1 #define DEBUG 1 2 /* 3 * Copyright (c) 2000 4 * Poul-Henning Kamp. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Neither the name of the University nor the names of its contributors 12 * may be used to endorse or promote products derived from this software 13 * without specific prior written permission. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 * 27 * From: FreeBSD: src/sys/miscfs/kernfs/kernfs_vfsops.c 1.36 28 * 29 * $FreeBSD$ 30 */ 31 32 #include "opt_devfs.h" 33 #include "opt_mac.h" 34 #ifndef NODEVFS 35 36 #include <sys/param.h> 37 #include <sys/systm.h> 38 #include <sys/conf.h> 39 #include <sys/dirent.h> 40 #include <sys/kernel.h> 41 #include <sys/lock.h> 42 #include <sys/mac.h> 43 #include <sys/malloc.h> 44 #include <sys/proc.h> 45 #include <sys/sysctl.h> 46 #include <sys/vnode.h> 47 48 #include <machine/atomic.h> 49 50 #include <fs/devfs/devfs.h> 51 52 static dev_t devfs_inot[NDEVFSINO]; 53 static dev_t *devfs_overflow; 54 static int devfs_ref[NDEVFSINO]; 55 static int *devfs_refoverflow; 56 static int devfs_nextino = 3; 57 static int devfs_numino; 58 static int devfs_topino; 59 static int devfs_noverflowwant = NDEVFSOVERFLOW; 60 static int devfs_noverflow; 61 static unsigned devfs_generation; 62 63 static void devfs_attemptoverflow(int insist); 64 static struct devfs_dirent *devfs_find (struct devfs_dirent *dd, const char *name, int namelen); 65 66 SYSCTL_NODE(_vfs, OID_AUTO, devfs, CTLFLAG_RW, 0, "DEVFS filesystem"); 67 SYSCTL_UINT(_vfs_devfs, OID_AUTO, noverflow, CTLFLAG_RW, 68 &devfs_noverflowwant, 0, "Size of DEVFS overflow table"); 69 SYSCTL_UINT(_vfs_devfs, OID_AUTO, generation, CTLFLAG_RD, 70 &devfs_generation, 0, "DEVFS generation number"); 71 SYSCTL_UINT(_vfs_devfs, OID_AUTO, inodes, CTLFLAG_RD, 72 &devfs_numino, 0, "DEVFS inodes"); 73 SYSCTL_UINT(_vfs_devfs, OID_AUTO, topinode, CTLFLAG_RD, 74 &devfs_topino, 0, "DEVFS highest inode#"); 75 76 static int * 77 devfs_itor(int inode) 78 { 79 if (inode < NDEVFSINO) 80 return (&devfs_ref[inode]); 81 else if (inode < NDEVFSINO + devfs_noverflow) 82 return (&devfs_refoverflow[inode - NDEVFSINO]); 83 else 84 panic ("YRK!"); 85 } 86 87 static void 88 devfs_dropref(int inode) 89 { 90 int *ip; 91 92 ip = devfs_itor(inode); 93 atomic_add_int(ip, -1); 94 } 95 96 static int 97 devfs_getref(int inode) 98 { 99 int *ip, i, j; 100 dev_t *dp; 101 102 ip = devfs_itor(inode); 103 dp = devfs_itod(inode); 104 for (;;) { 105 i = *ip; 106 j = i + 1; 107 if (!atomic_cmpset_int(ip, i, j)) 108 continue; 109 if (*dp != NULL) 110 return (1); 111 atomic_add_int(ip, -1); 112 return(0); 113 } 114 } 115 116 struct devfs_dirent ** 117 devfs_itode (struct devfs_mount *dm, int inode) 118 { 119 120 if (inode < NDEVFSINO) 121 return (&dm->dm_dirent[inode]); 122 if (devfs_overflow == NULL) 123 return (NULL); 124 if (inode < NDEVFSINO + devfs_noverflow) 125 return (&dm->dm_overflow[inode - NDEVFSINO]); 126 return (NULL); 127 } 128 129 dev_t * 130 devfs_itod (int inode) 131 { 132 133 if (inode < NDEVFSINO) 134 return (&devfs_inot[inode]); 135 if (devfs_overflow == NULL) 136 return (NULL); 137 if (inode < NDEVFSINO + devfs_noverflow) 138 return (&devfs_overflow[inode - NDEVFSINO]); 139 return (NULL); 140 } 141 142 static void 143 devfs_attemptoverflow(int insist) 144 { 145 dev_t **ot; 146 int *or; 147 int n, nb; 148 149 /* Check if somebody beat us to it */ 150 if (devfs_overflow != NULL) 151 return; 152 ot = NULL; 153 or = NULL; 154 n = devfs_noverflowwant; 155 nb = sizeof (dev_t *) * n; 156 MALLOC(ot, dev_t **, nb, M_DEVFS, (insist ? 0 : M_NOWAIT) | M_ZERO); 157 if (ot == NULL) 158 goto bail; 159 nb = sizeof (int) * n; 160 MALLOC(or, int *, nb, M_DEVFS, (insist ? 0 : M_NOWAIT) | M_ZERO); 161 if (or == NULL) 162 goto bail; 163 if (!atomic_cmpset_ptr(&devfs_overflow, NULL, ot)) 164 goto bail; 165 devfs_refoverflow = or; 166 devfs_noverflow = n; 167 printf("DEVFS Overflow table with %d entries allocated when %d in use\n", n, devfs_numino); 168 return; 169 170 bail: 171 /* Somebody beat us to it, or something went wrong. */ 172 if (ot != NULL) 173 FREE(ot, M_DEVFS); 174 if (or != NULL) 175 FREE(or, M_DEVFS); 176 return; 177 } 178 179 static struct devfs_dirent * 180 devfs_find(struct devfs_dirent *dd, const char *name, int namelen) 181 { 182 struct devfs_dirent *de; 183 184 TAILQ_FOREACH(de, &dd->de_dlist, de_list) { 185 if (namelen != de->de_dirent->d_namlen) 186 continue; 187 if (bcmp(name, de->de_dirent->d_name, namelen) != 0) 188 continue; 189 break; 190 } 191 return (de); 192 } 193 194 struct devfs_dirent * 195 devfs_newdirent(char *name, int namelen) 196 { 197 int i; 198 struct devfs_dirent *de; 199 struct dirent d; 200 201 d.d_namlen = namelen; 202 i = sizeof (*de) + GENERIC_DIRSIZ(&d); 203 MALLOC(de, struct devfs_dirent *, i, M_DEVFS, M_ZERO); 204 de->de_dirent = (struct dirent *)(de + 1); 205 de->de_dirent->d_namlen = namelen; 206 de->de_dirent->d_reclen = GENERIC_DIRSIZ(&d); 207 bcopy(name, de->de_dirent->d_name, namelen); 208 de->de_dirent->d_name[namelen] = '\0'; 209 vfs_timestamp(&de->de_ctime); 210 de->de_mtime = de->de_atime = de->de_ctime; 211 de->de_links = 1; 212 #ifdef MAC 213 mac_init_devfsdirent(de); 214 #endif 215 return (de); 216 } 217 218 struct devfs_dirent * 219 devfs_vmkdir(char *name, int namelen, struct devfs_dirent *dotdot) 220 { 221 struct devfs_dirent *dd; 222 struct devfs_dirent *de; 223 224 dd = devfs_newdirent(name, namelen); 225 226 TAILQ_INIT(&dd->de_dlist); 227 228 dd->de_dirent->d_type = DT_DIR; 229 dd->de_mode = 0555; 230 dd->de_links = 2; 231 dd->de_dir = dd; 232 233 de = devfs_newdirent(".", 1); 234 de->de_dirent->d_type = DT_DIR; 235 de->de_dir = dd; 236 de->de_flags |= DE_DOT; 237 TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list); 238 239 de = devfs_newdirent("..", 2); 240 de->de_dirent->d_type = DT_DIR; 241 if (dotdot == NULL) 242 de->de_dir = dd; 243 else 244 de->de_dir = dotdot; 245 de->de_flags |= DE_DOTDOT; 246 TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list); 247 248 return (dd); 249 } 250 251 static void 252 devfs_delete(struct devfs_dirent *dd, struct devfs_dirent *de) 253 { 254 255 if (de->de_symlink) { 256 FREE(de->de_symlink, M_DEVFS); 257 de->de_symlink = NULL; 258 } 259 if (de->de_vnode) 260 de->de_vnode->v_data = NULL; 261 TAILQ_REMOVE(&dd->de_dlist, de, de_list); 262 #ifdef MAC 263 mac_destroy_devfsdirent(de); 264 #endif 265 FREE(de, M_DEVFS); 266 } 267 268 void 269 devfs_purge(struct devfs_dirent *dd) 270 { 271 struct devfs_dirent *de; 272 273 for (;;) { 274 de = TAILQ_FIRST(&dd->de_dlist); 275 if (de == NULL) 276 break; 277 devfs_delete(dd, de); 278 } 279 FREE(dd, M_DEVFS); 280 } 281 282 283 int 284 devfs_populate(struct devfs_mount *dm) 285 { 286 int i, j; 287 dev_t dev, pdev; 288 struct devfs_dirent *dd; 289 struct devfs_dirent *de, **dep; 290 char *q, *s; 291 292 if (dm->dm_generation == devfs_generation) 293 return (0); 294 lockmgr(&dm->dm_lock, LK_UPGRADE, 0, curthread); 295 if (devfs_noverflow && dm->dm_overflow == NULL) { 296 i = devfs_noverflow * sizeof (struct devfs_dirent *); 297 MALLOC(dm->dm_overflow, struct devfs_dirent **, i, 298 M_DEVFS, M_ZERO); 299 } 300 while (dm->dm_generation != devfs_generation) { 301 dm->dm_generation = devfs_generation; 302 for (i = 0; i <= devfs_topino; i++) { 303 dev = *devfs_itod(i); 304 dep = devfs_itode(dm, i); 305 de = *dep; 306 if (dev == NULL && de == DE_DELETED) { 307 *dep = NULL; 308 continue; 309 } 310 if (dev == NULL && de != NULL) { 311 dd = de->de_dir; 312 *dep = NULL; 313 TAILQ_REMOVE(&dd->de_dlist, de, de_list); 314 if (de->de_vnode) 315 de->de_vnode->v_data = NULL; 316 FREE(de, M_DEVFS); 317 devfs_dropref(i); 318 continue; 319 } 320 if (dev == NULL) 321 continue; 322 if (de != NULL) 323 continue; 324 if (!devfs_getref(i)) 325 continue; 326 dd = dm->dm_basedir; 327 s = dev->si_name; 328 for (;;) { 329 for (q = s; *q != '/' && *q != '\0'; q++) 330 continue; 331 if (*q != '/') 332 break; 333 de = devfs_find(dd, s, q - s); 334 if (de == NULL) { 335 de = devfs_vmkdir(s, q - s, dd); 336 #ifdef MAC 337 mac_create_devfs_directory( 338 dm->dm_mount, s, q - s, de); 339 #endif 340 de->de_inode = dm->dm_inode++; 341 TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list); 342 dd->de_links++; 343 } 344 s = q + 1; 345 dd = de; 346 } 347 de = devfs_newdirent(s, q - s); 348 if (dev->si_flags & SI_ALIAS) { 349 de->de_inode = dm->dm_inode++; 350 de->de_uid = 0; 351 de->de_gid = 0; 352 de->de_mode = 0755; 353 de->de_dirent->d_type = DT_LNK; 354 pdev = dev->si_parent; 355 j = strlen(pdev->si_name) + 1; 356 MALLOC(de->de_symlink, char *, j, M_DEVFS, 0); 357 bcopy(pdev->si_name, de->de_symlink, j); 358 } else { 359 de->de_inode = i; 360 de->de_uid = dev->si_uid; 361 de->de_gid = dev->si_gid; 362 de->de_mode = dev->si_mode; 363 de->de_dirent->d_type = DT_CHR; 364 } 365 #ifdef MAC 366 mac_create_devfs_device(dm->dm_mount, dev, de); 367 #endif 368 *dep = de; 369 de->de_dir = dd; 370 devfs_rules_apply(dm, de); 371 TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list); 372 #if 0 373 printf("Add ino%d %s\n", i, dev->si_name); 374 #endif 375 } 376 } 377 lockmgr(&dm->dm_lock, LK_DOWNGRADE, 0, curthread); 378 return (0); 379 } 380 381 static void 382 devfs_create(dev_t dev) 383 { 384 int ino, i, *ip; 385 dev_t *dp; 386 387 for (;;) { 388 /* Grab the next inode number */ 389 ino = devfs_nextino; 390 i = ino + 1; 391 /* wrap around when we reach the end */ 392 if (i >= NDEVFSINO + devfs_noverflow) 393 i = 3; 394 if (!atomic_cmpset_int(&devfs_nextino, ino, i)) 395 continue; 396 397 /* see if it was occupied */ 398 dp = devfs_itod(ino); 399 if (dp == NULL) 400 Debugger("dp == NULL\n"); 401 if (*dp != NULL) 402 continue; 403 ip = devfs_itor(ino); 404 if (ip == NULL) 405 Debugger("ip == NULL\n"); 406 if (*ip != 0) 407 continue; 408 409 if (!atomic_cmpset_ptr(dp, NULL, dev)) 410 continue; 411 412 dev->si_inode = ino; 413 for (;;) { 414 i = devfs_topino; 415 if (i >= ino) 416 break; 417 if (atomic_cmpset_int(&devfs_topino, i, ino)) 418 break; 419 printf("failed topino %d %d\n", i, ino); 420 } 421 break; 422 } 423 424 atomic_add_int(&devfs_numino, 1); 425 atomic_add_int(&devfs_generation, 1); 426 if (devfs_overflow == NULL && devfs_numino + 100 > NDEVFSINO) 427 devfs_attemptoverflow(0); 428 } 429 430 static void 431 devfs_destroy(dev_t dev) 432 { 433 int ino, i; 434 435 ino = dev->si_inode; 436 dev->si_inode = 0; 437 if (ino == 0) 438 return; 439 if (atomic_cmpset_ptr(devfs_itod(ino), dev, NULL)) { 440 atomic_add_int(&devfs_generation, 1); 441 atomic_add_int(&devfs_numino, -1); 442 i = devfs_nextino; 443 if (ino < i) 444 atomic_cmpset_int(&devfs_nextino, i, ino); 445 } 446 } 447 448 static void 449 devfs_init(void *junk) 450 { 451 devfs_create_hook = devfs_create; 452 devfs_destroy_hook = devfs_destroy; 453 devfs_rules_init(); 454 } 455 456 SYSINIT(devfs, SI_SUB_DEVFS, SI_ORDER_FIRST, devfs_init, NULL); 457 458 #endif 459