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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_i.c,v 1.2 2002-10-28 08:24:43 pj Exp $

 *

 * File:        $File$

 * Revision:    $Revision: 1.2 $

 * Last update: $Date: 2002-10-28 08:24:43 $

 */

#include <fs/types.h>

#include <fs/const.h>

#include <fs/stat.h>

#include <fs/assert.h>

#include "dcache.h"

#include "fs.h"

#include "msdos.h"

#include "msdos/msdos.h"

#include "debug.h"

/*

 * local DEBUG

 */

#define DEBUG_ADDCLUSTER KERN_DEBUG

#undef DEBUG_ADDCLUSTER

#define DEBUG_ADDCLUSTER_EXTRA KERN_DEBUG

#undef DEBUG_ADDCLUSTER_EXTRA

/**/

#ifdef DEBUG_ADDCLUSTER

#define printd0(fmt,args...) \

        if (debug_info) printk(DEBUG_ADDCLUSTER fmt,##args)

#else

#define printd0(fmt,args...)

#endif

#if defined(DEBUG_ADDCLUSTER)&&defined(DEBUG_ADDCLUSTER_EXTRA)

#define printd1(fmt,args...) \

        if (debug_info) printk(DEBUG_ADDCLUSTER fmt,##args)

#else

#define printd1(fmt,args...)

#endif

/*

 *

 */

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

{

  static char str[13];

  _assert(n<13);

  memcpy(str,s,n);

  str[n]='\0';

  return str;

}

void msdos_dump_direntry(struct directoryentry *ptr)

{

  printk(KERN_DEBUG "status    : 0x%02x",(int)ptr->name[0]);

  printk(KERN_DEBUG "filename  : '%s'",chr2str(ptr->name,8));

  printk(KERN_DEBUG "ext       : '%s'",chr2str(ptr->ext,3));

  printk(KERN_DEBUG "attribute : 0x%02x",ptr->attribute);

  printk(KERN_DEBUG "cluster   : %04x",ptr->cluster);

  printk(KERN_DEBUG "size      : %li",(long)ptr->size);

  printk(KERN_DEBUG "time      : %li",(long)ptr->time);

}

/* what is the logical sector of a cluster into the fat */

static __inline __uint32_t __cluster2lsect(struct super_block *sb,

                                           __uint16_t cluster)

{

  return MSDOS_SB(sb).lfat+((__uint32_t)cluster*2)/SECTORSIZE;

}

/* what is the offset of a cluster into the fat */

static __inline __uint32_t __cluster2offs(__uint16_t cluster)

{

  return ((__uint32_t)cluster*2)%SECTORSIZE;

}

/**/

static __inline__ void __lock(struct super_block *sb,

                                dcache_t *buf[],

                                __uint32_t lsect)

{

  _assert(buf[0]==NULL);

  buf[0]=dcache_lock(sb->sb_dev,lsect);

}

static __inline__ void __unlock(struct super_block *sb,

                                dcache_t *buf[])

{

  _assert(buf[0]!=NULL);

  dcache_unlock(buf[0]);

  buf[0]=NULL;

}

static __inline__ void __acquire(struct super_block *sb,

                                dcache_t *buf[],

                                __uint32_t lsect)

{

  int i=0;

  _assert(buf[0]==NULL);

  _assert(MSDOS_SB(sb).nfat<=MAXFATS);

  for (i=0;i<MSDOS_SB(sb).nfat;i++) {

    buf[i]=dcache_acquire(sb->sb_dev,lsect);

    _assert(buf[i]!=NULL);

    lsect+=MSDOS_SB(sb).spf;

  }

}

static __inline__ void __release(struct super_block *sb,

                                dcache_t *buf[])

{

  int i;

  _assert(buf[0]!=NULL);

  for (i=MSDOS_SB(sb).nfat-1;i>=0;i--) {

    _assert(buf[i]!=NULL);

    dcache_release(buf[i]);

  }

  buf[0]=NULL;

}

static __inline__ __uint16_t __getcluster(struct super_block *sb,

                                          dcache_t *buf[],

                                          __uint16_t offs)

{

  _assert(buf[0]!=NULL);

  return *(__uint16_t*)(buf[0]->buffer+offs);  

}

static __inline__ void __setcluster(struct super_block *sb,

                                    dcache_t *buf[],

                                    __uint16_t offs,

                                    __uint16_t val)

{

  int i;

  _assert(buf[0]!=NULL);

  for (i=0;i<MSDOS_SB(sb).nfat;i++) {

    _assert(buf[i]!=NULL);

    *(__uint16_t*)(buf[i]->buffer+offs)=val;

    dcache_dirty(buf[i]);

    dcache_skipwt(buf[i]);

  }

}

/*

 *

 */

__uint16_t msdos_nextcluster(struct super_block *sb, __uint16_t cluster)

{

  dcache_t *buf[MAXFATS];

  __uint32_t lsect;

  __uint16_t  offs;

  __uint16_t  ret;

  buf[0]=NULL;

  lsect=__cluster2lsect(sb,cluster);

  offs=__cluster2offs(cluster);

  __lock(sb,buf,lsect);

  ret=__getcluster(sb,buf,offs);  

  __unlock(sb,buf);

  return ret;

}

void msdos_freecluster(struct super_block *sb, __uint16_t cluster)

{

  dcache_t   *buf[MAXFATS];

  __uint32_t lsect;

  __uint16_t offs;

  buf[0]=NULL;

  lsect=__cluster2lsect(sb,cluster);

  offs=__cluster2offs(cluster);

  __acquire(sb,buf,lsect);

  _assert(__getcluster(sb,buf,offs)!=FREECLUSTER);

  __setcluster(sb,buf,offs,FREECLUSTER);

  __release(sb,buf);

  return;

}

void msdos_lastcluster(struct super_block *sb, __uint16_t cluster)

{

  dcache_t   *buf[MAXFATS];

  __uint32_t lsect;

  __uint16_t offs;

  buf[0]=NULL;

  lsect=__cluster2lsect(sb,cluster);

  offs=__cluster2offs(cluster);

  __acquire(sb,buf,lsect);

  //_assert(__getcluster(sb,buf,offs)==FREECLUSTER);

  _assert(__getcluster(sb,buf,offs)!=LASTCLUSTER);

  __setcluster(sb,buf,offs,LASTCLUSTER);

  __release(sb,buf);

  return;

}

__uint16_t msdos_addcluster(struct super_block *sb, __uint16_t lacluster)

{

  dcache_t   *buf[MAXFATS];

  __uint32_t lsect;

  __uint16_t offs;

  __uint32_t olsect;

  __uint16_t cluster,stcluster;

  printd0("msdos_addcluster START");

  stcluster=cluster=MSDOS_SB(sb).stclust;  

  olsect=0;

  buf[0]=NULL;

  printd0("searching from cluster 0x%04lx",(long)stcluster);

  for (;;) {

    lsect=__cluster2lsect(sb,cluster);

    offs=__cluster2offs(cluster);

    if (lsect>=MSDOS_SB(sb).lroot) {

      cluster=STARTCLUSTER;

      lsect=__cluster2lsect(sb,cluster);

      offs=__cluster2offs(cluster);

      _assert(lsect<MSDOS_SB(sb).lroot);

    }

    if (lsect!=olsect) {

      if (buf[0]!=NULL) __release(sb,buf);

      __acquire(sb,buf,lsect);

      printd1("read sector %li",(long)lsect);

      olsect=lsect;

    }

    if (__getcluster(sb,buf,offs)==FREECLUSTER) {

      printd0("cluster 0x%04lx (into FAT lsect: %li) added to 0x%04lx",

              (long)cluster,(long)lsect,(long)lacluster);

      MSDOS_SB(sb).stclust=cluster;

      __setcluster(sb,buf,offs,LASTCLUSTER);

      /* if lacluster is not a cluster we do NOT change the FAT table!*/

      if (lacluster==NO_CLUSTER) break;

      __release(sb,buf);

      lsect=__cluster2lsect(sb,lacluster);

      offs=__cluster2offs(lacluster);

      __acquire(sb,buf,lsect);

      _assert(__getcluster(sb,buf,offs)==LASTCLUSTER);

      __setcluster(sb,buf,offs,cluster);

      break;

    }

    cluster++;

    if (cluster==stcluster) {

      cluster=NO_CLUSTER;

      break;

    }

  }  

  __release(sb,buf);

  printd0("msdos_addcluster END");

  return cluster;

}

void msdos_freeclusterchain(struct super_block *sb, __uint16_t cluster)

{

  dcache_t *buf[MAXFATS];

  __uint32_t  lsect;

  __uint16_t  offs;

  __uint32_t  olsect;

  buf[0]=NULL;

  olsect=0;

  for (;;) {

    lsect=__cluster2lsect(sb,cluster);

    offs=__cluster2offs(cluster);

    if (lsect!=olsect) {

      if (buf[0]!=NULL) __release(sb,buf);

      __acquire(sb,buf,lsect);

      olsect=lsect;

    }

    cluster=__getcluster(sb,buf,offs);

    _assert(cluster!=FREECLUSTER);

    __setcluster(sb,buf,offs,FREECLUSTER);

    if (cluster==LASTCLUSTER) break;

  }  

  __release(sb,buf);  

  return;

}

/*

 *

 */

/* from FS specific filename into 'de' to the general filename into 'str' */

int msdos_formatname(struct directoryentry *de, struct qstr *str)

{  

  char *s=str->name;

  char *ptr=de->name;

  int i;

  if (*ptr==0x05) *s++=0xed;

  else *s++=*ptr++;

  i=sizeof(de->name)-1;

  while (i-->0) {

    if (*ptr==' '||*ptr=='\0') break;

    *s++=*ptr++;

  }

  if (de->ext[0]!=' '&&de->ext[0]!='\0') {

    *s++='.';

    ptr=de->ext;

    i=sizeof(de->ext);

    while (i-->0) {

      if (*ptr==' '||*ptr=='\0') break;

      *s++=*ptr++;

    }

  }

  *s++='\0';

  str->nameptr=NULL;

  return 0;

}

/* all filename are traslated in upper case */

#define _up(x) (((x)>='a'&&(x)<='z')?(x)-'a'+'A':(x))

/* from the general filename into 'str' to FS specific filename into 'de' */

int msdos_deformatname(struct qstr *str,struct directoryentry *de)

{

  char *s=QSTRNAME(str);

  char *ptr=de->name;

  int i;

  memset(de->name,' ',sizeof(de->name));

  memset(de->ext,' ',sizeof(de->ext));

  i=0;

  for (i=0;i<sizeof(de->name);i++,s++,ptr++) {    

    if (*s=='.'||*s=='\0') break;

    *ptr=_up(*s);

  }

  if (*s=='\0') return 0;

  while (*s!='.') {

    if (*s=='\0') return 0;

    s++;

  }

  ptr=de->ext;

  s++;

  for (i=0;i<sizeof(de->name);i++,s++,ptr++) {    

    if (*s=='.'||*s=='\0') break;

    *ptr=_up(*s);

  }

  return 0;

}

static int msdos_dummy_truncate(struct inode *in, __off_t len)

{

  return -1;

}

static int msdos_truncate(struct inode *in, __off_t len)

{

  int numclusters;

  int cl,pcl;

  if (len>=in->i_st.st_size) return 0;

  if (len==0) {

    msdos_freeclusterchain(in->i_sb,MSDOS_I(in).scluster);

    MSDOS_I(in).scluster=FREE_CLUSTER;

    in->i_st.st_size=0;

    in->i_dirty=1;

    return 0;

  }

  numclusters=(len-1)/(MSDOS_SB(in->i_sb).spc*(long)SECTORSIZE)+1;

  /* walk on cluster chain */

  pcl=-1;

  cl=MSDOS_I(in).scluster;  

  while (numclusters-->0) {

    pcl=cl;

    cl=msdos_nextcluster(in->i_sb,cl);

  }

  if (cl!=LASTCLUSTER) {

    _assert(pcl!=-1);

    msdos_lastcluster(in->i_sb,pcl);

    msdos_freeclusterchain(in->i_sb,cl);

  }

  in->i_st.st_size=len;

  in->i_dirty=1;

  return 0;

}

/* msdos_create_inode() and msdos_lockup() are very similar */

/* they should be share code */

static struct inode *msdos_create_inode(struct inode *in, struct dentry *den)

{

  struct inode *in2;

  struct directoryentry *de;

  dcache_t *buf;

  __uint32_t lsect;

  __uint16_t  ldisk;

  __uint16_t cluster,prevcluster;

  int flagroot;

  int spc;

  int i,j;

  int res;

  /* for safety ;-) */

  if (!__S_ISDIR(in->i_st.st_mode)) return NULL;

  flagroot=(((in->i_st.st_ino&CLUSTER_MASK)>>CLUSTER_SHIFT)==ROOT_CLUSTER);

  if (flagroot) {

    cluster=SPECIAL_CLUSTER;

    lsect=MSDOS_SB(in->i_sb).lroot;

    spc=MSDOS_SB(in->i_sb).rootsect;

  } else {

    cluster=MSDOS_I(in).scluster;

    lsect=msdos_cluster2sector(in,cluster);

    _assert(lsect!=(__uint32_t)-1);

    spc=MSDOS_SB(in->i_sb).spc;

  }

  printk1("msdos create inode: start directory scanning");

  ldisk=in->i_sb->sb_dev;

  /* for every cluster... */

  for (;;) {

    /* for every sectors... */

    for (j=0;j<spc;j++,lsect++) {

      buf=dcache_acquire(ldisk,lsect);

      printk1("msdos create inode: logical sector %li",(long)lsect);

      if (buf==NULL) {

        printk1("msdos create inode: can't read sector");

        return NULL;

      }

      /* for every directory entry... */

      de=(struct directoryentry *)(buf->buffer);

      for (i=0;i<SECTORSIZE/DIRENTRYSIZE;i++) {

        if (msdos_isfreeentry(de+i)) {

          printk1("msdos create inode: found free entry");

          in2=catch_inode();

          printk1("-------------------");        

          if (in2==NULL) {

            printk1("msdos create inode: can't get free inode!");

            dcache_release(buf);

            return NULL;           

          }

          in2->i_sb=in->i_sb;

          in2->i_st.st_ino=CLUOFF2INODE(cluster,j*SECTORSIZE/DIRENTRYSIZE+i);

          res=in2->i_sb->sb_op->init_inode(in2);

          if (res!=0) {

            printk1("msdos create inode: can't init inode!");

            free_inode(in2);

            dcache_release(buf);

            return NULL;    

          }

          msdos_markentrybusy(de+i);

          msdos_deformatname(&den->d_name,de+i);

          dcache_dirty(buf);

          dcache_release(buf);

          return in2;

        }

      } /* end directory entry loop */

      dcache_release(buf);

      printk1("msdos create inode: next sector");

    } /* end sector loop */

    if (flagroot) {

      printk1("msdos create inode : no free slot (can't add one)");

      return NULL;

    }

    cluster=msdos_nextcluster(in->i_sb,prevcluster=cluster);

    if (cluster==LASTCLUSTER) {

      printk1("msdos create inode: no free slot (try to add one)");

      cluster=msdos_addcluster(in->i_sb,prevcluster);

      if (cluster==NO_CLUSTER) {

        printk1("msdos create inode: can't add cluster");

        return NULL;

      }

      /* zeroing the new cluster */

      lsect=msdos_cluster2sector(in,cluster);

      _assert(lsect!=(__uint32_t)-1);

      for (j=0;j<spc;j++,lsect++) {

        buf=dcache_acquire(ldisk,lsect);

        _assert(buf!=NULL);

        memset(buf->buffer,0,SECTORSIZE);

        dcache_dirty(buf);

        dcache_release(buf);

      }

      printk1("msdos create inode: added cluster");

    }

    lsect=msdos_cluster2sector(in,cluster);

    _assert(lsect!=(__uint32_t)-1);

    printk1("msdos create inode: next cluster");

  } /* end cluster loop */

}

static struct inode *msdos_lookup(struct inode *in, struct dentry *den)

{

  struct inode *in2;

  struct directoryentry *de;

  struct qstr str;

  dcache_t *buf;

  __uint32_t lsect;

  __uint16_t  ldisk;

  __uint16_t cluster;

  int flagroot;

  int spc;

  int i,j;

  int res;

  printk1("msdos lookup: START for %s",QSTRNAME(&(den->d_name)));

  /* for safety ;-) */

  if (!__S_ISDIR(in->i_st.st_mode)) return NULL;

  printk1("msdos lookup: is directory... ok");

  flagroot=(((in->i_st.st_ino&CLUSTER_MASK)>>CLUSTER_SHIFT)==ROOT_CLUSTER);

  if (flagroot) {

    cluster=SPECIAL_CLUSTER;

    lsect=MSDOS_SB(in->i_sb).lroot;

    spc=MSDOS_SB(in->i_sb).rootsect;

  } else {

    cluster=MSDOS_I(in).scluster;

    lsect=msdos_cluster2sector(in,cluster);

    _assert(lsect!=(__uint32_t)-1);

    spc=MSDOS_SB(in->i_sb).spc;

  }

  printk1("msdos lookup: start directory scanning");

  ldisk=in->i_sb->sb_dev;

  /* for every cluster... */

  for (;;) {

    /* for every sectors... */

    for (j=0;j<spc;j++,lsect++) {

      buf=dcache_lock(ldisk,lsect);

      printk1("msdos lookup: logical sector %li",(long)lsect);

      if (buf==NULL) {

        printk1("msdos lookup: can't read sector");

        return NULL;

      }

      /* for every directory entry... */

      de=(struct directoryentry *)(buf->buffer);

      for (i=0;i<SECTORSIZE/DIRENTRYSIZE;i++) {

        if (msdos_islastentry(de+i)) {

          /* last entry... not found! */

          dcache_unlock(buf);

          printk1("msdos lookup: NOT found");

          return NULL;

        }

        /* if it' an invalid entry (not a regular file or directory entry) */

        if (msdos_isunvalidentry(de+i)) continue;

        /* extract name */

        res=msdos_formatname(de+i,&str);

        if (res!=0) {

          dcache_unlock(buf);

          printk1("msdos lookup: can't extract filename");

          return NULL;

        }

        printk1e("msdos lookup: filename '%s'",QSTRNAME(&str));

        /* compare name and if found... */

        if (den->d_op->d_compare(den,&den->d_name,&str)==0) {

          printk1("msdos lookup: found");        

          in2=catch_inode();

          printk1("-------------------");

          if (in2==NULL) {

            printk1("msdos lookup: can't get free inode!");

            dcache_unlock(buf);

            return NULL;    

          }

          in2->i_sb=in->i_sb;

          in2->i_st.st_ino=CLUOFF2INODE(cluster,j*SECTORSIZE/DIRENTRYSIZE+i);

          res=in2->i_sb->sb_op->read_inode(in2);

          if (res!=0) {

            printk1("msdos lookup: can't read inode!");

            free_inode(in2);

            dcache_unlock(buf);

            return NULL;    

          }

          dcache_unlock(buf);

          return in2;

        }

      } /* end directory entry loop */

      dcache_unlock(buf);

      printk1("msdos lookup: next sector");

    } /* end sector loop */

    if (flagroot) {

      printk1("msdos lookup: NOT found (no other entry into root dir)");

      return NULL;

    }

    cluster=msdos_nextcluster(in->i_sb,cluster);

    if (cluster==0||cluster>=0xfff0) {

      printk1("msdos lookup: NOT found (end cluster)");  

      return NULL;

    }

    lsect=msdos_cluster2sector(in,cluster);

    _assert(lsect!=(__uint32_t)-1);

    printk1("msdos lookup: next cluster");

  } /* end cluster loop */

}

static int msdos_dummy_unlink(struct dentry *d)

{

  return EROFS;

}

static int msdos_unlink(struct dentry *d)

{

  printkd("msdos_unlink: START");

  /* only one dentry can own this inode... */

  _assert(d->d_inode->i_dlink==1);

  /* nothing to do */

  /* update link count */

  d->d_inode->i_st.st_nlink--;

  _assert(d->d_inode->i_st.st_nlink==0);

  printkd("msdos_unlink: END");

  return 0;  

}

static void msdos_destroy(struct inode *in)

{

  msdos_truncate(in,0);

  return;

}

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

struct inode_operations msdos_inode_ro_operations={

  &msdos_file_ro_operations,

  msdos_create_inode,

  msdos_lookup,

  msdos_dummy_unlink,

  msdos_destroy,

  msdos_dummy_truncate

};

struct inode_operations msdos_inode_rw_operations={

  &msdos_file_rw_operations,

  msdos_create_inode,

  msdos_lookup,

  msdos_unlink,

  msdos_destroy,

  msdos_truncate

};

/*

 *

 * for inlines

 *

 */

int msdos_islastentry(struct directoryentry *de)

{

  return (*((de)->name)==LASTENTRYCHAR);

}

int msdos_isunvalidentry(struct directoryentry *de)

{

  return (*((de)->name)==ERASEDENTRYCHAR)||

    ((de)->attribute&ATTR_VOLUME)||

    (msdos_islastentry(de));

}