tests/suites/helpers.function

#line 2 "suites/helpers.function"
/*----------------------------------------------------------------------------*/
/* Headers */

#include <test/macros.h>

#include <stdlib.h>

#if defined(MBEDTLS_PLATFORM_C)
#include "mbedtls/platform.h"
#else
#include <stdio.h>
#define mbedtls_fprintf    fprintf
#define mbedtls_snprintf   snprintf
#define mbedtls_calloc     calloc
#define mbedtls_free       free
#define mbedtls_exit       exit
#define mbedtls_time       time
#define mbedtls_time_t     time_t
#define MBEDTLS_EXIT_SUCCESS EXIT_SUCCESS
#define MBEDTLS_EXIT_FAILURE EXIT_FAILURE
#endif

#if defined(MBEDTLS_MEMORY_BUFFER_ALLOC_C)
#include "mbedtls/memory_buffer_alloc.h"
#endif

#if defined(MBEDTLS_CHECK_PARAMS)
#include "mbedtls/platform_util.h"
#include <setjmp.h>
#endif

#ifdef _MSC_VER
#include <basetsd.h>
typedef UINT8 uint8_t;
typedef INT32 int32_t;
typedef UINT32 uint32_t;
#define strncasecmp _strnicmp
#define strcasecmp _stricmp
#else
#include <stdint.h>
#endif

#include <string.h>

#if defined(__unix__) || (defined(__APPLE__) && defined(__MACH__))
#include <unistd.h>
#include <strings.h>
#endif

/* Type for Hex parameters */
typedef struct data_tag
{
    uint8_t *   x;
    uint32_t    len;
} data_t;

/*----------------------------------------------------------------------------*/
/* Status and error constants */

#define DEPENDENCY_SUPPORTED            0   /* Dependency supported by build */
#define KEY_VALUE_MAPPING_FOUND         0   /* Integer expression found */
#define DISPATCH_TEST_SUCCESS           0   /* Test dispatch successful */

#define KEY_VALUE_MAPPING_NOT_FOUND     -1  /* Integer expression not found */
#define DEPENDENCY_NOT_SUPPORTED        -2  /* Dependency not supported */
#define DISPATCH_TEST_FN_NOT_FOUND      -3  /* Test function not found */
#define DISPATCH_INVALID_TEST_DATA      -4  /* Invalid test parameter type.
                                               Only int, string, binary data
                                               and integer expressions are
                                               allowed */
#define DISPATCH_UNSUPPORTED_SUITE      -5  /* Test suite not supported by the
                                               build */

typedef enum
{
    PARAMFAIL_TESTSTATE_IDLE = 0,           /* No parameter failure call test */
    PARAMFAIL_TESTSTATE_PENDING,            /* Test call to the parameter failure
                                             * is pending */
    PARAMFAIL_TESTSTATE_CALLED              /* The test call to the parameter
                                             * failure function has been made */
} paramfail_test_state_t;


/*----------------------------------------------------------------------------*/
/* Macros */

/**
 * \brief   This macro tests the expression passed to it as a test step or
 *          individual test in a test case.
 *
 *          It allows a library function to return a value and return an error
 *          code that can be tested.
 *
 *          When MBEDTLS_CHECK_PARAMS is enabled, calls to the parameter failure
 *          callback, MBEDTLS_PARAM_FAILED(), will be assumed to be a test
 *          failure.
 *
 *          This macro is not suitable for negative parameter validation tests,
 *          as it assumes the test step will not create an error.
 *
 *          Failing the test means:
 *          - Mark this test case as failed.
 *          - Print a message identifying the failure.
 *          - Jump to the \c exit label.
 *
 *          This macro expands to an instruction, not an expression.
 *          It may jump to the \c exit label.
 *
 * \param   TEST    The test expression to be tested.
 */
#define TEST_ASSERT( TEST )                                 \
    do {                                                    \
       if( ! (TEST) )                                       \
       {                                                    \
          test_fail( #TEST, __LINE__, __FILE__ );           \
          goto exit;                                        \
       }                                                    \
    } while( 0 )

/** Evaluate two expressions and fail the test case if they have different
 * values.
 *
 * \param expr1     An expression to evaluate.
 * \param expr2     The expected value of \p expr1. This can be any
 *                  expression, but it is typically a constant.
 */
#define TEST_EQUAL( expr1, expr2 )              \
    TEST_ASSERT( ( expr1 ) == ( expr2 ) )

/** Allocate memory dynamically and fail the test case if this fails.
 *
 * You must set \p pointer to \c NULL before calling this macro and
 * put `mbedtls_free( pointer )` in the test's cleanup code.
 *
 * If \p length is zero, the resulting \p pointer will be \c NULL.
 * This is usually what we want in tests since API functions are
 * supposed to accept null pointers when a buffer size is zero.
 *
 * This macro expands to an instruction, not an expression.
 * It may jump to the \c exit label.
 *
 * \param pointer   An lvalue where the address of the allocated buffer
 *                  will be stored.
 *                  This expression may be evaluated multiple times.
 * \param length    Number of elements to allocate.
 *                  This expression may be evaluated multiple times.
 *
 */
#define ASSERT_ALLOC( pointer, length )                           \
    do                                                            \
    {                                                             \
        TEST_ASSERT( ( pointer ) == NULL );                       \
        if( ( length ) != 0 )                                     \
        {                                                         \
            ( pointer ) = mbedtls_calloc( sizeof( *( pointer ) ), \
                                          ( length ) );           \
            TEST_ASSERT( ( pointer ) != NULL );                   \
        }                                                         \
    }                                                             \
    while( 0 )

/** Allocate memory dynamically. If the allocation fails, skip the test case.
 *
 * This macro behaves like #ASSERT_ALLOC, except that if the allocation
 * fails, it marks the test as skipped rather than failed.
 */
#define ASSERT_ALLOC_WEAK( pointer, length )                      \
    do                                                            \
    {                                                             \
        TEST_ASSERT( ( pointer ) == NULL );                       \
        if( ( length ) != 0 )                                     \
        {                                                         \
            ( pointer ) = mbedtls_calloc( sizeof( *( pointer ) ), \
                                          ( length ) );           \
            TEST_ASSUME( ( pointer ) != NULL );                   \
        }                                                         \
    }                                                             \
    while( 0 )

/** Compare two buffers and fail the test case if they differ.
 *
 * This macro expands to an instruction, not an expression.
 * It may jump to the \c exit label.
 *
 * \param p1        Pointer to the start of the first buffer.
 * \param size1     Size of the first buffer in bytes.
 *                  This expression may be evaluated multiple times.
 * \param p2        Pointer to the start of the second buffer.
 * \param size2     Size of the second buffer in bytes.
 *                  This expression may be evaluated multiple times.
 */
#define ASSERT_COMPARE( p1, size1, p2, size2 )                          \
    do                                                                  \
    {                                                                   \
        TEST_ASSERT( ( size1 ) == ( size2 ) );                          \
        if( ( size1 ) != 0 )                                            \
            TEST_ASSERT( memcmp( ( p1 ), ( p2 ), ( size1 ) ) == 0 );    \
    }                                                                   \
    while( 0 )

/**
 * \brief   This macro tests the expression passed to it and skips the
 *          running test if it doesn't evaluate to 'true'.
 *
 * \param   TEST    The test expression to be tested.
 */
#define TEST_ASSUME( TEST )                         \
    do {                                            \
        if( ! (TEST) )                              \
        {                                           \
            test_skip( #TEST, __LINE__, __FILE__ ); \
            goto exit;                              \
        }                                           \
    } while( 0 )

#if defined(MBEDTLS_CHECK_PARAMS) && !defined(MBEDTLS_PARAM_FAILED_ALT)
/**
 * \brief   This macro tests the statement passed to it as a test step or
 *          individual test in a test case. The macro assumes the test will fail
 *          and will generate an error.
 *
 *          It allows a library function to return a value and tests the return
 *          code on return to confirm the given error code was returned.
 *
 *          When MBEDTLS_CHECK_PARAMS is enabled, calls to the parameter failure
 *          callback, MBEDTLS_PARAM_FAILED(), are assumed to indicate the
 *          expected failure, and the test will pass.
 *
 *          This macro is intended for negative parameter validation tests,
 *          where the failing function may return an error value or call
 *          MBEDTLS_PARAM_FAILED() to indicate the error.
 *
 * \param   PARAM_ERROR_VALUE   The expected error code.
 *
 * \param   TEST                The test expression to be tested.
 */
#define TEST_INVALID_PARAM_RET( PARAM_ERR_VALUE, TEST )                     \
    do {                                                                    \
        test_info.paramfail_test_state = PARAMFAIL_TESTSTATE_PENDING;       \
        if( (TEST) != (PARAM_ERR_VALUE) ||                                  \
            test_info.paramfail_test_state != PARAMFAIL_TESTSTATE_CALLED )  \
        {                                                                   \
            test_fail( #TEST, __LINE__, __FILE__ );                         \
            goto exit;                                                      \
        }                                                                   \
   } while( 0 )

/**
 * \brief   This macro tests the statement passed to it as a test step or
 *          individual test in a test case. The macro assumes the test will fail
 *          and will generate an error.
 *
 *          It assumes the library function under test cannot return a value and
 *          assumes errors can only be indicated byt calls to
 *          MBEDTLS_PARAM_FAILED().
 *
 *          When MBEDTLS_CHECK_PARAMS is enabled, calls to the parameter failure
 *          callback, MBEDTLS_PARAM_FAILED(), are assumed to indicate the
 *          expected failure. If MBEDTLS_CHECK_PARAMS is not enabled, no test
 *          can be made.
 *
 *          This macro is intended for negative parameter validation tests,
 *          where the failing function can only return an error by calling
 *          MBEDTLS_PARAM_FAILED() to indicate the error.
 *
 * \param   TEST                The test expression to be tested.
 */
#define TEST_INVALID_PARAM( TEST )                                          \
    do {                                                                    \
        memcpy(jmp_tmp, param_fail_jmp, sizeof(jmp_buf));                   \
        if( setjmp( param_fail_jmp ) == 0 )                                 \
        {                                                                   \
            TEST;                                                           \
            test_fail( #TEST, __LINE__, __FILE__ );                         \
            goto exit;                                                      \
        }                                                                   \
        memcpy(param_fail_jmp, jmp_tmp, sizeof(jmp_buf));                   \
    } while( 0 )
#endif /* MBEDTLS_CHECK_PARAMS && !MBEDTLS_PARAM_FAILED_ALT */

/**
 * \brief   This macro tests the statement passed to it as a test step or
 *          individual test in a test case. The macro assumes the test will not fail.
 *
 *          It assumes the library function under test cannot return a value and
 *          assumes errors can only be indicated by calls to
 *          MBEDTLS_PARAM_FAILED().
 *
 *          When MBEDTLS_CHECK_PARAMS is enabled, calls to the parameter failure
 *          callback, MBEDTLS_PARAM_FAILED(), are assumed to indicate the
 *          expected failure. If MBEDTLS_CHECK_PARAMS is not enabled, no test
 *          can be made.
 *
 *          This macro is intended to test that functions returning void
 *          accept all of the parameter values they're supposed to accept - eg
 *          that they don't call MBEDTLS_PARAM_FAILED() when a parameter
 *          that's allowed to be NULL happens to be NULL.
 *
 *          Note: for functions that return something other that void,
 *          checking that they accept all the parameters they're supposed to
 *          accept is best done by using TEST_ASSERT() and checking the return
 *          value as well.
 *
 *          Note: this macro is available even when #MBEDTLS_CHECK_PARAMS is
 *          disabled, as it makes sense to check that the functions accept all
 *          legal values even if this option is disabled - only in that case,
 *          the test is more about whether the function segfaults than about
 *          whether it invokes MBEDTLS_PARAM_FAILED().
 *
 * \param   TEST                The test expression to be tested.
 */
#define TEST_VALID_PARAM( TEST )                                    \
    TEST_ASSERT( ( TEST, 1 ) );

#define TEST_HELPER_ASSERT(a) if( !( a ) )                          \
{                                                                   \
    mbedtls_fprintf( stderr, "Assertion Failed at %s:%d - %s\n",    \
                             __FILE__, __LINE__, #a );              \
    mbedtls_exit( 1 );                                              \
}

#if defined(__GNUC__)
/* Test if arg and &(arg)[0] have the same type. This is true if arg is
 * an array but not if it's a pointer. */
#define IS_ARRAY_NOT_POINTER( arg )                                     \
    ( ! __builtin_types_compatible_p( __typeof__( arg ),                \
                                      __typeof__( &( arg )[0] ) ) )
#else
/* On platforms where we don't know how to implement this check,
 * omit it. Oh well, a non-portable check is better than nothing. */
#define IS_ARRAY_NOT_POINTER( arg ) 1
#endif

/* A compile-time constant with the value 0. If `const_expr` is not a
 * compile-time constant with a nonzero value, cause a compile-time error. */
#define STATIC_ASSERT_EXPR( const_expr )                                \
    ( 0 && sizeof( struct { int STATIC_ASSERT : 1 - 2 * ! ( const_expr ); } ) )
/* Return the scalar value `value` (possibly promoted). This is a compile-time
 * constant if `value` is. `condition` must be a compile-time constant.
 * If `condition` is false, arrange to cause a compile-time error. */
#define STATIC_ASSERT_THEN_RETURN( condition, value )   \
    ( STATIC_ASSERT_EXPR( condition ) ? 0 : ( value ) )

#define ARRAY_LENGTH_UNSAFE( array )            \
    ( sizeof( array ) / sizeof( *( array ) ) )
/** Return the number of elements of a static or stack array.
 *
 * \param array         A value of array (not pointer) type.
 *
 * \return The number of elements of the array.
 */
#define ARRAY_LENGTH( array )                                           \
    ( STATIC_ASSERT_THEN_RETURN( IS_ARRAY_NOT_POINTER( array ),         \
                                 ARRAY_LENGTH_UNSAFE( array ) ) )

/** Return the smaller of two values.
 *
 * \param x         An integer-valued expression without side effects.
 * \param y         An integer-valued expression without side effects.
 *
 * \return The smaller of \p x and \p y.
 */
#define MIN( x, y ) ( ( x ) < ( y ) ? ( x ) : ( y ) )

/** Return the larger of two values.
 *
 * \param x         An integer-valued expression without side effects.
 * \param y         An integer-valued expression without side effects.
 *
 * \return The larger of \p x and \p y.
 */
#define MAX( x, y ) ( ( x ) > ( y ) ? ( x ) : ( y ) )

/** Allocate memory dynamically and fail the test case if this fails.
 *
 * You must set \p pointer to \c NULL before calling this macro and
 * put `mbedtls_free( pointer )` in the test's cleanup code.
 *
 * If \p length is zero, the resulting \p pointer will be \c NULL.
 * This is usually what we want in tests since API functions are
 * supposed to accept null pointers when a buffer size is zero.
 *
 * This macro expands to an instruction, not an expression.
 * It may jump to the \c exit label.
 *
 * \param pointer   An lvalue where the address of the allocated buffer
 *                  will be stored.
 *                  This expression may be evaluated multiple times.
 * \param length    Number of elements to allocate.
 *                  This expression may be evaluated multiple times.
 *
 */
#define ASSERT_ALLOC( pointer, length )                           \
    do                                                            \
    {                                                             \
        TEST_ASSERT( ( pointer ) == NULL );                       \
        if( ( length ) != 0 )                                     \
        {                                                         \
            ( pointer ) = mbedtls_calloc( sizeof( *( pointer ) ), \
                                          ( length ) );           \
            TEST_ASSERT( ( pointer ) != NULL );                   \
        }                                                         \
    }                                                             \
    while( 0 )

/*
 * 32-bit integer manipulation macros (big endian)
 */
#ifndef GET_UINT32_BE
#define GET_UINT32_BE(n,b,i)                            \
{                                                       \
    (n) = ( (uint32_t) (b)[(i)    ] << 24 )             \
        | ( (uint32_t) (b)[(i) + 1] << 16 )             \
        | ( (uint32_t) (b)[(i) + 2] <<  8 )             \
        | ( (uint32_t) (b)[(i) + 3]       );            \
}
#endif

#ifndef PUT_UINT32_BE
#define PUT_UINT32_BE(n,b,i)                            \
{                                                       \
    (b)[(i)    ] = (unsigned char) ( (n) >> 24 );       \
    (b)[(i) + 1] = (unsigned char) ( (n) >> 16 );       \
    (b)[(i) + 2] = (unsigned char) ( (n) >>  8 );       \
    (b)[(i) + 3] = (unsigned char) ( (n)       );       \
}
#endif


/*----------------------------------------------------------------------------*/
/* Global variables */

typedef enum
{
    TEST_RESULT_SUCCESS = 0,
    TEST_RESULT_FAILED,
    TEST_RESULT_SKIPPED
} test_result_t;

typedef struct
{
    paramfail_test_state_t paramfail_test_state;
    test_result_t result;
    const char *test;
    const char *filename;
    int line_no;
    unsigned long step;
}
test_info_t;
static test_info_t test_info;

#if defined(MBEDTLS_PLATFORM_C)
static mbedtls_platform_context platform_ctx;
#endif

#if defined(MBEDTLS_CHECK_PARAMS)
jmp_buf param_fail_jmp;
jmp_buf jmp_tmp;
#endif

/*----------------------------------------------------------------------------*/
/* Helper flags for complex dependencies */

/* Indicates whether we expect mbedtls_entropy_init
 * to initialize some strong entropy source. */
#if defined(MBEDTLS_TEST_NULL_ENTROPY) ||             \
    ( !defined(MBEDTLS_NO_DEFAULT_ENTROPY_SOURCES) && \
      ( !defined(MBEDTLS_NO_PLATFORM_ENTROPY)  ||     \
         defined(MBEDTLS_HAVEGE_C)             ||     \
         defined(MBEDTLS_ENTROPY_HARDWARE_ALT) ||     \
         defined(ENTROPY_NV_SEED) ) )
#define ENTROPY_HAVE_STRONG
#endif


/*----------------------------------------------------------------------------*/
/* Helper Functions */

/** Set the test step number for failure reports.
 *
 * Call this function to display "step NNN" in addition to the line number
 * and file name if a test fails. Typically the "step number" is the index
 * of a for loop but it can be whatever you want.
 *
 * \param step  The step number to report.
 */
void test_set_step( unsigned long step )
{
    test_info.step = step;
}

void test_fail( const char *test, int line_no, const char* filename )
{
    test_info.result = TEST_RESULT_FAILED;
    test_info.test = test;
    test_info.line_no = line_no;
    test_info.filename = filename;
}

void test_skip( const char *test, int line_no, const char* filename )
{
    test_info.result = TEST_RESULT_SKIPPED;
    test_info.test = test;
    test_info.line_no = line_no;
    test_info.filename = filename;
}

int platform_setup()
{
    int ret = 0;
#if defined(MBEDTLS_PLATFORM_C)
    ret = mbedtls_platform_setup( &platform_ctx );
#endif /* MBEDTLS_PLATFORM_C */
    return( ret );
}

void platform_teardown()
{
#if defined(MBEDTLS_PLATFORM_C)
    mbedtls_platform_teardown( &platform_ctx );
#endif /* MBEDTLS_PLATFORM_C */
}

#if defined(MBEDTLS_CHECK_PARAMS)
void mbedtls_param_failed( const char *failure_condition,
                           const char *file,
                           int line )
{
    /* If we are testing the callback function...  */
    if( test_info.paramfail_test_state == PARAMFAIL_TESTSTATE_PENDING )
    {
        test_info.paramfail_test_state = PARAMFAIL_TESTSTATE_CALLED;
    }
    else
    {
        /* ...else we treat this as an error */

        /* Record the location of the failure, but not as a failure yet, in case
         * it was part of the test */
        test_fail( failure_condition, line, file );
        test_info.result = TEST_RESULT_SUCCESS;

        longjmp( param_fail_jmp, 1 );
    }
}
#endif

#if defined(__unix__) || (defined(__APPLE__) && defined(__MACH__))
static int redirect_output( FILE** out_stream, const char* path )
{
    int stdout_fd = dup( fileno( *out_stream ) );

    if( stdout_fd == -1 )
    {
        return -1;
    }

    fflush( *out_stream );
    fclose( *out_stream );
    *out_stream = fopen( path, "w" );

    if( *out_stream == NULL )
    {
        close( stdout_fd );
        return -1;
    }

    return stdout_fd;
}

static int restore_output( FILE** out_stream, int old_fd )
{
    fflush( *out_stream );
    fclose( *out_stream );

    *out_stream = fdopen( old_fd, "w" );
    if( *out_stream == NULL )
    {
        return -1;
    }

    return 0;
}

static void close_output( FILE* out_stream )
{
    fclose( out_stream );
}
#endif /* __unix__ || __APPLE__ __MACH__ */

int unhexify( unsigned char *obuf, const char *ibuf )
{
    unsigned char c, c2;
    int len = strlen( ibuf ) / 2;
    TEST_HELPER_ASSERT( strlen( ibuf ) % 2 == 0 ); /* must be even number of bytes */

    while( *ibuf != 0 )
    {
        c = *ibuf++;
        if( c >= '0' && c <= '9' )
            c -= '0';
        else if( c >= 'a' && c <= 'f' )
            c -= 'a' - 10;
        else if( c >= 'A' && c <= 'F' )
            c -= 'A' - 10;
        else
            TEST_HELPER_ASSERT( 0 );

        c2 = *ibuf++;
        if( c2 >= '0' && c2 <= '9' )
            c2 -= '0';
        else if( c2 >= 'a' && c2 <= 'f' )
            c2 -= 'a' - 10;
        else if( c2 >= 'A' && c2 <= 'F' )
            c2 -= 'A' - 10;
        else
            TEST_HELPER_ASSERT( 0 );

        *obuf++ = ( c << 4 ) | c2;
    }

    return len;
}

void hexify( unsigned char *obuf, const unsigned char *ibuf, int len )
{
    unsigned char l, h;

    while( len != 0 )
    {
        h = *ibuf / 16;
        l = *ibuf % 16;

        if( h < 10 )
            *obuf++ = '0' + h;
        else
            *obuf++ = 'a' + h - 10;

        if( l < 10 )
            *obuf++ = '0' + l;
        else
            *obuf++ = 'a' + l - 10;

        ++ibuf;
        len--;
    }
}

/**
 * Allocate and zeroize a buffer.
 *
 * If the size if zero, a pointer to a zeroized 1-byte buffer is returned.
 *
 * For convenience, dies if allocation fails.
 */
unsigned char *zero_alloc( size_t len )
{
    void *p;
    size_t actual_len = ( len != 0 ) ? len : 1;

    p = mbedtls_calloc( 1, actual_len );
    TEST_HELPER_ASSERT( p != NULL );

    memset( p, 0x00, actual_len );

    return( p );
}

/**
 * Allocate and fill a buffer from hex data.
 *
 * The buffer is sized exactly as needed. This allows to detect buffer
 * overruns (including overreads) when running the test suite under valgrind.
 *
 * If the size if zero, a pointer to a zeroized 1-byte buffer is returned.
 *
 * For convenience, dies if allocation fails.
 */
unsigned char *unhexify_alloc( const char *ibuf, size_t *olen )
{
    unsigned char *obuf;

    *olen = strlen( ibuf ) / 2;

    if( *olen == 0 )
        return( zero_alloc( *olen ) );

    obuf = mbedtls_calloc( 1, *olen );
    TEST_HELPER_ASSERT( obuf != NULL );

    (void) unhexify( obuf, ibuf );

    return( obuf );
}

/**
 * This function just returns data from rand().
 * Although predictable and often similar on multiple
 * runs, this does not result in identical random on
 * each run. So do not use this if the results of a
 * test depend on the random data that is generated.
 *
 * rng_state shall be NULL.
 */
int rnd_std_rand( void *rng_state, unsigned char *output, size_t len )
{
#if !defined(__OpenBSD__)
    size_t i;

    if( rng_state != NULL )
        rng_state  = NULL;

    for( i = 0; i < len; ++i )
        output[i] = rand();
#else
    if( rng_state != NULL )
        rng_state = NULL;

    arc4random_buf( output, len );
#endif /* !OpenBSD */

    return( 0 );
}

/**
 * This function only returns zeros
 *
 * rng_state shall be NULL.
 */
int rnd_zero_rand( void *rng_state, unsigned char *output, size_t len )
{
    if( rng_state != NULL )
        rng_state  = NULL;

    memset( output, 0, len );

    return( 0 );
}

typedef struct
{
    unsigned char *buf;
    size_t length;
} rnd_buf_info;

/**
 * This function returns random based on a buffer it receives.
 *
 * rng_state shall be a pointer to a rnd_buf_info structure.
 *
 * The number of bytes released from the buffer on each call to
 * the random function is specified by per_call. (Can be between
 * 1 and 4)
 *
 * After the buffer is empty it will return rand();
 */
int rnd_buffer_rand( void *rng_state, unsigned char *output, size_t len )
{
    rnd_buf_info *info = (rnd_buf_info *) rng_state;
    size_t use_len;

    if( rng_state == NULL )
        return( rnd_std_rand( NULL, output, len ) );

    use_len = len;
    if( len > info->length )
        use_len = info->length;

    if( use_len )
    {
        memcpy( output, info->buf, use_len );
        info->buf += use_len;
        info->length -= use_len;
    }

    if( len - use_len > 0 )
        return( rnd_std_rand( NULL, output + use_len, len - use_len ) );

    return( 0 );
}

/**
 * Info structure for the pseudo random function
 *
 * Key should be set at the start to a test-unique value.
 * Do not forget endianness!
 * State( v0, v1 ) should be set to zero.
 */
typedef struct
{
    uint32_t key[16];
    uint32_t v0, v1;
} rnd_pseudo_info;

/**
 * This function returns random based on a pseudo random function.
 * This means the results should be identical on all systems.
 * Pseudo random is based on the XTEA encryption algorithm to
 * generate pseudorandom.
 *
 * rng_state shall be a pointer to a rnd_pseudo_info structure.
 */
int rnd_pseudo_rand( void *rng_state, unsigned char *output, size_t len )
{
    rnd_pseudo_info *info = (rnd_pseudo_info *) rng_state;
    uint32_t i, *k, sum, delta=0x9E3779B9;
    unsigned char result[4], *out = output;

    if( rng_state == NULL )
        return( rnd_std_rand( NULL, output, len ) );

    k = info->key;

    while( len > 0 )
    {
        size_t use_len = ( len > 4 ) ? 4 : len;
        sum = 0;

        for( i = 0; i < 32; i++ )
        {
            info->v0 += ( ( ( info->v1 << 4 ) ^ ( info->v1 >> 5 ) )
                            + info->v1 ) ^ ( sum + k[sum & 3] );
            sum += delta;
            info->v1 += ( ( ( info->v0 << 4 ) ^ ( info->v0 >> 5 ) )
                            + info->v0 ) ^ ( sum + k[( sum>>11 ) & 3] );
        }

        PUT_UINT32_BE( info->v0, result, 0 );
        memcpy( out, result, use_len );
        len -= use_len;
        out += 4;
    }

    return( 0 );
}

int hexcmp( uint8_t * a, uint8_t * b, uint32_t a_len, uint32_t b_len )
{
    int ret = 0;
    uint32_t i = 0;

    if( a_len != b_len )
        return( -1 );

    for( i = 0; i < a_len; i++ )
    {
        if( a[i] != b[i] )
        {
            ret = -1;
            break;
        }
    }
    return ret;
}