fs_fat32util.c

/****************************************************************************
 * fs_fat32util.c
 *
 *   Copyright (C) 2007, 2008 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;
                }