add :SETUID connection type

Signed-off-by: Sean Whitton <spwhitton@spwhitton.name>

1 files changed, 40 insertions, 0 deletions

diff --git a/src/connection/setuid.lisp b/src/connection/setuid.lisp
new file mode 100644
index 0000000..4ca12fc
--- /dev/null
+++ b/src/connection/setuid.lisp
@@ -0,0 +1,40 @@
+;;; Consfigurator -- Lisp declarative configuration management system
+
+;;; Copyright (C) 2021  Sean Whitton <spwhitton@spwhitton.name>
+
+;;; This file is free software; you can redistribute it and/or modify
+;;; it under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3, or (at your option)
+;;; any later version.
+
+;;; This file is distributed in the hope that it will be useful,
+;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU General Public License for more details.
+
+;;; You should have received a copy of the GNU General Public License
+;;; along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+(in-package :consfigurator.connection.setuid)
+(named-readtables:in-readtable :consfigurator)
+#+sbcl (eval-when (:compile-toplevel :load-toplevel :execute)
+         (require "sb-posix"))
+
+(defun setuid (uid)
+  #+sbcl      (sb-posix:setuid uid)
+  #-(or sbcl) (foreign-funcall "setuid" :unsigned-int uid :int))
+
+(defun setgid (gid)
+  #+sbcl      (sb-posix:setgid gid)
+  #-(or sbcl) (foreign-funcall "setgid" :unsigned-int uid :int))
+
+(defmethod establish-connection ((type (eql :setuid)) remaining &key to)
+  (informat 1 "~&SETUIDing to ~A" to)
+  (re:register-groups-bind ((#'parse-integer uid gid))
+      (#?/uid=([0-9]+).+gid=([0-9]+)/ (mrun "id" to))
+    (with-fork-connection (remaining)
+      (unless (zerop (setgid gid))
+        (error "setgid(2) failed; are you root?"))
+      (unless (zerop (setuid uid))
+        (error "setuid(2) failed; are you root?"))
+      (uiop:chdir (user:passwd-entry 5 uid)))))