introduce moveto3

A program to move a file descriptor to 3 required for qmail-authuser and does not require a shell

1 files changed, 29 insertions, 0 deletions

diff --git a/script/moveto3.py b/script/moveto3.py
new file mode 100755
index 0000000..ae10d63
--- /dev/null
+++ b/script/moveto3.py
@@ -0,0 +1,29 @@
+#!/usr/bin/env python
+import argparse
+import os
+import sys
+
+
+def main():
+    ap = argparse.ArgumentParser()
+    ap.add_argument("-a", default="qmail-authuser", dest="pam")
+    ap.add_argument("fd", type=int)
+    ap.add_argument("prog")
+    ap.add_argument("args", nargs='*')
+
+    vals = ap.parse_args()
+
+    if vals.fd < 3:
+        raise ValueError(f"fd({fd}) must be 3 or greater")
+
+    if vals.fd != 3:
+        os.dup2(vals.fd, 3)
+        os.close(vals.fd)
+
+    os.execvp(vals.pam, [vals.pam, vals.prog] + vals.args)
+
+    raise ValueError("should not be reachable")
+
+
+if __name__ == '__main__':
+    main()