libsys: plumb in to build

libsys provides the FreeBSD kernel interface (auxargs, system calls,
vdso).  It can be linked directly for programs using a non-standard
libc and will later be linked as a filter library to libc providing
the actual system call implementation.

Reviewed by:	kib, emaste, imp
Pull Request:	https://github.com/freebsd/freebsd-src/pull/908

lib/Makefile

@@ -19,6 +19,7 @@ SUBDIR_BOOTSTRAP= \
 	libelf \
 	libssp \
 	libssp_nonshared \
+	libsys \
 	msun
 
 # The main list; please keep these sorted alphabetically.
@@ -137,6 +138,8 @@ SUBDIR_DEPEND_libpjdlog= libutil
 SUBDIR_DEPEND_libprocstat= libkvm libutil
 SUBDIR_DEPEND_libradius= libmd
 SUBDIR_DEPEND_libsmb= libkiconv
+# See comment above about libssp_nonshared
+SUBDIR_DEPEND_libsys= libcompiler_rt libssp_nonshared
 SUBDIR_DEPEND_libtacplus= libmd
 SUBDIR_DEPEND_libulog= libmd
 SUBDIR_DEPEND_libunbound= ${_libldns}

lib/libsys/Makefile

@@ -0,0 +1,73 @@
+PACKAGE=	clibs
+SHLIBDIR?= /lib
+
+.include <src.opts.mk>
+
+LIBC_SRCTOP?= ${.CURDIR}/../libc
+LIBSYS_SRCTOP?=	${.CURDIR}
+
+# Pick the current architecture directory for libsys. In general, this is named
+# MACHINE_CPUARCH, but some ABIs are different enough to require their own
+# libsys, so allow a directory named MACHINE_ARCH to override this (though
+# treat powerpc64le and powerpc64 the same).
+# Note: This is copied from libc/Makefile
+M=${MACHINE_ARCH:S/powerpc64le/powerpc64/}
+.if exists(${LIBC_SRCTOP}/${M})
+LIBC_ARCH=${M}
+.else
+LIBC_ARCH=${MACHINE_CPUARCH}
+.endif
+
+LIB=sys
+SHLIB_MAJOR= 7
+WARNS?=	2
+
+CFLAGS+=-I${LIBSYS_SRCTOP}/include -I${LIBC_SRCTOP}/include
+CFLAGS+=-I${LIBSYS_SRCTOP}/${LIBC_ARCH}
+CFLAGS+=-I${LIBC_SRCTOP}/${LIBC_ARCH}
+
+CLEANFILES+=tags
+INSTALL_PIC_ARCHIVE=
+#XXX? BUILD_NOSSP_PIC_ARCHIVE=
+PRECIOUSLIB=
+
+# Use a more efficient TLS model for libc since we can reasonably assume that
+# it will be loaded during program startup.
+CFLAGS+= -ftls-model=initial-exec
+
+#
+# Link with static libcompiler_rt.a.
+#
+LDFLAGS+= -nodefaultlibs
+LIBADD+=	compiler_rt
+
+.if ${MK_SSP} != "no" && \
+    (${LIBC_ARCH} == "i386" || ${LIBC_ARCH:Mpowerpc*} != "")
+LIBADD+=        ssp_nonshared
+.endif
+
+#.if ${MK_SSP} != "no" && \
+#    (${LIBC_ARCH} == "i386" || ${LIBC_ARCH:Mpowerpc*} != "")
+#LIBADD+=	ssp_nonshared
+#.endif
+
+# Define (empty) variables so that make doesn't give substitution
+# errors if the included makefiles don't change these:
+MDASM=
+MIASM=
+NOASM=
+
+.include "${LIBSYS_SRCTOP}/Makefile.sys"
+
+VERSION_DEF=${LIBC_SRCTOP}/Versions.def
+SYMBOL_MAPS=${SYM_MAPS}
+
+# XXX: let libc install the manpages for now
+MAN=
+MLINKS=
+
+# XXX: move sys tests?
+#HAS_TESTS=
+#SUBDIR.${MK_TESTS}+= tests
+
+.include <bsd.lib.mk>

lib/libsys/Makefile.sys

@@ -158,6 +158,7 @@ ${SPSEUDO}:
 	printf ${NOTE_GNU_STACK} >>${.TARGET}
 	printf ${FEATURE_NOTE} >> ${.TARGET}
 
+.if ${LIB} == "sys"
 MAN+=	abort2.2 \
 	accept.2 \
 	access.2 \
@@ -541,3 +542,4 @@ MLINKS+=wait.2 wait3.2 \
 MLINKS+=write.2 pwrite.2 \
 	write.2 pwritev.2 \
 	write.2 writev.2
+.endif # ${LIB} == "sys"

share/mk/src.libnames.mk

@@ -202,6 +202,7 @@ _LIBRARIES=	\
 		stats \
 		stdthreads \
 		supcplusplus \
+		sys \
 		sysdecode \
 		tacplus \
 		termcapw \
@@ -401,6 +402,13 @@ _DP_c+=		ssp_nonshared
 .endif
 _DP_stats=	sbuf pthread
 _DP_stdthreads=	pthread
+_DP_sys=	compiler_rt
+# Use libssp_nonshared only on i386 and power*.  Other archs emit direct calls
+# to __stack_chk_fail, not __stack_chk_fail_local provided by libssp_nonshared.
+.if ${MK_SSP} != "no" && \
+    (${MACHINE_ARCH} == "i386" || ${MACHINE_ARCH:Mpower*} != "")
+_DP_sys+=	ssp_nonshared
+.endif
 _DP_tacplus=	md pam
 _DP_ncursesw=	tinfow
 _DP_formw=	ncursesw
@@ -554,6 +562,9 @@ LIBSMDB?=	${LIBSMDBDIR}/libsmdb${PIE_SUFFIX}.a
 LIBSMUTILDIR=	${_LIB_OBJTOP}/lib/libsmutil
 LIBSMUTIL?=	${LIBSMUTILDIR}/libsmutil${PIE_SUFFIX}.a
 
+LIBSYSDIR=	${_LIB_OBJTOP}/lib/libsys
+LIBSYS?=	${LIBSYSDIR}/libsys${PIE_SUFFIX}.a
+
 LIBNETBSDDIR?=	${_LIB_OBJTOP}/lib/libnetbsd
 LIBNETBSD?=	${LIBNETBSDDIR}/libnetbsd${PIE_SUFFIX}.a