1 /*- 2 * Copyright (c) 2001 Dag-Erling Co�dan Sm�rgrav 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer 10 * in this position and unchanged. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. The name of the author may not be used to endorse or promote products 15 * derived from this software without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include "opt_pseudofs.h" 33 34 #include <sys/param.h> 35 #include <sys/kernel.h> 36 #include <sys/systm.h> 37 #include <sys/lock.h> 38 #include <sys/malloc.h> 39 #include <sys/module.h> 40 #include <sys/mount.h> 41 #include <sys/mutex.h> 42 #include <sys/proc.h> 43 #include <sys/sbuf.h> 44 #include <sys/sysctl.h> 45 #include <sys/vnode.h> 46 47 #include <fs/pseudofs/pseudofs.h> 48 #include <fs/pseudofs/pseudofs_internal.h> 49 50 static MALLOC_DEFINE(M_PFSNODES, "pfs_nodes", "pseudofs nodes"); 51 52 SYSCTL_NODE(_vfs, OID_AUTO, pfs, CTLFLAG_RW, 0, 53 "pseudofs"); 54 55 int pfs_trace; 56 SYSCTL_INT(_vfs_pfs, OID_AUTO, trace, CTLFLAG_RW, &pfs_trace, 0, 57 "enable tracing of pseudofs vnode operations"); 58 59 #if PFS_FSNAMELEN != MFSNAMELEN 60 #error "PFS_FSNAMELEN is not equal to MFSNAMELEN" 61 #endif 62 63 /* 64 * Allocate and initialize a node 65 */ 66 static struct pfs_node * 67 pfs_alloc_node(struct pfs_info *pi, const char *name, pfs_type_t type) 68 { 69 struct pfs_node *pn; 70 71 KASSERT(strlen(name) < PFS_NAMELEN, 72 ("%s(): node name is too long", __func__)); 73 74 MALLOC(pn, struct pfs_node *, sizeof *pn, 75 M_PFSNODES, M_WAITOK|M_ZERO); 76 mtx_init(&pn->pn_mutex, "pfs_node", NULL, MTX_DEF | MTX_DUPOK); 77 strlcpy(pn->pn_name, name, sizeof pn->pn_name); 78 pn->pn_type = type; 79 pn->pn_info = pi; 80 return (pn); 81 } 82 83 /* 84 * Add a node to a directory 85 */ 86 static void 87 pfs_add_node(struct pfs_node *parent, struct pfs_node *pn) 88 { 89 #ifdef INVARIANTS 90 struct pfs_node *iter; 91 #endif 92 93 KASSERT(parent != NULL, 94 ("%s(): parent is NULL", __func__)); 95 KASSERT(pn->pn_parent == NULL, 96 ("%s(): node already has a parent", __func__)); 97 KASSERT(parent->pn_info != NULL, 98 ("%s(): parent has no pn_info", __func__)); 99 KASSERT(parent->pn_type == pfstype_dir || 100 parent->pn_type == pfstype_procdir || 101 parent->pn_type == pfstype_root, 102 ("%s(): parent is not a directory", __func__)); 103 104 #ifdef INVARIANTS 105 /* XXX no locking! */ 106 if (pn->pn_type == pfstype_procdir) 107 for (iter = parent; iter != NULL; iter = iter->pn_parent) 108 KASSERT(iter->pn_type != pfstype_procdir, 109 ("%s(): nested process directories", __func__)); 110 for (iter = parent->pn_nodes; iter != NULL; iter = iter->pn_next) { 111 KASSERT(strcmp(pn->pn_name, iter->pn_name) != 0, 112 ("%s(): homonymous siblings", __func__)); 113 if (pn->pn_type == pfstype_procdir) 114 KASSERT(iter->pn_type != pfstype_procdir, 115 ("%s(): sibling process directories", __func__)); 116 } 117 #endif 118 119 pn->pn_parent = parent; 120 pfs_fileno_alloc(pn); 121 122 pfs_lock(parent); 123 pn->pn_next = parent->pn_nodes; 124 if ((parent->pn_flags & PFS_PROCDEP) != 0) 125 pn->pn_flags |= PFS_PROCDEP; 126 parent->pn_nodes = pn; 127 pfs_unlock(parent); 128 } 129 130 /* 131 * Detach a node from its aprent 132 */ 133 static void 134 pfs_detach_node(struct pfs_node *pn) 135 { 136 struct pfs_node *parent = pn->pn_parent; 137 struct pfs_node **iter; 138 139 KASSERT(parent != NULL, ("%s(): node has no parent", __func__)); 140 KASSERT(parent->pn_info == pn->pn_info, 141 ("%s(): parent has different pn_info", __func__)); 142 143 pfs_lock(parent); 144 iter = &parent->pn_nodes; 145 while (*iter != NULL) { 146 if (*iter == pn) { 147 *iter = pn->pn_next; 148 break; 149 } 150 iter = &(*iter)->pn_next; 151 } 152 pn->pn_parent = NULL; 153 pfs_unlock(parent); 154 } 155 156 /* 157 * Add . and .. to a directory 158 */ 159 static void 160 pfs_fixup_dir(struct pfs_node *parent) 161 { 162 struct pfs_node *pn; 163 164 pn = pfs_alloc_node(parent->pn_info, ".", pfstype_this); 165 pfs_add_node(parent, pn); 166 pn = pfs_alloc_node(parent->pn_info, "..", pfstype_parent); 167 pfs_add_node(parent, pn); 168 } 169 170 /* 171 * Create a directory 172 */ 173 struct pfs_node * 174 pfs_create_dir(struct pfs_node *parent, const char *name, 175 pfs_attr_t attr, pfs_vis_t vis, pfs_destroy_t destroy, 176 int flags) 177 { 178 struct pfs_node *pn; 179 180 pn = pfs_alloc_node(parent->pn_info, name, 181 (flags & PFS_PROCDEP) ? pfstype_procdir : pfstype_dir); 182 pn->pn_attr = attr; 183 pn->pn_vis = vis; 184 pn->pn_destroy = destroy; 185 pn->pn_flags = flags; 186 pfs_add_node(parent, pn); 187 pfs_fixup_dir(pn); 188 189 return (pn); 190 } 191 192 /* 193 * Create a file 194 */ 195 struct pfs_node * 196 pfs_create_file(struct pfs_node *parent, const char *name, pfs_fill_t fill, 197 pfs_attr_t attr, pfs_vis_t vis, pfs_destroy_t destroy, 198 int flags) 199 { 200 struct pfs_node *pn; 201 202 pn = pfs_alloc_node(parent->pn_info, name, pfstype_file); 203 pn->pn_fill = fill; 204 pn->pn_attr = attr; 205 pn->pn_vis = vis; 206 pn->pn_destroy = destroy; 207 pn->pn_flags = flags; 208 pfs_add_node(parent, pn); 209 210 return (pn); 211 } 212 213 /* 214 * Create a symlink 215 */ 216 struct pfs_node * 217 pfs_create_link(struct pfs_node *parent, const char *name, pfs_fill_t fill, 218 pfs_attr_t attr, pfs_vis_t vis, pfs_destroy_t destroy, 219 int flags) 220 { 221 struct pfs_node *pn; 222 223 pn = pfs_alloc_node(parent->pn_info, name, pfstype_symlink); 224 pn->pn_fill = fill; 225 pn->pn_attr = attr; 226 pn->pn_vis = vis; 227 pn->pn_destroy = destroy; 228 pn->pn_flags = flags; 229 pfs_add_node(parent, pn); 230 231 return (pn); 232 } 233 234 /* 235 * Locate a node by name 236 */ 237 struct pfs_node * 238 pfs_find_node(struct pfs_node *parent, const char *name) 239 { 240 struct pfs_node *pn; 241 242 pfs_lock(parent); 243 for (pn = parent->pn_nodes; pn != NULL; pn = pn->pn_next) 244 if (strcmp(pn->pn_name, name) == 0) 245 break; 246 pfs_unlock(parent); 247 return (pn); 248 } 249 250 /* 251 * Destroy a node and all its descendants. If the node to be destroyed 252 * has a parent, the parent's mutex must be held. 253 */ 254 int 255 pfs_destroy(struct pfs_node *pn) 256 { 257 struct pfs_node *iter; 258 259 KASSERT(pn != NULL, 260 ("%s(): node is NULL", __func__)); 261 KASSERT(pn->pn_info != NULL, 262 ("%s(): node has no pn_info", __func__)); 263 264 if (pn->pn_parent) 265 pfs_detach_node(pn); 266 267 /* destroy children */ 268 if (pn->pn_type == pfstype_dir || 269 pn->pn_type == pfstype_procdir || 270 pn->pn_type == pfstype_root) { 271 pfs_lock(pn); 272 while (pn->pn_nodes != NULL) { 273 iter = pn->pn_nodes; 274 pn->pn_nodes = iter->pn_next; 275 iter->pn_parent = NULL; 276 pfs_unlock(pn); 277 pfs_destroy(iter); 278 pfs_lock(pn); 279 } 280 pfs_unlock(pn); 281 } 282 283 /* revoke vnodes and fileno */ 284 pfs_purge(pn); 285 286 /* callback to free any private resources */ 287 if (pn->pn_destroy != NULL) 288 pn_destroy(pn); 289 290 /* destroy the node */ 291 pfs_fileno_free(pn); 292 mtx_destroy(&pn->pn_mutex); 293 FREE(pn, M_PFSNODES); 294 295 return (0); 296 } 297 298 /* 299 * Mount a pseudofs instance 300 */ 301 int 302 pfs_mount(struct pfs_info *pi, struct mount *mp, struct thread *td) 303 { 304 struct statfs *sbp; 305 306 if (mp->mnt_flag & MNT_UPDATE) 307 return (EOPNOTSUPP); 308 309 MNT_ILOCK(mp); 310 mp->mnt_flag |= MNT_LOCAL; 311 mp->mnt_kern_flag |= MNTK_MPSAFE; 312 MNT_IUNLOCK(mp); 313 mp->mnt_data = pi; 314 vfs_getnewfsid(mp); 315 316 sbp = &mp->mnt_stat; 317 vfs_mountedfrom(mp, pi->pi_name); 318 sbp->f_bsize = PAGE_SIZE; 319 sbp->f_iosize = PAGE_SIZE; 320 sbp->f_blocks = 1; 321 sbp->f_bfree = 0; 322 sbp->f_bavail = 0; 323 sbp->f_files = 1; 324 sbp->f_ffree = 0; 325 326 return (0); 327 } 328 329 /* 330 * Compatibility shim for old mount(2) system call 331 */ 332 int 333 pfs_cmount(struct mntarg *ma, void *data, int flags, struct thread *td) 334 { 335 int error; 336 337 error = kernel_mount(ma, flags); 338 return (error); 339 } 340 341 /* 342 * Unmount a pseudofs instance 343 */ 344 int 345 pfs_unmount(struct mount *mp, int mntflags, struct thread *td) 346 { 347 int error; 348 349 error = vflush(mp, 0, (mntflags & MNT_FORCE) ? FORCECLOSE : 0, td); 350 return (error); 351 } 352 353 /* 354 * Return a root vnode 355 */ 356 int 357 pfs_root(struct mount *mp, int flags, struct vnode **vpp, struct thread *td) 358 { 359 struct pfs_info *pi; 360 361 pi = (struct pfs_info *)mp->mnt_data; 362 return (pfs_vncache_alloc(mp, vpp, pi->pi_root, NO_PID)); 363 } 364 365 /* 366 * Return filesystem stats 367 */ 368 int 369 pfs_statfs(struct mount *mp, struct statfs *sbp, struct thread *td) 370 { 371 /* no-op: always called with mp->mnt_stat */ 372 return (0); 373 } 374 375 /* 376 * Initialize a pseudofs instance 377 */ 378 int 379 pfs_init(struct pfs_info *pi, struct vfsconf *vfc) 380 { 381 struct pfs_node *root; 382 int error; 383 384 mtx_assert(&Giant, MA_OWNED); 385 386 pfs_fileno_init(pi); 387 388 /* set up the root diretory */ 389 root = pfs_alloc_node(pi, "/", pfstype_root); 390 pi->pi_root = root; 391 pfs_fileno_alloc(root); 392 pfs_fixup_dir(root); 393 394 /* construct file hierarchy */ 395 error = (pi->pi_init)(pi, vfc); 396 if (error) { 397 pfs_destroy(root); 398 pi->pi_root = NULL; 399 return (error); 400 } 401 402 if (bootverbose) 403 printf("%s registered\n", pi->pi_name); 404 return (0); 405 } 406 407 /* 408 * Destroy a pseudofs instance 409 */ 410 int 411 pfs_uninit(struct pfs_info *pi, struct vfsconf *vfc) 412 { 413 int error; 414 415 mtx_assert(&Giant, MA_OWNED); 416 417 pfs_destroy(pi->pi_root); 418 pi->pi_root = NULL; 419 pfs_fileno_uninit(pi); 420 if (bootverbose) 421 printf("%s unregistered\n", pi->pi_name); 422 error = (pi->pi_uninit)(pi, vfc); 423 return (error); 424 } 425 426 /* 427 * Handle load / unload events 428 */ 429 static int 430 pfs_modevent(module_t mod, int evt, void *arg) 431 { 432 switch (evt) { 433 case MOD_LOAD: 434 pfs_vncache_load(); 435 break; 436 case MOD_UNLOAD: 437 case MOD_SHUTDOWN: 438 pfs_vncache_unload(); 439 break; 440 default: 441 return EOPNOTSUPP; 442 break; 443 } 444 return 0; 445 } 446 447 /* 448 * Module declaration 449 */ 450 static moduledata_t pseudofs_data = { 451 "pseudofs", 452 pfs_modevent, 453 NULL 454 }; 455 DECLARE_MODULE(pseudofs, pseudofs_data, SI_SUB_EXEC, SI_ORDER_FIRST); 456 MODULE_VERSION(pseudofs, 1); 457