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nuttx/fs/fat/fs_fat32util.c
patacongo 75604f27d0 Fix FAT32 bug 
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@1829 42af7a65-404d-4744-a932-0658087f49c3
2009-05-27 21:44:20 +00:00

2520 lines
68 KiB
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/****************************************************************************
* fs_fat32util.c
*
* Copyright (C) 2007, 2008, 2009 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* References:
* Microsoft FAT documentation
* Some good ideas were leveraged from the FAT implementation:
* 'Copyright (C) 2007, ChaN, all right reserved.'
* which has an unrestricted license.
*
* 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 NuttX 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 <nuttx/fat.h>
#include "fs_internal.h"
#include "fs_fat32.h"
/****************************************************************************
* Definitions
****************************************************************************/
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/****************************************************************************
* Private Variables
****************************************************************************/
/****************************************************************************
* Public Variables
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* 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_checkfsinfo
*
* Desciption: Read the FAT32 FSINFO sector
*
****************************************************************************/
static int fat_checkfsinfo(struct fat_mountpt_s *fs)
{
/* Make sure that the fsinfo sector is in the cache */
if (fat_fscacheread(fs, fs->fs_fsinfo) == OK)
{
/* 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) == BOOT_SIGNATURE32)
{
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 ntotalfatsects;
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) != BOOT_SIGNATURE16 ||
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 <= FAT_MAXCLUST12 (4084) clusters, a FAT16 volume has <=
* FAT_MINCLUST16 (microsfoft says < 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_nfatsects = MBR_GETFATSZ16(fs->fs_buffer); /* Should be zero */
if (fs->fs_nfatsects)
{
notfat32 = TRUE; /* Must be zero for FAT32 */
}
else
{
fs->fs_nfatsects = MBR_GETFATSZ32(fs->fs_buffer);
}
if (!fs->fs_nfatsects || fs->fs_nfatsects >= 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);
ntotalfatsects = fs->fs_fatnumfats * fs->fs_nfatsects;
/* Get the total number of data sectors */
ndatasectors = fs->fs_fattotsec - fs->fs_fatresvdseccount - ntotalfatsects - 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 <= FAT_MAXCLUST12)
{
fs->fs_fsinfo = 0;
fs->fs_type = FSTYPE_FAT12;
}
else if (fs->fs_nclusters <= FAT_MAXCLUST16)
{
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 + ntotalfatsects;
}
fs->fs_database = fs->fs_fatbase + ntotalfatsects + fs->fs_rootentcnt / DIRSEC_NDIRS(fs);
fs->fs_fsifreecount = 0xffffffff;
return OK;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: fat_getuint16
****************************************************************************/
uint16 fat_getuint16(ubyte *ptr)
{
#ifdef CONFIG_ENDIAN_BIG
/* 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_ENDIAN_BIG
/* 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_ENDIAN_BIG
/* 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_ENDIAN_BIG
/* 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_systime2fattime
*
* Desciption: Get the system time convertto a time and and date suitble
* for writing into the FAT FS.
*
* TIME in LS 16-bits:
* Bits 0:4 = 2 second count (0-29 representing 0-58 seconds)
* Bits 5-10 = minutes (0-59)
* Bits 11-15 = hours (0-23)
* DATE in MS 16-bits
* Bits 0:4 = Day of month (0-31)
* Bits 5:8 = Month of year (1-12)
* Bits 9:15 = Year from 1980 (0-127 representing 1980-2107)
*
****************************************************************************/
uint32 fat_systime2fattime(void)
{
#ifdef CONFIG_CPP_HAVE_WARNING
# warning "Time not implemented"
#endif
return 0;
}
/****************************************************************************
* Name: fat_fattime2systime
*
* Desciption: Convert FAT data and time to a system time_t
*
* 16-bit FAT time:
* Bits 0:4 = 2 second count (0-29 representing 0-58 seconds)
* Bits 5-10 = minutes (0-59)
* Bits 11-15 = hours (0-23)
* 16-bit FAT date:
* Bits 0:4 = Day of month (0-31)
* Bits 5:8 = Month of year (1-12)
* Bits 9:15 = Year from 1980 (0-127 representing 1980-2107)
*
****************************************************************************/
time_t fat_fattime2systime(uint16 fattime, uint16 fatdate)
{
#ifdef CONFIG_CPP_HAVE_WARNING
# warning "Time not implemented"
#endif
return 0;
}
/****************************************************************************
* 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
* partition 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 (PART1_GETTYPE(fs->fs_buffer) == 0)
{
fdbg("No MBR or partition\n");
goto errout_with_buffer;
}
/* There appears to be a partition, get the sector number of the
* partition (LBA)
*/
fs->fs_fatbase = PART1_GETSTARTSECTOR(fs->fs_buffer);
/* 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)
{
fdbg("No valid MBR\n");
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! */
fdbg("FAT%d:\n", fs->fs_type == 0 ? 12 : fs->fs_type == 1 ? 16 : 32);
fdbg("\tHW sector size: %d\n", fs->fs_hwsectorsize);
fdbg("\t sectors: %d\n", fs->fs_hwnsectors);
fdbg("\tFAT reserved: %d\n", fs->fs_fatresvdseccount);
fdbg("\t sectors: %d\n", fs->fs_fattotsec);
fdbg("\t start sector: %d\n", fs->fs_fatbase);
fdbg("\t root sector: %d\n", fs->fs_rootbase);
fdbg("\t root entries: %d\n", fs->fs_rootentcnt);
fdbg("\t data sector: %d\n", fs->fs_database);
fdbg("\t FSINFO sector: %d\n", fs->fs_fsinfo);
fdbg("\t Num FATs: %d\n", fs->fs_fatnumfats);
fdbg("\t FAT sectors: %d\n", fs->fs_nfatsects);
fdbg("\t sectors/cluster: %d\n", fs->fs_fatsecperclus);
fdbg("\t max clusters: %d\n", fs->fs_nclusters);
fdbg("\tFSI free count %d\n", fs->fs_fsifreecount);
fdbg("\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_hwread
*
* Desciption: Read the specified sector into the sector buffer
*
****************************************************************************/
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
*
****************************************************************************/
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_cluster2sector
*
* Desciption: Convert a cluster number to a start sector number
*
****************************************************************************/
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 next cluster start from the FAT.
*
* Return: <0: error, 0:cluster unassigned, >=0: start sector of cluster
*
****************************************************************************/
ssize_t fat_getcluster(struct fat_mountpt_s *fs, uint32 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 cluster;
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_fscacheread(fs, fatsector) < 0)
{
/* Read error */
break;
}
/* Get the first, LS byte of the cluster from the FAT */
fatindex = fatoffset & SEC_NDXMASK(fs);
cluster = 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_fscacheread(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.
*/
cluster |= (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 */
cluster >>= 4;
}
else
{
/* Even.. take the LS 12-bits */
cluster &= 0x0fff;
}
return cluster;
}
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_fscacheread(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_fscacheread(fs, fatsector) < 0)
{
/* Read error */
break;
}
return FAT_GETFAT32(fs->fs_buffer, fatindex) & 0x0fffffff;
}
default:
break;
}
}
/* There is no cluster information, or an error occured */
return (ssize_t)-EINVAL;
}
/****************************************************************************
* Name: fat_putcluster
*
* Desciption: Write a new cluster into the FAT
*
****************************************************************************/
int fat_putcluster(struct fat_mountpt_s *fs, uint32 clusterno, size_t nextcluster)
{
/* 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_fscacheread(fs, fatsector)< 0)
{
/* Read error */
break;
}
/* Get the LS byte first handling the 12-bit alignment within
* the 16-bits
*/
fatindex = fatoffset & SEC_NDXMASK(fs);
if ((clusterno & 1) != 0)
{
/* Save the LS four bits of the next cluster */
value = (fs->fs_buffer[fatindex] & 0x0f) | nextcluster << 4;
}
else
{
/* Save the LS eight bits of the next cluster */
value = (ubyte)nextcluster;
}
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_fscacheread(fs, fatsector) < 0)
{
/* Read error */
break;
}
}
/* Output the MS byte first handling the 12-bit alignment within
* the 16-bits
*/
if ((clusterno & 1) != 0)
{
/* Save the MS eight bits of the next cluster */
value = (ubyte)(nextcluster >> 4);
}
else
{
/* Save the MS four bits of the next cluster */
value = (fs->fs_buffer[fatindex] & 0xf0) | ((nextcluster >> 8) & 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_fscacheread(fs, fatsector) < 0)
{
/* Read error */
break;
}
FAT_PUTFAT16(fs->fs_buffer, fatindex, nextcluster & 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_fscacheread(fs, fatsector) < 0)
{
/* Read error */
break;
}
FAT_PUTFAT32(fs->fs_buffer, fatindex, nextcluster & 0x0fffffff);
}
break;
default:
return -EINVAL;
}
/* Mark the modified sector as "dirty" and return success */
fs->fs_dirty = 1;
return OK;
}
return -EINVAL;
}
/****************************************************************************
* Name: fat_removechain
*
* Desciption: Remove an entire chain of clusters, starting with 'cluster'
*
****************************************************************************/
int fat_removechain(struct fat_mountpt_s *fs, uint32 cluster)
{
sint32 nextcluster;
int ret;
/* Loop while there are clusters in the chain */
while (cluster >= 2 && cluster < fs->fs_nclusters)
{
/* Get the next cluster after the current one */
nextcluster = fat_getcluster(fs, cluster);
if (nextcluster < 0)
{
/* Error! */
return nextcluster;
}
/* Then nullify current cluster -- removing it from the chain */
ret = fat_putcluster(fs, cluster, 0);
if (ret < 0)
{
return ret;
}
/* Update FSINFINFO data */
if (fs->fs_fsifreecount != 0xffffffff)
{
fs->fs_fsifreecount++;
fs->fs_fsidirty = 1;
}
/* Then set up to remove the next cluster */
cluster = nextcluster;
}
return OK;
}
/****************************************************************************
* Name: fat_extendchain
*
* Desciption: Add a new cluster to the chain following cluster (if cluster
* is non-NULL). if cluster is zero, then a new chain is created.
*
* Return: <0:error, 0: no free cluster, >=2: new cluster number
*
****************************************************************************/
sint32 fat_extendchain(struct fat_mountpt_s *fs, uint32 cluster)
{
ssize_t startsector;
uint32 newcluster;
uint32 startcluster;
int ret;
/* The special value 0 is used when the new chain should start */
if (cluster == 0)
{
/* The FSINFO NextFree entry should be a good starting point
* in the search for a new cluster
*/
startcluster = fs->fs_fsinextfree;
if (startcluster == 0 || startcluster >= fs->fs_nclusters)
{
/* But it is bad.. we have to start at the beginning */
startcluster = 1;
}
}
else
{
/* We are extending an existing chain. Verify that this
* is a valid cluster by examining its start sector.
*/
startsector = fat_getcluster(fs, cluster);
if (startsector < 0)
{
/* An error occurred, return the error value */
return startsector;
}
else if (startsector < 2)
{
/* Oops.. this cluster does not exist. */
return 0;
}
else if (startsector < fs->fs_nclusters)
{
/* It is already followed by next cluster */
return startsector;
}
/* Okay.. it checks out */
startcluster = cluster;
}
/* Loop until (1) we discover that there are not free clusters
* (return 0), an errors occurs (return -errno), or (3) we find
* the next cluster (return the new cluster number).
*/
newcluster = startcluster;
for (;;)
{
/* Examine the next cluster in the FAT */
newcluster++;
if (newcluster >= fs->fs_nclusters)
{
/* If we hit the end of the available clusters, then
* wrap back to the beginning because we might have
* started at a non-optimal place. But don't continue
* past the start cluster.
*/
newcluster = 2;
if (newcluster > startcluster)
{
/* We are back past the starting cluster, then there
* is no free cluster.
*/
return 0;
}
}
/* We have a candidate cluster. Check if the cluster number is
* mapped to a group of sectors.
*/
startsector = fat_getcluster(fs, newcluster);
if (startsector == 0)
{
/* Found have found a free cluster break out*/
break;
}
else if (startsector < 0)
{
/* Some error occurred, return the error number */
return startsector;
}
/* We wrap all the back to the starting cluster? If so, then
* there are no free clusters.
*/
if (newcluster == startcluster)
{
return 0;
}
}
/* We get here only if we break out with an available cluster
* number in 'newcluster' Now mark that cluster as in-use.
*/
ret = fat_putcluster(fs, newcluster, 0x0fffffff);
if (ret < 0)
{
/* An error occurred */
return ret;
}
/* And link if to the start cluster (if any)*/
if (cluster)
{
/* There is a start cluster -- link it */
ret = fat_putcluster(fs, cluster, newcluster);
if (ret < 0)
{
return ret;
}
}
/* And update the FINSINFO for the next time we have to search */
fs->fs_fsinextfree = newcluster;
if (fs->fs_fsifreecount != 0xffffffff)
{
fs->fs_fsifreecount--;
fs->fs_fsidirty = 1;
}
/* Return then number of the new cluster that was added to the chain */
return newcluster;
}
/****************************************************************************
* 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_mountpt_s *fs, struct fs_fatdir_s *dir)
{
unsigned int cluster;
unsigned int ndx;
/* Increment the index to the next 32-byte directory entry */
ndx = dir->fd_index + 1;
/* Check if all of the directory entries in this sectory have
* been examined.
*/
if ((ndx & (DIRSEC_NDIRS(fs)-1)) == 0)
{
/* Yes, then we will have to read the next sector */
dir->fd_currsector++;
/* For FAT12/16, the root directory is a group of sectors relative
* to the first sector of the fat volume.
*/
if (!dir->fd_currcluster)
{
/* For FAT12/16, 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-1)) == 0)
{
/* Get next cluster */
cluster = fat_getcluster(fs, dir->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 */
dir->fd_currcluster = cluster;
dir->fd_currsector = fat_cluster2sector(fs, cluster);
}
}
}
/* Save the new index into dir->fd_currsector */
dir->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_mountpt_s *fs, struct fat_dirinfo_s *dirinfo,
const char *path)
{
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->dir.fd_startcluster = cluster;
dirinfo->dir.fd_currcluster = cluster;
dirinfo->dir.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->dir.fd_startcluster = 0;
dirinfo->dir.fd_currcluster = 0;
dirinfo->dir.fd_currsector = cluster;
}
/* fd_index is the index into the current directory table */
dirinfo->dir.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_fscacheread(fs, dirinfo->dir.fd_currsector);
if (ret < 0)
{
return ret;
}
/* Get a pointer to the directory entry */
direntry = &fs->fs_buffer[DIRSEC_BYTENDX(fs, dirinfo->dir.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(fs, &dirinfo->dir) != 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->dir.fd_currcluster = dirinfo->dir.fd_startcluster = cluster;
dirinfo->dir.fd_currsector = fat_cluster2sector(fs, cluster);
dirinfo->dir.fd_index = 2;
}
}
/****************************************************************************
* Name: fat_allocatedirentry
*
* Desciption: Find a free directory entry
*
****************************************************************************/
int fat_allocatedirentry(struct fat_mountpt_s *fs, struct fat_dirinfo_s *dirinfo)
{
sint32 cluster;
size_t sector;
ubyte *direntry;
ubyte ch;
int ret;
int i;
/* Re-initialize directory object */
cluster = dirinfo->dir.fd_startcluster;
if (cluster)
{
/* Cluster chain can be extended */
dirinfo->dir.fd_currcluster = cluster;
dirinfo->dir.fd_currsector = fat_cluster2sector(fs, cluster);
}
else
{
/* Fixed size FAT12/16 root directory is at fixxed offset/size */
dirinfo->dir.fd_currsector = fs->fs_rootbase;
}
dirinfo->dir.fd_index = 0;
for (;;)
{
unsigned int dirindex;
/* Read the directory sector into fs_buffer */
ret = fat_fscacheread(fs, dirinfo->dir.fd_currsector);
if (ret < 0)
{
return ret;
}
/* Get a pointer to the entry at fd_index */
dirindex = (dirinfo->dir.fd_index & DIRSEC_NDXMASK(fs)) * 32;
direntry = &fs->fs_buffer[dirindex];
/* Check if this directory entry is empty */
ch = direntry[DIR_NAME];
if (ch == DIR0_ALLEMPTY || ch == DIR0_EMPTY)
{
/* It is empty -- we have found a directory entry */
dirinfo->fd_entry = direntry;
return OK;
}
ret = fat_nextdirentry(fs, &dirinfo->dir);
if (ret < 0)
{
return ret;
}
}
/* If we get here, then we have reached the end of the directory table
* in this sector without finding a free directory enty.
*
* It this is a fixed size dirctory entry, then this is an error.
* Otherwise, we can try to extend the directory cluster chain to
* make space for the new directory entry.
*/
if (!cluster)
{
/* The size is fixed */
return -ENOSPC;
}
/* Try to extend the cluster chain for this directory */
cluster = fat_extendchain(fs, dirinfo->dir.fd_currcluster);
if (cluster < 0)
{
return cluster;
}
/* Flush out any cached date in fs_buffer.. we are going to use
* it to initialize the new directory cluster.
*/
ret = fat_fscacheflush(fs);
if (ret < 0)
{
return ret;
}
/* Clear all sectors comprising the new directory cluster */
fs->fs_currentsector = fat_cluster2sector(fs, cluster);
memset(fs->fs_buffer, 0, fs->fs_hwsectorsize);
sector = sector;
for (i = fs->fs_fatsecperclus; i; i--)
{
ret = fat_hwwrite(fs, fs->fs_buffer, sector, 1);
if ( ret < 0)
{
return ret;
}
sector++;
}
dirinfo->fd_entry = fs->fs_buffer;
return OK;
}
/****************************************************************************
* 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.
*
****************************************************************************/
int fat_dirname2path(char *path, ubyte *direntry)
{
#ifdef CONFIG_FAT_LCNAMES
ubyte ntflags;
#endif
int ch;
int ndx;
/* Check if we will be doing upper to lower case conversions */
#ifdef CONFIG_FAT_LCNAMES
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 (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 = direntry[DIR_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_dirtruncate
*
* Desciption: Truncate an existing file to zero length
*
* Assumptions: The caller holds mountpoint semaphore, fs_buffer holds
* the directory entry, dirinfo refers to the current fs_buffer content.
*
****************************************************************************/
int fat_dirtruncate(struct fat_mountpt_s *fs, struct fat_dirinfo_s *dirinfo)
{
unsigned int startcluster;
uint32 writetime;
size_t savesector;
int ret;
/* Get start cluster of the file to truncate */
startcluster =
((uint32)DIR_GETFSTCLUSTHI(dirinfo->fd_entry) << 16) |
DIR_GETFSTCLUSTLO(dirinfo->fd_entry);
/* Clear the cluster start value in the directory and set the file size
* to zero. This makes the file look empty but also have to dispose of
* all of the clusters in the chain.
*/
DIR_PUTFSTCLUSTHI(dirinfo->fd_entry, 0);
DIR_PUTFSTCLUSTLO(dirinfo->fd_entry, 0);
DIR_PUTFILESIZE(dirinfo->fd_entry, 0);
/* Set the ARCHIVE attribute and update the write time */
DIR_PUTATTRIBUTES(dirinfo->fd_entry, FATATTR_ARCHIVE);
writetime = fat_systime2fattime();
DIR_PUTWRTTIME(dirinfo->fd_entry, writetime & 0xffff);
DIR_PUTWRTDATE(dirinfo->fd_entry, writetime > 16);
/* This sector needs to be written back to disk eventually */
fs->fs_dirty = TRUE;
/* Now remove the entire cluster chain comprising the file */
savesector = fs->fs_currentsector;
ret = fat_removechain(fs, startcluster);
if (ret < 0)
{
return ret;
}
/* Setup FSINFO to resuse this cluster next */
fs->fs_fsinextfree = startcluster - 1;
/* Make sure that the directory is still in the cache */
return fat_fscacheread(fs, savesector);
}
/****************************************************************************
* 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)
{
ubyte *direntry;
uint32 time;
int ret;
/* Set up the directory entry */
ret = fat_allocatedirentry(fs, dirinfo);
if (ret != OK)
{
/* Failed to set up directory entry */
return ret;
}
/* Initialize the 32-byte directory entry */
direntry = dirinfo->fd_entry;
memset(direntry, 0, 32);
/* Directory name info */
memcpy(&direntry[DIR_NAME], dirinfo->fd_name, 8+3);
#ifdef CONFIG_FLAT_LCNAMES
DIR_PUTNTRES(dirinfo->fd_entry, dirinfo->fd_ntflags);
#else
DIR_PUTNTRES(dirinfo->fd_entry, 0);
#endif
/* ARCHIVE attribute, write time, creation time */
DIR_PUTATTRIBUTES(dirinfo->fd_entry, FATATTR_ARCHIVE);
time = fat_systime2fattime();
DIR_PUTWRTTIME(dirinfo->fd_entry, time & 0xffff);
DIR_PUTCRTIME(dirinfo->fd_entry, time & 0xffff);
DIR_PUTWRTDATE(dirinfo->fd_entry, time >> 16);
DIR_PUTCRDATE(dirinfo->fd_entry, time >> 16);
fs->fs_dirty = TRUE;
return OK;
}
/****************************************************************************
* Name: fat_remove
*
* Desciption: Remove a directory or file from the file system. This
* implements both rmdir() and unlink().
*
****************************************************************************/
int fat_remove(struct fat_mountpt_s *fs, const char *relpath, boolean directory)
{
struct fat_dirinfo_s dirinfo;
uint32 dircluster;
size_t dirsector;
int ret;
/* Find the directory entry referring to the entry to be deleted */
ret = fat_finddirentry(fs, &dirinfo, relpath);
if (ret != OK)
{
/* No such path */
return -ENOENT;
}
/* Check if this is a FAT12/16 root directory */
if (dirinfo.fd_entry == NULL)
{
/* The root directory cannot be removed */
return -EPERM;
}
/* The object has to have write access to be deleted */
if ((DIR_GETATTRIBUTES(dirinfo.fd_entry) & FATATTR_READONLY) != 0)
{
/* It is a read-only entry */
return -EACCES;
}
/* Get the directory sector and cluster containing the
* entry to be deleted
*/
dirsector = fs->fs_currentsector;
dircluster =
((uint32)DIR_GETFSTCLUSTHI(dirinfo.fd_entry) << 16) |
DIR_GETFSTCLUSTLO(dirinfo.fd_entry);
/* Is this entry a directory? */
if (DIR_GETATTRIBUTES(dirinfo.fd_entry) & FATATTR_DIRECTORY)
{
/* It is a sub-directory. Check if we are be asked to remove
* a directory or a file.
*/
if (!directory)
{
/* We are asked to delete a file */
return -EISDIR;
}
/* We are asked to delete a directory. Check if this
* sub-directory is empty
*/
dirinfo.dir.fd_currcluster = dircluster;
dirinfo.dir.fd_currsector = fat_cluster2sector(fs, dircluster);
dirinfo.dir.fd_index = 2;
/* Loop until either (1) an entry is found in the directory
* (error), (2) the directory is found to be empty, or (3) some
* error occurs.
*/
for (;;)
{
unsigned int subdirindex;
ubyte *subdirentry;
/* Make sure that the sector containing the of the
* subdirectory sector is in the cache
*/
ret = fat_fscacheread(fs, dirinfo.dir.fd_currsector);
if (ret < 0)
{
return ret;
}
/* Get a reference to the next entry in the directory */
subdirindex = (dirinfo.dir.fd_index & DIRSEC_NDXMASK(fs)) * 32;
subdirentry = &fs->fs_buffer[subdirindex];
/* Is this the last entry in the direcory? */
if (subdirentry[DIR_NAME] == DIR0_ALLEMPTY)
{
/* Yes then the directory is empty. Break out of the
* loop and delete the directory.
*/
break;
}
/* Check if the next entry refers to a file or directory */
if (subdirentry[DIR_NAME] != DIR0_EMPTY &&
!(DIR_GETATTRIBUTES(subdirentry) & FATATTR_VOLUMEID))
{
/* The directory is not empty */
return -ENOTEMPTY;
}
/* Get the next directgory entry */
ret = fat_nextdirentry(fs, &dirinfo.dir);
if (ret < 0)
{
return ret;
}
}
}
else
{
/* It is a file. Check if we are be asked to remove a directory
* or a file.
*/
if (directory)
{
/* We are asked to remove a directory */
return -ENOTDIR;
}
}
/* Make sure that the directory containing the entry to be deleted is
* in the cache.
*/
ret = fat_fscacheread(fs, dirsector);
if (ret < 0)
{
return ret;
}
/* Mark the directory entry 'deleted' */
dirinfo.fd_entry[DIR_NAME] = DIR0_EMPTY;
fs->fs_dirty = TRUE;
/* And remove the cluster chain making up the subdirectory */
ret = fat_removechain(fs, dircluster);
if (ret < 0)
{
return ret;
}
/* Update the FSINFO sector (FAT32) */
ret = fat_updatefsinfo(fs);
if (ret < 0)
{
return ret;
}
return OK;
}
/****************************************************************************
* Name: fat_fscacheflush
*
* Desciption: Flush any dirty sector if fs_buffer as necessary
*
****************************************************************************/
int fat_fscacheflush(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_currentsector, 1);
if (ret < 0)
{
return ret;
}
/* Does the sector lie in the FAT region? */
if (fs->fs_currentsector < fs->fs_fatbase + fs->fs_nfatsects)
{
/* Yes, then make the change in the FAT copy as well */
int i;
for (i = fs->fs_fatnumfats; i >= 2; i--)
{
fs->fs_currentsector += fs->fs_nfatsects;
ret = fat_hwwrite(fs, fs->fs_buffer, fs->fs_currentsector, 1);
if (ret < 0)
{
return ret;
}
}
}
/* No longer dirty */
fs->fs_dirty = FALSE;
}
return OK;
}
/****************************************************************************
* Name: fat_fscacheread
*
* Desciption: Read the specified sector into the sector cache, flushing any
* existing dirty sectors as necessary.
*
****************************************************************************/
int fat_fscacheread(struct fat_mountpt_s *fs, size_t sector)
{
int ret;
/* fs->fs_currentsector 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_currentsector != sector)
{
/* We will need to read the new sector. First, flush the cached
* sector if it is dirty.
*/
ret = fat_fscacheflush(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_currentsector = sector;
}
return OK;
}
/****************************************************************************
* Name: fat_ffcacheflush
*
* Desciption: Flush any dirty sectors as necessary
*
****************************************************************************/
int fat_ffcacheflush(struct fat_mountpt_s *fs, struct fat_file_s *ff)
{
int ret;
/* Check if the ff_buffer is dirty. In this case, we will write back the
* contents of ff_buffer.
*/
if (ff->ff_cachesector &&
ff->ff_bflags && (FFBUFF_DIRTY|FFBUFF_VALID) == (FFBUFF_DIRTY|FFBUFF_VALID))
{
/* Write the dirty sector */
ret = fat_hwwrite(fs, ff->ff_buffer, ff->ff_cachesector, 1);
if (ret < 0)
{
return ret;
}
/* No longer dirty, but still valid */
ff->ff_bflags &= ~FFBUFF_DIRTY;
}
return OK;
}
/****************************************************************************
* Name: fat_ffcacheread
*
* Desciption: Read the specified sector into the sector cache, flushing any
* existing dirty sectors as necessary.
*
****************************************************************************/
int fat_ffcacheread(struct fat_mountpt_s *fs, struct fat_file_s *ff, size_t sector)
{
int ret;
/* ff->ff_cachesector holds the current sector that is buffered in
* ff->ff_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 (ff->ff_cachesector != sector || (ff->ff_bflags & FFBUFF_VALID) == 0)
{
/* We will need to read the new sector. First, flush the cached
* sector if it is dirty.
*/
ret = fat_ffcacheflush(fs, ff);
if (ret < 0)
{
return ret;
}
/* Then read the specified sector into the cache */
ret = fat_hwread(fs, ff->ff_buffer, sector, 1);
if (ret < 0)
{
return ret;
}
/* Update the cached sector number */
ff->ff_cachesector = sector;
ff->ff_bflags |= FFBUFF_VALID;
}
return OK;
}
/****************************************************************************
* Name: fat_ffcacheread
*
* Desciption: Invalidate the current file buffer contents
*
****************************************************************************/
int fat_ffcacheinvalidate(struct fat_mountpt_s *fs, struct fat_file_s *ff)
{
int ret;
/* Is there anything valid in the buffer now? */
if ((ff->ff_bflags & FFBUFF_VALID) != 0)
{
/* We will invalidate the buffered sector */
ret = fat_ffcacheflush(fs, ff);
if (ret < 0)
{
return ret;
}
/* Then discard the current cache contents */
ff->ff_bflags &= ~FFBUFF_VALID;
ff->ff_cachesector = 0;
}
return OK;
}
/****************************************************************************
* Name: fat_updatefsinfo
*
* Desciption: Flush evertyhing buffered for the mountpoint and update
* the FSINFO sector, if appropriate
*
****************************************************************************/
int fat_updatefsinfo(struct fat_mountpt_s *fs)
{
int ret;
/* Flush the fs_buffer if it is dirty */
ret = fat_fscacheflush(fs);
if (ret == OK)
{
/* The FSINFO sector only has to be update for the case of a FAT32 file
* system. Check if the file system type.. If this is a FAT32 file
* system then the fs_fsidirty flag will indicate if the FSINFO sector
* needs to be re-written.
*/
if (fs->fs_type == FSTYPE_FAT32 && fs->fs_fsidirty)
{
/* Create an image of the FSINFO sector in the fs_buffer */
memset(fs->fs_buffer, 0, fs->fs_hwsectorsize);
FSI_PUTLEADSIG(fs->fs_buffer, 0x41615252);
FSI_PUTSTRUCTSIG(fs->fs_buffer, 0x61417272);
FSI_PUTFREECOUNT(fs->fs_buffer, fs->fs_fsifreecount);
FSI_PUTNXTFREE(fs->fs_buffer, fs->fs_fsinextfree);
FSI_PUTTRAILSIG(fs->fs_buffer, BOOT_SIGNATURE32);
/* Then flush this to disk */
fs->fs_currentsector = fs->fs_fsinfo;
fs->fs_dirty = TRUE;
ret = fat_fscacheflush(fs);
/* No longer dirty */
fs->fs_fsidirty = FALSE;
}
}
return ret;
}
/****************************************************************************
* Name: fat_nfreeclusters
*
* Desciption: Get the number of free clusters
*
****************************************************************************/
int fat_nfreeclusters(struct fat_mountpt_s *fs, size_t *pfreeclusters)
{
uint32 nfreeclusters;
/* If number of the first free cluster is valid, then just return that value. */
if (fs->fs_fsifreecount <= fs->fs_nclusters - 2)
{
*pfreeclusters = fs->fs_fsifreecount;
return OK;
}
/* Otherwise, we will have to count the number of free clusters */
nfreeclusters = 0;
if (fs->fs_type == FSTYPE_FAT12)
{
size_t sector;
/* Examine every cluster in the fat */
for (sector = 2; sector < fs->fs_nclusters; sector++)
{
/* If the cluster is unassigned, then increment the count of free clusters */
if ((uint16)fat_getcluster(fs, sector) == 0)
{
nfreeclusters++;
}
}
}
else
{
unsigned int cluster;
size_t fatsector;
unsigned int offset;
int ret;
fatsector = fs->fs_fatbase;
offset = fs->fs_hwsectorsize;
/* Examine each cluster in the fat */
for (cluster = fs->fs_nclusters; cluster > 0; cluster--)
{
/* If we are starting a new sector, then read the new sector in fs_buffer */
if (offset >= fs->fs_hwsectorsize)
{
ret = fat_fscacheread(fs, fatsector++);
if (ret < 0)
{
return ret;
}
/* Reset the offset to the next FAT entry.
* Increment the sector number to read next time around.
*/
offset = 0;
fatsector++;
}
/* FAT16 and FAT32 differ only on the size of each cluster start
* sector number in the FAT.
*/
if (fs->fs_type == FSTYPE_FAT16)
{
if (FAT_GETFAT16(fs->fs_buffer, offset) == 0)
{
nfreeclusters++;
}
offset += 2;
}
else
{
if (FAT_GETFAT32(fs->fs_buffer, offset) == 0)
{
nfreeclusters++;
}
offset += 4;
}
}
}
fs->fs_fsifreecount = nfreeclusters;
if (fs->fs_type == FSTYPE_FAT32)
{
fs->fs_fsidirty = TRUE;
}
*pfreeclusters = nfreeclusters;
return OK;
}
/****************************************************************************
* Name: fat_nfreeclusters
*
* Desciption:
* Given the file position, set the correct current sector to access.
*
****************************************************************************/
int fat_currentsector(struct fat_mountpt_s *fs, struct fat_file_s *ff,
off_t position)
{
int sectoroffset;
if (position <= ff->ff_size )
{
/* sectoroffset is the sector number offset into the current cluster */
sectoroffset = SEC_NSECTORS(fs, position) & CLUS_NDXMASK(fs);
/* The current cluster is the the first sector of the cluster plus
* the sector offset
*/
ff->ff_currentsector = fat_cluster2sector(fs, ff->ff_currentcluster)
+ sectoroffset;
/* The remainder is the number of sectors left in the cluster to be
* read/written
*/
ff->ff_sectorsincluster = fs->fs_fatsecperclus - sectoroffset;
fvdbg("position=%d currentsector=%d sectorsincluster=%d\n",
position, ff->ff_currentsector, ff->ff_sectorsincluster);
return OK;
}
/* The position does not lie within the file */
return -ENOSPC;
}
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