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nuttx/fs/fat/fs_fat32dirent.c
patacongo 09c2e9b9e3 Separate FAT directory operations into a separate file 
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3777 42af7a65-404d-4744-a932-0658087f49c3
2011-07-12 22:38:21 +00:00

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/****************************************************************************
* fs/fat/fs_fat32dirent.c
*
* Copyright (C) 2011 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 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.
*
****************************************************************************/
/****************************************************************************
* NOTE: If CONFIG_FAT_LFN is defined, then there may be some legal, patent
* issues. The following was extracted from the entry "File Allocation Table
* from Wikipedia, the free encyclopedia:
*
* "On December 3, 2003 Microsoft announced it would be offering licenses
* for use of its FAT specification and 'associated intellectual property',
* at the cost of a US$0.25 royalty per unit sold, with a $250,000 maximum
* royalty per license agreement.
*
* o "U.S. Patent 5,745,902 (http://www.google.com/patents?vid=5745902) -
* Method and system for accessing a file using file names having
* different file name formats. ...
* o "U.S. Patent 5,579,517 (http://www.google.com/patents?vid=5579517) -
* Common name space for long and short filenames. ...
* o "U.S. Patent 5,758,352 (http://www.google.com/patents?vid=5758352) -
* Common name space for long and short filenames. ...
* o "U.S. Patent 6,286,013 (http://www.google.com/patents?vid=6286013) -
* Method and system for providing a common name space for long and
* short file names in an operating system. ...
*
* "Many technical commentators have concluded that these patents only cover
* FAT implementations that include support for long filenames, and that
* removable solid state media and consumer devices only using short names
* would be unaffected. ..."
*
* So you have been forewarned: Use the long filename at your own risk!
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.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;
uint8_t 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;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* 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)
{
off_t cluster;
uint8_t *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_t)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)
{
int32_t cluster;
off_t sector;
uint8_t *direntry;
uint8_t 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)) * DIR_SIZE;
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_freedirentry
*
* Desciption: Free the directory entry.
*
* Assumptions: (1) the directory enty is in the cache and (2) direntry
* points to the directory entry to be deleted. This obvioulsy needs
* to be re-designed to support long file names!
*
****************************************************************************/
int fat_freedirentry(struct fat_mountpt_s *fs, FAR uint8_t *direntry)
{
direntry[DIR_NAME] = DIR0_EMPTY;
fs->fs_dirty = true;
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, uint8_t *direntry)
{
#ifdef CONFIG_FAT_LCNAMES
uint8_t 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_dirnamewrite
*
* Desciption: Write the (possibly long) directory entry name.
*
* Assumption: The directory sector is in the cache.
*
****************************************************************************/
int fat_dirnamewrite(struct fat_mountpt_s *fs, struct fat_dirinfo_s *dirinfo)
{
uint8_t *direntry = dirinfo->fd_entry;
memcpy(&direntry[DIR_NAME], dirinfo->fd_name, 8+3);
#ifdef CONFIG_FLAT_LCNAMES
DIR_PUTNTRES(direntry, dirinfo->fd_ntflags);
#else
DIR_PUTNTRES(direntry, 0);
#endif
fs->fs_dirty = true;
return OK;
}
/****************************************************************************
* Name: fat_dirwrite
*
* Desciption: Write a directory entry, possibly with a long file name
*
* Assumption: The directory sector is in the cache. The caller will write
* sector information.
*
****************************************************************************/
int fat_dirwrite(struct fat_mountpt_s *fs, struct fat_dirinfo_s *dirinfo,
uint8_t attributes, uint32_t fattime)
{
uint8_t *direntry;
/* Initialize the 32-byte directory entry */
direntry = dirinfo->fd_entry;
memset(direntry, 0, DIR_SIZE);
/* Directory name info */
(void)fat_dirnamewrite(fs, dirinfo);
/* Set the attribute attribute, write time, creation time */
DIR_PUTATTRIBUTES(direntry, attributes);
/* Set the time information */
DIR_PUTWRTTIME(direntry, fattime & 0xffff);
DIR_PUTCRTIME(direntry, fattime & 0xffff);
DIR_PUTWRTDATE(direntry, fattime >> 16);
DIR_PUTCRDATE(direntry, fattime >> 16);
fs->fs_dirty = true;
return OK;
}
/****************************************************************************
* 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)
{
uint32_t fattime;
int ret;
/* Allocate a directory entry entry */
ret = fat_allocatedirentry(fs, dirinfo);
if (ret != OK)
{
/* Failed to set up directory entry */
return ret;
}
/* Write the directory entry with the current time and the ARCHIVE attribute */
fattime = fat_systime2fattime();
return fat_dirwrite(fs, dirinfo, FATATTR_ARCHIVE, fattime);
}
/****************************************************************************
* 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, bool directory)
{
struct fat_dirinfo_s dirinfo;
uint32_t dircluster;
off_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_t)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;
uint8_t *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)) * DIR_SIZE;
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' */
ret = fat_freedirentry(fs, dirinfo.fd_entry);
if (ret < 0)
{
return ret;
}
/* 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;
}
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