ffs.c revision 1.2
1 /* $NetBSD: ffs.c,v 1.2 2002/04/30 14:21:17 lukem Exp $ */ 2 3 /*- 4 * Copyright (c) 2002 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Matt Fredette. 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 NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 #include <sys/cdefs.h> 40 #if defined(__RCSID) && !defined(__lint) 41 __RCSID("$NetBSD: ffs.c,v 1.2 2002/04/30 14:21:17 lukem Exp $"); 42 #endif /* !__lint */ 43 44 #include <sys/param.h> 45 #include <sys/mount.h> 46 47 #include <assert.h> 48 #include <err.h> 49 #include <errno.h> 50 #include <fcntl.h> 51 #include <stdarg.h> 52 #include <stdio.h> 53 #include <stdlib.h> 54 #include <string.h> 55 #include <unistd.h> 56 57 #include "installboot.h" 58 59 #undef DIRBLKSIZ 60 61 #include <ufs/ufs/dinode.h> 62 #include <ufs/ufs/dir.h> 63 #include <ufs/ffs/fs.h> 64 #include <ufs/ffs/ffs_extern.h> 65 #include <ufs/ufs/ufs_bswap.h> 66 67 /* This reads a disk block from the filesystem. */ 68 static int 69 ffs_read_disk_block(ib_params *params, uint32_t blkno, int size, char *blk) 70 { 71 int rv; 72 73 assert(params != NULL); 74 assert(blk != NULL); 75 assert(params->filesystem != NULL); 76 assert(params->fsfd != -1); 77 assert(blkno > 0); 78 assert(size > 0); 79 assert(blk != NULL); 80 81 rv = pread(params->fsfd, blk, size, blkno * DEV_BSIZE); 82 if (rv == -1) { 83 warn("Reading block %d in `%s'", blkno, params->filesystem); 84 return (0); 85 } else if (rv != size) { 86 warnx("Reading block %d in `%s': short read", blkno, 87 params->filesystem); 88 return (0); 89 } 90 91 return (1); 92 } 93 94 /* 95 * This iterates over the data blocks belonging to an inode, 96 * making a callback each iteration with the disk block number 97 * and the size. 98 */ 99 static int 100 ffs_find_disk_blocks(ib_params *params, uint32_t ino, 101 int (*callback)(ib_params *, void *, uint32_t, uint32_t, int), 102 void *state) 103 { 104 char sbbuf[SBSIZE]; 105 struct fs *fs; 106 int needswap; 107 char inodebuf[MAXBSIZE]; 108 struct dinode *inode; 109 int level_i; 110 ufs_daddr_t blk, lblk, nblk; 111 int rv; 112 #define LEVELS 4 113 struct { 114 ufs_daddr_t *blknums; 115 unsigned long blkcount; 116 char diskbuf[MAXBSIZE]; 117 } level[LEVELS]; 118 119 assert(params != NULL); 120 assert(callback != NULL); 121 assert(state != NULL); 122 123 /* Read the superblock. */ 124 if (! ffs_read_disk_block(params, SBLOCK, SBSIZE, sbbuf)) 125 return (0); 126 fs = (struct fs *)sbbuf; 127 needswap = 0; 128 if (fs->fs_magic == htole32(FS_MAGIC)) { 129 #if BYTE_ORDER == BIG_ENDIAN 130 needswap = 1; 131 #endif 132 } else if (fs->fs_magic == htobe32(FS_MAGIC)) { 133 #if BYTE_ORDER == LITTLE_ENDIAN 134 needswap = 1; 135 #endif 136 } else 137 return (0); 138 if (needswap) 139 ffs_sb_swap(fs, fs); 140 141 /* Sanity check the superblock. */ 142 if (fs->fs_magic != FS_MAGIC) { 143 warnx("Bad superblock magic number in `%s'", 144 params->filesystem); 145 return (0); 146 } 147 if (fs->fs_inopb <= 0) { 148 warnx("Bad inopb %d in superblock in `%s'", 149 fs->fs_inopb, params->filesystem); 150 return (0); 151 } 152 153 /* Read the inode. */ 154 if (! ffs_read_disk_block(params, fsbtodb(fs, ino_to_fsba(fs, ino)), 155 fs->fs_bsize, inodebuf)) 156 return (0); 157 inode = (struct dinode *)inodebuf; 158 inode += ino_to_fsbo(fs, ino); 159 if (needswap) 160 ffs_dinode_swap(inode, inode); 161 162 /* Get the block count and initialize for our block walk. */ 163 nblk = howmany(inode->di_size, fs->fs_bsize); 164 lblk = 0; 165 level_i = 0; 166 level[0].blknums = &inode->di_db[0]; 167 level[0].blkcount = NDADDR; 168 level[1].blknums = &inode->di_ib[0]; 169 level[1].blkcount = 1; 170 level[2].blknums = &inode->di_ib[1]; 171 level[2].blkcount = 1; 172 level[3].blknums = &inode->di_ib[2]; 173 level[3].blkcount = 1; 174 175 /* Walk the data blocks. */ 176 while (nblk > 0) { 177 178 /* 179 * If there are no more blocks at this indirection 180 * level, move up one indirection level and loop. 181 */ 182 if (level[level_i].blkcount == 0) { 183 if (++level_i == LEVELS) 184 break; 185 continue; 186 } 187 188 /* Get the next block at this level. */ 189 blk = *(level[level_i].blknums++); 190 level[level_i].blkcount--; 191 if (needswap) 192 blk = bswap32(blk); 193 194 #if 0 195 fprintf(stderr, "ino %lu blk %lu level %d\n", ino, blk, 196 level_i); 197 #endif 198 199 /* 200 * If we're not at the direct level, descend one 201 * level, read in that level's new block list, 202 * and loop. 203 */ 204 if (level_i > 0) { 205 level_i--; 206 if (blk == 0) 207 memset(level[level_i].diskbuf, 0, MAXBSIZE); 208 else if (! ffs_read_disk_block(params, 209 fsbtodb(fs, blk), 210 fs->fs_bsize, level[level_i].diskbuf)) 211 return (0); 212 level[level_i].blknums = 213 (ufs_daddr_t *)level[level_i].diskbuf; 214 level[level_i].blkcount = NINDIR(fs); 215 continue; 216 } 217 218 /* blk is the next direct level block. */ 219 #if 0 220 fprintf(stderr, "ino %lu db %lu blksize %lu\n", ino, 221 fsbtodb(fs, blk), dblksize(fs, inode, lblk)); 222 #endif 223 rv = (*callback)(params, state, 224 fsbtodb(fs, blk), dblksize(fs, inode, lblk), needswap); 225 lblk++; 226 nblk--; 227 if (rv != 1) 228 return (rv); 229 } 230 231 if (nblk != 0) { 232 warnx("Inode %d in `%s' ran out of blocks?", ino, 233 params->filesystem); 234 return (0); 235 } 236 237 return (1); 238 } 239 240 /* 241 * This callback reads a block of the root directory, 242 * searches for an entry for the secondary bootstrap, 243 * and saves the inode number if one is found. 244 */ 245 static int 246 ffs_findstage2_ino(ib_params *params, void *_ino, 247 uint32_t blk, uint32_t blksize, int needswap) 248 { 249 char dirbuf[MAXBSIZE]; 250 struct direct *de, *ede; 251 uint32_t ino; 252 253 assert(params != NULL); 254 assert(_ino != NULL); 255 256 /* Skip directory holes. */ 257 if (blk == 0) 258 return (1); 259 260 /* Read the directory block. */ 261 if (! ffs_read_disk_block(params, blk, blksize, dirbuf)) 262 return (0); 263 264 /* Loop over the directory entries. */ 265 de = (struct direct *)&dirbuf[0]; 266 ede = (struct direct *)&dirbuf[blksize]; 267 while (de < ede) { 268 ino = de->d_ino; 269 if (needswap) { 270 ino = bswap32(ino); 271 de->d_reclen = bswap16(de->d_reclen); 272 } 273 if (ino != 0 && strcmp(de->d_name, params->stage2) == 0) { 274 *((uint32_t *)_ino) = ino; 275 return (2); 276 } 277 de = (struct direct *)((char *)de + de->d_reclen); 278 } 279 280 return (1); 281 } 282 283 struct findblks_state { 284 uint32_t maxblk; 285 uint32_t nblk; 286 ib_block *blocks; 287 }; 288 289 /* This callback records the blocks of the secondary bootstrap. */ 290 static int 291 ffs_findstage2_blocks(ib_params *params, void *_state, 292 uint32_t blk, uint32_t blksize, int needswap) 293 { 294 struct findblks_state *state = _state; 295 296 assert(params != NULL); 297 assert(_state != NULL); 298 299 if (state->nblk == state->maxblk) { 300 warnx("Secondary bootstrap `%s' has too many blocks " \ 301 "(max %d)\n", params->stage2, state->maxblk); 302 return (0); 303 } 304 state->blocks[state->nblk].block = blk; 305 state->blocks[state->nblk].blocksize = blksize; 306 state->nblk++; 307 return (1); 308 } 309 310 /* publically visible functions */ 311 312 int 313 ffs_match(ib_params *params) 314 { 315 char sbbuf[SBSIZE]; 316 struct fs *fs; 317 318 assert(params != NULL); 319 assert(params->stage2 != NULL); 320 321 /* Read and check the superblock. */ 322 if (! ffs_read_disk_block(params, SBLOCK, SBSIZE, sbbuf)) 323 return (0); 324 fs = (struct fs *)sbbuf; 325 if (fs->fs_magic == htole32(FS_MAGIC) || 326 fs->fs_magic == htobe32(FS_MAGIC)) 327 return (1); 328 329 return (0); 330 } 331 332 int 333 ffs_findstage2(ib_params *params, uint32_t *maxblk, ib_block *blocks) 334 { 335 int rv; 336 uint32_t ino; 337 struct findblks_state state; 338 339 assert(params != NULL); 340 assert(params->stage2 != NULL); 341 assert(maxblk != NULL); 342 assert(blocks != NULL); 343 344 /* The secondary bootstrap must be clearly in /. */ 345 if (params->stage2[0] == '/') 346 params->stage2++; 347 if (strchr(params->stage2, '/') != NULL) { 348 warnx("The secondary bootstrap `%s' must be in /", 349 params->stage2); 350 return (0); 351 } 352 353 /* Get the inode number of the secondary bootstrap. */ 354 rv = ffs_find_disk_blocks(params, ROOTINO, ffs_findstage2_ino, &ino); 355 if (rv != 2) 356 return (0); 357 358 /* Record the disk blocks of the secondary bootstrap. */ 359 state.maxblk = *maxblk; 360 state.nblk = 0; 361 state.blocks = blocks; 362 rv = ffs_find_disk_blocks(params, ino, ffs_findstage2_blocks, &state); 363 if (! rv) 364 return (0); 365 366 *maxblk = state.nblk; 367 return (1); 368 } 369
Indexes created Fri Sep 26 08:10:20 GMT 2025