add function to prefix cmd with abspath using whereis

src/util.py

 import os
+import subprocess
 import sys
 
 import src.globalvars
@@ -23,6 +24,23 @@ def find_cmd(cmd):
 
     return None
 
+def prefix_cmd_with_abspath(cmd):
+    """Prefix cmd with the abspath of the first word
+
+    Usefull if cmd should be executed by the loader of a custom glibc."""
+
+    binary_end = cmd.find(" ")
+    binary_end = None if binary_end == -1 else binary_end
+
+    cmd_start = len(cmd) if binary_end == None else binary_end
+
+    binary_abspath = subprocess.run(["whereis", cmd[0:binary_end]],
+                                    stdout=subprocess.PIPE,
+                                    universal_newlines=True).stdout.split()[1]
+
+    return binary_abspath + " " + cmd[binary_end:]
+
+
 def allocbench_msg(color, *objects, sep=' ', end='\n', file=sys.stdout):
     if src.globalvars.verbosity < 0:
         return