Add support for freebsd and various small fixes

.github/workflows/build-trigger.yml

@@ -32,6 +32,7 @@ jobs:
               - 'VERSION'
             dockerfile:
               - 'Dockerfile'
+              - 'Dockerfile.freebsd'
             c:
               - 'Makefile'
               - 'main.c'

.github/workflows/build.yml

@@ -93,8 +93,68 @@ jobs:
           -a "ref=${{github.sha}}" \
           -a "author=Nubificus LTD"
 
+  build-freebsd:
+    # Cross-compiled on a Linux amd64 runner (see Dockerfile.freebsd); the
+    # resulting image is stamped os=freebsd and amended into the manifest list
+    # below. Required: a FreeBSD build failure blocks the pipeline.
+    runs-on: ${{ format('{0}-{1}', join(fromJSON(inputs.runner), '-'), 'amd64') }}
+    permissions:
+      id-token: write # to complete the identity challenge with sigstore/fulcio when running outside of PRs
+    env:
+      IMAGE_NAME: ${{ inputs.registry }}/${{ github.repository }}
+    steps:
+      - name: Checkout the repo
+        uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+
+      - name: Set short SHA
+        run: echo "SHA_SHORT=${GITHUB_SHA::7}" >> $GITHUB_ENV
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@8d2750c68a42422c14e847fe6c8ac0403b4cbd6f # v3.12.0
+
+      - name: Log into registry ${{ inputs.registry }}
+        uses: docker/login-action@5e57cd118135c172c3672efd75eb46360885c0ef
+        with:
+          registry: ${{ inputs.registry }}
+          username: ${{ secrets.harbor_user }}
+          password: ${{ secrets.harbor_secret }}
+
+      - name: Extract Docker metadata
+        id: meta
+        uses: docker/metadata-action@318604b99e75e41977312d83839a89be02ca4893
+        with:
+          images: ${{ env.IMAGE_NAME }}
+          tags: |
+            type=sha,prefix=freebsd-amd64-
+
+      - name: Build and push urunit FreeBSD image
+        id: build-and-push
+        uses: docker/build-push-action@9e436ba9f2d7bcd1d038c8e55d039d37896ddc5d # master
+        with:
+          context: .
+          file: "Dockerfile.freebsd"
+          platforms: freebsd/amd64
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          push: true
+          provenance: false
+
+      - name: Install cosign
+        uses: sigstore/cosign-installer@d58896d6a1865668819e1d91763c7751a165e159 # main
+
+      - name: Sign the published Docker image
+        env:
+          COSIGN_EXPERIMENTAL: "true"
+          DIGEST: ${{steps.build-and-push.outputs.digest}}
+        run: |
+          cosign sign --yes ${{ env.IMAGE_NAME }}@$DIGEST \
+          -a "repo=${{github.repository}}" \
+          -a "workflow=${{github.workflow}}" \
+          -a "ref=${{github.sha}}" \
+          -a "author=Nubificus LTD"
+
   manifest:
-    needs: [build-all]
+    needs: [build-all, build-freebsd]
     runs-on: base-dind-2204-amd64
     permissions:
       id-token: write # to complete the identity challenge with sigstore/fulcio when running outside of PRs
@@ -140,6 +200,10 @@ jobs:
             amend_command+=" --amend ${{ env.IMAGE_NAME }}:$arch-${{ env.SHA_SHORT }}"
           done
 
+          # Include the FreeBSD image (build-freebsd is a required dependency,
+          # so if we got here it was built and pushed).
+          amend_command+=" --amend ${{ env.IMAGE_NAME }}:freebsd-amd64-${{ env.SHA_SHORT }}"
+
           echo "-------------------- Amend command constructed -------------------"
           echo "$amend_command"
 

Dockerfile.freebsd

@@ -0,0 +1,38 @@
+# Builds the FreeBSD static urunit and packages it into a scratch image.
+#
+# The build runs on a Linux builder and cross-compiles for FreeBSD with clang +
+# lld against a sysroot extracted from the FreeBSD base distribution. The final
+# scratch stage only copies the binary, so nothing FreeBSD is ever executed at
+# build time. Stamp the image OS with buildx, e.g.:
+#
+#   docker buildx build --platform freebsd/amd64 -f Dockerfile.freebsd .
+#
+# which sets os=freebsd in the resulting image config.
+
+FROM --platform=$BUILDPLATFORM alpine AS builder
+
+ARG FREEBSD_VERSION=14.3-RELEASE
+ARG TARGET_TRIPLE=x86_64-unknown-freebsd14.3
+
+WORKDIR /urunit
+
+RUN apk add --no-cache clang lld make curl tar xz
+
+# FreeBSD sysroot: headers plus the (static) libraries and startup objects from
+# the base distribution. Only the parts a sysroot needs are extracted.
+RUN mkdir -p /sysroot && \
+    curl -fsSL "https://download.freebsd.org/releases/amd64/amd64/${FREEBSD_VERSION}/base.txz" \
+      | tar -xJf - -C /sysroot ./lib ./usr/lib ./usr/include
+
+COPY Makefile .
+COPY src src
+
+# TARGET_OS must be explicit: the Makefile would otherwise infer the OS from the
+# Linux builder's uname. Everything the cross toolchain needs rides on CC.
+RUN make TARGET_OS=FreeBSD \
+      CC="clang --target=${TARGET_TRIPLE} --sysroot=/sysroot -fuse-ld=lld" \
+      static
+
+FROM scratch
+COPY --from=builder /urunit/dist/urunit_static /urunit
+ENTRYPOINT ["/urunit"]

Makefile

@@ -77,6 +77,9 @@ endif
 ifeq ($(TARGET_OS),Linux)
     URUNIT_SRC += ${SOURCE_DIR}/linux.c
 endif
+ifeq ($(TARGET_OS),FreeBSD)
+    URUNIT_SRC += ${SOURCE_DIR}/freebsd.c
+endif
 
 # Main Building rules
 #

README.md

@@ -70,8 +70,12 @@ following information:
 
 - The list of the environment variables to set for the application
 - The configuration for the process execution environment.
+- The application command to execute, when `urunit` is started without a
+  command line (optional).
 - The list of mounts of block devices. Each block device is defined by its
   serial id and it will get mounted in the defined mountpoint.
+- The network configuration (IP address, gateway and netmask) for guests
+  that can not get it from the kernel command line (optional).
 
 The file can be specified to `urunit` setting the `URUNIT_CONFIG`
 environment variable with the path to the configuration file.
@@ -86,14 +90,32 @@ UCS
 UID: <uid_for_the_application>
 GID: <gid_for_the_application>
 WD:  <working_directory>
+ARC: <number_of_application_arguments>
+ARV: <application_argument>
+...
 UCE
 UBS
 ID: <serial_id>
 MP: <mountpoint>
 ...
 UBE
+UNS
+IP:  <ipv4_address>
+GW:  <gateway>
+MSK: <netmask>
+UNE
 ```
 
+Inside the `UCS` section, the application command is optional: `ARC` holds the
+number of arguments and is followed by exactly that many `ARV` lines, one per
+argument, each taken verbatim. It is used when `urunit` is started without a
+command line, in which case the command from the configuration is executed.
+
+The `UNS` section is optional and provides the network configuration for
+guests that can not get it from the kernel command line: `IP` is the IPv4
+address, `GW` the gateway and `MSK` the netmask. An empty value (e.g. `IP:`)
+leaves the field unset.
+
 ## Installation
 
 Using one of the following methods, we can install `urunit` either in a

src/common.h

@@ -33,14 +33,20 @@
 #define DEBUG_PRINTF(fmt, ...) \
 	do { if (SHOW_DEBUG) fprintf(stderr, "[DEBUG] " fmt, __VA_ARGS__); } while (0)
 
-#define DEBUG_PRINT(fmt, ...) \
+#define DEBUG_PRINT(fmt) \
 	do { if (SHOW_DEBUG) fprintf(stderr, "[DEBUG] " fmt); } while (0)
 
 struct block_config {
 	char *id;
 	char *mountpoint;
 };
 
+struct net_config {
+	char *ip;
+	char *gateway;
+	char *mask;
+};
+
 int ensure_dir(const char *path);
 int mkdir_all(const char *path, mode_t mode, char *first_dir);
 int rm_empty_dirs(const char *dir, const char *top_dir);
@@ -49,14 +55,20 @@ int is_block_fs(const char *fs_type);
 int is_network_fs(const char *fs_type);
 int is_cloud_storage_fs(const char *fs_type);
 
+// Platform specific functions
+int setup_console(void);
+int remount_root_rw(void);
+char *get_boot_var(const char *name);
+char *read_raw_device(int fd, size_t *size);
+int configure_network(struct net_config *net);
 int read_block_dev_serial(const char *device_name, char *serial, const size_t size);
 int find_vblock_device_by_order(const uint32_t n, char *device_path);
 int find_vblock_device_by_serial(const char *target_serial, char *device_path);
-int mount_special_fs();
+int mount_special_fs(void);
 int mount_block_vols(struct block_config **vols);
-int set_default_route();
-void unmount_external();
-int set_subreaper();
-void request_reboot();
+int set_default_route(void);
+void unmount_external(void);
+int set_subreaper(void);
+void request_reboot(void);
 
 #endif // COMMON_H