mailinabox/setup/functions.sh

223 lines
7.4 KiB
Bash
Raw Permalink Normal View History

# Turn on "strict mode." See http://redsymbol.net/articles/unofficial-bash-strict-mode/.
# -e: exit if any command unexpectedly fails.
# -u: exit if we have a variable typo.
# -o pipefail: don't ignore errors in the non-last command in a pipeline
set -euo pipefail
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=$(mktemp)
# Execute command, redirecting stderr/stdout to the temporary file. Since we
# check the return code ourselves, disable 'set -e' temporarily.
set +e
"$@" &> $OUTPUT
E=$?
set -e
# If the command failed, show the output that was captured in the temporary file.
if [ $E != 0 ]; then
# Something failed.
echo
echo FAILED: "$@"
echo -----------------------------------------
cat $OUTPUT
echo -----------------------------------------
exit $E
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 {
# Install a bunch of packages. We used to report which packages were already
# installed and which needed installing, before just running an 'apt-get
# install' for all of the packages. Calling `dpkg` on each package is slow,
# and doesn't affect what we actually do, except in the messages, so let's
# not do that anymore.
apt_get_quiet install "$@"
}
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 || /bin/true
}
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 $target 2>/dev/null | grep -v unreachable)
# Parse the address out of the route information.
address=$(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 "$1" > /dev/null;
fi
}
function ufw_limit {
if [ -z "${DISABLE_FIREWALL:-}" ]; then
# ufw has completely unhelpful output
ufw limit "$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 {
2014-08-21 15:52:19 +00:00
# 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.
# Temporarily turn off 'set -e' because we need the dialog return code.
2014-08-21 15:52:19 +00:00
declare -n result=$4
declare -n result_code=$4_EXITCODE
set +e
2014-08-21 15:52:19 +00:00
result=$(dialog --stdout --title "$1" --inputbox "$2" 0 0 "$3")
result_code=$?
set -e
}
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'
set +e
result=$(dialog --stdout --title "$1" --menu "$2" 0 0 0 $3)
result_code=$?
set -e
}
function wget_verify {
# Downloads a file from the web and checks that it matches
# a provided hash. If the comparison fails, exit immediately.
URL=$1
HASH=$2
DEST=$3
CHECKSUM="$HASH $DEST"
rm -f $DEST
hide_output wget -O $DEST $URL
if ! echo "$CHECKSUM" | sha1sum --check --strict > /dev/null; then
echo "------------------------------------------------------------"
echo "Download of $URL did not match expected checksum."
echo "Found:"
sha1sum $DEST
echo
echo "Expected:"
echo "$CHECKSUM"
rm -f $DEST
exit 1
fi
}
function git_clone {
# Clones a git repository, checks out a particular commit or tag,
# and moves the repository (or a subdirectory in it) to some path.
# We use separate clone and checkout because -b only supports tags
# and branches, but we sometimes want to reference a commit hash
# directly when the repo doesn't provide a tag.
REPO=$1
TREEISH=$2
SUBDIR=$3
TARGETPATH=$4
TMPPATH=/tmp/git-clone-$$
rm -rf $TMPPATH $TARGETPATH
git clone -q $REPO $TMPPATH || exit 1
(cd $TMPPATH; git checkout -q $TREEISH;) || exit 1
mv $TMPPATH/$SUBDIR $TARGETPATH
rm -rf $TMPPATH
}