Replace mkinitrd(1) with tar(1).

The custom initrd format was originally useful when it was mounted,
however it has been extracted into the ramfs for a very long time and
has no advantages over the standard tar format which can be readily
created and modified using standard tools. The kernel initrd(7) support
already supports tar, so this change simply switches the format.

Makefile

@@ -73,10 +73,10 @@ include build-aux/dirs.mak
 
 BUILD_NAME:=sortix-$(RELEASE)-$(MACHINE)
 
-LIVE_INITRD:=$(SORTIX_BUILDS_DIR)/$(BUILD_NAME).live.initrd
+LIVE_INITRD:=$(SORTIX_BUILDS_DIR)/$(BUILD_NAME).live.tar
-OVERLAY_INITRD:=$(SORTIX_BUILDS_DIR)/$(BUILD_NAME).overlay.initrd
+OVERLAY_INITRD:=$(SORTIX_BUILDS_DIR)/$(BUILD_NAME).overlay.tar
-SRC_INITRD:=$(SORTIX_BUILDS_DIR)/$(BUILD_NAME).src.initrd
+SRC_INITRD:=$(SORTIX_BUILDS_DIR)/$(BUILD_NAME).src.tar
-SYSTEM_INITRD:=$(SORTIX_BUILDS_DIR)/$(BUILD_NAME).system.initrd
+SYSTEM_INITRD:=$(SORTIX_BUILDS_DIR)/$(BUILD_NAME).system.tar
 
 .PHONY: all
 all: sysroot
@@ -455,7 +455,6 @@ $(LIVE_INITRD): sysroot
 	echo "include /etc/default/passwd.d/*" >> $(LIVE_INITRD).d/etc/passwd
 	echo "root::0:root" > $(LIVE_INITRD).d/etc/group
 	echo "include /etc/default/group.d/*" >> $(LIVE_INITRD).d/etc/group
-	mkdir -p $(LIVE_INITRD).d/home
 	mkdir -p $(LIVE_INITRD).d/root -m 700
 	cp -RT "$(SYSROOT)/etc/skel" $(LIVE_INITRD).d/root
 	(echo "You can view the documentation for new users by typing:" && \
@@ -466,19 +465,23 @@ $(LIVE_INITRD): sysroot
 	 echo && \
 	 echo "  man installation") > $(LIVE_INITRD).d/root/welcome
 	tix-collection $(LIVE_INITRD).d create --platform=$(HOST) --prefix= --generation=2
-	mkinitrd --format=sortix-initrd-2 $(LIVE_INITRD).d -o $(LIVE_INITRD)
+	LC_ALL=C ls -A $(LIVE_INITRD).d | \
+	tar -cf $(LIVE_INITRD) -C $(LIVE_INITRD).d --numeric-owner --owner=0 --group=0 -T -
 	rm -rf $(LIVE_INITRD).d
 
 .PHONY: $(OVERLAY_INITRD)
 $(OVERLAY_INITRD): sysroot
 	test ! -d "$(SYSROOT_OVERLAY)" || \
-	mkinitrd --format=sortix-initrd-2 "$(SYSROOT_OVERLAY)" -o $(OVERLAY_INITRD)
+	LC_ALL=C ls -A "$(SYSROOT_OVERLAY)" | \
+	tar -cf $(OVERLAY_INITRD) -C "$(SYSROOT_OVERLAY)" --numeric-owner --owner=0 --group=0 -T -
 
 $(SRC_INITRD): sysroot
-	mkinitrd --format=sortix-initrd-2 --manifest="$(SYSROOT)/tix/manifest/src" "$(SYSROOT)" -o $(SRC_INITRD)
+	sed -E 's,^/,,' "$(SYSROOT)/tix/manifest/src" | \
+	tar -cf $(SRC_INITRD) -C "$(SYSROOT)" --numeric-owner --owner=0 --group=0 --no-recursion -T - tix/manifest/src
 
 $(SYSTEM_INITRD): sysroot
-	mkinitrd --format=sortix-initrd-2 --manifest="$(SYSROOT)/tix/manifest/system" "$(SYSROOT)" -o $(SYSTEM_INITRD)
+	sed -E 's,^/,,' "$(SYSROOT)/tix/manifest/system" | \
+	tar -cf $(SYSTEM_INITRD) -C "$(SYSROOT)" --numeric-owner --owner=0 --group=0 --no-recursion -T - tix/manifest/system
 
 # Packaging
 
@@ -499,29 +502,29 @@ $(SORTIX_BUILDS_DIR)/$(BUILD_NAME).iso: sysroot $(LIVE_INITRD) $(OVERLAY_INITRD)
 	build-aux/iso-repository.sh $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso/repository
 ifeq ($(SORTIX_ISO_COMPRESSION),xz)
 	xz -c "$(SYSROOT)/boot/sortix.bin" > $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso/boot/sortix.bin.xz
-	xz -c $(LIVE_INITRD) > $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso/boot/live.initrd.xz
+	xz -c $(LIVE_INITRD) > $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso/boot/live.tar.xz
 	test ! -e "$(OVERLAY_INITRD)" || \
-	xz -c $(OVERLAY_INITRD) > $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso/boot/overlay.initrd.xz
+	xz -c $(OVERLAY_INITRD) > $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso/boot/overlay.tar.xz
-	xz -c $(SRC_INITRD) > $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso/boot/src.initrd.xz
+	xz -c $(SRC_INITRD) > $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso/boot/src.tar.xz
-	xz -c $(SYSTEM_INITRD) > $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso/boot/system.initrd.xz
+	xz -c $(SYSTEM_INITRD) > $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso/boot/system.tar.xz
 	build-aux/iso-grub-cfg.sh --platform $(HOST) --version $(VERSION) $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso
 	grub-mkrescue --compress=xz -o $(SORTIX_BUILDS_DIR)/$(BUILD_NAME).iso $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso
 else ifeq ($(SORTIX_ISO_COMPRESSION),gzip)
 	gzip -c "$(SYSROOT)/boot/sortix.bin" > $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso/boot/sortix.bin.gz
-	gzip -c $(LIVE_INITRD) > $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso/boot/live.initrd.gz
+	gzip -c $(LIVE_INITRD) > $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso/boot/live.tar.gz
 	test ! -e "$(OVERLAY_INITRD)" || \
-	gzip -c $(OVERLAY_INITRD) > $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso/boot/overlay.initrd.gz
+	gzip -c $(OVERLAY_INITRD) > $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso/boot/overlay.tar.gz
-	gzip -c $(SRC_INITRD) > $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso/boot/src.initrd.gz
+	gzip -c $(SRC_INITRD) > $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso/boot/src.tar.gz
-	gzip -c $(SYSTEM_INITRD) > $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso/boot/system.initrd.gz
+	gzip -c $(SYSTEM_INITRD) > $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso/boot/system.tar.gz
 	build-aux/iso-grub-cfg.sh --platform $(HOST) --version $(VERSION) $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso
 	grub-mkrescue --compress=gz -o $(SORTIX_BUILDS_DIR)/$(BUILD_NAME).iso $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso
 else # none
 	cp "$(SYSROOT)/boot/sortix.bin" $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso/boot/sortix.bin
-	cp $(LIVE_INITRD) $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso/boot/live.initrd
+	cp $(LIVE_INITRD) $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso/boot/live.tar
 	test ! -e "$(OVERLAY_INITRD)" || \
-	cp $(OVERLAY_INITRD) $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso/boot/overlay.initrd
+	cp $(OVERLAY_INITRD) $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso/boot/overlay.tar
-	cp $(SRC_INITRD) $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso/boot/src.initrd
+	cp $(SRC_INITRD) $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso/boot/src.tar
-	cp $(SYSTEM_INITRD) $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso/boot/system.initrd
+	cp $(SYSTEM_INITRD) $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso/boot/system.tar
 	build-aux/iso-grub-cfg.sh --platform $(HOST) --version $(VERSION) $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso
 	grub-mkrescue -o $(SORTIX_BUILDS_DIR)/$(BUILD_NAME).iso $(SORTIX_BUILDS_DIR)/$(BUILD_NAME)-iso
 endif
@@ -555,25 +558,25 @@ $(SORTIX_RELEASE_DIR)/$(RELEASE)/$(MACHINE)/boot: $(SORTIX_RELEASE_DIR)/$(RELEAS
 $(SORTIX_RELEASE_DIR)/$(RELEASE)/$(MACHINE)/boot/sortix.bin.xz: sysroot $(SORTIX_RELEASE_DIR)/$(RELEASE)/$(MACHINE)/boot
 	xz -c "$(SYSROOT)/boot/sortix.bin" > $@
 
-$(SORTIX_RELEASE_DIR)/$(RELEASE)/$(MACHINE)/boot/live.initrd.xz: $(LIVE_INITRD) $(SORTIX_RELEASE_DIR)/$(RELEASE)/$(MACHINE)/boot
+$(SORTIX_RELEASE_DIR)/$(RELEASE)/$(MACHINE)/boot/live.tar.xz: $(LIVE_INITRD) $(SORTIX_RELEASE_DIR)/$(RELEASE)/$(MACHINE)/boot
 	xz -c $< > $@
 
-$(SORTIX_RELEASE_DIR)/$(RELEASE)/$(MACHINE)/boot/overlay.initrd.xz: $(OVERLAY_INITRD) $(SORTIX_RELEASE_DIR)/$(RELEASE)/$(MACHINE)/boot
+$(SORTIX_RELEASE_DIR)/$(RELEASE)/$(MACHINE)/boot/overlay.tar.xz: $(OVERLAY_INITRD) $(SORTIX_RELEASE_DIR)/$(RELEASE)/$(MACHINE)/boot
 	test ! -e $< || xz -c $< > $@
 
-$(SORTIX_RELEASE_DIR)/$(RELEASE)/$(MACHINE)/boot/src.initrd.xz: $(SRC_INITRD) $(SORTIX_RELEASE_DIR)/$(RELEASE)/$(MACHINE)/boot
+$(SORTIX_RELEASE_DIR)/$(RELEASE)/$(MACHINE)/boot/src.tar.xz: $(SRC_INITRD) $(SORTIX_RELEASE_DIR)/$(RELEASE)/$(MACHINE)/boot
 	xz -c $< > $@
 
-$(SORTIX_RELEASE_DIR)/$(RELEASE)/$(MACHINE)/boot/system.initrd.xz: $(SYSTEM_INITRD) $(SORTIX_RELEASE_DIR)/$(RELEASE)/$(MACHINE)/boot
+$(SORTIX_RELEASE_DIR)/$(RELEASE)/$(MACHINE)/boot/system.tar.xz: $(SYSTEM_INITRD) $(SORTIX_RELEASE_DIR)/$(RELEASE)/$(MACHINE)/boot
 	xz -c $< > $@
 
 .PHONY: release-boot
 release-boot: \
   $(SORTIX_RELEASE_DIR)/$(RELEASE)/$(MACHINE)/boot/sortix.bin.xz \
-  $(SORTIX_RELEASE_DIR)/$(RELEASE)/$(MACHINE)/boot/live.initrd.xz \
+  $(SORTIX_RELEASE_DIR)/$(RELEASE)/$(MACHINE)/boot/live.tar.xz \
-  $(SORTIX_RELEASE_DIR)/$(RELEASE)/$(MACHINE)/boot/overlay.initrd.xz \
+  $(SORTIX_RELEASE_DIR)/$(RELEASE)/$(MACHINE)/boot/overlay.tar.xz \
-  $(SORTIX_RELEASE_DIR)/$(RELEASE)/$(MACHINE)/boot/src.initrd.xz \
+  $(SORTIX_RELEASE_DIR)/$(RELEASE)/$(MACHINE)/boot/src.tar.xz \
-  $(SORTIX_RELEASE_DIR)/$(RELEASE)/$(MACHINE)/boot/system.initrd.xz \
+  $(SORTIX_RELEASE_DIR)/$(RELEASE)/$(MACHINE)/boot/system.tar.xz \
 
 .PHONY: release-iso
 release-iso: $(SORTIX_RELEASE_DIR)/$(RELEASE)/builds/$(BUILD_NAME).iso

build-aux/iso-grub-cfg.sh

@@ -1,5 +1,5 @@
 #!/bin/sh
-# Copyright (c) 2018, 2022 Jonas 'Sortie' Termansen.
+# Copyright (c) 2018, 2022, 2023 Jonas 'Sortie' Termansen.
 #
 # Permission to use, copy, modify, and distribute this software for any
 # purpose with or without fee is hereby granted, provided that the above
@@ -111,10 +111,10 @@ isinset() {
 cd "$directory"
 
 kernel=$(maybe_compressed boot/sortix.bin)
-live_initrd=$(maybe_compressed boot/live.initrd)
+live_initrd=$(maybe_compressed boot/live.tar)
-overlay_initrd=$(maybe_compressed boot/overlay.initrd)
+overlay_initrd=$(maybe_compressed boot/overlay.tar)
-src_initrd=$(maybe_compressed boot/src.initrd)
+src_initrd=$(maybe_compressed boot/src.tar)
-system_initrd=$(maybe_compressed boot/system.initrd)
+system_initrd=$(maybe_compressed boot/system.tar)
 ports=$(ls repository |
        grep -E '\.tix\.tar\.xz$' |
        sed -E 's/\.tix\.tar\.xz$//')

kernel/.gitignore

@@ -4,7 +4,6 @@
 *.iso
 *.so
 *.a
-*.initrd
 *.out
 kb/default-kblayout
 kb/default-kblayout.h

share/man/man7/initrd.7

@@ -8,7 +8,9 @@
 .Pa /boot/sortix.initrd
 .Sh DESCRIPTION
 .Pa /boot/sortix.initrd
-is an archive of a minimal userland loaded by the bootloader and passed to the
+is a
+.Xr tar 1
+archive of a minimal userland loaded by the bootloader and passed to the
 .Xr kernel 7
 that extracts it into the initial kernel memory root filesystem.
 The kernel invokes the
@@ -16,20 +18,13 @@ The kernel invokes the
 extracted from the initrd as
 .Pa /sbin/init .
 .Pp
-The initrd is in the custom format made by
-.Xr mkinitrd 8
-and can be viewed with
-.Xr initrdfs 8 .
-.Pp
 The
 .Xr update-initrd 8
 program creates a minimal initrd that locates the root filesystem and chain
 boots it as described in
 .Xr init 8 .
 .Sh SEE ALSO
-.Xr initrd 7 ,
+.Xr tar 1 ,
 .Xr kernel 7 ,
 .Xr init 8 ,
-.Xr initrdfs 8 ,
-.Xr mkinitrd 8 ,
 .Xr update-initrd 8

share/man/man7/release-iso-bootconfig.7

@@ -384,13 +384,13 @@ as a multiboot module with the
 command line.
 .Pp
 Load
-.Pa /boot/system.initrd.xz ,
+.Pa /boot/system.tar.xz ,
-.Pa /boot/src.initrd.xz
+.Pa /boot/src.tar.xz
 (if
 .Sy $enable_src ) ,
-.Pa /boot/live.initrd.xz ,
+.Pa /boot/live.tar.xz ,
 and
-.Pa /boot/overlay.initrd.xz
+.Pa /boot/overlay.tar.xz
 (only if a
 .Pa sysroot-overlay
 directory existed when making the release .iso)

update-initrd/update-initrd

@@ -1,5 +1,5 @@
 #!/bin/sh
-# Copyright (c) 2015, 2016, 2017 Jonas 'Sortie' Termansen.
+# Copyright (c) 2015, 2016, 2017, 2023 Jonas 'Sortie' Termansen.
 #
 # Permission to use, copy, modify, and distribute this software for any
 # purpose with or without fee is hereby granted, provided that the above
@@ -14,7 +14,7 @@
 # OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #
 # update-initrd
-# Generate a mkinitrd that locates and chain boots the real root filesystem.
+# Generate an initrd(7) that locates and chain boots the real root filesystem.
 
 set -e
 
@@ -86,4 +86,6 @@ require chain exit-code
 EOF
 fi
 mkdir -p "$sysroot/boot"
-mkinitrd --format=sortix-initrd-2 "$tmp" -o "$sysroot/boot/sortix.initrd" > /dev/null
+LC_AL=C ls -A "$tmp" |
+tar -C "$tmp" -cf "$sysroot/boot/sortix.initrd" \
+    --numeric-owner --owner=0 --group=0 -T -

update-initrd/update-initrd.8

@@ -63,12 +63,11 @@ directory instead and store the result as
 .Nm
 will exit 0 on success and non-zero otherwise.
 .Sh SEE ALSO
+.Xr tar 1 ,
 .Xr fstab 5 ,
 .Xr initrd 7 ,
 .Xr disked 8 ,
 .Xr extfs 8 ,
 .Xr init 8 ,
-.Xr initrdfs 8 ,
-.Xr mkinitrd 8 ,
 .Xr sysmerge 8 ,
 .Xr update-grub 8