[Dev] [PATCH] make librechroot target arch agnostic

[Andreas Grapentin]

Hi,

in the light of my attempts to create a riscv64 parabola port, I would
like to see the following changes made to librechroot.

The patch removes the hard-coded arm cross arch checks in favour of a
more general approach, that works for more architectures. As a side
effect, this now also would behave correctly when creating x86 chroots
on arm, although why anyone would choose to do this is beyond me.

Looks OK?

Cheers,
Andreas

---
 src/chroot-tools/librechroot | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/src/chroot-tools/librechroot b/src/chroot-tools/librechroot
index 27e17bd..750f34c 100755
--- a/src/chroot-tools/librechroot
+++ b/src/chroot-tools/librechroot
@@ -69,17 +69,21 @@ hack_arch_nspawn_flags() {
 		CARCH="$(uname -m)"
 	fi
 
-	if [[ "$CARCH" == armv7h ]] && ! setarch armv7l /bin/true 2>/dev/null; then
-		# We're running an ARM chroot on a non-ARM processor
+	case $CARCH in
+		armv7h) _setarch=armv7l ; _qemuarch=arm    ;;
+		*)      _setarch=$CARCH ; _qemuarch=$CARCH ;;
+	esac
+	if ! setarch $_setarch /bin/true 2>/dev/null; then
+		# We're running a cross-arch chroot
 
 		# Make sure that qemu-static is set up with binfmt_misc
 		if [[ -z $(grep -l -xF \
-			     -e 'interpreter /usr/bin/qemu-arm-static' \
+			     -e "interpreter /usr/bin/qemu-$_qemuarch-static" \
 			     -r -- /proc/sys/fs/binfmt_misc 2>/dev/null \
 			   | xargs -r grep -xF 'enabled') ]]
 		then
-			error 'Cannot cross-compile for ARM on x86'
-			plain 'This requires a binfmt_misc entry for qemu-arm-static.'
+			error 'Cannot cross-compile for %s on %s' $CARCH $(uname -m)
+			plain 'This requires a binfmt_misc entry for qemu-%s-static.' $_qemuarch
 			prose 'Such a binfmt_misc entry is provided by the %s
 			       package.  If you have it installed, but still see
 			       this message, you may need to restart %s.' \
@@ -88,13 +92,13 @@ hack_arch_nspawn_flags() {
 		fi
 
 		# Let qemu/binfmt_misc do its thing
-		arch_nspawn_flags+=(-f /usr/bin/qemu-arm-static -s)
+		arch_nspawn_flags+=(-f /usr/bin/qemu-$_qemuarch-static -s)
 
 		# The -any packages are built separately for ARM from
 		# x86, so if we use the same CacheDir as the x86 host,
 		# then there will be PGP errors.
-		mkdir -p /var/cache/pacman/pkg-arm
-		arch_nspawn_flags+=(-c /var/cache/pacman/pkg-arm)
+		mkdir -p /var/cache/pacman/pkg-$CARCH
+		arch_nspawn_flags+=(-c /var/cache/pacman/pkg-$CARCH)
 	fi
 }
 
-- 
2.16.2


-- 

------------------------------------------------------------------------------
Andreas Grapentin, M.Sc.          Research Assistant @ Hasso-Plattner-Institut
Operating Systems and Middleware Group              www.dcl.hpi.uni-potsdam.de
Phone: +49 (0) 331 55 09-238                        Fax: +49 (0) 331 55 09-229
my GPG Public Key:                 https://files.grapentin.org/.gpg/public.key
------------------------------------------------------------------------------
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 488 bytes
Desc: not available
URL: <https://lists.parabola.nu/pipermail/dev/attachments/20180227/67932b48/attachment.sig>