#!/bin/sh
# Based on the configure script from musl libc, MIT licensed

usage () {
cat <<EOF
Usage: $0 [OPTION]... [VAR=VALUE]...

To assign environment variables (e.g., CC, CFLAGS...), specify them as
VAR=VALUE.  See below for descriptions of some of the useful variables.

Defaults for the options are specified in brackets.

Configuration:
  --srcdir=DIR            source directory [detected]
  --environment-only      check environment only, no system libraries
  --static                prepare for static build

Installation directories:
  --prefix=PREFIX         main installation prefix [/usr/local]
  --exec-prefix=EPREFIX   installation prefix for executable files [PREFIX]

Fine tuning of the installation directories:
  --bindir=DIR            user executables [EPREFIX/bin]
  --sharedir=DIR          share directories [PREFIX/share]
  --mandir=DIR            man pages [PREFIX/share/man]

Optional features:
  --enable-lua            build with Lua support [auto]
  --enable-selinux        build with SELinux support [auto]
  --enable-acl            build with POSIX ACL support [auto]

Some influential environment variables:
  CC                      C compiler command [detected]
  CFLAGS                  C compiler flags [-Os -pipe ...]
  LDFLAGS                 Linker flags

Use these variables to override the choices made by configure.

EOF
exit 0
}

# Helper functions

quote () {
tr '\n' ' ' <<EOF | grep '^[-[:alnum:]_=,./:]* $' >/dev/null 2>&1 && { echo "$1" ; return 0 ; }
$1
EOF
printf %s\\n "$1" | sed -e "s/'/'\\\\''/g" -e "1s/^/'/" -e "\$s/\$/'/" -e "s#^'\([-[:alnum:]_,./:]*\)=\(.*\)\$#\1='\2#"
}
echo () { printf "%s\n" "$*" ; }
fail () { echo "$*" ; exit 1 ; }
fnmatch () { eval "case \"\$2\" in $1) return 0 ;; *) return 1 ;; esac" ; }
cmdexists () { type "$1" >/dev/null 2>&1 ; }
trycc () { test -z "$CC" && cmdexists "$1" && CC=$1 ; }

stripdir () {
while eval "fnmatch '*/' \"\${$1}\"" ; do eval "$1=\${$1%/}" ; done
}

trycppif () {
printf "checking preprocessor condition %s... " "$1"
echo "typedef int x;" > "$tmpc"
echo "#if $1" >> "$tmpc"
echo "#error yes" >> "$tmpc"
echo "#endif" >> "$tmpc"
if $CC $2 -c -o "$tmpo" "$tmpc" >/dev/null 2>&1 ; then
printf "false\n"
return 1
else
printf "true\n"
return 0
fi
}

tryflag () {
printf "checking whether compiler accepts %s... " "$2"
echo "typedef int x;" > "$tmpc"
if $CC $CFLAGS_TRY $2 -c -o "$tmpo" "$tmpc" >/dev/null 2>&1 ; then
printf "yes\n"
eval "$1=\"\${$1} \$2\""
eval "$1=\${$1# }"
return 0
else
printf "no\n"
return 1
fi
}

tryldflag () {
printf "checking whether linker accepts %s... " "$2"
echo "typedef int x;" > "$tmpc"
if $CC $LDFLAGS_TRY -nostdlib -shared "$2" -o "$tmpo" "$tmpc" >/dev/null 2>&1 ; then
printf "yes\n"
eval "$1=\"\${$1} \$2\""
eval "$1=\${$1# }"
return 0
else
printf "no\n"
return 1
fi
}

# Beginning of actual script

CFLAGS_AUTO=
CFLAGS_TRY=
LDFLAGS_AUTO=
LDFLAGS_TRY=
SRCDIR=
PREFIX=/usr/local
EXEC_PREFIX='$(PREFIX)'
BINDIR='$(EXEC_PREFIX)/bin'
SHAREDIR='$(PREFIX)/share'
MANDIR='$(PREFIX)/share/man'

lua=auto
selinux=auto
acl=auto

for arg ; do
case "$arg" in
--help|-h) usage ;;
--srcdir=*) SRCDIR=${arg#*=} ;;
--prefix=*) PREFIX=${arg#*=} ;;
--exec-prefix=*) EXEC_PREFIX=${arg#*=} ;;
--bindir=*) BINDIR=${arg#*=} ;;
--sharedir=*) SHAREDIR=${arg#*=} ;;
--mandir=*) MANDIR=${arg#*=} ;;
--environment-only) environmentonly=yes ;;
--static) static=yes ;;
--enable-lua|--enable-lua=yes) lua=yes ;;
--disable-lua|--enable-lua=no) lua=no ;;
--enable-selinux|--enable-selinux=yes) selinux=yes ;;
--disable-selinux|--enable-selinux=no) selinux=no ;;
--enable-acl|--enable-acl=yes) acl=yes ;;
--disable-acl|--enable-acl=no) acl=no ;;
--enable-*|--disable-*|--with-*|--without-*|--*dir=*|--build=*) ;;
-* ) echo "$0: unknown option $arg" ;;
CC=*) CC=${arg#*=} ;;
CFLAGS=*) CFLAGS=${arg#*=} ;;
CPPFLAGS=*) CPPFLAGS=${arg#*=} ;;
LDFLAGS=*) LDFLAGS=${arg#*=} ;;
*=*) ;;
*) ;;
esac
done

for i in SRCDIR PREFIX EXEC_PREFIX BINDIR SHAREDIR MANDIR ; do
stripdir $i
done

#
# Get the source dir for out-of-tree builds
#
if test -z "$SRCDIR" ; then
SRCDIR="${0%/configure}"
stripdir SRCDIR
fi
abs_builddir="$(pwd)" || fail "$0: cannot determine working directory"
abs_srcdir="$(cd $SRCDIR && pwd)" || fail "$0: invalid source directory $SRCDIR"
test "$abs_srcdir" = "$abs_builddir" && SRCDIR=.
test "$SRCDIR" != "." -a -f Makefile -a ! -h Makefile && fail "$0: Makefile already exists in the working directory"

#
# Get a temp filename we can use
#
i=0
set -C
while : ; do i=$(($i+1))
tmpc="./conf$$-$PPID-$i.c"
tmpo="./conf$$-$PPID-$i.o"
2>|/dev/null > "$tmpc" && break
test "$i" -gt 50 && fail "$0: cannot create temporary file $tmpc"
done
set +C
trap 'rm -f "$tmpc" "$tmpo"' EXIT INT QUIT TERM HUP

#
# Find a C compiler to use
#
printf "checking for C compiler... "
trycc cc
trycc gcc
trycc clang
printf "%s\n" "$CC"
test -n "$CC" || { echo "$0: cannot find a C compiler" ; exit 1 ; }

printf "checking whether C compiler works... "
echo "typedef int x;" > "$tmpc"
if output=$($CC $CPPFLAGS $CFLAGS -c -o "$tmpo" "$tmpc" 2>&1) ; then
printf "yes\n"
else
printf "no; compiler output follows:\n%s\n" "$output"
exit 1
fi

#
# Figure out options to force errors on unknown flags.
#
tryflag   CFLAGS_TRY  -Werror=unknown-warning-option
tryflag   CFLAGS_TRY  -Werror=unused-command-line-argument
tryldflag LDFLAGS_TRY -Werror=unknown-warning-option
tryldflag LDFLAGS_TRY -Werror=unused-command-line-argument

CFLAGS_STD="-std=c99 -D_POSIX_C_SOURCE=200809L -D_XOPEN_SOURCE=700 -DNDEBUG -D_FORTIFY_SOURCE=2"
LDFLAGS_STD="-lc"

OS=$(uname)

case "$OS" in
*BSD)   CFLAGS_STD="$CFLAGS_STD -D_BSD_SOURCE" ;;
Darwin) CFLAGS_STD="$CFLAGS_STD -D_DARWIN_C_SOURCE" ;;
AIX)    CFLAGS_STD="$CFLAGS_STD -D_ALL_SOURCE" ;;
esac

tryflag CFLAGS -pipe

# Try flags to optimize binary size
tryflag CFLAGS -Os
#tryflag CFLAGS -ffunction-sections
#tryflag CFLAGS -fdata-sections
#tryldflag LDFLAGS_AUTO -Wl,--gc-sections

# Try hardening flags
tryflag CFLAGS -fPIE
tryflag CFLAGS_AUTO -fstack-protector-all
tryldflag LDFLAGS -Wl,-z,now
tryldflag LDFLAGS -Wl,-z,relro
# in theory it should be perfectly fine to produce a staticically linked PIE
# however in practice it is not yet properly supported by gcc:
#
#  cc -fPIE -pie --static
#
# will always add a PT_INTERP referencing the dynamic loader/linker
if test "$static" != "yes" || tryldflag LDFLAGS_AUTO -Wl,--no-dynamic-linker ; then
	tryldflag LDFLAGS_AUTO -pie
fi

printf "creating config.mk... "

cmdline=$(quote "$0")
for i ; do cmdline="$cmdline $(quote "$i")" ; done

exec 3>&1 1>config.mk

cat << EOF
# This version of config.mk was generated by:
# $cmdline
# Any changes made here will be lost if configure is re-run
SRCDIR = $SRCDIR
PREFIX = $PREFIX
EXEC_PREFIX = $EXEC_PREFIX
BINDIR = $BINDIR
MANPREFIX = $MANDIR
SHAREPREFIX = $SHAREDIR
CC = $CC
CFLAGS = $CFLAGS
LDFLAGS = $LDFLAGS
CFLAGS_STD = $CFLAGS_STD
LDFLAGS_STD = $LDFLAGS_STD
CFLAGS_AUTO = $CFLAGS_AUTO
LDFLAGS_AUTO = $LDFLAGS_AUTO
EOF
exec 1>&3 3>&-

printf "done\n"

if test "$environmentonly" = "yes"; then
	exit 0
fi

have_pkgconfig=no
printf "checking for pkg-config... "
cmdexists pkg-config && have_pkgconfig=yes
printf "%s\n" "$have_pkgconfig"

# libcurses is a mandatory dependency

printf "checking for libcurses...\n"
cat > "$tmpc" <<EOF
#include <curses.h>

int main(int argc, char *argv[]) {
	initscr();
	endwin();
	return 0;
}
EOF

CONFIG_CURSES=0

for curses in ncursesw ncurses curses; do
	printf " checking for %s... " "$curses"

	if test "$have_pkgconfig" = "yes" ; then
		CFLAGS_CURSES=$(pkg-config --cflags $curses 2>/dev/null)
		LDFLAGS_CURSES=$(pkg-config --libs $curses 2>/dev/null)
		if test $? -eq 0 && $CC $CFLAGS $CFLAGS_CURSES "$tmpc" \
			$LDFLAGS $LDFLAGS_CURSES -o "$tmpo" >/dev/null 2>&1 ; then
			CONFIG_CURSES=1
			printf "yes\n"
			break
		fi
	fi

	CFLAGS_CURSES=""
	LDFLAGS_CURSES="-l$curses"

	if $CC $CFLAGS $CFLAGS_CURSES "$tmpc" \
		$LDFLAGS $LDFLAGS_CURSES -o "$tmpo" >/dev/null 2>&1 ; then
		CONFIG_CURSES=1
		printf "yes\n"
		break
	else
		printf "no\n"
	fi
done

test $CONFIG_CURSES -ne 1 && fail "$0: cannot find libcurses"

# libtermkey is a mandatory dependency

printf "checking for libtermkey... "
cat > "$tmpc" <<EOF
#include <termkey.h>

int main(int argc, char *argv[]) {
	TERMKEY_CHECK_VERSION;
	return 0;
}
EOF

if test "$have_pkgconfig" = "yes" ; then
	CFLAGS_TERMKEY=$(pkg-config --cflags termkey 2>/dev/null)
	LDFLAGS_TERMKEY=$(pkg-config --libs termkey 2>/dev/null)
fi

if test -z "$LDFLAGS_TERMKEY"; then
	CFLAGS_TERMKEY=""
	LDFLAGS_TERMKEY="-ltermkey"
fi

if $CC $CFLAGS $CFLAGS_TERMKEY "$tmpc" $LDFLAGS $LDFLAGS_TERMKEY $LDFLAGS_CURSES \
	-o "$tmpo" >/dev/null 2>&1; then
	printf "%s\n" "yes"
else
	printf "%s\n" "no"
	fail "$0: cannot find libtermkey"
fi

CONFIG_LUA=0

if test "$lua" != "no" ; then

	printf "checking for liblua...\n"

cat > "$tmpc" <<EOF
#include <lua.h>
#include <lauxlib.h>

int main(int argc, char *argv[]) {
	lua_State *L = luaL_newstate();
	luaL_openlibs(L);
	lua_close(L);
	return 0;
}
EOF

	for liblua in lua lua5.2 lua5.3 lua-5.2 lua-5.3 lua52 lua53; do
		printf " checking for %s... " "$liblua"

		if test "$have_pkgconfig" = "yes" ; then
			CFLAGS_LUA=$(pkg-config --cflags $liblua 2>/dev/null)
			LDFLAGS_LUA=$(pkg-config --libs $liblua 2>/dev/null)
			if test $? -eq 0 && $CC $CFLAGS $CFLAGS_LUA "$tmpc" \
				$LDFLAGS $LDFLAGS_LUA -o "$tmpo" >/dev/null 2>&1 ; then
				CONFIG_LUA=1
				printf "yes\n"
				break
			fi
		fi

		CFLAGS_LUA=""
		LDFLAGS_LUA="-l$liblua -lm -ldl"

		if $CC $CFLAGS $CFLAGS_LUA "$tmpc" \
			$LDFLAGS $LDFLAGS_LUA -o "$tmpo" >/dev/null 2>&1 ; then
			CONFIG_LUA=1
			printf "yes\n"
			break
		else
			printf "no\n"
			CFLAGS_LUA=""
			LDFLAGS_LUA=""
		fi
	done

	test "$lua" = "yes" -a $CONFIG_LUA -ne 1 && fail "$0: cannot find liblua"

	if test $CONFIG_LUA -eq 1; then
		CFLAGS_LUA="$CFLAGS_LUA -DLUA_COMPAT_5_1 -DLUA_COMPAT_5_2 -DLUA_COMPAT_ALL"
	fi
fi

CONFIG_ACL=0

if test "$OS" = "Linux" -a "$acl" != "no"; then
	printf "checking for libacl... "

cat > "$tmpc" <<EOF
#include <sys/types.h>
#include <sys/acl.h>

int main(int argc, char *argv[]) {
	acl_t acl = acl_get_fd(0);
	return 0;
}
EOF

	if test "$have_pkgconfig" = "yes" ; then
		CFLAGS_ACL=$(pkg-config --cflags acl 2>/dev/null)
		LDFLAGS_ACL=$(pkg-config --libs acl 2>/dev/null)
	fi

	if test -z "$LDFLAGS_ACL"; then
		CFLAGS_ACL=""
		LDFLAGS_ACL="-lacl"
	fi

	if $CC $CFLAGS $CFLAGS_ACL "$tmpc" \
		$LDFLAGS $LDFLAGS_ACL -o "$tmpo" >/dev/null 2>&1; then
		CONFIG_ACL=1
		printf "%s\n" "yes"
	else
		printf "%s\n" "no"
		CFLAGS_ACL=""
		LDFLAGS_ACL=""
		test "$acl" = "yes" && fail "$0: cannot find libacl"
	fi
fi

CONFIG_SELINUX=0

if test "$OS" = "Linux" -a "$selinux" != "no"; then
	printf "checking for libselinux... "

cat > "$tmpc" <<EOF
#include <selinux/selinux.h>

int main(int argc, char *argv[]) {
	return is_selinux_enabled();
}
EOF

	if test "$have_pkgconfig" = "yes" ; then
		CFLAGS_SELINUX=$(pkg-config --cflags selinux 2>/dev/null)
		LDFLAGS_SELINUX=$(pkg-config --libs selinux 2>/dev/null)
	fi

	if test -z "$LDFLAGS_SELINUX"; then
		CFLAGS_SELINUX=""
		LDFLAGS_SELINUX="-lselinux"
	fi

	if $CC $CFLAGS $CFLAGS_SELINUX "$tmpc" \
		$LDFLAGS $LDFLAGS_SELINUX -o "$tmpo" >/dev/null 2>&1; then
		CONFIG_SELINUX=1
		printf "%s\n" "yes"
	else
		printf "%s\n" "no"
		CFLAGS_SELINUX=""
		LDFLAGS_SELINUX=""
		test "$selinux" = "yes" && fail "$0: cannot find libselinux"
	fi
fi

printf "completing config.mk... "

exec 3>&1 1>>config.mk

cat << EOF
CFLAGS_CURSES = $CFLAGS_CURSES
LDFLAGS_CURSES = $LDFLAGS_CURSES
CFLAGS_TERMKEY = $CFLAGS_TERMKEY
LDFLAGS_TERMKEY = $LDFLAGS_TERMKEY
CONFIG_LUA = $CONFIG_LUA
CFLAGS_LUA = $CFLAGS_LUA
LDFLAGS_LUA = $LDFLAGS_LUA
CONFIG_ACL = $CONFIG_ACL
CFLAGS_ACL = $CFLAGS_ACL
LDFLAGS_ACL = $LDFLAGS_ACL
CONFIG_SELINUX = $CONFIG_SELINUX
CFLAGS_SELINUX = $CFLAGS_SELINUX
LDFLAGS_SELINUX = $LDFLAGS_SELINUX
EOF
exec 1>&3 3>&-

test "$SRCDIR" = "." || ln -sf $SRCDIR/Makefile .

printf "done\n"