Improve bash quoting, and other similar best practices

This patch updates the shell scripts with some of the common best
practices, which should make them more resilient to unusual failures and
unexpected environments (in particular, directories with spaces).

Most of these were identified by shellcheck.

test/util/lib.sh

@@ -1,3 +1,4 @@
+#!/bin/bash
 # Library to write the shell scripts in the tests.
 
 function init() {
@@ -5,10 +6,11 @@ function init() {
 		set -v
 	fi
 
-	export UTILDIR="$( realpath `dirname "${BASH_SOURCE[0]}"` )"
+	UTILDIR=$(realpath "$(dirname "${BASH_SOURCE[0]}")" )
+	export UTILDIR
 
-	export TBASE="$(realpath `dirname ${0}`)"
-	cd ${TBASE}
+	TBASE=$(realpath "$(dirname "$0")" )
+	cd "${TBASE}" || exit 1
 
 	if [ "${RACE}" == "1" ]; then
 		GOFLAGS="$GOFLAGS -race"
@@ -30,7 +32,8 @@ function chasquid() {
 		return
 	fi
 
-	( cd ${TBASE}/../../; go build $GOFLAGS -tags="$GOTAGS" . )
+	# shellcheck disable=SC2086
+	( cd "${TBASE}/../../" || exit 1; go build $GOFLAGS -tags="$GOTAGS" . )
 
 	# HOSTALIASES: so we "fake" hostnames.
 	# PATH: so chasquid can call test-mda without path issues.
@@ -38,13 +41,14 @@ function chasquid() {
 	HOSTALIASES=${TBASE}/hosts \
 	PATH=${UTILDIR}:${PATH} \
 	MDA_DIR=${TBASE}/.mail \
-		${TBASE}/../../chasquid "$@"
+		"${TBASE}/../../chasquid" "$@"
 }
 
 function chasquid_cover() {
 	# Build the coverage-enabled binary.
 	# See coverage_test.go for more details.
-	( cd ${TBASE}/../../;
+	# shellcheck disable=SC2086
+	( cd "${TBASE}/../../" || exit 1;
 	  go test -covermode=count -coverpkg=./... -c \
 		  -tags="coveragebin $GOTAGS" $GOFLAGS )
 
@@ -54,9 +58,9 @@ function chasquid_cover() {
 	HOSTALIASES=${TBASE}/hosts \
 	PATH=${UTILDIR}:${PATH} \
 	MDA_DIR=${TBASE}/.mail \
-		${TBASE}/../../chasquid.test \
+		"${TBASE}/../../chasquid.test" \
 			-test.run "^TestRunMain$" \
-			-test.coverprofile="$COVER_DIR/test-`date +%s.%N`.out" \
+			-test.coverprofile="$COVER_DIR/test-$(date +%s.%N).out" \
 			"$@"
 }
 
@@ -65,9 +69,9 @@ function chasquid_cover() {
 # use the simpler add_user (below) for testing purposes.
 function chasquid-util-user-add() {
 	CONFDIR="${CONFDIR:-config}"
-	DOMAIN=$(echo $1 | cut -d @ -f 2)
+	DOMAIN=$(echo "$1" | cut -d @ -f 2)
 	mkdir -p "${CONFDIR}/domains/$DOMAIN/"
-	go run ${TBASE}/../../cmd/chasquid-util/chasquid-util.go \
+	go run "${TBASE}/../../cmd/chasquid-util/chasquid-util.go" \
 		-C="${CONFDIR}" \
 		user-add "$1" \
 		--password="$2" \
@@ -76,8 +80,8 @@ function chasquid-util-user-add() {
 
 function add_user() {
 	CONFDIR="${CONFDIR:-config}"
-	USERNAME=$(echo $1 | cut -d @ -f 1)
-	DOMAIN=$(echo $1 | cut -d @ -f 2)
+	USERNAME=$(echo "$1" | cut -d @ -f 1)
+	DOMAIN=$(echo "$1" | cut -d @ -f 2)
 	USERDB="${CONFDIR}/domains/$DOMAIN/users"
 	mkdir -p "${CONFDIR}/domains/$DOMAIN/"
 	if ! [ -f "${USERDB}" ] || ! grep -E -q "key:.*${USERNAME}" "${USERDB}"; then
@@ -87,7 +91,7 @@ function add_user() {
 }
 
 function dovecot-auth-cli() {
-	go run ${TBASE}/../../cmd/dovecot-auth-cli/dovecot-auth-cli.go "$@"
+	go run "${TBASE}/../../cmd/dovecot-auth-cli/dovecot-auth-cli.go" "$@"
 }
 
 function run_msmtp() {
@@ -97,54 +101,54 @@ function run_msmtp() {
 	# msmtp binary is often g+s, which causes $HOSTALIASES to not be
 	# honoured, which breaks the tests. Copy the binary to remove the
 	# setgid bit as a workaround.
-	cp -u "`command -v msmtp`" "${UTILDIR}/.msmtp-bin"
+	cp -u "$(command -v msmtp)" "${UTILDIR}/.msmtp-bin"
 
 	HOSTALIASES=${TBASE}/hosts \
-		${UTILDIR}/.msmtp-bin -C msmtprc "$@"
+		"${UTILDIR}/.msmtp-bin" -C msmtprc "$@"
 }
 
 function smtpc.py() {
-	${UTILDIR}/smtpc.py "$@"
+	"${UTILDIR}/smtpc.py" "$@"
 }
 
 function mail_diff() {
-	${UTILDIR}/mail_diff "$@"
+	"${UTILDIR}/mail_diff" "$@"
 }
 
 function chamuyero() {
-	${UTILDIR}/chamuyero "$@"
+	"${UTILDIR}/chamuyero" "$@"
 }
 
 function generate_cert() {
-	( cd ${UTILDIR}/generate_cert/; go build )
-	${UTILDIR}/generate_cert/generate_cert "$@"
+	( cd "${UTILDIR}/generate_cert/" || exit 1; go build )
+	"${UTILDIR}/generate_cert/generate_cert" "$@"
 }
 
 function loadgen() {
-	( cd ${UTILDIR}/loadgen/; go build )
-	${UTILDIR}/loadgen/loadgen "$@"
+	( cd "${UTILDIR}/loadgen/" || exit 1; go build )
+	"${UTILDIR}/loadgen/loadgen" "$@"
 }
 
 function conngen() {
-	( cd ${UTILDIR}/conngen/; go build )
-	${UTILDIR}/conngen/conngen "$@"
+	( cd "${UTILDIR}/conngen/" || exit 1; go build )
+	"${UTILDIR}/conngen/conngen" "$@"
 }
 
 function minidns_bg() {
-	( cd ${UTILDIR}/minidns; go build )
-	${UTILDIR}/minidns/minidns "$@" &
-	MINIDNS=$!
+	( cd "${UTILDIR}/minidns" || exit 1; go build )
+	"${UTILDIR}/minidns/minidns" "$@" &
+	export MINIDNS=$!
 }
 
 function fexp() {
-	( cd ${UTILDIR}/fexp/; go build )
-	${UTILDIR}/fexp/fexp "$@"
+	( cd "${UTILDIR}/fexp/" || exit 1; go build )
+	"${UTILDIR}/fexp/fexp" "$@"
 }
 
 function timeout() {
 	MYPID=$$
 	(
-		sleep $1
+		sleep "$1"
 		echo "timed out after $1, killing test"
 		kill -9 $MYPID
 	) &
@@ -155,18 +159,18 @@ function success() {
 }
 
 function skip() {
-	echo skipped: $*
+	echo "skipped: $*"
 	exit 0
 }
 
 function fail() {
-	echo FAILED: $*
+	echo "FAILED: $*"
 	exit 1
 }
 
 function check_hostaliases() {
 	if ! "${UTILDIR}/check-hostaliases"; then
-		skip '$HOSTALIASES not working (probably systemd-resolved)'
+		skip "\$HOSTALIASES not working (probably systemd-resolved)"
 	fi
 }
 
@@ -181,14 +185,14 @@ function wait_until_ready() {
 
 # Wait for the given file to exist.
 function wait_for_file() {
-	while ! [ -e ${1} ]; do
+	while ! [ -e "$1" ]; do
 		sleep 0.01
 	done
 }
 
 function wait_until() {
 	while true; do
-		if eval "$@"; then
+		if eval "$*"; then
 			return 0
 		fi
 		sleep 0.01
@@ -204,16 +208,16 @@ function generate_certs_for() {
 	CACHEDIR="${TBASE}/../.generate_certs_cache"
 	mkdir -p "${CACHEDIR}"
 	touch -d "10 minutes ago" "${CACHEDIR}/.reference"
-	if [ "${CACHEDIR}/${1}/" -ot "${CACHEDIR}/.reference" ]; then
+	if [ "${CACHEDIR}/$1/" -ot "${CACHEDIR}/.reference" ]; then
 		# Cache miss (either was not there, or was too old).
-		mkdir -p "${CACHEDIR}/${1}/"
+		mkdir -p "${CACHEDIR}/$1/"
 		(
-			cd "${CACHEDIR}/${1}/"
-			generate_cert -ca -validfor=1h -host=${1}
+			cd "${CACHEDIR}/$1/" || exit 1
+			generate_cert -ca -validfor=1h -host="$1"
 		)
 	fi
-	mkdir -p "${CONFDIR}/certs/${1}/"
-	cp -p "${CACHEDIR}/${1}"/* "${CONFDIR}/certs/${1}/"
+	mkdir -p "${CONFDIR}/certs/$1/"
+	cp -p "${CACHEDIR}/$1"/* "${CONFDIR}/certs/$1/"
 }
 
 # Check the Python version, and skip if it's too old.
@@ -229,7 +233,6 @@ function skip_if_python_is_too_old() {
 function chasquid_ram_peak() {
 	# Find the pid of the daemon, which we expect is running on the
 	# background somewhere within our current session.
-	SERVER_PID=`pgrep -s 0 -x chasquid`
-
-	echo $( cat /proc/$SERVER_PID/status | grep VmHWM | cut -d ':' -f 2- )
+	SERVER_PID=$(pgrep -s 0 -x chasquid)
+	grep VmHWM "/proc/$SERVER_PID/status" | cut -d ':' -f 2-
 }