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 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/conf.h> 38 #include <sys/dirent.h> 39 #include <sys/kernel.h> 40 #include <sys/lock.h> 41 #include <sys/mac.h> 42 #include <sys/malloc.h> 43 #include <sys/proc.h> 44 #include <sys/sysctl.h> 45 #include <sys/vnode.h> 46 47 #include <machine/atomic.h> 48 49 #include <fs/devfs/devfs.h> 50 51 static dev_t devfs_inot[NDEVFSINO]; 52 static dev_t *devfs_overflow; 53 static int devfs_ref[NDEVFSINO]; 54 static int *devfs_refoverflow; 55 static int devfs_nextino = 3; 56 static int devfs_numino; 57 static int devfs_topino; 58 static int devfs_noverflowwant = NDEVFSOVERFLOW; 59 static int devfs_noverflow; 60 static unsigned devfs_generation; 61 62 static void devfs_attemptoverflow(int insist); 63 static struct devfs_dirent *devfs_find (struct devfs_dirent *dd, const char *name, int namelen); 64 65 SYSCTL_NODE(_vfs, OID_AUTO, devfs, CTLFLAG_RW, 0, "DEVFS filesystem"); 66 SYSCTL_UINT(_vfs_devfs, OID_AUTO, noverflow, CTLFLAG_RW, 67 &devfs_noverflowwant, 0, "Size of DEVFS overflow table"); 68 SYSCTL_UINT(_vfs_devfs, OID_AUTO, generation, CTLFLAG_RD, 69 &devfs_generation, 0, "DEVFS generation number"); 70 SYSCTL_UINT(_vfs_devfs, OID_AUTO, inodes, CTLFLAG_RD, 71 &devfs_numino, 0, "DEVFS inodes"); 72 SYSCTL_UINT(_vfs_devfs, OID_AUTO, topinode, CTLFLAG_RD, 73 &devfs_topino, 0, "DEVFS highest inode#"); 74 75 static int * 76 devfs_itor(int inode) 77 { 78 if (inode < NDEVFSINO) 79 return (&devfs_ref[inode]); 80 else if (inode < NDEVFSINO + devfs_noverflow) 81 return (&devfs_refoverflow[inode - NDEVFSINO]); 82 else 83 panic ("YRK!"); 84 } 85 86 static void 87 devfs_dropref(int inode) 88 { 89 int *ip; 90 91 ip = devfs_itor(inode); 92 atomic_add_int(ip, -1); 93 } 94 95 static int 96 devfs_getref(int inode) 97 { 98 int *ip, i, j; 99 dev_t *dp; 100 101 ip = devfs_itor(inode); 102 dp = devfs_itod(inode); 103 for (;;) { 104 i = *ip; 105 j = i + 1; 106 if (!atomic_cmpset_int(ip, i, j)) 107 continue; 108 if (*dp != NULL) 109 return (1); 110 atomic_add_int(ip, -1); 111 return(0); 112 } 113 } 114 115 struct devfs_dirent ** 116 devfs_itode (struct devfs_mount *dm, int inode) 117 { 118 119 if (inode < NDEVFSINO) 120 return (&dm->dm_dirent[inode]); 121 if (devfs_overflow == NULL) 122 return (NULL); 123 if (inode < NDEVFSINO + devfs_noverflow) 124 return (&dm->dm_overflow[inode - NDEVFSINO]); 125 return (NULL); 126 } 127 128 dev_t * 129 devfs_itod (int inode) 130 { 131 132 if (inode < NDEVFSINO) 133 return (&devfs_inot[inode]); 134 if (devfs_overflow == NULL) 135 return (NULL); 136 if (inode < NDEVFSINO + devfs_noverflow) 137 return (&devfs_overflow[inode - NDEVFSINO]); 138 return (NULL); 139 } 140 141 static void 142 devfs_attemptoverflow(int insist) 143 { 144 dev_t **ot; 145 int *or; 146 int n, nb; 147 148 /* Check if somebody beat us to it */ 149 if (devfs_overflow != NULL) 150 return; 151 ot = NULL; 152 or = NULL; 153 n = devfs_noverflowwant; 154 nb = sizeof (dev_t *) * n; 155 MALLOC(ot, dev_t **, nb, M_DEVFS, (insist ? M_WAITOK : M_NOWAIT) | M_ZERO); 156 if (ot == NULL) 157 goto bail; 158 nb = sizeof (int) * n; 159 MALLOC(or, int *, nb, M_DEVFS, (insist ? M_WAITOK : M_NOWAIT) | M_ZERO); 160 if (or == NULL) 161 goto bail; 162 if (!atomic_cmpset_ptr(&devfs_overflow, NULL, ot)) 163 goto bail; 164 devfs_refoverflow = or; 165 devfs_noverflow = n; 166 printf("DEVFS Overflow table with %d entries allocated when %d in use\n", n, devfs_numino); 167 return; 168 169 bail: 170 /* Somebody beat us to it, or something went wrong. */ 171 if (ot != NULL) 172 FREE(ot, M_DEVFS); 173 if (or != NULL) 174 FREE(or, M_DEVFS); 175 return; 176 } 177 178 static struct devfs_dirent * 179 devfs_find(struct devfs_dirent *dd, const char *name, int namelen) 180 { 181 struct devfs_dirent *de; 182 183 TAILQ_FOREACH(de, &dd->de_dlist, de_list) { 184 if (namelen != de->de_dirent->d_namlen) 185 continue; 186 if (bcmp(name, de->de_dirent->d_name, namelen) != 0) 187 continue; 188 break; 189 } 190 return (de); 191 } 192 193 struct devfs_dirent * 194 devfs_newdirent(char *name, int namelen) 195 { 196 int i; 197 struct devfs_dirent *de; 198 struct dirent d; 199 200 d.d_namlen = namelen; 201 i = sizeof (*de) + GENERIC_DIRSIZ(&d); 202 MALLOC(de, struct devfs_dirent *, i, M_DEVFS, M_WAITOK | M_ZERO); 203 de->de_dirent = (struct dirent *)(de + 1); 204 de->de_dirent->d_namlen = namelen; 205 de->de_dirent->d_reclen = GENERIC_DIRSIZ(&d); 206 bcopy(name, de->de_dirent->d_name, namelen); 207 de->de_dirent->d_name[namelen] = '\0'; 208 vfs_timestamp(&de->de_ctime); 209 de->de_mtime = de->de_atime = de->de_ctime; 210 de->de_links = 1; 211 #ifdef MAC 212 mac_init_devfsdirent(de); 213 #endif 214 return (de); 215 } 216 217 struct devfs_dirent * 218 devfs_vmkdir(char *name, int namelen, struct devfs_dirent *dotdot) 219 { 220 struct devfs_dirent *dd; 221 struct devfs_dirent *de; 222 223 dd = devfs_newdirent(name, namelen); 224 225 TAILQ_INIT(&dd->de_dlist); 226 227 dd->de_dirent->d_type = DT_DIR; 228 dd->de_mode = 0555; 229 dd->de_links = 2; 230 dd->de_dir = dd; 231 232 de = devfs_newdirent(".", 1); 233 de->de_dirent->d_type = DT_DIR; 234 de->de_dir = dd; 235 de->de_flags |= DE_DOT; 236 TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list); 237 238 de = devfs_newdirent("..", 2); 239 de->de_dirent->d_type = DT_DIR; 240 if (dotdot == NULL) 241 de->de_dir = dd; 242 else 243 de->de_dir = dotdot; 244 de->de_flags |= DE_DOTDOT; 245 TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list); 246 247 return (dd); 248 } 249 250 static void 251 devfs_delete(struct devfs_dirent *dd, struct devfs_dirent *de) 252 { 253 254 if (de->de_symlink) { 255 FREE(de->de_symlink, M_DEVFS); 256 de->de_symlink = NULL; 257 } 258 if (de->de_vnode) 259 de->de_vnode->v_data = NULL; 260 TAILQ_REMOVE(&dd->de_dlist, de, de_list); 261 #ifdef MAC 262 mac_destroy_devfsdirent(de); 263 #endif 264 FREE(de, M_DEVFS); 265 } 266 267 void 268 devfs_purge(struct devfs_dirent *dd) 269 { 270 struct devfs_dirent *de; 271 272 for (;;) { 273 de = TAILQ_FIRST(&dd->de_dlist); 274 if (de == NULL) 275 break; 276 devfs_delete(dd, de); 277 } 278 FREE(dd, M_DEVFS); 279 } 280 281 282 int 283 devfs_populate(struct devfs_mount *dm) 284 { 285 int i, j; 286 dev_t dev, pdev; 287 struct devfs_dirent *dd; 288 struct devfs_dirent *de, **dep; 289 char *q, *s; 290 291 if (dm->dm_generation == devfs_generation) 292 return (0); 293 lockmgr(&dm->dm_lock, LK_UPGRADE, 0, curthread); 294 if (devfs_noverflow && dm->dm_overflow == NULL) { 295 i = devfs_noverflow * sizeof (struct devfs_dirent *); 296 MALLOC(dm->dm_overflow, struct devfs_dirent **, i, 297 M_DEVFS, M_WAITOK | M_ZERO); 298 } 299 while (dm->dm_generation != devfs_generation) { 300 dm->dm_generation = devfs_generation; 301 for (i = 0; i <= devfs_topino; i++) { 302 dev = *devfs_itod(i); 303 dep = devfs_itode(dm, i); 304 de = *dep; 305 if (dev == NULL && de == DE_DELETED) { 306 *dep = NULL; 307 continue; 308 } 309 if (dev == NULL && de != NULL) { 310 dd = de->de_dir; 311 *dep = NULL; 312 TAILQ_REMOVE(&dd->de_dlist, de, de_list); 313 if (de->de_vnode) 314 de->de_vnode->v_data = NULL; 315 FREE(de, M_DEVFS); 316 devfs_dropref(i); 317 continue; 318 } 319 if (dev == NULL) 320 continue; 321 if (de != NULL) 322 continue; 323 if (!devfs_getref(i)) 324 continue; 325 dd = dm->dm_basedir; 326 s = dev->si_name; 327 for (;;) { 328 for (q = s; *q != '/' && *q != '\0'; q++) 329 continue; 330 if (*q != '/') 331 break; 332 de = devfs_find(dd, s, q - s); 333 if (de == NULL) { 334 de = devfs_vmkdir(s, q - s, dd); 335 #ifdef MAC 336 mac_create_devfs_directory( 337 dm->dm_mount, s, q - s, de); 338 #endif 339 de->de_inode = dm->dm_inode++; 340 TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list); 341 dd->de_links++; 342 } 343 s = q + 1; 344 dd = de; 345 } 346 de = devfs_newdirent(s, q - s); 347 if (dev->si_flags & SI_ALIAS) { 348 de->de_inode = dm->dm_inode++; 349 de->de_uid = 0; 350 de->de_gid = 0; 351 de->de_mode = 0755; 352 de->de_dirent->d_type = DT_LNK; 353 pdev = dev->si_parent; 354 j = strlen(pdev->si_name) + 1; 355 MALLOC(de->de_symlink, char *, j, M_DEVFS, M_WAITOK); 356 bcopy(pdev->si_name, de->de_symlink, j); 357 } else { 358 de->de_inode = i; 359 de->de_uid = dev->si_uid; 360 de->de_gid = dev->si_gid; 361 de->de_mode = dev->si_mode; 362 de->de_dirent->d_type = DT_CHR; 363 } 364 #ifdef MAC 365 mac_create_devfs_device(dm->dm_mount, dev, de); 366 #endif 367 *dep = de; 368 de->de_dir = dd; 369 devfs_rules_apply(dm, de); 370 TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list); 371 #if 0 372 printf("Add ino%d %s\n", i, dev->si_name); 373 #endif 374 } 375 } 376 lockmgr(&dm->dm_lock, LK_DOWNGRADE, 0, curthread); 377 return (0); 378 } 379 380 void 381 devfs_create(dev_t dev) 382 { 383 int ino, i, *ip; 384 dev_t *dp; 385 386 for (;;) { 387 /* Grab the next inode number */ 388 ino = devfs_nextino; 389 i = ino + 1; 390 /* wrap around when we reach the end */ 391 if (i >= NDEVFSINO + devfs_noverflow) 392 i = 3; 393 if (!atomic_cmpset_int(&devfs_nextino, ino, i)) 394 continue; 395 396 /* see if it was occupied */ 397 dp = devfs_itod(ino); 398 if (dp == NULL) 399 Debugger("dp == NULL\n"); 400 if (*dp != NULL) 401 continue; 402 ip = devfs_itor(ino); 403 if (ip == NULL) 404 Debugger("ip == NULL\n"); 405 if (*ip != 0) 406 continue; 407 408 if (!atomic_cmpset_ptr(dp, NULL, dev)) 409 continue; 410 411 dev->si_inode = ino; 412 for (;;) { 413 i = devfs_topino; 414 if (i >= ino) 415 break; 416 if (atomic_cmpset_int(&devfs_topino, i, ino)) 417 break; 418 printf("failed topino %d %d\n", i, ino); 419 } 420 break; 421 } 422 423 atomic_add_int(&devfs_numino, 1); 424 atomic_add_int(&devfs_generation, 1); 425 if (devfs_overflow == NULL && devfs_numino + 100 > NDEVFSINO) 426 devfs_attemptoverflow(0); 427 } 428 429 void 430 devfs_destroy(dev_t dev) 431 { 432 int ino, i; 433 434 ino = dev->si_inode; 435 dev->si_inode = 0; 436 if (ino == 0) 437 return; 438 if (atomic_cmpset_ptr(devfs_itod(ino), dev, NULL)) { 439 atomic_add_int(&devfs_generation, 1); 440 atomic_add_int(&devfs_numino, -1); 441 i = devfs_nextino; 442 if (ino < i) 443 atomic_cmpset_int(&devfs_nextino, i, ino); 444 } 445 } 446 447 static void 448 devfs_init(void *junk) 449 { 450 451 devfs_rules_init(); 452 } 453 454 SYSINIT(devfs, SI_SUB_DEVFS, SI_ORDER_FIRST, devfs_init, NULL); 455 456