janus: +default sanitizer options

mom-informative stack unwind if leak detected in so-module

====================================================================================== default:
Indirect leak of 128 byte(s) in 1 object(s) allocated from:
    #0 0x7f36052b0b50 in __interceptor_malloc (/usr/lib/x86_64-linux-gnu/libasan.so.4+0xdeb50)
    meetecho#1 0x7f3603af545c  (/usr/lib/x86_64-linux-gnu/libjansson.so.4+0x345c)
    meetecho#2 0x7f3602808b96 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x21b96)
Indirect leak of 72 byte(s) in 1 object(s) allocated from:
    #0 0x7f36052b0b50 in __interceptor_malloc (/usr/lib/x86_64-linux-gnu/libasan.so.4+0xdeb50)
    meetecho#1 0x7f3603afa61a in json_object (/usr/lib/x86_64-linux-gnu/libjansson.so.4+0x861a)
    meetecho#2 0x7f3602808b96 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x21b96)
SUMMARY: AddressSanitizer: 200 byte(s) leaked in 2 allocation(s).

====================================================================================== no_fast_unwind:
Indirect leak of 128 byte(s) in 1 object(s) allocated from:
    #0 0x7f3554f8fb50 in __interceptor_malloc (/usr/lib/x86_64-linux-gnu/libasan.so.4+0xdeb50)
    meetecho#1 0x7f35537d445c  (/usr/lib/x86_64-linux-gnu/libjansson.so.4+0x345c)
    meetecho#2 0x7f35537d9646 in json_object (/usr/lib/x86_64-linux-gnu/libjansson.so.4+0x8646)
    meetecho#3 0x55928c01143a in main /home/dima/work/janus.github/src/janus.c:3269
    meetecho#4 0x7f35524e7b96 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x21b96)
    meetecho#5 0x55928bfc74c9 in _start (/home/dima/work/janus.github/cmake-gcc/janus+0x1364c9)
Indirect leak of 72 byte(s) in 1 object(s) allocated from:
    #0 0x7f3554f8fb50 in __interceptor_malloc (/usr/lib/x86_64-linux-gnu/libasan.so.4+0xdeb50)
    meetecho#1 0x7f35537d961a in json_object (/usr/lib/x86_64-linux-gnu/libjansson.so.4+0x861a)
    meetecho#2 0x55928c01143a in main /home/dima/work/janus.github/src/janus.c:3269
    meetecho#3 0x7f35524e7b96 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x21b96)
    meetecho#4 0x55928bfc74c9 in _start (/home/dima/work/janus.github/cmake-gcc/janus+0x1364c9)
SUMMARY: AddressSanitizer: 200 byte(s) leaked in 2 allocation(s).

src/janus.c

@@ -3247,6 +3247,14 @@ static gboolean install_transport(janus_transport *janus_transport)
     return TRUE;
 }
 
+#if __SANITIZE_ADDRESS__
+/* disable fast_unwind to enable correct stack view if reported memory was allocated in *.so module */
+const char *__asan_default_options(void);
+const char *__asan_default_options(void) {
+	return "symbolize=1:fast_unwind_on_malloc=0";
+}
+#endif
+
 /* Main */
 gint main(int argc, char *argv[])
 {