write warnings and info messages to stderr

[code/molly-guard.git] / shutdown

diff --git a/shutdown b/shutdown
index 0a6efd6011e590fea9ef6e80dc6ae0c2ce48fe37..2e24f7fdfa29a616d569804b50aa130f8df8d5d2 100755 (executable)
--- a/shutdown
+++ b/shutdown
@@ -1,39 +1,118 @@
 #!/bin/sh
 #
-# shutdown -- wrapper script to prevent erroneous shutdowns via SSH
+# shutdown -- wrapper script to guard against accidental shutdowns
 #
 # Copyright © martin f. krafft <madduck@madduck.net>
 # Released under the terms of the Artistic Licence 2.0
 #
-# $Id: shutdown 299 2006-10-16 14:40:47Z madduck $
-#
 set -eu
 
+ME=molly-guard
+VERSION=0.4
+SCRIPTSDIR=/etc/molly-guard/run.d
+SCRIPTSDIR="${0%/*}/run.d"
+
 CMD="${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] [-- script options]
+              (shielding $EXEC)
+       
+       molly-guard's primary goal is to guard against accidental
+       shutdowns/reboots. $ME will run all scripts in $SCRIPTSDIR and only
+       invokes $EXEC if all scripts exited successfully.
+
+       Specifying --molly-guard-do-nothing as argument to the command will
+       make $ME echo the command it would execute rather than actually
+       executing it.
+
+       Options following the double hyphen will be passed unchanged to the
+       scripts.
+
+       Please see molly-guard(8) for more information.
+
+       The actual command's help output follows:
 
-  HOSTNAME="$(hostname)"
+       _eousage
+}
 
-  if [ "$HOSTNAME_USER" != "$HOSTNAME" ]; then
-    echo "Good thing I asked; I won't $CMD $HOSTNAME ..."
-    exit 2
+CMDARGS=
+SCRIPTARGS=
+END_OF_ARGS=0
+DO_NOTHING=0
+for arg in "$@"; do
+  case "$arg" in
+    (*-molly-guard-do-nothing) DO_NOTHING=1;;
+    (*-help)
+      usage 2>&1
+      eval $EXEC --help 2>&1
+      exit 0
+      ;;
+    --) END_OF_ARGS=1;;
+    *) 
+      if [ $END_OF_ARGS -eq 0 ]; then
+        CMDARGS="${args:+$args }$arg"
+      else
+        SCRIPTARGS="${args:+$args }--arg $arg"
+      fi
+      ;;
+  esac
+done
+
+do_real_cmd()
+{
+  if [ $DO_NOTHING -eq 1 ]; then
+    echo "$ME: would run: $EXEC $CMDARGS"
+    exit 0
+  else
+    eval exec $EXEC "$CMDARGS"
   fi
+}
+
+if [ $DO_NOTHING -eq 1 ]; then
+  echo "I: demo mode; $ME will not do anything due to --molly-guard-do-nothing." >&2
 fi
 
-exec $EXEC "$@"
+# pass through certain commands
+case "$CMD $CMDARGS" in
+  (*shutdown\ *-c*)
+    # allow canceling shutdowns
+    echo "I: executing $CMD $CMDARGS regardless of check results." >&2
+    do_real_cmd
+    ;;
+esac
+
+MOLLYGUARD_CMD=$CMD; export MOLLYGUARD_CMD
+MOLLYGUARD_DO_NOTHING=$DO_NOTHING; export MOLLYGUARD_DO_NOTHING
+MOLLYGUARD_SETTINGS="/etc/default/$ME"; export MOLLYGUARD_SETTINGS
+
+for script in $(run-parts --test $SCRIPTSDIR); do
+  ret=0
+  eval $script $SCRIPTARGS || ret=$?
+  if [ $ret -ne 0 ]; then
+    echo "W: aborting $CMD due to ${script##*/} exiting with code $ret." >&2
+    exit $ret
+  fi
+done
+
+do_real_cmd