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Ignore some of the build files.
[code/molly-guard.git] / shutdown
1 #!/bin/sh
2 #
3 # shutdown -- wrapper script to prevent erroneous shutdowns via SSH
4 #
5 # Copyright © martin f. krafft <madduck@madduck.net>
6 # Released under the terms of the Artistic Licence 2.0
7 #
8 # $Id: shutdown 299 2006-10-16 14:40:47Z madduck $
9 #
10 set -eu
11
12 ME=molly-guard
13
14 CMD="${0##*/}"
15 EXEC="/sbin/$CMD"
16
17 case "$CMD" in
18   halt|reboot|shutdown|poweroff)
19     if [ ! -f $EXEC ]; then
20       echo "E: $ME: not a regular file: $EXEC" >&2
21       exit 4
22     fi
23     if [ ! -x $EXEC ]; then
24       echo "E: $ME: not an executable: $EXEC" >&2
25       exit 3
26     fi
27     ;;
28   *)
29     echo "E: $ME: unsupported command: $CMD" >&2
30     exit 1
31     ;;
32 esac
33
34 usage()
35 {
36   cat <<-_eousage
37         Usage: $ME [options]
38                (shielding $EXEC)
39
40         Instead of invoking $EXEC directly, $ME will run a number of checks
41         to guard against accidental shutdowns/reboots.
42
43         Some of the checks available are:
44          - Prompt the user for the machine's if the current shell is a child
45            of an SSH connection (or --pretend-ssh) has been given on the
46            command line, if the shell is connected to an interactive
47            terminal, and the actual command to execute is does not involve
48            --help or is \`shutdown -c'.
49
50           $ME will always interpose the prompt if the environment variable
51           ALWAYS_MOLLY is set to '1'.  This variable may be set in the file
52           /etc/default/${ME} .
53
54         - Print out a warning message with information about this host
55           before the action takes place.  You can use:
56                 /etc/molly-guard.<Action>.message
57           To print out a message specific to the command you're trying to
58           use.  Or:
59                 /etc/molly-guard.message
60           For a general warning message.
61
62         Only if the user satisfies all the checks will $ME take action.
63         Specifying --molly-guard-do-nothing as argument to the command will
64         make $ME echo the command it would execute rather than actually executing
65         it.
66
67         The actual command's help output follows:
68
69         _eousage
70 }
71
72 ARGS=
73 DO_NOTHING=0
74 CHECK_ARGS=
75 for arg in "$@"; do
76   case "$arg" in
77     (*-molly-guard-do-nothing) DO_NOTHING=1;;
78     (*-help)
79       usage 2>&1
80       eval $EXEC --help 2>&1
81       exit 0
82       ;;
83     (*-pretend-ssh) CHECK_ARGS="${CHECK_ARGS:+$CHECK_ARGS }--arg --pretend-ssh";;
84     *) ARGS="${ARGS:+$ARGS }$arg";;
85   esac
86 done
87
88 do_real_cmd()
89 {
90   if [ $DO_NOTHING -eq 1 ]; then
91     echo "$ME: would run: $EXEC $ARGS"
92     exit 0
93   else
94     eval exec $EXEC "$ARGS"
95   fi
96 }
97
98 if [ $DO_NOTHING -eq 1 ]; then
99   echo "I: demo mode; $ME will not do anything due to --molly-guard-do-nothing."
100 fi
101
102 # pass through certain commands
103 case "$CMD $ARGS" in
104   (*shutdown\ *-c*) 
105     echo "I: executing $CMD $ARGS regardless of check results."
106     do_real_cmd
107     ;;
108 esac
109
110 run-parts --exit-on-error $CHECK_ARGS /usr/share/molly-guard/checks.d
111
112 # run-parts won't return to us if there are failures, but I'm paranoid.
113 if [ $? == 0 ]; then
114   do_real_cmd
115   exit
116 fi