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nuttx/fs/fs_fat32util.c
patacongo e85f4186a4 Support for open of FAT fs 
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@230 42af7a65-404d-4744-a932-0658087f49c3
2007-05-19 21:30:57 +00:00

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/****************************************************************************
* fs_fat32util.c
*
* Copyright (C) 2007 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name Gregory Nutt nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <semaphore.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/fs.h>
#include "fs_internal.h"
#include "fs_fat32.h"
#if CONFIG_FS_FAT
/****************************************************************************
* Definitions
****************************************************************************/
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/****************************************************************************
* Private Variables
****************************************************************************/
/****************************************************************************
* Public Variables
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: fat_hwread
*
* Desciption: Read the specified sector into the sector buffer
*
****************************************************************************/
static int fat_hwread(struct fat_mountpt_s *fs, ubyte *buffer,
size_t sector, unsigned int nsectors)
{
int ret = -ENODEV;
if (fs && fs->fs_blkdriver )
{
struct inode *inode = fs->fs_blkdriver;
if (inode && inode->u.i_bops && inode->u.i_bops->read)
{
ssize_t nSectorsRead = inode->u.i_bops->read(inode, buffer,
sector, nsectors);
if (nSectorsRead == nsectors)
{
ret = OK;
}
else if (nSectorsRead < 0)
{
ret = nSectorsRead;
}
}
}
return ret;
}
/****************************************************************************
* Name: fat_hwwrite
*
* Desciption: Write the sector buffer to the specified sector
*
****************************************************************************/
static int fat_hwwrite(struct fat_mountpt_s *fs, ubyte *buffer,
size_t sector, unsigned int nsectors)
{
int ret = -ENODEV;
if (fs && fs->fs_blkdriver )
{
struct inode *inode = fs->fs_blkdriver;
if (inode && inode->u.i_bops && inode->u.i_bops->write)
{
ssize_t nSectorsWritten =
inode->u.i_bops->write(inode, buffer, sector, nsectors);
if (nSectorsWritten == nsectors)
{
ret = OK;
}
else if (nSectorsWritten < 0)
{
ret = nSectorsWritten;
}
}
}
return ret;
}
/****************************************************************************
* Name: fat_cacheflush
*
* Desciption: Flush any dirty sectors as necessary
*
****************************************************************************/
static int fat_cacheflush(struct fat_mountpt_s *fs)
{
int ret;
/* Check if the fs_buffer is dirty. In this case, we will write back the
* contents of fs_buffer.
*/
if (fs->fs_dirty)
{
/* Write the dirty sector */
ret = fat_hwwrite(fs, fs->fs_buffer, fs->fs_sector, 1);
if (ret < 0)
{
return ret;
}
/* Does the sector lie in the FAT region? */
if (fs->fs_sector < fs->fs_fatbase + fs->fs_fatsize)
{
/* Yes, then make the change in the FAT copy as well */
int i;
for (i = fs->fs_fatnumfats; i >= 2; i--)
{
fs->fs_sector += fs->fs_fatsize;
ret = fat_hwwrite(fs, fs->fs_buffer, fs->fs_sector, 1);
if (ret < 0)
{
return ret;
}
}
}
/* No longer dirty */
fs->fs_dirty = FALSE;
}
return OK;
}
/****************************************************************************
* Name: fat_cacheread
*
* Desciption: Read the specified sector into the sector cache, flushing any
* existing dirty sectors as necessary.
*
****************************************************************************/
static int fat_cacheread(struct fat_mountpt_s *fs, uint32 sector)
{
int ret;
/* fs->sector holds the current sector that is buffered in fs->fs_buffer.
* If the requested sector is the same as this sector, then we do nothing.
* Otherwise, we will have to read the new sector.
*/
if (fs->fs_sector != sector)
{
/* We will need to read the new sector. First, flush the cached
* sector if it is dirty.
*/
ret = fat_cacheflush(fs);
if (ret < 0)
{
return ret;
}
/* Then read the specified sector into the cache */
ret = fat_hwread(fs, fs->fs_buffer, sector, 1);
if (ret < 0)
{
return ret;
}
/* Update the cached sector number */
fs->fs_sector = sector;
}
return OK;
}
/****************************************************************************
* Name: fat_clustger2sector
*
* Desciption: Convert a cluster number to a start sector number
*
****************************************************************************/
static ssize_t fat_cluster2sector(struct fat_mountpt_s *fs, uint32 cluster )
{
cluster -= 2;
if (cluster >= fs->fs_nclusters - 2)
{
return -EINVAL;
}
return cluster * fs->fs_fatsecperclus + fs->fs_database;
}
/****************************************************************************
* Name: fat_getcluster
*
* Desciption: Get the cluster start sector into the FAT
*
****************************************************************************/
static ssize_t fat_getcluster(struct fat_mountpt_s *fs, unsigned int clusterno)
{
/* Verify that the cluster number is within range */
if (clusterno >= 2 && clusterno < fs->fs_nclusters)
{
/* Okay.. Read the next cluster from the FAT. The way we will do
* this depends on the type of FAT filesystm we are dealing with.
*/
switch (fs->fs_type)
{
case FSTYPE_FAT12 :
{
size_t fatsector;
unsigned int fatoffset;
unsigned int startsector;
unsigned int fatindex;
/* FAT12 is more complex because it has 12-bits (1.5 bytes)
* per FAT entry. Get the offset to the first byte:
*/
fatoffset = (clusterno * 3) / 2;
fatsector = fs->fs_fatbase + SEC_NSECTORS(fs, fatoffset);
/* Read the sector at this offset */
if (fat_cacheread(fs, fatsector) < 0)
{
/* Read error */
break;
}
/* Get the first, LS byte of the cluster from the FAT */
fatindex = fatoffset & SEC_NDXMASK(fs);
startsector = fs->fs_buffer[fatindex];
/* With FAT12, the second byte of the cluster number may lie in
* a different sector than the first byte.
*/
fatindex++;
if (fatindex >= fs->fs_hwsectorsize)
{
fatsector++;
fatindex = 0;
if (fat_cacheread(fs, fatsector) < 0)
{
/* Read error */
break;
}
}
/* Get the second, MS byte of the cluster for 16-bits. The
* does not depend on the endian-ness of the target, but only
* on the fact that the byte stream is little-endian.
*/
startsector |= (unsigned int)fs->fs_buffer[fatindex] << 8;
/* Now, pick out the correct 12 bit cluster start sector value */
if ((clusterno & 1) != 0)
{
/* Odd.. take the MS 12-bits */
startsector >>= 4;
}
else
{
/* Even.. take the LS 12-bits */
startsector &= 0x0fff;
}
return startsector;
}
case FSTYPE_FAT16 :
{
unsigned int fatoffset = 2 * clusterno;
size_t fatsector = fs->fs_fatbase + SEC_NSECTORS(fs, fatoffset);
unsigned int fatindex = fatoffset & SEC_NDXMASK(fs);
if (fat_cacheread(fs, fatsector) < 0)
{
/* Read error */
break;
}
return FAT_GETFAT16(fs->fs_buffer, fatindex);
}
case FSTYPE_FAT32 :
{
unsigned int fatoffset = 4 * clusterno;
size_t fatsector = fs->fs_fatbase + SEC_NSECTORS(fs, fatoffset);
unsigned int fatindex = fatoffset & SEC_NDXMASK(fs);
if (fat_cacheread(fs, fatsector) < 0)
{
/* Read error */
break;
}
return FAT_GETFAT16(fs->fs_buffer, fatindex) & 0x0fffffff;
}
default:
break;
}
}
/* There is no cluster information, or an error occured */
return (ssize_t)ERROR;
}
/****************************************************************************
* Name: fat_putcluster
*
* Desciption: Write a new cluster start sector into the FAT
*
****************************************************************************/
static int fat_putcluster(struct fat_mountpt_s *fs, unsigned int clusterno, size_t startsector)
{
/* Verify that the cluster number is within range. Zero erases the cluster. */
if (clusterno == 0 || (clusterno >= 2 && clusterno < fs->fs_nclusters))
{
/* Okay.. Write the next cluster into the FAT. The way we will do
* this depends on the type of FAT filesystm we are dealing with.
*/
switch (fs->fs_type)
{
case FSTYPE_FAT12 :
{
size_t fatsector;
unsigned int fatoffset;
unsigned int fatindex;
ubyte value;
/* FAT12 is more complex because it has 12-bits (1.5 bytes)
* per FAT entry. Get the offset to the first byte:
*/
fatoffset = (clusterno * 3) / 2;
fatsector = fs->fs_fatbase + SEC_NSECTORS(fs, fatoffset);
/* Make sure that the sector at this offset is in the cache */
if (fat_cacheread(fs, fatsector)< 0)
{
/* Read error */
break;
}
/* Output the LS byte first handling the 12-bit alignment within
* the 16-bits
*/
fatindex = fatoffset & SEC_NDXMASK(fs);
if ((clusterno & 1) != 0)
{
value = (fs->fs_buffer[fatindex] & 0x0f) | startsector << 4;
}
else
{
value = (ubyte)startsector;
}
fs->fs_buffer[fatindex] = value;
/* With FAT12, the second byte of the cluster number may lie in
* a different sector than the first byte.
*/
fatindex++;
if (fatindex >= fs->fs_hwsectorsize)
{
/* Read the next sector */
fatsector++;
fatindex = 0;
/* Set the dirty flag to make sure the sector that we
* just modified is written out.
*/
fs->fs_dirty = TRUE;
if (fat_cacheread(fs, fatsector) < 0)
{
/* Read error */
break;
}
}
/* Output the MS byte first handling the 12-bit alignment within
* the 16-bits
*/
if ((clusterno & 1) != 0)
{
value = (ubyte)(startsector >> 4);
}
else
{
value = (fs->fs_buffer[fatindex] & 0xf0) | (startsector & 0x0f);
}
fs->fs_buffer[fatindex] = value;
}
break;
case FSTYPE_FAT16 :
{
unsigned int fatoffset = 2 * clusterno;
size_t fatsector = fs->fs_fatbase + SEC_NSECTORS(fs, fatoffset);
unsigned int fatindex = fatoffset & SEC_NDXMASK(fs);
if (fat_cacheread(fs, fatsector) < 0)
{
/* Read error */
break;
}
FAT_PUTFAT16(fs->fs_buffer, fatindex, startsector & 0xffff);
}
break;
case FSTYPE_FAT32 :
{
unsigned int fatoffset = 4 * clusterno;
size_t fatsector = fs->fs_fatbase + SEC_NSECTORS(fs, fatoffset);
unsigned int fatindex = fatoffset & SEC_NDXMASK(fs);
if (fat_cacheread(fs, fatsector) < 0)
{
/* Read error */
break;
}
FAT_PUTFAT32(fs->fs_buffer, fatindex, startsector & 0x0fffffff);
}
break;
default:
return ERROR;
}
/* Mark the modified sector as "dirty" and return success */
fs->fs_dirty = 1;
return OK;
}
return ERROR;
}
/****************************************************************************
* Name: fat_path2dirname
*
* Desciption: Convert a user filename into a properly formatted FAT
* (short) filname as it would appear in a directory entry. Here are the
* rules for the 11 byte name in the directory:
*
* The first byte:
* - 0xe5 = The directory is free
* - 0x00 = This directory and all following directories are free
* - 0x05 = Really 0xe5
* - 0x20 = May NOT be ' '
*
* Any bytes
* 0x00-0x1f = (except for 0x00 and 0x05 in the first byte)
* 0x22 = '"'
* 0x2a-0x2c = '*', '+', ','
* 0x2e-0x2f = '.', '/'
* 0x3a-0x3f = ':', ';', '<', '=', '>', '?'
* 0x5b-0x5d = '[', '\\', ;]'
* 0x7c = '|'
*
* Upper case characters are not allowed in directory names (without some
* poorly documented operatgions on the NTRes directory byte). Lower case
* codes may represent different characters in other character sets ("DOS
* code pages". The logic below does not, at present, support any other
* character sets.
*
****************************************************************************/
static inline int fat_path2dirname(const char **path, struct fat_dirinfo_s *dirinfo,
char *terminator)
{
#ifdef CONFIG_FAT_LCNAMES
unsigned int ntlcenable = FATNTRES_LCNAME | FATNTRES_LCEXT;
unsigned int ntlcfound = 0;
#endif
const char *node = *path;
int endndx;
ubyte ch;
int ndx = 0;
/* Initialized the name with all spaces */
memset(dirinfo->fd_name, ' ', 8+3);
/* Loop until the name is successfully parsed or an error occurs */
endndx = 8;
for (;;)
{
/* Get the next byte from the path */
ch = *node++;
/* Check if this the last byte in this node of the name */
if ((ch == '\0' || ch == '/') && ndx != 0 )
{
/* Return the accumulated NT flags and the terminating character */
#ifdef CONFIG_FAT_LCNAMES
dirinfo->fd_ntflags = ntlcfound & ntlcenable;
#endif
*terminator = ch;
*path = node;
return OK;
}
/* Accept only the printable character set. Note the first byte
* of the name could be 0x05 meaning that is it 0xe5, but this is
* not a printable character in this character in either case.
*/
else if (!isgraph(ch))
{
goto errout;
}
/* Check for transition from name to extension */
else if (ch == '.')
{
/* Starting the extension */
ndx = 8;
endndx = 11;
continue;
}
/* Reject printable characters forbidden by FAT */
else if (ch == '"' || (ch >= '*' && ch <= ',') ||
ch == '.' || ch == '/' ||
(ch >= ':' && ch <= '?') ||
(ch >= '[' && ch <= ']') ||
(ch == '|'))
{
goto errout;
}
/* Check for upper case charaters */
#ifdef CONFIG_FAT_LCNAMES
else if (isupper(ch))
{
/* Some or all of the characters in the name or extension
* are upper case. Force all of the characters to be interpreted
* as upper case.
*/
if ( endndx == 8)
{
/* Clear lower case name bit in mask*/
ntlcenable &= FATNTRES_LCNAME;
}
else
{
/* Clear lower case extension in mask */
ntlcenable &= FATNTRES_LCNAME;
}
}
#endif
/* Check for lower case characters */
else if (islower(ch))
{
/* Convert the character to upper case */
ch = toupper(ch);
/* Some or all of the characters in the name or extension
* are lower case. They can be interpreted as lower case if
* only if all of the characters in the name or extension are
* lower case.
*/
#ifdef CONFIG_FAT_LCNAMES
if ( endndx == 8)
{
/* Set lower case name bit */
ntlcfound |= FATNTRES_LCNAME;
}
else
{
/* Set lower case extension bit */
ntlcfound |= FATNTRES_LCNAME;
}
#endif
}
/* Check if the file name exceeds the size permitted (without
* long file name support
*/
if (ndx >= endndx)
{
goto errout;
}
/* Save next character in the accumulated name */
dirinfo->fd_name[ndx++] = ch;
}
errout:
return -EINVAL;
}
/****************************************************************************
* Name: fat_dirname2path
*
* Desciption: Convert a filename in a raw directory entry into a user
* filename. This is essentially the inverse operation of that performed
* by fat_path2dirname. See that function for more details.
*
****************************************************************************/
static inline int fat_dirname2path(char *path, struct fat_dirinfo_s *dirinfo)
{
const unsigned char *direntry = dirinfo->fd_entry;
int ch;
int ndx;
/* Check if we will be doing upper to lower case conversions */
#ifdef CONFIG_FAT_LCNAMES
dirinfo->fd_ntflags = DIR_GETNTRES(direntry);
#endif
/* Get the 8-byte filename */
for (ndx = 0; ndx < 8; ndx++)
{
/* Get the next filename character from the directory entry */
ch = direntry[ndx];
/* Any space (or ndx==8) terminates the filename */
if (ch == ' ')
{
break;
}
/* In this version, we never write 0xe5 in the directoryfilenames
* (because we do not handle any character sets where 0xe5 is valid
* in a filaname), but we could encounted this in a filesystem
* written by some other system
*/
if (ndx == 0 && ch == DIR0_E5)
{
ch = 0xe5;
}
/* Check if we should perform upper to lower case conversion
* of the (whole) filename.
*/
#ifdef CONFIG_FAT_LCNAMES
if (dirinfo->fd_ntflags & FATNTRES_LCNAME && isupper(ch))
{
ch = tolower(ch);
}
#endif
/* Copy the next character into the filename */
*path++ = ch;
}
/* Check if there is an extension */
if (direntry[8] != ' ')
{
/* Yes, output the dot before the extension */
*path++ = '.';
/* Then output the (up to) 3 character extension */
for (ndx = 8; ndx < 11; ndx++)
{
/* Get the next extensions character from the directory entry */
ch = dirinfo->fd_name[ndx];
/* Any space (or ndx==11) terminates the extension */
if (ch == ' ')
{
break;
}
/* Check if we should perform upper to lower case conversion
* of the (whole) filename.
*/
#ifdef CONFIG_FAT_LCNAMES
if (ntflags & FATNTRES_LCEXT && isupper(ch))
{
ch = tolower(ch);
}
#endif
/* Copy the next character into the filename */
*path++ = ch;
}
}
/* Put a null terminator at the end of the filename */
*path = '\0';
return OK;
}
/****************************************************************************
* Name: fat_checkfsinfo
*
* Desciption: Read the FAT32 FSINFO sector
*
****************************************************************************/
static int fat_checkfsinfo(struct fat_mountpt_s *fs)
{
/* Verify that this is, indeed, an FSINFO sector */
if (FSI_GETLEADSIG(fs->fs_buffer) == 0x41615252 &&
FSI_GETSTRUCTSIG(fs->fs_buffer) == 0x61417272 &&
FSI_GETTRAILSIG(fs->fs_buffer) == 0xaa550000)
{
fs->fs_fsinextfree = FSI_GETFREECOUNT(fs->fs_buffer);
fs->fs_fsifreecount = FSI_GETNXTFREE(fs->fs_buffer);
return OK;
}
return -ENODEV;
}
/****************************************************************************
* Name: fat_checkbootrecord
*
* Desciption: Read a sector and verify that it is a a FAT boot record.
*
****************************************************************************/
static int fat_checkbootrecord(struct fat_mountpt_s *fs)
{
uint32 ndatasectors;
uint32 fatsize;
uint16 rootdirsectors = 0;
boolean notfat32 = FALSE;
/* Verify the MBR signature at offset 510 in the sector (true even
* if the sector size is greater than 512. All FAT file systems have
* this signature. On a FAT32 volume, the RootEntCount , FatSz16, and
* FatSz32 values should always be zero. The FAT sector size should
* match the reported hardware sector size.
*/
if (MBR_GETSIGNATURE(fs->fs_buffer) != 0xaa55 ||
MBR_GETBYTESPERSEC(fs->fs_buffer) != fs->fs_hwsectorsize)
{
return -ENODEV;
}
/* Verify the FAT32 file system type. The determination of the file
* system type is based on the number of clusters on the volume: FAT12
* volume has < 4085 cluseter, a FAT16 volume has fewer than 65,525
* clusters, and any larger is FAT32.
*
* Get the number of 32-bit directory entries in root directory (zero
* for FAT32.
*/
fs->fs_rootentcnt = MBR_GETROOTENTCNT(fs->fs_buffer);
if (fs->fs_rootentcnt != 0)
{
notfat32 = TRUE; /* Must be zero for FAT32 */
rootdirsectors = (32 * fs->fs_rootentcnt + fs->fs_hwsectorsize - 1) / fs->fs_hwsectorsize;
}
/* Determine the number of sectors in a FAT. */
fs->fs_fatsize = MBR_GETFATSZ16(fs->fs_buffer); /* Should be zero */
if (fs->fs_fatsize)
{
notfat32 = TRUE; /* Must be zero for FAT32 */
}
else
{
fs->fs_fatsize = MBR_GETFATSZ32(fs->fs_buffer);
}
if (!fs->fs_fatsize || fs->fs_fatsize >= fs->fs_hwnsectors)
{
return -ENODEV;
}
/* Get the total number of sectors on the volume. */
fs->fs_fattotsec = MBR_GETTOTSEC16(fs->fs_buffer); /* Should be zero */
if (fs->fs_fattotsec)
{
notfat32 = TRUE; /* Must be zero for FAT32 */
}
else
{
fs->fs_fattotsec = MBR_GETTOTSEC32(fs->fs_buffer);
}
if (!fs->fs_fattotsec || fs->fs_fattotsec > fs->fs_hwnsectors)
{
return -ENODEV;
}
/* Get the total number of reserved sectors */
fs->fs_fatresvdseccount = MBR_GETRESVDSECCOUNT(fs->fs_buffer);
if (fs->fs_fatresvdseccount > fs->fs_hwnsectors)
{
return -ENODEV;
}
/* Get the number of FATs. This is probably two but could have other values */
fs->fs_fatnumfats = MBR_GETNUMFATS(fs->fs_buffer);
fatsize = fs->fs_fatnumfats * fs->fs_fatsize;
/* Get the total number of data sectors */
ndatasectors = fs->fs_fattotsec - fs->fs_fatresvdseccount - fatsize - rootdirsectors;
if (ndatasectors > fs->fs_hwnsectors)
{
return -ENODEV;
}
/* Get the sectors per cluster */
fs->fs_fatsecperclus = MBR_GETSECPERCLUS(fs->fs_buffer);
/* Calculate the number of clusters */
fs->fs_nclusters = ndatasectors / fs->fs_fatsecperclus;
/* Finally, the test: */
if (fs->fs_nclusters < 4085)
{
fs->fs_fsinfo = 0;
fs->fs_type = FSTYPE_FAT12;
}
else if (fs->fs_nclusters < 65525)
{
fs->fs_fsinfo = 0;
fs->fs_type = FSTYPE_FAT16;
}
else if (!notfat32)
{
fs->fs_fsinfo = fs->fs_fatbase + MBR_GETFSINFO(fs->fs_buffer);
fs->fs_type = FSTYPE_FAT32;
}
else
{
return -ENODEV;
}
/* We have what appears to be a valid FAT filesystem! Save a few more things
* from the boot record that we will need later.
*/
fs->fs_fatbase += fs->fs_fatresvdseccount;
if (fs->fs_type == FSTYPE_FAT32)
{
fs->fs_rootbase = MBR_GETROOTCLUS(fs->fs_buffer);
}
else
{
fs->fs_rootbase = fs->fs_fatbase + fatsize;
}
fs->fs_database = fs->fs_fatbase + fatsize + fs->fs_rootentcnt / DIRSEC_NDIRS(fs);
fs->fs_fsifreecount = 0xffffffff;
return OK;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: fat_getuint16
****************************************************************************/
uint16 fat_getuint16(ubyte *ptr)
{
#ifdef CONFIG_ARCH_BIGENDIAN
/* The bytes always have to be swapped if the target is big-endian */
return ((uint16)ptr[0] << 8) | ptr[1];
#else
/* Byte-by-byte transfer is still necessary if the address is un-aligned */
return ((uint16)ptr[1] << 8) | ptr[0];
#endif
}
/****************************************************************************
* Name: fat_getuint32
****************************************************************************/
uint32 fat_getuint32(ubyte *ptr)
{
#ifdef CONFIG_ARCH_BIGENDIAN
/* The bytes always have to be swapped if the target is big-endian */
return ((uint32)fat_getuint16(&ptr[0]) << 16) | fat_getuint16(&ptr[2]);
#else
/* Byte-by-byte transfer is still necessary if the address is un-aligned */
return ((uint32)fat_getuint16(&ptr[2]) << 16) | fat_getuint16(&ptr[0]);
#endif
}
/****************************************************************************
* Name: fat_putuint16
****************************************************************************/
void fat_putuint16(ubyte *ptr, uint16 value16)
{
ubyte *val = (ubyte*)&value16;
#ifdef CONFIG_ARCH_BIGENDIAN
/* The bytes always have to be swapped if the target is big-endian */
ptr[0] = val[1];
ptr[1] = val[0];
#else
/* Byte-by-byte transfer is still necessary if the address is un-aligned */
ptr[0] = val[0];
ptr[1] = val[1];
#endif
}
/****************************************************************************
* Name: fat_putuint32
****************************************************************************/
void fat_putuint32(ubyte *ptr, uint32 value32)
{
uint16 *val = (uint16*)&value32;
#ifdef CONFIG_ARCH_BIGENDIAN
/* The bytes always have to be swapped if the target is big-endian */
fat_putuint16(&ptr[0], val[2]);
fat_putuint16(&ptr[2], val[0]);
#else
/* Byte-by-byte transfer is still necessary if the address is un-aligned */
fat_putuint16(&ptr[0], val[0]);
fat_putuint16(&ptr[2], val[2]);
#endif
}
/****************************************************************************
* Name: fat_semtake
****************************************************************************/
void fat_semtake(struct fat_mountpt_s *fs)
{
/* Take the semaphore (perhaps waiting) */
while (sem_wait(&fs->fs_sem) != 0)
{
/* The only case that an error should occur here is if
* the wait was awakened by a signal.
*/
ASSERT(*get_errno_ptr() == EINTR);
}
}
/****************************************************************************
* Name: fat_semgive
****************************************************************************/
void fat_semgive(struct fat_mountpt_s *fs)
{
sem_post(&fs->fs_sem);
}
/****************************************************************************
* Name: fat_mount
*
* Desciption: This function is called only when the mountpoint is first
* established. It initializes the mountpoint structure and verifies
* that a valid FAT32 filesystem is provided by the block driver.
*
* The caller should hold the mountpoint semaphore
*
****************************************************************************/
int fat_mount(struct fat_mountpt_s *fs, boolean writeable)
{
FAR struct inode *inode;
struct geometry geo;
int ret;
/* Assume that the mount is successful */
fs->fs_mounted = TRUE;
/* Check if there is media available */
inode = fs->fs_blkdriver;
if (!inode || !inode->u.i_bops || !inode->u.i_bops->geometry ||
inode->u.i_bops->geometry(inode, &geo) != OK || !geo.geo_available)
{
ret = -ENODEV;
goto errout;
}
/* Make sure that that the media is write-able (if write access is needed) */
if (writeable && !geo.geo_writeenabled)
{
ret = -EACCES;
goto errout;
}
/* Save the hardware geometry */
fs->fs_hwsectorsize = geo.geo_sectorsize;
fs->fs_hwnsectors = geo.geo_nsectors;
/* Allocate a buffer to hold one hardware sector */
fs->fs_buffer = (ubyte*)malloc(fs->fs_hwsectorsize);
if (!fs->fs_buffer)
{
ret = -ENOMEM;
goto errout;
}
/* Search FAT boot record on the drive. First check at sector zero. This
* could be either the boot record or a partition that refers to the boot
* record.
*
* First read sector zero. This will be the first access to the drive and a
* likely failure point.
*/
fs->fs_fatbase = 0;
ret = fat_hwread(fs, fs->fs_buffer, 0, 1);
if (ret < 0)
{
goto errout_with_buffer;
}
if (fat_checkbootrecord(fs) != OK)
{
/* The contents of sector 0 is not a boot record. It could be a
* partition, however. Assume it is a partition and get the offset
* into the partition table. This table is at offset MBR_TABLE and is
* indexed by 16x the partition number. Here we support only
* parition 0.
*/
ubyte *partition = &fs->fs_buffer[MBR_TABLE + 0];
/* Check if the partition exists and, if so, get the bootsector for that
* partition and see if we can find the boot record there.
*/
if (partition[4])
{
/* There appears to be a partition, get the sector number of the
* partition (LBA)
*/
fs->fs_fatbase = MBR_GETPARTSECTOR(&partition[8]);
/* Read the new candidate boot sector */
ret = fat_hwread(fs, fs->fs_buffer, fs->fs_fatbase, 1);
if (ret < 0)
{
goto errout_with_buffer;
}
/* Check if this is a boot record */
if (fat_checkbootrecord(fs) != OK)
{
goto errout_with_buffer;
}
}
}
/* We have what appears to be a valid FAT filesystem! Now read the
* FSINFO sector (FAT32 only)
*/
if (fs->fs_type == FSTYPE_FAT32)
{
ret = fat_checkfsinfo(fs);
if (ret != OK)
{
goto errout_with_buffer;
}
}
/* We did it! */
dbg("FAT%d:\n", fs->fs_type == 0 ? 12 : fs->fs_type == 1 ? 16 : 32);
dbg("\tHW sector size: %d\n", fs->fs_hwsectorsize);
dbg("\t sectors: %d\n", fs->fs_hwnsectors);
dbg("\tFAT reserved: %d\n", fs->fs_fatresvdseccount);
dbg("\t sectors: %d\n", fs->fs_fattotsec);
dbg("\t start sector: %d\n", fs->fs_fatbase);
dbg("\t root sector: %d\n", fs->fs_rootbase);
dbg("\t root entries: %d\n", fs->fs_rootentcnt);
dbg("\t data sector: %d\n", fs->fs_database);
dbg("\t FSINFO sector: %d\n", fs->fs_fsinfo);
dbg("\t Num FATs: %d\n", fs->fs_fatnumfats);
dbg("\t FAT size: %d\n", fs->fs_fatsize);
dbg("\t sectors/cluster: %d\n", fs->fs_fatsecperclus);
dbg("\t max clusters: %d\n", fs->fs_nclusters);
dbg("\tFSI free count %d\n", fs->fs_fsifreecount);
dbg("\t next free %d\n", fs->fs_fsinextfree);
return OK;
errout_with_buffer:
free(fs->fs_buffer);
fs->fs_buffer = 0;
errout:
fs->fs_mounted = FALSE;
return ret;
}
/****************************************************************************
* Name: fat_checkmount
*
* Desciption: Check if the mountpoint is still valid.
*
* The caller should hold the mountpoint semaphore
*
****************************************************************************/
int fat_checkmount(struct fat_mountpt_s *fs)
{
/* If the fs_mounted flag is FALSE, then we have already handled the loss
* of the mount.
*/
if (fs && fs->fs_mounted)
{
struct fat_file_s *file;
/* We still think the mount is healthy. Check an see if this is
* still the case
*/
if (fs->fs_blkdriver)
{
struct inode *inode = fs->fs_blkdriver;
if (inode && inode->u.i_bops && inode->u.i_bops->geometry)
{
struct geometry geo;
int errcode = inode->u.i_bops->geometry(inode, &geo);
if (errcode == OK && geo.geo_available && !geo.geo_mediachanged)
{
return OK;
}
}
}
/* If we get here, the mount is NOT healthy */
fs->fs_mounted = FALSE;
/* Make sure that this is flagged in every opened file */
for (file = fs->fs_head; file; file = file->ff_next)
{
file->ff_open = FALSE;
}
}
return -ENODEV;
}
/****************************************************************************
* Name: fat_nextdirentry
*
* Desciption: Read the next directory entry from the sector in cache,
* reading the next sector(s) in the cluster as necessary.
*
****************************************************************************/
int fat_nextdirentry(struct fat_dirinfo_s *dirinfo)
{
struct fat_mountpt_s *fs = dirinfo->fs;
unsigned int cluster;
unsigned int ndx;
/* Increment the index to the next 32-byte directory entry */
ndx = dirinfo->fd_index + 1;
/* Check if all of the directory entries in this sectory have
* been examined.
*/
if (ndx >= DIRSEC_NDIRS(fs))
{
/* Yes, then we will have to read the next sector */
dirinfo->fd_currsector++;
/* For FAT12/16, the root directory is a group of sectors relative
* to the first sector of the fat volume.
*/
if (!dirinfo->fd_currcluster)
{
/* For FAT12/13, the boot record tells us number of 32-bit directories
* that are contained in the root directory. This should correspond to
* an even number of sectors.
*/
if (ndx >= fs->fs_rootentcnt)
{
/* When we index past this count, we have examined all of the entries in
* the root directory.
*/
return ERROR;
}
}
else
{
/* Not a FAT12/16 root directory, check if we have examined the entire
* cluster comprising the directory.
*
* The current sector within the cluster is the entry number divided
* byte the number of entries per sector
*/
int sector = ndx / DIRSEC_NDIRS(fs);
/* We are finished with the cluster when the last sector of the cluster
* has been examined.
*/
if (sector >= fs->fs_fatsecperclus)
{
/* Get next cluster */
cluster = fat_getcluster(fs, dirinfo->fd_currcluster);
/* Check if a valid cluster was obtained. */
if (cluster < 2 || cluster >= fs->fs_nclusters)
{
/* No, we have probably reached the end of the cluster list */
return ERROR;
}
/* Initialize for new cluster */
dirinfo->fd_currcluster = cluster;
dirinfo->fd_currsector = fat_cluster2sector(fs, cluster);
}
}
}
/* Save the new index into dirinfo->fd_currsector */
dirinfo->fd_index = ndx;
return OK;
}
/****************************************************************************
* Name: fat_finddirentry
*
* Desciption: Given a path to something that may or may not be in the file
* system, return the directory entry of the item.
*
****************************************************************************/
int fat_finddirentry(struct fat_dirinfo_s *dirinfo, const char *path)
{
struct fat_mountpt_s *fs = dirinfo->fs;
size_t cluster;
ubyte *direntry = NULL;
char terminator;
int ret;
/* Initialize to traverse the chain. Set it to the cluster of
* the root directory
*/
cluster = fs->fs_rootbase;
if (fs->fs_type == FSTYPE_FAT32)
{
/* For FAT32, the root directory is variable sized and is a
* cluster chain like any other directory. fs_rootbase holds
* the first cluster of the root directory.
*/
dirinfo->fd_startcluster = cluster;
dirinfo->fd_currcluster = cluster;
dirinfo->fd_currsector = fat_cluster2sector(fs, cluster);
}
else
{
/* For FAT12/16, the first sector of the root directory is a sector
* relative to the first sector of the fat volume.
*/
dirinfo->fd_startcluster = 0;
dirinfo->fd_currcluster = 0;
dirinfo->fd_currsector = cluster;
}
/* fd_index is the index into the current directory table */
dirinfo->fd_index = 0;
/* If no path was provided, then the root directory must be exactly
* what the caller is looking for.
*/
if (*path == '\0')
{
dirinfo->fd_entry = NULL;
return OK;
}
/* Otherwise, loop until the path is found */
for (;;)
{
/* Convert the next the path segment name into the kind of
* name that we would see in the directory entry.
*/
ret = fat_path2dirname(&path, dirinfo, &terminator);
if (ret < 0)
{
/* ERROR: The filename contains invalid characters or is
* too long.
*/
return ret;
}
/* Now search the current directory entry for an entry with this
* matching name.
*/
for (;;)
{
/* Read the next sector into memory */
ret = fat_cacheread(fs, dirinfo->fd_currsector);
if (ret < 0)
{
return ret;
}
/* Get a pointer to the directory entry */
direntry = &fs->fs_buffer[DIRSEC_BYTENDX(fs, dirinfo->fd_index)];
/* Check if we are at the end of the directory */
if (direntry[DIR_NAME] == DIR0_ALLEMPTY)
{
return -ENOENT;
}
/* Check if we have found the directory entry that we are looking for */
if (direntry[DIR_NAME] != DIR0_EMPTY &&
!(DIR_GETATTRIBUTES(direntry) & FATATTR_VOLUMEID) &&
!memcmp(&direntry[DIR_NAME], dirinfo->fd_name, 8+3) )
{
/* Yes.. break out of the loop */
break;
}
/* No... get the next directory index and try again */
if (fat_nextdirentry(dirinfo) != OK)
{
return -ENOENT;
}
}
/* We get here only if we have found a directory entry that matches
* the path element that we are looking for.
*
* If the terminator character in the path was the end of the string
* then we have successfully found the directory entry that describes
* the path.
*/
if (!terminator)
{
/* Return the pointer to the matching directory entry */
dirinfo->fd_entry = direntry;
return OK;
}
/* No.. then we have found one of the intermediate directories on
* the way to the final path target. In this case, make sure
* the thing that we found is, indeed, a directory.
*/
if (!(DIR_GETATTRIBUTES(direntry) & FATATTR_DIRECTORY))
{
/* Ooops.. we found something else */
return -ENOTDIR;
}
/* Get the cluster number of this directory */
cluster =
((uint32)DIR_GETFSTCLUSTHI(direntry) << 16) |
DIR_GETFSTCLUSTLO(direntry);
/* The restart scanning at the new directory */
dirinfo->fd_currcluster = dirinfo->fd_startcluster = cluster;
dirinfo->fd_currsector = fat_cluster2sector(fs, cluster);
dirinfo->fd_index = 2;
}
}
/****************************************************************************
* Name: fat_dirtruncate
*
* Desciption: Truncate an existing file to zero length
*
****************************************************************************/
int fat_dirtruncate(struct fat_mountpt_s *fs, struct fat_dirinfo_s *dirinfo)
{
#warning "File truncation logic not implemented"
return -ENOSYS;
}
/****************************************************************************
* Name: fat_dircreate
*
* Desciption: Create a directory entry for a new file
*
****************************************************************************/
int fat_dircreate(struct fat_mountpt_s *fs, struct fat_dirinfo_s *dirinfo)
{
#warning "File truncation logic not implemented"
return -ENOSYS;
}
#endif /* CONFIG_FS_FAT */
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