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