wolfSSL Error Handling and Reporting

Functions
WOLFSSL_API int	wolfSSL_Debugging_ON (void)
	If logging has been enabled at build time this function turns on logging at runtime. To enable logging at build time use –enable-debug or define DEBUG_WOLFSSL.
WOLFSSL_API void	wolfSSL_Debugging_OFF (void)
	This function turns off runtime logging messages. If they’re already off, no action is taken.
WOLFSSL_API int	wolfSSL_get_error (WOLFSSL *, int)
	This function returns a unique error code describing why the previous API function call (wolfSSL_connect, wolfSSL_accept, wolfSSL_read, wolfSSL_write, etc.) resulted in an error return code (SSL_FAILURE). The return value of the previous function is passed to wolfSSL_get_error through ret. After wolfSSL_get_error is called and returns the unique error code, wolfSSL_ERR_error_string() may be called to get a human-readable error string. See wolfSSL_ERR_error_string() for more information.
WOLFSSL_API void	wolfSSL_load_error_strings (void)
	This function is for OpenSSL compatibility (SSL_load_error_string) only and takes no action.
WOLFSSL_API char *	wolfSSL_ERR_error_string (unsigned long, char *)
	This function converts an error code returned by wolfSSL_get_error() into a more human-readable error string. errNumber is the error code returned by wolfSSL_get_error() and data is the storage buffer which the error string will be placed in. The maximum length of data is 80 characters by default, as defined by MAX_ERROR_SZ is wolfssl/wolfcrypt/error.h.
WOLFSSL_API void	wolfSSL_ERR_error_string_n (unsigned long e, char *buf, unsigned long sz)
	This function is a version of wolfSSL_ERR_error_string() where len specifies the maximum number of characters that may be written to buf. Like wolfSSL_ERR_error_string(), this function converts an error code returned from wolfSSL_get_error() into a more human-readable error string. The human-readable string is placed in buf.
WOLFSSL_API void	wolfSSL_ERR_print_errors_fp (FILE *, int err)
	This function converts an error code returned by wolfSSL_get_error() into a more human-readable error string and prints that string to the output file - fp. err is the error code returned by wolfSSL_get_error() and fp is the file which the error string will be placed in.
WOLFSSL_API void	wolfSSL_ERR_print_errors_cb (int(*cb)(const char *str, size_t len, void *u), void *u)
	This function uses the provided callback to handle error reporting. The callback function is executed for each error line. The string, length, and userdata are passed into the callback parameters.
WOLFSSL_API int	wolfSSL_want_read (WOLFSSL *)
	This function is similar to calling wolfSSL_get_error() and getting SSL_ERROR_WANT_READ in return. If the underlying error state is SSL_ERROR_WANT_READ, this function will return 1, otherwise, 0.
WOLFSSL_API int	wolfSSL_want_write (WOLFSSL *)
	This function is similar to calling wolfSSL_get_error() and getting SSL_ERROR_WANT_WRITE in return. If the underlying error state is SSL_ERROR_WANT_WRITE, this function will return 1, otherwise, 0.
WOLFSSL_API unsigned long	wolfSSL_ERR_peek_last_error (void)
	This function returns the absolute value of the last error from WOLFSSL_ERROR encountered.

Detailed Description

Function Documentation

wolfSSL_Debugging_OFF()

WOLFSSL_API void wolfSSL_Debugging_OFF

(

void

)

This function turns off runtime logging messages. If they’re already off, no action is taken.

Returns

none No returns.

Parameters

none	No parameters.

Example

wolfSSL_Debugging_OFF();

See also

wolfSSL_Debugging_ON

wolfSSL_SetLoggingCb

wolfSSL_Debugging_ON()

WOLFSSL_API int wolfSSL_Debugging_ON

(

void

)

If logging has been enabled at build time this function turns on logging at runtime. To enable logging at build time use –enable-debug or define DEBUG_WOLFSSL.

Returns

0 upon success.

NOT_COMPILED_IN is the error that will be returned if logging isn’t enabled for this build.

Parameters

none	No parameters.

Example

wolfSSL_Debugging_ON();

See also

wolfSSL_Debugging_OFF

wolfSSL_SetLoggingCb

wolfSSL_ERR_error_string()

WOLFSSL_API char * wolfSSL_ERR_error_string	(	unsigned long	errNumber,
		char *	data )

This function converts an error code returned by wolfSSL_get_error() into a more human-readable error string. errNumber is the error code returned by wolfSSL_get_error() and data is the storage buffer which the error string will be placed in. The maximum length of data is 80 characters by default, as defined by MAX_ERROR_SZ is wolfssl/wolfcrypt/error.h.

Returns

success On successful completion, this function returns the same string as is returned in data.

failure Upon failure, this function returns a string with the appropriate failure reason, msg.

Parameters

errNumber	error code returned by wolfSSL_get_error().
data	output buffer containing human-readable error string matching errNumber.

Example

int err = 0;
WOLFSSL* ssl;
char buffer[80];
...
err = wolfSSL_get_error(ssl, 0);
wolfSSL_ERR_error_string(err, buffer);
printf(“err = %d, %s\n”, err, buffer);

See also

wolfSSL_get_error

wolfSSL_ERR_error_string_n

wolfSSL_ERR_print_errors_fp

wolfSSL_load_error_strings

wolfSSL_ERR_error_string_n()

WOLFSSL_API void wolfSSL_ERR_error_string_n	(	unsigned long	e,
		char *	buf,
		unsigned long	sz )

This function is a version of wolfSSL_ERR_error_string() where len specifies the maximum number of characters that may be written to buf. Like wolfSSL_ERR_error_string(), this function converts an error code returned from wolfSSL_get_error() into a more human-readable error string. The human-readable string is placed in buf.

Returns

none No returns.

Parameters

e	error code returned by wolfSSL_get_error().
buff	output buffer containing human-readable error string matching e.
len	maximum length in characters which may be written to buf.

Example

int err = 0;
WOLFSSL* ssl;
char buffer[80];
...
err = wolfSSL_get_error(ssl, 0);
wolfSSL_ERR_error_string_n(err, buffer, 80);
printf(“err = %d, %s\n”, err, buffer);

See also

wolfSSL_get_error

wolfSSL_ERR_error_string

wolfSSL_ERR_print_errors_fp

wolfSSL_load_error_strings

wolfSSL_ERR_peek_last_error()

WOLFSSL_API unsigned long wolfSSL_ERR_peek_last_error

(

void

)

This function returns the absolute value of the last error from WOLFSSL_ERROR encountered.

Returns

error Returns absolute value of last error.

Parameters

none	No parameters.

Example

unsigned long err;
...
err = wolfSSL_ERR_peek_last_error();
// inspect err value

See also

wolfSSL_ERR_print_errors_fp

wolfSSL_ERR_print_errors_cb()

WOLFSSL_API void wolfSSL_ERR_print_errors_cb	(	int(*	cb )(const char *str, size_t len, void *u),
		void *	u )

This function uses the provided callback to handle error reporting. The callback function is executed for each error line. The string, length, and userdata are passed into the callback parameters.

Returns

none No returns.

Parameters

cb	the callback function.
u	userdata to pass into the callback function.

Example

int error_cb(const char *str, size_t len, void *u)
{ fprintf((FILE*)u, "%-*.*s\n", (int)len, (int)len, str); return 0; }
...
FILE* fp = ...
wolfSSL_ERR_print_errors_cb(error_cb, fp);

See also

wolfSSL_get_error

wolfSSL_ERR_error_string

wolfSSL_ERR_error_string_n

wolfSSL_load_error_strings

wolfSSL_ERR_print_errors_fp()

WOLFSSL_API void wolfSSL_ERR_print_errors_fp	(	FILE *	,
		int	err )

This function converts an error code returned by wolfSSL_get_error() into a more human-readable error string and prints that string to the output file - fp. err is the error code returned by wolfSSL_get_error() and fp is the file which the error string will be placed in.

Returns

none No returns.

Parameters

fp	output file for human-readable error string to be written to.
err	error code returned by wolfSSL_get_error().

Example

int err = 0;
WOLFSSL* ssl;
FILE* fp = ...
...
err = wolfSSL_get_error(ssl, 0);
wolfSSL_ERR_print_errors_fp(fp, err);

See also

wolfSSL_get_error

wolfSSL_ERR_error_string

wolfSSL_ERR_error_string_n

wolfSSL_load_error_strings

wolfSSL_get_error()

WOLFSSL_API int wolfSSL_get_error	(	WOLFSSL *	ssl,
		int	ret )

This function returns a unique error code describing why the previous API function call (wolfSSL_connect, wolfSSL_accept, wolfSSL_read, wolfSSL_write, etc.) resulted in an error return code (SSL_FAILURE). The return value of the previous function is passed to wolfSSL_get_error through ret. After wolfSSL_get_error is called and returns the unique error code, wolfSSL_ERR_error_string() may be called to get a human-readable error string. See wolfSSL_ERR_error_string() for more information.

Returns

code On successful completion, this function will return the unique error code describing why the previous API function failed.

SSL_ERROR_NONE will be returned if ret > 0.

Parameters

ssl	pointer to the SSL object, created with wolfSSL_new().
ret	return value of the previous function that resulted in an error return code.

Example

int err = 0;
WOLFSSL* ssl;
char buffer[80];
...
err = wolfSSL_get_error(ssl, 0);
wolfSSL_ERR_error_string(err, buffer);
printf(“err = %d, %s\n”, err, buffer);

See also

wolfSSL_ERR_error_string

wolfSSL_ERR_error_string_n

wolfSSL_ERR_print_errors_fp

wolfSSL_load_error_strings

wolfSSL_load_error_strings()

WOLFSSL_API void wolfSSL_load_error_strings

(

void

)

This function is for OpenSSL compatibility (SSL_load_error_string) only and takes no action.

Returns

none No returns.

Parameters

none	No parameters.

Example

wolfSSL_load_error_strings();

See also

wolfSSL_get_error

wolfSSL_ERR_error_string

wolfSSL_ERR_error_string_n

wolfSSL_ERR_print_errors_fp

wolfSSL_load_error_strings

wolfSSL_want_read()

WOLFSSL_API int wolfSSL_want_read

(

WOLFSSL *

ssl

)

This function is similar to calling wolfSSL_get_error() and getting SSL_ERROR_WANT_READ in return. If the underlying error state is SSL_ERROR_WANT_READ, this function will return 1, otherwise, 0.

Returns

1 wolfSSL_get_error() would return SSL_ERROR_WANT_READ, the underlying I/O has data available for reading.

0 There is no SSL_ERROR_WANT_READ error state.

Parameters

ssl	pointer to the SSL session, created with wolfSSL_new().

Example

int ret;
WOLFSSL* ssl = 0;
...
 
ret = wolfSSL_want_read(ssl);
if (ret == 1) {
    // underlying I/O has data available for reading (SSL_ERROR_WANT_READ)
}

See also

wolfSSL_want_write

wolfSSL_get_error

wolfSSL_want_write()

WOLFSSL_API int wolfSSL_want_write

(

WOLFSSL *

ssl

)

This function is similar to calling wolfSSL_get_error() and getting SSL_ERROR_WANT_WRITE in return. If the underlying error state is SSL_ERROR_WANT_WRITE, this function will return 1, otherwise, 0.

Returns

1 wolfSSL_get_error() would return SSL_ERROR_WANT_WRITE, the underlying I/O needs data to be written in order for progress to be made in the underlying SSL connection.

0 There is no SSL_ERROR_WANT_WRITE error state.

Parameters

ssl	pointer to the SSL session, created with wolfSSL_new().

Example

int ret;
WOLFSSL* ssl = 0;
...
ret = wolfSSL_want_write(ssl);
if (ret == 1) {
    // underlying I/O needs data to be written (SSL_ERROR_WANT_WRITE)
}

See also

wolfSSL_want_read

wolfSSL_get_error