Use run-parts to run a selection of different guards.

[code/molly-guard.git] / checks.d / molly-guard

diff --git a/checks.d/molly-guard b/checks.d/molly-guard
new file mode 100755 (executable)
index 0000000..a9a2e90
--- /dev/null
+++ b/checks.d/molly-guard
@@ -0,0 +1,61 @@
+#!/bin/sh
+#
+# molly-guard -- wrapper script to prevent erroneous shutdowns via SSH
+#
+# Copyright © martin f. krafft <madduck@madduck.net>
+# Released under the terms of the Artistic Licence 2.0
+#
+set -eu
+
+ME=molly-guard
+
+PRETEND_SSH=0
+CMD=$1
+shift
+for arg in "$@"; do
+  case "$arg" in
+    (*-help)
+      usage 2>&1
+      eval $EXEC --help 2>&1
+      exit 1
+      ;;
+    (*-pretend-ssh) PRETEND_SSH=1;;
+  esac
+done
+
+# require an interactive terminal connected to stdin
+test -t 0                    || exit 0
+
+# only run if we are being called over SSH, that is if the current terminal
+# was created by sshd.
+PTS=$(readlink /proc/$$/fd/0)
+if ! pgrep -f "^sshd.+${PTS#/dev/}[[:space:]]*$" >/dev/null \
+  && [ -z "${SSH_CONNECTION:-}" ]; then
+    if [ $PRETEND_SSH -eq 1 ]; then
+      echo "I: this is not an SSH session, but --pretend-ssh was given..."
+    else
+      exit 0
+    fi
+else
+  echo "W: $ME: SSH session detected!"
+fi
+
+
+HOSTNAME="$(hostname --short)"
+
+sigh()
+{
+  echo "Good thing I asked; I won't $CMD $HOSTNAME ..."
+  exit 1
+}
+
+trap 'echo;sigh' 1 2 3 9 10 12 15
+
+echo -n "Please type in hostname of the machine to $CMD: "
+read HOSTNAME_USER || :
+
+[ "$HOSTNAME_USER" = "$HOSTNAME" ] || sigh
+
+trap - 1 2 3 9 10 12 15
+
+exit 0