write warnings and info messages to stderr

[code/molly-guard.git] / shutdown

diff --git a/shutdown b/shutdown
index c9b34f2190e68d41bdea5685375506e79bc723a9..2e24f7fdfa29a616d569804b50aa130f8df8d5d2 100755 (executable)
--- a/shutdown
+++ b/shutdown
@@ -1,21 +1,22 @@
 #!/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: $EXEC" >&2
       exit 4
@@ -30,48 +31,88 @@ case "$CMD" in
     exit 1
     ;;
 esac
-ARGS="$@"
 
-do_real_cmd()
+usage()
 {
-  case "$ARGS" in
-    (*--molly-guard-do-nothing*)
-      ARGS0="${ARGS%% --molly-guard-do-nothing*}"
-      ARGS1="${ARGS##*--molly-guard-do-nothing}"
-      echo "$ME: would run: $EXEC $ARGS0 ${ARGS1# }"
-      exit 0;;
-    *) eval exec $EXEC "$ARGS";;
-  esac
-}
+  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.
 
-# require $SSH_CONNECTION to be set, indicates an SSH session
-[ -n "${SSH_CONNECTION:-}" ] || do_real_cmd
-# require an interactive terminal connected to stdin
-test -t 0                    || do_real_cmd
-# pass through help commands
-case "$CMD $ARGS" in
-  (shutdown\ *-c*) do_real_cmd;;
-  (shutdown\ *-h*) do_real_cmd;;
-  (*--help*) do_real_cmd;;
-  *) :;;
-esac
+       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.
 
-HOSTNAME="$(hostname)"
+       The actual command's help output follows:
 
-sigh()
+       _eousage
+}
+
+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()
 {
-  echo "Good thing I asked; I won't $CMD $HOSTNAME ..."
-  exit 2
+  if [ $DO_NOTHING -eq 1 ]; then
+    echo "$ME: would run: $EXEC $CMDARGS"
+    exit 0
+  else
+    eval exec $EXEC "$CMDARGS"
+  fi
 }
 
-trap 'echo;sigh' 1 2 3 9 10 12 15
+if [ $DO_NOTHING -eq 1 ]; then
+  echo "I: demo mode; $ME will not do anything due to --molly-guard-do-nothing." >&2
+fi
 
-echo "$ME: SSH session detected!"
-echo -n "Please type in hostname of the machine to $CMD: "
-read HOSTNAME_USER || :
+# pass through certain commands
+case "$CMD $CMDARGS" in
+  (*shutdown\ *-c*)
+    # allow canceling shutdowns
+    echo "I: executing $CMD $CMDARGS regardless of check results." >&2
+    do_real_cmd
+    ;;
+esac
 
-[ "$HOSTNAME_USER" = "$HOSTNAME" ] || sigh
+MOLLYGUARD_CMD=$CMD; export MOLLYGUARD_CMD
+MOLLYGUARD_DO_NOTHING=$DO_NOTHING; export MOLLYGUARD_DO_NOTHING
+MOLLYGUARD_SETTINGS="/etc/default/$ME"; export MOLLYGUARD_SETTINGS
 
-trap - 1 2 3 9 10 12 15
+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