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/proc.h> 40 #include <sys/malloc.h> 41 #include <sys/sysctl.h> 42 #include <sys/kernel.h> 43 #include <sys/lock.h> 44 45 #include <machine/atomic.h> 46 47 #include <fs/devfs/devfs.h> 48 49 static dev_t devfs_inot[NDEVFSINO]; 50 static dev_t *devfs_overflow; 51 static int devfs_ref[NDEVFSINO]; 52 static int *devfs_refoverflow; 53 static int devfs_nextino = 3; 54 static int devfs_numino; 55 static int devfs_topino; 56 static int devfs_noverflowwant = NDEVFSOVERFLOW; 57 static int devfs_noverflow; 58 static unsigned devfs_generation; 59 60 SYSCTL_NODE(_vfs, OID_AUTO, devfs, CTLFLAG_RW, 0, "DEVFS filesystem"); 61 SYSCTL_UINT(_vfs_devfs, OID_AUTO, noverflow, CTLFLAG_RW, 62 &devfs_noverflowwant, 0, "Size of DEVFS overflow table"); 63 SYSCTL_UINT(_vfs_devfs, OID_AUTO, generation, CTLFLAG_RD, 64 &devfs_generation, 0, "DEVFS generation number"); 65 SYSCTL_UINT(_vfs_devfs, OID_AUTO, inodes, CTLFLAG_RD, 66 &devfs_numino, 0, "DEVFS inodes"); 67 SYSCTL_UINT(_vfs_devfs, OID_AUTO, topinode, CTLFLAG_RD, 68 &devfs_topino, 0, "DEVFS highest inode#"); 69 70 static int * 71 devfs_itor(int inode) 72 { 73 if (inode < NDEVFSINO) 74 return (&devfs_ref[inode]); 75 else if (inode < NDEVFSINO + devfs_noverflow) 76 return (&devfs_refoverflow[inode - NDEVFSINO]); 77 else 78 panic ("YRK!"); 79 } 80 81 static void 82 devfs_dropref(int inode) 83 { 84 int *ip; 85 86 ip = devfs_itor(inode); 87 atomic_add_int(ip, -1); 88 } 89 90 static int 91 devfs_getref(int inode) 92 { 93 int *ip, i, j; 94 dev_t *dp; 95 96 ip = devfs_itor(inode); 97 dp = devfs_itod(inode); 98 for (;;) { 99 i = *ip; 100 j = i + 1; 101 if (!atomic_cmpset_int(ip, i, j)) 102 continue; 103 if (*dp != NULL) 104 return (1); 105 atomic_add_int(ip, -1); 106 return(0); 107 } 108 } 109 110 struct devfs_dirent ** 111 devfs_itode (struct devfs_mount *dm, int inode) 112 { 113 114 if (inode < NDEVFSINO) 115 return (&dm->dm_dirent[inode]); 116 if (devfs_overflow == NULL) 117 return (NULL); 118 if (inode < NDEVFSINO + devfs_noverflow) 119 return (&dm->dm_overflow[inode - NDEVFSINO]); 120 return (NULL); 121 } 122 123 dev_t * 124 devfs_itod (int inode) 125 { 126 127 if (inode < NDEVFSINO) 128 return (&devfs_inot[inode]); 129 if (devfs_overflow == NULL) 130 return (NULL); 131 if (inode < NDEVFSINO + devfs_noverflow) 132 return (&devfs_overflow[inode - NDEVFSINO]); 133 return (NULL); 134 } 135 136 void 137 devfs_attemptoverflow(int insist) 138 { 139 dev_t **ot; 140 int *or; 141 int n, nb; 142 143 /* Check if somebody beat us to it */ 144 if (devfs_overflow != NULL) 145 return; 146 ot = NULL; 147 or = NULL; 148 n = devfs_noverflowwant; 149 nb = sizeof (struct dev_t *) * n; 150 MALLOC(ot, dev_t **, nb, M_DEVFS, insist ? M_WAITOK : M_NOWAIT); 151 if (ot == NULL) 152 goto bail; 153 bzero(ot, nb); 154 nb = sizeof (int) * n; 155 MALLOC(or, int *, nb, M_DEVFS, insist ? M_WAITOK : M_NOWAIT); 156 if (or == NULL) 157 goto bail; 158 bzero(or, nb); 159 if (!atomic_cmpset_ptr(&devfs_overflow, NULL, ot)) 160 goto bail; 161 devfs_refoverflow = or; 162 devfs_noverflow = n; 163 printf("DEVFS Overflow table with %d entries allocated when %d in use\n", n, devfs_numino); 164 return; 165 166 bail: 167 /* Somebody beat us to it, or something went wrong. */ 168 if (ot != NULL) 169 FREE(ot, M_DEVFS); 170 if (or != NULL) 171 FREE(or, M_DEVFS); 172 return; 173 } 174 175 struct devfs_dirent * 176 devfs_find(struct devfs_dirent *dd, const char *name, int namelen) 177 { 178 struct devfs_dirent *de; 179 180 TAILQ_FOREACH(de, &dd->de_dlist, de_list) { 181 if (namelen != de->de_dirent->d_namlen) 182 continue; 183 if (bcmp(name, de->de_dirent->d_name, namelen) != 0) 184 continue; 185 break; 186 } 187 return (de); 188 } 189 190 struct devfs_dirent * 191 devfs_newdirent(char *name, int namelen) 192 { 193 int i; 194 struct devfs_dirent *de; 195 struct dirent d; 196 197 d.d_namlen = namelen; 198 i = sizeof (*de) + GENERIC_DIRSIZ(&d); 199 MALLOC(de, struct devfs_dirent *, i, M_DEVFS, M_WAITOK); 200 bzero(de, i); 201 de->de_dirent = (struct dirent *)(de + 1); 202 de->de_dirent->d_namlen = namelen; 203 de->de_dirent->d_reclen = GENERIC_DIRSIZ(&d); 204 bcopy(name, de->de_dirent->d_name, namelen + 1); 205 nanotime(&de->de_ctime); 206 de->de_mtime = de->de_atime = de->de_ctime; 207 de->de_links = 1; 208 return (de); 209 } 210 211 struct devfs_dirent * 212 devfs_vmkdir(char *name, int namelen, struct devfs_dirent *dotdot) 213 { 214 struct devfs_dirent *dd; 215 struct devfs_dirent *de; 216 217 dd = devfs_newdirent(name, namelen); 218 219 TAILQ_INIT(&dd->de_dlist); 220 221 dd->de_dirent->d_type = DT_DIR; 222 dd->de_mode = 0755; 223 dd->de_links = 2; 224 dd->de_dir = dd; 225 226 de = devfs_newdirent(".", 1); 227 de->de_dirent->d_type = DT_DIR; 228 de->de_dir = dd; 229 de->de_flags |= DE_DOT; 230 TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list); 231 232 de = devfs_newdirent("..", 2); 233 de->de_dirent->d_type = DT_DIR; 234 if (dotdot == NULL) 235 de->de_dir = dd; 236 else 237 de->de_dir = dotdot; 238 de->de_flags |= DE_DOTDOT; 239 TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list); 240 241 return (dd); 242 } 243 244 static void 245 devfs_delete(struct devfs_dirent *dd, struct devfs_dirent *de) 246 { 247 248 if (de->de_symlink) { 249 FREE(de->de_symlink, M_DEVFS); 250 de->de_symlink = NULL; 251 } 252 if (de->de_vnode) 253 de->de_vnode->v_data = NULL; 254 TAILQ_REMOVE(&dd->de_dlist, de, de_list); 255 FREE(de, M_DEVFS); 256 } 257 258 void 259 devfs_purge(struct devfs_dirent *dd) 260 { 261 struct devfs_dirent *de; 262 263 for (;;) { 264 de = TAILQ_FIRST(&dd->de_dlist); 265 if (de == NULL) 266 break; 267 devfs_delete(dd, de); 268 } 269 FREE(dd, M_DEVFS); 270 } 271 272 273 int 274 devfs_populate(struct devfs_mount *dm) 275 { 276 int i, j; 277 dev_t dev, pdev; 278 struct devfs_dirent *dd; 279 struct devfs_dirent *de, **dep; 280 char *q, *s; 281 282 if (dm->dm_generation == devfs_generation) 283 return (0); 284 lockmgr(&dm->dm_lock, LK_UPGRADE, 0, curproc); 285 if (devfs_noverflow && dm->dm_overflow == NULL) { 286 i = devfs_noverflow * sizeof (struct devfs_dirent *); 287 MALLOC(dm->dm_overflow, struct devfs_dirent **, i, 288 M_DEVFS, M_WAITOK); 289 bzero(dm->dm_overflow, i); 290 } 291 while (dm->dm_generation != devfs_generation) { 292 dm->dm_generation = devfs_generation; 293 for (i = 0; i <= devfs_topino; i++) { 294 dev = *devfs_itod(i); 295 dep = devfs_itode(dm, i); 296 de = *dep; 297 if (dev == NULL && de == DE_DELETED) { 298 *dep = NULL; 299 continue; 300 } 301 if (dev == NULL && de != NULL) { 302 dd = de->de_dir; 303 *dep = NULL; 304 TAILQ_REMOVE(&dd->de_dlist, de, de_list); 305 if (de->de_vnode) 306 de->de_vnode->v_data = NULL; 307 FREE(de, M_DEVFS); 308 devfs_dropref(i); 309 continue; 310 } 311 if (dev == NULL) 312 continue; 313 if (de != NULL) 314 continue; 315 if (!devfs_getref(i)) 316 continue; 317 dd = dm->dm_basedir; 318 s = dev->si_name; 319 for (;;) { 320 for (q = s; *q != '/' && *q != '\0'; q++) 321 continue; 322 if (*q != '/') 323 break; 324 de = devfs_find(dd, s, q - s); 325 if (de == NULL) { 326 de = devfs_vmkdir(s, q - s, dd); 327 de->de_inode = dm->dm_inode++; 328 TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list); 329 dd->de_links++; 330 } 331 s = q + 1; 332 dd = de; 333 } 334 de = devfs_newdirent(s, q - s); 335 if (dev->si_flags & SI_ALIAS) { 336 de->de_inode = dm->dm_inode++; 337 de->de_uid = 0; 338 de->de_gid = 0; 339 de->de_mode = 0666; 340 de->de_dirent->d_type = DT_LNK; 341 pdev = dev->si_drv1; 342 j = strlen(pdev->si_name) + 1; 343 MALLOC(de->de_symlink, char *, j, M_DEVFS, M_WAITOK); 344 bcopy(pdev->si_name, de->de_symlink, j); 345 } else { 346 de->de_inode = i; 347 de->de_uid = dev->si_uid; 348 de->de_gid = dev->si_gid; 349 de->de_mode = dev->si_mode; 350 de->de_dirent->d_type = DT_CHR; 351 } 352 *dep = de; 353 de->de_dir = dd; 354 TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list); 355 #if 0 356 printf("Add ino%d %s\n", i, dev->si_name); 357 #endif 358 } 359 } 360 lockmgr(&dm->dm_lock, LK_DOWNGRADE, 0, curproc); 361 return (0); 362 } 363 364 static void 365 devfs_create(dev_t dev) 366 { 367 int ino, i, *ip; 368 dev_t *dp; 369 370 for (;;) { 371 /* Grab the next inode number */ 372 ino = devfs_nextino; 373 i = ino + 1; 374 /* wrap around when we reach the end */ 375 if (i >= NDEVFSINO + devfs_noverflow) 376 i = 3; 377 if (!atomic_cmpset_int(&devfs_nextino, ino, i)) 378 continue; 379 380 /* see if it was occupied */ 381 dp = devfs_itod(ino); 382 if (dp == NULL) 383 Debugger("dp == NULL\n"); 384 if (*dp != NULL) 385 continue; 386 ip = devfs_itor(ino); 387 if (ip == NULL) 388 Debugger("ip == NULL\n"); 389 if (*ip != 0) 390 continue; 391 392 if (!atomic_cmpset_ptr(dp, NULL, dev)) 393 continue; 394 395 dev->si_inode = ino; 396 for (;;) { 397 i = devfs_topino; 398 if (i >= ino) 399 break; 400 if (atomic_cmpset_int(&devfs_topino, i, ino)) 401 break; 402 printf("failed topino %d %d\n", i, ino); 403 } 404 break; 405 } 406 407 atomic_add_int(&devfs_numino, 1); 408 atomic_add_int(&devfs_generation, 1); 409 if (devfs_overflow == NULL && devfs_numino + 100 > NDEVFSINO) 410 devfs_attemptoverflow(0); 411 } 412 413 static void 414 devfs_destroy(dev_t dev) 415 { 416 int ino, i; 417 418 ino = dev->si_inode; 419 dev->si_inode = 0; 420 if (ino == 0) 421 return; 422 if (atomic_cmpset_ptr(devfs_itod(ino), dev, NULL)) { 423 atomic_add_int(&devfs_generation, 1); 424 atomic_add_int(&devfs_numino, -1); 425 i = devfs_nextino; 426 if (ino < i) 427 atomic_cmpset_int(&devfs_nextino, i, ino); 428 } 429 } 430 431 devfs_create_t *devfs_create_hook = devfs_create; 432 devfs_destroy_t *devfs_destroy_hook = devfs_destroy; 433 int devfs_present = 1; 434