ufs.c revision 39665
1/* $NetBSD: ufs.c,v 1.20 1998/03/01 07:15:39 ross Exp $ */ 2 3/*- 4 * Copyright (c) 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * The Mach Operating System project at Carnegie-Mellon University. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 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@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 65/* 66 * Stand-alone file reading package. 67 */ 68 69#include <sys/param.h> 70#include <sys/time.h> 71#include <ufs/ufs/dinode.h> 72#include <ufs/ufs/dir.h> 73#include <ufs/ffs/fs.h> 74#include "stand.h" 75#include "string.h" 76 77static int ufs_open(const char *path, struct open_file *f); 78static int ufs_close(struct open_file *f); 79static int ufs_read(struct open_file *f, void *buf, size_t size, size_t *resid); 80static off_t ufs_seek(struct open_file *f, off_t offset, int where); 81static int ufs_stat(struct open_file *f, struct stat *sb); 82 83struct fs_ops ufs_fsops = { 84 "ufs", ufs_open, ufs_close, ufs_read, null_write, ufs_seek, ufs_stat 85}; 86 87/* 88 * In-core open file. 89 */ 90struct file { 91 off_t f_seekp; /* seek pointer */ 92 struct fs *f_fs; /* pointer to super-block */ 93 struct dinode f_di; /* copy of on-disk inode */ 94 int f_nindir[NIADDR]; 95 /* number of blocks mapped by 96 indirect block at level i */ 97 char *f_blk[NIADDR]; /* buffer for indirect block at 98 level i */ 99 size_t f_blksize[NIADDR]; 100 /* size of buffer */ 101 daddr_t f_blkno[NIADDR];/* disk address of block in buffer */ 102 char *f_buf; /* buffer for data block */ 103 size_t f_buf_size; /* size of data block */ 104 daddr_t f_buf_blkno; /* block number of data block */ 105}; 106 107static int read_inode(ino_t, struct open_file *); 108static int block_map(struct open_file *, daddr_t, daddr_t *); 109static int buf_read_file(struct open_file *, char **, size_t *); 110static int search_directory(char *, struct open_file *, ino_t *); 111#ifdef COMPAT_UFS 112static void ffs_oldfscompat(struct fs *); 113#endif 114 115/* 116 * Read a new inode into a file structure. 117 */ 118static int 119read_inode(inumber, f) 120 ino_t inumber; 121 struct open_file *f; 122{ 123 register struct file *fp = (struct file *)f->f_fsdata; 124 register struct fs *fs = fp->f_fs; 125 char *buf; 126 size_t rsize; 127 int rc; 128 129 if (fs == NULL) 130 panic("fs == NULL"); 131 132 /* 133 * Read inode and save it. 134 */ 135 buf = malloc(fs->fs_bsize); 136 twiddle(); 137 rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ, 138 fsbtodb(fs, ino_to_fsba(fs, inumber)), fs->fs_bsize, 139 buf, &rsize); 140 if (rc) 141 goto out; 142 if (rsize != fs->fs_bsize) { 143 rc = EIO; 144 goto out; 145 } 146 147 { 148 register struct dinode *dp; 149 150 dp = (struct dinode *)buf; 151 fp->f_di = dp[ino_to_fsbo(fs, inumber)]; 152 } 153 154 /* 155 * Clear out the old buffers 156 */ 157 { 158 register int level; 159 160 for (level = 0; level < NIADDR; level++) 161 fp->f_blkno[level] = -1; 162 fp->f_buf_blkno = -1; 163 } 164out: 165 free(buf); 166 return (rc); 167} 168 169/* 170 * Given an offset in a file, find the disk block number that 171 * contains that block. 172 */ 173static int 174block_map(f, file_block, disk_block_p) 175 struct open_file *f; 176 daddr_t file_block; 177 daddr_t *disk_block_p; /* out */ 178{ 179 register struct file *fp = (struct file *)f->f_fsdata; 180 register struct fs *fs = fp->f_fs; 181 int level; 182 int idx; 183 daddr_t ind_block_num; 184 daddr_t *ind_p; 185 int rc; 186 187 /* 188 * Index structure of an inode: 189 * 190 * di_db[0..NDADDR-1] hold block numbers for blocks 191 * 0..NDADDR-1 192 * 193 * di_ib[0] index block 0 is the single indirect block 194 * holds block numbers for blocks 195 * NDADDR .. NDADDR + NINDIR(fs)-1 196 * 197 * di_ib[1] index block 1 is the double indirect block 198 * holds block numbers for INDEX blocks for blocks 199 * NDADDR + NINDIR(fs) .. 200 * NDADDR + NINDIR(fs) + NINDIR(fs)**2 - 1 201 * 202 * di_ib[2] index block 2 is the triple indirect block 203 * holds block numbers for double-indirect 204 * blocks for blocks 205 * NDADDR + NINDIR(fs) + NINDIR(fs)**2 .. 206 * NDADDR + NINDIR(fs) + NINDIR(fs)**2 207 * + NINDIR(fs)**3 - 1 208 */ 209 210 if (file_block < NDADDR) { 211 /* Direct block. */ 212 *disk_block_p = fp->f_di.di_db[file_block]; 213 return (0); 214 } 215 216 file_block -= NDADDR; 217 218 /* 219 * nindir[0] = NINDIR 220 * nindir[1] = NINDIR**2 221 * nindir[2] = NINDIR**3 222 * etc 223 */ 224 for (level = 0; level < NIADDR; level++) { 225 if (file_block < fp->f_nindir[level]) 226 break; 227 file_block -= fp->f_nindir[level]; 228 } 229 if (level == NIADDR) { 230 /* Block number too high */ 231 return (EFBIG); 232 } 233 234 ind_block_num = fp->f_di.di_ib[level]; 235 236 for (; level >= 0; level--) { 237 if (ind_block_num == 0) { 238 *disk_block_p = 0; /* missing */ 239 return (0); 240 } 241 242 if (fp->f_blkno[level] != ind_block_num) { 243 if (fp->f_blk[level] == (char *)0) 244 fp->f_blk[level] = 245 malloc(fs->fs_bsize); 246 twiddle(); 247 rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ, 248 fsbtodb(fp->f_fs, ind_block_num), 249 fs->fs_bsize, 250 fp->f_blk[level], 251 &fp->f_blksize[level]); 252 if (rc) 253 return (rc); 254 if (fp->f_blksize[level] != fs->fs_bsize) 255 return (EIO); 256 fp->f_blkno[level] = ind_block_num; 257 } 258 259 ind_p = (daddr_t *)fp->f_blk[level]; 260 261 if (level > 0) { 262 idx = file_block / fp->f_nindir[level - 1]; 263 file_block %= fp->f_nindir[level - 1]; 264 } else 265 idx = file_block; 266 267 ind_block_num = ind_p[idx]; 268 } 269 270 *disk_block_p = ind_block_num; 271 272 return (0); 273} 274 275/* 276 * Read a portion of a file into an internal buffer. Return 277 * the location in the buffer and the amount in the buffer. 278 */ 279static int 280buf_read_file(f, buf_p, size_p) 281 struct open_file *f; 282 char **buf_p; /* out */ 283 size_t *size_p; /* out */ 284{ 285 register struct file *fp = (struct file *)f->f_fsdata; 286 register struct fs *fs = fp->f_fs; 287 long off; 288 register daddr_t file_block; 289 daddr_t disk_block; 290 size_t block_size; 291 int rc; 292 293 off = blkoff(fs, fp->f_seekp); 294 file_block = lblkno(fs, fp->f_seekp); 295 block_size = dblksize(fs, &fp->f_di, file_block); 296 297 if (file_block != fp->f_buf_blkno) { 298 rc = block_map(f, file_block, &disk_block); 299 if (rc) 300 return (rc); 301 302 if (fp->f_buf == (char *)0) 303 fp->f_buf = malloc(fs->fs_bsize); 304 305 if (disk_block == 0) { 306 bzero(fp->f_buf, block_size); 307 fp->f_buf_size = block_size; 308 } else { 309 twiddle(); 310 rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ, 311 fsbtodb(fs, disk_block), 312 block_size, fp->f_buf, &fp->f_buf_size); 313 if (rc) 314 return (rc); 315 } 316 317 fp->f_buf_blkno = file_block; 318 } 319 320 /* 321 * Return address of byte in buffer corresponding to 322 * offset, and size of remainder of buffer after that 323 * byte. 324 */ 325 *buf_p = fp->f_buf + off; 326 *size_p = block_size - off; 327 328 /* 329 * But truncate buffer at end of file. 330 */ 331 if (*size_p > fp->f_di.di_size - fp->f_seekp) 332 *size_p = fp->f_di.di_size - fp->f_seekp; 333 334 return (0); 335} 336 337/* 338 * Search a directory for a name and return its 339 * i_number. 340 */ 341static int 342search_directory(name, f, inumber_p) 343 char *name; 344 struct open_file *f; 345 ino_t *inumber_p; /* out */ 346{ 347 register struct file *fp = (struct file *)f->f_fsdata; 348 register struct direct *dp; 349 struct direct *edp; 350 char *buf; 351 size_t buf_size; 352 int namlen, length; 353 int rc; 354 355 length = strlen(name); 356 357 fp->f_seekp = 0; 358 while (fp->f_seekp < fp->f_di.di_size) { 359 rc = buf_read_file(f, &buf, &buf_size); 360 if (rc) 361 return (rc); 362 363 dp = (struct direct *)buf; 364 edp = (struct direct *)(buf + buf_size); 365 while (dp < edp) { 366 if (dp->d_ino == (ino_t)0) 367 goto next; 368#if BYTE_ORDER == LITTLE_ENDIAN 369 if (fp->f_fs->fs_maxsymlinklen <= 0) 370 namlen = dp->d_type; 371 else 372#endif 373 namlen = dp->d_namlen; 374 if (namlen == length && 375 !strcmp(name, dp->d_name)) { 376 /* found entry */ 377 *inumber_p = dp->d_ino; 378 return (0); 379 } 380 next: 381 dp = (struct direct *)((char *)dp + dp->d_reclen); 382 } 383 fp->f_seekp += buf_size; 384 } 385 return (ENOENT); 386} 387 388/* 389 * Open a file. 390 */ 391static int 392ufs_open(upath, f) 393 const char *upath; 394 struct open_file *f; 395{ 396 register char *cp, *ncp; 397 register int c; 398 ino_t inumber, parent_inumber; 399 struct file *fp; 400 struct fs *fs; 401 int rc; 402 size_t buf_size; 403 int nlinks = 0; 404 char namebuf[MAXPATHLEN+1]; 405 char *buf = NULL; 406 char *path = NULL; 407 408 /* allocate file system specific data structure */ 409 fp = malloc(sizeof(struct file)); 410 bzero(fp, sizeof(struct file)); 411 f->f_fsdata = (void *)fp; 412 413 /* allocate space and read super block */ 414 fs = malloc(SBSIZE); 415 fp->f_fs = fs; 416 twiddle(); 417 rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ, 418 SBLOCK, SBSIZE, (char *)fs, &buf_size); 419 if (rc) 420 goto out; 421 422 if (buf_size != SBSIZE || fs->fs_magic != FS_MAGIC || 423 fs->fs_bsize > MAXBSIZE || fs->fs_bsize < sizeof(struct fs)) { 424 rc = EINVAL; 425 goto out; 426 } 427#ifdef COMPAT_UFS 428 ffs_oldfscompat(fs); 429#endif 430 431 /* 432 * Calculate indirect block levels. 433 */ 434 { 435 register int mult; 436 register int level; 437 438 mult = 1; 439 for (level = 0; level < NIADDR; level++) { 440 mult *= NINDIR(fs); 441 fp->f_nindir[level] = mult; 442 } 443 } 444 445 inumber = ROOTINO; 446 if ((rc = read_inode(inumber, f)) != 0) 447 goto out; 448 449 cp = path = strdup(upath); 450 if (path == NULL) { 451 rc = ENOMEM; 452 goto out; 453 } 454 while (*cp) { 455 456 /* 457 * Remove extra separators 458 */ 459 while (*cp == '/') 460 cp++; 461 if (*cp == '\0') 462 break; 463 464 /* 465 * Check that current node is a directory. 466 */ 467 if ((fp->f_di.di_mode & IFMT) != IFDIR) { 468 rc = ENOTDIR; 469 goto out; 470 } 471 472 /* 473 * Get next component of path name. 474 */ 475 { 476 register int len = 0; 477 478 ncp = cp; 479 while ((c = *cp) != '\0' && c != '/') { 480 if (++len > MAXNAMLEN) { 481 rc = ENOENT; 482 goto out; 483 } 484 cp++; 485 } 486 *cp = '\0'; 487 } 488 489 /* 490 * Look up component in current directory. 491 * Save directory inumber in case we find a 492 * symbolic link. 493 */ 494 parent_inumber = inumber; 495 rc = search_directory(ncp, f, &inumber); 496 *cp = c; 497 if (rc) 498 goto out; 499 500 /* 501 * Open next component. 502 */ 503 if ((rc = read_inode(inumber, f)) != 0) 504 goto out; 505 506 /* 507 * Check for symbolic link. 508 */ 509 if ((fp->f_di.di_mode & IFMT) == IFLNK) { 510 int link_len = fp->f_di.di_size; 511 int len; 512 513 len = strlen(cp); 514 515 if (link_len + len > MAXPATHLEN || 516 ++nlinks > MAXSYMLINKS) { 517 rc = ENOENT; 518 goto out; 519 } 520 521 bcopy(cp, &namebuf[link_len], len + 1); 522 523 if (link_len < fs->fs_maxsymlinklen) { 524 bcopy(fp->f_di.di_shortlink, namebuf, 525 (unsigned) link_len); 526 } else { 527 /* 528 * Read file for symbolic link 529 */ 530 size_t buf_size; 531 daddr_t disk_block; 532 register struct fs *fs = fp->f_fs; 533 534 if (!buf) 535 buf = malloc(fs->fs_bsize); 536 rc = block_map(f, (daddr_t)0, &disk_block); 537 if (rc) 538 goto out; 539 540 twiddle(); 541 rc = (f->f_dev->dv_strategy)(f->f_devdata, 542 F_READ, fsbtodb(fs, disk_block), 543 fs->fs_bsize, buf, &buf_size); 544 if (rc) 545 goto out; 546 547 bcopy((char *)buf, namebuf, (unsigned)link_len); 548 } 549 550 /* 551 * If relative pathname, restart at parent directory. 552 * If absolute pathname, restart at root. 553 */ 554 cp = namebuf; 555 if (*cp != '/') 556 inumber = parent_inumber; 557 else 558 inumber = (ino_t)ROOTINO; 559 560 if ((rc = read_inode(inumber, f)) != 0) 561 goto out; 562 } 563 } 564 565 /* 566 * Found terminal component. 567 */ 568 rc = 0; 569out: 570 if (buf) 571 free(buf); 572 if (path) 573 free(path); 574 if (rc) { 575 if (fp->f_buf) 576 free(fp->f_buf); 577 free(fp->f_fs); 578 free(fp); 579 } 580 return (rc); 581} 582 583static int 584ufs_close(f) 585 struct open_file *f; 586{ 587 register struct file *fp = (struct file *)f->f_fsdata; 588 int level; 589 590 f->f_fsdata = (void *)0; 591 if (fp == (struct file *)0) 592 return (0); 593 594 for (level = 0; level < NIADDR; level++) { 595 if (fp->f_blk[level]) 596 free(fp->f_blk[level]); 597 } 598 if (fp->f_buf) 599 free(fp->f_buf); 600 free(fp->f_fs); 601 free(fp); 602 return (0); 603} 604 605/* 606 * Copy a portion of a file into kernel memory. 607 * Cross block boundaries when necessary. 608 */ 609static int 610ufs_read(f, start, size, resid) 611 struct open_file *f; 612 void *start; 613 size_t size; 614 size_t *resid; /* out */ 615{ 616 register struct file *fp = (struct file *)f->f_fsdata; 617 register size_t csize; 618 char *buf; 619 size_t buf_size; 620 int rc = 0; 621 register char *addr = start; 622 623 while (size != 0) { 624 if (fp->f_seekp >= fp->f_di.di_size) 625 break; 626 627 rc = buf_read_file(f, &buf, &buf_size); 628 if (rc) 629 break; 630 631 csize = size; 632 if (csize > buf_size) 633 csize = buf_size; 634 635 bcopy(buf, addr, csize); 636 637 fp->f_seekp += csize; 638 addr += csize; 639 size -= csize; 640 } 641 if (resid) 642 *resid = size; 643 return (rc); 644} 645 646static off_t 647ufs_seek(f, offset, where) 648 struct open_file *f; 649 off_t offset; 650 int where; 651{ 652 register struct file *fp = (struct file *)f->f_fsdata; 653 654 switch (where) { 655 case SEEK_SET: 656 fp->f_seekp = offset; 657 break; 658 case SEEK_CUR: 659 fp->f_seekp += offset; 660 break; 661 case SEEK_END: 662 fp->f_seekp = fp->f_di.di_size - offset; 663 break; 664 default: 665 return (-1); 666 } 667 return (fp->f_seekp); 668} 669 670static int 671ufs_stat(f, sb) 672 struct open_file *f; 673 struct stat *sb; 674{ 675 register struct file *fp = (struct file *)f->f_fsdata; 676 677 /* only important stuff */ 678 sb->st_mode = fp->f_di.di_mode; 679 sb->st_uid = fp->f_di.di_uid; 680 sb->st_gid = fp->f_di.di_gid; 681 sb->st_size = fp->f_di.di_size; 682 return (0); 683} 684 685#ifdef COMPAT_UFS 686/* 687 * Sanity checks for old file systems. 688 * 689 * XXX - goes away some day. 690 */ 691static void 692ffs_oldfscompat(fs) 693 struct fs *fs; 694{ 695 int i; 696 697 fs->fs_npsect = max(fs->fs_npsect, fs->fs_nsect); /* XXX */ 698 fs->fs_interleave = max(fs->fs_interleave, 1); /* XXX */ 699 if (fs->fs_postblformat == FS_42POSTBLFMT) /* XXX */ 700 fs->fs_nrpos = 8; /* XXX */ 701 if (fs->fs_inodefmt < FS_44INODEFMT) { /* XXX */ 702 quad_t sizepb = fs->fs_bsize; /* XXX */ 703 /* XXX */ 704 fs->fs_maxfilesize = fs->fs_bsize * NDADDR - 1; /* XXX */ 705 for (i = 0; i < NIADDR; i++) { /* XXX */ 706 sizepb *= NINDIR(fs); /* XXX */ 707 fs->fs_maxfilesize += sizepb; /* XXX */ 708 } /* XXX */ 709 fs->fs_qbmask = ~fs->fs_bmask; /* XXX */ 710 fs->fs_qfmask = ~fs->fs_fmask; /* XXX */ 711 } /* XXX */ 712} 713#endif 714