postgresql: update to version 9.5.4 and major rework

* convert package build to use host-build for ecpg, pg_config and zic
 * introduce /lib/functions/postgresql.sh to be used by packages
   requiring a postgres database to exist as well as postgres' init
 * no longer require shadow-su, patch pg_ctl to setuid() ifself instead
 * auto-create database directory if there is enough free space
 * auto-create databases configured in UCI
 * remove some dead uci config options
 * grab maintainership

Signed-off-by: Daniel Golle <daniel@makrotopia.org>

libs/postgresql/files/postgresql.sh

@@ -0,0 +1,60 @@
+#!/bin/sh
+
+PSQL="/usr/bin/psql"
+
+free_megs() {
+	fsdir=$1
+	while [ ! -d "$fsdir" ]; do
+		fsdir=$(dirname $fsdir)
+	done
+	df -m $fsdir | while read fs bl us av cap mnt; do [ "$av" = "Available" ] || echo $av; done
+}
+
+pg_init_data() {
+	# make sure we got at least 50MB of free space
+	[ $(free_megs $1) -lt 50 ] && return 1
+	pg_ctl initdb -U postgres -D $1
+}
+
+pg_server_ready() {
+	t=0
+	while [ $t -le 90 ]; do
+		pg_ctl status -U postgres -D $1 2>/dev/null >/dev/null && return 0
+		t=$((t+1))
+		sleep 1
+	done
+	return 1
+}
+
+# $1: dbname, $2: username, $3: password
+pg_require_db() {
+	pg_test_db $@ && return 0
+	( echo "CREATE DATABASE $1;"
+	echo -n "CREATE USER $2"
+	[ "$3" ] && echo -n " WITH PASSWORD '$3'"
+	echo ";"
+	echo "GRANT ALL PRIVILEGES ON DATABASE \"$1\" to $2;" ) |
+		$PSQL -U postgres -d template1 -e
+	return $?
+}
+
+pg_test_db() {
+	PGPASSWORD=$3
+	echo "SHOW ALL;" | $PSQL -U $2 -d $1 -q 2>/dev/null >/dev/null
+	return $?
+}
+
+uci_require_db() {
+	local dbname dbuser dbpass
+	config_get dbname $1 name
+	config_get dbuser $1 user
+	config_get dbpass $1 pass
+	pg_require_db $dbname $dbuser $dbpass
+}
+
+[ "$1" = "init" ] && {
+	. /lib/functions.sh
+	pg_server_ready $2 || exit 1
+	config_load postgresql
+	config_foreach uci_require_db postgres-db
+}