ufs.c revision 1.3
1 /*- 2 * Copyright (c) 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * The Mach Operating System project at Carnegie-Mellon University. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * from: @(#)ufs.c 8.1 (Berkeley) 6/11/93 37 * 38 * 39 * Copyright (c) 1990, 1991 Carnegie Mellon University 40 * All Rights Reserved. 41 * 42 * Author: David Golub 43 * 44 * Permission to use, copy, modify and distribute this software and its 45 * documentation is hereby granted, provided that both the copyright 46 * notice and this permission notice appear in all copies of the 47 * software, derivative works or modified versions, and any portions 48 * thereof, and that both notices appear in supporting documentation. 49 * 50 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 51 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR 52 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 53 * 54 * Carnegie Mellon requests users of this software to return to 55 * 56 * Software Distribution Coordinator or Software.Distribution (at) CS.CMU.EDU 57 * School of Computer Science 58 * Carnegie Mellon University 59 * Pittsburgh PA 15213-3890 60 * 61 * any improvements or extensions that they make and grant Carnegie the 62 * rights to redistribute these changes. 63 * 64 * $Id: ufs.c,v 1.3 1994/06/20 08:39:01 pk Exp $ 65 */ 66 67 /* 68 * Stand-alone file reading package. 69 */ 70 71 #include <sys/param.h> 72 #include <sys/time.h> 73 #include <ufs/ffs/fs.h> 74 #include <ufs/ufs/dinode.h> 75 #include <ufs/ufs/dir.h> 76 77 #include "stand.h" 78 79 /* 80 * In-core open file. 81 */ 82 struct file { 83 off_t f_seekp; /* seek pointer */ 84 struct fs *f_fs; /* pointer to super-block */ 85 struct dinode f_di; /* copy of on-disk inode */ 86 int f_nindir[NIADDR]; 87 /* number of blocks mapped by 88 indirect block at level i */ 89 char *f_blk[NIADDR]; /* buffer for indirect block at 90 level i */ 91 u_long f_blksize[NIADDR]; 92 /* size of buffer */ 93 daddr_t f_blkno[NIADDR];/* disk address of block in buffer */ 94 char *f_buf; /* buffer for data block */ 95 u_int f_buf_size; /* size of data block */ 96 daddr_t f_buf_blkno; /* block number of data block */ 97 }; 98 99 /* 100 * Read a new inode into a file structure. 101 */ 102 static int 103 read_inode(inumber, f) 104 ino_t inumber; 105 struct open_file *f; 106 { 107 register struct file *fp = (struct file *)f->f_fsdata; 108 register struct fs *fs = fp->f_fs; 109 char *buf; 110 u_int rsize; 111 int rc; 112 113 /* 114 * Read inode and save it. 115 */ 116 buf = alloc(fs->fs_bsize); 117 rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ, 118 fsbtodb(fs, ino_to_fsba(fs, inumber)), fs->fs_bsize, buf, &rsize); 119 if (rc) 120 goto out; 121 if (rsize != fs->fs_bsize) { 122 rc = EIO; 123 goto out; 124 } 125 126 { 127 register struct dinode *dp; 128 129 dp = (struct dinode *)buf; 130 fp->f_di = dp[ino_to_fsbo(fs, inumber)]; 131 } 132 133 /* 134 * Clear out the old buffers 135 */ 136 { 137 register int level; 138 139 for (level = 0; level < NIADDR; level++) 140 fp->f_blkno[level] = -1; 141 fp->f_buf_blkno = -1; 142 } 143 out: 144 free(buf, fs->fs_bsize); 145 return (0); 146 } 147 148 /* 149 * Given an offset in a file, find the disk block number that 150 * contains that block. 151 */ 152 static int 153 block_map(f, file_block, disk_block_p) 154 struct open_file *f; 155 daddr_t file_block; 156 daddr_t *disk_block_p; /* out */ 157 { 158 register struct file *fp = (struct file *)f->f_fsdata; 159 register struct fs *fs = fp->f_fs; 160 int level; 161 int idx; 162 daddr_t ind_block_num; 163 daddr_t *ind_p; 164 int rc; 165 166 /* 167 * Index structure of an inode: 168 * 169 * di_db[0..NDADDR-1] hold block numbers for blocks 170 * 0..NDADDR-1 171 * 172 * di_ib[0] index block 0 is the single indirect block 173 * holds block numbers for blocks 174 * NDADDR .. NDADDR + NINDIR(fs)-1 175 * 176 * di_ib[1] index block 1 is the double indirect block 177 * holds block numbers for INDEX blocks for blocks 178 * NDADDR + NINDIR(fs) .. 179 * NDADDR + NINDIR(fs) + NINDIR(fs)**2 - 1 180 * 181 * di_ib[2] index block 2 is the triple indirect block 182 * holds block numbers for double-indirect 183 * blocks for blocks 184 * NDADDR + NINDIR(fs) + NINDIR(fs)**2 .. 185 * NDADDR + NINDIR(fs) + NINDIR(fs)**2 186 * + NINDIR(fs)**3 - 1 187 */ 188 189 if (file_block < NDADDR) { 190 /* Direct block. */ 191 *disk_block_p = fp->f_di.di_db[file_block]; 192 return (0); 193 } 194 195 file_block -= NDADDR; 196 197 /* 198 * nindir[0] = NINDIR 199 * nindir[1] = NINDIR**2 200 * nindir[2] = NINDIR**3 201 * etc 202 */ 203 for (level = 0; level < NIADDR; level++) { 204 if (file_block < fp->f_nindir[level]) 205 break; 206 file_block -= fp->f_nindir[level]; 207 } 208 if (level == NIADDR) { 209 /* Block number too high */ 210 return (EFBIG); 211 } 212 213 ind_block_num = fp->f_di.di_ib[level]; 214 215 for (; level >= 0; level--) { 216 if (ind_block_num == 0) { 217 *disk_block_p = 0; /* missing */ 218 return (0); 219 } 220 221 if (fp->f_blkno[level] != ind_block_num) { 222 if (fp->f_blk[level] == (char *)0) 223 fp->f_blk[level] = 224 alloc(fs->fs_bsize); 225 rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ, 226 fsbtodb(fp->f_fs, ind_block_num), 227 fs->fs_bsize, 228 fp->f_blk[level], 229 (u_int *)&fp->f_blksize[level]); 230 if (rc) 231 return (rc); 232 if (fp->f_blksize[level] != fs->fs_bsize) 233 return (EIO); 234 fp->f_blkno[level] = ind_block_num; 235 } 236 237 ind_p = (daddr_t *)fp->f_blk[level]; 238 239 if (level > 0) { 240 idx = file_block / fp->f_nindir[level - 1]; 241 file_block %= fp->f_nindir[level - 1]; 242 } else 243 idx = file_block; 244 245 ind_block_num = ind_p[idx]; 246 } 247 248 *disk_block_p = ind_block_num; 249 250 return (0); 251 } 252 253 /* 254 * Read a portion of a file into an internal buffer. Return 255 * the location in the buffer and the amount in the buffer. 256 */ 257 static int 258 buf_read_file(f, buf_p, size_p) 259 struct open_file *f; 260 char **buf_p; /* out */ 261 u_int *size_p; /* out */ 262 { 263 register struct file *fp = (struct file *)f->f_fsdata; 264 register struct fs *fs = fp->f_fs; 265 long off; 266 register daddr_t file_block; 267 daddr_t disk_block; 268 long block_size; 269 int rc; 270 271 off = blkoff(fs, fp->f_seekp); 272 file_block = lblkno(fs, fp->f_seekp); 273 block_size = dblksize(fs, &fp->f_di, file_block); 274 275 if (file_block != fp->f_buf_blkno) { 276 rc = block_map(f, file_block, &disk_block); 277 if (rc) 278 return (rc); 279 280 if (fp->f_buf == (char *)0) 281 fp->f_buf = alloc(fs->fs_bsize); 282 283 if (disk_block == 0) { 284 bzero(fp->f_buf, block_size); 285 fp->f_buf_size = block_size; 286 } else { 287 rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ, 288 fsbtodb(fs, disk_block), 289 block_size, fp->f_buf, &fp->f_buf_size); 290 if (rc) 291 return (rc); 292 } 293 294 fp->f_buf_blkno = file_block; 295 } 296 297 /* 298 * Return address of byte in buffer corresponding to 299 * offset, and size of remainder of buffer after that 300 * byte. 301 */ 302 *buf_p = fp->f_buf + off; 303 *size_p = block_size - off; 304 305 /* 306 * But truncate buffer at end of file. 307 */ 308 if (*size_p > fp->f_di.di_size - fp->f_seekp) 309 *size_p = fp->f_di.di_size - fp->f_seekp; 310 311 return (0); 312 } 313 314 /* 315 * Search a directory for a name and return its 316 * i_number. 317 */ 318 static int 319 search_directory(name, f, inumber_p) 320 char *name; 321 struct open_file *f; 322 ino_t *inumber_p; /* out */ 323 { 324 register struct file *fp = (struct file *)f->f_fsdata; 325 register struct direct *dp; 326 struct direct *edp; 327 char *buf; 328 u_int buf_size; 329 int namlen, length; 330 int rc; 331 332 length = strlen(name); 333 334 fp->f_seekp = 0; 335 while (fp->f_seekp < fp->f_di.di_size) { 336 rc = buf_read_file(f, &buf, &buf_size); 337 if (rc) 338 return (rc); 339 340 dp = (struct direct *)buf; 341 edp = (struct direct *)(buf + buf_size); 342 while (dp < edp) { 343 if (dp->d_ino == (ino_t)0) 344 goto next; 345 #if 0 346 #if BYTE_ORDER == LITTLE_ENDIAN 347 if (fp->f_fs->fs_maxsymlinklen <= 0) 348 namlen = dp->d_type; 349 else 350 #endif 351 #endif 352 namlen = dp->d_namlen; 353 if (namlen == length && 354 !strcmp(name, dp->d_name)) { 355 /* found entry */ 356 *inumber_p = dp->d_ino; 357 return (0); 358 } 359 next: 360 dp = (struct direct *)((char *)dp + dp->d_reclen); 361 } 362 fp->f_seekp += buf_size; 363 } 364 return (ENOENT); 365 } 366 367 /* 368 * Open a file. 369 */ 370 int 371 ufs_open(path, f) 372 char *path; 373 struct open_file *f; 374 { 375 register char *cp, *ncp; 376 register int c; 377 ino_t inumber, parent_inumber; 378 int nlinks = 0; 379 struct file *fp; 380 struct fs *fs; 381 int rc; 382 u_int buf_size; 383 #if 0 384 char namebuf[MAXPATHLEN+1]; 385 #endif 386 387 /* allocate file system specific data structure */ 388 fp = alloc(sizeof(struct file)); 389 bzero(fp, sizeof(struct file)); 390 f->f_fsdata = (void *)fp; 391 392 /* allocate space and read super block */ 393 fs = alloc(SBSIZE); 394 fp->f_fs = fs; 395 rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ, 396 SBLOCK, SBSIZE, (char *)fs, &buf_size); 397 if (rc) 398 goto out; 399 400 if (buf_size != SBSIZE || fs->fs_magic != FS_MAGIC || 401 fs->fs_bsize > MAXBSIZE || fs->fs_bsize < sizeof(struct fs)) { 402 rc = EINVAL; 403 goto out; 404 } 405 406 /* 407 * Calculate indirect block levels. 408 */ 409 { 410 register int mult; 411 register int level; 412 413 mult = 1; 414 for (level = 0; level < NIADDR; level++) { 415 mult *= NINDIR(fs); 416 fp->f_nindir[level] = mult; 417 } 418 } 419 420 inumber = ROOTINO; 421 if ((rc = read_inode(inumber, f)) != 0) 422 goto out; 423 424 cp = path; 425 while (*cp) { 426 427 /* 428 * Remove extra separators 429 */ 430 while (*cp == '/') 431 cp++; 432 if (*cp == '\0') 433 break; 434 435 /* 436 * Check that current node is a directory. 437 */ 438 if ((fp->f_di.di_mode & IFMT) != IFDIR) { 439 rc = ENOTDIR; 440 goto out; 441 } 442 443 /* 444 * Get next component of path name. 445 */ 446 { 447 register int len = 0; 448 449 ncp = cp; 450 while ((c = *cp) != '\0' && c != '/') { 451 if (++len > MAXNAMLEN) { 452 rc = ENOENT; 453 goto out; 454 } 455 cp++; 456 } 457 *cp = '\0'; 458 } 459 460 /* 461 * Look up component in current directory. 462 * Save directory inumber in case we find a 463 * symbolic link. 464 */ 465 parent_inumber = inumber; 466 rc = search_directory(ncp, f, &inumber); 467 *cp = c; 468 if (rc) 469 goto out; 470 471 /* 472 * Open next component. 473 */ 474 if ((rc = read_inode(inumber, f)) != 0) 475 goto out; 476 477 #if 0 478 /* 479 * Check for symbolic link. 480 */ 481 if ((fp->i_mode & IFMT) == IFLNK) { 482 int link_len = fp->f_di.di_size; 483 int len; 484 485 len = strlen(cp) + 1; 486 487 if (fp->f_di.di_size >= MAXPATHLEN - 1 || 488 ++nlinks > MAXSYMLINKS) { 489 rc = ENOENT; 490 goto out; 491 } 492 493 strcpy(&namebuf[link_len], cp); 494 495 if ((fp->i_flags & IC_FASTLINK) != 0) { 496 bcopy(fp->i_symlink, namebuf, (unsigned) link_len); 497 } else { 498 /* 499 * Read file for symbolic link 500 */ 501 char *buf; 502 u_int buf_size; 503 daddr_t disk_block; 504 register struct fs *fs = fp->f_fs; 505 506 (void) block_map(f, (daddr_t)0, &disk_block); 507 rc = device_read(&fp->f_dev, 508 fsbtodb(fs, disk_block), 509 blksize(fs, fp, 0), 510 &buf, &buf_size); 511 if (rc) 512 goto out; 513 514 bcopy((char *)buf, namebuf, (unsigned)link_len); 515 free(buf, buf_size); 516 } 517 518 /* 519 * If relative pathname, restart at parent directory. 520 * If absolute pathname, restart at root. 521 */ 522 cp = namebuf; 523 if (*cp != '/') 524 inumber = parent_inumber; 525 else 526 inumber = (ino_t)ROOTINO; 527 528 if ((rc = read_inode(inumber, fp)) != 0) 529 goto out; 530 } 531 #endif 532 } 533 534 /* 535 * Found terminal component. 536 */ 537 rc = 0; 538 out: 539 if (rc) 540 free(fp, sizeof(struct file)); 541 return (rc); 542 } 543 544 int 545 ufs_close(f) 546 struct open_file *f; 547 { 548 register struct file *fp = (struct file *)f->f_fsdata; 549 int level; 550 551 f->f_fsdata = (void *)0; 552 if (fp == (struct file *)0) 553 return (0); 554 555 for (level = 0; level < NIADDR; level++) { 556 if (fp->f_blk[level]) 557 free(fp->f_blk[level], fp->f_fs->fs_bsize); 558 } 559 if (fp->f_buf) 560 free(fp->f_buf, fp->f_fs->fs_bsize); 561 free(fp->f_fs, SBSIZE); 562 free(fp, sizeof(struct file)); 563 return (0); 564 } 565 566 /* 567 * Copy a portion of a file into kernel memory. 568 * Cross block boundaries when necessary. 569 */ 570 int 571 ufs_read(f, start, size, resid) 572 struct open_file *f; 573 char *start; 574 u_int size; 575 u_int *resid; /* out */ 576 { 577 register struct file *fp = (struct file *)f->f_fsdata; 578 register u_int csize; 579 char *buf; 580 u_int buf_size; 581 int rc = 0; 582 583 while (size != 0) { 584 if (fp->f_seekp >= fp->f_di.di_size) 585 break; 586 587 rc = buf_read_file(f, &buf, &buf_size); 588 if (rc) 589 break; 590 591 csize = size; 592 if (csize > buf_size) 593 csize = buf_size; 594 595 bcopy(buf, start, csize); 596 597 fp->f_seekp += csize; 598 start += csize; 599 size -= csize; 600 } 601 if (resid) 602 *resid = size; 603 return (rc); 604 } 605 606 /* 607 * Not implemented. 608 */ 609 int 610 ufs_write(f, start, size, resid) 611 struct open_file *f; 612 char *start; 613 u_int size; 614 u_int *resid; /* out */ 615 { 616 617 return (EROFS); 618 } 619 620 off_t 621 ufs_seek(f, offset, where) 622 struct open_file *f; 623 off_t offset; 624 int where; 625 { 626 register struct file *fp = (struct file *)f->f_fsdata; 627 628 switch (where) { 629 case SEEK_SET: 630 fp->f_seekp = offset; 631 break; 632 case SEEK_CUR: 633 fp->f_seekp += offset; 634 break; 635 case SEEK_END: 636 fp->f_seekp = fp->f_di.di_size - offset; 637 break; 638 default: 639 return (-1); 640 } 641 return (fp->f_seekp); 642 } 643 644 int 645 ufs_stat(f, sb) 646 struct open_file *f; 647 struct stat *sb; 648 { 649 register struct file *fp = (struct file *)f->f_fsdata; 650 651 /* only important stuff */ 652 sb->st_mode = fp->f_di.di_mode; 653 sb->st_uid = fp->f_di.di_uid; 654 sb->st_gid = fp->f_di.di_gid; 655 sb->st_size = fp->f_di.di_size; 656 return (0); 657 } 658
Indexes created Tue Sep 23 14:10:03 GMT 2025