add event hooks

bin/hooks/reject-extension.py

@@ -0,0 +1,30 @@
+#!/usr/bin/env python3
+
+import sys
+
+
+_ = r"""
+reject file uploads by file extension
+
+example usage as global config:
+    --xbu c,bin/hooks/reject-extension.py
+
+example usage as a volflag (per-volume config):
+    -v srv/inc:inc:c,xbu=c,bin/hooks/reject-extension.py
+
+parameters explained,
+    xbu = execute before upload
+    c   = check result, reject upload if error
+"""
+
+
+def main():
+    bad = "exe scr com pif bat ps1 jar msi"
+
+    ext = sys.argv[1].split(".")[-1]
+
+    sys.exit(1 if ext in bad.split() else 0)
+
+
+if __name__ == "__main__":
+    main()