From: Pierre-Marc Fournier <pierre-marc.fournier@polymtl.ca>
Date: Tue, 17 Feb 2009 20:12:20 +0000 (-0500)
Subject: ust: allow tracing of dynamically linked libraries
X-Git-Tag: v0.1~289
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=c463904d75d0711fe6380ef0cda4ed07e6f7f969;p=ust.git

ust: allow tracing of dynamically linked libraries

- this also includes being able to link libmarkers dynamically
- a special init function must be added via the MARKER_LIB macro
---

diff --git a/hello/Makefile b/hello/Makefile
index eeb43fd..57cc8f2 100644
--- a/hello/Makefile
+++ b/hello/Makefile
@@ -2,9 +2,9 @@ all: hello
 
 hello: hello.c
 #dynamic version
-#	gcc -g -I../libmarkers -I../share -I../libtracing -L../libmarkers -lmarkers -L../libtracectl -ltracectl -L../libtracing -ltracing -o hello hello.c marker-control.c serialize.c -static
+	gcc -g -Wl,--print-map -I../libmarkers -I../share -I../libtracing -L../libmarkers -lmarkers -L../libtracectl -ltracectl -L../libtracing -ltracing -o hello hello.c marker-control.c serialize.c
 #static version
-	gcc -g -I../libmarkers -I../share -I../libtracing -L../libmarkers -o hello hello.c marker-control.c serialize.c ../libtracing/*.c ../libmarkers/*.c ../libtracectl/*.c ../share/*.c
+#	gcc -g -I../libmarkers -I../share -I../libtracing -L../libmarkers -o hello hello.c marker-control.c serialize.c ../libtracing/*.c ../libmarkers/*.c ../libtracectl/*.c ../share/*.c
 
 clean:
 	rm -rf hello *.o
diff --git a/hello/hello.c b/hello/hello.c
index d6750d0..ee7992b 100644
--- a/hello/hello.c
+++ b/hello/hello.c
@@ -204,6 +204,11 @@ int main()
 
 	printf("page size is %d\n", sysconf(_SC_PAGE_SIZE));
 
+//	extern struct marker __start___markers[] __attribute__((visibility("hidden")));
+//	extern struct marker __stop___markers[] __attribute__((visibility("hidden")));
+//
+//	printf("the executable's markers start at %lx and end at %lx, the size of a marker is %d\n", __start___markers, __stop___markers, sizeof(struct marker));
+
 	marker_control_init();
 
 	//marker_probe_register("abc", "testmark", "", probe, NULL);
@@ -268,3 +273,5 @@ int main()
 
 	return 0;
 }
+
+MARKER_LIB
diff --git a/libmarkers/marker.c b/libmarkers/marker.c
index d31f2cf..139b432 100644
--- a/libmarkers/marker.c
+++ b/libmarkers/marker.c
@@ -37,8 +37,8 @@
 #include "tracercore.h"
 #include "tracer.h"
 
-extern struct marker __start___markers[];
-extern struct marker __stop___markers[];
+extern struct marker __start___markers[] __attribute__((visibility("hidden")));
+extern struct marker __stop___markers[] __attribute__((visibility("hidden")));
 
 /* Set to 1 to enable marker debug output */
 static const int marker_debug;
@@ -705,9 +705,10 @@ void marker_update_probe_range(struct marker *begin,
 static void marker_update_probes(void)
 {
 	/* Core kernel markers */
-	marker_update_probe_range(__start___markers, __stop___markers);
+//ust//	marker_update_probe_range(__start___markers, __stop___markers);
 	/* Markers in modules. */
 //ust//	module_update_markers();
+	lib_update_markers();
 //ust//	tracepoint_probe_update_all();
 	/* Update immediate values */
 	core_imv_update();
@@ -1062,6 +1063,7 @@ static void marker_get_iter(struct marker_iter *iter)
 
 	/* Core kernel markers */
 	if (!iter->lib) {
+		/* ust FIXME: how come we cannot disable the following line? we shouldn't need core stuff */
 		found = marker_get_iter_range(&iter->marker,
 				__start___markers, __stop___markers);
 		if (found)
@@ -1443,6 +1445,17 @@ int lib_get_iter_markers(struct marker_iter *iter)
 	return found;
 }
 
+void lib_update_markers(void)
+{
+	struct lib *lib;
+
+//ust//	mutex_lock(&module_mutex);
+	list_for_each_entry(lib, &libs, list)
+		marker_update_probe_range(lib->markers_start,
+				lib->markers_start + lib->markers_count);
+//ust//	mutex_unlock(&module_mutex);
+}
+
 int marker_register_lib(struct marker *markers_start, int markers_count)
 {
 	struct lib *pl;
@@ -1458,3 +1471,9 @@ int marker_register_lib(struct marker *markers_start, int markers_count)
 	
 	return 0;
 }
+
+static void __attribute__((constructor)) __markers__init(void)
+{
+	marker_register_lib(__start___markers, (((long)__stop___markers)-((long)__start___markers))/sizeof(struct marker));
+	printf("markers_start: %p, markers_stop: %p\n", __start___markers, __stop___markers);
+}
diff --git a/libmarkers/marker.h b/libmarkers/marker.h
index f26bcac..b83ff65 100644
--- a/libmarkers/marker.h
+++ b/libmarkers/marker.h
@@ -282,5 +282,15 @@ struct lib {
 	struct list_head list;
 };
 
+int marker_register_lib(struct marker *markers_start, int markers_count);
+
+#define MARKER_LIB						\
+extern struct marker __start___markers[] __attribute__((visibility("hidden")));			\
+extern struct marker __stop___markers[] __attribute__((visibility("hidden")));				\
+								\
+static void __attribute__((constructor)) __markers__init(void) 	\
+{								\
+	marker_register_lib(__start___markers, (((long)__stop___markers)-((long)__start___markers))/sizeof(struct marker));\
+}
 
 #endif