Commit | Line | Data |
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775bd287 | 1 | ### -*-sh-*- |
bfdc045d MW |
2 | ### |
3 | ### Failsafe prologue for firewall scripts | |
4 | ### | |
5 | ### (c) 2008 Mark Wooding | |
6 | ### | |
7 | ||
8 | ###----- Licensing notice --------------------------------------------------- | |
9 | ### | |
10 | ### This program is free software; you can redistribute it and/or modify | |
11 | ### it under the terms of the GNU General Public License as published by | |
12 | ### the Free Software Foundation; either version 2 of the License, or | |
13 | ### (at your option) any later version. | |
14 | ### | |
15 | ### This program is distributed in the hope that it will be useful, | |
16 | ### but WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | ### MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
18 | ### GNU General Public License for more details. | |
19 | ### | |
20 | ### You should have received a copy of the GNU General Public License | |
21 | ### along with this program; if not, write to the Free Software Foundation, | |
22 | ### Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
23 | ||
24 | m4_divert(10)m4_dnl | |
25 | ###-------------------------------------------------------------------------- | |
26 | ### Failsafe prologue. | |
27 | ||
28 | revert () { | |
d8eafff6 MW |
29 | escape=$1 badness=$2 |
30 | ## Report a firewall script failure and retreat to a safe place. | |
31 | ||
32 | echo "$2! Retreating to safe version..." | |
33 | if ! "$1" revert; then | |
bfdc045d MW |
34 | echo >&2 "Safe firewall failed. You're screwed. Good luck." |
35 | exit 1 | |
36 | fi | |
37 | echo >&2 "Phew! Fallback to safe version successful." | |
38 | exit 1 | |
39 | } | |
40 | ||
41 | finished () { | |
42 | echo "Done." | |
43 | exit 0 | |
44 | } | |
45 | ||
d8eafff6 MW |
46 | try () { |
47 | old=$1 new=$2 | |
48 | ## Install the NEW firewall rules. If it fails, revert to the OLD ones. | |
49 | ## Updating firewall rules can fail spectacularly, so be careful. Leave a | |
50 | ## timebomb in the form of NEW.errors: if this isn't removed in 10 seconds | |
51 | ## after the NEW rules complete successfully, then revert. Write errors to | |
52 | ## NEW.errors. | |
53 | ||
54 | ## Make sure we have an escape route. | |
55 | if [ ! -x "$old" ]; then | |
56 | echo >&2 "$0: no escape plan: \`$old' is missing" | |
57 | exit 1 | |
58 | fi | |
59 | ||
60 | ## Clear the air and make the errors file. | |
61 | rm -f "$new.errors" "$new.timebomb" "$new.grabbed" | |
62 | exec >"$new.errors" 2>&1 | |
63 | ||
64 | ## Now try to install the new firewall. | |
65 | "$new" install || revert "$old" "Failed" | |
66 | ||
67 | ## Set up the time bomb. Leave the errors file there if we failed. | |
68 | (sleep 10 | |
69 | if [ -f "$new.errors" ]; then | |
70 | mv "$new.errors" "$new.timebomb" | |
71 | revert "$old" "Time bomb" | |
72 | fi)& | |
73 | } | |
74 | ||
75 | catch () { | |
76 | new=$1 | |
77 | ## Report successful installation of the script. | |
78 | ||
79 | if mv "$new.errors" "$new.grabbed" 2>/dev/null; then | |
80 | rc=0 | |
81 | echo "Installed OK." | |
82 | else | |
83 | mv "$new.timebomb" "$new.grabbed" | |
84 | echo "Timebomb went off." | |
85 | rc=1 | |
86 | fi | |
87 | cat "$new.grabbed" >&2 | |
88 | rm -f "$new.grabbed" | |
89 | return $rc | |
90 | } | |
91 | ||
bfdc045d MW |
92 | exit_after_clearing=: |
93 | export FWCOOKIE=magical | |
d8eafff6 MW |
94 | case "$#,${1-update}" in |
95 | 1,start | 1,restart | 1,reload | 1,force-reload) | |
bfdc045d | 96 | echo -n "Starting up firewall... " |
d8eafff6 | 97 | "$firewall_script" install || revert "$firewall_failsafe" "Failed" |
bfdc045d MW |
98 | finished |
99 | ;; | |
d8eafff6 | 100 | 1,stop) |
bfdc045d MW |
101 | echo -n "Shutting down firewall... " |
102 | exit_after_clearing=finished | |
103 | ;; | |
d8eafff6 MW |
104 | 1,replace | 1,test) |
105 | echo -n "Running new firewall... " | |
106 | if ! (try "$firewall_script" "$0"); then | |
107 | echo "FAILED." | |
108 | cat "$0.errors" >&2 | |
109 | exit | |
110 | fi | |
111 | echo "done." | |
bfdc045d | 112 | echo "Can you hear me?" |
d8eafff6 MW |
113 | (trap 'exit 127' TERM |
114 | while :; do | |
115 | if [ -f "$0.timebomb" ]; then | |
116 | kill $$ | |
117 | echo "Timebomb went off!" | |
118 | cat "$0.timebomb" | |
119 | exit 1 | |
120 | fi | |
121 | sleep 1 | |
122 | done)& | |
bfdc045d | 123 | read answer |
d8eafff6 MW |
124 | kill $! |
125 | catch "$0" | |
126 | case "$1,$answer" in | |
127 | replace,y* | replace,Y*) | |
128 | install -m755 "$0" "$firewall_script" | |
129 | echo "Cool. Firewall script replaced." | |
bfdc045d MW |
130 | exit 0 |
131 | ;; | |
d8eafff6 MW |
132 | test,y* | test,Y*) |
133 | echo "Cool. Everything seems good." | |
134 | exit 0 | |
135 | ;; | |
136 | *) | |
137 | revert "$firewall_script" "Bogus" | |
138 | ;; | |
bfdc045d | 139 | esac |
bfdc045d | 140 | ;; |
d8eafff6 MW |
141 | 1,remote-prepare) |
142 | try "$firewall_script" "$0" | |
143 | exit 0 | |
144 | ;; | |
145 | 1,remote-commit) | |
146 | catch "$0" | |
147 | install -m755 "$0" "$firewall_script" | |
148 | exit 0 | |
149 | ;; | |
150 | 1,install | 1,revert) | |
bfdc045d MW |
151 | ;; |
152 | *) | |
d8eafff6 MW |
153 | cat >&2 <<EOF |
154 | Usage: | |
155 | $0 start|stop|reload|restart|force-reload | |
156 | $0 replace|test|remote-prepare|remote-commit | |
157 | EOF | |
bfdc045d MW |
158 | exit 1 |
159 | ;; | |
160 | esac | |
161 | ||
162 | m4_divert(-1) | |
163 | ###----- That's all, folks -------------------------------------------------- |