tmpfs_subr.c revision 1.56.4.3
1 /* $NetBSD: tmpfs_subr.c,v 1.56.4.3 2011/03/05 20:55:09 rmind Exp $ */ 2 3 /* 4 * Copyright (c) 2005, 2006, 2007 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/cdefs.h> 38 __KERNEL_RCSID(0, "$NetBSD: tmpfs_subr.c,v 1.56.4.3 2011/03/05 20:55:09 rmind Exp $"); 39 40 #include <sys/param.h> 41 #include <sys/dirent.h> 42 #include <sys/event.h> 43 #include <sys/kmem.h> 44 #include <sys/mount.h> 45 #include <sys/namei.h> 46 #include <sys/time.h> 47 #include <sys/stat.h> 48 #include <sys/systm.h> 49 #include <sys/swap.h> 50 #include <sys/vnode.h> 51 #include <sys/kauth.h> 52 #include <sys/proc.h> 53 #include <sys/atomic.h> 54 55 #include <uvm/uvm.h> 56 57 #include <miscfs/specfs/specdev.h> 58 #include <miscfs/genfs/genfs.h> 59 #include <fs/tmpfs/tmpfs.h> 60 #include <fs/tmpfs/tmpfs_fifoops.h> 61 #include <fs/tmpfs/tmpfs_specops.h> 62 #include <fs/tmpfs/tmpfs_vnops.h> 63 64 /* --------------------------------------------------------------------- */ 65 66 /* 67 * Allocates a new node of type 'type' inside the 'tmp' mount point, with 68 * its owner set to 'uid', its group to 'gid' and its mode set to 'mode', 69 * using the credentials of the process 'p'. 70 * 71 * If the node type is set to 'VDIR', then the parent parameter must point 72 * to the parent directory of the node being created. It may only be NULL 73 * while allocating the root node. 74 * 75 * If the node type is set to 'VBLK' or 'VCHR', then the rdev parameter 76 * specifies the device the node represents. 77 * 78 * If the node type is set to 'VLNK', then the parameter target specifies 79 * the file name of the target file for the symbolic link that is being 80 * created. 81 * 82 * Note that new nodes are retrieved from the available list if it has 83 * items or, if it is empty, from the node pool as long as there is enough 84 * space to create them. 85 * 86 * Returns zero on success or an appropriate error code on failure. 87 */ 88 int 89 tmpfs_alloc_node(struct tmpfs_mount *tmp, enum vtype type, 90 uid_t uid, gid_t gid, mode_t mode, struct tmpfs_node *parent, 91 char *target, dev_t rdev, struct tmpfs_node **node) 92 { 93 struct tmpfs_node *nnode; 94 95 /* If the root directory of the 'tmp' file system is not yet 96 * allocated, this must be the request to do it. */ 97 KASSERT(IMPLIES(tmp->tm_root == NULL, parent == NULL && type == VDIR)); 98 99 KASSERT(IFF(type == VLNK, target != NULL)); 100 KASSERT(IFF(type == VBLK || type == VCHR, rdev != VNOVAL)); 101 102 KASSERT(uid != VNOVAL && gid != VNOVAL && mode != VNOVAL); 103 104 nnode = NULL; 105 if (atomic_inc_uint_nv(&tmp->tm_nodes_cnt) >= tmp->tm_nodes_max) { 106 atomic_dec_uint(&tmp->tm_nodes_cnt); 107 return ENOSPC; 108 } 109 110 nnode = tmpfs_node_get(tmp); 111 if (nnode == NULL) { 112 atomic_dec_uint(&tmp->tm_nodes_cnt); 113 return ENOSPC; 114 } 115 116 /* 117 * XXX Where the pool is backed by a map larger than (4GB * 118 * sizeof(*nnode)), this may produce duplicate inode numbers 119 * for applications that do not understand 64-bit ino_t. 120 */ 121 nnode->tn_id = (ino_t)((uintptr_t)nnode / sizeof(*nnode)); 122 nnode->tn_gen = arc4random(); 123 124 /* Generic initialization. */ 125 nnode->tn_type = type; 126 nnode->tn_size = 0; 127 nnode->tn_status = 0; 128 nnode->tn_flags = 0; 129 nnode->tn_links = 0; 130 131 vfs_timestamp(&nnode->tn_atime); 132 nnode->tn_birthtime = nnode->tn_atime; 133 nnode->tn_ctime = nnode->tn_atime; 134 nnode->tn_mtime = nnode->tn_atime; 135 136 nnode->tn_uid = uid; 137 nnode->tn_gid = gid; 138 nnode->tn_mode = mode; 139 nnode->tn_lockf = NULL; 140 nnode->tn_vnode = NULL; 141 142 /* Type-specific initialization. */ 143 switch (nnode->tn_type) { 144 case VBLK: 145 case VCHR: 146 nnode->tn_spec.tn_dev.tn_rdev = rdev; 147 break; 148 149 case VDIR: 150 TAILQ_INIT(&nnode->tn_spec.tn_dir.tn_dir); 151 nnode->tn_spec.tn_dir.tn_parent = 152 (parent == NULL) ? nnode : parent; 153 nnode->tn_spec.tn_dir.tn_readdir_lastn = 0; 154 nnode->tn_spec.tn_dir.tn_readdir_lastp = NULL; 155 nnode->tn_links++; 156 break; 157 158 case VFIFO: 159 /* FALLTHROUGH */ 160 case VSOCK: 161 break; 162 163 case VLNK: 164 KASSERT(strlen(target) < MAXPATHLEN); 165 nnode->tn_size = strlen(target); 166 nnode->tn_spec.tn_lnk.tn_link = 167 tmpfs_strname_alloc(tmp, nnode->tn_size); 168 if (nnode->tn_spec.tn_lnk.tn_link == NULL) { 169 atomic_dec_uint(&tmp->tm_nodes_cnt); 170 tmpfs_node_put(tmp, nnode); 171 return ENOSPC; 172 } 173 memcpy(nnode->tn_spec.tn_lnk.tn_link, target, nnode->tn_size); 174 break; 175 176 case VREG: 177 nnode->tn_spec.tn_reg.tn_aobj = 178 uao_create(INT32_MAX - PAGE_SIZE, 0); 179 nnode->tn_spec.tn_reg.tn_aobj_pages = 0; 180 break; 181 182 default: 183 KASSERT(0); 184 } 185 186 mutex_init(&nnode->tn_vlock, MUTEX_DEFAULT, IPL_NONE); 187 188 mutex_enter(&tmp->tm_lock); 189 LIST_INSERT_HEAD(&tmp->tm_nodes, nnode, tn_entries); 190 mutex_exit(&tmp->tm_lock); 191 192 *node = nnode; 193 return 0; 194 } 195 196 /* --------------------------------------------------------------------- */ 197 198 /* 199 * Destroys the node pointed to by node from the file system 'tmp'. 200 * If the node does not belong to the given mount point, the results are 201 * unpredicted. 202 * 203 * If the node references a directory; no entries are allowed because 204 * their removal could need a recursive algorithm, something forbidden in 205 * kernel space. Furthermore, there is not need to provide such 206 * functionality (recursive removal) because the only primitives offered 207 * to the user are the removal of empty directories and the deletion of 208 * individual files. 209 * 210 * Note that nodes are not really deleted; in fact, when a node has been 211 * allocated, it cannot be deleted during the whole life of the file 212 * system. Instead, they are moved to the available list and remain there 213 * until reused. 214 */ 215 void 216 tmpfs_free_node(struct tmpfs_mount *tmp, struct tmpfs_node *node) 217 { 218 size_t objsz; 219 220 mutex_enter(&tmp->tm_lock); 221 LIST_REMOVE(node, tn_entries); 222 mutex_exit(&tmp->tm_lock); 223 atomic_dec_uint(&tmp->tm_nodes_cnt); 224 225 switch (node->tn_type) { 226 case VLNK: 227 tmpfs_strname_free(tmp, node->tn_spec.tn_lnk.tn_link, 228 node->tn_size); 229 break; 230 case VREG: 231 /* 232 * Calculate the size of node data, decrease the used-memory 233 * counter, and destroy the memory object (if any). 234 */ 235 objsz = PAGE_SIZE * node->tn_spec.tn_reg.tn_aobj_pages; 236 if (objsz != 0) { 237 tmpfs_mem_decr(tmp, objsz); 238 } 239 if (node->tn_spec.tn_reg.tn_aobj != NULL) { 240 uao_detach(node->tn_spec.tn_reg.tn_aobj); 241 } 242 break; 243 default: 244 break; 245 } 246 247 mutex_destroy(&node->tn_vlock); 248 tmpfs_node_put(tmp, node); 249 } 250 251 /* --------------------------------------------------------------------- */ 252 253 /* 254 * Allocates a new directory entry for the node node with a name of name. 255 * The new directory entry is returned in *de. 256 * 257 * The link count of node is increased by one to reflect the new object 258 * referencing it. This takes care of notifying kqueue listeners about 259 * this change. 260 * 261 * Returns zero on success or an appropriate error code on failure. 262 */ 263 int 264 tmpfs_alloc_dirent(struct tmpfs_mount *tmp, struct tmpfs_node *node, 265 const char *name, uint16_t len, struct tmpfs_dirent **de) 266 { 267 struct tmpfs_dirent *nde; 268 269 nde = tmpfs_dirent_get(tmp); 270 if (nde == NULL) 271 return ENOSPC; 272 273 nde->td_name = tmpfs_strname_alloc(tmp, len); 274 if (nde->td_name == NULL) { 275 tmpfs_dirent_put(tmp, nde); 276 return ENOSPC; 277 } 278 nde->td_namelen = len; 279 memcpy(nde->td_name, name, len); 280 nde->td_node = node; 281 282 if (node != TMPFS_NODE_WHITEOUT) { 283 node->tn_links++; 284 if (node->tn_links > 1 && node->tn_vnode != NULL) 285 VN_KNOTE(node->tn_vnode, NOTE_LINK); 286 } 287 *de = nde; 288 289 return 0; 290 } 291 292 /* --------------------------------------------------------------------- */ 293 294 /* 295 * Frees a directory entry. It is the caller's responsibility to destroy 296 * the node referenced by it if needed. 297 * 298 * The link count of node is decreased by one to reflect the removal of an 299 * object that referenced it. This only happens if 'node_exists' is true; 300 * otherwise the function will not access the node referred to by the 301 * directory entry, as it may already have been released from the outside. 302 * 303 * Interested parties (kqueue) are notified of the link count change; note 304 * that this can include both the node pointed to by the directory entry 305 * as well as its parent. 306 */ 307 void 308 tmpfs_free_dirent(struct tmpfs_mount *tmp, struct tmpfs_dirent *de, 309 bool node_exists) 310 { 311 if (node_exists && de->td_node != TMPFS_NODE_WHITEOUT) { 312 struct tmpfs_node *node; 313 314 node = de->td_node; 315 316 KASSERT(node->tn_links > 0); 317 node->tn_links--; 318 if (node->tn_vnode != NULL) 319 VN_KNOTE(node->tn_vnode, node->tn_links == 0 ? 320 NOTE_DELETE : NOTE_LINK); 321 if (node->tn_type == VDIR) 322 VN_KNOTE(node->tn_spec.tn_dir.tn_parent->tn_vnode, 323 NOTE_LINK); 324 } 325 326 tmpfs_strname_free(tmp, de->td_name, de->td_namelen); 327 tmpfs_dirent_put(tmp, de); 328 } 329 330 /* --------------------------------------------------------------------- */ 331 332 /* 333 * Allocates a new vnode for the node node or returns a new reference to 334 * an existing one if the node had already a vnode referencing it. The 335 * resulting locked vnode is returned in *vpp. 336 * 337 * Returns zero on success or an appropriate error code on failure. 338 */ 339 int 340 tmpfs_alloc_vp(struct mount *mp, struct tmpfs_node *node, struct vnode **vpp) 341 { 342 int error; 343 struct vnode *vp; 344 345 /* If there is already a vnode, then lock it. */ 346 for (;;) { 347 mutex_enter(&node->tn_vlock); 348 if ((vp = node->tn_vnode) != NULL) { 349 mutex_enter(vp->v_interlock); 350 mutex_exit(&node->tn_vlock); 351 error = vget(vp, LK_EXCLUSIVE); 352 if (error == ENOENT) { 353 /* vnode was reclaimed. */ 354 continue; 355 } 356 *vpp = vp; 357 return error; 358 } 359 break; 360 } 361 362 /* Get a new vnode and associate it with our node. */ 363 error = getnewvnode(VT_TMPFS, mp, tmpfs_vnodeop_p, &vp); 364 if (error != 0) { 365 mutex_exit(&node->tn_vlock); 366 return error; 367 } 368 369 error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 370 if (error != 0) { 371 mutex_exit(&node->tn_vlock); 372 ungetnewvnode(vp); 373 return error; 374 } 375 376 vp->v_type = node->tn_type; 377 378 /* Type-specific initialization. */ 379 switch (node->tn_type) { 380 case VBLK: 381 /* FALLTHROUGH */ 382 case VCHR: 383 vp->v_op = tmpfs_specop_p; 384 spec_node_init(vp, node->tn_spec.tn_dev.tn_rdev); 385 break; 386 387 case VDIR: 388 vp->v_vflag |= node->tn_spec.tn_dir.tn_parent == node ? 389 VV_ROOT : 0; 390 break; 391 392 case VFIFO: 393 vp->v_op = tmpfs_fifoop_p; 394 break; 395 396 case VLNK: 397 /* FALLTHROUGH */ 398 case VREG: 399 /* FALLTHROUGH */ 400 case VSOCK: 401 break; 402 403 default: 404 KASSERT(0); 405 } 406 407 uvm_vnp_setsize(vp, node->tn_size); 408 vp->v_data = node; 409 node->tn_vnode = vp; 410 mutex_exit(&node->tn_vlock); 411 *vpp = vp; 412 413 KASSERT(IFF(error == 0, *vpp != NULL && VOP_ISLOCKED(*vpp))); 414 KASSERT(*vpp == node->tn_vnode); 415 416 return error; 417 } 418 419 /* --------------------------------------------------------------------- */ 420 421 /* 422 * Destroys the association between the vnode vp and the node it 423 * references. 424 */ 425 void 426 tmpfs_free_vp(struct vnode *vp) 427 { 428 struct tmpfs_node *node; 429 430 node = VP_TO_TMPFS_NODE(vp); 431 432 mutex_enter(&node->tn_vlock); 433 node->tn_vnode = NULL; 434 mutex_exit(&node->tn_vlock); 435 vp->v_data = NULL; 436 } 437 438 /* --------------------------------------------------------------------- */ 439 440 /* 441 * Allocates a new file of type 'type' and adds it to the parent directory 442 * 'dvp'; this addition is done using the component name given in 'cnp'. 443 * The ownership of the new file is automatically assigned based on the 444 * credentials of the caller (through 'cnp'), the group is set based on 445 * the parent directory and the mode is determined from the 'vap' argument. 446 * If successful, *vpp holds a vnode to the newly created file and zero 447 * is returned. Otherwise *vpp is NULL and the function returns an 448 * appropriate error code. 449 */ 450 int 451 tmpfs_alloc_file(struct vnode *dvp, struct vnode **vpp, struct vattr *vap, 452 struct componentname *cnp, char *target) 453 { 454 int error; 455 struct tmpfs_dirent *de; 456 struct tmpfs_mount *tmp; 457 struct tmpfs_node *dnode; 458 struct tmpfs_node *node; 459 struct tmpfs_node *parent; 460 461 KASSERT(VOP_ISLOCKED(dvp)); 462 463 tmp = VFS_TO_TMPFS(dvp->v_mount); 464 dnode = VP_TO_TMPFS_DIR(dvp); 465 *vpp = NULL; 466 467 /* If the entry we are creating is a directory, we cannot overflow 468 * the number of links of its parent, because it will get a new 469 * link. */ 470 if (vap->va_type == VDIR) { 471 /* Ensure that we do not overflow the maximum number of links 472 * imposed by the system. */ 473 KASSERT(dnode->tn_links <= LINK_MAX); 474 if (dnode->tn_links == LINK_MAX) { 475 error = EMLINK; 476 goto out; 477 } 478 479 parent = dnode; 480 } else 481 parent = NULL; 482 483 /* Allocate a node that represents the new file. */ 484 error = tmpfs_alloc_node(tmp, vap->va_type, kauth_cred_geteuid(cnp->cn_cred), 485 dnode->tn_gid, vap->va_mode, parent, target, vap->va_rdev, &node); 486 if (error != 0) 487 goto out; 488 489 /* Allocate a directory entry that points to the new file. */ 490 error = tmpfs_alloc_dirent(tmp, node, cnp->cn_nameptr, cnp->cn_namelen, 491 &de); 492 if (error != 0) { 493 tmpfs_free_node(tmp, node); 494 goto out; 495 } 496 497 /* Allocate a vnode for the new file. */ 498 error = tmpfs_alloc_vp(dvp->v_mount, node, vpp); 499 if (error != 0) { 500 tmpfs_free_dirent(tmp, de, true); 501 tmpfs_free_node(tmp, node); 502 goto out; 503 } 504 505 /* Now that all required items are allocated, we can proceed to 506 * insert the new node into the directory, an operation that 507 * cannot fail. */ 508 tmpfs_dir_attach(dvp, de); 509 if (vap->va_type == VDIR) { 510 VN_KNOTE(dvp, NOTE_LINK); 511 dnode->tn_links++; 512 KASSERT(dnode->tn_links <= LINK_MAX); 513 } 514 515 out: 516 vput(dvp); 517 518 KASSERT(IFF(error == 0, *vpp != NULL)); 519 520 return error; 521 } 522 523 /* --------------------------------------------------------------------- */ 524 525 /* 526 * Attaches the directory entry de to the directory represented by vp. 527 * Note that this does not change the link count of the node pointed by 528 * the directory entry, as this is done by tmpfs_alloc_dirent. 529 * 530 * As the "parent" directory changes, interested parties are notified of 531 * a write to it. 532 */ 533 void 534 tmpfs_dir_attach(struct vnode *vp, struct tmpfs_dirent *de) 535 { 536 struct tmpfs_node *dnode; 537 538 KASSERT(VOP_ISLOCKED(vp)); 539 dnode = VP_TO_TMPFS_DIR(vp); 540 541 TAILQ_INSERT_TAIL(&dnode->tn_spec.tn_dir.tn_dir, de, td_entries); 542 dnode->tn_size += sizeof(struct tmpfs_dirent); 543 dnode->tn_status |= TMPFS_NODE_ACCESSED | TMPFS_NODE_CHANGED | \ 544 TMPFS_NODE_MODIFIED; 545 uvm_vnp_setsize(vp, dnode->tn_size); 546 547 VN_KNOTE(vp, NOTE_WRITE); 548 } 549 550 /* --------------------------------------------------------------------- */ 551 552 /* 553 * Detaches the directory entry de from the directory represented by vp. 554 * Note that this does not change the link count of the node pointed by 555 * the directory entry, as this is done by tmpfs_free_dirent. 556 * 557 * As the "parent" directory changes, interested parties are notified of 558 * a write to it. 559 */ 560 void 561 tmpfs_dir_detach(struct vnode *vp, struct tmpfs_dirent *de) 562 { 563 struct tmpfs_node *dnode; 564 565 KASSERT(VOP_ISLOCKED(vp)); 566 dnode = VP_TO_TMPFS_DIR(vp); 567 568 if (dnode->tn_spec.tn_dir.tn_readdir_lastp == de) { 569 dnode->tn_spec.tn_dir.tn_readdir_lastn = 0; 570 dnode->tn_spec.tn_dir.tn_readdir_lastp = NULL; 571 } 572 573 TAILQ_REMOVE(&dnode->tn_spec.tn_dir.tn_dir, de, td_entries); 574 dnode->tn_size -= sizeof(struct tmpfs_dirent); 575 dnode->tn_status |= TMPFS_NODE_ACCESSED | TMPFS_NODE_CHANGED | \ 576 TMPFS_NODE_MODIFIED; 577 uvm_vnp_setsize(vp, dnode->tn_size); 578 579 VN_KNOTE(vp, NOTE_WRITE); 580 } 581 582 /* --------------------------------------------------------------------- */ 583 584 /* 585 * Looks for a directory entry in the directory represented by node. 586 * 'cnp' describes the name of the entry to look for. Note that the . 587 * and .. components are not allowed as they do not physically exist 588 * within directories. 589 * 590 * Returns a pointer to the entry when found, otherwise NULL. 591 */ 592 struct tmpfs_dirent * 593 tmpfs_dir_lookup(struct tmpfs_node *node, struct componentname *cnp) 594 { 595 struct tmpfs_dirent *de; 596 597 KASSERT(VOP_ISLOCKED(node->tn_vnode)); 598 KASSERT(IMPLIES(cnp->cn_namelen == 1, cnp->cn_nameptr[0] != '.')); 599 KASSERT(IMPLIES(cnp->cn_namelen == 2, !(cnp->cn_nameptr[0] == '.' && 600 cnp->cn_nameptr[1] == '.'))); 601 TMPFS_VALIDATE_DIR(node); 602 603 node->tn_status |= TMPFS_NODE_ACCESSED; 604 605 TAILQ_FOREACH(de, &node->tn_spec.tn_dir.tn_dir, td_entries) { 606 KASSERT(cnp->cn_namelen < 0xffff); 607 if (de->td_namelen == (uint16_t)cnp->cn_namelen && 608 memcmp(de->td_name, cnp->cn_nameptr, de->td_namelen) == 0) { 609 break; 610 } 611 } 612 613 return de; 614 } 615 616 /* --------------------------------------------------------------------- */ 617 618 /* 619 * Helper function for tmpfs_readdir. Creates a '.' entry for the given 620 * directory and returns it in the uio space. The function returns 0 621 * on success, -1 if there was not enough space in the uio structure to 622 * hold the directory entry or an appropriate error code if another 623 * error happens. 624 */ 625 int 626 tmpfs_dir_getdotdent(struct tmpfs_node *node, struct uio *uio) 627 { 628 int error; 629 struct dirent *dentp; 630 631 TMPFS_VALIDATE_DIR(node); 632 KASSERT(uio->uio_offset == TMPFS_DIRCOOKIE_DOT); 633 634 dentp = kmem_alloc(sizeof(struct dirent), KM_SLEEP); 635 636 dentp->d_fileno = node->tn_id; 637 dentp->d_type = DT_DIR; 638 dentp->d_namlen = 1; 639 dentp->d_name[0] = '.'; 640 dentp->d_name[1] = '\0'; 641 dentp->d_reclen = _DIRENT_SIZE(dentp); 642 643 if (dentp->d_reclen > uio->uio_resid) 644 error = -1; 645 else { 646 error = uiomove(dentp, dentp->d_reclen, uio); 647 if (error == 0) 648 uio->uio_offset = TMPFS_DIRCOOKIE_DOTDOT; 649 } 650 651 node->tn_status |= TMPFS_NODE_ACCESSED; 652 653 kmem_free(dentp, sizeof(struct dirent)); 654 return error; 655 } 656 657 /* --------------------------------------------------------------------- */ 658 659 /* 660 * Helper function for tmpfs_readdir. Creates a '..' entry for the given 661 * directory and returns it in the uio space. The function returns 0 662 * on success, -1 if there was not enough space in the uio structure to 663 * hold the directory entry or an appropriate error code if another 664 * error happens. 665 */ 666 int 667 tmpfs_dir_getdotdotdent(struct tmpfs_node *node, struct uio *uio) 668 { 669 int error; 670 struct dirent *dentp; 671 672 TMPFS_VALIDATE_DIR(node); 673 KASSERT(uio->uio_offset == TMPFS_DIRCOOKIE_DOTDOT); 674 675 dentp = kmem_alloc(sizeof(struct dirent), KM_SLEEP); 676 677 dentp->d_fileno = node->tn_spec.tn_dir.tn_parent->tn_id; 678 dentp->d_type = DT_DIR; 679 dentp->d_namlen = 2; 680 dentp->d_name[0] = '.'; 681 dentp->d_name[1] = '.'; 682 dentp->d_name[2] = '\0'; 683 dentp->d_reclen = _DIRENT_SIZE(dentp); 684 685 if (dentp->d_reclen > uio->uio_resid) 686 error = -1; 687 else { 688 error = uiomove(dentp, dentp->d_reclen, uio); 689 if (error == 0) { 690 struct tmpfs_dirent *de; 691 692 de = TAILQ_FIRST(&node->tn_spec.tn_dir.tn_dir); 693 if (de == NULL) 694 uio->uio_offset = TMPFS_DIRCOOKIE_EOF; 695 else 696 uio->uio_offset = tmpfs_dircookie(de); 697 } 698 } 699 700 node->tn_status |= TMPFS_NODE_ACCESSED; 701 702 kmem_free(dentp, sizeof(struct dirent)); 703 return error; 704 } 705 706 /* --------------------------------------------------------------------- */ 707 708 /* 709 * Lookup a directory entry by its associated cookie. 710 */ 711 struct tmpfs_dirent * 712 tmpfs_dir_lookupbycookie(struct tmpfs_node *node, off_t cookie) 713 { 714 struct tmpfs_dirent *de; 715 716 KASSERT(VOP_ISLOCKED(node->tn_vnode)); 717 718 if (cookie == node->tn_spec.tn_dir.tn_readdir_lastn && 719 node->tn_spec.tn_dir.tn_readdir_lastp != NULL) { 720 return node->tn_spec.tn_dir.tn_readdir_lastp; 721 } 722 723 TAILQ_FOREACH(de, &node->tn_spec.tn_dir.tn_dir, td_entries) { 724 if (tmpfs_dircookie(de) == cookie) { 725 break; 726 } 727 } 728 729 return de; 730 } 731 732 /* --------------------------------------------------------------------- */ 733 734 /* 735 * Helper function for tmpfs_readdir. Returns as much directory entries 736 * as can fit in the uio space. The read starts at uio->uio_offset. 737 * The function returns 0 on success, -1 if there was not enough space 738 * in the uio structure to hold the directory entry or an appropriate 739 * error code if another error happens. 740 */ 741 int 742 tmpfs_dir_getdents(struct tmpfs_node *node, struct uio *uio, off_t *cntp) 743 { 744 int error; 745 off_t startcookie; 746 struct dirent *dentp; 747 struct tmpfs_dirent *de; 748 749 KASSERT(VOP_ISLOCKED(node->tn_vnode)); 750 TMPFS_VALIDATE_DIR(node); 751 752 /* Locate the first directory entry we have to return. We have cached 753 * the last readdir in the node, so use those values if appropriate. 754 * Otherwise do a linear scan to find the requested entry. */ 755 startcookie = uio->uio_offset; 756 KASSERT(startcookie != TMPFS_DIRCOOKIE_DOT); 757 KASSERT(startcookie != TMPFS_DIRCOOKIE_DOTDOT); 758 if (startcookie == TMPFS_DIRCOOKIE_EOF) { 759 return 0; 760 } else { 761 de = tmpfs_dir_lookupbycookie(node, startcookie); 762 } 763 if (de == NULL) { 764 return EINVAL; 765 } 766 767 dentp = kmem_alloc(sizeof(struct dirent), KM_SLEEP); 768 769 /* Read as much entries as possible; i.e., until we reach the end of 770 * the directory or we exhaust uio space. */ 771 do { 772 /* Create a dirent structure representing the current 773 * tmpfs_node and fill it. */ 774 if (de->td_node == TMPFS_NODE_WHITEOUT) { 775 dentp->d_fileno = 1; 776 dentp->d_type = DT_WHT; 777 } else { 778 dentp->d_fileno = de->td_node->tn_id; 779 switch (de->td_node->tn_type) { 780 case VBLK: 781 dentp->d_type = DT_BLK; 782 break; 783 784 case VCHR: 785 dentp->d_type = DT_CHR; 786 break; 787 788 case VDIR: 789 dentp->d_type = DT_DIR; 790 break; 791 792 case VFIFO: 793 dentp->d_type = DT_FIFO; 794 break; 795 796 case VLNK: 797 dentp->d_type = DT_LNK; 798 break; 799 800 case VREG: 801 dentp->d_type = DT_REG; 802 break; 803 804 case VSOCK: 805 dentp->d_type = DT_SOCK; 806 break; 807 808 default: 809 KASSERT(0); 810 } 811 } 812 dentp->d_namlen = de->td_namelen; 813 KASSERT(de->td_namelen < sizeof(dentp->d_name)); 814 (void)memcpy(dentp->d_name, de->td_name, de->td_namelen); 815 dentp->d_name[de->td_namelen] = '\0'; 816 dentp->d_reclen = _DIRENT_SIZE(dentp); 817 818 /* Stop reading if the directory entry we are treating is 819 * bigger than the amount of data that can be returned. */ 820 if (dentp->d_reclen > uio->uio_resid) { 821 error = -1; 822 break; 823 } 824 825 /* Copy the new dirent structure into the output buffer and 826 * advance pointers. */ 827 error = uiomove(dentp, dentp->d_reclen, uio); 828 829 (*cntp)++; 830 de = TAILQ_NEXT(de, td_entries); 831 } while (error == 0 && uio->uio_resid > 0 && de != NULL); 832 833 /* Update the offset and cache. */ 834 if (de == NULL) { 835 uio->uio_offset = TMPFS_DIRCOOKIE_EOF; 836 node->tn_spec.tn_dir.tn_readdir_lastn = 0; 837 node->tn_spec.tn_dir.tn_readdir_lastp = NULL; 838 } else { 839 node->tn_spec.tn_dir.tn_readdir_lastn = uio->uio_offset = 840 tmpfs_dircookie(de); 841 node->tn_spec.tn_dir.tn_readdir_lastp = de; 842 } 843 844 node->tn_status |= TMPFS_NODE_ACCESSED; 845 846 kmem_free(dentp, sizeof(struct dirent)); 847 return error; 848 } 849 850 /* --------------------------------------------------------------------- */ 851 852 /* 853 * Resizes the aobj associated to the regular file pointed to by vp to 854 * the size newsize. 'vp' must point to a vnode that represents a regular 855 * file. 'newsize' must be positive. 856 * 857 * If the file is extended, the appropriate kevent is raised. This does 858 * not rise a write event though because resizing is not the same as 859 * writing. 860 * 861 * Returns zero on success or an appropriate error code on failure. 862 */ 863 int 864 tmpfs_reg_resize(struct vnode *vp, off_t newsize) 865 { 866 size_t newpages, oldpages; 867 struct tmpfs_mount *tmp; 868 struct tmpfs_node *node; 869 off_t oldsize; 870 871 KASSERT(vp->v_type == VREG); 872 KASSERT(newsize >= 0); 873 874 node = VP_TO_TMPFS_NODE(vp); 875 tmp = VFS_TO_TMPFS(vp->v_mount); 876 877 oldsize = node->tn_size; 878 oldpages = round_page(oldsize) >> PAGE_SHIFT; 879 newpages = round_page(newsize) >> PAGE_SHIFT; 880 KASSERT(oldpages == node->tn_spec.tn_reg.tn_aobj_pages); 881 882 if (newpages > oldpages) { 883 /* Increase the used-memory counter if getting extra pages. */ 884 if (!tmpfs_mem_incr(tmp, (newpages - oldpages) << PAGE_SHIFT)) { 885 return ENOSPC; 886 } 887 } else if (newsize < oldsize) { 888 int zerolen = MIN(round_page(newsize), node->tn_size) - newsize; 889 890 /* Zero out the truncated part of the last page. */ 891 uvm_vnp_zerorange(vp, newsize, zerolen); 892 } 893 894 node->tn_spec.tn_reg.tn_aobj_pages = newpages; 895 node->tn_size = newsize; 896 uvm_vnp_setsize(vp, newsize); 897 898 /* 899 * Free "backing store". 900 */ 901 if (newpages < oldpages) { 902 struct uvm_object *uobj; 903 904 uobj = node->tn_spec.tn_reg.tn_aobj; 905 906 mutex_enter(uobj->vmobjlock); 907 uao_dropswap_range(uobj, newpages, oldpages); 908 mutex_exit(uobj->vmobjlock); 909 910 /* Decrease the used-memory counter. */ 911 tmpfs_mem_decr(tmp, (oldpages - newpages) << PAGE_SHIFT); 912 } 913 914 if (newsize > oldsize) 915 VN_KNOTE(vp, NOTE_EXTEND); 916 917 return 0; 918 } 919 920 /* 921 * Change flags of the given vnode. 922 * Caller should execute tmpfs_update on vp after a successful execution. 923 * The vnode must be locked on entry and remain locked on exit. 924 */ 925 int 926 tmpfs_chflags(struct vnode *vp, int flags, kauth_cred_t cred, struct lwp *l) 927 { 928 int error; 929 struct tmpfs_node *node; 930 kauth_action_t action = KAUTH_VNODE_WRITE_FLAGS; 931 int fs_decision = 0; 932 933 KASSERT(VOP_ISLOCKED(vp)); 934 935 node = VP_TO_TMPFS_NODE(vp); 936 937 /* Disallow this operation if the file system is mounted read-only. */ 938 if (vp->v_mount->mnt_flag & MNT_RDONLY) 939 return EROFS; 940 941 if (kauth_cred_geteuid(cred) != node->tn_uid) 942 fs_decision = EACCES; 943 944 /* 945 * If the new flags have non-user flags that are different than 946 * those on the node, we need special permission to change them. 947 */ 948 if ((flags & SF_SETTABLE) != (node->tn_flags & SF_SETTABLE)) { 949 action |= KAUTH_VNODE_WRITE_SYSFLAGS; 950 if (!fs_decision) 951 fs_decision = EPERM; 952 } 953 954 /* 955 * Indicate that this node's flags have system attributes in them if 956 * that's the case. 957 */ 958 if (node->tn_flags & (SF_IMMUTABLE | SF_APPEND)) { 959 action |= KAUTH_VNODE_HAS_SYSFLAGS; 960 } 961 962 error = kauth_authorize_vnode(cred, action, vp, NULL, fs_decision); 963 if (error) 964 return error; 965 966 /* 967 * Set the flags. If we're not setting non-user flags, be careful not 968 * to overwrite them. 969 * 970 * XXX: Can't we always assign here? if the system flags are different, 971 * the code above should catch attempts to change them without 972 * proper permissions, and if we're here it means it's okay to 973 * change them... 974 */ 975 if (action & KAUTH_VNODE_WRITE_SYSFLAGS) { 976 node->tn_flags = flags; 977 } else { 978 /* Clear all user-settable flags and re-set them. */ 979 node->tn_flags &= SF_SETTABLE; 980 node->tn_flags |= (flags & UF_SETTABLE); 981 } 982 983 node->tn_status |= TMPFS_NODE_CHANGED; 984 VN_KNOTE(vp, NOTE_ATTRIB); 985 986 KASSERT(VOP_ISLOCKED(vp)); 987 988 return 0; 989 } 990 991 /* --------------------------------------------------------------------- */ 992 993 /* 994 * Change access mode on the given vnode. 995 * Caller should execute tmpfs_update on vp after a successful execution. 996 * The vnode must be locked on entry and remain locked on exit. 997 */ 998 int 999 tmpfs_chmod(struct vnode *vp, mode_t mode, kauth_cred_t cred, struct lwp *l) 1000 { 1001 int error; 1002 struct tmpfs_node *node; 1003 1004 KASSERT(VOP_ISLOCKED(vp)); 1005 1006 node = VP_TO_TMPFS_NODE(vp); 1007 1008 /* Disallow this operation if the file system is mounted read-only. */ 1009 if (vp->v_mount->mnt_flag & MNT_RDONLY) 1010 return EROFS; 1011 1012 /* Immutable or append-only files cannot be modified, either. */ 1013 if (node->tn_flags & (IMMUTABLE | APPEND)) 1014 return EPERM; 1015 1016 error = genfs_can_chmod(vp, cred, node->tn_uid, node->tn_gid, 1017 mode); 1018 1019 error = kauth_authorize_vnode(cred, KAUTH_VNODE_WRITE_SECURITY, vp, 1020 NULL, error); 1021 if (error) 1022 return (error); 1023 1024 node->tn_mode = (mode & ALLPERMS); 1025 1026 node->tn_status |= TMPFS_NODE_CHANGED; 1027 VN_KNOTE(vp, NOTE_ATTRIB); 1028 1029 KASSERT(VOP_ISLOCKED(vp)); 1030 1031 return 0; 1032 } 1033 1034 /* --------------------------------------------------------------------- */ 1035 1036 /* 1037 * Change ownership of the given vnode. At least one of uid or gid must 1038 * be different than VNOVAL. If one is set to that value, the attribute 1039 * is unchanged. 1040 * Caller should execute tmpfs_update on vp after a successful execution. 1041 * The vnode must be locked on entry and remain locked on exit. 1042 */ 1043 int 1044 tmpfs_chown(struct vnode *vp, uid_t uid, gid_t gid, kauth_cred_t cred, 1045 struct lwp *l) 1046 { 1047 int error; 1048 struct tmpfs_node *node; 1049 1050 KASSERT(VOP_ISLOCKED(vp)); 1051 1052 node = VP_TO_TMPFS_NODE(vp); 1053 1054 /* Assign default values if they are unknown. */ 1055 KASSERT(uid != VNOVAL || gid != VNOVAL); 1056 if (uid == VNOVAL) 1057 uid = node->tn_uid; 1058 if (gid == VNOVAL) 1059 gid = node->tn_gid; 1060 KASSERT(uid != VNOVAL && gid != VNOVAL); 1061 1062 /* Disallow this operation if the file system is mounted read-only. */ 1063 if (vp->v_mount->mnt_flag & MNT_RDONLY) 1064 return EROFS; 1065 1066 /* Immutable or append-only files cannot be modified, either. */ 1067 if (node->tn_flags & (IMMUTABLE | APPEND)) 1068 return EPERM; 1069 1070 error = genfs_can_chown(vp, cred, node->tn_uid, node->tn_gid, uid, 1071 gid); 1072 1073 error = kauth_authorize_vnode(cred, KAUTH_VNODE_CHANGE_OWNERSHIP, vp, 1074 NULL, error); 1075 if (error) 1076 return (error); 1077 1078 node->tn_uid = uid; 1079 node->tn_gid = gid; 1080 1081 node->tn_status |= TMPFS_NODE_CHANGED; 1082 VN_KNOTE(vp, NOTE_ATTRIB); 1083 1084 KASSERT(VOP_ISLOCKED(vp)); 1085 1086 return 0; 1087 } 1088 1089 /* --------------------------------------------------------------------- */ 1090 1091 /* 1092 * Change size of the given vnode. 1093 * Caller should execute tmpfs_update on vp after a successful execution. 1094 * The vnode must be locked on entry and remain locked on exit. 1095 */ 1096 int 1097 tmpfs_chsize(struct vnode *vp, u_quad_t size, kauth_cred_t cred, 1098 struct lwp *l) 1099 { 1100 int error; 1101 struct tmpfs_node *node; 1102 1103 KASSERT(VOP_ISLOCKED(vp)); 1104 1105 node = VP_TO_TMPFS_NODE(vp); 1106 1107 /* Decide whether this is a valid operation based on the file type. */ 1108 error = 0; 1109 switch (vp->v_type) { 1110 case VDIR: 1111 return EISDIR; 1112 1113 case VREG: 1114 if (vp->v_mount->mnt_flag & MNT_RDONLY) 1115 return EROFS; 1116 break; 1117 1118 case VBLK: 1119 /* FALLTHROUGH */ 1120 case VCHR: 1121 /* FALLTHROUGH */ 1122 case VFIFO: 1123 /* Allow modifications of special files even if in the file 1124 * system is mounted read-only (we are not modifying the 1125 * files themselves, but the objects they represent). */ 1126 return 0; 1127 1128 default: 1129 /* Anything else is unsupported. */ 1130 return EOPNOTSUPP; 1131 } 1132 1133 /* Immutable or append-only files cannot be modified, either. */ 1134 if (node->tn_flags & (IMMUTABLE | APPEND)) 1135 return EPERM; 1136 1137 error = tmpfs_truncate(vp, size); 1138 /* tmpfs_truncate will raise the NOTE_EXTEND and NOTE_ATTRIB kevents 1139 * for us, as will update tn_status; no need to do that here. */ 1140 1141 KASSERT(VOP_ISLOCKED(vp)); 1142 1143 return error; 1144 } 1145 1146 /* --------------------------------------------------------------------- */ 1147 1148 /* 1149 * Change access and modification times of the given vnode. 1150 * Caller should execute tmpfs_update on vp after a successful execution. 1151 * The vnode must be locked on entry and remain locked on exit. 1152 */ 1153 int 1154 tmpfs_chtimes(struct vnode *vp, const struct timespec *atime, 1155 const struct timespec *mtime, const struct timespec *btime, 1156 int vaflags, kauth_cred_t cred, struct lwp *l) 1157 { 1158 int error; 1159 struct tmpfs_node *node; 1160 1161 KASSERT(VOP_ISLOCKED(vp)); 1162 1163 node = VP_TO_TMPFS_NODE(vp); 1164 1165 /* Disallow this operation if the file system is mounted read-only. */ 1166 if (vp->v_mount->mnt_flag & MNT_RDONLY) 1167 return EROFS; 1168 1169 /* Immutable or append-only files cannot be modified, either. */ 1170 if (node->tn_flags & (IMMUTABLE | APPEND)) 1171 return EPERM; 1172 1173 error = genfs_can_chtimes(vp, vaflags, node->tn_uid, cred); 1174 1175 error = kauth_authorize_vnode(cred, KAUTH_VNODE_WRITE_TIMES, vp, NULL, 1176 error); 1177 if (error) 1178 return (error); 1179 1180 if (atime->tv_sec != VNOVAL && atime->tv_nsec != VNOVAL) 1181 node->tn_status |= TMPFS_NODE_ACCESSED; 1182 1183 if (mtime->tv_sec != VNOVAL && mtime->tv_nsec != VNOVAL) 1184 node->tn_status |= TMPFS_NODE_MODIFIED; 1185 1186 if (btime->tv_sec == VNOVAL && btime->tv_nsec == VNOVAL) 1187 btime = NULL; 1188 1189 tmpfs_update(vp, atime, mtime, btime, 0); 1190 VN_KNOTE(vp, NOTE_ATTRIB); 1191 1192 KASSERT(VOP_ISLOCKED(vp)); 1193 1194 return 0; 1195 } 1196 1197 /* --------------------------------------------------------------------- */ 1198 1199 /* Sync timestamps */ 1200 void 1201 tmpfs_itimes(struct vnode *vp, const struct timespec *acc, 1202 const struct timespec *mod, const struct timespec *birth) 1203 { 1204 struct tmpfs_node *node; 1205 struct timespec nowtm; 1206 1207 node = VP_TO_TMPFS_NODE(vp); 1208 1209 if ((node->tn_status & (TMPFS_NODE_ACCESSED | TMPFS_NODE_MODIFIED | 1210 TMPFS_NODE_CHANGED)) == 0) 1211 return; 1212 1213 if (birth != NULL) { 1214 node->tn_birthtime = *birth; 1215 } 1216 vfs_timestamp(&nowtm); 1217 1218 if (node->tn_status & TMPFS_NODE_ACCESSED) { 1219 node->tn_atime = acc ? *acc : nowtm; 1220 } 1221 if (node->tn_status & TMPFS_NODE_MODIFIED) { 1222 node->tn_mtime = mod ? *mod : nowtm; 1223 } 1224 if (node->tn_status & TMPFS_NODE_CHANGED) { 1225 node->tn_ctime = nowtm; 1226 } 1227 1228 node->tn_status &= 1229 ~(TMPFS_NODE_ACCESSED | TMPFS_NODE_MODIFIED | TMPFS_NODE_CHANGED); 1230 } 1231 1232 /* --------------------------------------------------------------------- */ 1233 1234 void 1235 tmpfs_update(struct vnode *vp, const struct timespec *acc, 1236 const struct timespec *mod, const struct timespec *birth, int flags) 1237 { 1238 1239 struct tmpfs_node *node; 1240 1241 KASSERT(VOP_ISLOCKED(vp)); 1242 1243 node = VP_TO_TMPFS_NODE(vp); 1244 1245 #if 0 1246 if (flags & UPDATE_CLOSE) 1247 ; /* XXX Need to do anything special? */ 1248 #endif 1249 1250 tmpfs_itimes(vp, acc, mod, birth); 1251 1252 KASSERT(VOP_ISLOCKED(vp)); 1253 } 1254 1255 /* --------------------------------------------------------------------- */ 1256 1257 int 1258 tmpfs_truncate(struct vnode *vp, off_t length) 1259 { 1260 bool extended; 1261 int error; 1262 struct tmpfs_node *node; 1263 1264 node = VP_TO_TMPFS_NODE(vp); 1265 extended = length > node->tn_size; 1266 1267 if (length < 0) { 1268 error = EINVAL; 1269 goto out; 1270 } 1271 1272 if (node->tn_size == length) { 1273 error = 0; 1274 goto out; 1275 } 1276 1277 error = tmpfs_reg_resize(vp, length); 1278 if (error == 0) 1279 node->tn_status |= TMPFS_NODE_CHANGED | TMPFS_NODE_MODIFIED; 1280 1281 out: 1282 tmpfs_update(vp, NULL, NULL, NULL, 0); 1283 1284 return error; 1285 } 1286
Indexes created Sun Sep 21 16:09:51 GMT 2025