Logging

wolfProvider supports output of log messages for informative and debug purposes. To enable debug logging, wolfProvider must first be compiled with debug support enabled. If using Autoconf, this is done using the --enable-debug option to ./configure:

./configure --enable-debug

If not using Autoconf/configure, define WOLFPROVIDER_DEBUG when compiling the wolfProvider library.

Controlling Logging Levels

wolfProvider supports the following logging levels. These are defined in the “include/wolfprovider/wp_logging.h” header file as part of the wolfProvider_LogType enum:

Log Enum	Description	Log Enum Value
WP_LOG_ERROR	Logs errors	0x0001
WP_LOG_ENTER	Logs when entering functions	0x0002
WP_LOG_LEAVE	Logs when leaving functions	0x0004
WP_LOG_INFO	Logs informative messages	0x0008
WP_LOG_VERBOSE	Verbose logs, including encrypted/decrypted/digested data	0x0010
WP_LOG_LEVEL_DEFAULT	Default log level, all except verbose level	WP_LOG_ERROR | WP_LOG_ENTER | WP_LOG_LEAVE | WP_LOG_INFO
WP_LOG_LEVEL_ALL WP_LOG_ERROR	All log levels are enabled	WP_LOG_ENTER | WP_LOG_LEAVE | WP_LOG_INFO | WP_LOG_VERBOSE

The default wolfProvider logging level includes WP_LOG_ERROR, WP_LOG_ENTER, WP_LOG_LEAVE, and WP_LOG_INFO. This includes all log levels except verbose logs (WP_LOG_VERBOSE).

Log levels can be controlled using the wolfProv_SetLogLevel(int mask). For example, to turn on only error and informative logs:

#include <wolfprovider/wp_logging.h>

ret = wolfProv_SetLogLevel(WP_LOG_ERROR | WP_LOG_INFO);
if (ret != 0) {
    printf(“Failed to set logging level\n”);
}

Controlling Component Logging

wolfProvider allows logging on a per-component basis. Components are defined in the wolfProvider_LogComponents enum in include/wolfprovider/wp_logging.h:

Log Component Enum	Description	Component Enum Value
WP_LOG_RNG	Random number generation	0x0001
WP_LOG_DIGEST	Digests (SHA-1/2/3)	0x0002
WP_LOG_MAC	MAC functions (HMAC, CMAC)	0x0004
WP_LOG_CIPHER	Ciphers (AES, 3DES)	0x0008
WP_LOG_PK	Public Key Algorithms (RSA, ECC)	0x0010
WP_LOG_KE	Key Agreement Algorithms (DH, ECDH)	0x0020
WP_LOG_PROVIDER	All provider specific logs	0x0040
WP_LOG_COMPONENTS_ALL	Log all components	WP_LOG_RNG | WP_LOG_DIGEST | WP_LOG_MAC | WP_LOG_CIPHER | WP_LOG_PK | WP_LOG_KE | WP_LOG_PROVIDER
WP_LOG_COMPONENTS_DEFAULT	Default components logged (all).	WP_LOG_COMPONENTS_ALL

The default wolfProvider logging configuration logs all components (WP_LOG_COMPONENTS_DEFAULT).

Components logged can be controlled using the wolfProv_SetLogComponents(int mask). For example, to turn on only logging only for the Digest and Cipher algorithms:

#include <wolfprovider/wp_logging.h>

ret = wolfProv_SetLogComponents(WP_LOG_DIGEST | WP_LOG_CIPHER);
if (ret != 0) {
    printf(“Failed to set log components\n”);
}

Setting a Custom Logging Callback

By default wolfProvider outputs debug log messages using fprintf() to stderr.

Applications that want to have more control over how or where log messages are output can write and register a custom logging callback with wolfProvider. The logging callback should match the prototype of wolfProvider_Logging_cb in include/wolfprovider/wp_logging.h:

/**
* wolfProvider logging callback.
* logLevel - [IN] - Log level of message
* component - [IN] - Component that log message is coming from
* logMessage - [IN] - Log message
*/
typedef void (* **wolfProvider_Logging_cb** )(const int logLevel,
const int component,
const char *const logMessage);

The callback can then be registered with wolfProvider using the wolfProv_SetLoggingCb(wolfProv_Logging_cb logf). For example:

void **customLogCallback** (const int logLevel, const int component,
const char* const logMessage)
{
    (void)logLevel;
    (void)component;
    fprintf(stderr, “wolfProvider log message: %d\n”, logMessage);
}

int **main** (void)
{
    int ret;
...
    ret = wolfProv_SetLoggingCb((void(*)(void))my_Logging_cb);
    if (ret != 0) {
        /* failed to set logging callback */
    }
...
}