mailinabox/setup/functions.sh

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function hide_output {
# This function hides the output of a command unless the command fails
# and returns a non-zero exit code.
# Get a temporary file.
OUTPUT=$(tempfile)
# Execute command, redirecting stderr/stdout to the temporary file.
$@ &> $OUTPUT
# If the command failed, show the output that was captured in the temporary file.
if [ $? != 0 ]; then
# Something failed.
echo
echo FAILED: $@
echo -----------------------------------------
cat $OUTPUT
echo -----------------------------------------
fi
# Remove temporary file.
rm -f $OUTPUT
}
function apt_get_quiet {
# Run apt-get in a totally non-interactive mode.
#
# Somehow all of these options are needed to get it to not ask the user
# questions about a) whether to proceed (-y), b) package options (noninteractive),
# and c) what to do about files changed locally (we don't cause that to happen but
# some VM providers muck with their images; -o).
#
# Although we could pass -qq to apt-get to make output quieter, many packages write to stdout
# and stderr things that aren't really important. Use our hide_output function to capture
# all of that and only show it if there is a problem (i.e. if apt_get returns a failure exit status).
DEBIAN_FRONTEND=noninteractive hide_output apt-get -y -o Dpkg::Options::="--force-confdef" -o Dpkg::Options::="--force-confnew" "$@"
}
function apt_install {
# Report any packages already installed.
PACKAGES=$@
TO_INSTALL=""
ALREADY_INSTALLED=""
for pkg in $PACKAGES; do
if dpkg -s $pkg 2>/dev/null | grep "^Status: install ok installed" > /dev/null; then
if [[ ! -z "$ALREADY_INSTALLED" ]]; then ALREADY_INSTALLED="$ALREADY_INSTALLED, "; fi
ALREADY_INSTALLED="$ALREADY_INSTALLED$pkg (`dpkg -s $pkg | grep ^Version: | sed -e 's/.*: //'`)"
else
TO_INSTALL="$TO_INSTALL""$pkg "
fi
done
# List the packages already installed.
if [[ ! -z "$ALREADY_INSTALLED" ]]; then
echo already installed: $ALREADY_INSTALLED
fi
# List the packages about to be installed.
if [[ ! -z "$TO_INSTALL" ]]; then
echo installing $TO_INSTALL...
fi
# We still include the whole original package list in the apt-get command in
# case it wants to upgrade anything, I guess? Maybe we can remove it. Doesn't normally make
# a difference.
apt_get_quiet install $PACKAGES
}
function get_default_hostname {
# Guess the machine's hostname. It should be a fully qualified
# domain name suitable for DNS. None of these calls may provide
# the right value, but it's the best guess we can make.
set -- $(hostname --fqdn 2>/dev/null ||
hostname --all-fqdns 2>/dev/null ||
hostname 2>/dev/null)
printf '%s\n' "$1" # return this value
}
function get_publicip_from_web_service {
# This seems to be the most reliable way to determine the
# machine's public IP address: asking a very nice web API
# for how they see us. Thanks go out to icanhazip.com.
# See: https://major.io/icanhazip-com-faq/
#
# Pass '4' or '6' as an argument to this function to specify
# what type of address to get (IPv4, IPv6).
curl -$1 --fail --silent --max-time 15 icanhazip.com 2>/dev/null
}
function get_default_privateip {
# Return the IP address of the network interface connected
# to the Internet.
#
# Pass '4' or '6' as an argument to this function to specify
# what type of address to get (IPv4, IPv6).
#
# We used to use `hostname -I` and then filter for either
# IPv4 or IPv6 addresses. However if there are multiple
# network interfaces on the machine, not all may be for
# reaching the Internet.
#
# Instead use `ip route get` which asks the kernel to use
# the system's routes to select which interface would be
# used to reach a public address. We'll use 8.8.8.8 as
# the destination. It happens to be Google Public DNS, but
# no connection is made. We're just seeing how the box
# would connect to it. There many be multiple IP addresses
# assigned to an interface. `ip route get` reports the
# preferred. That's good enough for us. See issue #121.
#
# With IPv6, the best route may be via an interface that
# only has a link-local address (fe80::*). These addresses
# are only unique to an interface and so need an explicit
# interface specification in order to use them with bind().
# In these cases, we append "%interface" to the address.
# See the Notes section in the man page for getaddrinfo and
# https://discourse.mailinabox.email/t/update-broke-mailinabox/34/9.
#
# Also see ae67409603c49b7fa73c227449264ddd10aae6a9 and
# issue #3 for why/how we originally added IPv6.
target=8.8.8.8
# For the IPv6 route, use the corresponding IPv6 address
# of Google Public DNS. Again, it doesn't matter so long
# as it's an address on the public Internet.
if [ "$1" == "6" ]; then target=2001:4860:4860::8888; fi
# Get the route information.
route=$(ip -$1 -o route get $target | grep -v unreachable)
# Parse the address out of the route information.
address=$(echo $route | sed "s/.* src \([^ ]*\).*/\1/")
if [[ "$1" == "6" && $address == fe80:* ]]; then
# For IPv6 link-local addresses, parse the interface out
# of the route information and append it with a '%'.
interface=$(echo $route | sed "s/.* dev \([^ ]*\).*/\1/")
address=$address%$interface
fi
echo $address
}
function ufw_allow {
if [ -z "$DISABLE_FIREWALL" ]; then
# ufw has completely unhelpful output
ufw allow $1 > /dev/null;
fi
}
function restart_service {
hide_output service $1 restart
}
## Dialog Functions ##
function message_box {
dialog --title "$1" --msgbox "$2" 0 0
}
function input_box {
# input_box "title" "prompt" "defaultvalue" VARIABLE
# The user's input will be stored in the variable VARIABLE.
# The exit code from dialog will be stored in VARIABLE_EXITCODE.
declare -n result=$4
declare -n result_code=$4_EXITCODE
result=$(dialog --stdout --title "$1" --inputbox "$2" 0 0 "$3")
result_code=$?
}
function input_menu {
# input_menu "title" "prompt" "tag item tag item" VARIABLE
# The user's input will be stored in the variable VARIABLE.
# The exit code from dialog will be stored in VARIABLE_EXITCODE.
declare -n result=$4
declare -n result_code=$4_EXITCODE
local IFS=^$'\n'
result=$(dialog --stdout --title "$1" --menu "$2" 0 0 0 $3)
result_code=$?
}