vfs_init.c revision 1.66
1 /* $NetBSD: vfs_init.c,v 1.66 2024/12/07 02:23:09 riastradh Exp $ */ 2 3 /*- 4 * Copyright (c) 1998, 2000, 2008 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility, 9 * NASA Ames Research Center. 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 * Copyright (c) 1989, 1993 35 * The Regents of the University of California. All rights reserved. 36 * 37 * This code is derived from software contributed 38 * to Berkeley by John Heidemann of the UCLA Ficus project. 39 * 40 * Source: * @(#)i405_init.c 2.10 92/04/27 UCLA Ficus project 41 * 42 * Redistribution and use in source and binary forms, with or without 43 * modification, are permitted provided that the following conditions 44 * are met: 45 * 1. Redistributions of source code must retain the above copyright 46 * notice, this list of conditions and the following disclaimer. 47 * 2. Redistributions in binary form must reproduce the above copyright 48 * notice, this list of conditions and the following disclaimer in the 49 * documentation and/or other materials provided with the distribution. 50 * 3. Neither the name of the University nor the names of its contributors 51 * may be used to endorse or promote products derived from this software 52 * without specific prior written permission. 53 * 54 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 55 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 56 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 57 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 58 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 59 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 60 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 61 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 62 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 63 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 64 * SUCH DAMAGE. 65 * 66 * @(#)vfs_init.c 8.5 (Berkeley) 5/11/95 67 */ 68 69 #include <sys/cdefs.h> 70 __KERNEL_RCSID(0, "$NetBSD: vfs_init.c,v 1.66 2024/12/07 02:23:09 riastradh Exp $"); 71 72 #include <sys/param.h> 73 #include <sys/types.h> 74 75 #include <sys/buf.h> 76 #include <sys/dirhash.h> 77 #include <sys/errno.h> 78 #include <sys/kauth.h> 79 #include <sys/kmem.h> 80 #include <sys/module.h> 81 #include <sys/mount.h> 82 #include <sys/namei.h> 83 #include <sys/sdt.h> 84 #include <sys/stat.h> 85 #include <sys/sysctl.h> 86 #include <sys/systm.h> 87 #include <sys/time.h> 88 #include <sys/ucred.h> 89 #include <sys/vnode.h> 90 #include <sys/vnode_impl.h> 91 92 #include <miscfs/deadfs/deadfs.h> 93 #include <miscfs/fifofs/fifo.h> 94 #include <miscfs/specfs/specdev.h> 95 96 /* 97 * Sigh, such primitive tools are these... 98 */ 99 #if 0 100 #define DODEBUG(A) A 101 #else 102 #define DODEBUG(A) __nothing 103 #endif 104 105 SDT_PROVIDER_DEFINE(vfs); 106 107 /* 108 * These vnodeopv_descs are listed here because they are not 109 * associated with any particular file system, and thus cannot 110 * be initialized by vfs_attach(). 111 */ 112 const struct vnodeopv_desc * const vfs_special_vnodeopv_descs[] = { 113 &dead_vnodeop_opv_desc, 114 &fifo_vnodeop_opv_desc, 115 &spec_vnodeop_opv_desc, 116 NULL, 117 }; 118 119 struct vfs_list_head vfs_list = /* vfs list */ 120 LIST_HEAD_INITIALIZER(vfs_list); 121 122 static kauth_listener_t mount_listener; 123 124 /* 125 * This code doesn't work if the defn is **vnodop_defns with cc. 126 * The problem is because of the compiler sometimes putting in an 127 * extra level of indirection for arrays. It's an interesting 128 * "feature" of C. 129 */ 130 typedef int (*PFI)(void *); 131 132 /* 133 * A miscellaneous routine. 134 * A generic "default" routine that just returns an error. 135 */ 136 /*ARGSUSED*/ 137 int 138 vn_default_error(void *v) 139 { 140 141 return EOPNOTSUPP; 142 } 143 144 static struct sysctllog *vfs_sysctllog; 145 146 /* 147 * Top level filesystem related information gathering. 148 */ 149 static void 150 sysctl_vfs_setup(void) 151 { 152 153 sysctl_createv(&vfs_sysctllog, 0, NULL, NULL, 154 CTLFLAG_PERMANENT, 155 CTLTYPE_NODE, "generic", 156 SYSCTL_DESCR("Non-specific vfs related information"), 157 NULL, 0, NULL, 0, 158 CTL_VFS, VFS_GENERIC, CTL_EOL); 159 sysctl_createv(&vfs_sysctllog, 0, NULL, NULL, 160 CTLFLAG_PERMANENT, 161 CTLTYPE_STRING, "fstypes", 162 SYSCTL_DESCR("List of file systems present"), 163 sysctl_vfs_generic_fstypes, 0, NULL, 0, 164 CTL_VFS, VFS_GENERIC, CTL_CREATE, CTL_EOL); 165 sysctl_createv(&vfs_sysctllog, 0, NULL, NULL, 166 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 167 CTLTYPE_INT, "magiclinks", 168 SYSCTL_DESCR("Whether \"magic\" symlinks are expanded"), 169 NULL, 0, &vfs_magiclinks, 0, 170 CTL_VFS, VFS_GENERIC, VFS_MAGICLINKS, CTL_EOL); 171 sysctl_createv(&vfs_sysctllog, 0, NULL, NULL, 172 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 173 CTLTYPE_INT, "timestamp_precision", 174 SYSCTL_DESCR("File timestamp precision"), 175 NULL, 0, &vfs_timestamp_precision, 0, 176 CTL_VFS, VFS_GENERIC, VFS_TIMESTAMP_PRECISION, 177 CTL_EOL); 178 } 179 180 /* 181 * vfs_init.c 182 * 183 * Allocate and fill in operations vectors. 184 * 185 * An undocumented feature of this approach to defining operations is that 186 * there can be multiple entries in vfs_opv_descs for the same operations 187 * vector. This allows third parties to extend the set of operations 188 * supported by another layer in a binary compatibile way. For example, 189 * assume that NFS needed to be modified to support Ficus. NFS has an entry 190 * (probably nfs_vnopdeop_decls) declaring all the operations NFS supports by 191 * default. Ficus could add another entry (ficus_nfs_vnodeop_decl_entensions) 192 * listing those new operations Ficus adds to NFS, all without modifying the 193 * NFS code. (Of couse, the OTW NFS protocol still needs to be munged, but 194 * that is a(whole)nother story.) This is a feature. 195 */ 196 197 /* 198 * Init the vector, if it needs it. 199 * Also handle backwards compatibility. 200 */ 201 static void 202 vfs_opv_init_explicit(const struct vnodeopv_desc *vfs_opv_desc) 203 { 204 int (**opv_desc_vector)(void *); 205 const struct vnodeopv_entry_desc *opve_descp; 206 207 opv_desc_vector = *(vfs_opv_desc->opv_desc_vector_p); 208 209 for (opve_descp = vfs_opv_desc->opv_desc_ops; 210 opve_descp->opve_op; 211 opve_descp++) { 212 /* 213 * Sanity check: is this operation listed 214 * in the list of operations? We check this 215 * by seeing if its offset is zero. Since 216 * the default routine should always be listed 217 * first, it should be the only one with a zero 218 * offset. Any other operation with a zero 219 * offset is probably not listed in 220 * vfs_op_descs, and so is probably an error. 221 * 222 * A panic here means the layer programmer 223 * has committed the all-too common bug 224 * of adding a new operation to the layer's 225 * list of vnode operations but 226 * not adding the operation to the system-wide 227 * list of supported operations. 228 */ 229 if (opve_descp->opve_op->vdesc_offset == 0 && 230 opve_descp->opve_op->vdesc_offset != VOFFSET(vop_default)) 231 { 232 printf("operation %s not listed in %s.\n", 233 opve_descp->opve_op->vdesc_name, "vfs_op_descs"); 234 panic("vfs_opv_init: bad operation"); 235 } 236 237 /* 238 * Fill in this entry. 239 */ 240 opv_desc_vector[opve_descp->opve_op->vdesc_offset] = 241 opve_descp->opve_impl; 242 } 243 } 244 245 static void 246 vfs_opv_init_default(const struct vnodeopv_desc *vfs_opv_desc) 247 { 248 int j; 249 int (**opv_desc_vector)(void *); 250 251 opv_desc_vector = *(vfs_opv_desc->opv_desc_vector_p); 252 253 /* 254 * Force every operations vector to have a default routine. 255 */ 256 if (opv_desc_vector[VOFFSET(vop_default)] == NULL) 257 panic("vfs_opv_init: operation vector without vop_default"); 258 259 for (j = 0; j < VNODE_OPS_COUNT; j++) { 260 if (opv_desc_vector[j] == NULL) { 261 opv_desc_vector[j] = 262 opv_desc_vector[VOFFSET(vop_default)]; 263 } 264 } 265 } 266 267 void 268 vfs_opv_init(const struct vnodeopv_desc * const *vopvdpp) 269 { 270 int (**opv_desc_vector)(void *); 271 int i; 272 273 /* 274 * Allocate the vectors. 275 */ 276 for (i = 0; vopvdpp[i] != NULL; i++) { 277 opv_desc_vector = 278 kmem_alloc(VNODE_OPS_COUNT * sizeof(PFI), KM_SLEEP); 279 memset(opv_desc_vector, 0, VNODE_OPS_COUNT * sizeof(PFI)); 280 *(vopvdpp[i]->opv_desc_vector_p) = opv_desc_vector; 281 DODEBUG(printf("vector at %p allocated\n", 282 opv_desc_vector_p)); 283 } 284 285 /* 286 * ...and fill them in. 287 */ 288 for (i = 0; vopvdpp[i] != NULL; i++) 289 vfs_opv_init_explicit(vopvdpp[i]); 290 291 /* 292 * Finally, go back and replace unfilled routines 293 * with their default. 294 */ 295 for (i = 0; vopvdpp[i] != NULL; i++) 296 vfs_opv_init_default(vopvdpp[i]); 297 } 298 299 void 300 vfs_opv_free(const struct vnodeopv_desc * const *vopvdpp) 301 { 302 int i; 303 304 /* 305 * Free the vectors allocated in vfs_opv_init(). 306 */ 307 for (i = 0; vopvdpp[i] != NULL; i++) { 308 kmem_free(*(vopvdpp[i]->opv_desc_vector_p), 309 VNODE_OPS_COUNT * sizeof(PFI)); 310 *(vopvdpp[i]->opv_desc_vector_p) = NULL; 311 } 312 } 313 314 #ifdef DEBUG 315 static void 316 vfs_op_check(void) 317 { 318 int i; 319 320 DODEBUG(printf("Vnode_interface_init.\n")); 321 322 /* 323 * Check offset of each op. 324 */ 325 for (i = 0; vfs_op_descs[i]; i++) { 326 if (vfs_op_descs[i]->vdesc_offset != i) 327 panic("vfs_op_check: vfs_op_desc[] offset mismatch"); 328 } 329 330 if (i != VNODE_OPS_COUNT) { 331 panic("vfs_op_check: vnode ops count mismatch (%d != %d)", 332 i, VNODE_OPS_COUNT); 333 } 334 335 DODEBUG(printf ("vfs_opv_numops=%d\n", VNODE_OPS_COUNT)); 336 } 337 #endif /* DEBUG */ 338 339 /* 340 * Common routine to check if an unprivileged mount is allowed. 341 * 342 * We export just this part (i.e., without the access control) so that if a 343 * secmodel wants to implement finer grained user mounts it can do so without 344 * copying too much code. More elaborate policies (i.e., specific users allowed 345 * to also create devices and/or introduce set-id binaries, or export 346 * file-systems) will require a different implementation. 347 * 348 * This routine is intended to be called from listener context, and as such 349 * does not take credentials as an argument. 350 */ 351 int 352 usermount_common_policy(struct mount *mp, u_long flags) 353 { 354 355 /* No exporting if unprivileged. */ 356 if (flags & MNT_EXPORTED) 357 return EPERM; 358 359 /* Must have 'nosuid' and 'nodev'. */ 360 if ((flags & MNT_NODEV) == 0 || (flags & MNT_NOSUID) == 0) 361 return EPERM; 362 363 /* Retain 'noexec'. */ 364 if ((mp->mnt_flag & MNT_NOEXEC) && (flags & MNT_NOEXEC) == 0) 365 return EPERM; 366 367 return 0; 368 } 369 370 static int 371 mount_listener_cb(kauth_cred_t cred, kauth_action_t action, void *cookie, 372 void *arg0, void *arg1, void *arg2, void *arg3) 373 { 374 int result; 375 enum kauth_system_req req; 376 377 result = KAUTH_RESULT_DEFER; 378 req = (enum kauth_system_req)(uintptr_t)(uintptr_t)arg0; 379 380 if (action != KAUTH_SYSTEM_MOUNT) 381 return result; 382 383 if (req == KAUTH_REQ_SYSTEM_MOUNT_GET) 384 result = KAUTH_RESULT_ALLOW; 385 else if (req == KAUTH_REQ_SYSTEM_MOUNT_DEVICE) { 386 vnode_t *devvp = arg2; 387 accmode_t accmode = (accmode_t)(unsigned long)arg3; 388 int error; 389 390 error = VOP_ACCESS(devvp, accmode, cred); 391 if (!error) 392 result = KAUTH_RESULT_ALLOW; 393 } 394 395 return result; 396 } 397 398 /* 399 * Initialize the vnode structures and initialize each file system type. 400 */ 401 void 402 vfsinit(void) 403 { 404 405 /* 406 * Attach sysctl nodes 407 */ 408 sysctl_vfs_setup(); 409 410 /* 411 * Initialize the vnode table 412 */ 413 vntblinit(); 414 415 /* 416 * Initialize the vnode name cache 417 */ 418 nchinit(); 419 420 #ifdef DEBUG 421 /* 422 * Check the list of vnode operations. 423 */ 424 vfs_op_check(); 425 #endif 426 427 /* 428 * Initialize the special vnode operations. 429 */ 430 vfs_opv_init(vfs_special_vnodeopv_descs); 431 432 /* 433 * Initialise generic dirhash. 434 */ 435 dirhash_init(); 436 437 /* 438 * Initialise VFS hooks. 439 */ 440 vfs_hooks_init(); 441 442 mount_listener = kauth_listen_scope(KAUTH_SCOPE_SYSTEM, 443 mount_listener_cb, NULL); 444 445 /* 446 * Establish each file system which was statically 447 * included in the kernel. 448 */ 449 module_init_class(MODULE_CLASS_VFS); 450 451 /* 452 * Initialize EVFILT_FS for kqueue. 453 */ 454 vfs_evfilt_fs_init(); 455 } 456 457 /* 458 * Drop a reference to a file system type. 459 */ 460 void 461 vfs_delref(struct vfsops *vfs) 462 { 463 464 mutex_enter(&vfs_list_lock); 465 vfs->vfs_refcount--; 466 mutex_exit(&vfs_list_lock); 467 } 468 469 /* 470 * Establish a file system and initialize it. 471 */ 472 int 473 vfs_attach(struct vfsops *vfs) 474 { 475 struct vfsops *v; 476 int error = 0; 477 478 mutex_enter(&vfs_list_lock); 479 480 /* 481 * Make sure this file system doesn't already exist. 482 */ 483 LIST_FOREACH(v, &vfs_list, vfs_list) { 484 if (strcmp(vfs->vfs_name, v->vfs_name) == 0) { 485 error = EEXIST; 486 goto out; 487 } 488 } 489 490 /* 491 * Initialize the vnode operations for this file system. 492 */ 493 vfs_opv_init(vfs->vfs_opv_descs); 494 495 /* 496 * Now initialize the file system itself. 497 */ 498 (*vfs->vfs_init)(); 499 500 /* 501 * ...and link it into the kernel's list. 502 */ 503 LIST_INSERT_HEAD(&vfs_list, vfs, vfs_list); 504 505 /* 506 * Sanity: make sure the reference count is 0. 507 */ 508 vfs->vfs_refcount = 0; 509 out: 510 mutex_exit(&vfs_list_lock); 511 return error; 512 } 513 514 /* 515 * Remove a file system from the kernel. 516 */ 517 int 518 vfs_detach(struct vfsops *vfs) 519 { 520 struct vfsops *v; 521 int error = 0; 522 523 mutex_enter(&vfs_list_lock); 524 525 /* 526 * Make sure no one is using the filesystem. 527 */ 528 if (vfs->vfs_refcount != 0) { 529 error = EBUSY; 530 goto out; 531 } 532 533 /* 534 * ...and remove it from the kernel's list. 535 */ 536 LIST_FOREACH(v, &vfs_list, vfs_list) { 537 if (v == vfs) { 538 LIST_REMOVE(v, vfs_list); 539 break; 540 } 541 } 542 543 if (v == NULL) { 544 error = ESRCH; 545 goto out; 546 } 547 548 /* 549 * Now run the file system-specific cleanups. 550 */ 551 (*vfs->vfs_done)(); 552 553 /* 554 * Free the vnode operations vector. 555 */ 556 vfs_opv_free(vfs->vfs_opv_descs); 557 out: 558 mutex_exit(&vfs_list_lock); 559 return error; 560 } 561 562 void 563 vfs_reinit(void) 564 { 565 struct vfsops *vfs; 566 567 mutex_enter(&vfs_list_lock); 568 LIST_FOREACH(vfs, &vfs_list, vfs_list) { 569 if (vfs->vfs_reinit) { 570 vfs->vfs_refcount++; 571 mutex_exit(&vfs_list_lock); 572 (*vfs->vfs_reinit)(); 573 mutex_enter(&vfs_list_lock); 574 vfs->vfs_refcount--; 575 } 576 } 577 mutex_exit(&vfs_list_lock); 578 } 579
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