create-freebsd-dev-env

Create a FreeBSD dev/test VM for ponyc

Stand up a local FreeBSD VM that matches the ponyc tier-3 CI job, so you can build and test ponyc on FreeBSD without GitHub Actions.

FreeBSD's tier-3 job exercises paths the clang-on-Linux jobs never do: the embedded-LLD --static link recipe, the native sanitizer link path, the dtrace/illumos provider path, and FreeBSD's base libc++/libunwind. So this VM is the authoritative local environment for FreeBSD-platform ponyc issues. (It is clang-based — FreeBSD's base compiler is clang, not gcc. For gcc-specific issues use the DragonFly skill instead.)

Run the repo-relative commands (rsync of the source) from your ponyc checkout root. The VM itself lives in a separate directory ($VMDIR).

Each fenced sh block below is self-contained. It re-sets VMDIR/FREEBSD_VERSION (and, where needed, the SSH command) at its top, because an agent runs each block as a fresh shell — environment variables and the working directory do NOT carry from one block to the next. Do not "optimize" by setting them once and dropping them from later blocks: an empty $SSH would make a $SSH /bin/sh <<'EOF' ... EOF heredoc run on your host (silently) instead of in the VM. Keep every block whole. Pick your VMDIR/ FREEBSD_VERSION once and use the same values in every block.

Gotchas that will bite you (read first)

FreeBSD is much simpler to bring up than DragonFly (cloud-init injects the ssh key, so there is no VGA-console automation), but these still matter:

• Per-block fresh shells. See above: re-establish VMDIR/FREEBSD_VERSION/SSH in every block; never let $SSH be empty in front of a /bin/sh heredoc.
• You log in as freebsd, not root. The cloud-init seed installs your key for the freebsd user and sets root's password to ciroot. Build and test run as freebsd (no root needed). Root is only needed twice during setup — the one-time expect/su bootstrap below installs the packages and configures passwordless doas, after which the rare root operation (e.g. loading the dtrace kernel module) goes through doas.
• Cloud-init means no console driving. Unlike the DragonFly skill there is no QEMU sendkey/screendump/monitor dance — just boot and wait for ssh. But the first boot runs nuageinit (key install) and growfs (root-fs auto-resize), so ssh is not instant; poll for it (Step 4).
• The root fs auto-grows; there is no growfs command to run. qemu-img resize ... 60G enlarges the disk and the image's first boot grows the root fs to fill it. You do not run growfs yourself — the wait-for-ssh loop is what accounts for it.
• FreeBSD's base system has no bash. In-VM scripts must be POSIX sh (the two CI smoke scripts already are). Don't reach for bashisms in a $SSH /bin/sh heredoc.
• Detach long in-VM builds. The libs build (LLVM) takes hours; run it nohup … > /…/x.log 2>&1 & and poll the log, so an ssh drop doesn't kill it.
• The one-time root bootstrap needs expect. FreeBSD's nuageinit supports only ssh_authorized_keys + chpasswd (not cloud-init's write_files/runcmd), so the package install and doas.conf setup are driven through su -m root with expect, exactly as CI does it. After that, doas is on disk and persists across reboots.

Step 0 — verify prerequisites (do NOT assume they're installed)

This skill needs, on the host:

• an existing ponyc checkout (you run the rsync from it)
• hardware-accelerated virtualization for QEMU (KVM on Linux, HVF on macOS)
• enough free disk for the VM's sparse qcow2 disk (provisioned at 60 GB nominal; it grows only as used — the libs build plus a debug build take the qcow2 to ~12 GB, and a release build on top adds more), ~1 GB for the compressed image, and network access to download.freebsd.org
• qemu-system-x86_64 and qemu-img
• cloud-localds (from cloud-image-utils) or genisoimage to build the cloud-init seed image
• expect (drives the one-time su root bootstrap)
• xz, rsync, git, curl, python3
• an OpenSSH client (ssh, scp, ssh-keygen)

Note this list is shorter than the DragonFly skill's: FreeBSD needs no bsdtar/bunzip2 (no ISO header mining) and no PPM-to-PNG converter (no console screendumps).

Check that every required tool is present. Do not assume the environment has them, and do not install anything yourself — installing them is the user's call (it needs privilege, and the package names vary by OS). If anything is missing, stop, tell the user which tools/capabilities are missing, and ask them to install them with their platform's package manager, then re-run the check before proceeding.

missing=""
for t in qemu-system-x86_64 qemu-img expect xz rsync git ssh scp ssh-keygen curl python3; do
  command -v "$t" >/dev/null 2>&1 || missing="$missing $t"
done
command -v cloud-localds >/dev/null 2>&1 || command -v genisoimage >/dev/null 2>&1 \
  || missing="$missing seed-builder(cloud-localds|genisoimage)"
# Hardware acceleration is host-specific — check the right accelerator for this OS.
case "$(uname -s)" in
  Linux)  [ -w /dev/kvm ] || missing="$missing kvm(/dev/kvm-not-writable)" ;;
  Darwin) qemu-system-x86_64 -accel help 2>&1 | grep -q hvf || missing="$missing hvf-accelerator" ;;
  *)      echo "NOTE: confirm this host has a QEMU hardware accelerator and adjust the boot accel= below" ;;
esac
[ -n "$missing" ] && echo "MISSING:$missing" || echo "all prerequisites present"

If the output is anything but all prerequisites present, name the missing tools/capabilities to the user and ask them to install them however their OS does — do NOT guess a distro package name. (cloud-localds ships in cloud-image-utils on Debian/Ubuntu; if it is unavailable, the cidata seed can also be built with genisoimage -output seed.img -volid cidata -joliet -rock user-data meta-data, which is what the OpenBSD CI path uses.) A missing hardware accelerator — no writable /dev/kvm on Linux, no HVF on macOS — is a host/BIOS/virtualization fix only the user can make; the VM is unusably slow without it, so don't fall back to TCG emulation.

This flow is verified on Linux+KVM through the libs build and a debug build. The guest side is OS-agnostic, so macOS goes through the same steps with the HVF accelerator (accel=kvm:hvf in Step 3 selects it).

Setup

Pick a persistent VM directory and a FreeBSD version that matches ponyc CI (the tier-3 freebsd job in .github/workflows/ponyc-tier3.yml tests a single version — currently 15.1; the image URL is in .ci-scripts/bsd/freebsd-provision.bash). Use the same value in every block below.

1. Download the image (one time; keep the .xz to avoid re-downloading)

The BASIC-CLOUDINIT image boots straight to a cloud-init-configured system — no installer, and it ships the full base system including /usr/include.

VMDIR=~/vms/freebsd-15.1; FREEBSD_VERSION=15.1
mkdir -p "$VMDIR" && cd "$VMDIR"
base="https://download.freebsd.org/releases/VM-IMAGES/${FREEBSD_VERSION}-RELEASE/amd64/Latest"
curl -fL --retry 3 -o freebsd.qcow2.xz \
  "$base/FreeBSD-${FREEBSD_VERSION}-RELEASE-amd64-BASIC-CLOUDINIT-ufs.qcow2.xz"
xz -dk freebsd.qcow2.xz                 # -k keeps the .xz original
qemu-img resize freebsd.qcow2 60G       # first boot grows the root fs to fill this

2. Key + cloud-init seed

nuageinit reads a cidata seed image at boot: it installs your ssh public key for the freebsd user and sets root's password (so the Step 5 su bootstrap can reach root).

VMDIR=~/vms/freebsd-15.1; cd "$VMDIR"
test -f vm_key || ssh-keygen -t ed25519 -f vm_key -N "" -q
cat > user-data <<USERDATA
#cloud-config
ssh_authorized_keys:
  - $(cat vm_key.pub)
chpasswd:
  expire: false
  list:
    - root:ciroot
USERDATA
cat > meta-data <<'METADATA'
instance-id: freebsd-dev
local-hostname: freebsd-dev
METADATA
cloud-localds seed.img user-data meta-data

3. Boot (daemonized, persistent)

VMDIR=~/vms/freebsd-15.1; FREEBSD_VERSION=15.1; cd "$VMDIR"
qemu-system-x86_64 \
  -name freebsd-${FREEBSD_VERSION} \
  -machine pc,accel=kvm:hvf -cpu host -smp 8 -m 12G \
  -drive file=freebsd.qcow2,format=qcow2,if=virtio \
  -drive file=seed.img,format=raw,if=virtio \
  -netdev user,id=net0,hostfwd=tcp::2222-:22 \
  -device virtio-net-pci,netdev=net0 \
  -display none -pidfile freebsd.pid -daemonize

(accel=kvm:hvf picks KVM on Linux or HVF on macOS and errors if neither is available — it never silently falls back to slow TCG. -smp/-m are speed knobs; CI uses 4 CPUs / 12G. hostfwd 2222->22 is the ssh port — to run two FreeBSD VMs at once (e.g. CI's 15.1 plus another version you want to compare against), give each its own $VMDIR and a distinct hostfwd port, and pass that port to every ssh/scp/rsync -p. The seed drive stays attached — nuageinit skips it on later boots once the instance-id is seen. This boot command is adapted from .ci-scripts/bsd/freebsd-provision.bash: it adds -pidfile/-smp 8 and drops the CI host-bootstrap; CI has no rng or monitor device for FreeBSD and neither does this.)

4. Wait for ssh (first boot runs nuageinit + growfs)

VMDIR=~/vms/freebsd-15.1; FREEBSD_VERSION=15.1; cd "$VMDIR"
up=""
for i in $(seq 1 150); do   # ~5 min, matching CI's timeout
  if ssh -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -o LogLevel=ERROR -o ConnectTimeout=2 -i vm_key -p 2222 \
       freebsd@localhost true 2>/dev/null; then up=1; echo "SSH up"; break; fi
  sleep 2
done
[ -n "$up" ] || echo "SSH NEVER CAME UP — see recovery below."

If ssh never comes up, this VM has no VGA console to look at (it booted headless), so diagnose in this order:

• Is the process alive? pgrep -af "qemu-system-x86_64 -name freebsd-${FREEBSD_VERSION}". If it's gone, the boot died early (usually a bad/incomplete image from Step 1) — re-check the Step 1 download/resize and re-boot.
• Watch the boot. The image logs to the serial console, so re-boot with a serial log added — kill "$(cat freebsd.pid)", then re-run the Step 3 boot command with -serial file:$VMDIR/console.log appended — and read console.log to see how far it got.
• ssh actively refuses the key (vs. just timing out)? That means nuageinit never installed it — the seed didn't apply. Confirm seed.img is attached as a drive in the boot command (Step 3) and was built in Step 2, then re-boot.

5. One-time root bootstrap (install deps + configure doas) via expect

FreeBSD's nuageinit can't run write_files/runcmd, so — exactly as CI does — drive su -m root with expect to install the build dependencies and grant the freebsd user passwordless doas. This runs once; doas.conf persists on disk for the VM's life. (The expect block is adapted from the one embedded in freebsd-provision.bash.)

VMDIR=~/vms/freebsd-15.1; cd "$VMDIR"
expect <<'EXPECT'
set timeout 600
spawn ssh -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -o LogLevel=ERROR -i vm_key -p 2222 -t freebsd@localhost su -m root
expect {
  "Password:" { send "ciroot\r" }
  timeout { puts "Timeout waiting for password prompt"; exit 1 }
}
expect {
  "su: Sorry" { puts "su failed - wrong password or nuageinit didn't set it"; exit 1 }
  "#" {}
  timeout { puts "Timeout waiting for root shell"; exit 1 }
}
send "pkg install -y cmake gmake libunwind git python3 rsync doas\r"
expect {
  "#" {}
  timeout { puts "Timeout during pkg install"; exit 1 }
}
send "echo 'permit nopass freebsd' > /usr/local/etc/doas.conf\r"
expect {
  "#" {}
  timeout { puts "Timeout writing doas.conf"; exit 1 }
}
send "exit\r"
expect eof
EXPECT

If expect prints one of its Timeout … messages, it's safe to re-run this block — the pkg install -y and the clobbering > write to doas.conf are both idempotent. The one exception is su failed: that means the seed never set root's password, so root was never reachable. Re-running won't fix it — that's a boot/seed problem, so work through the Step 4 recovery (is the VM up? did seed.img apply?) first.

6. Rsync the ponyc checkout in (exclude the host build/)

Run from your ponyc checkout. Exclude the top-level build/ (host artifacts; the VM builds its own). Keep .git (CMake runs git rev-parse). The vendored LLVM submodule under lib/llvm/src IS transferred — the VM needs it for the libs build.

VMDIR=~/vms/freebsd-15.1
rsync -az --exclude='/build' \
  -e "ssh -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -o LogLevel=ERROR -i $VMDIR/vm_key -p 2222" \
  "$(git rev-parse --show-toplevel)/" freebsd@localhost:/home/freebsd/ponyc/

Using the VM

The build uses FreeBSD's default clang — no CC/CXX/LD_LIBRARY_PATH exports (that is the DragonFly-only gcc13 dance). cmake -P lib/build-libs.cmake builds the vendored LLVM and is the multi-hour long pole — run it detached, then poll the log until it ends with libs DONE rc=0 (a nonzero rc means it failed — read the log above the marker):

VMDIR=~/vms/freebsd-15.1
SSH="ssh -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -o LogLevel=ERROR -i $VMDIR/vm_key -p 2222 freebsd@localhost"
$SSH /bin/sh <<'EOF'
set -e
cat > /home/freebsd/run-libs.sh <<'S'
#!/bin/sh
cd /home/freebsd/ponyc && cmake -DJOBS=8 -P lib/build-libs.cmake
echo "libs DONE rc=$?"
S
chmod +x /home/freebsd/run-libs.sh
nohup /home/freebsd/run-libs.sh > /home/freebsd/libs-build.log 2>&1 &
echo "libs building pid $!"
EOF
# poll until done: $SSH /bin/sh -c 'tail -3 /home/freebsd/libs-build.log'  -> wait for "libs DONE rc=0"

Once libs is built (it persists in the VM), build and test with the same shell. Do not run this block until the poll shows libs DONE rc=0 — cmake --build against a half-built build/libs fails:

VMDIR=~/vms/freebsd-15.1
SSH="ssh -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -o LogLevel=ERROR -i $VMDIR/vm_key -p 2222 freebsd@localhost"
$SSH /bin/sh <<'EOF'
set -e
cd /home/freebsd/ponyc
cmake --preset debug
cmake --build --preset debug
ctest --preset debug -L ci-core
EOF

To iterate on a fix: edit on the host, re-run Step 6's rsync (it's incremental — only changed files are sent), then re-run the build block above (long rebuilds should also be detached + polled). For exact CI parity, the tier-3 freebsd job (.github/workflows/ponyc-tier3.yml) runs more than this — a --static embedded-LLD link smoke, the self-hosted tool tests (pony-doc-tests/pony-lint-tests/pony-lsp-tests), a release build + the ci-core suite, and two extra smokes: .ci-scripts/freebsd-sanitizer-smoke.sh and .ci-scripts/freebsd-dtrace-smoke.sh (the dtrace one needs the doas configured in Step 5). Consult that job when validating a CI-matching issue.

Lifecycle

VMDIR=~/vms/freebsd-15.1; FREEBSD_VERSION=15.1; cd "$VMDIR"
pgrep -af "qemu-system-x86_64 -name freebsd-${FREEBSD_VERSION}"        # status
ssh -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -o LogLevel=ERROR -i vm_key -p 2222 freebsd@localhost   # interactive shell
# stop: CI stops this VM by killing the process; do the same. Disks persist for next time.
# The pgrep/pkill are scoped to this version so a second FreeBSD VM (e.g. another
# version you're comparing against) isn't matched; the pidfile path is per-$VMDIR anyway.
kill "$(cat freebsd.pid)" 2>/dev/null || pkill -f "qemu-system-x86_64 -name freebsd-${FREEBSD_VERSION}"

To restart later, re-run the step-3 boot command (the disk and installed deps persist; you do not redo setup). On a reboot, ssh-as-freebsd works immediately (the key was written to disk on first boot) and doas still works (doas.conf persisted) — there is no re-bootstrap, unlike the DragonFly VM.

How this relates to CI (don't re-add the CI-only steps)

This mirrors .ci-scripts/bsd/freebsd-provision.bash (the source of truth — keep this skill in sync if it changes). The local setup deliberately differs from CI, and each difference is safe:

• Skips CI host-bootstrap (free disk space, apt-get qemu, make /dev/kvm writable) — your host already has qemu and a usable hardware accelerator (Step 0 verified it).
• Persistent VM instead of built-fresh-and-killed per run.
• ssh adds -o UserKnownHostsFile=/dev/null -o LogLevel=ERROR to quiet the host-key warning: a persistent VM reused on localhost:2222 collides with the stale known_hosts entry from a prior VM. CI's ephemeral runners never reuse the port, so freebsd-provision.bash doesn't bother.
• -smp 8 for build speed (CI uses 4), and a -pidfile for the lifecycle commands.
• No GHCR libs cache (that's token-gated CI plumbing) — you just run cmake -P lib/build-libs.cmake once.

The DragonFly and OpenBSD CI VMs follow the same shape (.ci-scripts/bsd/{dragonfly,openbsd}-provision.bash) and each has its own skill: create-dragonfly-dev-env (gcc-only, and it drives a VGA console) and create-openbsd-dev-env (also cloud-init, but with static-PIE static-link checks, a raised datasize limit, and the source under a /build disk). This skill is FreeBSD-only; load a sibling if you need one of those.