##############################################################################
# 1. Initialize the autoconf build
##############################################################################

# Process this file with autoconf to produce a configure script.
AC_INIT([torsocks], [2.3.0],[dgoulet@torproject.org],[],[https://torproject.org])
AC_CONFIG_AUX_DIR([config])
AC_CANONICAL_TARGET
# Get hostname and other information.
AC_CANONICAL_HOST
AC_CONFIG_MACRO_DIR([config])

# Create a config.h file to store defines generated by configure
AC_CONFIG_HEADER([include/config.h])

# Try to enable the POSIX extensions.
AC_USE_SYSTEM_EXTENSIONS

# Automake initialization
AM_INIT_AUTOMAKE([foreign dist-xz no-dist-gzip])

# Silent compilation. Easier to spot errors!
m4_ifdef([AM_SILENT_RULES], [AM_SILENT_RULES([yes])])

dnl Checks for programs.
AC_PROG_CC
AC_PROG_INSTALL
AC_PROG_LN_S

##############################################################################
# 2. Check for some standard headers and libraries
##############################################################################

dnl Check if the C compiler accepts -Wall
AC_MSG_CHECKING(if the C compiler accepts -Wall)
OLDCFLAGS="$CFLAGS"
CFLAGS="$CFLAGS -Wall"
AC_TRY_COMPILE(,,
	[AC_MSG_RESULT(yes)],
	[
		CFLAGS="$OLDCFLAGS"
		AC_MSG_RESULT(no)
	]
)

dnl Checks for standard header files.
AC_HEADER_STDC

AC_CHECK_HEADERS(dlfcn.h sys/syscall.h sys/socket.h arpa/inet.h \
                 assert.h netdb.h errno.h stdarg.h time.h,,
	[AC_MSG_ERROR("Required header not found")]
)

dnl Checks for required library functions.
AC_CHECK_FUNCS(strcspn strdup strerror strcasecmp strncasecmp mmap munmap \
               socket connect close syscall recv send memset memcpy strlen \
               strncpy strcmp malloc calloc strstr strtoul free,,
	[AC_MSG_ERROR("Required function not found")]
)

##############################################################################
# 3. Determine libraries we need to include when linking libtorsocks.
#    OpenBSD and OSX have some special requirements here.
#    Also check the host we're building on, as some of the code
#    in torsocks.c and elsewhere is platform-dependent.
##############################################################################

dnl Check for a function to convert an ascii ip address
dnl to a sin_addr.
AC_CHECK_FUNC(inet_aton, AC_DEFINE([HAVE_INET_ATON],[],[Description]),
	[AC_CHECK_FUNC(inet_addr, AC_DEFINE([HAVE_INET_ADDR],[],[Description]),
		[AC_CHECK_LIB(nsl, inet_addr,
			[
				AC_DEFINE([HAVE_INET_ADDR],[],[Description])
				LIBS="${LIBS} -lnsl"
			],
			[AC_MSG_ERROR("Neither inet_aton or inet_addr present")]
		)]
	)]
)

dnl Look for gethostbyname (needed by torsocks)
AC_CHECK_FUNC(gethostbyname, AC_DEFINE([HAVE_GETHOSTBYNAME],[],[Description]),
	[AC_CHECK_LIB(xnet, gethostbyname, AC_DEFINE([HAVE_GETHOSTBYNAME],[],[Description]),
		[AC_MSG_ERROR(["gethostbyname not found, name lookups in torsocks disabled"])]
	)]
)

dnl Do we have dlopen(3) in libdl?
AC_SEARCH_LIBS([dlopen], [dl],,
	[AC_MSG_ERROR("dlopen function not found in libdl")]
)

dnl OpenBSD needs -lpthread. It also doesn't support AI_V4MAPPED.
case $host in
*-*-openbsd*)
	AC_DEFINE(OPENBSD, 1, "Define to handle OpenBSD")
	AC_SEARCH_LIBS(pthread_create, [pthread])
	;;
*-*-freebsd*)
	AC_DEFINE(FREEBSD, 1, "Define to handle FreeBSD")
	;;
*-*-darwin*)
	dnl Needed to compile tests.
	dnl See https://bugs.g10code.com/gnupg/issue1292:
	dnl "On OS X (at least in 10.6 and I believe starting at 10.3) the DNS resolution
	dnl services fail to compile.  This is a result of the addition of BIND9 compatible
	dnl resolution libraries on OS X that are being picked up by the configure script
	dnl instead of -lresolv causing the tests for useable resolution services to fail
	dnl thus disabling features like pka auto lookup."
	LIBS="-lresolv $LIBS"
	;;
esac

if test "x${enable_envconf}" = "x"; then
	AC_DEFINE([ALLOW_ENV_CONFIG],[],[Description])
fi

dnl Get libc full system path. Use prefix or some hardcoded standard
dnl location on Unixish system.
AC_MSG_CHECKING(file name of the C library)
AS_CASE([$host_os],
	[darwin*], [libc_name="libSystem.dylib"],
	[linux*|kfreebsd*-gnu|freebsd*],
	[
		libc_name=`ldd /usr/bin/yes | grep 'libc\.' | cut -d ' ' -f 1 | tr -d '\t'`
		if test "${libc_name}" == ""; then
			# Default libc on most system.
			libc_name="libc.so.6"
		fi
	],
	[libc_name="libc.so"]
)
AC_DEFINE_UNQUOTED([LIBC_NAME],["${libc_name}"], [Description])
AC_MSG_RESULT($libc_name)

##############################################################################
# 5. Determine how to preload libtorsocks.so on this system.
#    On Linux this is with the LD_PRELOAD variable, on OSX
#    we need to use DYLD_INSERT_LIBRARIES.
##############################################################################

# This variable is used for the LDFLAGS in test/Makefile.am
TESTLDFLAGS="$LDFLAGS"
AC_SUBST(TESTLDFLAGS)

# Version information for libtorsocks
TORSOCKSLDFLAGS="$LDFLAGS -version-info 1:0:0"

dnl Linker checks for Mac OSX, which uses DYLD_INSERT_LIBRARIES
dnl instead of LD_PRELOAD
case "$host_os" in
darwin*)
    dnl Check if the linker accepts -dynamiclib; necessary on Mac OS X
    AC_MSG_CHECKING(if the linker accepts -dynamiclib)
    OLDLDFLAGS="$TORSOCKSLDFLAGS"
    TORSOCKSLDFLAGS="$TORSOCKSLDFLAGS -dynamiclib"
    AC_TRY_COMPILE(,, [AC_MSG_RESULT(yes)],
		[
			TORSOCKSLDFLAGS="$OLDLDFLAGS"
			AC_MSG_RESULT(no)
		]
	)

    # dnl Check if the linker accepts -multiply_defined suppress; necessary on Mac OS X
    # AC_MSG_CHECKING(if the linker accepts -multiply_defined suppress)
    # OLDLDFLAGS="$LDFLAGS"
    # LDFLAGS="$LDFLAGS -multiply_defined suppress"
    # AC_TRY_COMPILE(,,AC_MSG_RESULT(yes),[
    #    LDFLAGS="$OLDLDFLAGS"
    #    AC_MSG_RESULT(no)])

    dnl Check if the linker accepts -single_module; necessary on Mac OS X
    AC_MSG_CHECKING(if the linker accepts -single_module)
    OLDLDFLAGS="$TORSOCKSLDFLAGS"
    SHLIB_EXT="so"
    LDPRELOAD="LD_PRELOAD"
    TORSOCKSLDFLAGS="$TORSOCKSLDFLAGS -single_module"
    AC_TRY_COMPILE(,,
		[
			SHLIB_EXT="dylib"
			LDPRELOAD="DYLD_INSERT_LIBRARIES"
			AC_MSG_RESULT(yes)
		],
		[
			TORSOCKSLDFLAGS="$OLDLDFLAGS"
			AC_MSG_RESULT(no)
		]
    )
    ;;
*)
    SHLIB_EXT="so"
    LDPRELOAD="LD_PRELOAD"
    ;;
esac

AC_SUBST(SHLIB_EXT)
AC_SUBST(LDPRELOAD)
AC_SUBST(TORSOCKSLDFLAGS)

##############################################################################
# 7. Determine where the install should write the default configuration
#    file and where libtorsocks should read it from by default.
##############################################################################

if test "x$prefix" = "xNONE"; then
  prefix=$ac_default_prefix
fi

if test "x$CONFDIR" = "x"; then
  CONFDIR=`eval echo $sysconfdir`
fi
AC_SUBST(CONFDIR)
AH_TEMPLATE([CONFDIR],[torsocks configuration directory])
AC_DEFINE_UNQUOTED(CONFDIR,"$CONFDIR")

AC_ARG_WITH(conf,
[  --with-conf=<file>      location of configuration file (${CONFDIR}/torsocks.conf default)],[
if test "${withval}" = "yes" ; then
  AC_MSG_ERROR("--with-conf requires the location of the configuration file as an argument")
else
  AC_DEFINE_UNQUOTED([CONF_FILE], ["${withval}"],[Description])
fi
], [
  AC_DEFINE_UNQUOTED([CONF_FILE], ["${CONFDIR}/torsocks.conf"],[Description])
])

##############################################################################
# 8. Clean up and create some supporting scripts from their *.in files
##############################################################################

AC_LANG_C
AC_PROG_CC
AC_LIBTOOL_DLOPEN
AC_PROG_LIBTOOL
AC_SUBST(LIBTOOL_DEPS)
AC_ENABLE_SHARED
AC_ENABLE_STATIC

DEFAULT_INCLUDES="-I\$(top_srcdir) -I\$(top_builddir) -I\$(top_builddir)/src -I\$(top_builddir)/include -include config.h"
AC_SUBST(DEFAULT_INCLUDES)

##############################################################################
# 9. Test and add hardening flags
##############################################################################

# Check for the gcc hardening flags.
AX_CHECK_COMPILE_FLAG([-fPIE],[CFLAGS="$CFLAGS -fPIE"],[],[])
AX_CHECK_COMPILE_FLAG([-fwrapv],[CFLAGS="$CFLAGS -fwrapv"],[],[])
AX_CHECK_COMPILE_FLAG([--param ssp-buffer-size=1],
	[CFLAGS="$CFLAGS --param ssp-buffer-size=1"],[],[])
AX_CHECK_COMPILE_FLAG([-fstack-protector-all],
	[CFLAGS="$CFLAGS -fstack-protector-all"],[],[]
)

dnl Add hardening linker flags
AX_CHECK_LINK_FLAG([-pie],[LDFLAGS="$LDFLAGS -pie"],[],[])
AX_CHECK_LINK_FLAG([-z relro],[LDFLAGS="$LDFLAGS -z relro"],[],[])
AX_CHECK_LINK_FLAG([-z now],[LDFLAGS="$LDFLAGS -z now"],[],[])

dnl Add glibc hardening
CPPFLAGS="$CPPFLAGS -D_FORTIFY_SOURCE=2"

##############################################################################
# 10. Finish up
##############################################################################

AC_CONFIG_FILES([
	Makefile
	extras/Makefile
	src/Makefile
	src/bin/Makefile
	src/bin/torsocks
	src/common/Makefile
	src/lib/Makefile
	tests/Makefile
	tests/unit/Makefile
	tests/utils/Makefile
	tests/utils/tap/Makefile
	doc/Makefile
])

AC_OUTPUT