app_python: fixing clone string for dirname and basename

- variable tname replaced by dname_src and bname_src, because both
  dirname() and basename() requires it's argument not to change: "These
  functions may return pointers to statically allocated memory which may
  be overwritten by subsequent calls. Alternatively, they may return a
  pointer to some part of path, so that the string referred to by path
  should not be modified or freed until the pointer returned by the
  function is no longer required."
- related to FS#137

Signed-off-by: Daniel-Constantin Mierla <[email protected]>

modules/app_python/python_mod.c

@@ -85,7 +85,7 @@ struct module_exports exports = {
 static int
 mod_init(void)
 {
-    char *dname, *bname, *tname;
+    char *dname, *bname, *dname_src, *bname_src;
     int i;
     PyObject *sys_path, *pDir, *pModule, *pFunc, *pArgs;
     PyThreadState *mainThreadState;
@@ -100,19 +100,19 @@ mod_init(void)
         child_init_mname.len = strlen(child_init_mname.s);
     }
 
-    tname = as_asciiz(&script_name);
-	if(tname==NULL)
-	{
-		LM_ERR("no more pkg memory\n");
-		return -1;
-	}
-    dname = dirname(tname);
+    dname_src = as_asciiz(&script_name);
+    bname_src = as_asciiz(&script_name);
+    if(dname_src==NULL || bname_src==NULL)
+    {
+            LM_ERR("no more pkg memory\n");
+            return -1;
+    }
+
+    dname = dirname(dname_src);
     if (strlen(dname) == 0)
         dname = ".";
-	memcpy(tname, script_name.s, script_name.len);
-    bname = basename(tname);
+    bname = basename(bname_src);
     i = strlen(bname);
-	pkg_free(tname);
     if (bname[i - 1] == 'c' || bname[i - 1] == 'o')
         i -= 1;
     if (bname[i - 3] == '.' && bname[i - 2] == 'p' && bname[i - 1] == 'y') {
@@ -159,6 +159,9 @@ mod_init(void)
         return -1;
     }
 
+    pkg_free(dname_src);
+    pkg_free(bname_src);
+
     pFunc = PyObject_GetAttrString(pModule, mod_init_fname.s);
     Py_DECREF(pModule);
     /* pFunc is a new reference */