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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 | /* * linux/fs/adfs/dir.c * * Copyright (C) 1997 Russell King */ #include <linux/errno.h> #include <linux/fs.h> #include <linux/adfs_fs.h> #include <linux/sched.h> #include <linux/stat.h> static ssize_t adfs_dirread (struct file *filp, char *buf, size_t siz, loff_t *ppos) { return -EISDIR; } static int adfs_readdir (struct file *, void *, filldir_t); static struct file_operations adfs_dir_operations = { NULL, /* lseek - default */ adfs_dirread, /* read */ NULL, /* write - bad */ adfs_readdir, /* readdir */ NULL, /* select - default */ NULL, /* ioctl */ NULL, /* mmap */ NULL, /* no special open code */ NULL, /* flush */ NULL, /* no special release code */ file_fsync, /* fsync */ NULL, /* fasync */ NULL, /* check_media_change */ NULL /* revalidate */ }; /* * directories can handle most operations... */ struct inode_operations adfs_dir_inode_operations = { &adfs_dir_operations, /* default directory file-ops */ NULL, /* create */ adfs_lookup, /* lookup */ NULL, /* link */ NULL, /* unlink */ NULL, /* symlink */ NULL, /* mkdir */ NULL, /* rmdir */ NULL, /* mknod */ NULL, /* rename */ NULL, /* read link */ NULL, /* follow link */ NULL, /* read page */ NULL, /* write page */ NULL, /* bmap */ NULL, /* truncate */ NULL, /* permission */ NULL /* smap */ }; unsigned int adfs_val (unsigned char *p, int len) { unsigned int val = 0; switch (len) { case 4: val |= p[3] << 24; case 3: val |= p[2] << 16; case 2: val |= p[1] << 8; default: val |= p[0]; } return val; } static unsigned int adfs_filetype (unsigned int load) { if ((load & 0xfff00000) != 0xfff00000) return (unsigned int) -1; return (load >> 8) & 0xfff; } static unsigned int adfs_time (unsigned int load, unsigned int exec) { unsigned int high, low; /* Check for unstamped files. */ if ((load & 0xfff00000) != 0xfff00000) return 0; high = ((load << 24) | (exec >> 8)); low = exec & 255; /* Files dated pre 1970. */ if (high < 0x336e996a) return 0; high -= 0x336e996a; /* Files dated post 2038 ish. */ if (high > 0x31ffffff) return 0x7fffffff; /* 65537 = h256,l1 * (h256 % 100) = 56 h256 / 100 = 2 * 56 << 8 = 14336 2 * 256 = 512 * + l1 = 14337 * / 100 = 143 * + 512 = 655 */ return (((high % 100) << 8) + low) / 100 + (high / 100 << 8); } int adfs_readname (char *buf, char *ptr, int maxlen) { int size = 0; while (*ptr >= ' ' && maxlen--) { switch (*ptr) { case '/': *buf++ = '.'; break; default: *buf++ = *ptr; break; } ptr++; size ++; } *buf = '\0'; return size; } int adfs_dir_read_parent (struct inode *inode, struct buffer_head **bhp) { struct super_block *sb; int i, size; sb = inode->i_sb; size = 2048 >> sb->s_blocksize_bits; for (i = 0; i < size; i++) { int block; block = adfs_parent_bmap (inode, i); if (block) bhp[i] = bread (sb->s_dev, block, sb->s_blocksize); else adfs_error (sb, "adfs_dir_read_parent", "directory %lu with a hole at offset %d", inode->i_ino, i); if (!block || !bhp[i]) { int j; for (j = i - 1; j >= 0; j--) brelse (bhp[j]); return 0; } } return i; } int adfs_dir_read (struct inode *inode, struct buffer_head **bhp) { struct super_block *sb; int i, size; if (!inode || !S_ISDIR(inode->i_mode)) return 0; sb = inode->i_sb; size = inode->i_size >> sb->s_blocksize_bits; for (i = 0; i < size; i++) { int block; block = adfs_bmap (inode, i); if (block) bhp[i] = bread (sb->s_dev, block, sb->s_blocksize); else adfs_error (sb, "adfs_dir_read", "directory %lX,%lX with a hole at offset %d", inode->i_ino, inode->u.adfs_i.file_id, i); if (!block || !bhp[i]) { int j; for (j = i - 1; j >= 0; j--) brelse (bhp[j]); return 0; } } return i; } int adfs_dir_check (struct inode *inode, struct buffer_head **bhp, int buffers, union adfs_dirtail *dtp) { struct adfs_dirheader dh; union adfs_dirtail dt; memcpy (&dh, bhp[0]->b_data, sizeof (dh)); memcpy (&dt, bhp[3]->b_data + 471, sizeof(dt)); if (memcmp (&dh.startmasseq, &dt.new.endmasseq, 5) || (memcmp (&dh.startname, "Nick", 4) && memcmp (&dh.startname, "Hugo", 4))) { adfs_error (inode->i_sb, "adfs_check_dir", "corrupted directory inode %lX,%lX", inode->i_ino, inode->u.adfs_i.file_id); return 1; } if (dtp) *dtp = dt; return 0; } void adfs_dir_free (struct buffer_head **bhp, int buffers) { int i; for (i = buffers - 1; i >= 0; i--) brelse (bhp[i]); } /* convert a disk-based directory entry to a Linux ADFS directory entry */ static inline void adfs_dirent_to_idirent(struct adfs_idir_entry *ide, struct adfs_direntry *de) { ide->name_len = adfs_readname(ide->name, de->dirobname, ADFS_NAME_LEN); ide->file_id = adfs_val(de->dirinddiscadd, 3); ide->size = adfs_val(de->dirlen, 4); ide->mode = de->newdiratts; ide->mtime = adfs_time(adfs_val(de->dirload, 4), adfs_val(de->direxec, 4)); ide->filetype = adfs_filetype(adfs_val(de->dirload, 4)); } int adfs_dir_get (struct super_block *sb, struct buffer_head **bhp, int buffers, int pos, unsigned long parent_object_id, struct adfs_idir_entry *ide) { struct adfs_direntry de; int thissize, buffer, offset; offset = pos & (sb->s_blocksize - 1); buffer = pos >> sb->s_blocksize_bits; if (buffer > buffers) return 0; thissize = sb->s_blocksize - offset; if (thissize > 26) thissize = 26; memcpy (&de, bhp[buffer]->b_data + offset, thissize); if (thissize != 26) memcpy (((char *)&de) + thissize, bhp[buffer + 1]->b_data, 26 - thissize); if (!de.dirobname[0]) return 0; ide->inode_no = adfs_inode_generate (parent_object_id, pos); adfs_dirent_to_idirent(ide, &de); return 1; } int adfs_dir_find_entry (struct super_block *sb, struct buffer_head **bhp, int buffers, unsigned int pos, struct adfs_idir_entry *ide) { struct adfs_direntry de; int offset, buffer, thissize; offset = pos & (sb->s_blocksize - 1); buffer = pos >> sb->s_blocksize_bits; if (buffer > buffers) return 0; thissize = sb->s_blocksize - offset; if (thissize > 26) thissize = 26; memcpy (&de, bhp[buffer]->b_data + offset, thissize); if (thissize != 26) memcpy (((char *)&de) + thissize, bhp[buffer + 1]->b_data, 26 - thissize); if (!de.dirobname[0]) return 0; adfs_dirent_to_idirent(ide, &de); return 1; } static int adfs_readdir (struct file *filp, void *dirent, filldir_t filldir) { struct inode *inode = filp->f_dentry->d_inode; struct super_block *sb; struct buffer_head *bh[4]; union adfs_dirtail dt; unsigned long parent_object_id, dir_object_id; int buffers, pos; sb = inode->i_sb; if (filp->f_pos > ADFS_NUM_DIR_ENTRIES + 2) return -ENOENT; if (!(buffers = adfs_dir_read (inode, bh))) { adfs_error (sb, "adfs_readdir", "unable to read directory"); return -EINVAL; } if (adfs_dir_check (inode, bh, buffers, &dt)) { adfs_dir_free (bh, buffers); return -ENOENT; } parent_object_id = adfs_val (dt.new.dirparent, 3); dir_object_id = adfs_inode_objid (inode); if (filp->f_pos < 2) { if (filp->f_pos < 1) { if (filldir (dirent, ".", 1, 0, inode->i_ino) < 0) return 0; filp->f_pos ++; } if (filldir (dirent, "..", 2, 1, adfs_inode_generate (parent_object_id, 0)) < 0) return 0; filp->f_pos ++; } pos = 5 + (filp->f_pos - 2) * 26; while (filp->f_pos < 79) { struct adfs_idir_entry ide; if (!adfs_dir_get (sb, bh, buffers, pos, dir_object_id, &ide)) break; if (filldir (dirent, ide.name, ide.name_len, filp->f_pos, ide.inode_no) < 0) return 0; filp->f_pos ++; pos += 26; } adfs_dir_free (bh, buffers); return 0; } |