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/*

 * Project: HARTIK (HA-rd R-eal TI-me K-ernel)

 *

 * Coordinators: Giorgio Buttazzo <giorgio@sssup.it>

 *               Gerardo Lamastra <gerardo@sssup.it>

 *

 * Authors     : Massimiliano Giorgi <massy@hartik.sssup.it>

 * (see authors.txt for full list of hartik's authors)

 *

 * ReTiS Lab (Scuola Superiore S.Anna - Pisa - Italy)

 *

 * http://www.sssup.it

 * http://retis.sssup.it

 * http://hartik.sssup.it

 */

/*

 * Copyright (C) 1999 Massimiliano Giorgi

 *

 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 *

 */

/*

 * CVS :        $Id: msdos_s.c,v 1.1.1.1 2002-03-29 14:12:50 pj Exp $

 *

 * File:        $File$

 * Revision:    $Revision: 1.1.1.1 $

 * Last update: $Date: 2002-03-29 14:12:50 $

 */

#include <fs/types.h>

#include <fs/const.h>

#include <fs/stat.h>

#include <fs/fsinit.h>

#include <fs/fsind.h>

#include <fs/util.h>

#include <fs/mount.h>

#include <fs/util.h>

#include <fs/mount.h>

#include <fs/assert.h>

#include "dcache.h"

#include "fs.h"

#include "msdos/msdos.h"

#include "msdos/msdos_s.h"

#include "msdos/msdos_i.h"

#define DEBUG_READSUPER KERN_DEBUG

#undef DEBUG_READSUPER

#ifdef DEBUG_READSUPER

#define printk0(fmt,args...) \

        printk(DEBUG_READSUPER fmt,##args)

#else

#define printk0(fmt,args...)

#endif

static struct super_block *msdos_read_super(__dev_t dev, __uint8_t fs_ind,

                                            struct mount_opts *options);

static struct file_system_type msdosfs[]={

  {"fat16",0,FS_MSDOS,msdos_read_super},

};

/*{"fat16+",0,FS_DOSBIG,msdos_read_super}*/

int msdos_fs_init(FILESYSTEM_PARMS *ptr)

{

  int i;

  for (i=0;i<sizeof(msdosfs)/sizeof(struct file_system_type);i++)

    filesystem_register(msdosfs+i);

  return 0;

}

/*-----------------------------------------*/

/*

 * boot record (akin to super block)

 */

struct bootrecord {

  __uint8_t  reserved[3];

  char       oemname[8];

  __uint16_t bytespersector;

  __uint8_t  sectorspercluster;

  __uint16_t hiddensectors;

  __uint8_t  fatsnumber;

  __uint16_t rootentry;

  __uint16_t sectors;

  __uint8_t  media;

  __uint16_t sectorsperfat;

  __uint16_t sectorpertrak;

  __uint16_t headsperdisk;

  __uint32_t hiddensectors32;

  __uint32_t sectors32;

  __uint16_t physicaldrive;

  __uint8_t  signature;

  __uint8_t  serialnumber[4];

  char       volumelabel[11];

  char       fattype[8];

} __attribute__ ((packed));

static char *chr2str(char *s, int n)

{

  static char str[12];

  memcpy(str,s,n);

  str[n]='\0';

  return str;

}

static __inline__ __uint32_t br_numhiddensectors(struct bootrecord *br)

{

  return br->hiddensectors?(long)br->hiddensectors:(long)br->hiddensectors32;

}

static __inline__ __uint32_t br_numsectors(struct bootrecord *br)

{

  return br->sectors?(long)br->sectors:(long)br->sectors32;

}

static void dump_br(struct bootrecord *br) __attribute__ ((unused));

static void dump_br(struct bootrecord *br)

{

  printk(KERN_DEBUG "oem     : %s",chr2str(br->oemname,8));

  printk(KERN_DEBUG "label   : %s",chr2str(br->volumelabel,11));

  printk(KERN_DEBUG "fat type: %s",chr2str(br->fattype,8));

  printk(KERN_DEBUG "serial  : %02x%02x-%02x%02x",br->serialnumber[3],

         br->serialnumber[2],

         br->serialnumber[1],

         br->serialnumber[0]);

  printk(KERN_DEBUG "sector  : %i bytes",(int)br->bytespersector);

  printk(KERN_DEBUG "cluster : %i sectors",(int)br->sectorspercluster);

  printk(KERN_DEBUG "fat     : %i copies",(int)br->fatsnumber);

  printk(KERN_DEBUG "root    : %i sectors",

         br->rootentry*32/br->bytespersector);

  printk(KERN_DEBUG "fat     : %i sectors",(int)br->sectorsperfat);

  printk(KERN_DEBUG "hidden  : %li sectors",br->hiddensectors?

         (long)br->hiddensectors:(long)br->hiddensectors32);

  printk(KERN_DEBUG "size    : %li sectors",br->sectors?

         (long)br->sectors:(long)br->sectors32);

}

/* from Linux */

/* time,date conversions routine */

static int day_n[]={

  0,31,59,90,120,151,181,212,243,273,304,334,0,0,0,0

};

/* Convert a MS-DOS time/date pair to a UNIX date (seconds since 1 1 70). */

__time_t date_dos2unix(__uint16_t time,__uint16_t date)

{

  int month,year;

  __time_t secs;

  month = ((date >> 5) & 15)-1;

  year = date >> 9;

  secs = (time & 31)*2l+60l*((time >> 5) & 63)+(time >> 11)*3600l+86400l*

    ((date & 31)-1+day_n[month]+(year/4l)+year*365l-((year & 3) == 0 &&

                                                   month < 2 ? 1 : 0)+3653l);

  /* days since 1.1.70 plus 80's leap day */

  /*secs += sys_tz.tz_minuteswest*60;*/

  /*if (sys_tz.tz_dsttime) secs -= 3600;*/

  return secs;

}

/* Convert linear UNIX date to a MS-DOS time/date pair. */

void date_unix2dos(__time_t unix_date,__uint16_t *time,

    __uint16_t *date)

{

  int day,year,nl_day,month;

  /*unix_date -= sys_tz.tz_minuteswest*60;*/

  /*if (sys_tz.tz_dsttime) unix_date += 3600;*/

  *time = (unix_date % 60)/2+(((unix_date/60) % 60) << 5)+

    (((unix_date/3600) % 24) << 11);

  day = unix_date/86400-3652;

  year = day/365;

  if ((year+3)/4+365*year > day) year--;

  day -= (year+3)/4+365*year;

  if (day == 59 && !(year & 3)) {

    nl_day = day;

    month = 2;

  }

  else {

    nl_day = (year & 3) || day <= 59 ? day : day-1;

    for (month = 0; month < 12; month++)

      if (day_n[month] > nl_day) break;

  }

  *date = nl_day-day_n[month-1]+1+(month << 5)+(year << 9);

}

/*

 *

 * Super operations

 *

 */

static int  msdos_init_inode(struct inode *in);

static int  msdos_read_inode(struct inode *in);

static int  msdos_write_inode(struct inode *in);

static int  msdos_put_super(struct super_block *sb);

static int  msdos_delete_inode(struct inode *in);

static struct super_operations msdos_super_operations={

  msdos_init_inode,

  msdos_read_inode,

  msdos_write_inode,

  msdos_put_super,

  msdos_delete_inode

};

static int msdos_put_super(struct super_block *sb)

{

  return 0;

}

static int msdos_init_inode(struct inode *in)

{

  __uint16_t  cluster;

  __uint32_t lsector;

  __uint16_t  deoffs,offs;

  /*i_sb gia' messo*/

  /*i_st.st_ino gia' messo*/

  cluster=INODE2CLUSTER(in->i_st.st_ino);

  deoffs=INODE2DEOFFS(in->i_st.st_ino);

  _assert(cluster!=ROOT_CLUSTER);

  if (cluster==SPECIAL_CLUSTER)

    lsector=MSDOS_SB(in->i_sb).lroot;

  else

    lsector=(cluster-2)*MSDOS_SB(in->i_sb).spc+MSDOS_SB(in->i_sb).ldata;    

  lsector+=(__uint16_t)(((__uint32_t)deoffs*DIRENTRYSIZE)/SECTORSIZE);

  offs=(((__uint16_t)deoffs*DIRENTRYSIZE)%SECTORSIZE)/DIRENTRYSIZE;

  MSDOS_I(in).lsector=lsector;

  MSDOS_I(in).offs=offs;

  in->i_st.st_dev=in->i_sb->sb_dev;

  in->i_st.st_mode=__DEFFILEMODE;

  in->i_st.st_mode|=__S_IFREG;

  in->i_st.st_blksize=SECTORSIZE;

  in->i_st.st_nlink=1;

  in->i_st.st_uid=0;

  in->i_st.st_gid=0;

  in->i_st.st_size=0;  

  in->i_st.st_atime=in->i_st.st_mtime=in->i_st.st_ctime=0;

  /* for safety */

  if (in->i_sb->sb_mopts.flags&MOUNT_FLAG_RW)

    in->i_op=&msdos_inode_rw_operations;

  else

    in->i_op=&msdos_inode_ro_operations;

  MSDOS_I(in).scluster=FREE_CLUSTER;

  in->i_dirty=1;

  return 0;

}

static int msdos_read_inode(struct inode *in)

{

  struct directoryentry *den;

  dcache_t *ptr;

  __uint16_t  cluster;

  __uint32_t lsector;

  __uint16_t  deoffs,offs;

  /*i_sb gia' messo*/

  /*i_st.st_ino gia' messo*/

  cluster=INODE2CLUSTER(in->i_st.st_ino);

  deoffs=INODE2DEOFFS(in->i_st.st_ino);

  if (cluster==ROOT_CLUSTER) {

    /* special case: root inode */

    MSDOS_I(in).lsector=0;

    MSDOS_I(in).offs=0;

    MSDOS_I(in).scluster=ROOT_CLUSTER;

    in->i_st.st_dev=in->i_sb->sb_dev;

    in->i_st.st_mode=__S_IRWXO|__S_IRWXG|__S_IRWXU;

    in->i_st.st_mode|=__S_IFDIR;

    in->i_st.st_nlink=1+1; /* must be fixed */

    in->i_st.st_blksize=SECTORSIZE;

    in->i_st.st_uid=0;

    in->i_st.st_gid=0;

    in->i_st.st_size=MSDOS_SB(in->i_sb).rootsect*SECTORSIZE;  

    in->i_st.st_atime=in->i_st.st_mtime=in->i_st.st_ctime=0;

    /* for safety */

    if (in->i_sb->sb_mopts.flags&MOUNT_FLAG_RW)

      in->i_op=&msdos_inode_rw_operations;

    else

      in->i_op=&msdos_inode_ro_operations;

    in->i_dirty=0;

    return 0;

  } else if (cluster==SPECIAL_CLUSTER) {

    /* special case: an inode on root directory */

    lsector=MSDOS_SB(in->i_sb).lroot;

  } else {

    /* normal inode */

    lsector=(cluster-2)*MSDOS_SB(in->i_sb).spc+MSDOS_SB(in->i_sb).ldata;

  }

  lsector+=(__uint16_t)(((__uint32_t)deoffs*DIRENTRYSIZE)/SECTORSIZE);

  offs=(((__uint16_t)deoffs*DIRENTRYSIZE)%SECTORSIZE)/DIRENTRYSIZE;

  MSDOS_I(in).lsector=lsector;

  MSDOS_I(in).offs=offs;

  ptr=dcache_lock(in->i_sb->sb_dev,lsector);

  if (ptr==NULL) return -1;

  den=(struct directoryentry *)(ptr->buffer)+offs;

  in->i_st.st_dev=in->i_sb->sb_dev;

  in->i_st.st_mode=__S_IRWXO|__S_IRWXG|__S_IRWXU;

  in->i_st.st_mode|=(den->attribute&ATTR_DIR?__S_IFDIR:__S_IFREG);

  in->i_st.st_nlink=1+(__S_ISDIR(in->i_st.st_mode)?1:0); /* must be fixed */

  in->i_st.st_blksize=SECTORSIZE;

  in->i_st.st_uid=0;

  in->i_st.st_gid=0;

  in->i_st.st_size=den->size;  

  in->i_st.st_atime=in->i_st.st_mtime=in->i_st.st_ctime=

    date_dos2unix(den->time,den->date);  

  /* for safety */

  if (in->i_sb->sb_mopts.flags&MOUNT_FLAG_RW)

    in->i_op=&msdos_inode_rw_operations;

  else

    in->i_op=&msdos_inode_ro_operations;

  if (den->cluster==FREECLUSTER)

    MSDOS_I(in).scluster=FREE_CLUSTER;

  else

    MSDOS_I(in).scluster=den->cluster;

  in->i_dirty=0;

  dcache_unlock(ptr);

  return 0;

}

static int msdos_write_inode(struct inode *in)

{

  struct directoryentry *den;

  dcache_t              *ptr;

  __uint16_t            cluster;

  cluster=INODE2CLUSTER(in->i_st.st_ino);

  if (cluster==ROOT_CLUSTER) return 0;

  ptr=dcache_acquire(in->i_sb->sb_dev,MSDOS_I(in).lsector);

  if (ptr==NULL) {

    dcache_release(ptr);

    return -1;

  }

  den=(struct directoryentry *)(ptr->buffer)+MSDOS_I(in).offs;

  //printk("writing inode\n start cluster=0x%04x\n",MSDOS_I(in).scluster);

  cluster=MSDOS_I(in).scluster;

  _assert(cluster!=NO_CLUSTER&&

          cluster!=ROOT_CLUSTER&&

          cluster!=SPECIAL_CLUSTER);

  if (cluster==FREE_CLUSTER) cluster=FREECLUSTER;

  date_unix2dos(in->i_st.st_atime,&den->time,&den->date);

  den->cluster=cluster;

  den->size=in->i_st.st_size;

  in->i_dirty=0;

  dcache_dirty(ptr);

  dcache_release(ptr);         

  return 0;

}

static int msdos_delete_inode(struct inode *in)

{

  struct directoryentry *den;

  dcache_t              *ptr;

  __uint16_t            cluster;

  cluster=INODE2CLUSTER(in->i_st.st_ino);

  if (cluster==ROOT_CLUSTER) return 0;

  ptr=dcache_acquire(in->i_sb->sb_dev,MSDOS_I(in).lsector);

  if (ptr==NULL) {

    dcache_release(ptr);

    return -1;

  }

  den=(struct directoryentry *)(ptr->buffer)+MSDOS_I(in).offs;

  msdos_markentryfree(den);

  dcache_dirty(ptr);  

  dcache_release(ptr);         

  return 0;

}

static int msdos_dump_inode(struct inode *in) __attribute__((unused));

static int msdos_dump_inode(struct inode *in)

{

  printk(KERN_DEBUG "dev   : %i",in->i_st.st_dev);

  printk(KERN_DEBUG "inode : %08lx",(long)in->i_st.st_ino);

  printk(KERN_DEBUG "mode  : %04x",in->i_st.st_mode);

  printk(KERN_DEBUG "nlink : %i",in->i_st.st_nlink);

  printk(KERN_DEBUG "uid   : %i",in->i_st.st_uid);

  printk(KERN_DEBUG "gid   : %i",in->i_st.st_gid);

  //printk(KERN_DEBUG "rdev  : %i",in->i_st.st_rdev);

  printk(KERN_DEBUG "size  : %li",in->i_st.st_size);

  printk(KERN_DEBUG "atime : %li",(long)in->i_st.st_atime);

  printk(KERN_DEBUG "mtime : %li",(long)in->i_st.st_mtime);

  printk(KERN_DEBUG "ctime : %li",(long)in->i_st.st_ctime);

  printk(KERN_DEBUG "lsect : %li",(long)MSDOS_I(in).lsector);

  printk(KERN_DEBUG "off   : %li",(long)MSDOS_I(in).offs);

  printk(KERN_DEBUG "sclust: %li",(long)MSDOS_I(in).scluster);

  return 0;

}

/*

 *

 * Mount operation

 *

 */

#define MSDOSSBSIGNATURE 0x29

static struct super_block *msdos_read_super(__dev_t dev, __uint8_t fs_ind,

                                            struct mount_opts *opts)

{

  struct inode       *in;

  struct bootrecord  *br;

  struct super_block *sb;

  dcache_t           *dc;

  int                res;

  printk0("msdos_read_super(): START");

  dc=dcache_lock(dev,0);

  if (dc==NULL) {

    printk(KERN_DEBUG "msdos_read_super FAIL: can't read/lock cache");

    return NULL;

  }

  br=(struct bootrecord*)dc->buffer;

  if (br->fatsnumber>MAXFATS) {

    dcache_unlock(dc);

    printk(KERN_DEBUG "msdos_read_super FAIL: too many FATS (%i)",

           br->fatsnumber);

    return NULL;

  }  

  if (br->signature!=MSDOSSBSIGNATURE) {

    dcache_unlock(dc);

    printk(KERN_DEBUG "msdos_read_super FAIL: can't find MSDOS signature");

    return NULL;

  }

  printk0("msdos_read_super(): boot sector locked");

  sb=super_getblock();

  if (sb==NULL) {

    dcache_unlock(dc);

    printk(KERN_DEBUG "msdos_read_super FAIL: can't have a super struct");

    return NULL;

  }

  printk0("msdos_read_super(): super structure allocated");

  if (opts==NULL) {msdosfs_std_parms(sb->sb_mopts);}

  else memcpy(&sb->sb_mopts,opts,sizeof(struct mount_opts));

  sb->sb_dev=dev;

  sb->sb_op=&msdos_super_operations;

  sb->sb_dop=&msdos_dentry_operations;

  MSDOS_SB(sb).lfat=br_numhiddensectors(br);

  MSDOS_SB(sb).lroot=MSDOS_SB(sb).lfat+

    (__uint32_t)br->sectorsperfat*br->fatsnumber;

  MSDOS_SB(sb).ldata=MSDOS_SB(sb).lroot+

    br->rootentry*DIRENTRYSIZE/br->bytespersector;

  MSDOS_SB(sb).lsize=br_numsectors(br)+br_numhiddensectors(br);

  MSDOS_SB(sb).spc=br->sectorspercluster;

  MSDOS_SB(sb).rootsect=(__uint32_t)br->rootentry*DIRENTRYSIZE/

    br->bytespersector;

  MSDOS_SB(sb).spf=br->sectorsperfat;

  MSDOS_SB(sb).nfat=br->fatsnumber;

  MSDOS_SB(sb).stclust=STARTCLUSTER;

  printk0("msdos_read_super(): super structure filled");

  in=catch_inode();

  if (in==NULL) {

    super_freeblock(sb);

    dcache_unlock(dc);

    printk(KERN_DEBUG "msdos_read_super FAIL: can't have an inode struct");

    return NULL;    

  }

  printk0("msdos_read_super(): inode structure allocated");

  sb->sb_root=in;

  in->i_sb=sb;

  in->i_st.st_ino=ROOT_INODE;

  res=msdos_read_inode(in);

  if (res!=0) {

    free_inode(in);

    super_freeblock(sb);

    dcache_unlock(dc);

    printk(KERN_DEBUG "msdos_read_super FAIL: can't read inode");

    return NULL;    

  }

  printk0("msdos_read_super(): root inode read");

  insert_inode(in);

  printk0("msdos_read_super(): root inode inserted");

  dcache_unlock(dc);

  printk0("msdos_read_super(): boot sector released");

  printk0("msdos_read_super(): END");

  return sb;

}

/* to remove */

/*

{

  struct qstr str;

  struct inode *in2,*in3,*in4;

  struct dentry *d;

  extern struct inode *msdos_lookup(struct inode *, struct dentry *);

  printk(KERN_DEBUG "---ROOT INODE---\n");

  msdos_dump_inode(in);

  d=get_dentry();

  if (d!=NULL) {

    sys_abort(1234);

  }

  strcpy(d->d_name.name,"BC45");

  d->d_name.nameptr=NULL;

  d->d_op=&msdos_dentry_operations;

  printk(KERN_DEBUG "searching --------------------------\n");

  in2=msdos_lookup(in,d);

  if (in2!=NULL) printk(KERN_DEBUG "found!\n");

  else printk(KERN_DEBUG "not found!\n");

  printk(KERN_DEBUG "---IN2 INODE---\n");

  msdos_dump_inode(in2);

  printk(KERN_DEBUG "searching --------------------------\n");

  strcpy(d->d_name.name,"BIN");

  in3=msdos_lookup(in2,d);

  if (in3!=NULL) printk(KERN_DEBUG "found!\n");

  else printk(KERN_DEBUG "not found!\n");

  printk(KERN_DEBUG "---IN3 INODE---\n");

  msdos_dump_inode(in3);

  printk(KERN_DEBUG "searching --------------------------\n");

  strcpy(d->d_name.name,"pspsp");

  in4=msdos_lookup(in3,d);

  if (in4!=NULL) printk(KERN_DEBUG "found!\n");

  else printk(KERN_DEBUG "not found!\n");

  printk(KERN_DEBUG "---IN4 INODE---\n");

  msdos_dump_inode(in4);

}

*/

/* end to remove */