Add linting, smoke harness, CI, and tests

.clang-format

@@ -0,0 +1,6 @@
+BasedOnStyle: LLVM
+IndentWidth: 4
+ColumnLimit: 100
+SortIncludes: false
+AllowShortIfStatementsOnASingleLine: Never
+BreakBeforeBraces: Attach

.dockerignore

@@ -0,0 +1,5 @@
+.git
+.DS_Store
+ld_preload
+ld_preload.so
+smoke-artifacts

.editorconfig

@@ -0,0 +1,17 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.go]
+indent_style = tab
+
+[*.{c,h}]
+indent_style = space
+indent_size = 4
+
+[*.md]
+trim_trailing_whitespace = false

.github/workflows/ci.yml

@@ -0,0 +1,81 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+concurrency:
+  group: ci-${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  lint-and-test:
+    name: Lint and Test
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v7
+
+      - name: Set up Go
+        uses: actions/setup-go@v6
+        with:
+          go-version: "1.26.0"
+          cache: true
+
+      - name: Install clang-format
+        run: sudo apt-get update && sudo apt-get install -y clang-format
+
+      - name: Install Go tools
+        run: make tools
+
+      - name: Verify formatting
+        run: make fmt-check
+
+      - name: Lint and unit test
+        run: make lint
+
+  macos-sanity:
+    name: macOS Sanity
+    runs-on: macos-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v7
+
+      - name: Set up Go
+        uses: actions/setup-go@v6
+        with:
+          go-version-file: go.mod
+          cache: true
+
+      - name: Build and test
+        run: |
+          go test ./...
+          make build
+
+  docker-smoke:
+    name: Docker Smoke
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v7
+
+      - name: Run Docker smoke harness
+        run: make docker-smoke
+
+      - name: Upload smoke artifacts
+        if: failure()
+        uses: actions/upload-artifact@v7
+        with:
+          name: smoke-artifacts-${{ github.run_id }}
+          path: smoke-artifacts/
+          if-no-files-found: ignore
+          retention-days: 7

.gitignore

@@ -1,26 +1,4 @@
-# If you prefer the allow list template instead of the deny list, see community template:
-# https://github.com/github/gitignore/blob/main/community/Golang/Go.AllowList.gitignore
-#
-# Binaries for programs and plugins
 ld_preload
-ld_preload.h
 ld_preload.so
-
-# Test binary, built with `go test -c`
-*.test
-
-# Output of the go coverage tool, specifically when used with LiteIDE
-*.out
-
-# Dependency directories (remove the comment below to include it)
-# vendor/
-
-# Go workspace file
-go.work
-go.work.sum
-
-# env file
-.env
-
-# IDE files
-.vscode/
+smoke/fixture
+smoke-artifacts/

.golangci.yml

@@ -0,0 +1,72 @@
+version: "2"
+
+run:
+  issues-exit-code: 1
+  tests: true
+
+output:
+  formats:
+    text:
+      path: stdout
+      print-linter-name: true
+      print-issued-lines: true
+
+linters:
+  enable:
+    - bidichk
+    - bodyclose
+    - errcheck
+    - errorlint
+    - gocheckcompilerdirectives
+    - gocritic
+    - gosec
+    - govet
+    - ineffassign
+    - misspell
+    - nakedret
+    - nilerr
+    - revive
+    - staticcheck
+    - unconvert
+    - unused
+    - wastedassign
+
+  settings:
+    errcheck:
+      check-type-assertions: false
+      check-blank: false
+    gocritic:
+      enabled-checks:
+        - deferInLoop
+      disabled-checks:
+        - ifElseChain
+        - elseif
+    nakedret:
+      max-func-lines: 30
+
+  exclusions:
+    generated: lax
+    rules:
+      - linters:
+          - revive
+        text: package-comments
+      - linters:
+          - revive
+        text: var-naming
+      - linters:
+          - revive
+        text: unused-parameter
+
+issues:
+  max-issues-per-linter: 0
+  max-same-issues: 0
+  new: false
+
+formatters:
+  enable:
+    - gofmt
+  settings:
+    gofmt:
+      simplify: true
+  exclusions:
+    generated: lax

Dockerfile.smoke

@@ -0,0 +1,16 @@
+ARG GO_BASE_IMAGE=golang:1.26-bookworm
+
+FROM ${GO_BASE_IMAGE}
+
+RUN apt-get update && \
+    apt-get install -y --no-install-recommends \
+        build-essential \
+        coreutils \
+        strace \
+        && rm -rf /var/lib/apt/lists/*
+
+WORKDIR /workspace
+
+COPY . .
+
+CMD ["./smoke/run.sh"]

lefthook.yml

@@ -0,0 +1,11 @@
+pre-commit:
+  commands:
+    fmt-check:
+      run: make fmt-check
+    lint:
+      run: make lint
+
+pre-push:
+  commands:
+    docker-smoke:
+      run: make docker-smoke

makefile

@@ -1,26 +1,121 @@
-# Define variables
 APP_NAME := ld_preload
 SRC := .
 SO_NAME := ld_preload.so
+GOFMT_FILES := $(shell find . -name '*.go' -not -path './vendor/*')
+C_FILES := $(shell find . \( -name '*.c' -o -name '*.h' \) -not -path './vendor/*')
+GOLANGCI_LINT_VERSION := v2.4.0
+STATICCHECK_VERSION := 2025.1.1
+LEFTHOOK_VERSION := v1.12.4
+GOBIN ?= $(or $(shell go env GOBIN),$(firstword $(subst :, ,$(shell go env GOPATH)))/bin)
+GOLANGCI_LINT := $(GOBIN)/golangci-lint
+STATICCHECK := $(GOBIN)/staticcheck
+LEFTHOOK := $(GOBIN)/lefthook
+SMOKE_IMAGE_BOOKWORM := golang:1.26-bookworm
+SMOKE_IMAGE_BULLSEYE := golang:1.24-bullseye
+SMOKE_TAG_BOOKWORM := ld_preload-smoke:bookworm
+SMOKE_TAG_BULLSEYE := ld_preload-smoke:bullseye
+
+.DEFAULT_GOAL := help
+
+.PHONY: help
+help:
+	@printf "Usage:\n"
+	@printf "  make %-12s %s\n" "build" "Build the executable and shared object"
+	@printf "  make %-12s %s\n" "fmt" "Format Go and C sources"
+	@printf "  make %-12s %s\n" "fmt-check" "Verify formatting without changing files"
+	@printf "  make %-12s %s\n" "lint" "Run Go linters and tests"
+	@printf "  make %-12s %s\n" "lint-fix" "Apply supported auto-fixes"
+	@printf "  make %-12s %s\n" "docker-smoke" "Run Linux LD_PRELOAD smoke tests in both Docker images"
+	@printf "  make %-12s %s\n" "docker-smoke-bookworm" "Run smoke tests in Debian bookworm"
+	@printf "  make %-12s %s\n" "docker-smoke-bullseye" "Run smoke tests in Debian bullseye"
+	@printf "  make %-12s %s\n" "hooks" "Install local git hooks with lefthook"
+	@printf "  make %-12s %s\n" "tools" "Install Go-based developer tools"
+	@printf "  make %-12s %s\n" "clean" "Remove build artifacts"
 
-# Default target
 .PHONY: all
 all: build
 
-# Build target: creates both an executable and a shared object
 .PHONY: build
 build:
-	# Build executable
 	go build -o $(APP_NAME) $(SRC)
-	# Build shared object
-	go build -o $(SO_NAME) -buildmode=c-shared $(SRC)
+	@if [ "$$(uname -s)" = "Linux" ]; then \
+		go build -o $(SO_NAME) -buildmode=c-shared $(SRC); \
+	else \
+		printf '%s\n' 'Skipping shared object build on non-Linux host.'; \
+	fi
 
-# Run target: implicitly calls build, then runs the application
 .PHONY: run
 run: build
 	./$(APP_NAME)
 
-# Clean target: removes the executable and shared object
+.PHONY: tools
+tools:
+	go install github.com/golangci/golangci-lint/v2/cmd/golangci-lint@$(GOLANGCI_LINT_VERSION)
+	go install honnef.co/go/tools/cmd/staticcheck@$(STATICCHECK_VERSION)
+	go install github.com/evilmartians/lefthook@$(LEFTHOOK_VERSION)
+
+.PHONY: hooks
+hooks:
+	$(LEFTHOOK) install
+
+.PHONY: fmt
+fmt:
+	gofmt -w $(GOFMT_FILES)
+	@if command -v clang-format >/dev/null 2>&1; then \
+		clang-format -i $(C_FILES); \
+	else \
+		printf '%s\n' 'clang-format not found; Go files formatted, C files skipped.'; \
+	fi
+
+.PHONY: fmt-check
+fmt-check:
+	@test -z "$$(gofmt -l $(GOFMT_FILES))" || \
+		(printf '%s\n' 'Go files need formatting:'; gofmt -l $(GOFMT_FILES); exit 1)
+	@if command -v clang-format >/dev/null 2>&1; then \
+		tmpdir=$$(mktemp -d); \
+		failed=0; \
+		for file in $(C_FILES); do \
+			out="$$tmpdir/$$(basename "$$file")"; \
+			clang-format "$$file" > "$$out"; \
+			if ! cmp -s "$$file" "$$out"; then \
+				printf '%s\n' "$$file"; \
+				failed=1; \
+			fi; \
+		done; \
+		rm -rf "$$tmpdir"; \
+		test $$failed -eq 0 || (printf '%s\n' 'C files need formatting.'; exit 1); \
+	else \
+		printf '%s\n' 'clang-format not found; skipping C format check.'; \
+	fi
+
+.PHONY: lint
+lint:
+	$(GOLANGCI_LINT) run
+	$(STATICCHECK) ./...
+	go test ./...
+
+.PHONY: lint-fix
+lint-fix:
+	$(GOLANGCI_LINT) run --fix
+	$(MAKE) fmt
+
+.PHONY: docker-smoke
+docker-smoke: docker-smoke-bookworm docker-smoke-bullseye
+
+.PHONY: docker-smoke-bookworm
+docker-smoke-bookworm:
+	chmod +x smoke/run.sh
+	docker build --build-arg GO_BASE_IMAGE=$(SMOKE_IMAGE_BOOKWORM) -f Dockerfile.smoke -t $(SMOKE_TAG_BOOKWORM) .
+	mkdir -p smoke-artifacts/bookworm
+	docker run --rm -e SMOKE_SUITE=bookworm -v "$(CURDIR)/smoke-artifacts:/workspace/smoke-artifacts" $(SMOKE_TAG_BOOKWORM)
+
+.PHONY: docker-smoke-bullseye
+docker-smoke-bullseye:
+	chmod +x smoke/run.sh
+	docker build --build-arg GO_BASE_IMAGE=$(SMOKE_IMAGE_BULLSEYE) -f Dockerfile.smoke -t $(SMOKE_TAG_BULLSEYE) .
+	mkdir -p smoke-artifacts/bullseye
+	docker run --rm -e SMOKE_SUITE=bullseye -v "$(CURDIR)/smoke-artifacts:/workspace/smoke-artifacts" $(SMOKE_TAG_BULLSEYE)
+
 .PHONY: clean
 clean:
-	rm -f $(APP_NAME) $(SO_NAME)
+	rm -f $(APP_NAME) $(SO_NAME) ld_preload.h