staticx: Add which_exec()

staticx/utils.py

@@ -45,6 +45,15 @@ def copy_fileobj_to_tempfile(fsrc, **kwargs):
     fdst.seek(0)
     return fdst
 
+
+def which_exec(name, env=None):
+    for path in os.get_exec_path(env=env):
+        xp = os.path.join(path, name)
+        if os.access(xp, os.X_OK):
+            return xp
+    return None
+
+
 def is_iterable(x):
     """Returns true if x is iterable but not a string"""
     return isinstance(x, Iterable) and not isinstance(x, str)

unittest/test_utils.py

@@ -1,6 +1,7 @@
 import tempfile
 import os
 import pytest
+import subprocess
 
 from staticx import utils
 
@@ -63,3 +64,14 @@ def test_single_empty_default():
 
 def test_single_key_none_default():
     assert utils.single([1, 2, 3], key=lambda x: x<0, default='ok') == 'ok'
+
+# which_exec
+def test_which_exec_common():
+    def ext_which(name):
+        return subprocess.check_output(['which', name]).decode().strip()
+
+    for name in ('true', 'date', 'bash', 'python3'):
+        assert ext_which(name) == utils.which_exec(name)
+
+def test_which_exec_bogus():
+    assert utils.which_exec('zZzZzZzZzZzZzZz') == None