1 /*- 2 * Copyright (c) 2000,2004 3 * Poul-Henning Kamp. 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 * 2. Neither the name of the University nor the names of its contributors 11 * may be used to endorse or promote products derived from this software 12 * without specific prior written permission. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * From: FreeBSD: src/sys/miscfs/kernfs/kernfs_vfsops.c 1.36 27 * 28 * $FreeBSD$ 29 */ 30 31 #include "opt_devfs.h" 32 #include "opt_mac.h" 33 34 #include <sys/param.h> 35 #include <sys/systm.h> 36 #include <sys/conf.h> 37 #include <sys/dirent.h> 38 #include <sys/kernel.h> 39 #include <sys/lock.h> 40 #include <sys/mac.h> 41 #include <sys/malloc.h> 42 #include <sys/proc.h> 43 #include <sys/sysctl.h> 44 #include <sys/vnode.h> 45 46 #include <machine/atomic.h> 47 48 #include <fs/devfs/devfs.h> 49 50 static struct cdev *devfs_inot[NDEVFSINO]; 51 static struct cdev **devfs_overflow; 52 static int devfs_ref[NDEVFSINO]; 53 static int *devfs_refoverflow; 54 static int devfs_nextino = 3; 55 static int devfs_numino; 56 static int devfs_topino; 57 static int devfs_noverflowwant = NDEVFSOVERFLOW; 58 static int devfs_noverflow; 59 static unsigned devfs_generation; 60 61 static struct devfs_dirent *devfs_find (struct devfs_dirent *dd, const char *name, int namelen); 62 63 static SYSCTL_NODE(_vfs, OID_AUTO, devfs, CTLFLAG_RW, 0, "DEVFS filesystem"); 64 SYSCTL_UINT(_vfs_devfs, OID_AUTO, noverflow, CTLFLAG_RW, 65 &devfs_noverflowwant, 0, "Size of DEVFS overflow table"); 66 SYSCTL_UINT(_vfs_devfs, OID_AUTO, generation, CTLFLAG_RD, 67 &devfs_generation, 0, "DEVFS generation number"); 68 SYSCTL_UINT(_vfs_devfs, OID_AUTO, inodes, CTLFLAG_RD, 69 &devfs_numino, 0, "DEVFS inodes"); 70 SYSCTL_UINT(_vfs_devfs, OID_AUTO, topinode, CTLFLAG_RD, 71 &devfs_topino, 0, "DEVFS highest inode#"); 72 73 static int * 74 devfs_itor(int inode) 75 { 76 if (inode < NDEVFSINO) 77 return (&devfs_ref[inode]); 78 else if (inode < NDEVFSINO + devfs_noverflow) 79 return (&devfs_refoverflow[inode - NDEVFSINO]); 80 else 81 panic ("YRK!"); 82 } 83 84 static void 85 devfs_dropref(int inode) 86 { 87 int *ip; 88 89 ip = devfs_itor(inode); 90 atomic_add_int(ip, -1); 91 } 92 93 static int 94 devfs_getref(int inode) 95 { 96 int *ip, i, j; 97 struct cdev **dp; 98 99 ip = devfs_itor(inode); 100 dp = devfs_itod(inode); 101 for (;;) { 102 i = *ip; 103 j = i + 1; 104 if (!atomic_cmpset_int(ip, i, j)) 105 continue; 106 if (*dp != NULL) 107 return (1); 108 atomic_add_int(ip, -1); 109 return(0); 110 } 111 } 112 113 struct devfs_dirent ** 114 devfs_itode (struct devfs_mount *dm, int inode) 115 { 116 117 if (inode < NDEVFSINO) 118 return (&dm->dm_dirent[inode]); 119 if (devfs_overflow == NULL) 120 return (NULL); 121 if (inode < NDEVFSINO + devfs_noverflow) 122 return (&dm->dm_overflow[inode - NDEVFSINO]); 123 return (NULL); 124 } 125 126 struct cdev ** 127 devfs_itod (int inode) 128 { 129 130 if (inode < NDEVFSINO) 131 return (&devfs_inot[inode]); 132 if (devfs_overflow == NULL) 133 return (NULL); 134 if (inode < NDEVFSINO + devfs_noverflow) 135 return (&devfs_overflow[inode - NDEVFSINO]); 136 return (NULL); 137 } 138 139 static struct devfs_dirent * 140 devfs_find(struct devfs_dirent *dd, const char *name, int namelen) 141 { 142 struct devfs_dirent *de; 143 144 TAILQ_FOREACH(de, &dd->de_dlist, de_list) { 145 if (namelen != de->de_dirent->d_namlen) 146 continue; 147 if (bcmp(name, de->de_dirent->d_name, namelen) != 0) 148 continue; 149 break; 150 } 151 return (de); 152 } 153 154 struct devfs_dirent * 155 devfs_newdirent(char *name, int namelen) 156 { 157 int i; 158 struct devfs_dirent *de; 159 struct dirent d; 160 161 d.d_namlen = namelen; 162 i = sizeof (*de) + GENERIC_DIRSIZ(&d); 163 MALLOC(de, struct devfs_dirent *, i, M_DEVFS, M_WAITOK | M_ZERO); 164 de->de_dirent = (struct dirent *)(de + 1); 165 de->de_dirent->d_namlen = namelen; 166 de->de_dirent->d_reclen = GENERIC_DIRSIZ(&d); 167 bcopy(name, de->de_dirent->d_name, namelen); 168 de->de_dirent->d_name[namelen] = '\0'; 169 vfs_timestamp(&de->de_ctime); 170 de->de_mtime = de->de_atime = de->de_ctime; 171 de->de_links = 1; 172 #ifdef MAC 173 mac_init_devfsdirent(de); 174 #endif 175 return (de); 176 } 177 178 struct devfs_dirent * 179 devfs_vmkdir(char *name, int namelen, struct devfs_dirent *dotdot) 180 { 181 struct devfs_dirent *dd; 182 struct devfs_dirent *de; 183 184 dd = devfs_newdirent(name, namelen); 185 186 TAILQ_INIT(&dd->de_dlist); 187 188 dd->de_dirent->d_type = DT_DIR; 189 dd->de_mode = 0555; 190 dd->de_links = 2; 191 dd->de_dir = dd; 192 193 de = devfs_newdirent(".", 1); 194 de->de_dirent->d_type = DT_DIR; 195 de->de_dir = dd; 196 de->de_flags |= DE_DOT; 197 TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list); 198 199 de = devfs_newdirent("..", 2); 200 de->de_dirent->d_type = DT_DIR; 201 if (dotdot == NULL) 202 de->de_dir = dd; 203 else 204 de->de_dir = dotdot; 205 de->de_flags |= DE_DOTDOT; 206 TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list); 207 208 return (dd); 209 } 210 211 static void 212 devfs_delete(struct devfs_dirent *dd, struct devfs_dirent *de) 213 { 214 215 if (de->de_symlink) { 216 FREE(de->de_symlink, M_DEVFS); 217 de->de_symlink = NULL; 218 } 219 if (de->de_vnode) 220 de->de_vnode->v_data = NULL; 221 TAILQ_REMOVE(&dd->de_dlist, de, de_list); 222 #ifdef MAC 223 mac_destroy_devfsdirent(de); 224 #endif 225 FREE(de, M_DEVFS); 226 } 227 228 void 229 devfs_purge(struct devfs_dirent *dd) 230 { 231 struct devfs_dirent *de; 232 233 for (;;) { 234 de = TAILQ_FIRST(&dd->de_dlist); 235 if (de == NULL) 236 break; 237 devfs_delete(dd, de); 238 } 239 FREE(dd, M_DEVFS); 240 } 241 242 243 int 244 devfs_populate(struct devfs_mount *dm) 245 { 246 int i, j; 247 struct cdev *dev, *pdev; 248 struct devfs_dirent *dd; 249 struct devfs_dirent *de, **dep; 250 char *q, *s; 251 252 if (dm->dm_generation == devfs_generation) 253 return (0); 254 lockmgr(&dm->dm_lock, LK_UPGRADE, 0, curthread); 255 if (devfs_noverflow && dm->dm_overflow == NULL) { 256 i = devfs_noverflow * sizeof (struct devfs_dirent *); 257 MALLOC(dm->dm_overflow, struct devfs_dirent **, i, 258 M_DEVFS, M_WAITOK | M_ZERO); 259 } 260 while (dm->dm_generation != devfs_generation) { 261 dm->dm_generation = devfs_generation; 262 for (i = 0; i <= devfs_topino; i++) { 263 dev = *devfs_itod(i); 264 dep = devfs_itode(dm, i); 265 de = *dep; 266 if (dev == NULL && de == DE_DELETED) { 267 *dep = NULL; 268 continue; 269 } 270 if (dev == NULL && de != NULL) { 271 dd = de->de_dir; 272 *dep = NULL; 273 TAILQ_REMOVE(&dd->de_dlist, de, de_list); 274 if (de->de_vnode) 275 de->de_vnode->v_data = NULL; 276 FREE(de, M_DEVFS); 277 devfs_dropref(i); 278 continue; 279 } 280 if (dev == NULL) 281 continue; 282 if (de != NULL) 283 continue; 284 if (!devfs_getref(i)) 285 continue; 286 dd = dm->dm_basedir; 287 s = dev->si_name; 288 for (;;) { 289 for (q = s; *q != '/' && *q != '\0'; q++) 290 continue; 291 if (*q != '/') 292 break; 293 de = devfs_find(dd, s, q - s); 294 if (de == NULL) { 295 de = devfs_vmkdir(s, q - s, dd); 296 #ifdef MAC 297 mac_create_devfs_directory( 298 dm->dm_mount, s, q - s, de); 299 #endif 300 de->de_inode = dm->dm_inode++; 301 TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list); 302 dd->de_links++; 303 } 304 s = q + 1; 305 dd = de; 306 } 307 de = devfs_newdirent(s, q - s); 308 if (dev->si_flags & SI_ALIAS) { 309 de->de_inode = dm->dm_inode++; 310 de->de_uid = 0; 311 de->de_gid = 0; 312 de->de_mode = 0755; 313 de->de_dirent->d_type = DT_LNK; 314 pdev = dev->si_parent; 315 j = strlen(pdev->si_name) + 1; 316 MALLOC(de->de_symlink, char *, j, M_DEVFS, M_WAITOK); 317 bcopy(pdev->si_name, de->de_symlink, j); 318 } else { 319 de->de_inode = i; 320 de->de_uid = dev->si_uid; 321 de->de_gid = dev->si_gid; 322 de->de_mode = dev->si_mode; 323 de->de_dirent->d_type = DT_CHR; 324 } 325 #ifdef MAC 326 mac_create_devfs_device(dm->dm_mount, dev, de); 327 #endif 328 *dep = de; 329 de->de_dir = dd; 330 devfs_rules_apply(dm, de); 331 TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list); 332 } 333 } 334 lockmgr(&dm->dm_lock, LK_DOWNGRADE, 0, curthread); 335 return (0); 336 } 337 338 /* 339 * devfs_create() and devfs_destroy() are called from kern_conf.c and 340 * in both cases the devlock() mutex is held, so no further locking 341 * is necesary and no sleeping allowed. 342 */ 343 344 void 345 devfs_create(struct cdev *dev) 346 { 347 int ino, i, *ip; 348 struct cdev **dp; 349 struct cdev **ot; 350 int *or; 351 int n; 352 353 for (;;) { 354 /* Grab the next inode number */ 355 ino = devfs_nextino; 356 i = ino + 1; 357 /* wrap around when we reach the end */ 358 if (i >= NDEVFSINO + devfs_noverflow) 359 i = 3; 360 devfs_nextino = i; 361 362 /* see if it was occupied */ 363 dp = devfs_itod(ino); 364 KASSERT(dp != NULL, ("DEVFS: No devptr inode %d", ino)); 365 if (*dp != NULL) 366 continue; 367 ip = devfs_itor(ino); 368 KASSERT(ip != NULL, ("DEVFS: No iptr inode %d", ino)); 369 if (*ip != 0) 370 continue; 371 break; 372 } 373 374 *dp = dev; 375 dev->si_inode = ino; 376 if (i > devfs_topino) 377 devfs_topino = i; 378 379 devfs_numino++; 380 devfs_generation++; 381 382 if (devfs_overflow != NULL || devfs_numino + 100 < NDEVFSINO) 383 return; 384 385 /* 386 * Try to allocate overflow table 387 * XXX: we can probably be less panicy these days and a linked 388 * XXX: list of PAGESIZE/PTRSIZE entries might be a better idea. 389 * 390 * XXX: we may be into witness unlove here. 391 */ 392 n = devfs_noverflowwant; 393 ot = malloc(sizeof(*ot) * n, M_DEVFS, M_NOWAIT | M_ZERO); 394 if (ot == NULL) 395 return; 396 or = malloc(sizeof(*or) * n, M_DEVFS, M_NOWAIT | M_ZERO); 397 if (or == NULL) { 398 free(ot, M_DEVFS); 399 return; 400 } 401 devfs_overflow = ot; 402 devfs_refoverflow = or; 403 devfs_noverflow = n; 404 printf("DEVFS Overflow table with %d entries allocated\n", n); 405 return; 406 } 407 408 void 409 devfs_destroy(struct cdev *dev) 410 { 411 int ino; 412 struct cdev **dp; 413 414 ino = dev->si_inode; 415 dev->si_inode = 0; 416 if (ino == 0) 417 return; 418 dp = devfs_itod(ino); 419 KASSERT(*dp == dev, 420 ("DEVFS: destroying wrong cdev ino %d", ino)); 421 *dp = NULL; 422 devfs_numino--; 423 devfs_generation++; 424 if (ino < devfs_nextino) 425 devfs_nextino = ino; 426 } 427