p); 584 } 585 EXPORT_SYMBOL(proc_create_data); 586 587 struct proc_dir_entry *proc_create(const char *name, umode_t mode, 588 struct proc_dir_entry *parent, 589 const struct proc_ops *proc_ops) 590 { 591 return proc_create_data(name, mode, parent, proc_ops, NULL); 592 } 593 EXPORT_SYMBOL(proc_create); 594 595 static int proc_seq_open(struct inode *inode, struct file *file) 596 { 597 struct proc_dir_entry *de = PDE(inode); 598 599 if (de->state_size) 600 return seq_open_private(file, de->seq_ops, de->state_size); 601 return seq_open(file, de->seq_ops); 602 } 603 604 static int proc_seq_release(struct inode *inode, struct file *file) 605 { 606 struct proc_dir_entry *de = PDE(inode); 607 608 if (de->state_size) 609 return seq_release_private(inode, file); 610 return seq_release(inode, file); 611 } 612 613 static const struct proc_ops proc_seq_ops = { 614 /* not permanent -- can call into arbitrary seq_operations */ 615 .proc_open = proc_seq_open, 616 .proc_read_iter = seq_read_iter, 617 .proc_lseek = seq_lseek, 618 .proc_release = proc_seq_release, 619 }; 620 621 struct proc_dir_entry *proc_create_seq_private(const char *name, umode_t mode, 622 struct proc_dir_entry *parent, const struct seq_operations *ops, 623 unsigned int state_size, void *data) 624 { 625 struct proc_dir_entry *p; 626 627 p = proc_create_reg(name, mode, &parent, data); 628 if (!p) 629 return NULL; 630 p->proc_ops = &proc_seq_ops; 631 p->seq_ops = ops; 632 p->state_size = state_size; 633 pde_set_flags(p); 634 return proc_register(parent, p); 635 } 636 EXPORT_SYMBOL(proc_create_seq_private); 637 638 static int proc_single_open(struct inode *inode, struct file *file) 639 { 640 struct proc_dir_entry *de = PDE(inode); 641 642 return single_open(file, de->single_show, de->data); 643 } 644 645 static const struct proc_ops proc_single_ops = { 646 /* not permanent -- can call into arbitrary ->single_show */ 647 .proc_open = proc_single_open, 648 .proc_read_iter = seq_read_iter, 649 .proc_lseek = seq_lseek, 650 .proc_release = single_release, 651 }; 652 653 struct proc_dir_entry *proc_create_single_data(const char *name, umode_t mode, 654 struct proc_dir_entry *parent, 655 int (*show)(struct seq_file *, void *), void *data) 656 { 657 struct proc_dir_entry *p; 658 659 p = proc_create_reg(name, mode, &parent, data); 660 if (!p) 661 return NULL; 662 p->proc_ops = &proc_single_ops; 663 p->single_show = show; 664 pde_set_flags(p); 665 return proc_register(parent, p); 666 } 667 EXPORT_SYMBOL(proc_create_single_data); 668 669 void proc_set_size(struct proc_dir_entry *de, loff_t size) 670 { 671 de->size = size; 672 } 673 EXPORT_SYMBOL(proc_set_size); 674 675 void proc_set_user(struct proc_dir_entry *de, kuid_t uid, kgid_t gid) 676 { 677 de->uid = uid; 678 de->gid = gid; 679 } 680 EXPORT_SYMBOL(proc_set_user); 681 682 void pde_put(struct proc_dir_entry *pde) 683 { 684 if (refcount_dec_and_test(&pde->refcnt)) { 685 proc_free_inum(pde->low_ino); 686 pde_free(pde); 687 } 688 } 689 690 /* 691 * Remove a /proc entry and free it if it's not currently in use. 692 */ 693 void remove_proc_entry(const char *name, struct proc_dir_entry *parent) 694 { 695 struct proc_dir_entry *de = NULL; 696 const char *fn = name; 697 unsigned int len; 698 699 write_lock(&proc_subdir_lock); 700 if (__xlate_proc_name(name, &parent, &fn) != 0) { 701 write_unlock(&proc_subdir_lock); 702 return; 703 } 704 len = strlen(fn); 705 706 de = pde_subdir_find(parent, fn, len); 707 if (de) { 708 if (unlikely(pde_is_permanent(de))) { 709 WARN(1, "removing permanent /proc entry '%s'", de->name); 710 de = NULL; 711 } else { 712 rb_erase(&de->subdir_node, &parent->subdir); 713 if (S_ISDIR(de->mode)) 714 parent->nlink--; 715 } 716 } 717 write_unlock(&proc_subdir_lock); 718 if (!de) { 719 WARN(1, "name '%s'\n", name); 720 return; 721 } 722 723 proc_entry_rundown(de); 724 725 WARN(pde_subdir_first(de), 726 "%s: removing non-empty directory '%s/%s', leaking at least '%s'\n", 727 __func__, de->parent->name, de->name, pde_subdir_first(de)->name); 728 pde_put(de); 729 } 730 EXPORT_SYMBOL(remove_proc_entry); 731 732 int remove_proc_subtree(const char *name, struct proc_dir_entry *parent) 733 { 734 struct proc_dir_entry *root = NULL, *de, *next; 735 const char *fn = name; 736 unsigned int len; 737 738 write_lock(&proc_subdir_lock); 739 if (__xlate_proc_name(name, &parent, &fn) != 0) { 740 write_unlock(&proc_subdir_lock); 741 return -ENOENT; 742 } 743 len = strlen(fn); 744 745 root = pde_subdir_find(parent, fn, len); 746 if (!root) { 747 write_unlock(&proc_subdir_lock); 748 return -ENOENT; 749 } 750 if (unlikely(pde_is_permanent(root))) { 751 write_unlock(&proc_subdir_lock); 752 WARN(1, "removing permanent /proc entry '%s/%s'", 753 root->parent->name, root->name); 754 return -EINVAL; 755 } 756 rb_erase(&root->subdir_node, &parent->subdir); 757 758 de = root; 759 while (1) { 760 next = pde_subdir_first(de); 761 if (next) { 762 if (unlikely(pde_is_permanent(next))) { 763 write_unlock(&proc_subdir_lock); 764 WARN(1, "removing permanent /proc entry '%s/%s'", 765 next->parent->name, next->name); 766 return -EINVAL; 767 } 768 rb_erase(&next->subdir_node, &de->subdir); 769 de = next; 770 continue; 771 } 772 next = de->parent; 773 if (S_ISDIR(de->mode)) 774 next->nlink--; 775 write_unlock(&proc_subdir_lock); 776 777 proc_entry_rundown(de); 778 if (de == root) 779 break; 780 pde_put(de); 781 782 write_lock(&proc_subdir_lock); 783 de = next; 784 } 785 pde_put(root); 786 return 0; 787 } 788 EXPORT_SYMBOL(remove_proc_subtree); 789 790 void *proc_get_parent_data(const struct inode *inode) 791 { 792 struct proc_dir_entry *de = PDE(inode); 793 return de->parent->data; 794 } 795 EXPORT_SYMBOL_GPL(proc_get_parent_data); 796 797 void proc_remove(struct proc_dir_entry *de) 798 { 799 if (de) 800 remove_proc_subtree(de->name, de->parent); 801 } 802 EXPORT_SYMBOL(proc_remove); 803 804 /* 805 * Pull a user buffer into memory and pass it to the file's write handler if 806 * one is supplied. The ->write() method is permitted to modify the 807 * kernel-side buffer. 808 */ 809 ssize_t proc_simple_write(struct file *f, const char __user *ubuf, size_t size, 810 loff_t *_pos) 811 { 812 struct proc_dir_entry *pde = PDE(file_inode(f)); 813 char *buf; 814 int ret; 815 816 if (!pde->write) 817 return -EACCES; 818 if (size == 0 || size > PAGE_SIZE - 1) 819 return -EINVAL; 820 buf = memdup_user_nul(ubuf, size); 821 if (IS_ERR(buf)) 822 return PTR_ERR(buf); 823 ret = pde->write(f, buf, size); 824 kfree(buf); 825 return ret == 0 ? size : ret; 826 } 827