[BUILD] add option to build the dnbd3-server with afl-fuzz support

The afl-fuzz support for the dnbd3-server requires an AFL C compiler
like afl-gcc and can be enabled with the CMake option DNBD3_SERVER_AFL.

5 files changed, 55 insertions, 16 deletions

diff --git a/src/bench/main.c b/src/bench/main.c
index a167f05..1a59747 100644
--- a/src/bench/main.c
+++ b/src/bench/main.c
@@ -76,6 +76,8 @@ int main(int argc, char *argv[])
 	int n_threads = 1;
 	int bs = 4096;
 
+	log_init();
+
 	if ( argc <= 1 || strcmp( argv[1], "--help" ) == 0 || strcmp( argv[1], "--usage" ) == 0 ) {
 		printUsage( argv[0], 0 );
 	}
diff --git a/src/fuse/main.c b/src/fuse/main.c
index 5cf3e81..2a851a7 100644
--- a/src/fuse/main.c
+++ b/src/fuse/main.c
@@ -329,6 +329,8 @@ int main( int argc, char *argv[] )
 	char *mountpoint;
 	int foreground = 0;
 
+	log_init();
+
 	if ( argc <= 1 || strcmp( argv[1], "--help" ) == 0 || strcmp( argv[1], "--usage" ) == 0 ) {
 		printUsage( argv[0], 0 );
 	}
diff --git a/src/server/CMakeLists.txt b/src/server/CMakeLists.txt
index 1855d91..aa981f6 100644
--- a/src/server/CMakeLists.txt
+++ b/src/server/CMakeLists.txt
@@ -13,9 +13,27 @@ endif(NOT JANSSON_FOUND)
 add_definitions(-D_GNU_SOURCE)
 
 if(DNBD3_SERVER_AFL)
+    # check if DNBD3_RELEASE_HARDEN is disabled
+    if(DNBD3_RELEASE_HARDEN)
+        message(FATAL_ERROR "DNBD3_SERVER_AFL can only be enabled if DNBD3_RELEASE_HARDEN is disabled")
+    endif(DNBD3_RELEASE_HARDEN)
+
     # build dnbd3-server with AFL support
     message(STATUS "Building dnbd3-server with AFL support")
     add_definitions(-DDNBD3_SERVER_AFL)
+
+    # change compiler for dnbd3-server sources if AFL enabled
+    include(CheckAFLCCompiler)
+    check_afl_c_compiler(AFL_C_COMPILER AFL_C_COMPILER_NAME ${CMAKE_C_COMPILER} ${CMAKE_C_COMPILER_ID})
+    if(AFL_C_COMPILER)
+        message(STATUS "Check for working AFL C compiler: ${AFL_C_COMPILER} - done")
+        # change C compiler to a corresponding AFL C compiler
+        set(CMAKE_C_COMPILER "${AFL_C_COMPILER}")
+    else(AFL_C_COMPILER)
+        # no corresponding AFL C compiler found
+        message(STATUS "Check for working AFL C compiler: ${AFL_C_COMPILER_NAME} - failed")
+        message(FATAL_ERROR "No corresponding AFL C compiler ${AFL_C_COMPILER_NAME} was found for the C compiler ${CMAKE_C_COMPILER}!")
+    endif(AFL_C_COMPILER)
 endif(DNBD3_SERVER_AFL)
 
 add_executable(dnbd3-server ${CMAKE_CURRENT_SOURCE_DIR}/altservers.c
diff --git a/src/server/server.c b/src/server/server.c
index 55ec042..0ee51c4 100644
--- a/src/server/server.c
+++ b/src/server/server.c
@@ -217,6 +217,16 @@ int main(int argc, char *argv[])
 			{ 0, 0, 0, 0 }
 	};
 
+	log_init();
+
+	/* set proper output stream for AFL */
+#ifdef DNBD3_SERVER_AFL
+	if ( log_setConsoleOutputStream(stderr) < 0 ) {
+		logadd( LOG_ERROR, "Failed to set output stream for AFL to stderr" );
+		exit( EXIT_FAILURE );
+	}
+#endif
+
 	mainPid = getpid();
 	mainThread = pthread_self();
 	opt = getopt_long( argc, argv, optString, longOpts, &longIndex );
@@ -278,6 +288,7 @@ int main(int argc, char *argv[])
 		opt = getopt_long( argc, argv, optString, longOpts, &longIndex );
 	}
 
+
 	// Load general config
 
 	if ( _configDir == NULL ) _configDir = strdup( "/etc/dnbd3-server" );
@@ -291,8 +302,6 @@ int main(int argc, char *argv[])
 	timing_get( &startupTime );
 
 #ifdef DNBD3_SERVER_AFL
-	// ###### AFL
-	//
 	image_serverStartup();
 	net_init();
 	uplink_globalsInit();
@@ -316,9 +325,7 @@ int main(int argc, char *argv[])
 		net_handleNewConnection( dnbd3_client );
 		exit( 0 );
 	}
-	//
-	// ###### AFL END
-#endif
+#endif  /* DNBD3_SERVER_AFL */
 
 
 	// One-shots first:
diff --git a/src/shared/log.c b/src/shared/log.c
index f2cab85..374bed1 100644
--- a/src/shared/log.c
+++ b/src/shared/log.c
@@ -36,6 +36,7 @@ static _Atomic logmask_t maskCon  = 15;
 
 static char *logFile = NULL;
 static int logFd = -1;
+static FILE *logOutStream;
 
 static bool consoleTimestamps = false;
 
@@ -43,6 +44,10 @@ static bool consoleTimestamps = false;
 static int writeLevel(char *buffer, logmask_t level);
 
 
+void log_init(void) {
+	logOutStream = stdout;
+}
+
 bool log_hasMask(const logmask_t mask)
 {
 	return ( ( maskFile | maskCon ) & mask ) == mask;
@@ -63,6 +68,15 @@ void log_setConsoleTimestamps(bool on)
 	consoleTimestamps = on;
 }
 
+int log_setConsoleOutputStream(FILE *outputStream)
+{
+	if ( outputStream != stdout && outputStream != stderr )
+		return -EINVAL;
+
+	logOutStream = outputStream;
+	return 0;
+}
+
 bool log_openLogFile(const char *path)
 {
 	pthread_mutex_lock( &logLock );
@@ -93,10 +107,10 @@ void logadd(const logmask_t mask, const char *fmt, ...)
 	struct tm timeinfo;
 	char buffer[LINE_LEN];
 	bool toFile = maskFile & mask;
-	bool toStdout = maskCon & mask;
+	bool toOutStream = maskCon & mask;
 	size_t offset;
 
-	if ( toFile || ( toStdout && consoleTimestamps ) ) {
+	if ( toFile || ( toOutStream && consoleTimestamps ) ) {
 		time( &rawtime );
 		localtime_r( &rawtime, &timeinfo );
 		offset = strftime( buffer, LINE_LEN, "[%d.%m. %H:%M:%S] ", &timeinfo );
@@ -134,15 +148,11 @@ void logadd(const logmask_t mask, const char *fmt, ...)
 		}
 		pthread_mutex_unlock( &logLock );
 	}
-	if ( toStdout ) {
-		if ( consoleTimestamps ) stdoutLine = buffer;
-#ifdef DNBD3_SERVER_AFL
-		fputs( stdoutLine, stderr );
-		fflush( stderr );
-#else
-		fputs( stdoutLine, stdout );
-		fflush( stdout );
-#endif
+	if ( toOutStream ) {
+		if ( consoleTimestamps )
+			stdoutLine = buffer;
+		fputs( stdoutLine, logOutStream );
+		fflush( logOutStream );
 	}
 }