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 34 #include <sys/param.h> 35 #include <sys/systm.h> 36 #include <sys/dirent.h> 37 #include <sys/conf.h> 38 #include <sys/vnode.h> 39 #include <sys/malloc.h> 40 #include <sys/sysctl.h> 41 #include <sys/kernel.h> 42 #include <sys/lock.h> 43 44 #include <machine/atomic.h> 45 46 #include <fs/devfs/devfs.h> 47 48 static dev_t devfs_inot[NDEVFSINO]; 49 static dev_t *devfs_overflow; 50 static int devfs_ref[NDEVFSINO]; 51 static int *devfs_refoverflow; 52 static int devfs_nextino = 3; 53 static int devfs_numino; 54 static int devfs_topino; 55 static int devfs_noverflowwant = NDEVFSOVERFLOW; 56 static int devfs_noverflow; 57 static unsigned devfs_generation; 58 59 SYSCTL_NODE(_vfs, OID_AUTO, devfs, CTLFLAG_RW, 0, "DEVFS filesystem"); 60 SYSCTL_UINT(_vfs_devfs, OID_AUTO, noverflow, CTLFLAG_RW, 61 &devfs_noverflowwant, 0, "Size of DEVFS overflow table"); 62 SYSCTL_UINT(_vfs_devfs, OID_AUTO, generation, CTLFLAG_RD, 63 &devfs_generation, 0, "DEVFS generation number"); 64 SYSCTL_UINT(_vfs_devfs, OID_AUTO, inodes, CTLFLAG_RD, 65 &devfs_numino, 0, "DEVFS inodes"); 66 SYSCTL_UINT(_vfs_devfs, OID_AUTO, topinode, CTLFLAG_RD, 67 &devfs_topino, 0, "DEVFS highest inode#"); 68 69 static int * 70 devfs_itor(int inode) 71 { 72 if (inode < NDEVFSINO) 73 return (&devfs_ref[inode]); 74 else if (inode < NDEVFSINO + devfs_noverflow) 75 return (&devfs_refoverflow[inode - NDEVFSINO]); 76 else 77 panic ("YRK!"); 78 } 79 80 static void 81 devfs_dropref(int inode) 82 { 83 int *ip; 84 85 ip = devfs_itor(inode); 86 atomic_add_int(ip, -1); 87 } 88 89 static int 90 devfs_getref(int inode) 91 { 92 int *ip, i, j; 93 dev_t *dp; 94 95 ip = devfs_itor(inode); 96 dp = devfs_itod(inode); 97 for (;;) { 98 i = *ip; 99 j = i + 1; 100 if (!atomic_cmpset_int(ip, i, j)) 101 continue; 102 if (*dp != NULL) 103 return (1); 104 atomic_add_int(ip, -1); 105 return(0); 106 } 107 } 108 109 struct devfs_dirent ** 110 devfs_itode (struct devfs_mount *dm, int inode) 111 { 112 113 if (inode < NDEVFSINO) 114 return (&dm->dm_dirent[inode]); 115 if (devfs_overflow == NULL) 116 return (NULL); 117 if (inode < NDEVFSINO + devfs_noverflow) 118 return (&dm->dm_overflow[inode - NDEVFSINO]); 119 return (NULL); 120 } 121 122 dev_t * 123 devfs_itod (int inode) 124 { 125 126 if (inode < NDEVFSINO) 127 return (&devfs_inot[inode]); 128 if (devfs_overflow == NULL) 129 return (NULL); 130 if (inode < NDEVFSINO + devfs_noverflow) 131 return (&devfs_overflow[inode - NDEVFSINO]); 132 return (NULL); 133 } 134 135 void 136 devfs_attemptoverflow(int insist) 137 { 138 dev_t **ot; 139 int *or; 140 int n, nb; 141 142 /* Check if somebody beat us to it */ 143 if (devfs_overflow != NULL) 144 return; 145 ot = NULL; 146 or = NULL; 147 n = devfs_noverflowwant; 148 nb = sizeof (struct dev_t *) * n; 149 MALLOC(ot, dev_t **, nb, M_DEVFS, insist ? M_WAITOK : M_NOWAIT); 150 if (ot == NULL) 151 goto bail; 152 bzero(ot, nb); 153 nb = sizeof (int) * n; 154 MALLOC(or, int *, nb, M_DEVFS, insist ? M_WAITOK : M_NOWAIT); 155 if (or == NULL) 156 goto bail; 157 bzero(or, nb); 158 if (!atomic_cmpset_ptr(&devfs_overflow, NULL, ot)) 159 goto bail; 160 devfs_refoverflow = or; 161 devfs_noverflow = n; 162 printf("DEVFS Overflow table with %d entries allocated when %d in use\n", n, devfs_numino); 163 return; 164 165 bail: 166 /* Somebody beat us to it, or something went wrong. */ 167 if (ot != NULL) 168 FREE(ot, M_DEVFS); 169 if (or != NULL) 170 FREE(or, M_DEVFS); 171 return; 172 } 173 174 struct devfs_dirent * 175 devfs_find(struct devfs_dirent *dd, const char *name, int namelen) 176 { 177 struct devfs_dirent *de; 178 179 TAILQ_FOREACH(de, &dd->de_dlist, de_list) { 180 if (namelen != de->de_dirent->d_namlen) 181 continue; 182 if (bcmp(name, de->de_dirent->d_name, namelen) != 0) 183 continue; 184 break; 185 } 186 return (de); 187 } 188 189 struct devfs_dirent * 190 devfs_newdirent(char *name, int namelen) 191 { 192 int i; 193 struct devfs_dirent *de; 194 struct dirent d; 195 196 d.d_namlen = namelen; 197 i = sizeof (*de) + GENERIC_DIRSIZ(&d); 198 MALLOC(de, struct devfs_dirent *, i, M_DEVFS, M_WAITOK); 199 bzero(de, i); 200 de->de_dirent = (struct dirent *)(de + 1); 201 de->de_dirent->d_namlen = namelen; 202 de->de_dirent->d_reclen = GENERIC_DIRSIZ(&d); 203 bcopy(name, de->de_dirent->d_name, namelen + 1); 204 nanotime(&de->de_ctime); 205 de->de_mtime = de->de_atime = de->de_ctime; 206 de->de_links = 1; 207 return (de); 208 } 209 210 struct devfs_dirent * 211 devfs_vmkdir(char *name, int namelen, struct devfs_dirent *dotdot) 212 { 213 struct devfs_dirent *dd; 214 struct devfs_dirent *de; 215 216 dd = devfs_newdirent(name, namelen); 217 218 TAILQ_INIT(&dd->de_dlist); 219 220 dd->de_dirent->d_type = DT_DIR; 221 dd->de_mode = 0755; 222 dd->de_links = 2; 223 dd->de_dir = dd; 224 225 de = devfs_newdirent(".", 1); 226 de->de_dirent->d_type = DT_DIR; 227 de->de_dir = dd; 228 de->de_flags |= DE_DOT; 229 TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list); 230 231 de = devfs_newdirent("..", 2); 232 de->de_dirent->d_type = DT_DIR; 233 if (dotdot == NULL) 234 de->de_dir = dd; 235 else 236 de->de_dir = dotdot; 237 de->de_flags |= DE_DOTDOT; 238 TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list); 239 240 return (dd); 241 } 242 243 static void 244 devfs_delete(struct devfs_dirent *dd, struct devfs_dirent *de) 245 { 246 247 if (de->de_symlink) { 248 FREE(de->de_symlink, M_DEVFS); 249 de->de_symlink = NULL; 250 } 251 if (de->de_vnode) 252 de->de_vnode->v_data = NULL; 253 TAILQ_REMOVE(&dd->de_dlist, de, de_list); 254 FREE(de, M_DEVFS); 255 } 256 257 void 258 devfs_purge(struct devfs_dirent *dd) 259 { 260 struct devfs_dirent *de; 261 262 for (;;) { 263 de = TAILQ_FIRST(&dd->de_dlist); 264 if (de == NULL) 265 break; 266 devfs_delete(dd, de); 267 } 268 FREE(dd, M_DEVFS); 269 } 270 271 272 int 273 devfs_populate(struct devfs_mount *dm) 274 { 275 int i, j; 276 dev_t dev, pdev; 277 struct devfs_dirent *dd; 278 struct devfs_dirent *de, **dep; 279 char *q, *s; 280 281 if (dm->dm_generation == devfs_generation) 282 return (0); 283 lockmgr(&dm->dm_lock, LK_UPGRADE, 0, curproc); 284 if (devfs_noverflow && dm->dm_overflow == NULL) { 285 i = devfs_noverflow * sizeof (struct devfs_dirent *); 286 MALLOC(dm->dm_overflow, struct devfs_dirent **, i, 287 M_DEVFS, M_WAITOK); 288 bzero(dm->dm_overflow, i); 289 } 290 while (dm->dm_generation != devfs_generation) { 291 dm->dm_generation = devfs_generation; 292 for (i = 0; i <= devfs_topino; i++) { 293 dev = *devfs_itod(i); 294 dep = devfs_itode(dm, i); 295 de = *dep; 296 if (dev == NULL && de == DE_DELETED) { 297 *dep = NULL; 298 continue; 299 } 300 if (dev == NULL && de != NULL) { 301 dd = de->de_dir; 302 *dep = NULL; 303 TAILQ_REMOVE(&dd->de_dlist, de, de_list); 304 if (de->de_vnode) 305 de->de_vnode->v_data = NULL; 306 FREE(de, M_DEVFS); 307 devfs_dropref(i); 308 continue; 309 } 310 if (dev == NULL) 311 continue; 312 if (de != NULL) 313 continue; 314 if (!devfs_getref(i)) 315 continue; 316 dd = dm->dm_basedir; 317 s = dev->si_name; 318 for (;;) { 319 for (q = s; *q != '/' && *q != '\0'; q++) 320 continue; 321 if (*q != '/') 322 break; 323 de = devfs_find(dd, s, q - s); 324 if (de == NULL) { 325 de = devfs_vmkdir(s, q - s, dd); 326 de->de_inode = dm->dm_inode++; 327 TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list); 328 dd->de_links++; 329 } 330 s = q + 1; 331 dd = de; 332 } 333 de = devfs_newdirent(s, q - s); 334 if (dev->si_flags & SI_ALIAS) { 335 de->de_inode = dm->dm_inode++; 336 de->de_uid = 0; 337 de->de_gid = 0; 338 de->de_mode = 0666; 339 de->de_dirent->d_type = DT_LNK; 340 pdev = dev->si_drv1; 341 j = strlen(pdev->si_name) + 1; 342 MALLOC(de->de_symlink, char *, j, M_DEVFS, M_WAITOK); 343 bcopy(pdev->si_name, de->de_symlink, j); 344 } else { 345 de->de_inode = i; 346 de->de_uid = dev->si_uid; 347 de->de_gid = dev->si_gid; 348 de->de_mode = dev->si_mode; 349 de->de_dirent->d_type = DT_CHR; 350 } 351 *dep = de; 352 de->de_dir = dd; 353 TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list); 354 #if 0 355 printf("Add ino%d %s\n", i, dev->si_name); 356 #endif 357 } 358 } 359 lockmgr(&dm->dm_lock, LK_DOWNGRADE, 0, curproc); 360 return (0); 361 } 362 363 static void 364 devfs_create(dev_t dev) 365 { 366 int ino, i, *ip; 367 dev_t *dp; 368 369 for (;;) { 370 /* Grab the next inode number */ 371 ino = devfs_nextino; 372 i = ino + 1; 373 /* wrap around when we reach the end */ 374 if (i >= NDEVFSINO + devfs_noverflow) 375 i = 3; 376 if (!atomic_cmpset_int(&devfs_nextino, ino, i)) 377 continue; 378 379 /* see if it was occupied */ 380 dp = devfs_itod(ino); 381 if (dp == NULL) 382 Debugger("dp == NULL\n"); 383 if (*dp != NULL) 384 continue; 385 ip = devfs_itor(ino); 386 if (ip == NULL) 387 Debugger("ip == NULL\n"); 388 if (*ip != 0) 389 continue; 390 391 if (!atomic_cmpset_ptr(dp, NULL, dev)) 392 continue; 393 394 dev->si_inode = ino; 395 for (;;) { 396 i = devfs_topino; 397 if (i >= ino) 398 break; 399 if (atomic_cmpset_int(&devfs_topino, i, ino)) 400 break; 401 printf("failed topino %d %d\n", i, ino); 402 } 403 break; 404 } 405 406 atomic_add_int(&devfs_numino, 1); 407 atomic_add_int(&devfs_generation, 1); 408 if (devfs_overflow == NULL && devfs_numino + 100 > NDEVFSINO) 409 devfs_attemptoverflow(0); 410 } 411 412 static void 413 devfs_destroy(dev_t dev) 414 { 415 int ino, i; 416 417 ino = dev->si_inode; 418 dev->si_inode = 0; 419 if (ino == 0) 420 return; 421 if (atomic_cmpset_ptr(devfs_itod(ino), dev, NULL)) { 422 atomic_add_int(&devfs_generation, 1); 423 atomic_add_int(&devfs_numino, -1); 424 i = devfs_nextino; 425 if (ino < i) 426 atomic_cmpset_int(&devfs_nextino, i, ino); 427 } 428 } 429 430 devfs_create_t *devfs_create_hook = devfs_create; 431 devfs_destroy_t *devfs_destroy_hook = devfs_destroy; 432 int devfs_present = 1; 433