Support mapping a process instead of a binary.

README.md

@@ -9,6 +9,13 @@ dot -Tsvg -o out.svg out.dot
 eog out.svg
 ```
 
+## Alternate Usage
+
+It is also possible to map the actually loaded .so files of a process by giving the tool a PID instead of a file.
+```
+./sotrace.py PID out.dot
+```
+
 ![example output](images/out-glxgears.svg "glxgears dependencies")
 
 ## Rationale

sotrace.py

@@ -43,28 +43,65 @@ def dep_to_lib(tgt, deps) :
 
 
 # Walk the dependencies of the target, and write the graph to file.
-def traverse_so(tgt, nam, f, depth, visited, linked) :
+def traverse_so(tgt, nam, f, depth, visited, linked, keep_suffix) :
+	visited.add(tgt)
 	deps = dep_list(tgt)
 	lib_map = dep_to_lib(tgt, deps)
 
 	for val in lib_map.keys() :
-		if nam != val and (nam,val) not in linked:
-			linked.append( (nam,val) )
-			f.write('"' + nam + '" -> "' + val + '"\n')
+		link = (nam, val) if keep_suffix else (nam.split('.so')[0], val.split('.so')[0])
+		linked.add(link)
 
 	for dep in deps:
 		if dep in lib_map:
 			m = lib_map[dep]
 			if not m in visited:
-				visited.append(m)
+				visited.add(m)
 				dnam = os.path.basename(dep)
-				traverse_so(m, dnam, f, depth+1, visited, linked)
+				traverse_so(m, dnam, f, depth+1, visited, linked, keep_suffix)
+
+
+# Walk the deps, starting from the mapped files of a process.
+def trace_pid(tgt, f, visited, linked, keep_suffix) :
+	nf = open("/proc/%s/comm" % (tgt,), "r")
+	nam = nf.readline().strip()
+	nf.close()
+	cmd = "ls -l /proc/%s/map_files" % (tgt,)
+	cf = os.popen(cmd, "r")
+	lines = [ x.split(" -> ")[1].strip() for x in cf.readlines() if " -> " in x and ".so" in x ]
+	cf.close()
+	libs = sorted(set(lines))
+	print("Tracing shared objects from command", nam, "with", len(lines), "mapped .so files.")
+	lib_map = {}
+
+	depth = 0
+
+	for lib in libs:
+		libname = os.path.basename(lib)
+		lib_map[libname] = lib
+
+	for val in lib_map.keys() :
+		if keep_suffix :
+			link = (nam, val)
+			linked.add(link)
+		else :
+			link = (nam.split('.so')[0], val.split('.so')[0])
+			linked.add(link)
+
+	for dep in lib_map.keys() :
+		if dep in lib_map :
+			m = lib_map[dep]
+			if not m in visited :
+				visited.add(m)
+				dnam = os.path.basename(dep)
+				traverse_so(m, dnam, f, depth+1, visited, linked, keep_suffix)
 
 # Main entry point
 if __name__ == '__main__' :
 
 	if len(sys.argv) != 3 :
-		print("Usage:", sys.argv[0], "libfoo.so graph.dot")
+		print("Usage:    ", sys.argv[0], "libfoo.so out.dot")
+		print("Alt Usage:", sys.argv[0], "<PID> out.dot")
 		sys.exit(1)
 
 	tgt = sys.argv[1]
@@ -74,7 +111,20 @@ def traverse_so(tgt, nam, f, depth, visited, linked) :
 	f = open(out, "w")
 	f.write("digraph G {\n")
 	f.write("  rankdir = LR;\n")
-	traverse_so(tgt, nam, f, 0, [], [])
+
+	linked = set()
+	visited = set()
+
+	if tgt.isnumeric() :
+		keep_suffix = False
+		trace_pid(tgt, f, visited, linked, keep_suffix)
+	else :
+		keep_suffix = True
+		traverse_so(tgt, nam, f, 0, visited, linked, keep_suffix)
+
+	for link in linked :
+		f.write('"' + link[0] + '" -> "' + link[1] + '"\n')
+
 	f.write("}\n");
 	f.close()