/*
 *  ISO 9660 filesystem backend for GRUB (GRand Unified Bootloader)
 *  including Rock Ridge Extensions support
 *
 *  Copyright (C) 1998, 1999  Kousuke Takai  <tak@kmc.kyoto-u.ac.jp>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
/*
 *  References:
 *      linux/fs/isofs/rock.[ch]
 *      mkisofs-1.11.1/diag/isoinfo.c
 *      mkisofs-1.11.1/iso9660.h
 *              (all are written by Eric Youngdale)
 *
 *  Modifications by:
 *      Leonid Lisovskiy   <lly@pisem.net>      2003
 */

#ifdef FSYS_ISO9660

#include "shared.h"
#include "filesys.h"
#include "iso9660.h"

/* iso9660 super-block data in memory */
struct iso_sb_info {
  unsigned long vol_sector;

};

/* iso fs inode data in memory */
struct iso_inode_info {
  unsigned long file_start;
};

#define ISO_SUPER       \
    ((struct iso_sb_info *)(FSYS_BUF))
#define INODE           \
    ((struct iso_inode_info *)(FSYS_BUF+sizeof(struct iso_sb_info)))
#define PRIMDESC        ((struct iso_primary_descriptor *)(FSYS_BUF + 2048))
#define DIRREC          ((struct iso_directory_record *)(FSYS_BUF + 4096))
#define RRCONT_BUF      ((unsigned char *)(FSYS_BUF + 6144))
#define NAME_BUF        ((unsigned char *)(FSYS_BUF + 8192))


static inline unsigned long
grub_log2 (unsigned long word)
{
  asm volatile ("bsfl %1,%0"
                :          "=r" (word)
                :          "r" (word));
  return word;
}
#define log2 grub_log2

static int
iso9660_devread (int sector, int byte_offset, int byte_len, char *buf)
{
  static int read_count = 0, threshold = 2;
  unsigned short sector_size_lg2 = log2(buf_geom.sector_size);

  /*
   * We have to use own devread() function since BIOS return wrong geometry
   */
  if (sector < 0)
    {
      errnum = ERR_OUTSIDE_PART;
      return 0;
    }
  if (byte_len <= 0)
    return 1;

  sector += (byte_offset >> sector_size_lg2);
  byte_offset &= (buf_geom.sector_size - 1);
  asm volatile ("shl%L0 %1,%0"
                : "=r"(sector)
                : "Ic"((int8_t)(ISO_SECTOR_BITS - sector_size_lg2)),
                "0"(sector));

#if !defined(STAGE1_5)
  if (disk_read_hook && debug)
    printf ("<%d, %d, %d>", sector, byte_offset, byte_len);
#endif /* !STAGE1_5 */

  read_count += (byte_len >> 9);
  if ((read_count >> 11) > threshold) {
        noisy_printf(".");
        threshold += 2; /* one dot every 2 MB */
  }
  return rawread(current_drive, part_start + sector, byte_offset, byte_len, buf);
}

int
iso9660_mount (void)
{
  unsigned int sector;

  /*
   *  Because there is no defined slice type ID for ISO-9660 filesystem,
   *  this test will pass only either (1) if entire disk is used, or
   *  (2) if current partition is BSD style sub-partition whose ID is
   *  ISO-9660.
   */
  if ((current_partition != 0xFFFFFF)
      && !IS_PC_SLICE_TYPE_BSD_WITH_FS(current_slice, FS_ISO9660))
    return 0;

  /*
   *  Currently, only FIRST session of MultiSession disks are supported !!!
   */
  for (sector = 16 ; sector < 32 ; sector++)
    {
      if (!iso9660_devread(sector, 0, sizeof(*PRIMDESC), (char *)PRIMDESC)) 
        break;
      /* check ISO_VD_PRIMARY and ISO_STANDARD_ID */
      if (PRIMDESC->type.l == ISO_VD_PRIMARY
          && !memcmp(PRIMDESC->id, ISO_STANDARD_ID, sizeof(PRIMDESC->id)))
        {
          ISO_SUPER->vol_sector = sector;
          INODE->file_start = 0;
          fsmax = PRIMDESC->volume_space_size.l;
          return 1;
        }
    }

  return 0;
}

int
iso9660_dir (char *dirname)
{
  struct iso_directory_record *idr;
  RR_ptr_t rr_ptr;
  struct rock_ridge *ce_ptr;
  unsigned int pathlen;
  int size;
  unsigned int extent;
  unsigned char file_type;
  unsigned int rr_len;
  unsigned char rr_flag;

  idr = &PRIMDESC->root_directory_record;
  INODE->file_start = 0;

  do
    {
      while (*dirname == '/')   /* skip leading slashes */
        dirname++;
      /* pathlen = strcspn(dirname, "/\n\t "); */
      for (pathlen = 0 ;
           dirname[pathlen]
             && !isspace(dirname[pathlen]) && dirname[pathlen] != '/' ;
           pathlen++)
        ;

      size = idr->size.l;
      extent = idr->extent.l;

      while (size > 0)
        {
          if (!iso9660_devread(extent, 0, ISO_SECTOR_SIZE, (char *)DIRREC))
            {
              errnum = ERR_FSYS_CORRUPT;
              return 0;
            }
          extent++;

          idr = (struct iso_directory_record *)DIRREC;
          for (; idr->length.l > 0;
               idr = (struct iso_directory_record *)((char *)idr + idr->length.l) )
            {
              const char *name = idr->name;
              unsigned int name_len = idr->name_len.l;

              file_type = (idr->flags.l & 2) ? ISO_DIRECTORY : ISO_REGULAR;
              if (name_len == 1)
                {
                  if ((name[0] == 0) || /* self */
                      (name[0] == 1))   /* parent */
                    continue;
                }
              if (name_len > 2 && CHECK2(name + name_len - 2, ';', '1'))
                {
                  name_len -= 2;        /* truncate trailing file version */
                  if (name_len > 1 && name[name_len - 1] == '.')
                    name_len--;         /* truncate trailing dot */
                }

              /*
               *  Parse Rock-Ridge extension
               */
              rr_len = (idr->length.l - idr->name_len.l
                        - sizeof(struct iso_directory_record)
                        + sizeof(idr->name));
              rr_ptr.ptr = ((unsigned char *)idr + idr->name_len.l
                            + sizeof(struct iso_directory_record)
                            - sizeof(idr->name));
              if (rr_ptr.i & 1)
                rr_ptr.i++, rr_len--;
              ce_ptr = NULL;
              rr_flag = RR_FLAG_NM | RR_FLAG_PX /*| RR_FLAG_SL*/;

              while (rr_len >= 4)
                {
                  if (rr_ptr.rr->version != 1)
                    {
#ifndef STAGE1_5
                      if (debug)
                        printf(
                               "Non-supported version (%d) RockRidge chunk "
                               "`%c%c'\n", rr_ptr.rr->version,
                               rr_ptr.rr->signature & 0xFF,
                               rr_ptr.rr->signature >> 8);
#endif
                    }
                  else
                    {
                      switch (rr_ptr.rr->signature)
                        {
                        case RRMAGIC('R', 'R'):
                          if ( rr_ptr.rr->len >= (4+sizeof(struct RR)))
                            rr_flag &= rr_ptr.rr->u.rr.flags.l;
                          break;
                        case RRMAGIC('N', 'M'):
                          name = rr_ptr.rr->u.nm.name;
                          name_len = rr_ptr.rr->len - (4+sizeof(struct NM));
                          rr_flag &= ~RR_FLAG_NM;
                          break;
                        case RRMAGIC('P', 'X'):
                          if (rr_ptr.rr->len >= (4+sizeof(struct PX)))
                            {
                              file_type = ((rr_ptr.rr->u.px.mode.l & POSIX_S_IFMT)
                                           == POSIX_S_IFREG
                                           ? ISO_REGULAR
                                           : ((rr_ptr.rr->u.px.mode.l & POSIX_S_IFMT)
                                              == POSIX_S_IFDIR
                                              ? ISO_DIRECTORY : ISO_OTHER));
                              rr_flag &= ~RR_FLAG_PX;
                            }
                          break;
                        case RRMAGIC('C', 'E'):
                          if (rr_ptr.rr->len >= (4+sizeof(struct CE)))
                            ce_ptr = rr_ptr.rr;
                          break;
#if 0           // RockRidge symlinks are not supported yet
                        case RRMAGIC('S', 'L'):
                          {
                            int slen;
                            unsigned char rootflag, prevflag;
                            char *rpnt = NAME_BUF+1024;
                            struct SL_component *slp;

                            slen = rr_ptr.rr->len - (4+1);
                            slp = &rr_ptr.rr->u.sl.link;
                            while (slen > 1)
                              {
                                rootflag = 0;
                                switch (slp->flags.l)
                                  {
                                  case 0:
                                    memcpy(rpnt, slp->text, slp->len);
                                    rpnt += slp->len;
                                    break;
                                  case 4:
                                    *rpnt++ = '.';
                                    /* fallthru */
                                  case 2:
                                    *rpnt++ = '.';
                                    break;
                                  case 8:
                                    rootflag = 1;
                                    *rpnt++ = '/';
                                    break;
                                  default:
                                    printf("Symlink component flag not implemented (%d)\n",
                                           slp->flags.l);
                                    slen = 0;
                                    break;
                                  }
                                slen -= slp->len + 2;
                                prevflag = slp->flags.l;
                                slp = (struct SL_component *) ((char *) slp + slp->len + 2);

                                if (slen < 2)
                                  {
                                    /*
                                     * If there is another SL record, and this component
                                     * record isn't continued, then add a slash.
                                     */
                                    if ((!rootflag) && (rr_ptr.rr->u.sl.flags.l & 1) && !(prevflag & 1))
                                      *rpnt++='/';
                                    break;
                                  }

                                /*
                                 * If this component record isn't continued, then append a '/'.
                                 */
                                if (!rootflag && !(prevflag & 1))
                                  *rpnt++ = '/';
                              }
                            *rpnt++ = '\0';
                            grub_putstr(NAME_BUF+1024);// debug print!
                          }
                          rr_flag &= ~RR_FLAG_SL;
                          break;
#endif
                        default:
                          break;
                        }
                    }
                  if (!rr_flag)
                    /*
                     * There is no more extension we expects...
                     */
                    break;

                  rr_len -= rr_ptr.rr->len;
                  rr_ptr.ptr += rr_ptr.rr->len;
                  if (rr_len < 4 && ce_ptr != NULL)
                    {
                      /* preserve name before loading new extent. */
                      if( RRCONT_BUF <= (unsigned char *)name
                          && (unsigned char *)name < RRCONT_BUF + ISO_SECTOR_SIZE )
                        {
                          memcpy(NAME_BUF, name, name_len);
                          name = NAME_BUF;
                        }
                      rr_ptr.ptr = RRCONT_BUF + ce_ptr->u.ce.offset.l;
                      rr_len = ce_ptr->u.ce.size.l;
                      if (!iso9660_devread(ce_ptr->u.ce.extent.l, 0, ISO_SECTOR_SIZE, RRCONT_BUF))
                        {
                          errnum = 0;   /* this is not fatal. */
                          break;
                        }
                      ce_ptr = NULL;
                    }
                } /* rr_len >= 4 */

              filemax = MAXINT;
              if (name_len >= pathlen
                  && !memcmp(name, dirname, pathlen))
                {
                  if (dirname[pathlen] == '/' || !print_possibilities)
                    {
                      /*
                       *  DIRNAME is directory component of pathname,
                       *  or we are to open a file.
                       */
                      if (pathlen == name_len)
                        {
                          if (dirname[pathlen] == '/')
                            {
                              if (file_type != ISO_DIRECTORY)
                                {
                                  errnum = ERR_BAD_FILETYPE;
                                  return 0;
                                }
                              goto next_dir_level;
                            }
                          if (file_type != ISO_REGULAR)
                            {
                              errnum = ERR_BAD_FILETYPE;
                              return 0;
                            }
                          INODE->file_start = idr->extent.l;
                          filepos = 0;
                          filemax = idr->size.l;
                          return 1;
                        }
                    }
                  else  /* Completion */
                    {
#ifndef STAGE1_5
                      if (print_possibilities > 0)
                        print_possibilities = -print_possibilities;
                      memcpy(NAME_BUF, name, name_len);
                      NAME_BUF[name_len] = '\0';
                      print_a_completion (NAME_BUF);
#endif
                    }
                }
            } /* for */

          size -= ISO_SECTOR_SIZE;
        } /* size>0 */

      if (dirname[pathlen] == '/' || print_possibilities >= 0)
        {
          errnum = ERR_FILE_NOT_FOUND;
          return 0;
        }

    next_dir_level:
      dirname += pathlen;

    } while (*dirname == '/');

  return 1;
}

int
iso9660_read (char *buf, int len)
{
  int sector, blkoffset, size, ret;

  if (INODE->file_start == 0)
    return 0;

  ret = 0;
  blkoffset = filepos & (ISO_SECTOR_SIZE - 1);
  sector = filepos >> ISO_SECTOR_BITS;
  while (len > 0)
    {
      size = ISO_SECTOR_SIZE - blkoffset;
      if (size > len)
        size = len;

      disk_read_func = disk_read_hook;

      if (!iso9660_devread(INODE->file_start + sector, blkoffset, size, buf))
        return 0;

      disk_read_func = NULL;

      len -= size;
      buf += size;
      ret += size;
      filepos += size;
      sector++;
      blkoffset = 0;
    }

  return ret;
}

#endif /* FSYS_ISO9660 */