ff_sys.c

/*
 * FreeRTOS+FAT V2.3.3
 * Copyright (C) 2021 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 * https://www.FreeRTOS.org
 * https://github.com/FreeRTOS
 *
 */

#include <stdio.h>
#include <string.h>

/* FreeRTOS includes. */
#include "FreeRTOS.h"
#include "task.h"
#include "portable.h"

#include "ff_headers.h"
#include "ff_sys.h"

#ifndef ARRAY_SIZE
    #define  ARRAY_SIZE( x )    ( int ) ( sizeof( x ) / sizeof( x )[ 0 ] )
#endif

/*
 * Define a collection of 'file systems' as a simple array
 */
typedef struct xSYSTEM
{
    FF_SubSystem_t xSystems[ ffconfigMAX_FILE_SYS ];
    volatile BaseType_t xFileSystemCount;
} ff_sys_t;


static ff_sys_t file_systems;
static const char rootDir[] = "/";

int FF_FS_Count( void )
{
    return ( int ) file_systems.xFileSystemCount;
}
/*-----------------------------------------------------------*/

void FF_FS_Init( void )
{
    memset( &file_systems, '\0', sizeof( file_systems ) );

    /* There is always a root file system, even if it doesn't have a
     * IO manager. */
    file_systems.xFileSystemCount = ( BaseType_t ) 1;
    /* Set to "/", second byte is already zero. */
    file_systems.xSystems[ 0 ].pcPath[ 0 ] = ( char ) '/';

    file_systems.xSystems[ 0 ].xPathlen = 1;
}
/*-----------------------------------------------------------*/

int FF_FS_Add( const char * pcPath,
               FF_Disk_t * pxDisk )
{
    int iReturn = pdFALSE;

    configASSERT( pxDisk );

    if( *pcPath != ( char ) '/' )
    {
        FF_PRINTF( "FF_FS_Add: Need a \"/\": '%s'\n", pcPath );
    }
    else
    {
        BaseType_t xUseIndex = -1;
        size_t uxPathLength = strlen( pcPath );

        vTaskSuspendAll();
        {
            if( file_systems.xFileSystemCount == ( BaseType_t ) 0 )
            {
                FF_FS_Init();
            }

            if( uxPathLength == ( size_t ) 1u )
            {
                /* This is the "/" path
                 * and will always be put at index 0 */
                xUseIndex = ( BaseType_t ) 0;
            }
            else
            {
                BaseType_t xIndex, xFreeIndex = -1;
                FF_SubSystem_t * pxSubSystem = file_systems.xSystems + 1; /* Skip the root entry */

                for( xIndex = ( BaseType_t ) 1; xIndex < file_systems.xFileSystemCount; xIndex++, pxSubSystem++ )
                {
                    if( ( pxSubSystem->xPathlen == ( BaseType_t ) uxPathLength ) &&
                        ( memcmp( pxSubSystem->pcPath, pcPath, uxPathLength ) == 0 ) )
                    {
                        /* A system is updated with a new handler. */
                        xUseIndex = xIndex;
                        break;
                    }

                    if( ( pxSubSystem->pxManager == NULL ) && ( xFreeIndex < 0 ) )
                    {
                        /* Remember the first free slot. */
                        xFreeIndex = xIndex;
                    }
                }

                if( xUseIndex < ( BaseType_t ) 0 )
                {
                    if( xFreeIndex >= ( BaseType_t ) 0 )
                    {
                        /* Use the first free slot. */
                        xUseIndex = xFreeIndex;
                    }
                    else if( file_systems.xFileSystemCount < ARRAY_SIZE( file_systems.xSystems ) )
                    {
                        /* Fill a new entry. */
                        xUseIndex = file_systems.xFileSystemCount++;
                    }
                }
            } /* uxPathLength != 1 */

            if( xUseIndex >= ( BaseType_t ) 0 )
            {
                iReturn = pdTRUE;
                strncpy( file_systems.xSystems[ xUseIndex ].pcPath, pcPath, sizeof( file_systems.xSystems[ xUseIndex ].pcPath ) - 1 );
                file_systems.xSystems[ xUseIndex ].pcPath[ sizeof( file_systems.xSystems[ xUseIndex ].pcPath ) - 1 ] = 0;
                file_systems.xSystems[ xUseIndex ].xPathlen = ( BaseType_t ) uxPathLength;
                file_systems.xSystems[ xUseIndex ].pxManager = pxDisk->pxIOManager;
            }
        }
        xTaskResumeAll();

        if( iReturn == pdFALSE )
        {
            FF_PRINTF( "FF_FS_Add: Table full '%s' (max = %d)\n", pcPath, ( int ) ARRAY_SIZE( file_systems.xSystems ) );
        }
    }

    return iReturn;
}
/*-----------------------------------------------------------*/

void FF_FS_Remove( const char * pcPath )
{
    BaseType_t xUseIndex, xIndex;
    size_t uxPathLength;

    if( pcPath[ 0 ] == ( char ) '/' )
    {
        xUseIndex = -1;
        uxPathLength = strlen( pcPath );

        /* Is it the "/" path ? */
        if( uxPathLength == ( size_t ) 1u )
        {
            xUseIndex = 0;
        }
        else
        {
            FF_SubSystem_t * pxSubSystem = file_systems.xSystems + 1;

            for( xIndex = 1; xIndex < file_systems.xFileSystemCount; xIndex++, pxSubSystem++ )
            {
                if( ( pxSubSystem->xPathlen == ( BaseType_t ) uxPathLength ) &&
                    ( memcmp( pxSubSystem->pcPath, pcPath, uxPathLength ) == 0 ) )
                {
                    xUseIndex = xIndex;
                    break;
                }
            }
        }

        if( xUseIndex >= 0 )
        {
            vTaskSuspendAll();
            {
                file_systems.xSystems[ xUseIndex ].pxManager = NULL;
                file_systems.xSystems[ xUseIndex ].xPathlen = ( BaseType_t ) 0;

                for( xIndex = file_systems.xFileSystemCount - 1; xIndex > 0; xIndex-- )
                {
                    if( file_systems.xSystems[ xIndex ].pxManager != NULL )
                    {
                        /* The slot at 'xIndex' is still in use. */
                        break;
                    }
                }

                file_systems.xFileSystemCount = xIndex + 1;
            }
            xTaskResumeAll();
        }
    }
}
/*-----------------------------------------------------------*/

int FF_FS_Find( const char * pcPath,
                FF_DirHandler_t * pxHandler )
{
    FF_SubSystem_t * pxSubSystem;
    size_t uxPathLength;
    BaseType_t xUseIndex;
    int iReturn;

    pxSubSystem = file_systems.xSystems + 1;
    uxPathLength = strlen( pcPath );

    memset( pxHandler, '\0', sizeof( *pxHandler ) );

    for( xUseIndex = 1; xUseIndex < file_systems.xFileSystemCount; xUseIndex++, pxSubSystem++ )
    {
        if( ( uxPathLength >= ( size_t ) pxSubSystem->xPathlen ) &&
            ( memcmp( pxSubSystem->pcPath, pcPath, ( size_t ) pxSubSystem->xPathlen ) == 0 ) &&
            ( ( pcPath[ pxSubSystem->xPathlen ] == '\0' ) || ( pcPath[ pxSubSystem->xPathlen ] == '/' ) ) ) /* System "/ram" should not match with "/ramc/etc". */
        {
            if( pcPath[ pxSubSystem->xPathlen ] == '\0' )
            {
                pxHandler->pcPath = rootDir;
            }
            else
            {
                pxHandler->pcPath = pcPath + pxSubSystem->xPathlen;
            }

            pxHandler->pxManager = pxSubSystem->pxManager;
            break;
        }
    }

    if( xUseIndex == file_systems.xFileSystemCount )
    {
        pxHandler->pcPath = pcPath;
        pxHandler->pxManager = file_systems.xSystems[ 0 ].pxManager;
    }

    if( FF_Mounted( pxHandler->pxManager ) )
    {
        iReturn = pdTRUE;
    }
    else
    {
        iReturn = pdFALSE;
    }

    return iReturn;
}
/*-----------------------------------------------------------*/

int FF_FS_Get( int xIndex,
               FF_SubSystem_t * pxSystem )
{
    int iReturn;

    /* Get a copy of a fs info. */
    if( ( xIndex < 0 ) || ( xIndex >= file_systems.xFileSystemCount ) )
    {
        iReturn = pdFALSE;
    }
    else
    {
        /* Note: it will copy the contents of 'FF_SubSystem_t'. */
        *pxSystem = file_systems.xSystems[ xIndex ];
        iReturn = pdTRUE;
    }

    return iReturn;
}
/*-----------------------------------------------------------*/