ufs.c revision 1.1
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 1.1 1994/01/26 02:04:01 brezak Exp $ 65 */ 66 67 /* 68 * Stand-alone file reading package. 69 */ 70 71 #include <sys/param.h> 72 #include <sys/time.h> 73 #if 0 /* BSD44 */ 74 #include <ufs/ffs/fs.h> 75 #include <ufs/ufs/dinode.h> 76 #include <ufs/ufs/dir.h> 77 #else 78 #include <ufs/fs.h> 79 #include <ufs/dinode.h> 80 #include <ufs/dir.h> 81 #endif 82 #include "stand.h" 83 84 /* 85 * In-core open file. 86 */ 87 struct file { 88 off_t f_seekp; /* seek pointer */ 89 struct fs *f_fs; /* pointer to super-block */ 90 struct dinode f_di; /* copy of on-disk inode */ 91 int f_nindir[NIADDR]; 92 /* number of blocks mapped by 93 indirect block at level i */ 94 char *f_blk[NIADDR]; /* buffer for indirect block at 95 level i */ 96 u_long f_blksize[NIADDR]; 97 /* size of buffer */ 98 daddr_t f_blkno[NIADDR];/* disk address of block in buffer */ 99 char *f_buf; /* buffer for data block */ 100 u_int f_buf_size; /* size of data block */ 101 daddr_t f_buf_blkno; /* block number of data block */ 102 }; 103 104 /* 105 * Read a new inode into a file structure. 106 */ 107 static int 108 read_inode(inumber, f) 109 ino_t inumber; 110 struct open_file *f; 111 { 112 register struct file *fp = (struct file *)f->f_fsdata; 113 register struct fs *fs = fp->f_fs; 114 char *buf; 115 u_int rsize; 116 int rc; 117 118 /* 119 * Read inode and save it. 120 */ 121 buf = alloc(fs->fs_bsize); 122 rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ, 123 fsbtodb(fs, itod(fs, inumber)), fs->fs_bsize, buf, &rsize); 124 if (rc) 125 goto out; 126 if (rsize != fs->fs_bsize) { 127 rc = EIO; 128 goto out; 129 } 130 131 { 132 register struct dinode *dp; 133 134 dp = (struct dinode *)buf; 135 fp->f_di = dp[itoo(fs, inumber)]; 136 } 137 138 /* 139 * Clear out the old buffers 140 */ 141 { 142 register int level; 143 144 for (level = 0; level < NIADDR; level++) 145 fp->f_blkno[level] = -1; 146 fp->f_buf_blkno = -1; 147 } 148 out: 149 free(buf, fs->fs_bsize); 150 return (0); 151 } 152 153 /* 154 * Given an offset in a file, find the disk block number that 155 * contains that block. 156 */ 157 static int 158 block_map(f, file_block, disk_block_p) 159 struct open_file *f; 160 daddr_t file_block; 161 daddr_t *disk_block_p; /* out */ 162 { 163 register struct file *fp = (struct file *)f->f_fsdata; 164 register struct fs *fs = fp->f_fs; 165 int level; 166 int idx; 167 daddr_t ind_block_num; 168 daddr_t *ind_p; 169 int rc; 170 171 /* 172 * Index structure of an inode: 173 * 174 * di_db[0..NDADDR-1] hold block numbers for blocks 175 * 0..NDADDR-1 176 * 177 * di_ib[0] index block 0 is the single indirect block 178 * holds block numbers for blocks 179 * NDADDR .. NDADDR + NINDIR(fs)-1 180 * 181 * di_ib[1] index block 1 is the double indirect block 182 * holds block numbers for INDEX blocks for blocks 183 * NDADDR + NINDIR(fs) .. 184 * NDADDR + NINDIR(fs) + NINDIR(fs)**2 - 1 185 * 186 * di_ib[2] index block 2 is the triple indirect block 187 * holds block numbers for double-indirect 188 * blocks for blocks 189 * NDADDR + NINDIR(fs) + NINDIR(fs)**2 .. 190 * NDADDR + NINDIR(fs) + NINDIR(fs)**2 191 * + NINDIR(fs)**3 - 1 192 */ 193 194 if (file_block < NDADDR) { 195 /* Direct block. */ 196 *disk_block_p = fp->f_di.di_db[file_block]; 197 return (0); 198 } 199 200 file_block -= NDADDR; 201 202 /* 203 * nindir[0] = NINDIR 204 * nindir[1] = NINDIR**2 205 * nindir[2] = NINDIR**3 206 * etc 207 */ 208 for (level = 0; level < NIADDR; level++) { 209 if (file_block < fp->f_nindir[level]) 210 break; 211 file_block -= fp->f_nindir[level]; 212 } 213 if (level == NIADDR) { 214 /* Block number too high */ 215 return (EFBIG); 216 } 217 218 ind_block_num = fp->f_di.di_ib[level]; 219 220 for (; level >= 0; level--) { 221 if (ind_block_num == 0) { 222 *disk_block_p = 0; /* missing */ 223 return (0); 224 } 225 226 if (fp->f_blkno[level] != ind_block_num) { 227 if (fp->f_blk[level] == (char *)0) 228 fp->f_blk[level] = 229 alloc(fs->fs_bsize); 230 rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ, 231 fsbtodb(fp->f_fs, ind_block_num), 232 fs->fs_bsize, 233 fp->f_blk[level], 234 (u_int *)&fp->f_blksize[level]); 235 if (rc) 236 return (rc); 237 if (fp->f_blksize[level] != fs->fs_bsize) 238 return (EIO); 239 fp->f_blkno[level] = ind_block_num; 240 } 241 242 ind_p = (daddr_t *)fp->f_blk[level]; 243 244 if (level > 0) { 245 idx = file_block / fp->f_nindir[level - 1]; 246 file_block %= fp->f_nindir[level - 1]; 247 } else 248 idx = file_block; 249 250 ind_block_num = ind_p[idx]; 251 } 252 253 *disk_block_p = ind_block_num; 254 255 return (0); 256 } 257 258 /* 259 * Read a portion of a file into an internal buffer. Return 260 * the location in the buffer and the amount in the buffer. 261 */ 262 static int 263 buf_read_file(f, buf_p, size_p) 264 struct open_file *f; 265 char **buf_p; /* out */ 266 u_int *size_p; /* out */ 267 { 268 register struct file *fp = (struct file *)f->f_fsdata; 269 register struct fs *fs = fp->f_fs; 270 long off; 271 register daddr_t file_block; 272 daddr_t disk_block; 273 long block_size; 274 int rc; 275 276 off = blkoff(fs, fp->f_seekp); 277 file_block = lblkno(fs, fp->f_seekp); 278 block_size = dblksize(fs, &fp->f_di, file_block); 279 280 if (file_block != fp->f_buf_blkno) { 281 rc = block_map(f, file_block, &disk_block); 282 if (rc) 283 return (rc); 284 285 if (fp->f_buf == (char *)0) 286 fp->f_buf = alloc(fs->fs_bsize); 287 288 if (disk_block == 0) { 289 bzero(fp->f_buf, block_size); 290 fp->f_buf_size = block_size; 291 } else { 292 rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ, 293 fsbtodb(fs, disk_block), 294 block_size, fp->f_buf, &fp->f_buf_size); 295 if (rc) 296 return (rc); 297 } 298 299 fp->f_buf_blkno = file_block; 300 } 301 302 /* 303 * Return address of byte in buffer corresponding to 304 * offset, and size of remainder of buffer after that 305 * byte. 306 */ 307 *buf_p = fp->f_buf + off; 308 *size_p = block_size - off; 309 310 /* 311 * But truncate buffer at end of file. 312 */ 313 if (*size_p > fp->f_di.di_size - fp->f_seekp) 314 *size_p = fp->f_di.di_size - fp->f_seekp; 315 316 return (0); 317 } 318 319 /* 320 * Search a directory for a name and return its 321 * i_number. 322 */ 323 static int 324 search_directory(name, f, inumber_p) 325 char *name; 326 struct open_file *f; 327 ino_t *inumber_p; /* out */ 328 { 329 register struct file *fp = (struct file *)f->f_fsdata; 330 register struct direct *dp; 331 struct direct *edp; 332 char *buf; 333 u_int buf_size; 334 int namlen, length; 335 int rc; 336 337 length = strlen(name); 338 339 fp->f_seekp = 0; 340 while (fp->f_seekp < fp->f_di.di_size) { 341 rc = buf_read_file(f, &buf, &buf_size); 342 if (rc) 343 return (rc); 344 345 dp = (struct direct *)buf; 346 edp = (struct direct *)(buf + buf_size); 347 while (dp < edp) { 348 if (dp->d_ino == (ino_t)0) 349 goto next; 350 #if 0 351 #if BYTE_ORDER == LITTLE_ENDIAN 352 if (fp->f_fs->fs_maxsymlinklen <= 0) 353 namlen = dp->d_type; 354 else 355 #endif 356 #endif 357 namlen = dp->d_namlen; 358 if (namlen == length && 359 !strcmp(name, dp->d_name)) { 360 /* found entry */ 361 *inumber_p = dp->d_ino; 362 return (0); 363 } 364 next: 365 dp = (struct direct *)((char *)dp + dp->d_reclen); 366 } 367 fp->f_seekp += buf_size; 368 } 369 return (ENOENT); 370 } 371 372 /* 373 * Open a file. 374 */ 375 int 376 ufs_open(path, f) 377 char *path; 378 struct open_file *f; 379 { 380 register char *cp, *ncp; 381 register int c; 382 ino_t inumber, parent_inumber; 383 int nlinks = 0; 384 struct file *fp; 385 struct fs *fs; 386 int rc; 387 u_int buf_size; 388 #if 0 389 char namebuf[MAXPATHLEN+1]; 390 #endif 391 392 /* allocate file system specific data structure */ 393 fp = alloc(sizeof(struct file)); 394 bzero(fp, sizeof(struct file)); 395 f->f_fsdata = (void *)fp; 396 397 /* allocate space and read super block */ 398 fs = alloc(SBSIZE); 399 fp->f_fs = fs; 400 rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ, 401 SBLOCK, SBSIZE, (char *)fs, &buf_size); 402 if (rc) 403 goto out; 404 405 if (buf_size != SBSIZE || fs->fs_magic != FS_MAGIC || 406 fs->fs_bsize > MAXBSIZE || fs->fs_bsize < sizeof(struct fs)) { 407 rc = EINVAL; 408 goto out; 409 } 410 411 /* 412 * Calculate indirect block levels. 413 */ 414 { 415 register int mult; 416 register int level; 417 418 mult = 1; 419 for (level = 0; level < NIADDR; level++) { 420 mult *= NINDIR(fs); 421 fp->f_nindir[level] = mult; 422 } 423 } 424 425 inumber = ROOTINO; 426 if ((rc = read_inode(inumber, f)) != 0) 427 goto out; 428 429 cp = path; 430 while (*cp) { 431 432 /* 433 * Remove extra separators 434 */ 435 while (*cp == '/') 436 cp++; 437 if (*cp == '\0') 438 break; 439 440 /* 441 * Check that current node is a directory. 442 */ 443 if ((fp->f_di.di_mode & IFMT) != IFDIR) { 444 rc = ENOTDIR; 445 goto out; 446 } 447 448 /* 449 * Get next component of path name. 450 */ 451 { 452 register int len = 0; 453 454 ncp = cp; 455 while ((c = *cp) != '\0' && c != '/') { 456 if (++len > MAXNAMLEN) { 457 rc = ENOENT; 458 goto out; 459 } 460 cp++; 461 } 462 *cp = '\0'; 463 } 464 465 /* 466 * Look up component in current directory. 467 * Save directory inumber in case we find a 468 * symbolic link. 469 */ 470 parent_inumber = inumber; 471 rc = search_directory(ncp, f, &inumber); 472 *cp = c; 473 if (rc) 474 goto out; 475 476 /* 477 * Open next component. 478 */ 479 if ((rc = read_inode(inumber, f)) != 0) 480 goto out; 481 482 #if 0 483 /* 484 * Check for symbolic link. 485 */ 486 if ((fp->i_mode & IFMT) == IFLNK) { 487 int link_len = fp->f_di.di_size; 488 int len; 489 490 len = strlen(cp) + 1; 491 492 if (fp->f_di.di_size >= MAXPATHLEN - 1 || 493 ++nlinks > MAXSYMLINKS) { 494 rc = ENOENT; 495 goto out; 496 } 497 498 strcpy(&namebuf[link_len], cp); 499 500 if ((fp->i_flags & IC_FASTLINK) != 0) { 501 bcopy(fp->i_symlink, namebuf, (unsigned) link_len); 502 } else { 503 /* 504 * Read file for symbolic link 505 */ 506 char *buf; 507 u_int buf_size; 508 daddr_t disk_block; 509 register struct fs *fs = fp->f_fs; 510 511 (void) block_map(f, (daddr_t)0, &disk_block); 512 rc = device_read(&fp->f_dev, 513 fsbtodb(fs, disk_block), 514 blksize(fs, fp, 0), 515 &buf, &buf_size); 516 if (rc) 517 goto out; 518 519 bcopy((char *)buf, namebuf, (unsigned)link_len); 520 free(buf, buf_size); 521 } 522 523 /* 524 * If relative pathname, restart at parent directory. 525 * If absolute pathname, restart at root. 526 */ 527 cp = namebuf; 528 if (*cp != '/') 529 inumber = parent_inumber; 530 else 531 inumber = (ino_t)ROOTINO; 532 533 if ((rc = read_inode(inumber, fp)) != 0) 534 goto out; 535 } 536 #endif 537 } 538 539 /* 540 * Found terminal component. 541 */ 542 rc = 0; 543 out: 544 if (rc) 545 free(fp, sizeof(struct file)); 546 return (rc); 547 } 548 549 int 550 ufs_close(f) 551 struct open_file *f; 552 { 553 register struct file *fp = (struct file *)f->f_fsdata; 554 int level; 555 556 f->f_fsdata = (void *)0; 557 if (fp == (struct file *)0) 558 return (0); 559 560 for (level = 0; level < NIADDR; level++) { 561 if (fp->f_blk[level]) 562 free(fp->f_blk[level], fp->f_fs->fs_bsize); 563 } 564 if (fp->f_buf) 565 free(fp->f_buf, fp->f_fs->fs_bsize); 566 free(fp->f_fs, SBSIZE); 567 free(fp, sizeof(struct file)); 568 return (0); 569 } 570 571 /* 572 * Copy a portion of a file into kernel memory. 573 * Cross block boundaries when necessary. 574 */ 575 int 576 ufs_read(f, start, size, resid) 577 struct open_file *f; 578 char *start; 579 u_int size; 580 u_int *resid; /* out */ 581 { 582 register struct file *fp = (struct file *)f->f_fsdata; 583 register u_int csize; 584 char *buf; 585 u_int buf_size; 586 int rc = 0; 587 588 while (size != 0) { 589 if (fp->f_seekp >= fp->f_di.di_size) 590 break; 591 592 rc = buf_read_file(f, &buf, &buf_size); 593 if (rc) 594 break; 595 596 csize = size; 597 if (csize > buf_size) 598 csize = buf_size; 599 600 bcopy(buf, start, csize); 601 602 fp->f_seekp += csize; 603 start += csize; 604 size -= csize; 605 } 606 if (resid) 607 *resid = size; 608 return (rc); 609 } 610 611 /* 612 * Not implemented. 613 */ 614 int 615 ufs_write(f, start, size, resid) 616 struct open_file *f; 617 char *start; 618 u_int size; 619 u_int *resid; /* out */ 620 { 621 622 return (EROFS); 623 } 624 625 off_t 626 ufs_seek(f, offset, where) 627 struct open_file *f; 628 off_t offset; 629 int where; 630 { 631 register struct file *fp = (struct file *)f->f_fsdata; 632 633 switch (where) { 634 case SEEK_SET: 635 fp->f_seekp = offset; 636 break; 637 case SEEK_CUR: 638 fp->f_seekp += offset; 639 break; 640 case SEEK_END: 641 fp->f_seekp = fp->f_di.di_size - offset; 642 break; 643 default: 644 return (-1); 645 } 646 return (fp->f_seekp); 647 } 648 649 int 650 ufs_stat(f, sb) 651 struct open_file *f; 652 struct stat *sb; 653 { 654 register struct file *fp = (struct file *)f->f_fsdata; 655 656 /* only important stuff */ 657 sb->st_mode = fp->f_di.di_mode; 658 sb->st_uid = fp->f_di.di_uid; 659 sb->st_gid = fp->f_di.di_gid; 660 sb->st_size = fp->f_di.di_size; 661 return (0); 662 } 663
Indexes created Wed Sep 24 05:09:52 GMT 2025