1 /* $NetBSD: tmpfs_subr.c,v 1.35 2007/07/09 21:10:50 ad Exp $ */ 2 3 /*- 4 * Copyright (c) 2005 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Julio M. Merino Vidal, developed as part of Google's Summer of Code 9 * 2005 program. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 23 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 30 * POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 /* 34 * Efficient memory file system supporting functions. 35 */ 36 37 #include <sys/kernel.h> 38 #include <sys/param.h> 39 #include <sys/namei.h> 40 #include <sys/priv.h> 41 #include <sys/proc.h> 42 #include <sys/stat.h> 43 #include <sys/systm.h> 44 #include <sys/vnode.h> 45 #include <sys/vmmeter.h> 46 47 #include <vm/vm.h> 48 #include <vm/vm_object.h> 49 #include <vm/vm_page.h> 50 #include <vm/vm_pager.h> 51 #include <vm/vm_extern.h> 52 53 #include <vfs/tmpfs/tmpfs.h> 54 #include <vfs/tmpfs/tmpfs_vnops.h> 55 56 static ino_t tmpfs_fetch_ino(struct tmpfs_mount *); 57 58 static int tmpfs_dirtree_compare(struct tmpfs_dirent *a, 59 struct tmpfs_dirent *b); 60 RB_GENERATE(tmpfs_dirtree, tmpfs_dirent, rb_node, tmpfs_dirtree_compare); 61 62 static int tmpfs_dirtree_compare_cookie(struct tmpfs_dirent *a, 63 struct tmpfs_dirent *b); 64 RB_GENERATE(tmpfs_dirtree_cookie, tmpfs_dirent, 65 rb_cookienode, tmpfs_dirtree_compare_cookie); 66 67 68 /* --------------------------------------------------------------------- */ 69 70 /* 71 * Allocates a new node of type 'type' inside the 'tmp' mount point, with 72 * its owner set to 'uid', its group to 'gid' and its mode set to 'mode', 73 * using the credentials of the process 'p'. 74 * 75 * If the node type is set to 'VDIR', then the parent parameter must point 76 * to the parent directory of the node being created. It may only be NULL 77 * while allocating the root node. 78 * 79 * If the node type is set to 'VBLK' or 'VCHR', then the rdev parameter 80 * specifies the device the node represents. 81 * 82 * If the node type is set to 'VLNK', then the parameter target specifies 83 * the file name of the target file for the symbolic link that is being 84 * created. 85 * 86 * Note that new nodes are retrieved from the available list if it has 87 * items or, if it is empty, from the node pool as long as there is enough 88 * space to create them. 89 * 90 * Returns zero on success or an appropriate error code on failure. 91 */ 92 int 93 tmpfs_alloc_node(struct tmpfs_mount *tmp, enum vtype type, 94 uid_t uid, gid_t gid, mode_t mode, 95 char *target, int rmajor, int rminor, 96 struct tmpfs_node **node) 97 { 98 struct tmpfs_node *nnode; 99 struct timespec ts; 100 udev_t rdev; 101 102 KKASSERT(IFF(type == VLNK, target != NULL)); 103 KKASSERT(IFF(type == VBLK || type == VCHR, rmajor != VNOVAL)); 104 105 if (tmp->tm_nodes_inuse >= tmp->tm_nodes_max) 106 return (ENOSPC); 107 108 nnode = objcache_get(tmp->tm_node_pool, M_WAITOK | M_NULLOK); 109 if (nnode == NULL) 110 return (ENOSPC); 111 112 /* Generic initialization. */ 113 nnode->tn_type = type; 114 vfs_timestamp(&ts); 115 nnode->tn_ctime = nnode->tn_mtime = nnode->tn_atime 116 = ts.tv_sec; 117 nnode->tn_ctimensec = nnode->tn_mtimensec = nnode->tn_atimensec 118 = ts.tv_nsec; 119 nnode->tn_uid = uid; 120 nnode->tn_gid = gid; 121 nnode->tn_mode = mode; 122 nnode->tn_id = tmpfs_fetch_ino(tmp); 123 nnode->tn_advlock.init_done = 0; 124 KKASSERT(nnode->tn_links == 0); 125 126 /* Type-specific initialization. */ 127 switch (nnode->tn_type) { 128 case VBLK: 129 case VCHR: 130 rdev = makeudev(rmajor, rminor); 131 if (rdev == NOUDEV) { 132 objcache_put(tmp->tm_node_pool, nnode); 133 return(EINVAL); 134 } 135 nnode->tn_rdev = rdev; 136 break; 137 138 case VDIR: 139 RB_INIT(&nnode->tn_dir.tn_dirtree); 140 RB_INIT(&nnode->tn_dir.tn_cookietree); 141 nnode->tn_size = 0; 142 break; 143 144 case VFIFO: 145 /* FALLTHROUGH */ 146 case VSOCK: 147 break; 148 149 case VLNK: 150 nnode->tn_size = strlen(target); 151 nnode->tn_link = kmalloc(nnode->tn_size + 1, tmp->tm_name_zone, 152 M_WAITOK | M_NULLOK); 153 if (nnode->tn_link == NULL) { 154 objcache_put(tmp->tm_node_pool, nnode); 155 return (ENOSPC); 156 } 157 bcopy(target, nnode->tn_link, nnode->tn_size); 158 nnode->tn_link[nnode->tn_size] = '\0'; 159 break; 160 161 case VREG: 162 nnode->tn_reg.tn_aobj = swap_pager_alloc(NULL, 0, 163 VM_PROT_DEFAULT, 0); 164 nnode->tn_reg.tn_aobj_pages = 0; 165 nnode->tn_size = 0; 166 vm_object_set_flag(nnode->tn_reg.tn_aobj, OBJ_NOPAGEIN); 167 break; 168 169 default: 170 panic("tmpfs_alloc_node: type %p %d", nnode, (int)nnode->tn_type); 171 } 172 173 TMPFS_NODE_LOCK(nnode); 174 TMPFS_LOCK(tmp); 175 LIST_INSERT_HEAD(&tmp->tm_nodes_used, nnode, tn_entries); 176 tmp->tm_nodes_inuse++; 177 TMPFS_UNLOCK(tmp); 178 TMPFS_NODE_UNLOCK(nnode); 179 180 *node = nnode; 181 return 0; 182 } 183 184 /* --------------------------------------------------------------------- */ 185 186 /* 187 * Destroys the node pointed to by node from the file system 'tmp'. 188 * If the node does not belong to the given mount point, the results are 189 * unpredicted. 190 * 191 * If the node references a directory; no entries are allowed because 192 * their removal could need a recursive algorithm, something forbidden in 193 * kernel space. Furthermore, there is not need to provide such 194 * functionality (recursive removal) because the only primitives offered 195 * to the user are the removal of empty directories and the deletion of 196 * individual files. 197 * 198 * Note that nodes are not really deleted; in fact, when a node has been 199 * allocated, it cannot be deleted during the whole life of the file 200 * system. Instead, they are moved to the available list and remain there 201 * until reused. 202 * 203 * A caller must have TMPFS_NODE_LOCK(node) and this function unlocks it. 204 */ 205 void 206 tmpfs_free_node(struct tmpfs_mount *tmp, struct tmpfs_node *node) 207 { 208 vm_pindex_t pages = 0; 209 210 #ifdef INVARIANTS 211 TMPFS_ASSERT_ELOCKED(node); 212 KKASSERT(node->tn_vnode == NULL); 213 KKASSERT((node->tn_vpstate & TMPFS_VNODE_ALLOCATING) == 0); 214 #endif 215 216 TMPFS_LOCK(tmp); 217 LIST_REMOVE(node, tn_entries); 218 tmp->tm_nodes_inuse--; 219 TMPFS_UNLOCK(tmp); 220 TMPFS_NODE_UNLOCK(node); /* Caller has this lock */ 221 222 switch (node->tn_type) { 223 case VNON: 224 /* Do not do anything. VNON is provided to let the 225 * allocation routine clean itself easily by avoiding 226 * duplicating code in it. */ 227 /* FALLTHROUGH */ 228 case VBLK: 229 /* FALLTHROUGH */ 230 case VCHR: 231 /* FALLTHROUGH */ 232 break; 233 case VDIR: 234 /* 235 * The parent link can be NULL if this is the root 236 * node or if it is a directory node that was rmdir'd. 237 * 238 * XXX what if node is a directory which still contains 239 * directory entries (e.g. due to a forced umount) ? 240 */ 241 node->tn_size = 0; 242 KKASSERT(node->tn_dir.tn_parent == NULL); 243 244 /* 245 * If the root node is being destroyed don't leave a 246 * dangling pointer in tmpfs_mount. 247 */ 248 if (node == tmp->tm_root) 249 tmp->tm_root = NULL; 250 break; 251 case VFIFO: 252 /* FALLTHROUGH */ 253 case VSOCK: 254 break; 255 256 case VLNK: 257 kfree(node->tn_link, tmp->tm_name_zone); 258 node->tn_link = NULL; 259 node->tn_size = 0; 260 break; 261 262 case VREG: 263 if (node->tn_reg.tn_aobj != NULL) 264 vm_object_deallocate(node->tn_reg.tn_aobj); 265 node->tn_reg.tn_aobj = NULL; 266 pages = node->tn_reg.tn_aobj_pages; 267 break; 268 269 default: 270 panic("tmpfs_free_node: type %p %d", node, (int)node->tn_type); 271 } 272 273 /* 274 * Clean up fields for the next allocation. The objcache only ctors 275 * new allocations. 276 */ 277 tmpfs_node_ctor(node, NULL, 0); 278 objcache_put(tmp->tm_node_pool, node); 279 /* node is now invalid */ 280 281 if (pages) 282 atomic_add_long(&tmp->tm_pages_used, -(long)pages); 283 } 284 285 /* --------------------------------------------------------------------- */ 286 287 /* 288 * Allocates a new directory entry for the node node with a name of name. 289 * The new directory entry is returned in *de. 290 * 291 * The link count of node is increased by one to reflect the new object 292 * referencing it. 293 * 294 * Returns zero on success or an appropriate error code on failure. 295 */ 296 int 297 tmpfs_alloc_dirent(struct tmpfs_mount *tmp, struct tmpfs_node *node, 298 const char *name, uint16_t len, struct tmpfs_dirent **de) 299 { 300 struct tmpfs_dirent *nde; 301 302 nde = objcache_get(tmp->tm_dirent_pool, M_WAITOK); 303 nde->td_name = kmalloc(len + 1, tmp->tm_name_zone, M_WAITOK | M_NULLOK); 304 if (nde->td_name == NULL) { 305 objcache_put(tmp->tm_dirent_pool, nde); 306 *de = NULL; 307 return (ENOSPC); 308 } 309 nde->td_namelen = len; 310 bcopy(name, nde->td_name, len); 311 nde->td_name[len] = '\0'; 312 313 nde->td_node = node; 314 315 TMPFS_NODE_LOCK(node); 316 ++node->tn_links; 317 TMPFS_NODE_UNLOCK(node); 318 319 *de = nde; 320 321 return 0; 322 } 323 324 /* --------------------------------------------------------------------- */ 325 326 /* 327 * Frees a directory entry. It is the caller's responsibility to destroy 328 * the node referenced by it if needed. 329 * 330 * The link count of node is decreased by one to reflect the removal of an 331 * object that referenced it. This only happens if 'node_exists' is true; 332 * otherwise the function will not access the node referred to by the 333 * directory entry, as it may already have been released from the outside. 334 */ 335 void 336 tmpfs_free_dirent(struct tmpfs_mount *tmp, struct tmpfs_dirent *de) 337 { 338 struct tmpfs_node *node; 339 340 node = de->td_node; 341 342 TMPFS_NODE_LOCK(node); 343 TMPFS_ASSERT_ELOCKED(node); 344 KKASSERT(node->tn_links > 0); 345 node->tn_links--; 346 TMPFS_NODE_UNLOCK(node); 347 348 kfree(de->td_name, tmp->tm_name_zone); 349 de->td_namelen = 0; 350 de->td_name = NULL; 351 de->td_node = NULL; 352 objcache_put(tmp->tm_dirent_pool, de); 353 } 354 355 /* --------------------------------------------------------------------- */ 356 357 /* 358 * Allocates a new vnode for the node node or returns a new reference to 359 * an existing one if the node had already a vnode referencing it. The 360 * resulting locked vnode is returned in *vpp. 361 * 362 * Returns zero on success or an appropriate error code on failure. 363 * 364 * The caller must ensure that node cannot go away (usually by holding 365 * the related directory entry). 366 * 367 * If dnode is non-NULL this routine avoids deadlocking against it but 368 * can return EAGAIN. Caller must try again. The dnode lock will cycle 369 * in this case, it remains locked on return in all cases. dnode must 370 * be shared-locked. 371 */ 372 int 373 tmpfs_alloc_vp(struct mount *mp, 374 struct tmpfs_node *dnode, struct tmpfs_node *node, int lkflag, 375 struct vnode **vpp) 376 { 377 int error = 0; 378 struct vnode *vp; 379 380 loop: 381 /* 382 * Interlocked extraction from node. This can race many things. 383 * We have to get a soft reference on the vnode while we hold 384 * the node locked, then acquire it properly and check for races. 385 */ 386 TMPFS_NODE_LOCK(node); 387 if ((vp = node->tn_vnode) != NULL) { 388 KKASSERT((node->tn_vpstate & TMPFS_VNODE_DOOMED) == 0); 389 vhold(vp); 390 TMPFS_NODE_UNLOCK(node); 391 392 if (dnode) { 393 /* 394 * Special-case handling to avoid deadlocking against 395 * dnode. 396 */ 397 if (vget(vp, (lkflag & ~LK_RETRY) | 398 LK_NOWAIT | 399 LK_EXCLUSIVE) != 0) { 400 TMPFS_NODE_UNLOCK(dnode); 401 if (vget(vp, (lkflag & ~LK_RETRY) | 402 LK_SLEEPFAIL | 403 LK_EXCLUSIVE) == 0) { 404 vn_unlock(vp); 405 } 406 vdrop(vp); 407 TMPFS_NODE_LOCK_SH(dnode); 408 kprintf("tmpfs: deadlock avoided\n"); 409 return EAGAIN; 410 } 411 } else { 412 /* 413 * Normal path 414 */ 415 if (vget(vp, lkflag | LK_EXCLUSIVE) != 0) { 416 vdrop(vp); 417 goto loop; 418 } 419 } 420 if (node->tn_vnode != vp) { 421 vput(vp); 422 vdrop(vp); 423 goto loop; 424 } 425 vdrop(vp); 426 goto out; 427 } 428 /* vp is NULL */ 429 430 /* 431 * This should never happen. 432 */ 433 if (node->tn_vpstate & TMPFS_VNODE_DOOMED) { 434 TMPFS_NODE_UNLOCK(node); 435 error = ENOENT; 436 goto out; 437 } 438 439 /* 440 * Interlock against other calls to tmpfs_alloc_vp() trying to 441 * allocate and assign a vp to node. 442 */ 443 if (node->tn_vpstate & TMPFS_VNODE_ALLOCATING) { 444 node->tn_vpstate |= TMPFS_VNODE_WANT; 445 error = tsleep(&node->tn_vpstate, PINTERLOCKED | PCATCH, 446 "tmpfs_alloc_vp", 0); 447 TMPFS_NODE_UNLOCK(node); 448 if (error) 449 return error; 450 goto loop; 451 } 452 node->tn_vpstate |= TMPFS_VNODE_ALLOCATING; 453 TMPFS_NODE_UNLOCK(node); 454 455 /* 456 * Allocate a new vnode (may block). The ALLOCATING flag should 457 * prevent a race against someone else assigning node->tn_vnode. 458 */ 459 error = getnewvnode(VT_TMPFS, mp, &vp, VLKTIMEOUT, LK_CANRECURSE); 460 if (error != 0) 461 goto unlock; 462 463 KKASSERT(node->tn_vnode == NULL); 464 KKASSERT(vp != NULL); 465 vp->v_data = node; 466 vp->v_type = node->tn_type; 467 468 /* Type-specific initialization. */ 469 switch (node->tn_type) { 470 case VBLK: 471 /* FALLTHROUGH */ 472 case VCHR: 473 /* FALLTHROUGH */ 474 case VSOCK: 475 break; 476 case VREG: 477 /* 478 * VMIO is mandatory. Tmpfs also supports KVABIO 479 * for its tmpfs_strategy(). 480 */ 481 vsetflags(vp, VKVABIO); 482 vinitvmio(vp, node->tn_size, TMPFS_BLKSIZE, -1); 483 break; 484 case VLNK: 485 break; 486 case VFIFO: 487 vp->v_ops = &mp->mnt_vn_fifo_ops; 488 break; 489 case VDIR: 490 break; 491 492 default: 493 panic("tmpfs_alloc_vp: type %p %d", node, (int)node->tn_type); 494 } 495 496 497 unlock: 498 TMPFS_NODE_LOCK(node); 499 500 KKASSERT(node->tn_vpstate & TMPFS_VNODE_ALLOCATING); 501 node->tn_vpstate &= ~TMPFS_VNODE_ALLOCATING; 502 node->tn_vnode = vp; 503 504 if (node->tn_vpstate & TMPFS_VNODE_WANT) { 505 node->tn_vpstate &= ~TMPFS_VNODE_WANT; 506 TMPFS_NODE_UNLOCK(node); 507 wakeup(&node->tn_vpstate); 508 } else { 509 TMPFS_NODE_UNLOCK(node); 510 } 511 512 out: 513 *vpp = vp; 514 KKASSERT(IFF(error == 0, *vpp != NULL && vn_islocked(*vpp))); 515 516 return error; 517 } 518 519 /* --------------------------------------------------------------------- */ 520 521 /* 522 * Destroys the association between the vnode vp and the node it 523 * references. 524 */ 525 void 526 tmpfs_free_vp(struct vnode *vp) 527 { 528 struct tmpfs_node *node; 529 530 node = VP_TO_TMPFS_NODE(vp); 531 532 TMPFS_NODE_LOCK(node); 533 KKASSERT(lockinuse(TMPFS_NODE_MTX(node))); 534 node->tn_vnode = NULL; 535 vp->v_data = NULL; 536 TMPFS_NODE_UNLOCK(node); 537 } 538 539 /* --------------------------------------------------------------------- */ 540 541 /* 542 * Allocates a new file of type 'type' and adds it to the parent directory 543 * 'dvp'; this addition is done using the component name given in 'cnp'. 544 * The ownership of the new file is automatically assigned based on the 545 * credentials of the caller (through 'cnp'), the group is set based on 546 * the parent directory and the mode is determined from the 'vap' argument. 547 * If successful, *vpp holds a vnode to the newly created file and zero 548 * is returned. Otherwise *vpp is NULL and the function returns an 549 * appropriate error code. 550 */ 551 int 552 tmpfs_alloc_file(struct vnode *dvp, struct vnode **vpp, struct vattr *vap, 553 struct namecache *ncp, struct ucred *cred, char *target) 554 { 555 int error; 556 struct tmpfs_dirent *de; 557 struct tmpfs_mount *tmp; 558 struct tmpfs_node *dnode; 559 struct tmpfs_node *node; 560 561 tmp = VFS_TO_TMPFS(dvp->v_mount); 562 dnode = VP_TO_TMPFS_DIR(dvp); 563 *vpp = NULL; 564 565 /* 566 * If the directory was removed but a process was CD'd into it, 567 * we do not allow any more file/dir creation within it. Otherwise 568 * we will lose track of it. 569 */ 570 KKASSERT(dnode->tn_type == VDIR); 571 if (dnode != tmp->tm_root && dnode->tn_dir.tn_parent == NULL) 572 return ENOENT; 573 574 /* 575 * Make sure the link count does not overflow. 576 */ 577 if (vap->va_type == VDIR && dnode->tn_links >= LINK_MAX) 578 return EMLINK; 579 580 /* Allocate a node that represents the new file. */ 581 error = tmpfs_alloc_node(tmp, vap->va_type, cred->cr_uid, 582 dnode->tn_gid, vap->va_mode, target, 583 vap->va_rmajor, vap->va_rminor, &node); 584 if (error != 0) 585 return error; 586 TMPFS_NODE_LOCK(node); 587 588 /* Allocate a directory entry that points to the new file. */ 589 error = tmpfs_alloc_dirent(tmp, node, ncp->nc_name, ncp->nc_nlen, &de); 590 if (error != 0) { 591 tmpfs_free_node(tmp, node); 592 /* eats node lock */ 593 return error; 594 } 595 596 /* Allocate a vnode for the new file. */ 597 error = tmpfs_alloc_vp(dvp->v_mount, NULL, node, LK_EXCLUSIVE, vpp); 598 if (error != 0) { 599 tmpfs_free_dirent(tmp, de); 600 tmpfs_free_node(tmp, node); 601 /* eats node lock */ 602 return error; 603 } 604 605 /* 606 * Now that all required items are allocated, we can proceed to 607 * insert the new node into the directory, an operation that 608 * cannot fail. 609 */ 610 tmpfs_dir_attach(dnode, de); 611 TMPFS_NODE_UNLOCK(node); 612 613 return error; 614 } 615 616 /* --------------------------------------------------------------------- */ 617 618 /* 619 * Attaches the directory entry de to the directory represented by dnode. 620 * Note that this does not change the link count of the node pointed by 621 * the directory entry, as this is done by tmpfs_alloc_dirent. 622 */ 623 void 624 tmpfs_dir_attach(struct tmpfs_node *dnode, struct tmpfs_dirent *de) 625 { 626 struct tmpfs_node *node = de->td_node; 627 628 TMPFS_NODE_LOCK(dnode); 629 if (node && node->tn_type == VDIR) { 630 TMPFS_NODE_LOCK(node); 631 ++node->tn_links; 632 node->tn_status |= TMPFS_NODE_CHANGED; 633 node->tn_dir.tn_parent = dnode; 634 ++dnode->tn_links; 635 TMPFS_NODE_UNLOCK(node); 636 } 637 RB_INSERT(tmpfs_dirtree, &dnode->tn_dir.tn_dirtree, de); 638 RB_INSERT(tmpfs_dirtree_cookie, &dnode->tn_dir.tn_cookietree, de); 639 dnode->tn_size += sizeof(struct tmpfs_dirent); 640 dnode->tn_status |= TMPFS_NODE_ACCESSED | TMPFS_NODE_CHANGED | 641 TMPFS_NODE_MODIFIED; 642 TMPFS_NODE_UNLOCK(dnode); 643 } 644 645 /* --------------------------------------------------------------------- */ 646 647 /* 648 * Detaches the directory entry de from the directory represented by dnode. 649 * Note that this does not change the link count of the node pointed by 650 * the directory entry, as this is done by tmpfs_free_dirent. 651 */ 652 void 653 tmpfs_dir_detach(struct tmpfs_node *dnode, struct tmpfs_dirent *de) 654 { 655 struct tmpfs_node *node = de->td_node; 656 657 TMPFS_NODE_LOCK(dnode); 658 RB_REMOVE(tmpfs_dirtree, &dnode->tn_dir.tn_dirtree, de); 659 RB_REMOVE(tmpfs_dirtree_cookie, &dnode->tn_dir.tn_cookietree, de); 660 dnode->tn_size -= sizeof(struct tmpfs_dirent); 661 dnode->tn_status |= TMPFS_NODE_ACCESSED | TMPFS_NODE_CHANGED | 662 TMPFS_NODE_MODIFIED; 663 TMPFS_NODE_UNLOCK(dnode); 664 665 /* 666 * Clean out the tn_parent pointer immediately when removing a 667 * directory. 668 * 669 * Removal of the parent linkage also cleans out the extra tn_links 670 * count we had on both node and dnode. 671 * 672 * node can be NULL (typ during a forced umount), in which case 673 * the mount code is dealing with the linkages from a linked list 674 * scan. 675 */ 676 if (node && node->tn_type == VDIR && node->tn_dir.tn_parent) { 677 TMPFS_NODE_LOCK(dnode); 678 TMPFS_NODE_LOCK(node); 679 KKASSERT(node->tn_dir.tn_parent == dnode); 680 dnode->tn_links--; 681 node->tn_links--; 682 node->tn_dir.tn_parent = NULL; 683 TMPFS_NODE_UNLOCK(node); 684 TMPFS_NODE_UNLOCK(dnode); 685 } 686 } 687 688 /* --------------------------------------------------------------------- */ 689 690 /* 691 * Looks for a directory entry in the directory represented by node. 692 * 'ncp' describes the name of the entry to look for. Note that the . 693 * and .. components are not allowed as they do not physically exist 694 * within directories. 695 * 696 * Returns a pointer to the entry when found, otherwise NULL. 697 * 698 * Caller must hold the node locked (shared ok) 699 */ 700 struct tmpfs_dirent * 701 tmpfs_dir_lookup(struct tmpfs_node *node, struct tmpfs_node *f, 702 struct namecache *ncp) 703 { 704 struct tmpfs_dirent *de; 705 int len = ncp->nc_nlen; 706 struct tmpfs_dirent wanted; 707 708 wanted.td_namelen = len; 709 wanted.td_name = ncp->nc_name; 710 711 TMPFS_VALIDATE_DIR(node); 712 713 de = RB_FIND(tmpfs_dirtree, &node->tn_dir.tn_dirtree, &wanted); 714 715 KKASSERT(f == NULL || f == de->td_node); 716 717 return de; 718 } 719 720 /* --------------------------------------------------------------------- */ 721 722 /* 723 * Helper function for tmpfs_readdir. Creates a '.' entry for the given 724 * directory and returns it in the uio space. The function returns 0 725 * on success, -1 if there was not enough space in the uio structure to 726 * hold the directory entry or an appropriate error code if another 727 * error happens. 728 */ 729 int 730 tmpfs_dir_getdotdent(struct tmpfs_node *node, struct uio *uio) 731 { 732 int error; 733 734 TMPFS_VALIDATE_DIR(node); 735 KKASSERT(uio->uio_offset == TMPFS_DIRCOOKIE_DOT); 736 737 if (vop_write_dirent(&error, uio, node->tn_id, DT_DIR, 1, ".")) 738 return -1; 739 if (error == 0) 740 uio->uio_offset = TMPFS_DIRCOOKIE_DOTDOT; 741 return error; 742 } 743 744 /* --------------------------------------------------------------------- */ 745 746 /* 747 * Helper function for tmpfs_readdir. Creates a '..' entry for the given 748 * directory and returns it in the uio space. The function returns 0 749 * on success, -1 if there was not enough space in the uio structure to 750 * hold the directory entry or an appropriate error code if another 751 * error happens. 752 */ 753 int 754 tmpfs_dir_getdotdotdent(struct tmpfs_mount *tmp, struct tmpfs_node *node, 755 struct uio *uio) 756 { 757 int error; 758 ino_t d_ino; 759 760 TMPFS_VALIDATE_DIR(node); 761 KKASSERT(uio->uio_offset == TMPFS_DIRCOOKIE_DOTDOT); 762 763 if (node->tn_dir.tn_parent) { 764 TMPFS_NODE_LOCK(node); 765 if (node->tn_dir.tn_parent) 766 d_ino = node->tn_dir.tn_parent->tn_id; 767 else 768 d_ino = tmp->tm_root->tn_id; 769 TMPFS_NODE_UNLOCK(node); 770 } else { 771 d_ino = tmp->tm_root->tn_id; 772 } 773 774 if (vop_write_dirent(&error, uio, d_ino, DT_DIR, 2, "..")) 775 return -1; 776 if (error == 0) { 777 struct tmpfs_dirent *de; 778 de = RB_MIN(tmpfs_dirtree_cookie, &node->tn_dir.tn_cookietree); 779 if (de == NULL) 780 uio->uio_offset = TMPFS_DIRCOOKIE_EOF; 781 else 782 uio->uio_offset = tmpfs_dircookie(de); 783 } 784 return error; 785 } 786 787 /* --------------------------------------------------------------------- */ 788 789 /* 790 * Lookup a directory entry by its associated cookie. 791 * 792 * Must be called with the directory node locked (shared ok) 793 */ 794 struct lubycookie_info { 795 off_t cookie; 796 struct tmpfs_dirent *de; 797 }; 798 799 static int 800 lubycookie_cmp(struct tmpfs_dirent *de, void *arg) 801 { 802 struct lubycookie_info *info = arg; 803 off_t cookie = tmpfs_dircookie(de); 804 805 if (cookie < info->cookie) 806 return(-1); 807 if (cookie > info->cookie) 808 return(1); 809 return(0); 810 } 811 812 static int 813 lubycookie_callback(struct tmpfs_dirent *de, void *arg) 814 { 815 struct lubycookie_info *info = arg; 816 817 if (tmpfs_dircookie(de) == info->cookie) { 818 info->de = de; 819 return(-1); 820 } 821 return(0); 822 } 823 824 struct tmpfs_dirent * 825 tmpfs_dir_lookupbycookie(struct tmpfs_node *node, off_t cookie) 826 { 827 struct lubycookie_info info; 828 829 info.cookie = cookie; 830 info.de = NULL; 831 RB_SCAN(tmpfs_dirtree_cookie, &node->tn_dir.tn_cookietree, 832 lubycookie_cmp, lubycookie_callback, &info); 833 return (info.de); 834 } 835 836 /* --------------------------------------------------------------------- */ 837 838 /* 839 * Helper function for tmpfs_readdir. Returns as much directory entries 840 * as can fit in the uio space. The read starts at uio->uio_offset. 841 * The function returns 0 on success, -1 if there was not enough space 842 * in the uio structure to hold the directory entry or an appropriate 843 * error code if another error happens. 844 * 845 * Caller must hold the node locked (shared ok) 846 */ 847 int 848 tmpfs_dir_getdents(struct tmpfs_node *node, struct uio *uio, off_t *cntp) 849 { 850 int error; 851 off_t startcookie; 852 struct tmpfs_dirent *de; 853 854 TMPFS_VALIDATE_DIR(node); 855 856 /* 857 * Locate the first directory entry we have to return. We have cached 858 * the last readdir in the node, so use those values if appropriate. 859 * Otherwise do a linear scan to find the requested entry. 860 */ 861 startcookie = uio->uio_offset; 862 KKASSERT(startcookie != TMPFS_DIRCOOKIE_DOT); 863 KKASSERT(startcookie != TMPFS_DIRCOOKIE_DOTDOT); 864 865 if (startcookie == TMPFS_DIRCOOKIE_EOF) 866 return 0; 867 868 de = tmpfs_dir_lookupbycookie(node, startcookie); 869 if (de == NULL) 870 return EINVAL; 871 872 /* 873 * Read as much entries as possible; i.e., until we reach the end of 874 * the directory or we exhaust uio space. 875 */ 876 do { 877 ino_t d_ino; 878 uint8_t d_type; 879 880 /* Create a dirent structure representing the current 881 * tmpfs_node and fill it. */ 882 d_ino = de->td_node->tn_id; 883 switch (de->td_node->tn_type) { 884 case VBLK: 885 d_type = DT_BLK; 886 break; 887 888 case VCHR: 889 d_type = DT_CHR; 890 break; 891 892 case VDIR: 893 d_type = DT_DIR; 894 break; 895 896 case VFIFO: 897 d_type = DT_FIFO; 898 break; 899 900 case VLNK: 901 d_type = DT_LNK; 902 break; 903 904 case VREG: 905 d_type = DT_REG; 906 break; 907 908 case VSOCK: 909 d_type = DT_SOCK; 910 break; 911 912 default: 913 panic("tmpfs_dir_getdents: type %p %d", 914 de->td_node, (int)de->td_node->tn_type); 915 } 916 KKASSERT(de->td_namelen < 256); /* 255 + 1 */ 917 918 if (vop_write_dirent(&error, uio, d_ino, d_type, 919 de->td_namelen, de->td_name)) { 920 error = -1; 921 break; 922 } 923 924 (*cntp)++; 925 de = RB_NEXT(tmpfs_dirtree_cookie, 926 node->tn_dir.tn_cookietree, de); 927 } while (error == 0 && uio->uio_resid > 0 && de != NULL); 928 929 /* Update the offset and cache. */ 930 if (de == NULL) { 931 uio->uio_offset = TMPFS_DIRCOOKIE_EOF; 932 } else { 933 uio->uio_offset = tmpfs_dircookie(de); 934 } 935 936 return error; 937 } 938 939 /* --------------------------------------------------------------------- */ 940 941 /* 942 * Resizes the aobj associated to the regular file pointed to by vp to 943 * the size newsize. 'vp' must point to a vnode that represents a regular 944 * file. 'newsize' must be positive. 945 * 946 * pass trivial as 1 when buf content will be overwritten, otherwise set 0 947 * to be zero filled. 948 * 949 * Returns zero on success or an appropriate error code on failure. 950 * 951 * Caller must hold the node exclusively locked. 952 */ 953 int 954 tmpfs_reg_resize(struct vnode *vp, off_t newsize, int trivial) 955 { 956 int error; 957 vm_pindex_t newpages, oldpages; 958 struct tmpfs_mount *tmp; 959 struct tmpfs_node *node; 960 off_t oldsize; 961 962 #ifdef INVARIANTS 963 KKASSERT(vp->v_type == VREG); 964 KKASSERT(newsize >= 0); 965 #endif 966 967 node = VP_TO_TMPFS_NODE(vp); 968 tmp = VFS_TO_TMPFS(vp->v_mount); 969 970 /* 971 * Convert the old and new sizes to the number of pages needed to 972 * store them. It may happen that we do not need to do anything 973 * because the last allocated page can accommodate the change on 974 * its own. 975 */ 976 oldsize = node->tn_size; 977 oldpages = round_page64(oldsize) / PAGE_SIZE; 978 KKASSERT(oldpages == node->tn_reg.tn_aobj_pages); 979 newpages = round_page64(newsize) / PAGE_SIZE; 980 981 if (newpages > oldpages && 982 tmp->tm_pages_used + newpages - oldpages > tmp->tm_pages_max) { 983 error = ENOSPC; 984 goto out; 985 } 986 node->tn_reg.tn_aobj_pages = newpages; 987 node->tn_size = newsize; 988 989 if (newpages != oldpages) 990 atomic_add_long(&tmp->tm_pages_used, (newpages - oldpages)); 991 992 /* 993 * When adjusting the vnode filesize and its VM object we must 994 * also adjust our backing VM object (aobj). The blocksize 995 * used must match the block sized we use for the buffer cache. 996 * 997 * The backing VM object may contain VM pages as well as swap 998 * assignments if we previously renamed main object pages into 999 * it during deactivation. 1000 */ 1001 if (newsize < oldsize) { 1002 vm_pindex_t osize; 1003 vm_pindex_t nsize; 1004 vm_object_t aobj; 1005 1006 error = nvtruncbuf(vp, newsize, TMPFS_BLKSIZE, -1, 0); 1007 aobj = node->tn_reg.tn_aobj; 1008 if (aobj) { 1009 osize = aobj->size; 1010 nsize = vp->v_object->size; 1011 if (nsize < osize) { 1012 aobj->size = osize; 1013 swap_pager_freespace(aobj, nsize, 1014 osize - nsize); 1015 vm_object_page_remove(aobj, nsize, osize, 1016 FALSE); 1017 } 1018 } 1019 } else { 1020 vm_object_t aobj; 1021 1022 error = nvextendbuf(vp, oldsize, newsize, 1023 TMPFS_BLKSIZE, TMPFS_BLKSIZE, 1024 -1, -1, trivial); 1025 aobj = node->tn_reg.tn_aobj; 1026 if (aobj) 1027 aobj->size = vp->v_object->size; 1028 } 1029 1030 out: 1031 return error; 1032 } 1033 1034 /* --------------------------------------------------------------------- */ 1035 1036 /* 1037 * Change flags of the given vnode. 1038 * Caller should execute tmpfs_update on vp after a successful execution. 1039 * The vnode must be locked on entry and remain locked on exit. 1040 */ 1041 int 1042 tmpfs_chflags(struct vnode *vp, int vaflags, struct ucred *cred) 1043 { 1044 int error; 1045 struct tmpfs_node *node; 1046 int flags; 1047 1048 KKASSERT(vn_islocked(vp)); 1049 1050 node = VP_TO_TMPFS_NODE(vp); 1051 flags = node->tn_flags; 1052 1053 /* Disallow this operation if the file system is mounted read-only. */ 1054 if (vp->v_mount->mnt_flag & MNT_RDONLY) 1055 return EROFS; 1056 error = vop_helper_setattr_flags(&flags, vaflags, node->tn_uid, cred); 1057 1058 /* Actually change the flags on the node itself */ 1059 if (error == 0) { 1060 TMPFS_NODE_LOCK(node); 1061 node->tn_flags = flags; 1062 node->tn_status |= TMPFS_NODE_CHANGED; 1063 TMPFS_NODE_UNLOCK(node); 1064 } 1065 1066 KKASSERT(vn_islocked(vp)); 1067 1068 return error; 1069 } 1070 1071 /* --------------------------------------------------------------------- */ 1072 1073 /* 1074 * Change access mode on the given vnode. 1075 * Caller should execute tmpfs_update on vp after a successful execution. 1076 * The vnode must be locked on entry and remain locked on exit. 1077 */ 1078 int 1079 tmpfs_chmod(struct vnode *vp, mode_t vamode, struct ucred *cred) 1080 { 1081 struct tmpfs_node *node; 1082 mode_t cur_mode; 1083 int error; 1084 1085 KKASSERT(vn_islocked(vp)); 1086 1087 node = VP_TO_TMPFS_NODE(vp); 1088 1089 /* Disallow this operation if the file system is mounted read-only. */ 1090 if (vp->v_mount->mnt_flag & MNT_RDONLY) 1091 return EROFS; 1092 1093 /* Immutable or append-only files cannot be modified, either. */ 1094 if (node->tn_flags & (IMMUTABLE | APPEND)) 1095 return EPERM; 1096 1097 cur_mode = node->tn_mode; 1098 error = vop_helper_chmod(vp, vamode, cred, node->tn_uid, node->tn_gid, 1099 &cur_mode); 1100 1101 if (error == 0 && 1102 (node->tn_mode & ALLPERMS) != (cur_mode & ALLPERMS)) { 1103 TMPFS_NODE_LOCK(node); 1104 node->tn_mode &= ~ALLPERMS; 1105 node->tn_mode |= cur_mode & ALLPERMS; 1106 1107 node->tn_status |= TMPFS_NODE_CHANGED; 1108 TMPFS_NODE_UNLOCK(node); 1109 } 1110 1111 KKASSERT(vn_islocked(vp)); 1112 1113 return 0; 1114 } 1115 1116 /* --------------------------------------------------------------------- */ 1117 1118 /* 1119 * Change ownership of the given vnode. At least one of uid or gid must 1120 * be different than VNOVAL. If one is set to that value, the attribute 1121 * is unchanged. 1122 * Caller should execute tmpfs_update on vp after a successful execution. 1123 * The vnode must be locked on entry and remain locked on exit. 1124 */ 1125 int 1126 tmpfs_chown(struct vnode *vp, uid_t uid, gid_t gid, struct ucred *cred) 1127 { 1128 mode_t cur_mode; 1129 uid_t cur_uid; 1130 gid_t cur_gid; 1131 struct tmpfs_node *node; 1132 int error; 1133 1134 KKASSERT(vn_islocked(vp)); 1135 node = VP_TO_TMPFS_NODE(vp); 1136 1137 /* Disallow this operation if the file system is mounted read-only. */ 1138 if (vp->v_mount->mnt_flag & MNT_RDONLY) 1139 return EROFS; 1140 1141 /* Immutable or append-only files cannot be modified, either. */ 1142 if (node->tn_flags & (IMMUTABLE | APPEND)) 1143 return EPERM; 1144 1145 cur_uid = node->tn_uid; 1146 cur_gid = node->tn_gid; 1147 cur_mode = node->tn_mode; 1148 error = vop_helper_chown(vp, uid, gid, cred, 1149 &cur_uid, &cur_gid, &cur_mode); 1150 1151 if (error == 0) { 1152 TMPFS_NODE_LOCK(node); 1153 if (cur_uid != node->tn_uid || 1154 cur_gid != node->tn_gid || 1155 cur_mode != node->tn_mode) { 1156 node->tn_uid = cur_uid; 1157 node->tn_gid = cur_gid; 1158 node->tn_mode = cur_mode; 1159 node->tn_status |= TMPFS_NODE_CHANGED; 1160 } 1161 TMPFS_NODE_UNLOCK(node); 1162 } 1163 1164 return error; 1165 } 1166 1167 /* --------------------------------------------------------------------- */ 1168 1169 /* 1170 * Change size of the given vnode. 1171 * Caller should execute tmpfs_update on vp after a successful execution. 1172 * The vnode must be locked on entry and remain locked on exit. 1173 */ 1174 int 1175 tmpfs_chsize(struct vnode *vp, u_quad_t size, struct ucred *cred) 1176 { 1177 int error; 1178 struct tmpfs_node *node; 1179 1180 KKASSERT(vn_islocked(vp)); 1181 1182 node = VP_TO_TMPFS_NODE(vp); 1183 1184 /* Decide whether this is a valid operation based on the file type. */ 1185 error = 0; 1186 switch (vp->v_type) { 1187 case VDIR: 1188 return EISDIR; 1189 1190 case VREG: 1191 if (vp->v_mount->mnt_flag & MNT_RDONLY) 1192 return EROFS; 1193 break; 1194 1195 case VBLK: 1196 /* FALLTHROUGH */ 1197 case VCHR: 1198 /* FALLTHROUGH */ 1199 case VFIFO: 1200 /* Allow modifications of special files even if in the file 1201 * system is mounted read-only (we are not modifying the 1202 * files themselves, but the objects they represent). */ 1203 return 0; 1204 1205 default: 1206 /* Anything else is unsupported. */ 1207 return EOPNOTSUPP; 1208 } 1209 1210 /* Immutable or append-only files cannot be modified, either. */ 1211 if (node->tn_flags & (IMMUTABLE | APPEND)) 1212 return EPERM; 1213 1214 error = tmpfs_truncate(vp, size); 1215 /* tmpfs_truncate will raise the NOTE_EXTEND and NOTE_ATTRIB kevents 1216 * for us, as will update tn_status; no need to do that here. */ 1217 1218 KKASSERT(vn_islocked(vp)); 1219 1220 return error; 1221 } 1222 1223 /* --------------------------------------------------------------------- */ 1224 1225 /* 1226 * Change access and modification times of the given vnode. 1227 * Caller should execute tmpfs_update on vp after a successful execution. 1228 * The vnode must be locked on entry and remain locked on exit. 1229 */ 1230 int 1231 tmpfs_chtimes(struct vnode *vp, struct timespec *atime, struct timespec *mtime, 1232 int vaflags, struct ucred *cred) 1233 { 1234 struct tmpfs_node *node; 1235 1236 KKASSERT(vn_islocked(vp)); 1237 1238 node = VP_TO_TMPFS_NODE(vp); 1239 1240 /* Disallow this operation if the file system is mounted read-only. */ 1241 if (vp->v_mount->mnt_flag & MNT_RDONLY) 1242 return EROFS; 1243 1244 /* Immutable or append-only files cannot be modified, either. */ 1245 if (node->tn_flags & (IMMUTABLE | APPEND)) 1246 return EPERM; 1247 1248 TMPFS_NODE_LOCK(node); 1249 if (atime->tv_sec != VNOVAL && atime->tv_nsec != VNOVAL) 1250 node->tn_status |= TMPFS_NODE_ACCESSED; 1251 1252 if (mtime->tv_sec != VNOVAL && mtime->tv_nsec != VNOVAL) { 1253 node->tn_status |= TMPFS_NODE_MODIFIED; 1254 vclrflags(vp, VLASTWRITETS); 1255 } 1256 1257 TMPFS_NODE_UNLOCK(node); 1258 1259 tmpfs_itimes(vp, atime, mtime); 1260 1261 KKASSERT(vn_islocked(vp)); 1262 1263 return 0; 1264 } 1265 1266 /* --------------------------------------------------------------------- */ 1267 /* Sync timestamps */ 1268 void 1269 tmpfs_itimes(struct vnode *vp, const struct timespec *acc, 1270 const struct timespec *mod) 1271 { 1272 struct tmpfs_node *node; 1273 struct timespec now; 1274 1275 node = VP_TO_TMPFS_NODE(vp); 1276 1277 if ((node->tn_status & (TMPFS_NODE_ACCESSED | TMPFS_NODE_MODIFIED | 1278 TMPFS_NODE_CHANGED)) == 0) 1279 return; 1280 1281 vfs_timestamp(&now); 1282 1283 TMPFS_NODE_LOCK(node); 1284 if (node->tn_status & TMPFS_NODE_ACCESSED) { 1285 if (acc == NULL) 1286 acc = &now; 1287 node->tn_atime = acc->tv_sec; 1288 node->tn_atimensec = acc->tv_nsec; 1289 } 1290 if (node->tn_status & TMPFS_NODE_MODIFIED) { 1291 if (mod == NULL) 1292 mod = &now; 1293 node->tn_mtime = mod->tv_sec; 1294 node->tn_mtimensec = mod->tv_nsec; 1295 } 1296 if (node->tn_status & TMPFS_NODE_CHANGED) { 1297 node->tn_ctime = now.tv_sec; 1298 node->tn_ctimensec = now.tv_nsec; 1299 } 1300 1301 node->tn_status &= ~(TMPFS_NODE_ACCESSED | 1302 TMPFS_NODE_MODIFIED | 1303 TMPFS_NODE_CHANGED); 1304 TMPFS_NODE_UNLOCK(node); 1305 } 1306 1307 /* --------------------------------------------------------------------- */ 1308 1309 void 1310 tmpfs_update(struct vnode *vp) 1311 { 1312 tmpfs_itimes(vp, NULL, NULL); 1313 } 1314 1315 /* --------------------------------------------------------------------- */ 1316 1317 /* 1318 * Caller must hold an exclusive node lock. 1319 */ 1320 int 1321 tmpfs_truncate(struct vnode *vp, off_t length) 1322 { 1323 int error; 1324 struct tmpfs_node *node; 1325 1326 node = VP_TO_TMPFS_NODE(vp); 1327 1328 if (length < 0) { 1329 error = EINVAL; 1330 goto out; 1331 } 1332 1333 if (node->tn_size == length) { 1334 error = 0; 1335 goto out; 1336 } 1337 1338 if (length > VFS_TO_TMPFS(vp->v_mount)->tm_maxfilesize) 1339 return (EFBIG); 1340 1341 1342 error = tmpfs_reg_resize(vp, length, 1); 1343 1344 if (error == 0) 1345 node->tn_status |= TMPFS_NODE_CHANGED | TMPFS_NODE_MODIFIED; 1346 1347 out: 1348 tmpfs_update(vp); 1349 1350 return error; 1351 } 1352 1353 /* --------------------------------------------------------------------- */ 1354 1355 static ino_t 1356 tmpfs_fetch_ino(struct tmpfs_mount *tmp) 1357 { 1358 ino_t ret; 1359 1360 TMPFS_LOCK(tmp); 1361 ret = tmp->tm_ino++; 1362 TMPFS_UNLOCK(tmp); 1363 1364 return (ret); 1365 } 1366 1367 static int 1368 tmpfs_dirtree_compare(struct tmpfs_dirent *a, struct tmpfs_dirent *b) 1369 { 1370 if (a->td_namelen > b->td_namelen) 1371 return 1; 1372 else if (a->td_namelen < b->td_namelen) 1373 return -1; 1374 else 1375 return strncmp(a->td_name, b->td_name, a->td_namelen); 1376 } 1377 1378 static int 1379 tmpfs_dirtree_compare_cookie(struct tmpfs_dirent *a, struct tmpfs_dirent *b) 1380 { 1381 if (a < b) 1382 return(-1); 1383 if (a > b) 1384 return(1); 1385 return 0; 1386 } 1387