[2/5] misc: enable UBSAN if the builder wants it

diff --git a/MCONFIG.in b/MCONFIG.in
index f06933d..4234ff0 100644
--- a/MCONFIG.in
+++ b/MCONFIG.in
@@ -81,8 +81,8 @@  SYSTEMD_SYSTEM_UNIT_DIR = @systemd_system_unit_dir@
 @ifNotGNUmake@ CHECK_CMD=true
 @ifNotGNUmake@ CPPCHECK_CMD=true
 
-SANITIZER_CFLAGS = @lto_cflags@
-SANITIZER_LDFLAGS = @lto_ldflags@
+SANITIZER_CFLAGS = @lto_cflags@ @ubsan_cflags@
+SANITIZER_LDFLAGS = @lto_ldflags@ @ubsan_ldflags@
 
 CC = @CC@
 BUILD_CC = @BUILD_CC@
diff --git a/config/ltmain.sh b/config/ltmain.sh
new file mode 120000
index 0000000..8cff389
--- /dev/null
+++ b/config/ltmain.sh
@@ -0,0 +1 @@ 
+/usr/share/libtool/build-aux/ltmain.sh
\ No newline at end of file
diff --git a/configure b/configure
index 5947614..7632a4a 100755
--- a/configure
+++ b/configure
@@ -653,6 +653,9 @@  E2SCRUB_CMT
 UNIX_CMT
 CYGWIN_CMT
 LINUX_CMT
+ubsan_ldflags
+ubsan_cflags
+have_ubsan
 lto_ldflags
 lto_cflags
 have_lto
@@ -909,6 +912,7 @@  with_included_gettext
 with_libintl_prefix
 enable_fuse2fs
 enable_lto
+enable_ubsan
 with_multiarch
 with_udev_rules_dir
 with_crond_dir
@@ -1588,6 +1592,7 @@  Optional Features:
   --disable-rpath         do not hardcode runtime library paths
   --disable-fuse2fs	  do not build fuse2fs
   --enable-lto		  enable link time optimization
+  --enable-ubsan	  enable undefined behavior sanitizer
 
 Optional Packages:
   --with-PACKAGE[=ARG]    use PACKAGE [ARG=yes]
@@ -13865,6 +13870,53 @@  fi
 if test "$enable_lto" = "yes" && test "$have_lto" != "yes"; then
 	as_fn_error $? "LTO not supported by compiler." "$LINENO" 5
 fi
+# Check whether --enable-ubsan was given.
+if test "${enable_ubsan+set}" = set; then :
+  enableval=$enable_ubsan;
+else
+  enable_ubsan=no
+fi
+
+if test "$enable_ubsan" = "yes" || test "$enable_ubsan" = "probe"; then
+	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking if C compiler supports UBSAN" >&5
+$as_echo_n "checking if C compiler supports UBSAN... " >&6; }
+	OLD_CFLAGS="$CFLAGS"
+	OLD_LDFLAGS="$LDFLAGS"
+	UBSAN_FLAGS="-fsanitize=undefined"
+	CFLAGS="$CFLAGS $UBSAN_FLAGS"
+	LDFLAGS="$LDFLAGS $UBSAN_FLAGS"
+	cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+		ubsan_cflags=$UBSAN_FLAGS
+		ubsan_ldflags=$UBSAN_FLAGS
+		have_ubsan=yes
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+	CFLAGS="${OLD_CFLAGS}"
+	LDFLAGS="${OLD_LDFLAGS}"
+
+
+
+fi
+if test "$enable_ubsan" = "yes" && test "$have_ubsan" != "yes"; then
+	as_fn_error $? "UBSAN not supported by compiler." "$LINENO" 5
+fi
 LINUX_CMT="#"
 CYGWIN_CMT="#"
 UNIX_CMT=
diff --git a/configure.ac b/configure.ac
index a605aad..981c6b0 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1329,6 +1329,34 @@  if test "$enable_lto" = "yes" && test "$have_lto" != "yes"; then
 	AC_MSG_ERROR([LTO not supported by compiler.])
 fi
 dnl
+dnl Enable UBSAN for all packages
+dnl
+AC_ARG_ENABLE([ubsan],
+[  --enable-ubsan	  enable undefined behavior sanitizer],,
+enable_ubsan=no)
+if test "$enable_ubsan" = "yes" || test "$enable_ubsan" = "probe"; then
+	AC_MSG_CHECKING([if C compiler supports UBSAN])
+	OLD_CFLAGS="$CFLAGS"
+	OLD_LDFLAGS="$LDFLAGS"
+	UBSAN_FLAGS="-fsanitize=undefined"
+	CFLAGS="$CFLAGS $UBSAN_FLAGS"
+	LDFLAGS="$LDFLAGS $UBSAN_FLAGS"
+	AC_LINK_IFELSE([AC_LANG_PROGRAM([])],
+		[AC_MSG_RESULT([yes])]
+		[ubsan_cflags=$UBSAN_FLAGS]
+		[ubsan_ldflags=$UBSAN_FLAGS]
+		[have_ubsan=yes],
+		[AC_MSG_RESULT([no])])
+	CFLAGS="${OLD_CFLAGS}"
+	LDFLAGS="${OLD_LDFLAGS}"
+	AC_SUBST(have_ubsan)
+	AC_SUBST(ubsan_cflags)
+	AC_SUBST(ubsan_ldflags)
+fi
+if test "$enable_ubsan" = "yes" && test "$have_ubsan" != "yes"; then
+	AC_MSG_ERROR([UBSAN not supported by compiler.])
+fi
+dnl
 dnl OS-specific uncomment control
 dnl
 LINUX_CMT="#"
diff --git a/debian/rules b/debian/rules
index 176ea78..600b751 100755
--- a/debian/rules
+++ b/debian/rules
@@ -164,7 +164,7 @@  endif
 
 BACKTRACE_CONF_FLAGS ?= $(shell if ${debdir}/scripts/test-backtrace ; then echo --disable-backtrace ; fi)
 
-COMMON_CONF_FLAGS = --enable-lto --disable-e2initrd-helper \
+COMMON_CONF_FLAGS = --enable-lto --disable-ubsan --disable-e2initrd-helper \
 	--infodir=/usr/share/info  --enable-symlink-install \
 	--with-multiarch=$(DEB_HOST_MULTIARCH) \
 	$(BACKTRACE_CONF_FLAGS) $(UTIL_CONF_FLAGS)