From d0d7906e72b9c5fac792c56eae89a62b349164ba Mon Sep 17 00:00:00 2001
From: Alyssa Ross <hi@alyssa.is>
Date: Thu, 25 May 2023 22:46:41 +0000
Subject: host/rootfs: switch to EROFS

Signed-off-by: Alyssa Ross <hi@alyssa.is>
---
 host/initramfs/default.nix   |  2 +-
 host/initramfs/etc/init      |  2 +-
 host/initramfs/etc/probe     |  5 ++++-
 host/rootfs/Makefile         | 19 +++++++------------
 host/rootfs/default.nix      | 21 ++++++++++++---------
 host/rootfs/etc/s6-rc/ext/up |  3 ++-
 6 files changed, 27 insertions(+), 25 deletions(-)

diff --git a/host/initramfs/default.nix b/host/initramfs/default.nix
index 899907e..fa11aef 100644
--- a/host/initramfs/default.nix
+++ b/host/initramfs/default.nix
@@ -21,7 +21,7 @@ let
   modules = makeModulesClosure {
     inherit (rootfs) firmware kernel;
     rootModules = with rootfs.nixosAllHardware.config.boot.initrd;
-      availableKernelModules ++ kernelModules ++ [ "dm-verity" "loop" ];
+      availableKernelModules ++ kernelModules ++ [ "dm-verity" "erofs" "loop" ];
   };
 
   packages = [
diff --git a/host/initramfs/etc/init b/host/initramfs/etc/init
index 5f347a5..2ec8d91 100755
--- a/host/initramfs/etc/init
+++ b/host/initramfs/etc/init
@@ -23,7 +23,7 @@ background {
 }
 importas -iu mdevd_pid !
 
-if { modprobe ext4 }
+if { modprobe erofs }
 
 # Do a blocking read on the fifo to wait for mdevd to find the
 # partition.
diff --git a/host/initramfs/etc/probe b/host/initramfs/etc/probe
index 064b792..4cbd00d 100755
--- a/host/initramfs/etc/probe
+++ b/host/initramfs/etc/probe
@@ -10,7 +10,10 @@ if -n {
     backtick -E type { lsblk -lnpo PARTTYPE $mdev }
     test $type = 56a3bbc3-aefa-43d9-a64d-7b3fd59bbc4e
   }
-  if { modprobe loop }
+  if {
+    forx -pE module { ext4 loop }
+    modprobe $module
+  }
   backtick -E uuid { lsblk -lnpo PARTUUID $mdev }
   if { mkdir -p /mnt/${uuid} }
   if { mount $mdev /mnt/${uuid} }
diff --git a/host/rootfs/Makefile b/host/rootfs/Makefile
index 73ac361..06384de 100644
--- a/host/rootfs/Makefile
+++ b/host/rootfs/Makefile
@@ -3,7 +3,7 @@
 
 include ../../lib/common.mk
 
-dest = build/rootfs.ext4
+dest = build/rootfs.erofs
 
 FILES = \
 	etc/fonts/fonts.conf \
@@ -41,21 +41,15 @@ LINKS = bin sbin
 
 BUILD_FILES = build/etc/mdev/modalias.sh build/etc/s6-rc
 
-$(dest): build/rootfs.tar
-	$(TAR2EXT4) -i build/rootfs.tar -o $@
+$(dest): ../../scripts/make-erofs.sh $(FILES) $(BUILD_FILES) build/empty
+	../../scripts/make-erofs.sh -- $@ $(PACKAGES) \
+	    $$(for file in $(FILES) $(LINKS); do printf '%s %s ' $$file $$file; done) \
+	    $$(for file in $(BUILD_FILES); do printf '%s %s ' $$file $${file#build/}; done) \
+	    $$(printf 'build/empty %s ' $(DIRS))
 
 build/empty:
 	mkdir -p $@
 
-build/rootfs.tar: build/empty $(PACKAGES_TAR) $(FILES) $(BUILD_FILES)
-	cp --no-preserve=mode -f $(PACKAGES_TAR) $@
-	tar $(TARFLAGS) --append -f $@ $(FILES) $(LINKS)
-	echo $(BUILD_FILES) | cut -d/ -f2 | \
-	    tar $(TARFLAGS) --append -f $@ -C build -T -
-	for m in $(DIRS); do \
-	    tar $(TARFLAGS) --append -hf $@ --xform="s,.*,$$m," build/empty ; \
-	done
-
 build/etc/mdev/modules.map: scripts/modprobe/gen_modules.map.awk
 	mkdir -p $$(dirname $@)
 	awk -f scripts/modprobe/gen_modules.map.awk \
@@ -112,6 +106,7 @@ build/etc/s6-rc: $(S6_RC_FILES)
 	    exit=$$?; rm -r $$dir; exit $$exit
 
 clean:
+	chmod -R +w build
 	rm -rf build
 .PHONY: clean
 
diff --git a/host/rootfs/default.nix b/host/rootfs/default.nix
index 9d1dea7..db3cd77 100644
--- a/host/rootfs/default.nix
+++ b/host/rootfs/default.nix
@@ -15,7 +15,7 @@ in
 
 pkgs.pkgsStatic.callPackage (
 
-{ lib, stdenvNoCC, nixos, runCommand, writeReferencesToFile, s6-rc, tar2ext4
+{ lib, stdenvNoCC, nixos, runCommand, writeReferencesToFile, erofs-utils, s6-rc
 , busybox, cloud-hypervisor, cryptsetup, execline, e2fsprogs, jq, kmod
 , mdevd, s6, s6-linux-init, socat, util-linuxMinimal, virtiofsd, xorg
 }:
@@ -118,12 +118,6 @@ let
     # https://lore.kernel.org/util-linux/87zgrl6ufb.fsf@alyssa.is/
     ln -s ${util-linuxMinimal}/bin/{findfs,lsblk} $out/usr/bin
   '';
-
-  packagesTar = runCommand "packages.tar" {} ''
-    cd ${packagesSysroot}
-    tar -cf $out --sort=name --mtime=@0 --verbatim-files-from \
-        -T ${writeReferencesToFile packagesSysroot} .
-  '';
 in
 
 stdenvNoCC.mkDerivation {
@@ -132,11 +126,20 @@ stdenvNoCC.mkDerivation {
   inherit src;
   sourceRoot = "source/host/rootfs";
 
-  nativeBuildInputs = [ lseek s6-rc tar2ext4 ];
+  nativeBuildInputs = [ erofs-utils lseek s6-rc ];
 
   MODULES_ALIAS = "${kernel}/lib/modules/${kernel.modDirVersion}/modules.alias";
   MODULES_ORDER = "${kernel}/lib/modules/${kernel.modDirVersion}/modules.order";
-  PACKAGES_TAR = packagesTar;
+
+  PACKAGES = [ packagesSysroot "/" ];
+
+  shellHook = ''
+    PACKAGES+=" $(sed p ${writeReferencesToFile packagesSysroot} | tr '\n' ' ')"
+  '';
+
+  preBuild = ''
+    runHook shellHook
+  '';
 
   makeFlags = [ "dest=$(out)" ];
 
diff --git a/host/rootfs/etc/s6-rc/ext/up b/host/rootfs/etc/s6-rc/ext/up
index 24a32ea..741f61f 100644
--- a/host/rootfs/etc/s6-rc/ext/up
+++ b/host/rootfs/etc/s6-rc/ext/up
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: EUPL-1.2+
-# SPDX-FileCopyrightText: 2021-2022 Alyssa Ross <hi@alyssa.is>
+# SPDX-FileCopyrightText: 2021-2023 Alyssa Ross <hi@alyssa.is>
 
+if { modprobe ext4 }
 if { /etc/mdev/wait ext }
 foreground { fsck.ext4 -fp /dev/ext }
 foreground { resize2fs /dev/ext }
-- 
cgit 1.4.1