Various fixes and improvements

.clang-format

@@ -0,0 +1,4 @@
+SortIncludes: false
+BasedOnStyle: Microsoft
+ColumnLimit: 0
+IndentWidth: 4

.github/workflows/CI.yml

@@ -0,0 +1,81 @@
+name: CI
+
+on:
+  push:
+    branches: [ master ]
+  workflow_dispatch:
+
+permissions: {}
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  build:
+    name: Build on ${{ matrix.os }}
+    permissions:
+      contents: read
+    strategy:
+      matrix:
+        os: [ubuntu-20.04, ubuntu-22.04, ubuntu-24.04, macos-13, macos-14, macos-15]
+    runs-on: ${{ matrix.os }}
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@main
+        with:
+          ref: master
+          fetch-depth: 0
+
+      - name: Compile and Test
+        run: |
+          if [[ "${{ matrix.os }}" == ubuntu-* ]]; then
+            export LDFLAGS="$LDFLAGS -static"
+          fi
+          make
+          sudo ./tests/process_iterator_test
+          random_file="$(mktemp $(printf 'X%.0s' $(seq 1 255)))"
+          cp ./tests/process_iterator_test ./tests/${random_file}
+          echo "./tests/${random_file}"
+          sudo ./tests/${random_file}
+
+      - name: Upload Artifacts
+        uses: actions/upload-artifact@main
+        with:
+          name: cpulimit-${{ matrix.os }}
+          path: src/cpulimit
+
+  build-FreeBSD:
+    name: Build on FreeBSD-${{ matrix.osver }}
+    permissions:
+      contents: read
+    strategy:
+      matrix:
+        osver: ['13.4', '14.1', '15.0']
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@main
+
+      - name: Build on FreeBSD
+        uses: vmactions/freebsd-vm@v1
+        with:
+          release: ${{ matrix.osver }}
+          usesh: true
+          prepare: |
+            pkg install -y lang/gcc gmake sudo
+          run: |
+            gmake
+            sudo ./tests/process_iterator_test
+            random_file="$(mktemp $(printf 'X%.0s' $(seq 1 255)))"
+            cp ./tests/process_iterator_test ./tests/${random_file}
+            echo "./tests/${random_file}"
+            sudo ./tests/${random_file}
+
+      - name: Upload Artifacts
+        uses: actions/upload-artifact@main
+        with:
+          name: cpulimit-FreeBSD-${{ matrix.osver }}
+          path: src/cpulimit

Makefile

@@ -1,5 +1,5 @@
 default: all
 
 .DEFAULT:
-	cd src && $(MAKE) $@
-	cd tests && $(MAKE) $@
+	$(MAKE) -C src $@
+	$(MAKE) -C tests $@

src/.gitignore

@@ -0,0 +1,3 @@
+*.o
+*~
+cpulimit

src/Makefile

@@ -1,28 +1,49 @@
-CC?=gcc
-CFLAGS?=-Wall -g -D_GNU_SOURCE
-TARGETS=cpulimit
-LIBS=list.o process_iterator.o process_group.o
-
-UNAME := $(shell uname)
-
+# Compiler configuration
+CC ?= gcc
+
+# Compiler flags
+override CFLAGS := $(filter-out -std=% -ansi -W%, $(CFLAGS)) \
+                   -std=c89 \
+                   -Wall \
+                   -Wextra \
+                   -pedantic \
+                   -Wold-style-definition \
+                   -Wmissing-prototypes \
+                   -Wstrict-prototypes \
+                   -Werror
+
+# Target binary
+TARGET := cpulimit
+
+# Detect operating system
+UNAME ?= $(shell uname)
+
+# Platform-specific linker flags
 ifeq ($(UNAME), FreeBSD)
-LIBS+=-lkvm
+    override LDFLAGS += -lkvm
 endif
 
-all::	$(TARGETS) $(LIBS)
+ifeq ($(UNAME), Darwin)
+    override LDFLAGS += -lproc
+endif
 
-cpulimit:	cpulimit.c $(LIBS)
-	$(CC) -o cpulimit cpulimit.c $(LIBS) $(CFLAGS)
+# Check for librt availability
+override LDFLAGS += $(shell \
+    echo "int main(void){ return 0; }" | \
+    $(CC) -x c -o /dev/null -lrt - 2>/dev/null && \
+    echo -lrt \
+)
 
-process_iterator.o: process_iterator.c process_iterator.h
-	$(CC) -c process_iterator.c $(CFLAGS)
+# Phony targets
+.PHONY: all clean
 
-list.o: list.c list.h
-	$(CC) -c list.c $(CFLAGS)
+# Default target
+all: $(TARGET)
 
-process_group.o: process_group.c process_group.h process_iterator.o list.o
-	$(CC) -c process_group.c $(CFLAGS)
+# Build target
+$(TARGET): $(wildcard *.c *.h)
+	$(CC) $(CFLAGS) $(filter-out process_iterator_%.c %.h, $^) $(LDFLAGS) -o $@
 
+# Clean target
 clean:
-	rm -f *~ *.o $(TARGETS)
-
+	rm -f *~ $(TARGET)