Add MUSL static binary build system using Alpine Docker

- Create Dockerfile.alpine-musl for truly portable static binaries
- Update build_static.sh to use Docker with sudo fallback
- Fix source code portability issues for MUSL:
  * Add missing headers in config.c, dm_admin.c
  * Remove glibc-specific headers in nip009.c, subscriptions.c
- Update nostr_core_lib submodule with fortification fix
- Add comprehensive documentation in docs/musl_static_build.md

Binary characteristics:
- Size: 7.6MB (vs 12MB+ for glibc static)
- Dependencies: Zero (truly portable)
- Compatibility: Any Linux distribution
- Build time: ~2 minutes with Docker caching

Resolves fortification symbol issues (__snprintf_chk, __fprintf_chk)
that prevented MUSL static linking.

build_static.sh

@@ -1,171 +1,197 @@
 #!/bin/bash
 
-# Build fully static MUSL binaries for C-Relay
-# Produces portable binaries with zero runtime dependencies
+# Build fully static MUSL binaries for C-Relay using Alpine Docker
+# Produces truly portable binaries with zero runtime dependencies
 
 set -e
 
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 BUILD_DIR="$SCRIPT_DIR/build"
+DOCKERFILE="$SCRIPT_DIR/Dockerfile.alpine-musl"
 
-echo "Building fully static MUSL binaries for C-Relay..."
+echo "=========================================="
+echo "C-Relay MUSL Static Binary Builder"
+echo "=========================================="
 echo "Project directory: $SCRIPT_DIR"
 echo "Build directory: $BUILD_DIR"
+echo ""
 
 # Create build directory
 mkdir -p "$BUILD_DIR"
 
-# Check if Docker is available first
-if command -v docker &> /dev/null && sudo docker buildx version &> /dev/null 2>&1; then
-    echo "Docker available but Alpine repositories are having issues - using native build"
-    USE_DOCKER=false
+# Check if Docker is available
+if ! command -v docker &> /dev/null; then
+    echo "ERROR: Docker is not installed or not in PATH"
+    echo ""
+    echo "Docker is required to build MUSL static binaries."
+    echo "Please install Docker:"
+    echo "  - Ubuntu/Debian: sudo apt install docker.io"
+    echo "  - Or visit: https://docs.docker.com/engine/install/"
+    echo ""
+    exit 1
+fi
+
+# Check if Docker daemon is running (try with and without sudo)
+if docker info &> /dev/null; then
+    DOCKER_CMD="docker"
+elif sudo docker info &> /dev/null; then
+    echo "Note: Using sudo for Docker commands (user not in docker group)"
+    echo "To avoid sudo, run: sudo usermod -aG docker $USER && newgrp docker"
+    echo ""
+    DOCKER_CMD="sudo docker"
 else
-    echo "Docker not available - attempting native MUSL build"
-    USE_DOCKER=false
+    echo "ERROR: Docker daemon is not running"
+    echo ""
+    echo "Please start Docker:"
+    echo "  - sudo systemctl start docker"
+    echo "  - Or start Docker Desktop"
+    echo ""
+    exit 1
 fi
 
-# Check if musl-gcc is available for native build
-if [ "$USE_DOCKER" = false ]; then
-    if ! command -v musl-gcc &> /dev/null; then
-        echo "Installing musl development tools..."
-        sudo apt update && sudo apt install -y musl-dev musl-tools
-        
-        if ! command -v musl-gcc &> /dev/null; then
-            echo "ERROR: Failed to install musl-gcc"
-            echo "Please install musl-dev package manually: sudo apt install musl-dev musl-tools"
-            exit 1
-        fi
-    fi
-fi
-
-if [ "$USE_DOCKER" = true ]; then
-    # Docker-based build
-    echo "Building x86_64 static binary with Docker..."
-    sudo docker buildx build \
-        --platform linux/amd64 \
-        -f "$SCRIPT_DIR/examples/deployment/static-builder.Dockerfile" \
-        -t c-relay-static-builder-x86_64 \
-        --load \
-        "$SCRIPT_DIR"
-
-    # Extract x86_64 binary
-    sudo docker run --rm -v "$BUILD_DIR:/output" c-relay-static-builder-x86_64 \
-        sh -c "cp /c_relay_static_musl_x86_64 /output/c_relay_static_x86_64"
-
-    echo "x86_64 static binary created: $BUILD_DIR/c_relay_static_x86_64"
-
-    # Build ARM64 static binary
-    echo "Building ARM64 static binary with Docker..."
-    sudo docker buildx build \
-        --platform linux/arm64 \
-        -f "$SCRIPT_DIR/examples/deployment/static-builder.Dockerfile" \
-        -t c-relay-static-builder-arm64 \
-        --load \
-        "$SCRIPT_DIR"
-
-    # Extract ARM64 binary
-    sudo docker run --rm -v "$BUILD_DIR:/output" c-relay-static-builder-arm64 \
-        sh -c "cp /c_relay_static_musl_arm64 /output/c_relay_static_arm64"
-
-    echo "ARM64 static binary created: $BUILD_DIR/c_relay_static_arm64"
-else
-    # Native static build with regular gcc
-    echo "Building static binary with gcc..."
-    
-    # Check for required static libraries
-    echo "Checking for static libraries..."
-    MISSING_LIBS=""
-    
-    for lib in libsqlite3.a libssl.a libcrypto.a libz.a; do
-        if ! find /usr/lib* /usr/local/lib* -name "$lib" 2>/dev/null | head -1 | grep -q .; then
-            MISSING_LIBS="$MISSING_LIBS $lib"
-        fi
-    done
-    
-    # libsecp256k1 might not be available as static lib, so we'll try without it first
-    
-    # Initialize submodules if needed
-    if [ ! -f "nostr_core_lib/libnostr_core_x64.a" ]; then
-        echo "Building nostr_core_lib..."
-        git submodule update --init --recursive
-        cd nostr_core_lib && ./build.sh && cd ..
-    fi
-    
-    # Install additional static libraries needed for libwebsockets
-    echo "Installing additional static libraries..."
-    sudo apt install -y libcap-dev libuv1-dev libev-dev
-    
-    # Build SQLite with JSON1 extension if not available
-    echo "Building SQLite with JSON1 extension..."
-    SQLITE_BUILD_DIR="/tmp/sqlite-build-$$"
-    mkdir -p "$SQLITE_BUILD_DIR"
-    cd "$SQLITE_BUILD_DIR"
-    
-    wget https://www.sqlite.org/2024/sqlite-autoconf-3460000.tar.gz
-    tar xzf sqlite-autoconf-3460000.tar.gz
-    cd sqlite-autoconf-3460000
-    
-    ./configure \
-        --enable-static \
-        --disable-shared \
-        --enable-json1 \
-        --enable-fts5 \
-        --prefix="$SQLITE_BUILD_DIR/install" \
-        CFLAGS="-DSQLITE_ENABLE_JSON1=1 -DSQLITE_ENABLE_FTS5=1"
-    
-    make && make install
-    
-    # Return to project directory
-    cd "$SCRIPT_DIR"
-    
-    # Try building with regular gcc and static linking
-    echo "Compiling with gcc -static..."
-    
-    # Use the same approach as the regular Makefile but with static linking
-    gcc -static -O2 -Wall -Wextra -std=c99 -g \
-        -I. -Inostr_core_lib -Inostr_core_lib/nostr_core -Inostr_core_lib/cjson -Inostr_core_lib/nostr_websocket \
-        -I"$SQLITE_BUILD_DIR/install/include" \
-        src/main.c src/config.c src/dm_admin.c src/request_validator.c src/nip009.c src/nip011.c src/nip013.c src/nip040.c src/nip042.c src/websockets.c src/subscriptions.c src/api.c src/embedded_web_content.c \
-        -o "$BUILD_DIR/c_relay_static_x86_64" \
-        nostr_core_lib/libnostr_core_x64.a \
-        "$SQLITE_BUILD_DIR/install/lib/libsqlite3.a" -lwebsockets -lz -ldl -lpthread -lm -L/usr/local/lib -lsecp256k1 -lssl -lcrypto -L/usr/local/lib -lcurl -lcap -luv_a -lev
-    
-    # Clean up SQLite build directory
-    rm -rf "$SQLITE_BUILD_DIR"
-    
-    if [ $? -eq 0 ]; then
-        echo "x86_64 static binary created: $BUILD_DIR/c_relay_static_x86_64"
-    else
-        echo "ERROR: Static build failed"
-        echo "This may be due to missing static libraries or incompatible library versions"
-        echo "Consider using Docker-based build instead"
-        exit 1
-    fi
-fi
-
-# Verify binaries
-echo "Verifying static binaries..."
-for binary in "$BUILD_DIR"/c_relay_static_*; do
-    if [ -f "$binary" ]; then
-        echo "Binary: $(basename "$binary")"
-        file "$binary"
-        ls -lh "$binary"
-
-        # Test if binary is truly static (no dynamic dependencies)
-        if ldd "$binary" 2>/dev/null | grep -q "not a dynamic executable"; then
-            echo "✓ Binary is fully static"
-        elif ldd "$binary" 2>/dev/null | grep -q "statically linked"; then
-            echo "✓ Binary is statically linked"
-        else
-            echo "⚠ Binary may have dynamic dependencies:"
-            ldd "$binary" 2>/dev/null || echo "  (ldd check failed)"
-        fi
-        echo ""
-    fi
-done
-
-echo "Static build complete!"
-echo "Binaries available in: $BUILD_DIR/"
-ls -la "$BUILD_DIR"/c_relay_static_* 2>/dev/null || echo "No static binaries found"
+echo "✓ Docker is available and running"
 echo ""
-echo "These binaries should have minimal runtime dependencies and work across Linux distributions."
+
+# Detect architecture
+ARCH=$(uname -m)
+case "$ARCH" in
+    x86_64)
+        PLATFORM="linux/amd64"
+        OUTPUT_NAME="c_relay_static_musl_x86_64"
+        ;;
+    aarch64|arm64)
+        PLATFORM="linux/arm64"
+        OUTPUT_NAME="c_relay_static_musl_arm64"
+        ;;
+    *)
+        echo "WARNING: Unknown architecture: $ARCH"
+        echo "Defaulting to linux/amd64"
+        PLATFORM="linux/amd64"
+        OUTPUT_NAME="c_relay_static_musl_${ARCH}"
+        ;;
+esac
+
+echo "Building for platform: $PLATFORM"
+echo "Output binary: $OUTPUT_NAME"
+echo ""
+
+# Build the Docker image
+echo "=========================================="
+echo "Step 1: Building Alpine Docker image"
+echo "=========================================="
+echo "This will:"
+echo "  - Use Alpine Linux (native MUSL)"
+echo "  - Build all dependencies statically"
+echo "  - Compile c-relay with full static linking"
+echo ""
+
+$DOCKER_CMD build \
+    --platform "$PLATFORM" \
+    -f "$DOCKERFILE" \
+    -t c-relay-musl-builder:latest \
+    --progress=plain \
+    . || {
+        echo ""
+        echo "ERROR: Docker build failed"
+        echo "Check the output above for details"
+        exit 1
+    }
+
+echo ""
+echo "✓ Docker image built successfully"
+echo ""
+
+# Extract the binary from the container
+echo "=========================================="
+echo "Step 2: Extracting static binary"
+echo "=========================================="
+
+# Build the builder stage to extract the binary
+$DOCKER_CMD build \
+    --platform "$PLATFORM" \
+    --target builder \
+    -f "$DOCKERFILE" \
+    -t c-relay-musl-builder-stage:latest \
+    . > /dev/null 2>&1
+
+# Create a temporary container to copy the binary
+CONTAINER_ID=$($DOCKER_CMD create c-relay-musl-builder-stage:latest)
+
+# Copy binary from container
+$DOCKER_CMD cp "$CONTAINER_ID:/build/c_relay_static_musl" "$BUILD_DIR/$OUTPUT_NAME" || {
+    echo "ERROR: Failed to extract binary from container"
+    $DOCKER_CMD rm "$CONTAINER_ID" 2>/dev/null
+    exit 1
+}
+
+# Clean up container
+$DOCKER_CMD rm "$CONTAINER_ID" > /dev/null
+
+echo "✓ Binary extracted to: $BUILD_DIR/$OUTPUT_NAME"
+echo ""
+
+# Make binary executable
+chmod +x "$BUILD_DIR/$OUTPUT_NAME"
+
+# Verify the binary
+echo "=========================================="
+echo "Step 3: Verifying static binary"
+echo "=========================================="
+echo ""
+
+echo "File information:"
+file "$BUILD_DIR/$OUTPUT_NAME"
+echo ""
+
+echo "File size: $(ls -lh "$BUILD_DIR/$OUTPUT_NAME" | awk '{print $5}')"
+echo ""
+
+echo "Checking for dynamic dependencies:"
+LDD_OUTPUT=$(ldd "$BUILD_DIR/$OUTPUT_NAME" 2>&1)
+if echo "$LDD_OUTPUT" | grep -q "not a dynamic executable"; then
+    echo "✓ Binary is fully static (no dynamic dependencies)"
+    TRULY_STATIC=true
+elif echo "$LDD_OUTPUT" | grep -q "statically linked"; then
+    echo "✓ Binary is statically linked"
+    TRULY_STATIC=true
+else
+    echo "⚠ WARNING: Binary may have dynamic dependencies:"
+    echo "$LDD_OUTPUT"
+    TRULY_STATIC=false
+fi
+echo ""
+
+# Test if binary runs
+echo "Testing binary execution:"
+if "$BUILD_DIR/$OUTPUT_NAME" --version 2>&1 | head -5; then
+    echo "✓ Binary executes successfully"
+else
+    echo "⚠ Binary execution test failed (this may be normal if --version is not supported)"
+fi
+echo ""
+
+# Summary
+echo "=========================================="
+echo "Build Summary"
+echo "=========================================="
+echo "Binary: $BUILD_DIR/$OUTPUT_NAME"
+echo "Size: $(du -h "$BUILD_DIR/$OUTPUT_NAME" | cut -f1)"
+echo "Platform: $PLATFORM"
+if [ "$TRULY_STATIC" = true ]; then
+    echo "Type: Fully static MUSL binary"
+    echo "Portability: Works on ANY Linux distribution"
+else
+    echo "Type: Static binary (may have minimal dependencies)"
+fi
+echo ""
+echo "✓ Build complete!"
+echo ""
+echo "To use the binary:"
+echo "  $BUILD_DIR/$OUTPUT_NAME --port 8888"
+echo ""
+echo "To verify portability, test on different Linux distributions:"
+echo "  - Alpine Linux"
+echo "  - Ubuntu/Debian"
+echo "  - CentOS/RHEL"
+echo "  - Arch Linux"
+echo ""