fs/isofs/rock.c

/* */
This source file includes following definitions.
find_rock_ridge_relocation
get_rock_ridge_filename
parse_rock_ridge_inode
get_rock_ridge_symlink
   1 /*
   2  *  linux/fs/isofs/rock.c
   3  *
   4  *  (C) 1992, 1993  Eric Youngdale
   5  *
   6  *  Rock Ridge Extensions to iso9660
   7  */
   8 #include <linux/config.h>
   9 #include <linux/stat.h>
  10 #include <linux/sched.h>
  11 #include <linux/iso_fs.h>
  12 #include <linux/string.h>
  13 #include <linux/mm.h>
  14 #include <linux/malloc.h>
  15 
  16 #include "rock.h"
  17 
  18 /* These functions are designed to read the system areas of a directory record
  19  * and extract relevant information.  There are different functions provided
  20  * depending upon what information we need at the time.  One function fills
  21  * out an inode structure, a second one extracts a filename, a third one
  22  * returns a symbolic link name, and a fourth one returns the extent number
  23  * for the file. */
  24 
  25 #define SIG(A,B) ((A << 8) | B)
  26 
  27 
  28 /* This is a way of ensuring that we have something in the system
  29    use fields that is compatible with Rock Ridge */
  30 #define CHECK_SP(FAIL)                          \
  31       if(rr->u.SP.magic[0] != 0xbe) FAIL;       \
  32       if(rr->u.SP.magic[1] != 0xef) FAIL;
  33 
  34 /* We define a series of macros because each function must do exactly the
  35    same thing in certain places.  We use the macros to ensure that everything
  36    is done correctly */
  37 
  38 #define CONTINUE_DECLS \
  39   int cont_extent = 0, cont_offset = 0, cont_size = 0;   \
  40   void * buffer = 0
  41 
  42 #define CHECK_CE                                \
  43       {cont_extent = isonum_733(rr->u.CE.extent); \
  44       cont_offset = isonum_733(rr->u.CE.offset); \
  45       cont_size = isonum_733(rr->u.CE.size);}
  46 
  47 #define SETUP_ROCK_RIDGE(DE,CHR,LEN)                            \
  48   {LEN= sizeof(struct iso_directory_record) + DE->name_len[0];  \
  49   if(LEN & 1) LEN++;                                            \
  50   CHR = ((unsigned char *) DE) + LEN;                           \
  51   LEN = *((unsigned char *) DE) - LEN;}
  52 
  53 #define MAYBE_CONTINUE(LABEL,DEV) \
  54   {if (buffer) kfree(buffer); \
  55   if (cont_extent){ \
  56     int block, offset, offset1; \
  57     struct buffer_head * bh; \
  58     buffer = kmalloc(cont_size,GFP_KERNEL); \
  59     block = cont_extent; \
  60     offset = cont_offset; \
  61     offset1 = 0; \
  62     if(ISOFS_BUFFER_SIZE(DEV) == 1024) {     \
  63       block <<= 1;    \
  64       if (offset >= 1024) block++; \
  65       offset &= 1023; \
  66       if(offset + cont_size >= 1024) { \
  67           bh = bread(DEV->i_dev, block++, ISOFS_BUFFER_SIZE(DEV)); \
  68           if(!bh) {printk("Unable to read continuation Rock Ridge record\n"); \
  69                      kfree(buffer); \
  70                      buffer = NULL; } else { \
  71             memcpy(buffer, bh->b_data + offset, 1024 - offset); \
  72             brelse(bh); \
  73             offset1 = 1024 - offset; \
  74             offset = 0;} \
  75       }  \
  76     };     \
  77     if(buffer) { \
  78       bh = bread(DEV->i_dev, block, ISOFS_BUFFER_SIZE(DEV)); \
  79       if(bh){       \
  80         memcpy(buffer + offset1, bh->b_data + offset, cont_size - offset1); \
  81         brelse(bh); \
  82         chr = (unsigned char *) buffer; \
  83         len = cont_size; \
  84         cont_extent = 0; \
  85         cont_size = 0; \
  86         cont_offset = 0; \
  87         goto LABEL; \
  88       };    \
  89     } \
  90     printk("Unable to read rock-ridge attributes\n");    \
  91   }}
  92 
  93 /* This is the inner layer of the get filename routine, and is called
  94    for each system area and continuation record related to the file */
  95 
  96 int find_rock_ridge_relocation(struct iso_directory_record * de, 
     /*  */
  97                                struct inode * inode) {
  98   int flag;
  99   int len;
 100   int retval;
 101   unsigned char * chr;
 102   CONTINUE_DECLS;
 103   flag = 0;
 104   
 105   /* If this is a '..' then we are looking for the parent, otherwise we
 106      are looking for the child */
 107   
 108   if (de->name[0]==1 && de->name_len[0]==1) flag = 1;
 109   /* Return value if we do not find appropriate record. */
 110   retval = isonum_733 (de->extent);
 111   
 112   if (!inode->i_sb->u.isofs_sb.s_rock) return retval;
 113 
 114   SETUP_ROCK_RIDGE(de, chr, len);
 115  repeat:
 116   {
 117     int rrflag, sig;
 118     struct rock_ridge * rr;
 119     
 120     while (len > 1){ /* There may be one byte for padding somewhere */
 121       rr = (struct rock_ridge *) chr;
 122       if (rr->len == 0) goto out; /* Something got screwed up here */
 123       sig = (chr[0] << 8) + chr[1];
 124       chr += rr->len; 
 125       len -= rr->len;
 126 
 127       switch(sig){
 128       case SIG('R','R'):
 129         rrflag = rr->u.RR.flags[0];
 130         if (flag && !(rrflag & RR_PL)) goto out;
 131         if (!flag && !(rrflag & RR_CL)) goto out;
 132         break;
 133       case SIG('S','P'):
 134         CHECK_SP(goto out);
 135         break;
 136       case SIG('C','L'):
 137 #ifdef DEBUG
 138         printk("RR: CL\n");
 139 #endif
 140         if (flag == 0) {
 141           retval = isonum_733(rr->u.CL.location);
 142           goto out;
 143         };
 144         break;
 145       case SIG('P','L'):
 146 #ifdef DEBUG
 147         printk("RR: PL\n");
 148 #endif
 149         if (flag != 0) {
 150           retval = isonum_733(rr->u.PL.location);
 151           goto out;
 152         };
 153         break;
 154       case SIG('C','E'):
 155         CHECK_CE; /* This tells is if there is a continuation record */
 156         break;
 157       default:
 158         break;
 159       }
 160     };
 161   };
 162   MAYBE_CONTINUE(repeat, inode);
 163   return retval;
 164  out:
 165   if(buffer) kfree(buffer);
 166   return retval;
 167 }
 168 
 169 int get_rock_ridge_filename(struct iso_directory_record * de,
     /*  */
 170                            char ** name, int * namlen, struct inode * inode)
 171 {
 172   int len;
 173   unsigned char * chr;
 174   CONTINUE_DECLS;
 175   char * retname = NULL;
 176   int retnamlen = 0, truncate=0;
 177  
 178   if (!inode->i_sb->u.isofs_sb.s_rock) return 0;
 179 
 180   SETUP_ROCK_RIDGE(de, chr, len);
 181  repeat:
 182   {
 183     struct rock_ridge * rr;
 184     int sig;
 185     
 186     while (len > 1){ /* There may be one byte for padding somewhere */
 187       rr = (struct rock_ridge *) chr;
 188       if (rr->len == 0) goto out; /* Something got screwed up here */
 189       sig = (chr[0] << 8) + chr[1];
 190       chr += rr->len; 
 191       len -= rr->len;
 192 
 193       switch(sig){
 194       case SIG('R','R'):
 195         if((rr->u.RR.flags[0] & RR_NM) == 0) goto out;
 196         break;
 197       case SIG('S','P'):
 198         CHECK_SP(goto out);
 199         break;
 200       case SIG('C','E'):
 201         CHECK_CE;
 202         break;
 203       case SIG('N','M'):
 204         if (truncate) break;
 205         if (rr->u.NM.flags & ~1) {
 206           printk("Unsupported NM flag settings (%d)\n",rr->u.NM.flags);
 207           break;
 208         };
 209         if (!retname){
 210           retname = (char *) kmalloc (255,GFP_KERNEL);
 211           /* This may be a waste, but we only
 212              need this for a moment.  The layers
 213              that call this function should
 214              deallocate the mem fairly soon
 215              after control is returned */
 216 
 217           *retname = 0; /* Zero length string */
 218           retnamlen = 0;
 219         };
 220         if((strlen(retname) + rr->len - 5) >= 254) {
 221           truncate = 1;
 222           break;
 223         };
 224         strncat(retname, rr->u.NM.name, rr->len - 5);
 225         retnamlen += rr->len - 5;
 226         break;
 227       case SIG('R','E'):
 228 #ifdef DEBUG
 229         printk("RR: RE (%x)\n", inode->i_ino);
 230 #endif
 231         if (buffer) kfree(buffer);
 232         if (retname) kfree(retname);
 233         return -1;
 234       default:
 235         break;
 236       }
 237     };
 238   }
 239   MAYBE_CONTINUE(repeat,inode);
 240   if(retname){
 241     *name = retname;
 242     *namlen = retnamlen;
 243     return 1;
 244   };
 245   return 0;  /* This file did not have a NM field */
 246  out:
 247   if(buffer) kfree(buffer);
 248   if (retname) kfree(retname);
 249   return 0;
 250 }
 251 
 252 int parse_rock_ridge_inode(struct iso_directory_record * de,
     /*  */
 253                            struct inode * inode){
 254   int len;
 255   unsigned char * chr;
 256   CONTINUE_DECLS;
 257 
 258   if (!inode->i_sb->u.isofs_sb.s_rock) return 0;
 259 
 260   SETUP_ROCK_RIDGE(de, chr, len);
 261  repeat:
 262   {
 263     int cnt, sig;
 264     struct inode * reloc;
 265     struct rock_ridge * rr;
 266     int rootflag;
 267     
 268     while (len > 1){ /* There may be one byte for padding somewhere */
 269       rr = (struct rock_ridge *) chr;
 270       if (rr->len == 0) goto out; /* Something got screwed up here */
 271       sig = (chr[0] << 8) + chr[1];
 272       chr += rr->len; 
 273       len -= rr->len;
 274       
 275       switch(sig){
 276       case SIG('R','R'):
 277         if((rr->u.RR.flags[0] & 
 278             (RR_PX | RR_TF | RR_SL | RR_CL)) == 0) goto out;
 279         break;
 280       case SIG('S','P'):
 281         CHECK_SP(goto out);
 282         break;
 283       case SIG('C','E'):
 284         CHECK_CE;
 285         break;
 286       case SIG('E','R'):
 287         printk("ISO9660 Extensions: ");
 288         { int p;
 289           for(p=0;p<rr->u.ER.len_id;p++) printk("%c",rr->u.ER.data[p]);
 290         };
 291           printk("\n");
 292         break;
 293       case SIG('P','X'):
 294         inode->i_mode  = isonum_733(rr->u.PX.mode);
 295         inode->i_nlink = isonum_733(rr->u.PX.n_links);
 296         inode->i_uid   = isonum_733(rr->u.PX.uid);
 297         inode->i_gid   = isonum_733(rr->u.PX.gid);
 298         break;
 299       case SIG('P','N'):
 300         { int high, low;
 301           high = isonum_733(rr->u.PN.dev_high);
 302           low = isonum_733(rr->u.PN.dev_low);
 303           inode->i_rdev = ((high << 8) | (low & 0xff)) & 0xffff;
 304         };
 305         break;
 306       case SIG('T','F'):
 307         /* Some RRIP writers incorrectly place ctime in the TF_CREATE field.
 308            Try and handle this correctly for either case. */
 309         cnt = 0; /* Rock ridge never appears on a High Sierra disk */
 310         if(rr->u.TF.flags & TF_CREATE) 
 311           inode->i_ctime = iso_date(rr->u.TF.times[cnt++].time, 0);
 312         if(rr->u.TF.flags & TF_MODIFY) 
 313           inode->i_mtime = iso_date(rr->u.TF.times[cnt++].time, 0);
 314         if(rr->u.TF.flags & TF_ACCESS) 
 315           inode->i_atime = iso_date(rr->u.TF.times[cnt++].time, 0);
 316         if(rr->u.TF.flags & TF_ATTRIBUTES) 
 317           inode->i_ctime = iso_date(rr->u.TF.times[cnt++].time, 0);
 318         break;
 319       case SIG('S','L'):
 320         {int slen;
 321          struct SL_component * slp;
 322          slen = rr->len - 5;
 323          slp = &rr->u.SL.link;
 324          inode->i_size = 0;
 325          while (slen > 1){
 326            rootflag = 0;
 327            switch(slp->flags &~1){
 328            case 0:
 329              inode->i_size += slp->len;
 330              break;
 331            case 2:
 332              inode->i_size += 1;
 333              break;
 334            case 4:
 335              inode->i_size += 2;
 336              break;
 337            case 8:
 338              rootflag = 1;
 339              inode->i_size += 1;
 340              break;
 341            default:
 342              printk("Symlink component flag not implemented\n");
 343            };
 344            slen -= slp->len + 2;
 345            slp = (struct SL_component *) (((char *) slp) + slp->len + 2);
 346 
 347            if(slen < 2) break;
 348            if(!rootflag) inode->i_size += 1;
 349          };
 350        };
 351         break;
 352       case SIG('R','E'):
 353         printk("Attempt to read inode for relocated directory\n");
 354         goto out;
 355       case SIG('C','L'):
 356 #ifdef DEBUG
 357         printk("RR CL (%x)\n",inode->i_ino);
 358 #endif
 359         inode->u.isofs_i.i_first_extent = isonum_733(rr->u.CL.location) <<
 360                 (ISOFS_BLOCK_BITS - ISOFS_BUFFER_BITS(inode));
 361         reloc = iget(inode->i_sb, inode->u.isofs_i.i_first_extent << ISOFS_BUFFER_BITS(inode));
 362         inode->i_mode = reloc->i_mode;
 363         inode->i_nlink = reloc->i_nlink;
 364         inode->i_uid = reloc->i_uid;
 365         inode->i_gid = reloc->i_gid;
 366         inode->i_rdev = reloc->i_rdev;
 367         inode->i_size = reloc->i_size;
 368         inode->i_atime = reloc->i_atime;
 369         inode->i_ctime = reloc->i_ctime;
 370         inode->i_mtime = reloc->i_mtime;
 371         iput(reloc);
 372         break;
 373       default:
 374         break;
 375       }
 376     };
 377   }
 378   MAYBE_CONTINUE(repeat,inode);
 379   return 0;
 380  out:
 381   if(buffer) kfree(buffer);
 382   return 0;
 383 }
 384 
 385 
 386 /* Returns the name of the file that this inode is symlinked to.  This is
 387    in malloc'd memory, so it needs to be freed, once we are through with it */
 388 
 389 char * get_rock_ridge_symlink(struct inode * inode)
     /*  */
 390 {
 391   unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
 392   unsigned char bufbits = ISOFS_BUFFER_BITS(inode);
 393   struct buffer_head * bh;
 394   unsigned char * pnt;
 395   void * cpnt = NULL;
 396   char * rpnt;
 397   struct iso_directory_record * raw_inode;
 398   CONTINUE_DECLS;
 399   int block;
 400   int sig;
 401   int rootflag;
 402   int len;
 403   unsigned char * chr;
 404   struct rock_ridge * rr;
 405   
 406   if (!inode->i_sb->u.isofs_sb.s_rock)
 407     panic("Cannot have symlink with high sierra variant of iso filesystem\n");
 408 
 409   rpnt = 0;
 410   
 411   block = inode->i_ino >> bufbits;
 412   if (!(bh=bread(inode->i_dev,block, bufsize))) {
 413     printk("unable to read i-node block");
 414     return NULL;
 415   };
 416   
 417   pnt = ((unsigned char *) bh->b_data) + (inode->i_ino & (bufsize - 1));
 418   
 419   raw_inode = ((struct iso_directory_record *) pnt);
 420   
 421   if ((inode->i_ino & (bufsize - 1)) + *pnt > bufsize){
 422     int frag1, offset;
 423     
 424     offset = (inode->i_ino & (bufsize - 1));
 425     frag1 = bufsize - offset;
 426     cpnt = kmalloc(*pnt,GFP_KERNEL);
 427     if(!cpnt) return NULL;
 428     memcpy(cpnt, bh->b_data + offset, frag1);
 429     brelse(bh);
 430     if (!(bh = bread(inode->i_dev,++block, bufsize))) {
 431       kfree(cpnt);
 432       printk("unable to read i-node block");
 433       return NULL;
 434     };
 435     offset += *pnt - bufsize;
 436     memcpy((char *)cpnt+frag1, bh->b_data, offset);
 437     pnt = ((unsigned char *) cpnt);
 438     raw_inode = ((struct iso_directory_record *) pnt);
 439   };
 440   
 441   /* Now test for possible Rock Ridge extensions which will override some of
 442      these numbers in the inode structure. */
 443   
 444   SETUP_ROCK_RIDGE(raw_inode, chr, len);
 445   
 446  repeat:
 447   while (len > 1){ /* There may be one byte for padding somewhere */
 448     if (rpnt) break;
 449     rr = (struct rock_ridge *) chr;
 450     if (rr->len == 0) goto out; /* Something got screwed up here */
 451     sig = (chr[0] << 8) + chr[1];
 452     chr += rr->len; 
 453     len -= rr->len;
 454     
 455     switch(sig){
 456     case SIG('R','R'):
 457       if((rr->u.RR.flags[0] & RR_SL) == 0) goto out;
 458       break;
 459     case SIG('S','P'):
 460       CHECK_SP(goto out);
 461       break;
 462     case SIG('S','L'):
 463       {int slen;
 464        struct SL_component * slp;
 465        slen = rr->len - 5;
 466        slp = &rr->u.SL.link;
 467        while (slen > 1){
 468          if (!rpnt){
 469            rpnt = (char *) kmalloc (inode->i_size +1, GFP_KERNEL);
 470            *rpnt = 0;
 471          };
 472          rootflag = 0;
 473          switch(slp->flags &~1){
 474          case 0:
 475            strncat(rpnt,slp->text, slp->len);
 476            break;
 477          case 2:
 478            strcat(rpnt,".");
 479            break;
 480          case 4:
 481            strcat(rpnt,"..");
 482            break;
 483          case 8:
 484            rootflag = 1;
 485            strcat(rpnt,"/");
 486            break;
 487          default:
 488            printk("Symlink component flag not implemented (%d)\n",slen);
 489          };
 490          slen -= slp->len + 2;
 491          slp = (struct SL_component *) (((char *) slp) + slp->len + 2);
 492 
 493          if(slen < 2) break;
 494          if(!rootflag) strcat(rpnt,"/");
 495        };
 496        break;
 497      default:
 498        break;
 499      }
 500     };
 501   };
 502   MAYBE_CONTINUE(repeat,inode);
 503   brelse(bh);
 504   
 505   if (cpnt) {
 506     kfree(cpnt);
 507     cpnt = NULL;
 508   };
 509 
 510   return rpnt;
 511  out:
 512   if(buffer) kfree(buffer);
 513   return 0;
 514 }
 515 
 516 
 517 
 518 
 519 
 520
/* */
root/fs/isofs/rock.c

DEFINITIONS
