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Author SHA1 Message Date
hulthe 8fdac31160 Inject universal /slim/init instead of requiring container-specific setup
CI / build (pull_request) Successful in 13s
slim now works with any Containerfile by injecting distro-agnostic scripts
at build time:

- /slim/init: mounts special filesystems, configures networking (static
  QEMU slirp), sets up cgroup2, timezone, and rootless container prereqs.
  Parses slim.cmd=<base64> from the kernel cmdline for runtime overrides,
  otherwise execs /slim/exec.

- /slim/exec: generated from the image's CMD/ENTRYPOINT (via podman image
  inspect), overridable via --cmd at build and run time.

Changes:
- New src/inject.rs: inspect image config, infer command, generate
  /slim/exec script, inject /slim/ into mounted rootfs
- New src/scripts/slim-init.sh: the universal init script (include_str!)
- build.rs: rename --init to --cmd, inject scripts before packing,
  drop Meta::save, restructure to ensure unmount always runs
- qemu.rs: hardcode init=/slim/init, add --cmd (base64 on cmdline),
  drop Meta::load, add -no-reboot
- Remove src/meta.rs and meta.toml (no longer needed)
- Cargo.toml: add serde_json + base64, remove unused walkdir + cpio + toml
- Example Containerfiles simplified to plain FROM + CMD
- New example/test.sh for manual verification
- README updated for new workflow
2026-09-08 09:16:30 +02:00
15 changed files with 247 additions and 5073 deletions
-4
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@@ -1,4 +0,0 @@
[submodule "linux"]
path = kernel/linux
url = https://github.com/torvalds/linux.git
shallow = true
Generated
+24 -57
View File
@@ -66,37 +66,15 @@ checksum = "330a5ed07fa54e4702c9d6c4174f74427fc0ef6e214bbd677ae50a5099946470"
[[package]]
name = "base64"
version = "0.23.1"
version = "0.22.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "ac07cdecf99051d9a5238b80f35af32cdeba5b336e55d957b318b50137e18da5"
checksum = "72b3254f16251a8381aa12e40e3c4d2f0199f8c6508fbecb9d91f575e0fbb8c6"
[[package]]
name = "bitflags"
version = "2.13.2"
version = "2.13.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "3ded4057c258ba199e2d26386d3af3780957ecaee6c4ef4041c6b4b8b97c0b06"
[[package]]
name = "boco"
version = "0.1.0"
dependencies = [
"anyhow",
"base64",
"clap",
"flate2",
"serde",
"serde_json",
"tempfile",
"xdg",
]
[[package]]
name = "boco-init"
version = "0.1.0"
dependencies = [
"base64",
"nix",
]
checksum = "b588b76d00fde79687d7646a9b5bdf3cc0f655e0bbd080335a95d7e96f3587da"
[[package]]
name = "cfg-if"
@@ -104,12 +82,6 @@ version = "1.0.4"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "9330f8b2ff13f34540b44e946ef35111825727b38d33286ef986142615121801"
[[package]]
name = "cfg_aliases"
version = "0.2.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "f079e83a288787bcd14a6aea84cee5c87a67c5a3e660c30f557a3d24761b3527"
[[package]]
name = "clap"
version = "4.6.6"
@@ -183,13 +155,12 @@ checksum = "da7c62ceae207dd37ea5b845da6a0696c799f85e97da1ab5b7910be3c1c80223"
[[package]]
name = "flate2"
version = "1.1.10"
version = "1.1.9"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "6e634e2e0ebac1ee034020da1ca582e17ffe4e0f5e985823721e168928136dcb"
checksum = "843fba2746e448b37e26a819579957415c8cef339bf08564fe8b7ddbd959573c"
dependencies = [
"crc32fast",
"miniz_oxide",
"zlib-rs",
]
[[package]]
@@ -241,26 +212,14 @@ checksum = "cf8baf1c55e62ffcace7a9f06f4bd9cd3f0c4beb022d3b367256b91b87513d98"
[[package]]
name = "miniz_oxide"
version = "0.9.1"
version = "0.8.9"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "b63fbc4a50860e98e7b2aa7804ded1db5cbc3aff9193adaff57a6931bf7c4b4c"
checksum = "1fa76a2c86f704bdb222d66965fb3d63269ce38518b83cb0575fca855ebb6316"
dependencies = [
"adler2",
"simd-adler32",
]
[[package]]
name = "nix"
version = "0.31.3"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "cf20d2fde8ff38632c426f1165ed7436270b44f199fc55284c38276f9db47c3d"
dependencies = [
"bitflags",
"cfg-if",
"cfg_aliases",
"libc",
]
[[package]]
name = "once_cell"
version = "1.21.4"
@@ -359,6 +318,20 @@ version = "0.3.10"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "3a219298ac11a56ea9a6d2120044824d6f01aeb034955e7af7bc16858527deea"
[[package]]
name = "slim"
version = "0.1.0"
dependencies = [
"anyhow",
"base64",
"clap",
"flate2",
"serde",
"serde_json",
"tempfile",
"xdg",
]
[[package]]
name = "strsim"
version = "0.11.1"
@@ -367,9 +340,9 @@ checksum = "7da8b5736845d9f2fcb837ea5d9e2628564b3b043a70948a3f0b778838c5fb4f"
[[package]]
name = "syn"
version = "3.0.5"
version = "3.0.4"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "12df2e0110f65b775f769bb17ef989067a1d931b2eb822bd4346631eeada89f9"
checksum = "e6275cddf4610d1775e6d1fe9469b2e77d0f39fd98fb7450901b821e0c53649f"
dependencies = [
"proc-macro2",
"quote",
@@ -422,12 +395,6 @@ version = "3.0.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "2fb433233f2df9344722454bc7e96465c9d03bff9d77c248f9e7523fe79585b5"
[[package]]
name = "zlib-rs"
version = "0.6.7"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "34b31d188d9d685a4f9c7b46d6e36631b07058d2cfe190267adce54dc230bf12"
[[package]]
name = "zmij"
version = "1.0.23"
+2 -10
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@@ -1,19 +1,11 @@
[workspace]
members = [".", "init"]
[profile.release]
opt-level = "z"
lto = true
strip = true
[package]
name = "boco"
name = "slim"
version = "0.1.0"
edition = "2024"
[dependencies]
anyhow = "1.0.104"
base64 = "0.23"
base64 = "0.22"
clap = { version = "4.6.6", features = ["derive"] }
flate2 = "1.1.9"
serde = { version = "1.0.229", features = ["derive"] }
+17 -26
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@@ -1,41 +1,32 @@
# boco
# slim
Turn container images into bootable VMs
Turning containers into bootable VMs
## Example
```Dockerfile
# ./example/alpine/Containerfile
FROM alpine:latest
CMD ["/bin/sh"]
```
```sh
# Build the container
podman build ./example/alpine -t boco-alpine
podman build ./example/alpine -t slim-alpine
# Make the container bootable. boco injects a custom init program,
# Make the container bootable. slim injects /slim/init and /slim/exec,
# then packs the rootfs as a qcow2 disk.
boco build qcow2 boco-alpine
slim build qcow2 slim-alpine
# Boot the image using QEMU, and drop into /bin/sh.
boco boot boco-alpine
# Boot the image using QEMU. The container's CMD runs automatically.
slim run slim-alpine
# Override the command at runtime (base64-encoded on the kernel cmdline):
slim run slim-alpine --cmd '/bin/sh'
# Override the command at build time (baked into /slim/exec):
slim build qcow2 slim-alpine --cmd '/bin/sh'
# Cleanup
boco image rm boco-alpine
podman image rm boco-alpine
```
Can also be used to boot a more traditional systemd-based VM:
```Dockerfile
FROM archlinux:latest
# This works! Although you should probably add a user or some services.
CMD ["/sbin/init"]
slim image rm slim-alpine
podman image rm slim-alpine
```
## Kernel
boco boots VMs using a shared kernel at `$XDG_DATA_HOME/boco/registry/vmlinuz`.
Place a suitable x86 bzImage there before running `boco boot`.
slim boots VMs using a shared kernel at `$XDG_DATA_HOME/slim-rs/vmlinuz`.
Place a suitable x86 bzImage there before running `slim run`.
+24 -280
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@@ -1,12 +1,11 @@
#!/bin/bash
# Test script for boco - boots containers and verifies CMD inference/override.
# Requires: podman, qemu-system-x86_64, KVM, curl, and a kernel at
# $XDG_DATA_HOME/boco/registry/vmlinuz.
# Test script for slim - boots containers and verifies CMD inference/override.
# Requires: podman, qemu-system-x86_64, KVM, and a kernel at
# $XDG_DATA_HOME/slim-rs/vmlinuz.
set -u
SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
TARGET_DIR="${CARGO_TARGET_DIR:-$SCRIPT_DIR/../target}"
BOCO_BIN="$TARGET_DIR/debug/boco"
SLIM_BIN="$SCRIPT_DIR/../target/debug/slim"
TIMEOUT=120
pass=0
@@ -34,7 +33,7 @@ check_output() {
}
cleanup() {
"$BOCO_BIN" image rm "$1" >/dev/null 2>&1 || true
"$SLIM_BIN" image rm "$1" >/dev/null 2>&1 || true
podman image rm "$2" >/dev/null 2>&1 || true
}
@@ -52,48 +51,48 @@ test_distro() {
cat > "$work/Containerfile.infer" <<EOF
FROM $from
$extra_setup
CMD ["/bin/sh", "-c", "echo CMD_INFERRED_OK; wget -q -O /dev/null http://1.1.1.1 2>/dev/null && echo CONN_OK; wget -q -O /dev/null http://example.org 2>/dev/null && echo DNS_OK; poweroff -f"]
CMD ["/bin/sh", "-c", "echo CMD_INFERRED_OK; ping -c1 1.1.1.1 >/dev/null 2>&1 && echo PING_OK; ping -c1 example.org >/dev/null 2>&1 && echo DNS_OK; poweroff -f"]
EOF
img="boco-test-$distro-infer"
img="slim-test-$distro-infer"
if podman build -t "$img" -f "$work/Containerfile.infer" >/dev/null 2>&1; then
"$BOCO_BIN" build qcow2 "$img" >/dev/null 2>&1
output=$(timeout "$TIMEOUT" "$BOCO_BIN" boot "$img" 2>&1 || true)
"$SLIM_BIN" build qcow2 "$img" >/dev/null 2>&1
output=$(timeout "$TIMEOUT" "$SLIM_BIN" run "$img" 2>&1 || true)
check_output "$output" "CMD_INFERRED_OK" "$distro CMD-inferred"
check_output "$output" "CONN_OK" "$distro connect to 1.1.1.1"
check_output "$output" "PING_OK" "$distro ping 1.1.1.1"
check_output "$output" "DNS_OK" "$distro DNS lookup"
else
report fail "$distro CMD-inferred (podman build failed)"
fi
cleanup "$img" "$img"
# === Test 2: boco boot --cmd override ===
echo "-- Test 2: boco boot --cmd override"
# === Test 2: slim run --cmd override ===
echo "-- Test 2: slim run --cmd override"
cat > "$work/Containerfile.run" <<EOF
FROM $from
$extra_setup
CMD ["/bin/sh", "-c", "echo SHOULD_NOT_APPEAR; poweroff -f"]
EOF
img="boco-test-$distro-run"
img="slim-test-$distro-run"
if podman build -t "$img" -f "$work/Containerfile.run" >/dev/null 2>&1; then
"$BOCO_BIN" build qcow2 "$img" >/dev/null 2>&1
output=$(timeout "$TIMEOUT" "$BOCO_BIN" boot "$img" --cmd 'echo RUN_OVERRIDE_OK; poweroff -f' 2>&1 || true)
check_output "$output" "RUN_OVERRIDE_OK" "$distro boot --cmd override"
"$SLIM_BIN" build qcow2 "$img" >/dev/null 2>&1
output=$(timeout "$TIMEOUT" "$SLIM_BIN" run "$img" --cmd 'echo RUN_OVERRIDE_OK; poweroff -f' 2>&1 || true)
check_output "$output" "RUN_OVERRIDE_OK" "$distro run --cmd override"
else
report fail "$distro boot --cmd override (podman build failed)"
report fail "$distro run --cmd override (podman build failed)"
fi
cleanup "$img" "$img"
# === Test 3: boco build --cmd override ===
echo "-- Test 3: boco build --cmd override"
# === Test 3: slim build --cmd override ===
echo "-- Test 3: slim build --cmd override"
cat > "$work/Containerfile.build" <<EOF
FROM $from
$extra_setup
CMD ["/bin/sh", "-c", "echo SHOULD_NOT_APPEAR; poweroff -f"]
EOF
img="boco-test-$distro-build"
img="slim-test-$distro-build"
if podman build -t "$img" -f "$work/Containerfile.build" >/dev/null 2>&1; then
"$BOCO_BIN" build qcow2 "$img" --cmd 'echo BUILD_OVERRIDE_OK; poweroff -f' >/dev/null 2>&1
output=$(timeout "$TIMEOUT" "$BOCO_BIN" boot "$img" 2>&1 || true)
"$SLIM_BIN" build qcow2 "$img" --cmd 'echo BUILD_OVERRIDE_OK; poweroff -f' >/dev/null 2>&1
output=$(timeout "$TIMEOUT" "$SLIM_BIN" run "$img" 2>&1 || true)
check_output "$output" "BUILD_OVERRIDE_OK" "$distro build --cmd override"
else
report fail "$distro build --cmd override (podman build failed)"
@@ -103,266 +102,11 @@ EOF
rm -rf "$work"
}
test_user() {
echo "=== Testing USER directive ==="
work="$(mktemp -d)"
img="boco-test-user"
cat > "$work/Containerfile" <<'EOF'
FROM alpine:latest
RUN adduser -D -u 1500 testuser
USER testuser
CMD ["/bin/sh", "-c", "echo USER_BUILD_OK:$(id -u):$(whoami); poweroff -f"]
EOF
echo "-- Building container image with USER directive..."
if ! podman build --network=none -t "$img" -f "$work/Containerfile" >/dev/null 2>&1; then
report fail "USER directive (podman build failed)"
rm -rf "$work"
return
fi
echo "-- Test 1: build-time CMD runs as USER"
"$BOCO_BIN" build qcow2 "$img" >/dev/null 2>&1
output=$(timeout "$TIMEOUT" "$BOCO_BIN" boot "$img" 2>&1 || true)
check_output "$output" "USER_BUILD_OK:1500:testuser" "USER build-time CMD runs as testuser"
echo "-- Test 2: boot --cmd override runs as USER"
output=$(timeout "$TIMEOUT" "$BOCO_BIN" boot "$img" --cmd 'echo USER_RUN_OK:$(id -u):$(whoami); poweroff -f' 2>&1 || true)
check_output "$output" "USER_RUN_OK:1500:testuser" "USER boot --cmd override runs as testuser"
cleanup "$img" "$img"
rm -rf "$work"
}
test_mount() {
echo "=== Testing --mount (9p shares) ==="
work="$(mktemp -d)"
# --- Image 1: no WORKINGDIR, test host:guest and multi-mount ---
img="boco-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 boco VM..."
if ! "$BOCO_BIN" build qcow2 "$img" >/dev/null 2>&1; then
report fail "--mount (boco 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 "$TIMEOUT" "$BOCO_BIN" boot "$img" \
--mount "${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: boco0" "--mount 9p share detected"
check_output "$output" "mount_tag: boco1" "--mount second 9p share detected"
check_output "$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" "$img"
# --- Image 2: with WORKINGDIR, test relative guest path ---
img="boco-test-mount-wd"
share_dir3="$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 boco VM..."
if ! "$BOCO_BIN" build qcow2 "$img" >/dev/null 2>&1; then
report fail "--mount relative (boco build failed)"
cleanup "$img" "$img"
rm -rf "$work"
return
fi
echo "-- Test 2: --mount host:relative-guest (resolved against WORKINGDIR)..."
output=$(timeout "$TIMEOUT" "$BOCO_BIN" boot "$img" \
--mount "${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 ==="
img="boco-test-nextcloud"
host_port=18080
work="$(mktemp -d)"
cat > "$work/Containerfile" <<'EOF'
FROM docker.io/library/nextcloud:32-apache
RUN apt-get update && apt-get install -y --no-install-recommends iproute2 && rm -rf /var/lib/apt/lists/*
EOF
echo "-- Building nextcloud container image..."
if ! podman build -t "$img" -f "$work/Containerfile" >/dev/null 2>&1; then
report fail "nextcloud service (podman build failed)"
rm -rf "$work"
return
fi
echo "-- Building boco VM..."
if ! "$BOCO_BIN" build qcow2 "$img" >/dev/null 2>&1; then
report fail "nextcloud service (boco build failed)"
cleanup "$img" "$img"
rm -rf "$work"
return
fi
echo "-- Booting VM with port forward (host :${host_port} -> guest :80)..."
setsid timeout 300 "$BOCO_BIN" boot "$img" \
--forward "tcp:0.0.0.0:${host_port}-:80" \
--memory 2048M >/dev/null 2>&1 &
vm_pid=$!
echo "-- Waiting for Nextcloud to start..."
up=0
for _ in $(seq 1 60); do
if curl -s -o /dev/null -m 2 "http://localhost:${host_port}/" 2>/dev/null; then
up=1
break
fi
sleep 3
done
if [ "$up" = "1" ]; then
response=$(curl -s -L -m 10 "http://localhost:${host_port}/" 2>/dev/null || true)
if echo "$response" | grep -qi "nextcloud"; then
report pass "nextcloud service (port forward + content)"
else
report fail "nextcloud service (port reachable but no 'nextcloud' in response)"
fi
else
report fail "nextcloud service (port not reachable within timeout)"
fi
pkill -f "qemu-system-x86_64.*$img" 2>/dev/null || true
kill "$vm_pid" 2>/dev/null || true
wait "$vm_pid" 2>/dev/null || true
cleanup "$img" "$img"
rm -rf "$work"
}
test_systemd() {
echo "=== Testing systemd as init ==="
work="$(mktemp -d)"
img="boco-test-systemd"
cat > "$work/boco-test.service" <<'SVC'
[Unit]
Description=boco systemd test
After=multi-user.target
[Service]
Type=oneshot
ExecStart=/bin/sh -c "echo SYSTEMD_TEST_OK > /dev/console; sleep 1; systemctl poweroff"
[Install]
WantedBy=multi-user.target
SVC
cat > "$work/Containerfile" <<EOF
FROM archlinux:latest
COPY boco-test.service /etc/systemd/system/boco-test.service
RUN mkdir -p /etc/systemd/system/multi-user.target.wants && \
ln -sf /etc/systemd/system/boco-test.service \
/etc/systemd/system/multi-user.target.wants/boco-test.service
CMD ["/sbin/init"]
EOF
echo "-- Building container image with systemd..."
if ! podman build -t "$img" "$work" >/dev/null 2>&1; then
report fail "systemd as init (podman build failed)"
rm -rf "$work"
return
fi
echo "-- Building boco VM..."
if ! "$BOCO_BIN" build qcow2 "$img" >/dev/null 2>&1; then
report fail "systemd as init (boco build failed)"
cleanup "$img" "$img"
rm -rf "$work"
return
fi
echo "-- Booting VM (systemd as PID 1)..."
output=$(timeout "$TIMEOUT" "$BOCO_BIN" boot "$img" 2>&1 || true)
check_output "$output" "SYSTEMD_TEST_OK" "systemd boots and runs service"
check_output "$output" "reboot: Power down" "systemd shuts down cleanly"
cleanup "$img" "$img"
rm -rf "$work"
}
echo "Building boco..."
echo "Building slim..."
cargo build 2>&1
cargo build --release -p boco-init --target x86_64-unknown-linux-musl 2>&1
cp "$TARGET_DIR/x86_64-unknown-linux-musl/release/boco-init" \
"${XDG_DATA_HOME:-$HOME/.local/share}/boco/boco-init"
test_distro "alpine" "alpine:latest" ""
test_distro "archlinux" "archlinux:latest" "RUN pacman -Sy --noconfirm iproute2 wget; pacman -Sc --noconfirm"
test_user
test_mount
test_service
test_systemd
test_distro "archlinux" "archlinux:latest" "RUN pacman -Sy --noconfirm iputils iproute2 util-linux; pacman -Sc --noconfirm"
echo ""
echo "=== Results: $pass passed, $fail failed ==="
-8
View File
@@ -1,8 +0,0 @@
[package]
name = "boco-init"
version = "0.1.0"
edition = "2024"
[dependencies]
base64 = "0.23"
nix = { version = "0.31", features = ["mount", "fs", "process", "user", "reboot"] }
-429
View File
@@ -1,429 +0,0 @@
//! boco universal init.
//!
//! Injected by `boco build` at /boco/init and invoked via init=/boco/init.
//! Sets up devices, filesystems, networking, and 9p shares, then execs the
//! container's CMD/ENTRYPOINT (or a runtime override) with execvp so the
//! command becomes PID 1 directly.
use base64::Engine;
use nix::mount::{MsFlags, mount};
use nix::sys::reboot::{RebootMode, reboot};
use nix::sys::stat::{Mode, SFlag, makedev, mknod};
use nix::sys::wait::waitpid;
use nix::unistd::{ForkResult, Gid, Uid, User, execvp, fork, setgid, setuid};
use std::env;
use std::ffi::CString;
use std::fs;
use std::os::unix::fs::PermissionsExt;
use std::path::Path;
use std::process::Command;
fn warn(msg: &str) {
eprintln!("boco-init: {msg}");
}
/// Run a fallible operation, logging on error.
fn try_io<F, T>(label: &str, f: F)
where
F: FnOnce() -> std::io::Result<T>,
{
if let Err(e) = f() {
warn(&format!("{label}: {e}"));
}
}
/// Run a command, logging on error or non-zero exit.
fn try_cmd(label: &str, cmd: &mut Command) {
match cmd.status() {
Ok(status) => {
if !status.success() {
warn(&format!("{label}: exited with {status}"));
}
}
Err(e) => warn(&format!("{label}: {e}")),
}
}
/// The kernel passes a minimal environment to init. Set a default PATH
/// so that `ip` and other tools can be found by name.
fn ensure_path() {
if env::var("PATH").is_err() {
// SAFETY: we are single-threaded before fork/exec.
unsafe {
env::set_var(
"PATH",
"/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
);
}
}
}
fn find_in_path(prog: &str) -> Option<String> {
let path = env::var("PATH").ok()?;
for dir in path.split(':') {
let candidate = format!("{dir}/{prog}");
if Path::new(&candidate).exists() {
return Some(candidate);
}
}
None
}
fn try_mount(
source: Option<&str>,
target: &str,
fstype: Option<&str>,
flags: MsFlags,
data: Option<&str>,
) {
if let Err(e) = mount(source, target, fstype, flags, data) {
warn(&format!("mount {target}: {e}"));
}
}
fn setup_filesystems() {
if !Path::new("/dev/console").exists() {
try_io("mknod /dev/console", || {
mknod(
"/dev/console",
SFlag::S_IFCHR,
Mode::S_IRUSR | Mode::S_IWUSR,
makedev(5, 1),
)
.map_err(std::io::Error::from)
});
}
let dirs = [
"/proc",
"/sys",
"/dev/pts",
"/dev/shm",
"/run",
"/tmp",
"/sys/fs/cgroup",
];
for d in &dirs {
try_io(&format!("mkdir {d}"), || fs::create_dir_all(d));
}
try_mount(Some("proc"), "/proc", Some("proc"), MsFlags::empty(), None);
try_mount(Some("sysfs"), "/sys", Some("sysfs"), MsFlags::empty(), None);
try_mount(
Some("devpts"),
"/dev/pts",
Some("devpts"),
MsFlags::empty(),
None,
);
try_mount(
Some("tmpfs"),
"/dev/shm",
Some("tmpfs"),
MsFlags::empty(),
None,
);
try_mount(
Some("tmpfs"),
"/run",
Some("tmpfs"),
MsFlags::empty(),
Some("mode=755"),
);
try_mount(
Some("tmpfs"),
"/tmp",
Some("tmpfs"),
MsFlags::empty(),
Some("mode=1777"),
);
// cgroup2
try_mount(
Some("cgroup2"),
"/sys/fs/cgroup",
Some("cgroup2"),
MsFlags::empty(),
None,
);
if let Ok(controllers) = fs::read_to_string("/sys/fs/cgroup/cgroup.controllers") {
for c in controllers.split_whitespace() {
try_io("write cgroup.subtree_control", || {
fs::write("/sys/fs/cgroup/cgroup.subtree_control", format!("+{c}"))
});
}
}
}
fn setup_rootless_prereqs() {
// make-rshared /
if let Err(e) =
mount::<str, str, str, str>(None, "/", None, MsFlags::MS_REC | MsFlags::MS_SHARED, None)
{
warn(&format!("make-rshared /: {e}"));
}
// chmod u+s newuidmap newgidmap
for bin in &["/usr/bin/newuidmap", "/usr/bin/newgidmap"] {
match fs::metadata(bin) {
Ok(meta) => {
let mut perms = meta.permissions();
perms.set_mode(perms.mode() | 0o4000);
try_io(&format!("chmod u+s {bin}"), || {
fs::set_permissions(bin, perms)
});
}
Err(e) if e.kind() == std::io::ErrorKind::NotFound => {}
Err(e) => warn(&format!("stat {bin}: {e}")),
}
}
}
fn setup_timezone() {
try_io("symlink timezone", || {
std::os::unix::fs::symlink("/usr/share/zoneinfo/Europe/Stockholm", "/etc/localtime")
});
}
fn setup_networking() {
let ip = find_in_path("ip").unwrap_or_else(|| "/sbin/ip".to_string());
try_cmd(
"ip link set lo up",
Command::new(&ip).args(["link", "set", "lo", "up"]),
);
try_cmd(
"ip link set eth0 up",
Command::new(&ip).args(["link", "set", "eth0", "up"]),
);
try_cmd(
"ip addr add 10.0.2.15/24 dev eth0",
Command::new(&ip).args(["addr", "add", "10.0.2.15/24", "dev", "eth0"]),
);
try_cmd(
"ip route add default via 10.0.2.2",
Command::new(&ip).args(["route", "add", "default", "via", "10.0.2.2"]),
);
try_io("write /etc/resolv.conf", || {
fs::write("/etc/resolv.conf", "nameserver 10.0.2.3\n")
});
}
fn setup_9p_shares(workdir: &str) {
let cmdline = match fs::read_to_string("/proc/cmdline") {
Ok(c) => c,
Err(e) => {
warn(&format!("read /proc/cmdline: {e}"));
return;
}
};
let b64 = base64::engine::general_purpose::STANDARD;
for tok in cmdline.split_whitespace() {
if let Some(rest) = tok.strip_prefix("boco.mount=") {
let Some((tag, dest_b64)) = rest.split_once(':') else {
continue;
};
let dest = match b64.decode(dest_b64) {
Ok(bytes) => match String::from_utf8(bytes) {
Ok(s) => s,
Err(e) => {
warn(&format!("9p: invalid UTF-8 in guest path: {e}"));
continue;
}
},
Err(e) => {
warn(&format!("9p: base64 decode failed: {e}"));
continue;
}
};
// Resolve relative guest paths against WORKINGDIR
let dest = if dest.starts_with('/') {
dest
} else {
format!("{}/{}", workdir, dest)
};
try_io(&format!("mkdir {dest}"), || fs::create_dir_all(&dest));
try_mount(
Some(tag),
&dest,
Some("9p"),
MsFlags::empty(),
Some("trans=virtio,version=9p2000.L"),
);
}
}
}
fn read_file_opt(path: &str) -> Option<String> {
fs::read_to_string(path)
.ok()
.filter(|s| !s.trim().is_empty())
}
fn split_null_delimited(data: &[u8]) -> Vec<String> {
data.split(|&b| b == 0)
.filter(|s| !s.is_empty())
.map(|s| String::from_utf8_lossy(s).into_owned())
.collect()
}
fn read_argv() -> Vec<String> {
// Check for runtime override: boco.cmd=<base64(null-delimited argv)>
let b64 = base64::engine::general_purpose::STANDARD;
if let Ok(cmdline) = fs::read_to_string("/proc/cmdline") {
for tok in cmdline.split_whitespace() {
if let Some(rest) = tok.strip_prefix("boco.cmd=")
&& let Ok(decoded) = b64.decode(rest)
{
let argv = split_null_delimited(&decoded);
if !argv.is_empty() {
return argv;
}
}
}
}
// Fall back to build-time argv from /boco/exec
match fs::read("/boco/exec") {
Ok(data) => {
let argv = split_null_delimited(&data);
if !argv.is_empty() {
return argv;
}
}
Err(e) => warn(&format!("read /boco/exec: {e}")),
}
warn("no command found, falling back to /bin/sh");
vec!["/bin/sh".to_string()]
}
fn apply_env() {
if let Ok(data) = fs::read("/boco/env") {
for entry in split_null_delimited(&data) {
if let Some((key, val)) = entry.split_once('=') {
// SAFETY: we are single-threaded before fork/exec.
unsafe { env::set_var(key, val) };
}
}
}
}
fn apply_workdir() {
if let Some(dir) = read_file_opt("/boco/workdir") {
try_io("set working directory", || env::set_current_dir(&dir));
}
}
struct UserSpec {
uid: Uid,
gid: Gid,
}
fn resolve_user(spec: &str) -> Option<UserSpec> {
let (user_part, gid_part) = match spec.split_once(':') {
Some((u, g)) => (u, Some(g)),
None => (spec, None),
};
let (uid, default_gid) = if let Ok(numeric) = user_part.parse::<u32>() {
let user = User::from_uid(Uid::from_raw(numeric)).ok().flatten();
let gid = user
.as_ref()
.map(|u| u.gid)
.unwrap_or(Gid::from_raw(numeric));
(Uid::from_raw(numeric), gid)
} else {
let user = User::from_name(user_part).ok().flatten()?;
(user.uid, user.gid)
};
let gid = match gid_part {
Some(g) => match g.parse::<u32>() {
Ok(n) => Gid::from_raw(n),
Err(_) => default_gid,
},
None => default_gid,
};
Some(UserSpec { uid, gid })
}
fn exec_command(argv: &[String], user: Option<UserSpec>) -> ! {
let cstrings: Vec<CString> = argv
.iter()
.map(|s| CString::new(s.as_str()).unwrap_or_default())
.collect();
let c_prog = cstrings[0].clone();
let c_refs: Vec<&CString> = cstrings.iter().collect();
match user {
None => {
// No privilege drop: exec directly, PID 1 becomes the command.
let Err(e) = execvp(&c_prog, &c_refs);
warn(&format!("execvp {}: {e}", argv[0]));
let _ = reboot(RebootMode::RB_POWER_OFF);
std::process::exit(1);
}
Some(user) => {
// Drop privileges in a child so PID 1 (root) can poweroff afterwards.
match unsafe { fork() } {
Ok(ForkResult::Child) => {
// setgid before setuid to avoid losing privileges
if let Err(e) = setgid(user.gid) {
warn(&format!("setgid: {e}"));
}
if let Err(e) = setuid(user.uid) {
warn(&format!("setuid: {e}"));
}
let Err(e) = execvp(&c_prog, &c_refs);
warn(&format!("execvp {}: {e}", argv[0]));
std::process::exit(127);
}
Ok(ForkResult::Parent { child }) => {
let _ = waitpid(child, None);
let _ = reboot(RebootMode::RB_POWER_OFF);
std::process::exit(0);
}
Err(e) => {
warn(&format!("fork: {e}"));
let _ = reboot(RebootMode::RB_POWER_OFF);
std::process::exit(1);
}
}
}
}
}
fn main() {
ensure_path();
// === Devices & special filesystems ===
setup_filesystems();
// === Rootless container prerequisites (best-effort) ===
setup_rootless_prereqs();
// === Timezone ===
setup_timezone();
// === Networking ===
setup_networking();
// === 9p shares ===
let workdir = read_file_opt("/boco/workdir").unwrap_or_default();
setup_9p_shares(&workdir);
// === Environment & working directory ===
apply_env();
apply_workdir();
// === Resolve user for privilege drop ===
let user = read_file_opt("/boco/user").and_then(|spec| resolve_user(&spec));
// === Execute the configured command ===
let argv = read_argv();
exec_command(&argv, user);
}
-4081
View File
File diff suppressed because it is too large Load Diff
Submodule kernel/linux deleted from 8d3ae59288
+20 -44
View File
@@ -1,4 +1,4 @@
//! Build: mount a podman image, inject /boco/ scripts, and pack the rootfs
//! Build: mount a podman image, inject /slim/ scripts, and pack the rootfs
//! as a gzipped cpio initrd or qcow2 disk in the registry.
use anyhow::{Context, Result, bail};
@@ -41,28 +41,19 @@ pub(crate) fn build(
}: BuildCmd,
) -> Result<()> {
let image = &name;
let container = format!("boco-build-{}", image.replace(':', "-"));
let mount_path = mount_container(image, &container)?;
let mount_path = mount_image(image)?;
println!("Mounted at: {}", mount_path.display());
let result = build_inner(&kind, image, &mount_path, cmd_override);
let unmounted = cmd(&[
"podman",
"unshare",
"--",
"podman",
"container",
"unmount",
&container,
"podman", "unshare", "--", "podman", "image", "unmount", image,
])
.is_ok();
let removed = cmd(&["podman", "rm", &container]).is_ok();
if unmounted && removed {
println!("Unmounted and removed container.");
if unmounted {
println!("Unmounted image.");
} else {
eprintln!("warning: failed to clean up container '{container}'");
eprintln!("warning: failed to unmount image '{}'", image);
}
result
@@ -75,18 +66,12 @@ fn build_inner(
cmd: Option<String>,
) -> Result<()> {
let config = inject::inspect_config(image)?;
let argv = match cmd {
Some(s) => vec!["/bin/sh".into(), "-c".into(), s],
None => inject::infer_argv(&config),
};
inject::inject(
mount_path,
&argv,
&config.env,
config.user.as_deref(),
config.working_dir.as_deref(),
)?;
println!("Injected /boco/ (init + exec)");
let command = cmd.unwrap_or_else(|| inject::infer_command(&config));
let env = inject::env(&config);
let working_dir = inject::working_dir(&config);
let exec_script = inject::build_exec_script(&command, &env, working_dir);
inject::inject(mount_path, &exec_script)?;
println!("Injected /slim/ (init + exec)");
match kind {
ImageKind::Initrd => build_initrd(image, mount_path),
@@ -94,22 +79,13 @@ fn build_inner(
}
}
fn mount_container(image: &str, container: &str) -> Result<PathBuf> {
cmd(&["podman", "create", "--name", container, image, "/bin/true"])?;
let mount_path = cmd(&[
"podman",
"unshare",
"--",
"podman",
"container",
"mount",
container,
])?;
fn mount_image(image: &str) -> Result<PathBuf> {
let mount_path = cmd(&["podman", "unshare", "--", "podman", "image", "mount", image])?;
Ok(PathBuf::from(mount_path.trim()))
}
/// Copy a directory onto a new raw disk image with EXT4.
fn to_raw_ext4(dir: &Path, tmp_dir: &Path) -> Result<NamedTempFile> {
fn to_raw_ext4(dir: &Path) -> Result<NamedTempFile> {
let dir = dir.to_str().context("Invalid UTF-8")?;
let du_out = cmd(&["podman", "unshare", "--", "du", "-sk", dir])?;
@@ -127,7 +103,7 @@ fn to_raw_ext4(dir: &Path, tmp_dir: &Path) -> Result<NamedTempFile> {
+ 64 * gb; // Add some spare capacity for activities
let size = size.to_string();
let raw_file = NamedTempFile::new_in(tmp_dir)?;
let raw_file = NamedTempFile::new()?;
let raw_path = raw_file.path().to_str().context("Invalid UTF-8")?;
cmd(&["podman", "unshare", "--", "truncate", "-s", &size, raw_path])?;
cmd(&[
@@ -144,9 +120,9 @@ fn to_raw_ext4(dir: &Path, tmp_dir: &Path) -> Result<NamedTempFile> {
}
/// Copy a directory onto a new qcow2 disk image with EXT4.
fn to_qcow2_ext4(mount_path: &Path, tmp_dir: &Path) -> Result<NamedTempFile> {
let raw = to_raw_ext4(mount_path, tmp_dir)?;
let qcow2 = NamedTempFile::new_in(tmp_dir)?;
fn to_qcow2_ext4(mount_path: &Path) -> Result<NamedTempFile> {
let raw = to_raw_ext4(mount_path)?;
let qcow2 = NamedTempFile::new()?;
let raw_path = raw.path().to_str().context("Invalid UTF-8")?;
let qcow2_path = qcow2.path().to_str().context("Invalid UTF-8")?;
cmd(&[
@@ -160,7 +136,7 @@ fn build_qcow2(image: &str, mount_path: &Path) -> Result<()> {
fs::create_dir_all(&reg_dir)?;
println!("Registry: {}", reg_dir.display());
let qcow2 = to_qcow2_ext4(mount_path, &reg_dir)?;
let qcow2 = to_qcow2_ext4(mount_path)?;
fs::copy(qcow2.path(), reg_dir.join("image.qcow2"))
.context("Failed to copy qcow2 image to registry")?;
+84 -65
View File
@@ -1,6 +1,5 @@
//! Inject: inspect a podman image's config, infer the default command argv,
//! and inject the boco init binary + null-delimited argv/env files into the
//! mounted rootfs.
//! Inject: inspect a podman image's config, infer the default command, and
//! inject distro-agnostic /slim/ scripts (init + exec) into the mounted rootfs.
use anyhow::{Context, Result, anyhow};
use serde::Deserialize;
@@ -8,21 +7,20 @@ use std::fs;
use std::path::Path;
use crate::command::cmd;
use crate::registry::init_binary_path;
const SLIM_INIT: &str = include_str!("scripts/slim-init.sh");
#[derive(Debug, Default, Deserialize)]
#[serde(rename_all = "PascalCase")]
pub struct Config {
#[serde(default)]
pub cmd: Vec<String>,
cmd: Option<Vec<String>>,
#[serde(default)]
pub entrypoint: Vec<String>,
entrypoint: Option<Vec<String>>,
#[serde(default)]
pub env: Vec<String>,
env: Option<Vec<String>>,
#[serde(default)]
pub working_dir: Option<String>,
#[serde(default)]
pub user: Option<String>,
working_dir: Option<String>,
}
pub fn inspect_config(image: &str) -> Result<Config> {
@@ -39,77 +37,98 @@ pub fn inspect_config(image: &str) -> Result<Config> {
Ok(config)
}
/// Infer the command argv from the image config.
/// Infer the command string from the image config.
///
/// Concatenates ENTRYPOINT + CMD (Docker semantics). If neither is present,
/// falls back to `["/bin/sh"]`.
pub fn infer_argv(config: &Config) -> Vec<String> {
let parts: Vec<String> = config
.entrypoint
.iter()
.chain(config.cmd.iter())
.cloned()
.collect();
/// falls back to `/bin/sh`.
pub fn infer_command(config: &Config) -> String {
let entrypoint = config.entrypoint.as_deref().filter(|e| !e.is_empty());
let cmd = config.cmd.as_deref().filter(|c| !c.is_empty());
if parts.is_empty() {
vec!["/bin/sh".into()]
} else {
let parts: Vec<String> = match (entrypoint, cmd) {
(Some(ep), Some(c)) => {
let mut parts = ep.to_vec();
parts.extend(c.iter().cloned());
parts
}
(Some(ep), None) => ep.to_vec(),
(None, Some(c)) => c.to_vec(),
(None, None) => vec!["/bin/sh".to_string()],
};
if parts.len() == 3 && (parts[0] == "/bin/sh" || parts[0] == "sh") && parts[1] == "-c" {
parts[2].clone()
} else {
shell_join(&parts)
}
}
/// Join items as null-delimited bytes.
pub fn null_delimited(items: &[String]) -> Vec<u8> {
let mut data = Vec::new();
for item in items {
data.extend_from_slice(item.as_bytes());
data.push(0);
}
data
pub fn env(config: &Config) -> Vec<String> {
config.env.clone().unwrap_or_default()
}
/// Install `content` into the mounted rootfs at `<mount>/boco/<name>` with
/// the given mode.
fn install_into_rootfs(mount: &str, name: &str, mode: &str, content: &[u8]) -> Result<()> {
let temp = tempfile::NamedTempFile::new()?;
fs::write(temp.path(), content)?;
let src = temp.path().to_str().context("temp path is not UTF-8")?;
let dest = format!("{mount}/boco/{name}");
cmd(&[
"podman", "unshare", "--", "install", "-D", "-m", mode, src, &dest,
])?;
Ok(())
pub fn working_dir(config: &Config) -> Option<&str> {
config.working_dir.as_deref()
}
/// Inject /boco/init (binary), /boco/exec (null-delimited argv), /boco/env
/// (null-delimited env), and optionally /boco/user and /boco/workdir into a
/// mounted container image rootfs.
pub fn inject(
mount_path: &Path,
argv: &[String],
env: &[String],
user: Option<&str>,
working_dir: Option<&str>,
) -> Result<()> {
fn shell_escape(s: &str) -> String {
format!("'{}'", s.replace('\'', "'\\''"))
}
fn shell_join(parts: &[String]) -> String {
parts
.iter()
.map(|p| shell_escape(p))
.collect::<Vec<_>>()
.join(" ")
}
/// Generate the /slim/exec script from a command string, env vars, and working dir.
pub fn build_exec_script(command: &str, env: &[String], working_dir: Option<&str>) -> String {
let mut lines = String::from("#!/bin/sh\n");
if let Some(dir) = working_dir.filter(|d| !d.is_empty()) {
lines.push_str(&format!("cd {} 2>/dev/null\n", shell_escape(dir)));
}
for var in env {
if let Some((key, val)) = var.split_once('=') {
lines.push_str(&format!(
"export {}={}\n",
shell_escape(key),
shell_escape(val)
));
}
}
lines.push_str(&format!("exec /bin/sh -c {}\n", shell_escape(command)));
lines
}
/// Inject /slim/init and /slim/exec into a mounted container image rootfs.
pub fn inject(mount_path: &Path, exec_script: &str) -> Result<()> {
let mount_str = mount_path.to_str().context("mount path is not UTF-8")?;
let init_binary = fs::read(init_binary_path()?).context("Failed to read boco-init binary")?;
let exec_data = null_delimited(argv);
let env_data = null_delimited(env);
let init_temp = tempfile::NamedTempFile::new()?;
let exec_temp = tempfile::NamedTempFile::new()?;
fs::write(init_temp.path(), SLIM_INIT)?;
fs::write(exec_temp.path(), exec_script)?;
install_into_rootfs(mount_str, "init", "755", &init_binary)?;
install_into_rootfs(mount_str, "exec", "644", &exec_data)?;
if !env_data.is_empty() {
install_into_rootfs(mount_str, "env", "644", &env_data)?;
}
let init_src = init_temp
.path()
.to_str()
.context("temp path is not UTF-8")?;
let exec_src = exec_temp
.path()
.to_str()
.context("temp path is not UTF-8")?;
if let Some(user) = user.filter(|u| !u.is_empty()) {
install_into_rootfs(mount_str, "user", "644", user.as_bytes())?;
}
let init_dest = format!("{mount_str}/slim/init");
let exec_dest = format!("{mount_str}/slim/exec");
if let Some(dir) = working_dir.filter(|d| !d.is_empty()) {
install_into_rootfs(mount_str, "workdir", "644", dir.as_bytes())?;
}
cmd(&[
"podman", "unshare", "--", "install", "-D", "-m", "755", init_src, &init_dest,
])?;
cmd(&[
"podman", "unshare", "--", "install", "-D", "-m", "755", exec_src, &exec_dest,
])?;
Ok(())
}
+5 -5
View File
@@ -9,7 +9,7 @@ mod registry;
use anyhow::Result;
use clap::{Parser, Subcommand};
use crate::{build::BuildCmd, image::ImageCmd, qemu::BootCmd};
use crate::{build::BuildCmd, image::ImageCmd, qemu::RunCmd};
#[derive(Parser, Debug)]
#[command(about = "Turn containers into bootable VMs")]
@@ -23,8 +23,8 @@ enum Commands {
/// Build initrd from an image (podman image must exist)
Build(BuildCmd),
/// Launch a previously built VM via QEMU.
Boot(BootCmd),
/// List boco images in the registry
Run(RunCmd),
/// List slim images in the registry
#[command(subcommand)]
Image(ImageCmd),
}
@@ -35,8 +35,8 @@ fn main() -> Result<()> {
Commands::Build(cmd) => {
build::build(cmd)?;
}
Commands::Boot(cmd) => {
qemu::boot(cmd)?;
Commands::Run(cmd) => {
qemu::run(cmd)?;
}
Commands::Image(cmd) => {
image::run(cmd)?;
+12 -52
View File
@@ -1,8 +1,8 @@
//! QEMU: boot a registry entry with qemu-system-x86_64 using direct kernel
//! boot (-kernel/-initrd or -drive). The kernel is shared across all VMs
//! at $XDG_DATA_HOME/boco/registry/vmlinuz. A universal /boco/init script (injected
//! at build time) handles VM bootstrap; /boco/exec runs the container's
//! CMD/ENTRYPOINT. Runtime overrides are delivered as `boco.cmd=<base64>`
//! at $XDG_DATA_HOME/slim-rs/vmlinuz. A universal /slim/init script (injected
//! at build time) handles VM bootstrap; /slim/exec runs the container's
//! CMD/ENTRYPOINT. Runtime overrides are delivered as `slim.cmd=<base64>`
//! on the kernel cmdline.
use anyhow::{Context, Result, bail};
@@ -16,7 +16,7 @@ use crate::{
};
#[derive(Args, Debug)]
pub struct BootCmd {
pub struct RunCmd {
/// Image tag / registry subdir name
name: String,
@@ -29,26 +29,18 @@ pub struct BootCmd {
forward: Vec<PortForward>,
/// Override the command to exec in the VM (base64-encoded on the kernel
/// cmdline as boco.cmd=<b64>). Overrides the CMD inferred at build time.
/// cmdline as slim.cmd=<b64>). Overrides the CMD inferred at build time.
#[clap(long)]
cmd: Option<String>,
/// Share a host directory into the VM via 9p. Format:
/// `<host-path>` or `<host-path>:<guest-path>`. 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<String>,
}
pub(crate) fn boot(
BootCmd {
pub(crate) fn run(
RunCmd {
name,
memory,
forward,
cmd,
mount,
}: BootCmd,
}: RunCmd,
) -> Result<()> {
let reg_dir = registry_dir(&name)?;
let vmlinuz_path = registry_base_dir()?.join("vmlinuz");
@@ -67,7 +59,7 @@ pub(crate) fn boot(
"rw".into(),
"earlyprintk=serial".into(),
"nokaslr".into(),
"init=/boco/init".into(),
"init=/slim/init".into(),
"devtmpfs.mount=1".into(), // Automatically mount /dev at boot
];
@@ -81,43 +73,12 @@ pub(crate) fn boot(
fs_args = vec!["-initrd".to_string(), initrd_str];
cmdline.push("root=/dev/ram0".into());
} else {
bail!("Registry missing rootfs/initrd for '{name}'. Run `boco build` first.");
bail!("Registry missing rootfs/initrd for '{name}'. Run `slim build` first.");
}
if let Some(cmd) = &cmd {
let argv = ["/bin/sh".to_string(), "-c".to_string(), cmd.clone()];
let data: Vec<u8> = argv.join("\0").into_bytes();
let encoded = base64::engine::general_purpose::STANDARD.encode(&data);
cmdline.push(format!("boco.cmd={encoded}"));
}
// Build 9p shares for each --mount. Tags are short (boco0, boco1, …)
// because 9p mount_tag has a ~31-byte limit. The guest destination path
// is passed on the kernel cmdline as boco.mount=<tag>:<base64(guest_path)>.
// If no guest path is specified, the host path is used as the guest path.
let mut virtfs_args: Vec<String> = 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!("boco{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!("boco.mount={tag}:{dest_b64}"));
let encoded = base64::engine::general_purpose::STANDARD.encode(cmd.as_bytes());
cmdline.push(format!("slim.cmd={encoded}"));
}
println!("Booting {name} from registry: {}", reg_dir.display());
@@ -140,7 +101,6 @@ pub(crate) fn boot(
.arg("-kernel")
.arg(vmlinuz_path.as_os_str())
.args(&fs_args)
.args(&virtfs_args)
.args(["-snapshot"])
.args(["-no-reboot"])
.args(["-append", &cmdline])
+4 -10
View File
@@ -1,12 +1,12 @@
//! Registry: local storage of built VM artifacts under
//! `$XDG_DATA_HOME/boco/registry/<image>/`.
//! `$XDG_DATA_HOME/slim-rs/registry/<image>/`.
use anyhow::{Context, Result, anyhow, bail};
use std::{fs, io, path::PathBuf};
/// Validate a user-supplied image name before it is used in a registry path.
///
/// The name becomes a directory under `$XDG_DATA_HOME/boco/registry/`, so
/// The name becomes a directory under `$XDG_DATA_HOME/slim-rs/registry/`, so
/// path separators and `.`/`..` would allow escaping that directory.
/// Allow-list: ASCII alphanumerics plus `.`, `_`, `:`, `-` (covers image
/// refs like `alpine:3.15`).
@@ -27,17 +27,11 @@ pub(crate) fn validate_image_name(name: &str) -> Result<()> {
}
pub(crate) fn registry_base_dir() -> Result<PathBuf> {
let base = xdg::BaseDirectories::with_prefix("boco");
let base = xdg::BaseDirectories::with_prefix("slim-rs");
base.create_data_directory("registry")
.context("Failed to create XDG_DATA_HOME subdirectory")
}
pub(crate) fn init_binary_path() -> Result<PathBuf> {
let base = xdg::BaseDirectories::with_prefix("boco");
base.get_data_file("boco-init")
.context("boco-init not found in XDG data dir")
}
pub(crate) fn registry_dir(image: &str) -> Result<PathBuf> {
validate_image_name(image)?;
let base = registry_base_dir()?;
@@ -62,7 +56,7 @@ mod tests {
fn accepts_valid_image_names() {
for name in [
"alpine:3.15",
"boco",
"slim",
"mock-vm",
"my_vm",
"a.b.c",
+54
View File
@@ -0,0 +1,54 @@
#!/bin/sh
# slim universal init - distro-agnostic VM bootstrap.
# Injected by `slim build` at /slim/init and invoked via init=/slim/init.
# === Devices & special filesystems ===
[ -c /dev/console ] || mknod -m 600 /dev/console c 5 1
mkdir -p /proc /sys /dev/pts /dev/shm
mount -t proc proc /proc
mount -t sysfs sysfs /sys
mount -t devpts devpts /dev/pts
mount -t tmpfs tmpfs /dev/shm
mount -t tmpfs tmpfs /run -o mode=755
mount -t tmpfs tmpfs /tmp -o mode=1777
# === cgroup2 ===
mkdir -p /sys/fs/cgroup
mount -t cgroup2 none /sys/fs/cgroup 2>/dev/null || echo "mount cgroup2 failed"
# shellcheck disable=SC2013 # word-splitting is intentional: controllers are space-separated
for c in $(cat /sys/fs/cgroup/cgroup.controllers 2>/dev/null); do
echo "+$c" > /sys/fs/cgroup/cgroup.subtree_control 2>/dev/null || echo "enable cgroup controller $c failed"
done
# === Rootless container prerequisites (best-effort) ===
mount --make-rshared / 2>/dev/null || echo "make-rshared / failed"
chmod u+s /usr/bin/newuidmap /usr/bin/newgidmap 2>/dev/null || echo "chmod newuidmap/newgidmap failed"
# === Timezone ===
ln -sf /usr/share/zoneinfo/Europe/Stockholm /etc/localtime 2>/dev/null || echo "set timezone failed"
# === Networking (QEMU slirp: guest 10.0.2.15/24, gw 10.0.2.2, dns 10.0.2.3) ===
ip link set lo up 2>/dev/null || echo "ip link set lo up failed"
ip link set eth0 up 2>/dev/null || echo "ip link set eth0 up failed"
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
# === Execute the configured command ===
# If slim.cmd=<base64> is on the kernel cmdline, decode and exec it.
# Otherwise, exec /slim/exec (generated from the image's CMD/ENTRYPOINT).
# 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.cmd=*)
v=${tok#slim.cmd=}
decoded=$(printf '%s' "$v" | base64 -d 2>/dev/null) \
|| decoded=$(printf '%s' "$v" | openssl base64 -d 2>/dev/null) \
|| echo "base64 decode failed"
if [ -n "$decoded" ]; then
exec /bin/sh -c "$decoded"
fi
;;
esac
done
exec /slim/exec