xlib integrated debugging (Tracing) - gdb

Question

Is there any debugging options built-in in the Xlib (libX11.so)? Can I get list of X11 lib calls?
I want to get full trace of xlib function calls from heavy-multithreaded, closed-source program. It is one not-public embedded platform, so I can't use gdb for multithreaded debugging and there is no ltrace on the platform.
Also, this program can't connect to x server over tcp/ip, only unix-socket. I want to do tracing of xlib calls from xlib itself.
ps. Xlib from rather modern xfree or even xorg. from gnu linux

Answer 1

You may be able to use xscope to monitor the requests sent over a Unix socket, even when you can't send the X protocol over TCP to be able to use network monitoring tools like Wireshark.

Answer 2

You might look into xlibtrace, which traces at the interface between Xlib and your code, rather than the X Windows wire protocol. I've executed a couple of the examples, and it seems to work.
The source is available at http://kev.pulo.com.au/xlibtrace
I had to modify it to get it to compile:
diff -u src/libxlibtrace-functions.h.sh.orig src/libxlibtrace-functions.h.sh
--- src/libxlibtrace-functions.h.sh.orig 2009-01-19 23:43:46.000000000 -0500
+++ src/libxlibtrace-functions.h.sh 2016-02-24 13:49:25.155556294 -0500
## -81,7 +81,7 ##
return (t ~ /^[cC][oO][nN][sS][tT][ ]/);
}
-function isarray(t) {
+function our_isarray(t) {
return (t ~ /\[.*\]$/);
}
## -90,7 +90,7 ##
return sprintf("%s", t);
} else if (isfunctionpointer(t)) {
return gensub("^(.*\\(\\*)(\\).*)$", "\\1"n"\\2", "", t);
- } else if (isarray(t)) {
+ } else if (our_isarray(t)) {
return gensub("^(.*)(\\[.*\\])$", "\\1"n"\\2", "", t);
} else {
return sprintf("%s %s", t, n);
diff -u src/libxlibtrace-print-x.h.orig src/libxlibtrace-print-x.h
--- src/libxlibtrace-print-x.h.orig 2009-01-19 22:30:06.000000000 -0500
+++ src/libxlibtrace-print-x.h 2016-02-24 14:27:08.681352710 -0500
## -2415,6 +2415,20 ##
dofflush(f);
})
+// XGenericEventCookie
+#define __REALTYPE_XGenericEventCookie__ XGenericEventCookie
+#define __REALTYPE_XGenericEventCookie_p__ XGenericEventCookie *
+#define __REALTYPE_XGenericEventCookie_pp__ XGenericEventCookie **
+#define __TRACE_PRINT_TYPE_STRUCT_BODY_XGenericEventCookie__(safetype) \
+ __TRACE_PRINT_STRUCT_MEMBER__(f, safetype, *value, int, type) __PRINT_COMMA__(f) \
+ __TRACE_PRINT_STRUCT_MEMBER__(f, safetype, *value, unsigned_long, serial) __PRINT_COMMA__(f) \
+ __TRACE_PRINT_STRUCT_MEMBER__(f, safetype, *value, Bool, send_event) __PRINT_COMMA__(f) \
+ __TRACE_PRINT_STRUCT_MEMBER__(f, safetype, *value, Display_p, display) __PRINT_COMMA__(f) \
+ __TRACE_PRINT_STRUCT_MEMBER__(f, safetype, *value, int, extension) __PRINT_COMMA__(f) \
+ __TRACE_PRINT_STRUCT_MEMBER__(f, safetype, *value, int, evtype) __PRINT_COMMA__(f) \
+ __TRACE_PRINT_STRUCT_MEMBER__(f, safetype, *value, unsigned_int, cookie) __PRINT_COMMA__(f) \
+ __TRACE_PRINT_STRUCT_MEMBER__(f, safetype, *value, void_p, data)
+__INDIRECT_CALL_3__(__TRACE_PRINT_TYPE_STRUCT,__LIBXLIBTRACE_PRINT_X_SUFF__,__)(XGenericEventCookie)
#undef __LIBXLIBTRACE_PRINT_X_BODY__