fs/grubfs/fsys_ffs.c

   1 /*
   2  *  GRUB  --  GRand Unified Bootloader
   3  *  Copyright (C) 2000, 2001  Free Software Foundation, Inc.
   4  *
   5  *  This program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation; either version 2 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program; if not, write to the Free Software
  17  *  Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  18  *  MA 02110-1301, USA.
  19  */
  20
  21 /*
  22  * Elements of this file were originally from the FreeBSD "biosboot"
  23  * bootloader file "disk.c" dated 4/12/95.
  24  *
  25  * The license and header comments from that file are included here.
  26  */
  27
  28 /*
  29  * Mach Operating System
  30  * Copyright (c) 1992, 1991 Carnegie Mellon University
  31  * All Rights Reserved.
  32  *
  33  * Permission to use, copy, modify and distribute this software and its
  34  * documentation is hereby granted, provided that both the copyright
  35  * notice and this permission notice appear in all copies of the
  36  * software, derivative works or modified versions, and any portions
  37  * thereof, and that both notices appear in supporting documentation.
  38  *
  39  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  40  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  41  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  42  *
  43  * Carnegie Mellon requests users of this software to return to
  44  *
  45  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  46  *  School of Computer Science
  47  *  Carnegie Mellon University
  48  *  Pittsburgh PA 15213-3890
  49  *
  50  * any improvements or extensions that they make and grant Carnegie Mellon
  51  * the rights to redistribute these changes.
  52  *
  53  *      from: Mach, Revision 2.2  92/04/04  11:35:49  rpd
  54  *      $Id: fsys_ffs.c,v 1.10 2001/11/12 06:57:29 okuji Exp $
  55  */
  56
  57 #ifdef FSYS_FFS
  58
  59 #include "shared.h"
  60
  61 #include "filesys.h"
  62
  63 #include "defs.h"
  64 #include "disk_inode.h"
  65 #include "disk_inode_ffs.h"
  66 #include "dir.h"
  67 #include "fs.h"
  68
  69 /* used for filesystem map blocks */
  70 static int mapblock;
  71 static int mapblock_offset;
  72 static int mapblock_bsize;
  73
  74 /* pointer to superblock */
  75 #define SUPERBLOCK ((struct fs *) ( FSYS_BUF + 8192 ))
  76 #define INODE ((struct icommon *) ( FSYS_BUF + 16384 ))
  77 #define MAPBUF ( FSYS_BUF + 24576 )
  78 #define MAPBUF_LEN 8192
  79
  80
  81 int
  82 ffs_mount (void)
  83 {
  84   int retval = 1;
  85
  86   if ((((current_drive & 0x80) || (current_slice != 0))
  87        && ! IS_PC_SLICE_TYPE_BSD_WITH_FS (current_slice, FS_BSDFFS))
  88       || part_length < (SBLOCK + (SBSIZE / DEV_BSIZE))
  89       || !devread (SBLOCK, 0, SBSIZE, (char *) SUPERBLOCK)
  90       || SUPERBLOCK->fs_magic != FS_MAGIC)
  91     retval = 0;
  92
  93   mapblock = -1;
  94   mapblock_offset = -1;
  95
  96   return retval;
  97 }
  98
  99 static int
 100 block_map (int file_block)
 101 {
 102   int bnum, offset, bsize;
 103
 104   if (file_block < NDADDR)
 105     return (INODE->i_db[file_block]);
 106
 107   /* If the blockmap loaded does not include FILE_BLOCK,
 108      load a new blockmap.  */
 109   if ((bnum = fsbtodb (SUPERBLOCK, INODE->i_ib[0])) != mapblock
 110       || (mapblock_offset <= bnum && bnum <= mapblock_offset + mapblock_bsize))
 111     {
 112       if (MAPBUF_LEN < SUPERBLOCK->fs_bsize)
 113         {
 114           offset = ((file_block - NDADDR) % NINDIR (SUPERBLOCK));
 115           bsize = MAPBUF_LEN;
 116
 117           if (offset + MAPBUF_LEN > SUPERBLOCK->fs_bsize)
 118             offset = (SUPERBLOCK->fs_bsize - MAPBUF_LEN) / sizeof (int);
 119         }
 120       else
 121         {
 122           bsize = SUPERBLOCK->fs_bsize;
 123           offset = 0;
 124         }
 125
 126       if (! devread (bnum, offset * sizeof (int), bsize, (char *) MAPBUF))
 127         {
 128           mapblock = -1;
 129           mapblock_bsize = -1;
 130           mapblock_offset = -1;
 131           errnum = ERR_FSYS_CORRUPT;
 132           return -1;
 133         }
 134
 135       mapblock = bnum;
 136       mapblock_bsize = bsize;
 137       mapblock_offset = offset;
 138     }
 139
 140   return (((int *) MAPBUF)[((file_block - NDADDR) % NINDIR (SUPERBLOCK))
 141                           - mapblock_offset]);
 142 }
 143
 144
 145 int
 146 ffs_read (char *buf, int len)
 147 {
 148   int logno, off, size, map, ret = 0;
 149
 150   while (len && !errnum)
 151     {
 152       off = blkoff (SUPERBLOCK, filepos);
 153       logno = lblkno (SUPERBLOCK, filepos);
 154       size = blksize (SUPERBLOCK, INODE, logno);
 155
 156       if ((map = block_map (logno)) < 0)
 157         break;
 158
 159       size -= off;
 160
 161       if (size > len)
 162         size = len;
 163
 164       disk_read_func = disk_read_hook;
 165
 166       devread (fsbtodb (SUPERBLOCK, map), off, size, buf);
 167
 168       disk_read_func = NULL;
 169
 170       buf += size;
 171       len -= size;
 172       filepos += size;
 173       ret += size;
 174     }
 175
 176   if (errnum)
 177     ret = 0;
 178
 179   return ret;
 180 }
 181
 182
 183 int
 184 ffs_dir (char *dirname)
 185 {
 186   char *rest, ch;
 187   int block, off, loc, map, ino = ROOTINO;
 188   struct direct *dp;
 189
 190 /* main loop to find destination inode */
 191 loop:
 192
 193   /* load current inode (defaults to the root inode) */
 194
 195         if (!devread (fsbtodb (SUPERBLOCK, itod (SUPERBLOCK, ino)),
 196                                                                 ino % (SUPERBLOCK->fs_inopb) * sizeof (struct dinode),
 197                                                                 sizeof (struct dinode), (char *) INODE))
 198                         return 0;                       /* XXX what return value? */
 199
 200   /* if we have a real file (and we're not just printing possibilities),
 201      then this is where we want to exit */
 202
 203   if (!*dirname || isspace (*dirname))
 204     {
 205       if ((INODE->i_mode & IFMT) != IFREG)
 206         {
 207           errnum = ERR_BAD_FILETYPE;
 208           return 0;
 209         }
 210
 211       filemax = INODE->i_size;
 212
 213       /* incomplete implementation requires this! */
 214       fsmax = (NDADDR + NINDIR (SUPERBLOCK)) * SUPERBLOCK->fs_bsize;
 215       return 1;
 216     }
 217
 218   /* continue with file/directory name interpretation */
 219
 220   while (*dirname == '/')
 221     dirname++;
 222
 223   if (!(INODE->i_size) || ((INODE->i_mode & IFMT) != IFDIR))
 224     {
 225       errnum = ERR_BAD_FILETYPE;
 226       return 0;
 227     }
 228
 229   for (rest = dirname; (ch = *rest) && !isspace (ch) && ch != '/'; rest++);
 230
 231   *rest = 0;
 232   loc = 0;
 233
 234   /* loop for reading a the entries in a directory */
 235
 236   do
 237     {
 238       if (loc >= INODE->i_size)
 239         {
 240 #if 0
 241           putchar ('\n');
 242 #endif
 243
 244           if (print_possibilities < 0)
 245             return 1;
 246
 247           errnum = ERR_FILE_NOT_FOUND;
 248           *rest = ch;
 249           return 0;
 250         }
 251
 252       if (!(off = blkoff (SUPERBLOCK, loc)))
 253         {
 254           block = lblkno (SUPERBLOCK, loc);
 255
 256           if ((map = block_map (block)) < 0
 257               || !devread (fsbtodb (SUPERBLOCK, map), 0,
 258                            blksize (SUPERBLOCK, INODE, block),
 259                            (char *) FSYS_BUF))
 260             {
 261               errnum = ERR_FSYS_CORRUPT;
 262               *rest = ch;
 263               return 0;
 264             }
 265         }
 266
 267       dp = (struct direct *) (FSYS_BUF + off);
 268       loc += dp->d_reclen;
 269
 270 #ifndef STAGE1_5
 271       if (dp->d_ino && print_possibilities && ch != '/'
 272           && (!*dirname || substring (dirname, dp->d_name) <= 0))
 273         {
 274           if (print_possibilities > 0)
 275             print_possibilities = -print_possibilities;
 276
 277           print_a_completion (dp->d_name);
 278         }
 279 #endif /* STAGE1_5 */
 280     }
 281   while (!dp->d_ino || (substring (dirname, dp->d_name) != 0
 282                         || (print_possibilities && ch != '/')));
 283
 284   /* only get here if we have a matching directory entry */
 285
 286   ino = dp->d_ino;
 287   *(dirname = rest) = ch;
 288
 289   /* go back to main loop at top of function */
 290   goto loop;
 291 }
 292
 293 int
 294 ffs_embed (int *start_sector, int needed_sectors)
 295 {
 296   /* XXX: I don't know if this is really correct. Someone who is
 297      familiar with BSD should check for this.  */
 298   if (needed_sectors > 14)
 299     return 0;
 300
 301   *start_sector = 1;
 302 #if 1
 303   /* FIXME: Disable the embedding in FFS until someone checks if
 304      the code above is correct.  */
 305   return 0;
 306 #else
 307   return 1;
 308 #endif
 309 }
 310
 311 #endif /* FSYS_FFS */