diff --git a/example/test.sh b/example/test.sh index 6d6c439..5ddf8aa 100755 --- a/example/test.sh +++ b/example/test.sh @@ -136,6 +136,103 @@ EOF rm -rf "$work" } +test_mount() { + echo "=== Testing --mount (9p shares) ===" + + work="$(mktemp -d)" + + # --- Image 1: no WORKINGDIR, test host:guest and multi-mount --- + img="slim-test-mount" + share_dir="$work/share" + share_dir2="$work/share2" + guest_dir="/mnt/guest" + guest_dir2="/mnt/guest2" + + mkdir -p "$share_dir" "$share_dir2" + echo "hello from host" > "$share_dir/testfile.txt" + echo "second share" > "$share_dir2/testfile2.txt" + + cat > "$work/Containerfile" <<'EOF' +FROM alpine:latest +CMD ["/bin/sh", "-c", "poweroff -f"] +EOF + + echo "-- Building container image (no WORKINGDIR)..." + if ! podman build --network=none -t "$img" -f "$work/Containerfile" >/dev/null 2>&1; then + report fail "--mount (podman build failed)" + rm -rf "$work" + return + fi + + echo "-- Building slim VM..." + if ! "$SLIM_BIN" build qcow2 "$img" >/dev/null 2>&1; then + report fail "--mount (slim build failed)" + cleanup "$img" "$img" + rm -rf "$work" + return + fi + + share_canon=$(readlink -f "$share_dir") + share_canon2=$(readlink -f "$share_dir2") + + echo "-- Test 1: --mount host:guest (absolute guest path, multi-mount)..." + output=$(timeout "$TIMEOUT" "$SLIM_BIN" run "$img" \ + --mount "${share_dir}:${guest_dir}" \ + --mount "${share_dir2}:${guest_dir2}" \ + --cmd "for f in /sys/bus/virtio/drivers/9pnet_virtio/virtio*/mount_tag; do [ -f \"\$f\" ] && echo \"\$f: \$(tr -d '\\0' < \"\$f\")\"; done; mount -v; cat ${guest_dir}/testfile.txt 2>/dev/null || echo NO_FILE; cat ${guest_dir2}/testfile2.txt 2>/dev/null || echo NO_FILE2; echo MOUNT_VERIFY_DONE; poweroff -f" \ + 2>&1 || true) + + check_output "$output" "mount_tag: slim0" "--mount 9p share detected" + check_output "$output" "mount_tag: slim1" "--mount second 9p share detected" + check_output "$output" "type 9p" "--mount 9p filesystem in mount list" + check_output "$output" "hello from host" "--mount file accessible at guest path" + check_output "$output" "second share" "--mount second file accessible at guest path" + check_output "$output" "MOUNT_VERIFY_DONE" "--mount VM ran to completion" + + cleanup "$img" "$img" + + # --- Image 2: with WORKINGDIR, test relative guest path --- + img="slim-test-mount-wd" + share_dir3="$work/share3" + + mkdir -p "$share_dir3" + echo "relative share" > "$share_dir3/relfile.txt" + + cat > "$work/Containerfile.wd" <<'EOF' +FROM alpine:latest +WORKDIR /app +CMD ["/bin/sh", "-c", "poweroff -f"] +EOF + + echo "-- Building container image (WORKINGDIR /app)..." + if ! podman build --network=none -t "$img" -f "$work/Containerfile.wd" >/dev/null 2>&1; then + report fail "--mount relative (podman build failed)" + rm -rf "$work" + return + fi + + echo "-- Building slim VM..." + if ! "$SLIM_BIN" build qcow2 "$img" >/dev/null 2>&1; then + report fail "--mount relative (slim build failed)" + cleanup "$img" "$img" + rm -rf "$work" + return + fi + + echo "-- Test 2: --mount host:relative-guest (resolved against WORKINGDIR)..." + output=$(timeout "$TIMEOUT" "$SLIM_BIN" run "$img" \ + --mount "${share_dir3}:data" \ + --cmd "mount -v; cat /app/data/relfile.txt 2>/dev/null || echo NO_REL_FILE; echo REL_VERIFY_DONE; poweroff -f" \ + 2>&1 || true) + + check_output "$output" "type 9p" "--mount relative 9p filesystem in mount list" + check_output "$output" "relative share" "--mount relative file accessible at WORKINGDIR/data" + check_output "$output" "REL_VERIFY_DONE" "--mount relative VM ran to completion" + + cleanup "$img" "$img" + rm -rf "$work" +} + test_service() { echo "=== Testing nextcloud service ===" @@ -206,6 +303,8 @@ test_distro "archlinux" "archlinux:latest" "RUN pacman -Sy --noconfirm iproute2 test_user +test_mount + test_service echo "" diff --git a/src/build.rs b/src/build.rs index 32d16c9..7d24624 100644 --- a/src/build.rs +++ b/src/build.rs @@ -78,7 +78,12 @@ fn build_inner( let command = cmd.unwrap_or_else(|| inject::infer_command(&config)); let exec_script = inject::build_exec_script(&command, &config.env, config.working_dir.as_deref()); - inject::inject(mount_path, &exec_script, config.user.as_deref())?; + inject::inject( + mount_path, + &exec_script, + config.user.as_deref(), + config.working_dir.as_deref(), + )?; println!("Injected /slim/ (init + exec)"); match kind { diff --git a/src/inject.rs b/src/inject.rs index 428264d..14f06a5 100644 --- a/src/inject.rs +++ b/src/inject.rs @@ -100,9 +100,14 @@ fn install_into_rootfs(mount: &str, name: &str, mode: &str, content: &str) -> Re Ok(()) } -/// Inject /slim/init, /slim/exec, and optionally /slim/user into a mounted -/// container image rootfs. -pub fn inject(mount_path: &Path, exec_script: &str, user: Option<&str>) -> Result<()> { +/// Inject /slim/init, /slim/exec, and optionally /slim/user and /slim/workdir +/// into a mounted container image rootfs. +pub fn inject( + mount_path: &Path, + exec_script: &str, + user: Option<&str>, + working_dir: Option<&str>, +) -> Result<()> { let mount_str = mount_path.to_str().context("mount path is not UTF-8")?; install_into_rootfs(mount_str, "init", "755", SLIM_INIT)?; @@ -112,5 +117,9 @@ pub fn inject(mount_path: &Path, exec_script: &str, user: Option<&str>) -> Resul install_into_rootfs(mount_str, "user", "644", user)?; } + if let Some(dir) = working_dir.filter(|d| !d.is_empty()) { + install_into_rootfs(mount_str, "workdir", "644", dir)?; + } + Ok(()) } diff --git a/src/qemu.rs b/src/qemu.rs index b230042..e5cc29d 100644 --- a/src/qemu.rs +++ b/src/qemu.rs @@ -32,6 +32,13 @@ pub struct RunCmd { /// cmdline as slim.cmd=). Overrides the CMD inferred at build time. #[clap(long)] cmd: Option, + + /// Share a host directory into the VM via 9p. Format: + /// `` or `:`. When the guest path is + /// omitted, the host path is used. Non-absolute guest paths are + /// relative to the image's WORKINGDIR. Can be repeated. + #[clap(long)] + mount: Vec, } pub(crate) fn run( @@ -40,6 +47,7 @@ pub(crate) fn run( memory, forward, cmd, + mount, }: RunCmd, ) -> Result<()> { let reg_dir = registry_dir(&name)?; @@ -81,6 +89,35 @@ pub(crate) fn run( cmdline.push(format!("slim.cmd={encoded}")); } + // Build 9p shares for each --mount. Tags are short (slim0, slim1, …) + // because 9p mount_tag has a ~31-byte limit. The guest destination path + // is passed on the kernel cmdline as slim.mount=:. + // If no guest path is specified, the host path is used as the guest path. + let mut virtfs_args: Vec = Vec::new(); + for (i, spec) in mount.iter().enumerate() { + let (host_path, guest_path) = match spec.split_once(':') { + Some((h, g)) => (h, g), + None => (spec.as_str(), spec.as_str()), + }; + let canonical = std::path::Path::new(host_path) + .canonicalize() + .with_context(|| format!("Cannot resolve mount path '{host_path}'"))?; + let host_str = canonical + .to_str() + .context("Mount path is not valid UTF-8")?; + let tag = format!("slim{i}"); + let dest_b64 = base64::engine::general_purpose::STANDARD.encode(guest_path.as_bytes()); + + // QEMU's QemuOpts splits on commas — escape literal commas in the + // path as ",," per QEMU convention. + let host_escaped = host_str.replace(',', ",,"); + virtfs_args.push("-virtfs".into()); + virtfs_args.push(format!( + "local,path={host_escaped},mount_tag={tag},security_model=mapped-xattr" + )); + cmdline.push(format!("slim.mount={tag}:{dest_b64}")); + } + println!("Booting {name} from registry: {}", reg_dir.display()); let cmdline = cmdline.join(" "); @@ -101,6 +138,7 @@ pub(crate) fn run( .arg("-kernel") .arg(vmlinuz_path.as_os_str()) .args(&fs_args) + .args(&virtfs_args) .args(["-snapshot"]) .args(["-no-reboot"]) .args(["-append", &cmdline]) diff --git a/src/scripts/slim-init.sh b/src/scripts/slim-init.sh index b2d0ba5..7951f13 100644 --- a/src/scripts/slim-init.sh +++ b/src/scripts/slim-init.sh @@ -2,6 +2,11 @@ # slim universal init - distro-agnostic VM bootstrap. # Injected by `slim build` at /slim/init and invoked via init=/slim/init. +# === Helpers === +b64dec() { + printf '%s' "$1" | base64 -d 2>/dev/null || printf '%s' "$1" | openssl base64 -d 2>/dev/null +} + # === Devices & special filesystems === [ -c /dev/console ] || mknod -m 600 /dev/console c 5 1 mkdir -p /proc /sys /dev/pts /dev/shm @@ -34,6 +39,37 @@ ip addr add 10.0.2.15/24 dev eth0 2>/dev/null || echo "ip addr add eth0 failed" ip route add default via 10.0.2.2 2>/dev/null || echo "ip route add default failed" echo nameserver 10.0.2.3 > /etc/resolv.conf +# === 9p shares (host directories shared via --mount) === +# Each share is passed as slim.mount=: on the +# kernel cmdline. The 9p tag is short (e.g. slim0) because mount_tag +# has a ~31-byte limit; the guest path is base64-encoded. +# Non-absolute guest paths are resolved against /slim/workdir (the +# image's WORKINGDIR). +SLIM_WORKDIR="" +[ -f /slim/workdir ] && SLIM_WORKDIR=$(cat /slim/workdir 2>/dev/null) +# shellcheck disable=SC2013 # word-splitting is intentional: cmdline tokens are space-separated +for tok in $(cat /proc/cmdline 2>/dev/null); do + case "$tok" in + slim.mount=*) + v=${tok#slim.mount=} + tag=${v%%:*} + dest_b64=${v#*:} + dest=$(b64dec "$dest_b64") || echo "base64 decode failed" + if [ -n "$tag" ] && [ -n "$dest" ]; then + # Resolve relative paths against the image's WORKINGDIR + case "$dest" in + /*) ;; + *) dest="${SLIM_WORKDIR:-/}/${dest}" ;; + esac + mkdir -p "$dest" + mount -t 9p "$tag" "$dest" -o trans=virtio,version=9p2000.L 2>/dev/null \ + && echo "mounted 9p '$tag' -> '$dest'" \ + || echo "failed to mount 9p '$tag' -> '$dest'" + fi + ;; + esac +done + # === Drop privileges (respect USER directive from image config) === # /slim/user may contain a username, uid, or uid:gid (OCI image spec). # Numeric uids are resolved to a username via /etc/passwd because BusyBox @@ -75,9 +111,7 @@ for tok in $(cat /proc/cmdline 2>/dev/null); do case "$tok" in slim.cmd=*) v=${tok#slim.cmd=} - decoded=$(printf '%s' "$v" | base64 -d 2>/dev/null) \ - || decoded=$(printf '%s' "$v" | openssl base64 -d 2>/dev/null) \ - || echo "base64 decode failed" + decoded=$(b64dec "$v") || echo "base64 decode failed" if [ -n "$decoded" ]; then slim_exec "$decoded" fi