dosfsfmtlib.c

vxworks操作系统的文件系统部分原代码

* 
* .IP DOS_OPT_BLANK	
* Disregard the current volume parameters, and calculate new parameters
* based only on disk size.
*
* .IP DOS_OPT_QUIET
* Do not produce any diagnostic output during formatting.
*
* .IP DOS_OPT_FAT16
* Format the volume with FAT16 format even if the disk is larger then 
* 2 Gbytes, which would normally be formatted with FAT32.
*
* .IP DOS_OPT_FAT32
* Format the volume with FAT32, even if the disk is smaller then 
* 2 Gbytes, but is larger then 512 Mbytes.
*
* .IP DOS_OPT_VXLONGNAMES
* Format the volume to use Wind River proprietary case-sensitive Long
* File Names. Note that this format is incompatible with any other
* implementation of the MS-DOS file system.
*
* .LP
* The third argument, <pPromptFunc> is an optional pointer to a function
* that may interactively prompt the user to change any of the
* modifiable volume parameters before formatting:
*
* .CS
* void formatPromptFunc( DOS_VOL_CONFIG *pConfig );
* .CE
*
* The <*pConfig> structure upon entry to formatPromptFunc() will contain
* the initial volume parameters, some of which can be changed before it
* returns. <pPromptFunc> should be NULL if no interactive prompting is
* required.
*
* COMPATIBILITY
*
* Although this routine tries to format the disk to be
* compatibile with Microsoft implementations of the FAT and FAT32
* file systems, there may be differences which are not under WRS
* control.  For this reason, it is highly recommended that any
* disks which are expected to be interchanged between vxWorks and
* Windows should be formatted under Windows to provide the best
* interchangeability.  The WRS implementation is more flexible,
* and should be able to handle the differences when formatting is
* done on Windows, but Windows implementations may not be able to
* handle minor differences between their implementation and ours.
*
* AVAILABILITY
* This function is an optional part of the MS-DOS file system,
* and may be included in a target system if it is required to
* be able to format new volumes.
*
* RETURNS: OK or ERROR if was unable to format the disk.
*/
STATUS dosFsVolFormat
    (
    void * 	device,		/* device name or volume or CBIO pointer */
    int		opt,		/* bit-wise or'ed options */
    FUNCPTR	pPromptFunc	/* interactive parameter change callback */
    )
    {
    DOS_VOL_CONFIG cfg, cfgOld;
    CBIO_DEV_ID	   cbioDev = NULL;
    STATUS         stat    = ERROR;
    char *         pTail;
    BOOL           preserve;
    CBIO_PARAMS    cbioParams;

    /* 
     * Determine what type of device handle we were passed,
     * and extract the CBIO pointer.
     */

    /* NULL is presumed to be an invalid device */

    if (NULL == device)
        {
        errno = S_cbioLib_INVALID_CBIO_DEV_ID;
        return (ERROR);
        }

    /*
     * check for 'device' being a valid DOS_VOLUME_DESC_ID or a CBIO_DEV_ID
     * SPR#71720 : Ensure the pointer is aligned before attempting to access
     * any structure member from it.  Avoid exception on SH arch w/DIAB.
     * cbioDevVerify() will do an alignment check internally. The check
     * "((DOS_VOLUME_DESC_ID)device)->magic" needs _WRS_ALIGN_CHECK().
     */

    if (OK == cbioDevVerify ((CBIO_DEV_ID) device))
        {
        /* 'device' is a valid CBIO_DEV_ID */

        cbioDev = device;
        }
    else if (TRUE == _WRS_ALIGN_CHECK(device, DOS_VOLUME_DESC))
        {
        if (DOS_FS_MAGIC == ((DOS_VOLUME_DESC_ID)device)->magic)
            {
            /*
             * 'device' a valid DOS_VOLUME_DESC_ID, use its cbio ptr
             * Note that it will be cbioDevVerify()'d again below.
             */

            cbioDev = ((DOS_VOLUME_DESC_ID)device)->pCbio;
            }
        }

    if (NULL == cbioDev)
        {
        /*
         * didn't find anything valid above. Last try an iosDevFind()
         * to see if 'device' is a character string, an io device name.
         */

#ifdef _WRS_DOSFS2_VXWORKS_AE

        cbioDev = (CBIO_DEV_ID) iosDevFind((char *) device, 
                                           (const char **)&pTail );

#else

        cbioDev = (CBIO_DEV_ID) iosDevFind((char *) device, 
                                           (char **)&pTail );

#endif /* _WRS_DOSFS2_VXWORKS_AE */

        if( (NULL == cbioDev) || (pTail == device) )
            {
            /* 'device' appears invalid, so we bail out */
            errno = S_cbioLib_INVALID_CBIO_DEV_ID;
            return (ERROR);
            }

        if (TRUE == _WRS_ALIGN_CHECK(cbioDev, DOS_VOLUME_DESC))
            {
            if( ((DOS_VOLUME_DESC_ID)cbioDev)->magic != DOS_FS_MAGIC )
                {
                /* 'device' appears invalid, so we bail out */

                errno = S_cbioLib_INVALID_CBIO_DEV_ID;
                return (ERROR);
                }
            else
                {
                /* 
                 * 'cbioDev' is now a valid DOS_VOLUME_DESC_ID, use its CBIO
                 * PTR. Note that it will be cbioDevVerify()'d again below.
                 */

	        cbioDev = ((DOS_VOLUME_DESC_ID)cbioDev)->pCbio;
                }
            }
        }


    /* Again, verify that we have a valid CBIO handle */

    if( ERROR == cbioDevVerify(cbioDev))
	{
	return (ERROR);
	}
    else
	{
        /* 
         * SPR#71633: cbioDevVerify() may have set errno 
         * above, but if we made it here, then it doesn't 
         * matter to the user, so we clear any errno.
         */
        errno = 0;
	}

    /* clear the DOS_VOL_CONFIG structures */

    bzero( (caddr_t) &cfg, sizeof(cfg));
    bzero( (caddr_t) &cfgOld, sizeof(cfgOld));

    /* take ownership of the device */

    if( ERROR == cbioLock (cbioDev, WAIT_FOREVER))
	return ERROR;

    /* RESET the CBIO device */

    if( cbioIoctl( cbioDev, CBIO_RESET, 0) != OK )
	goto _done_;

    /* Ensure we can write to this CBIO device */

    if( O_RDONLY == cbioModeGet(cbioDev))
	{
	errno = S_dosFsLib_READ_ONLY ;
	goto _done_;
	}

    /* Get the underlying CBIO device parameters */

    if (ERROR == cbioParamsGet (cbioDev, &cbioParams))
	{
        stat = ERROR;
	goto _done_;
	}

    /* set hidden to sectors per track for hard disk */

    /*  
     * jkf The below is a hack. The boot sectors nHidden field should be 
     * set to the same value as the Relative Sector field in the MS 
     * partition table that defines the location of this volume.  This 
     * is not being handled here or in usrFdiskPartCreate.  Somehow 
     * usrFdiskPartLib.c and dpartCbio.c, should account for this someday.  
     * The value is also typically equal to the sectors per track value.  
     * Don't like the below code at all, it assumes too much.
     */

    if (36 <  cbioParams.blocksPerTrack) /* 36=2.88 floppy*/
	{
	if ((block_t)cbioParams.blockOffset <= 
            (block_t)cbioParams.blocksPerTrack) 
	    {
            cfgOld.nHidden = cbioParams.blockOffset;
            cfg.nHidden = cbioParams.blockOffset;
	    }
	else
	    {
            cfgOld.nHidden = cbioParams.blocksPerTrack;
            cfg.nHidden = cbioParams.blocksPerTrack;
	    }
	}
    else
	{
        cfgOld.nHidden = 0;
        cfg.nHidden = 0;
	}

    /* read the existing boot block from the disk. */

    stat = dosFsFmtReadBootBlock( cbioDev, &cfgOld );

    if((opt & DOS_OPT_QUIET) == 0)
	{
	printf("Retrieved old volume params with %%%d confidence:\n", stat );
	dosFsFmtShow(&cfgOld);
	}

   switch (opt & (DOS_OPT_BLANK | DOS_OPT_PRESERVE))
	{
	default:
	    /* preserve if well structured boot block uncovered */
	    if( stat < 90 )
		{
		cfg.volSerial = cfgOld.volSerial ;
		bcopy(cfgOld.volLabel, cfg.volLabel, sizeof(cfg.volLabel)) ;
		preserve = FALSE ;
		}
	    else
		{
		cfg = cfgOld ;
		preserve = TRUE ;
		}
	    break ;
	case DOS_OPT_PRESERVE: /* preserve if not totally corrupt */
	    if( stat < 70 )
		{
		cfg.volSerial = cfgOld.volSerial ;
		bcopy(cfgOld.volLabel, cfg.volLabel, sizeof(cfg.volLabel)) ;
		preserve = FALSE ;
		}
	    else
		{
		cfg = cfgOld ;
		preserve = TRUE ;
		}
	    break ;
	case DOS_OPT_BLANK: /* never preserve */
	    cfg.volSerial = cfgOld.volSerial ;
	    bcopy(cfg.volLabel, cfgOld.volLabel, sizeof(cfgOld.volLabel)) ;
	    preserve = FALSE ;
	    break ;
	    
	}

    /* forcing FAT32 or FAT16 */

    if( opt & DOS_OPT_FAT32 )
	cfg.fatType = _FAT32 ;
    else if( opt & DOS_OPT_FAT16 )
	cfg.fatType = _FAT16 ;

    /* calculate the BPB */
    stat = dosFsFmtAutoParams( &cfg,
	cbioParams.nBlocks, cbioParams.bytesPerBlk, opt );

    if( pPromptFunc != NULL )
	{
	/* interactive prompting */
	(void) (*pPromptFunc)( &cfg );
	stat = dosFsFmtAutoParams( &cfg,
	    cbioParams.nBlocks, cbioParams.bytesPerBlk, opt );
	}

    if((opt & DOS_OPT_QUIET) == 0)
	{
	printf("Disk with %ld sectors of %d bytes will be formatted with:\n",
	    cbioParams.nBlocks, (int) cbioParams.bytesPerBlk );
	dosFsFmtShow(&cfg);
	}

    if(stat != OK)
	{
	printErr("dosFsVolFormat: bad format parameters, errno = %#x\n",
		errno );
	goto _done_;
	}

    stat = dosFsFmtVolInit( cbioDev, &cfg, preserve, opt );

    /* flush and invalidate cache immediately */
    stat |= cbioIoctl( cbioDev, CBIO_CACHE_INVAL, 0) ;

    if(stat != OK)
	{
	printErr("dosFsVolFormat: format failed, errno=%#x\n", errno );
	}

    cbioRdyChgdSet (cbioDev, TRUE);	/* force re-mount */

_done_:
    cbioUnlock (cbioDev) ;
    return stat ;
    }

/*******************************************************************************
*
* dosFsFmtLibInit - initialize the MS-DOS formatting library
*
* This function is called to optionally enable the formatting
* functionality from dosFsLib.
*
* SEE ALSO: dosFsLib
*
* NOMANUAL
*/
void dosFsFmtLibInit( void )
    {
    dosFsVolFormatRtn = dosFsVolFormat;
    }


#ifdef	__unused__ 
/*******************************************************************************
*
* dosFsFmtTest - UNITEST CODE
*
* NOMANUAL
*/
void dosFsFmtTest( int size)
    {
    DOS_VOL_CONFIG cfg;
    ULONG i, k ;
    STATUS stat ;

    if( size != 0 )
	{
	i = size ;
	bzero((caddr_t) &cfg, sizeof(cfg));
	stat = dosFsFmtAutoParams( &cfg, i, 512, 0) ;
	dosFsFmtShow( &cfg );
	if( stat == ERROR )
	    perror("dosFsFmtAutoParams");
	return;
	}

    i = 100 ;

    for(k=0; k< 1000; k++ )
	{
	bzero((caddr_t) &cfg, sizeof(cfg));
	i += rand() ;
	stat = dosFsFmtAutoParams( &cfg, i, 512, 0) ;
	dosFsFmtShow( &cfg );
	if( stat == ERROR )
	    {
	    perror("dosFsFmtAutoParams");
	    return;
	    }
	}
    }

#endif	/* __unused__ */