u-boot fat

wangtianjun-ce

/*
* fat.c
*
* R/O (V)FAT 12/16/32 filesystem implementation by Marcus Sundberg
*
* 2002-07-28 - rjones@nexus-tech.net - ported to ppcboot v1.1.6
* 2003-03-10 - kharris@nexus-tech.net - ported to uboot
*
* See file CREDITS for list of people who contributed to this
* project.
*
* 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
*/
#include <common.h>
#include <config.h>
#include <fat.h>
#include <asm/byteorder.h>
#include <part.h>
#if defined(CONFIG_CMD_FAT)
/*
* Convert a string to lowercase.
*/
static void
downcase(char *str)
{
while (*str != '\0') {
  TOLOWER(*str);
  str++;
}
}
static  block_dev_desc_t *cur_dev = NULL;
static unsigned long part_offset = 0;
static int cur_part = 1;
#define DOS_PART_TBL_OFFSET 0x1be
#define DOS_PART_MAGIC_OFFSET 0x1fe
#define DOS_FS_TYPE_OFFSET 0x36
int disk_read (__u32 startblock, __u32 getsize, __u8 * bufptr)
{
startblock += part_offset;
if (cur_dev == NULL)
  return -1;
if (cur_dev->block_read) {
  return cur_dev->block_read (cur_dev->dev
   , startblock, getsize, (unsigned long *)bufptr);
}
return -1;
}

int
fat_register_device(block_dev_desc_t *dev_desc, int part_no)
{
unsigned char buffer[SECTOR_SIZE];
disk_partition_t info;
if (!dev_desc->block_read)
  return -1;
cur_dev = dev_desc;
/* check if we have a MBR (on floppies we have only a PBR) */
if (dev_desc->block_read (dev_desc->dev, 0, 1, (ulong *) buffer) != 1) {
  printf ("** Can't read from device %d **\n", dev_desc->dev);
  return -1;
}
if (buffer[DOS_PART_MAGIC_OFFSET] != 0x55 ||
  buffer[DOS_PART_MAGIC_OFFSET + 1] != 0xaa) {
  /* no signature found */
  return -1;
}
#if (defined(CONFIG_CMD_IDE) || \
     defined(CONFIG_CMD_SCSI) || \
     defined(CONFIG_CMD_USB) || \
     defined(CONFIG_MMC) || \
     defined(CONFIG_SYSTEMACE) )
/* First we assume, there is a MBR */
if (!get_partition_info (dev_desc, part_no, &info)) {
  part_offset = info.start;
  cur_part = part_no;
} else if (!strncmp((char *)&buffer[DOS_FS_TYPE_OFFSET], "FAT", 3)) {
  /* ok, we assume we are on a PBR only */
  cur_part = 1;
  part_offset = 0;
} else {
  printf ("** Partition %d not valid on device %d **\n",
    part_no, dev_desc->dev);
  return -1;
}
#else
if (!strncmp((char *)&buffer[DOS_FS_TYPE_OFFSET],"FAT",3)) {
  /* ok, we assume we are on a PBR only */
  cur_part = 1;
  part_offset = 0;
  info.start = part_offset;
} else {
  /* FIXME we need to determine the start block of the
   * partition where the DOS FS resides. This can be done
   * by using the get_partition_info routine. For this
   * purpose the libpart must be included.
   */
  part_offset = 32;
  cur_part = 1;
}
#endif
return 0;
}

/*
* Get the first occurence of a directory delimiter ('/' or '\') in a string.
* Return index into string if found, -1 otherwise.
*/
static int
dirdelim(char *str)
{
char *start = str;
while (*str != '\0') {
  if (ISDIRDELIM(*str)) return str - start;
  str++;
}
return -1;
}

/*
* Match volume_info fs_type strings.
* Return 0 on match, -1 otherwise.
*/
static int
compare_sign(char *str1, char *str2)
{
char *end = str1+SIGNLEN;
while (str1 != end) {
  if (*str1 != *str2) {
   return -1;
  }
  str1++;
  str2++;
}
return 0;
}

/*
* Extract zero terminated short name from a directory entry.
*/
static void get_name (dir_entry *dirent, char *s_name)
{
char *ptr;
memcpy (s_name, dirent->name, 8);
s_name[8] = '\0';
ptr = s_name;
while (*ptr && *ptr != ' ')
  ptr++;
if (dirent->ext[0] && dirent->ext[0] != ' ') {
  *ptr = '.';
  ptr++;
  memcpy (ptr, dirent->ext, 3);
  ptr[3] = '\0';
  while (*ptr && *ptr != ' ')
   ptr++;
}
*ptr = '\0';
if (*s_name == DELETED_FLAG)
  *s_name = '\0';
else if (*s_name == aRING)
  *s_name = '?;
downcase (s_name);
}
/*
* Get the entry at index 'entry' in a FAT (12/16/32) table.
* On failure 0x00 is returned.
*/
static __u32
get_fatent(fsdata *mydata, __u32 entry)
{
__u32 bufnum;
__u32 offset;
__u32 ret = 0x00;
switch (mydata->fatsize) {
case 32:
  bufnum = entry / FAT32BUFSIZE;
  offset = entry - bufnum * FAT32BUFSIZE;
  break;
case 16:
  bufnum = entry / FAT16BUFSIZE;
  offset = entry - bufnum * FAT16BUFSIZE;
  break;
case 12:
  bufnum = entry / FAT12BUFSIZE;
  offset = entry - bufnum * FAT12BUFSIZE;
  break;
default:
  /* Unsupported FAT size */
  return ret;
}
/* Read a new block of FAT entries into the cache. */
if (bufnum != mydata->fatbufnum) {
  int getsize = FATBUFSIZE/FS_BLOCK_SIZE;
  __u8 *bufptr = mydata->fatbuf;
  __u32 fatlength = mydata->fatlength;
  __u32 startblock = bufnum * FATBUFBLOCKS;
  fatlength *= SECTOR_SIZE; /* We want it in bytes now */
  startblock += mydata->fat_sect; /* Offset from start of disk */
  if (getsize > fatlength) getsize = fatlength;
  if (disk_read(startblock, getsize, bufptr) < 0) {
   FAT_DPRINT("Error reading FAT blocks\n");
   return ret;
  }
  mydata->fatbufnum = bufnum;
}
/* Get the actual entry from the table */
switch (mydata->fatsize) {
case 32:
  ret = FAT2CPU32(((__u32*)mydata->fatbuf)[offset]);
  break;
case 16:
  ret = FAT2CPU16(((__u16*)mydata->fatbuf)[offset]);
  break;
case 12: {
  __u32 off16 = (offset*3)/4;
  __u16 val1, val2;
  switch (offset & 0x3) {
  case 0:
   ret = FAT2CPU16(((__u16*)mydata->fatbuf)[off16]);
   ret &= 0xfff;
   break;
  case 1:
   val1 = FAT2CPU16(((__u16*)mydata->fatbuf)[off16]);
   val1 &= 0xf000;
   val2 = FAT2CPU16(((__u16*)mydata->fatbuf)[off16+1]);
   val2 &= 0x00ff;
   ret = (val2 << 4) | (val1 >> 12);
   break;
  case 2:
   val1 = FAT2CPU16(((__u16*)mydata->fatbuf)[off16]);
   val1 &= 0xff00;
   val2 = FAT2CPU16(((__u16*)mydata->fatbuf)[off16+1]);
   val2 &= 0x000f;
   ret = (val2 << 8) | (val1 >> 8);
   break;
  case 3:
   ret = FAT2CPU16(((__u16*)mydata->fatbuf)[off16]);;
   ret = (ret & 0xfff0) >> 4;
   break;
  default:
   break;
  }
}
break;
}
FAT_DPRINT("ret: %d, offset: %d\n", ret, offset);
return ret;
}

/*
* Read at most 'size' bytes from the specified cluster into 'buffer'.
* Return 0 on success, -1 otherwise.
*/
static int
get_cluster(fsdata *mydata, __u32 clustnum, __u8 *buffer, unsigned long size)
{
int idx = 0;
__u32 startsect;
if (clustnum > 0) {
  startsect = mydata->data_begin + clustnum*mydata->clust_size;
} else {
  startsect = mydata->rootdir_sect;
}
FAT_DPRINT("gc - clustnum: %d, startsect: %d\n", clustnum, startsect);
if (disk_read(startsect, size/FS_BLOCK_SIZE , buffer) < 0) {
  FAT_DPRINT("Error reading data\n");
  return -1;
}
if(size % FS_BLOCK_SIZE) {
  __u8 tmpbuf[FS_BLOCK_SIZE];
  idx= size/FS_BLOCK_SIZE;
  if (disk_read(startsect + idx, 1, tmpbuf) < 0) {
   FAT_DPRINT("Error reading data\n");
   return -1;
  }
  buffer += idx*FS_BLOCK_SIZE;
  memcpy(buffer, tmpbuf, size % FS_BLOCK_SIZE);
  return 0;
}
return 0;
}

/*
* Read at most 'maxsize' bytes from the file associated with 'dentptr'
* into 'buffer'.
* Return the number of bytes read or -1 on fatal errors.
*/
static long
get_contents(fsdata *mydata, dir_entry *dentptr, __u8 *buffer,
      unsigned long maxsize)
{
unsigned long filesize = FAT2CPU32(dentptr->size), gotsize = 0;
unsigned int bytesperclust = mydata->clust_size * SECTOR_SIZE;
__u32 curclust = START(dentptr);
__u32 endclust, newclust;
unsigned long actsize;
FAT_DPRINT("Filesize: %ld bytes\n", filesize);
if (maxsize > 0 && filesize > maxsize) filesize = maxsize;
FAT_DPRINT("Reading: %ld bytes\n", filesize);
actsize=bytesperclust;
endclust=curclust;
do {
  /* search for consecutive clusters */
  while(actsize < filesize) {
   newclust = get_fatent(mydata, endclust);
   if((newclust -1)!=endclust)
    goto getit;
   if (CHECK_CLUST(newclust, mydata->fatsize)) {
    FAT_DPRINT("curclust: 0x%x\n", newclust);
    FAT_DPRINT("Invalid FAT entry\n");
    return gotsize;
   }
   endclust=newclust;
   actsize+= bytesperclust;
  }
  /* actsize >= file size */
  actsize -= bytesperclust;
  /* get remaining clusters */
  if (get_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
   FAT_ERROR("Error reading cluster\n");
   return -1;
  }
  /* get remaining bytes */
  gotsize += (int)actsize;
  filesize -= actsize;
  buffer += actsize;
  actsize= filesize;
  if (get_cluster(mydata, endclust, buffer, (int)actsize) != 0) {
   FAT_ERROR("Error reading cluster\n");
   return -1;
  }
  gotsize+=actsize;
  return gotsize;
getit:
  if (get_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
   FAT_ERROR("Error reading cluster\n");
   return -1;
  }
  gotsize += (int)actsize;
  filesize -= actsize;
  buffer += actsize;
  curclust = get_fatent(mydata, endclust);
  if (CHECK_CLUST(curclust, mydata->fatsize)) {
   FAT_DPRINT("curclust: 0x%x\n", curclust);
   FAT_ERROR("Invalid FAT entry\n");
   return gotsize;
  }
  actsize=bytesperclust;
  endclust=curclust;
} while (1);
}

#ifdef CONFIG_SUPPORT_VFAT
/*
* Extract the file name information from 'slotptr' into 'l_name',
* starting at l_name[*idx].
* Return 1 if terminator (zero byte) is found, 0 otherwise.
*/
static int
slot2str(dir_slot *slotptr, char *l_name, int *idx)
{
int j;
for (j = 0; j <= 8; j += 2) {
  l_name[*idx] = slotptr->name0_4[j];
  if (l_name[*idx] == 0x00) return 1;
  (*idx)++;
}
for (j = 0; j <= 10; j += 2) {
  l_name[*idx] = slotptr->name5_10[j];
  if (l_name[*idx] == 0x00) return 1;
  (*idx)++;
}
for (j = 0; j <= 2; j += 2) {
  l_name[*idx] = slotptr->name11_12[j];
  if (l_name[*idx] == 0x00) return 1;
  (*idx)++;
}
return 0;
}

/*
* Extract the full long filename starting at 'retdent' (which is really
* a slot) into 'l_name'. If successful also copy the real directory entry
* into 'retdent'
* Return 0 on success, -1 otherwise.
*/
__u8  get_vfatname_block[MAX_CLUSTSIZE];
static int
get_vfatname(fsdata *mydata, int curclust, __u8 *cluster,
      dir_entry *retdent, char *l_name)
{
dir_entry *realdent;
dir_slot  *slotptr = (dir_slot*) retdent;
__u8   *nextclust = cluster + mydata->clust_size * SECTOR_SIZE;
__u8    counter = (slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff;
int idx = 0;
while ((__u8*)slotptr < nextclust) {
  if (counter == 0) break;
  if (((slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff) != counter)
   return -1;
  slotptr++;
  counter--;
}
if ((__u8*)slotptr >= nextclust) {
  dir_slot *slotptr2;
  slotptr--;
  curclust = get_fatent(mydata, curclust);
  if (CHECK_CLUST(curclust, mydata->fatsize)) {
   FAT_DPRINT("curclust: 0x%x\n", curclust);
   FAT_ERROR("Invalid FAT entry\n");
   return -1;
  }
  if (get_cluster(mydata, curclust, get_vfatname_block,
    mydata->clust_size * SECTOR_SIZE) != 0) {
   FAT_DPRINT("Error: reading directory block\n");
   return -1;
  }
  slotptr2 = (dir_slot*) get_vfatname_block;
  while (slotptr2->id > 0x01) {
   slotptr2++;
  }
  /* Save the real directory entry */
  realdent = (dir_entry*)slotptr2 + 1;
  while ((__u8*)slotptr2 >= get_vfatname_block) {
   slot2str(slotptr2, l_name, &idx);
   slotptr2--;
  }
} else {
  /* Save the real directory entry */
  realdent = (dir_entry*)slotptr;
}
do {
  slotptr--;
  if (slot2str(slotptr, l_name, &idx)) break;
} while (!(slotptr->id & LAST_LONG_ENTRY_MASK));
l_name[idx] = '\0';
if (*l_name == DELETED_FLAG) *l_name = '\0';
else if (*l_name == aRING) *l_name = '?;
downcase(l_name);
/* Return the real directory entry */
memcpy(retdent, realdent, sizeof(dir_entry));
return 0;
}

/* Calculate short name checksum */
static __u8
mkcksum(const char *str)
{
int i;
__u8 ret = 0;
for (i = 0; i < 11; i++) {
  ret = (((ret&1)<<7)|((ret&0xfe)>>1)) + str;
}
return ret;
}
#endif

/*
* Get the directory entry associated with 'filename' from the directory
* starting at 'startsect'
*/
__u8 get_dentfromdir_block[MAX_CLUSTSIZE];
static dir_entry *get_dentfromdir (fsdata * mydata, int startsect,
       char *filename, dir_entry * retdent,
       int dols)
{
    __u16 prevcksum = 0xffff;
    __u32 curclust = START (retdent);
    int files = 0, dirs = 0;
    FAT_DPRINT ("get_dentfromdir: %s\n", filename);
    while (1) {
dir_entry *dentptr;
int i;
if (get_cluster (mydata, curclust, get_dentfromdir_block,
   mydata->clust_size * SECTOR_SIZE) != 0) {
     FAT_DPRINT ("Error: reading directory block\n");
     return NULL;
}
dentptr = (dir_entry *) get_dentfromdir_block;
for (i = 0; i < DIRENTSPERCLUST; i++) {
     char s_name[14], l_name[256];
     l_name[0] = '\0';
     if (dentptr->name[0] == DELETED_FLAG) {
      dentptr++;
      continue;
     }
     if ((dentptr->attr & ATTR_VOLUME)) {
#ifdef CONFIG_SUPPORT_VFAT
  if ((dentptr->attr & ATTR_VFAT) &&
      (dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
      prevcksum = ((dir_slot *) dentptr)
       ->alias_checksum;
      get_vfatname (mydata, curclust, get_dentfromdir_block,
      dentptr, l_name);
      if (dols) {
   int isdir = (dentptr->attr & ATTR_DIR);
   char dirc;
   int doit = 0;
   if (isdir) {
       dirs++;
       dirc = '/';
       doit = 1;
   } else {
       dirc = ' ';
       if (l_name[0] != 0) {
    files++;
    doit = 1;
       }
   }
   if (doit) {
       if (dirc == ' ') {
    printf (" %8ld   %s%c\n",
     (long) FAT2CPU32 (dentptr->size),
     l_name, dirc);
       } else {
    printf ("            %s%c\n", l_name, dirc);
       }
   }
   dentptr++;
   continue;
      }
      FAT_DPRINT ("vfatname: |%s|\n", l_name);
  } else
#endif
  {
      /* Volume label or VFAT entry */
      dentptr++;
      continue;
  }
     }
     if (dentptr->name[0] == 0) {
  if (dols) {
      printf ("\n%d file(s), %d dir(s)\n\n", files, dirs);
  }
  FAT_DPRINT ("Dentname == NULL - %d\n", i);
  return NULL;
     }
#ifdef CONFIG_SUPPORT_VFAT
     if (dols && mkcksum (dentptr->name) == prevcksum) {
  dentptr++;
  continue;
     }
#endif
     get_name (dentptr, s_name);
     if (dols) {
  int isdir = (dentptr->attr & ATTR_DIR);
  char dirc;
  int doit = 0;
  if (isdir) {
      dirs++;
      dirc = '/';
      doit = 1;
  } else {
      dirc = ' ';
      if (s_name[0] != 0) {
   files++;
   doit = 1;
      }
  }
  if (doit) {
      if (dirc == ' ') {
   printf (" %8ld   %s%c\n",
    (long) FAT2CPU32 (dentptr->size), s_name,
    dirc);
      } else {
   printf ("            %s%c\n", s_name, dirc);
      }
  }
  dentptr++;
  continue;
     }
     if (strcmp (filename, s_name) && strcmp (filename, l_name)) {
  FAT_DPRINT ("Mismatch: |%s|%s|\n", s_name, l_name);
  dentptr++;
  continue;
     }
     memcpy (retdent, dentptr, sizeof (dir_entry));
     FAT_DPRINT ("DentName: %s", s_name);
     FAT_DPRINT (", start: 0x%x", START (dentptr));
     FAT_DPRINT (", size:  0x%x %s\n",
   FAT2CPU32 (dentptr->size),
   (dentptr->attr & ATTR_DIR) ? "(DIR)" : "");
     return retdent;
}
curclust = get_fatent (mydata, curclust);
if (CHECK_CLUST(curclust, mydata->fatsize)) {
     FAT_DPRINT ("curclust: 0x%x\n", curclust);
     FAT_ERROR ("Invalid FAT entry\n");
     return NULL;
}
    }
    return NULL;
}

/*
* Read boot sector and volume info from a FAT filesystem
*/
static int
read_bootsectandvi(boot_sector *bs, volume_info *volinfo, int *fatsize)
{
__u8 block[FS_BLOCK_SIZE];
volume_info *vistart;
if (disk_read(0, 1, block) < 0) {
  FAT_DPRINT("Error: reading block\n");
  return -1;
}
memcpy(bs, block, sizeof(boot_sector));
bs->reserved = FAT2CPU16(bs->reserved);
bs->fat_length = FAT2CPU16(bs->fat_length);
bs->secs_track = FAT2CPU16(bs->secs_track);
bs->heads = FAT2CPU16(bs->heads);
#if 0 /* UNUSED */
bs->hidden = FAT2CPU32(bs->hidden);
#endif
bs->total_sect = FAT2CPU32(bs->total_sect);
/* FAT32 entries */
if (bs->fat_length == 0) {
  /* Assume FAT32 */
  bs->fat32_length = FAT2CPU32(bs->fat32_length);
  bs->flags  = FAT2CPU16(bs->flags);
  bs->root_cluster = FAT2CPU32(bs->root_cluster);
  bs->info_sector  = FAT2CPU16(bs->info_sector);
  bs->backup_boot  = FAT2CPU16(bs->backup_boot);
  vistart = (volume_info*) (block + sizeof(boot_sector));
  *fatsize = 32;
} else {
  vistart = (volume_info*) &(bs->fat32_length);
  *fatsize = 0;
}
memcpy(volinfo, vistart, sizeof(volume_info));
/* Terminate fs_type string. Writing past the end of vistart
    is ok - it's just the buffer. */
vistart->fs_type[8] = '\0';
if (*fatsize == 32) {
  if (compare_sign(FAT32_SIGN, vistart->fs_type) == 0) {
   return 0;
  }
} else {
  if (compare_sign(FAT12_SIGN, vistart->fs_type) == 0) {
   *fatsize = 12;
   return 0;
  }
  if (compare_sign(FAT16_SIGN, vistart->fs_type) == 0) {
   *fatsize = 16;
   return 0;
  }
}
FAT_DPRINT("Error: broken fs_type sign\n");
return -1;
}

__u8 do_fat_read_block[MAX_CLUSTSIZE];  /* Block buffer */
long
do_fat_read (const char *filename, void *buffer, unsigned long maxsize,
      int dols)
{
#if CONFIG_NIOS /* NIOS CPU cannot access big automatic arrays */
    static
#endif
    char fnamecopy[2048];
    boot_sector bs;
    volume_info volinfo;
    fsdata datablock;
    fsdata *mydata = &datablock;
    dir_entry *dentptr;
    __u16 prevcksum = 0xffff;
    char *subname = "";
    int rootdir_size, cursect;
    int idx, isdir = 0;
    int files = 0, dirs = 0;
    long ret = 0;
    int firsttime;
    if (read_bootsectandvi (&bs, &volinfo, &mydata->fatsize)) {
FAT_DPRINT ("Error: reading boot sector\n");
return -1;
    }
    if (mydata->fatsize == 32) {
mydata->fatlength = bs.fat32_length;
    } else {
mydata->fatlength = bs.fat_length;
    }
    mydata->fat_sect = bs.reserved;
    cursect = mydata->rootdir_sect
     = mydata->fat_sect + mydata->fatlength * bs.fats;
    mydata->clust_size = bs.cluster_size;
    if (mydata->fatsize == 32) {
rootdir_size = mydata->clust_size;
mydata->data_begin = mydata->rootdir_sect   /* + rootdir_size */
  - (mydata->clust_size * 2);
    } else {
rootdir_size = ((bs.dir_entries[1] * (int) 256 + bs.dir_entries[0])
   * sizeof (dir_entry)) / SECTOR_SIZE;
mydata->data_begin = mydata->rootdir_sect + rootdir_size
  - (mydata->clust_size * 2);
    }
    mydata->fatbufnum = -1;
    FAT_DPRINT ("FAT%d, fatlength: %d\n", mydata->fatsize,
  mydata->fatlength);
    FAT_DPRINT ("Rootdir begins at sector: %d, offset: %x, size: %d\n"
  "Data begins at: %d\n",
  mydata->rootdir_sect, mydata->rootdir_sect * SECTOR_SIZE,
  rootdir_size, mydata->data_begin);
    FAT_DPRINT ("Cluster size: %d\n", mydata->clust_size);
    /* "cwd" is always the root... */
    while (ISDIRDELIM (*filename))
filename++;
    /* Make a copy of the filename and convert it to lowercase */
    strcpy (fnamecopy, filename);
    downcase (fnamecopy);
    if (*fnamecopy == '\0') {
if (!dols)
     return -1;
dols = LS_ROOT;
    } else if ((idx = dirdelim (fnamecopy)) >= 0) {
isdir = 1;
fnamecopy[idx] = '\0';
subname = fnamecopy + idx + 1;
/* Handle multiple delimiters */
while (ISDIRDELIM (*subname))
     subname++;
    } else if (dols) {
isdir = 1;
    }
    while (1) {
int i;
if (disk_read (cursect, mydata->clust_size, do_fat_read_block) < 0) {
     FAT_DPRINT ("Error: reading rootdir block\n");
     return -1;
}
dentptr = (dir_entry *) do_fat_read_block;
for (i = 0; i < DIRENTSPERBLOCK; i++) {
     char s_name[14], l_name[256];
     l_name[0] = '\0';
     if ((dentptr->attr & ATTR_VOLUME)) {
#ifdef CONFIG_SUPPORT_VFAT
  if ((dentptr->attr & ATTR_VFAT) &&
      (dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
      prevcksum = ((dir_slot *) dentptr)->alias_checksum;
      get_vfatname (mydata, 0, do_fat_read_block, dentptr, l_name);
      if (dols == LS_ROOT) {
   int isdir = (dentptr->attr & ATTR_DIR);
   char dirc;
   int doit = 0;
   if (isdir) {
       dirs++;
       dirc = '/';
       doit = 1;
   } else {
       dirc = ' ';
       if (l_name[0] != 0) {
    files++;
    doit = 1;
       }
   }
   if (doit) {
       if (dirc == ' ') {
    printf (" %8ld   %s%c\n",
     (long) FAT2CPU32 (dentptr->size),
     l_name, dirc);
       } else {
    printf ("            %s%c\n", l_name, dirc);
       }
   }
   dentptr++;
   continue;
      }
      FAT_DPRINT ("Rootvfatname: |%s|\n", l_name);
  } else
#endif
  {
      /* Volume label or VFAT entry */
      dentptr++;
      continue;
  }
     } else if (dentptr->name[0] == 0) {
  FAT_DPRINT ("RootDentname == NULL - %d\n", i);
  if (dols == LS_ROOT) {
      printf ("\n%d file(s), %d dir(s)\n\n", files, dirs);
      return 0;
  }
  return -1;
     }
#ifdef CONFIG_SUPPORT_VFAT
     else if (dols == LS_ROOT
       && mkcksum (dentptr->name) == prevcksum) {
  dentptr++;
  continue;
     }
#endif
     get_name (dentptr, s_name);
     if (dols == LS_ROOT) {
  int isdir = (dentptr->attr & ATTR_DIR);
  char dirc;
  int doit = 0;
  if (isdir) {
      dirc = '/';
      if (s_name[0] != 0) {
   dirs++;
   doit = 1;
      }
  } else {
      dirc = ' ';
      if (s_name[0] != 0) {
   files++;
   doit = 1;
      }
  }
  if (doit) {
      if (dirc == ' ') {
   printf (" %8ld   %s%c\n",
    (long) FAT2CPU32 (dentptr->size), s_name,
    dirc);
      } else {
   printf ("            %s%c\n", s_name, dirc);
      }
  }
  dentptr++;
  continue;
     }
     if (strcmp (fnamecopy, s_name) && strcmp (fnamecopy, l_name)) {
  FAT_DPRINT ("RootMismatch: |%s|%s|\n", s_name, l_name);
  dentptr++;
  continue;
     }
     if (isdir && !(dentptr->attr & ATTR_DIR))
  return -1;
     FAT_DPRINT ("RootName: %s", s_name);
     FAT_DPRINT (", start: 0x%x", START (dentptr));
     FAT_DPRINT (", size:  0x%x %s\n",
   FAT2CPU32 (dentptr->size), isdir ? "(DIR)" : "");
     goto rootdir_done;  /* We got a match */
}
cursect++;
    }
  rootdir_done:
    firsttime = 1;
    while (isdir) {
int startsect = mydata->data_begin
  + START (dentptr) * mydata->clust_size;
dir_entry dent;
char *nextname = NULL;
dent = *dentptr;
dentptr = &dent;
idx = dirdelim (subname);
if (idx >= 0) {
     subname[idx] = '\0';
     nextname = subname + idx + 1;
     /* Handle multiple delimiters */
     while (ISDIRDELIM (*nextname))
  nextname++;
     if (dols && *nextname == '\0')
  firsttime = 0;
} else {
     if (dols && firsttime) {
  firsttime = 0;
     } else {
  isdir = 0;
     }
}
if (get_dentfromdir (mydata, startsect, subname, dentptr,
        isdir ? 0 : dols) == NULL) {
     if (dols && !isdir)
  return 0;
     return -1;
}
if (idx >= 0) {
     if (!(dentptr->attr & ATTR_DIR))
  return -1;
     subname = nextname;
}
    }
    ret = get_contents (mydata, dentptr, buffer, maxsize);
    FAT_DPRINT ("Size: %d, got: %ld\n", FAT2CPU32 (dentptr->size), ret);
    return ret;
}

int
file_fat_detectfs(void)
{
boot_sector bs;
volume_info volinfo;
int  fatsize;
char vol_label[12];
if(cur_dev==NULL) {
  printf("No current device\n");
  return 1;
}
#if defined(CONFIG_CMD_IDE) || \
    defined(CONFIG_CMD_SCSI) || \
    defined(CONFIG_CMD_USB) || \
    defined(CONFIG_MMC)
printf("Interface:  ");
switch(cur_dev->if_type) {
  case IF_TYPE_IDE : printf("IDE"); break;
  case IF_TYPE_SCSI : printf("SCSI"); break;
  case IF_TYPE_ATAPI : printf("ATAPI"); break;
  case IF_TYPE_USB : printf("USB"); break;
  case IF_TYPE_DOC : printf("DOC"); break;
  case IF_TYPE_MMC : printf("MMC"); break;
  default :  printf("Unknown");
}
printf("\n  Device %d: ",cur_dev->dev);
dev_print(cur_dev);
#endif
if(read_bootsectandvi(&bs, &volinfo, &fatsize)) {
  printf("\nNo valid FAT fs found\n");
  return 1;
}
memcpy (vol_label, volinfo.volume_label, 11);
vol_label[11] = '\0';
volinfo.fs_type[5]='\0';
printf(&quotartition %d: Filesystem: %s \"%s\"\n"
   ,cur_part,volinfo.fs_type,vol_label);
return 0;
}

int
file_fat_ls(const char *dir)
{
return do_fat_read(dir, NULL, 0, LS_YES);
}

long
file_fat_read(const char *filename, void *buffer, unsigned long maxsize)
{
printf("reading %s\n",filename);
return do_fat_read(filename, buffer, maxsize, LS_NO);
}
#endif

hexioamiao

好长啊

yfchen1003

什么东东

longxuekai

哦，这样的啊

io357

代码的用途是什么？