ostree-prepare-root: Allow building statically with musl

If the `--with-static-compiler=musl-gcc` configure flag is given.

ostree-prepare-root can be used as init in a system without a populated
/lib.  To support this use case we need to link statically as we will be
unable to locate libc.so at run time if it's not installed in /lib.

We support building ostree-prepare-root with a different compiler to the
rest of ostree so we can use musl rather than glibc.  This reduces the size
of the executable significantly: from ~700K -> ~30K.  We have to use
`_SCRIPTS` here to get autotools to install this as an executable but
without generating rules to make it itself which we have specified
manually.

See https://lists.gnu.org/archive/html/help-gnu-utils/2007-01/msg00007.html
for advice on using autotools in this manner.

Closes: #477
Approved by: cgwalters
This commit is contained in:
William Manley 2016-08-30 20:28:02 +01:00 committed by Atomic Bot
parent faee3df8ae
commit 42dab85728
2 changed files with 34 additions and 4 deletions

View File

@ -17,7 +17,6 @@
if BUILDOPT_SYSTEMD if BUILDOPT_SYSTEMD
ostree_boot_PROGRAMS += ostree-prepare-root
ostree_boot_PROGRAMS += ostree-remount ostree_boot_PROGRAMS += ostree-remount
noinst_LTLIBRARIES += libswitchroot-mountutil.la noinst_LTLIBRARIES += libswitchroot-mountutil.la
@ -28,9 +27,32 @@ libswitchroot_mountutil_la_SOURCES = \
src/switchroot/ostree-mount-util.h \ src/switchroot/ostree-mount-util.h \
$(NULL) $(NULL)
ostree_prepare_root_SOURCES = src/switchroot/ostree-prepare-root.c ostree_prepare_root_SOURCES = \
ostree_prepare_root_LDADD = libswitchroot-mountutil.la src/switchroot/ostree-mount-util.c \
src/switchroot/ostree-mount-util.h \
src/switchroot/ostree-prepare-root.c \
$(NULL)
if BUILDOPT_USE_STATIC_COMPILER
# ostree-prepare-root can be used as init in a system without a populated /lib.
# To support this use case we need to link statically as we will be unable to
# locate libc.so at run time if it's not installed in /lib.
#
# We support building ostree-prepare-root with a different compiler to the rest
# of ostree so we can use musl rather than glibc. This reduces the size of the
# executable significantly: from ~700K -> ~30K. We have to use _SCRIPTS here
# to get autotools to install this as an executable but without generating rules
# to make it itself which we have specified manually. See
# https://lists.gnu.org/archive/html/help-gnu-utils/2007-01/msg00007.html
ostree_boot_SCRIPTS = ostree-prepare-root
ostree-prepare-root : $(ostree_prepare_root_SOURCES)
$(STATIC_COMPILER) -o $@ -static $(ostree_prepare_root_SOURCES) $(AM_CPPFLAGS) $(AM_CFLAGS)
else
ostree_boot_PROGRAMS += ostree-prepare-root
ostree_prepare_root_CFLAGS = $(AM_CFLAGS) -Isrc/switchroot ostree_prepare_root_CFLAGS = $(AM_CFLAGS) -Isrc/switchroot
endif
ostree_remount_SOURCES = src/switchroot/ostree-remount.c ostree_remount_SOURCES = src/switchroot/ostree-remount.c
ostree_remount_LDADD = libswitchroot-mountutil.la ostree_remount_LDADD = libswitchroot-mountutil.la

View File

@ -295,6 +295,13 @@ AS_IF([test x$with_grub2_mkconfig_path = x], [
],[GRUB2_MKCONFIG=$with_grub2_mkconfig_path]) ],[GRUB2_MKCONFIG=$with_grub2_mkconfig_path])
AC_DEFINE_UNQUOTED([GRUB2_MKCONFIG_PATH], ["$GRUB2_MKCONFIG"], [The system grub2-mkconfig executible name]) AC_DEFINE_UNQUOTED([GRUB2_MKCONFIG_PATH], ["$GRUB2_MKCONFIG"], [The system grub2-mkconfig executible name])
AC_ARG_WITH(static-compiler,
AS_HELP_STRING([--with-static-compiler],
[Use the given compiler to build ostree-prepare-root statically linked (default: no)]),,
[with_static_compiler=no])
AM_CONDITIONAL(BUILDOPT_USE_STATIC_COMPILER, test x$with_static_compiler != xno)
AC_SUBST(STATIC_COMPILER, $with_static_compiler)
dnl for tests dnl for tests
AS_IF([test "x$found_introspection" = xyes], [ AS_IF([test "x$found_introspection" = xyes], [
AC_PATH_PROG(GJS, [gjs]) AC_PATH_PROG(GJS, [gjs])
@ -332,7 +339,8 @@ echo "
api docs (gtk-doc): $enable_gtk_doc api docs (gtk-doc): $enable_gtk_doc
gjs-based tests: $have_gjs gjs-based tests: $have_gjs
dracut: $with_dracut dracut: $with_dracut
mkinitcpio: $with_mkinitcpio" mkinitcpio: $with_mkinitcpio
Static compiler for ostree-prepare-root: $with_static_compiler"
AS_IF([test x$with_builtin_grub2_mkconfig = xyes], [ AS_IF([test x$with_builtin_grub2_mkconfig = xyes], [
echo " builtin grub2-mkconfig (instead of system): $with_builtin_grub2_mkconfig" echo " builtin grub2-mkconfig (instead of system): $with_builtin_grub2_mkconfig"
], [ ], [