Add a check which possibly prints out a warning message.

[code/molly-guard.git] / shutdown

diff --git a/shutdown b/shutdown
index 0a6efd6011e590fea9ef6e80dc6ae0c2ce48fe37..c8005adc3c5b1984dfa8d2878d5d285246abcba7 100755 (executable)
--- a/shutdown
+++ b/shutdown
@@ -9,31 +9,108 @@
 #
 set -eu
 
+ME=molly-guard
+
 CMD="${0##*/}"
 EXEC="/sbin/$CMD"
+
 case "$CMD" in
-  halt|reboot|shutdown)
+  halt|reboot|shutdown|poweroff)
+    if [ ! -f $EXEC ]; then
+      echo "E: $ME: not a regular file: $EXEC" >&2
+      exit 4
+    fi
     if [ ! -x $EXEC ]; then
-      echo "E: not an executable: $EXEC" >&2
+      echo "E: $ME: not an executable: $EXEC" >&2
       exit 3
     fi
     ;;
   *)
-    echo "E: unsupported command: $CMD" >&2
+    echo "E: $ME: unsupported command: $CMD" >&2
     exit 1
     ;;
 esac
 
-if [ -n "${SSH_CONNECTION:-}" ] && test -t 0 && [ "${1:-}" != '--help' ]; then
-  echo -n "SSH session detected, type in hostname of the machine to $CMD: "
-  read HOSTNAME_USER
+usage()
+{
+  cat <<-_eousage
+       Usage: $ME [options]
+              (shielding $EXEC)
+
+       Instead of invoking $EXEC directly, $ME will run a number of checks
+        to guard against accidental shutdowns/reboots.
+
+        Some of the checks available are:
+         - Prompt the user for the machine's if the current shell is a child
+           of an SSH connection (or --pretend-ssh) has been given on the
+           command line, if the shell is connected to an interactive
+          terminal, and the actual command to execute is does not involve
+           --help or is \`shutdown -c'.
+
+         $ME will always interpose the prompt if the environment variable
+          ALWAYS_MOLLY is set to '1'.  This variable may be set in the file
+         /etc/default/${ME} .
+
+        - Print out a warning message with information about this host
+         before the action takes place.  You can use:
+               /etc/molly-guard.<Action>.message
+         To print out a message specific to the command you're trying to
+         use.  Or:
+               /etc/molly-guard.message
+         For a general warning message.
+
+       Only if the user satisfies all the checks will $ME take action.
+       Specifying --molly-guard-do-nothing as argument to the command will
+       make $ME echo the command it would execute rather than actually executing
+       it.
 
-  HOSTNAME="$(hostname)"
+       The actual command's help output follows:
 
-  if [ "$HOSTNAME_USER" != "$HOSTNAME" ]; then
-    echo "Good thing I asked; I won't $CMD $HOSTNAME ..."
-    exit 2
+       _eousage
+}
+
+ARGS=
+DO_NOTHING=0
+CHECK_ARGS=
+for arg in "$@"; do
+  case "$arg" in
+    (*-molly-guard-do-nothing) DO_NOTHING=1;;
+    (*-help)
+      usage 2>&1
+      eval $EXEC --help 2>&1
+      exit 0
+      ;;
+    (*-pretend-ssh) CHECK_ARGS="${CHECK_ARGS:+$CHECK_ARGS }--arg --pretend-ssh";;
+    *) ARGS="${ARGS:+$ARGS }$arg";;
+  esac
+done
+
+do_real_cmd()
+{
+  if [ $DO_NOTHING -eq 1 ]; then
+    echo "$ME: would run: $EXEC $ARGS"
+    exit 0
+  else
+    eval exec $EXEC "$ARGS"
   fi
+}
+
+if [ $DO_NOTHING -eq 1 ]; then
+  echo "I: demo mode; $ME will not do anything due to --molly-guard-do-nothing."
 fi
 
-exec $EXEC "$@"
+# pass through certain commands
+case "$CMD $ARGS" in
+  (*shutdown\ *-c*) 
+    echo "I: executing $CMD $ARGS regardless of check results."
+    do_real_cmd
+    ;;
+esac
+
+run-parts --exit-on-error $CHECK_ARGS /usr/share/molly-guard/checks.d
+
+# run-parts won't return to us if there are failures, but I'm paranoid.
+if [ $? == 0 ]; then
+  do_real_cmd
+  exit
+fi