WIP: add native rust-based initramfs generator, init and qemu wrapper

.github/workflows/ci.yml

@@ -3,21 +3,38 @@ name: CI
 on:
   pull_request:
 
+# "cargo" default package results in v1.75, which doesn't support v4 lock files
+# "cargo test uses lib and bins only, as doc test breaks for some reason
+# chmod vmlinuz-`uname -r` as it's 0600 by default
+# chmod /dev/kvm to allow non-root QEMU to use it
 jobs:
   test:
     runs-on: ubuntu-latest
-    container:
-      image: registry.opensuse.org/home/mkoutny/containers/opensuse_containers_tumbleweed_containers/rapido-ci:latest
-      env:
-        KERNEL_INSTALL_MOD_PATH: /usr/
-      options:  -w /test
-      volumes:
-        - ${{ github.workspace }}:/test
-
     steps:
       - uses: actions/checkout@v4
-
-      - name: Run selftest
+      - name: install rust
         run: |
-          KERNEL_RELEASE=$(cat /usr/src/linux-obj/x86_64/default/include/config/kernel.release) /test/selftest/selftest.sh
-
+          sudo apt-get update -y
+          sudo apt-get install -y --no-install-recommends --no-install-suggests cargo-1.85 rustc qemu-system-x86
+      - name: cargo test
+        run: |
+          cargo-1.85 test --offline --lib --bins
+          pushd src/cpio
+          cargo-1.85 test --offline --lib --bins
+          popd
+          pushd src/kv-conf/
+          cargo-1.85 test --offline --lib --bins
+          popd
+      - name: build and setup rapido net
+        run: |
+          cargo-1.85 build --offline --release
+          cp -r net-conf.example/ net-conf
+          touch rapido.conf
+          sudo EDITOR=cat ./rapido setup-network -o $USER -b rapido-br -a "192.168.155.10/24"
+          sudo chmod 0644 /boot/vmlinuz-*
+          sudo chmod 0666 /dev/kvm
+      - name: boot VM test
+        run: |
+         ./rapido cut -B -x "ping -c3 192.168.155.10 && echo test passed; exit" simple-network
+         ./target/release/lscpio initrds/myinitrd
+         ./rapido boot

.gitignore

@@ -5,3 +5,4 @@ initrds/myinitrd
 *~
 *.pid
 initrds/
+target/

COPYING

@@ -1,3 +1,6 @@
+Note: Rust source code (src/, excluding src/third_party) is GPL-2.0 OR
+GPL-3.0 licensed (your choice). See per-file license headers.
+
 ----------------------------------------------------------------------
 
                   GNU LESSER GENERAL PUBLIC LICENSE

Cargo.toml

@@ -0,0 +1,22 @@
+[package]
+name = "rapido"
+description = "Quickly test Linux kernel changes"
+# The following license covers the src directory, excluding third_party.
+# SPDX-License-Identifier headers are attached to individual source files.
+license = "(GPL-2.0 OR GPL-3.0)"
+version = "0.1.0"
+edition = "2018"
+default-run = "rapido-cut"
+
+# non-lib source for binaries is carried under src/bin/
+
+[dependencies]
+# internal
+kv-conf = { path = "src/kv-conf" }
+cpio = { path = "src/cpio" }
+
+# minimal command line parameter passing
+crosvm = { path = "src/third_party/crosvm" }
+# Parse ELF to determine library dependencies. "std" provides file seek API.
+elf = { default-features = false, features = ["std"], path = "src/third_party/rust-elf" }
+# please avoid adding any more external dependencies

cut/fstests_btrfs.sh

@@ -1,42 +1,42 @@
 #!/bin/bash
 # SPDX-License-Identifier: (LGPL-2.1 OR LGPL-3.0)
-# Copyright (C) SUSE LLC 2018-2022, all rights reserved.
+# Copyright (C) SUSE S.A. 2018-2025, all rights reserved.
 
 RAPIDO_DIR="$(realpath -e ${0%/*})/.."
 . "${RAPIDO_DIR}/runtime.vars"
 
-_rt_require_dracut_args "$RAPIDO_DIR/autorun/lib/fstests.sh" \
-			"$RAPIDO_DIR/autorun/fstests_btrfs.sh" "$@"
 _rt_require_fstests
-req_inst=()
+# rapido-cut doesn't support globbing, so do it here.
+req_inst=(${FSTESTS_SRC}/ltp/* ${FSTESTS_SRC}/src/* \
+	${FSTESTS_SRC}/src/log-writes/* ${FSTESTS_SRC}/src/aio-dio-regress/*)
 _rt_require_btrfs_progs req_inst
 _rt_require_pam_mods req_inst "pam_rootok.so" "pam_limits.so"
 _rt_human_size_in_b "${FSTESTS_ZRAM_SIZE:-1G}" zram_bytes \
 	|| _fail "failed to calculate memory resources"
 # need enough memory for five zram devices
-_rt_mem_resources_set "$((3072 + (zram_bytes * 5 / 1048576)))M"
+mem_rsc="$((3072 + (zram_bytes * 5 / 1048576)))M"
 
-"$DRACUT" --install "tail blockdev ps rmdir resize dd vim grep find df sha256sum \
+PATH="target/release:${PATH}"
+rapido-cut \
+	--autorun "autorun/lib/fstests.sh autorun/fstests_btrfs.sh $*" \
+	--include "dracut.conf.d/.empty /rapido-rsc/mem/${mem_rsc}" \
+	--install "ls cat mkdir cp mv rm ln sed readlink sleep \
+		   umount findmnt dmesg uname \
+		   tail blockdev ps rmdir resize dd grep find df sha256sum \
 		   strace mkfs mkfs.ext4 e2fsck tune2fs shuf free ip su \
 		   which perl awk bc touch cut chmod true false unlink \
 		   mktemp getfattr setfattr chacl attr killall hexdump sync \
 		   id sort uniq date expr tac diff head dirname seq \
 		   basename tee egrep yes mkswap timeout realpath blkdiscard \
-		   fstrim fio logger dmsetup chattr lsattr cmp stat \
-		   dbench /usr/share/dbench/client.txt hostname getconf md5sum \
+		   fstrim logger dmsetup chattr lsattr cmp stat \
+		   hostname getconf md5sum \
 		   od wc getfacl setfacl tr xargs sysctl link truncate quota \
 		   repquota setquota quotacheck quotaon pvremove vgremove \
 		   xfs_mkfile xfs_db xfs_io wipefs filefrag losetup \
-		   chgrp du fgrep pgrep tar rev kill duperemove \
-		   fsverity keyctl openssl /etc/ssl/openssl.cnf \
-		   swapon swapoff xfs_freeze fsck ${req_inst[*]} \
-		   ${FSTESTS_SRC}/ltp/* ${FSTESTS_SRC}/src/* \
-		   ${FSTESTS_SRC}/src/log-writes/* \
-		   ${FSTESTS_SRC}/src/aio-dio-regress/*" \
-	--include "$FSTESTS_SRC" "$FSTESTS_SRC" \
-	--add-drivers "zram lzo lzo-rle dm-snapshot dm-flakey btrfs raid6_pq \
-		       loop scsi_debug dm-log-writes xxhash_generic ext4 \
-		       virtio_blk" \
-	--modules "base" \
-	"${DRACUT_RAPIDO_ARGS[@]}" \
-	"$DRACUT_OUT" || _fail "dracut failed"
+		   chgrp du fgrep pgrep tar rev kill \
+		   swapon swapoff xfs_freeze fsck ${req_inst[*]}" \
+	--try-install "resize dbench /usr/share/dbench/client.txt duperemove \
+		       fsverity keyctl openssl /etc/ssl/openssl.cnf nano fio" \
+	--include "$FSTESTS_SRC $FSTESTS_SRC" \
+	--kmods "zram lzo lzo_rle dm_snapshot dm_flakey btrfs raid6_pq \
+		 loop scsi_debug dm_log_writes xxhash_generic ext4 virtio_blk"

cut/simple_example.sh

@@ -1,40 +1,38 @@
 #!/bin/bash
 # SPDX-License-Identifier: (LGPL-2.1 OR LGPL-3.0)
-# Copyright (C) SUSE LLC 2018-2021, all rights reserved.
-
-RAPIDO_DIR="$(realpath -e ${0%/*})/.."
-. "${RAPIDO_DIR}/runtime.vars"
+# Copyright (C) SUSE S.A. 2018-2025, all rights reserved.
 
 # The job of Rapido cut scripts is to generate a VM image. This is done using
-# Dracut with a number of parameters...
-
-# Call _rt_require_dracut_args() providing script paths that will be included
-# and run on VM boot. It exports variables used in the dracut invocation below.
-_rt_require_dracut_args "$RAPIDO_DIR/autorun/simple_example.sh" "$@"
-
-# _rt_require_networking() flags that VMs using this image should have a network
-# adapter. Binaries and configuration required for networking are appended to
-# DRACUT_RAPIDO_ARGS.
-#_rt_require_networking
+# rapido-cut with a number of parameters...
 
-# VMs are booted with 2 vCPUs and 512M RAM by default. These defaults can be
-# changed, e.g. 1 vCPU + 1G RAM could be specified via:
-#_rt_cpu_resources_set 1
-#_rt_mem_resources_set 1G
+# --autorun specifies script paths that will be installed and run (in order) on
+# VM boot.
 
 # --install provides a list of binaries that should be included in the VM image.
 # Dracut will resolve shared object dependencies and add them automatically.
 
-# --include copies a specific file or directory to the given image destination.
-
-# --add-drivers provides a list of kernel modules, which will be obtained from
-# the rapido.conf KERNEL_INSTALL_MOD_PATH
-
-# --modules provides a list of *Dracut* modules. See Dracut documentation for
-# details
-"$DRACUT" \
-	--install "resize ps rmdir dd mkfs.xfs" \
-	--add-drivers "zram lzo lzo-rle" \
-	--modules "base" \
-	"${DRACUT_RAPIDO_ARGS[@]}" \
-	"$DRACUT_OUT" || _fail "dracut failed"
+# --include copies a specific file or directory-tree to the given image
+# destination. --try-install is similar but won't abort if missing.
+
+# --kmods provides a list of kernel modules, which will be obtained from
+# the rapido.conf KERNEL_INSTALL_MOD_PATH directory, or host kernel modules
+# directory if unset.
+PATH="target/release:${PATH}"
+rapido-cut \
+	--autorun "autorun/simple_example.sh $*" \
+	--install "ls cat sleep ps rmdir dd mkfs.xfs" \
+	--try-install "resize" \
+	--kmods "zram lzo lzo_rle"
+
+# rapido-cut writes the initramfs image to the rapido.conf DRACUT_OUT specified
+# path, or an explicit path provided via --output parameter.
+
+# rapido-vm boots images with 2 vCPUs and 512M RAM by default. These
+# defaults can be changed, e.g. 1 vCPU + 1G RAM could be specified via:
+#--include "dracut.conf.d/.empty /rapido-rsc/cpu/1"
+#--include "dracut.conf.d/.empty /rapido-rsc/mem/1G"
+
+# rapido VMs are not networked by default. To add networking configuration
+# (see rapido.conf NET_CONF) and systemd-network dependencies to the image,
+# a manifest/net.fest file is provided as a convenience. It can be used via:
+#--manifest net.fest

cut/simple_network.sh

@@ -1,17 +1,12 @@
 #!/bin/bash
 # SPDX-License-Identifier: (LGPL-2.1 OR LGPL-3.0)
-# Copyright (C) SUSE LLC 2022, all rights reserved.
+# Copyright (C) SUSE S.A. 2022-2025, all rights reserved.
 
-RAPIDO_DIR="$(realpath -e ${0%/*})/.."
-. "${RAPIDO_DIR}/runtime.vars"
-
-_rt_require_dracut_args "$RAPIDO_DIR/autorun/simple_network.sh" "$@"
-_rt_require_networking
-_rt_cpu_resources_set "1"
-_rt_mem_resources_set "512M"
-
-"$DRACUT" \
-	--install "resize ps nc hostname" \
-	--modules "base" \
-	"${DRACUT_RAPIDO_ARGS[@]}" \
-	"$DRACUT_OUT" || _fail "dracut failed"
+PATH="target/release:${PATH}"
+rapido-cut \
+	--autorun "autorun/simple_network.sh $*" \
+	--install "ps nc hostname cat ls" \
+	--try-install "resize" \
+	--manifest net.fest \
+	--include "dracut.conf.d/.empty /rapido-rsc/cpu/1" \
+	--include "dracut.conf.d/.empty /rapido-rsc/mem/512M"

manifest/net.fest

@@ -0,0 +1,12 @@
+install="udevadm systemd-udevd systemd-networkd systemd-networkd-wait-online ip
+	ping"
+
+# the /rapido-rsc/net destination path is special in that it tells
+# rapido-vm to also assign tap devices to the VM
+include="${VM_NET_CONF} /rapido-rsc/net"
+
+# rapido-init includes logic to bring up network.
+# we could split it out and do something like:
+#autorun="rapido-init-network"
+
+kmods="virtio_net af_packet"

rapido

@@ -21,13 +21,14 @@ rapido_setup_network()
 # vm is an alias for boot
 rapido_vm()
 {
-	${RAPIDO_DIR}/vm.sh
+	rapido_boot
 }
 
 short_help["boot"]="Boot previously prepared test"
 rapido_boot()
 {
-	${RAPIDO_DIR}/vm.sh
+	PATH="target/release:${PATH}"
+	rapido-vm
 }
 
 cut_usage()
@@ -98,7 +99,7 @@ rapido_cut()
 	local cut_status=$?
 	[ $cut_status -ne 0 ] && exit $cut_status
 	[ -n "$boot_img" ] || exit 0
-	"${RAPIDO_DIR}/vm.sh"
+	rapido_boot
 }
 
 short_help["list"]="List testcases"

runtime.vars

@@ -280,11 +280,12 @@ _rt_require_dracut_args() {
 	# destination filename.
 	local init_src=$1 init_dst kver kmods=()
 
-	# Specify core init scripts responsible for starting autorun.
-	# The Dracut "cmdline" hook is executed prior to root parameter parsing.
+	# Specify core init responsible for starting autorun.
 	local env_src="$RAPIDO_DIR/vm_autorun.env"
-	local rinit_src="$RAPIDO_DIR/autorun/00-rapido-init.sh"
-	local rinit_dst="/lib/dracut/hooks/cmdline/00-rapido-init.sh"
+	local rinit_src="$RAPIDO_DIR/target/release/rapido-init"
+	[[ -f $rinit_src ]] \
+		|| _fail "$rinit_src missing. Build via: cargo build --release"
+	local rinit_dst="/rdinit"
 	local conf_src="$RAPIDO_CONF"
 	[[ -f $RAPIDO_CONF ]] || conf_src="${RAPIDO_DIR}/dracut.conf.d/.empty"
 	DRACUT_RAPIDO_ARGS+=(--include "$conf_src" /rapido.conf \

selftest/test/002

@@ -8,17 +8,7 @@ set timeout 60
 spawn ./rapido cut -B simple-example
 expect {
 	timeout {exit 1}
-	"*** Creating initramfs image file"
-}
-expect {
-	timeout {exit 1}
-	eof
-}
-# confirm that image was written at DRACUT_OUT path
-spawn lsinitrd $::env(RAPIDO_SELFTEST_TMPDIR)/myinitrd
-expect {
-	timeout {exit 1}
-	"Version: dracut"
+	"myinitrd written"
 }
 expect {
 	timeout {exit 1}