GNUmakefile

# Nuke built-in rules and variables.
# Auto-detect CPU cores for parallel compilation (override with: make JOBS=4)
JOBS ?= $(shell nproc 2>/dev/null || sysctl -n hw.ncpu 2>/dev/null || echo 4)
override MAKEFLAGS += -rR -j $(JOBS) 

override IMAGE_NAME := cottage

# set to true to use the nightly OVMF image
OVMF_USE_NIGHTLY := false

# Convenience macro to reliably declare user overridable variables.
define DEFAULT_VAR =
    ifeq ($(origin $1),default)
        override $(1) := $(2)
    endif
    ifeq ($(origin $1),undefined)
        override $(1) := $(2)
    endif
endef

OVMF_IMAGE := /usr/share/ovmf/OVMF.fd

ifeq ($(OVMF_USE_NIGHTLY),true)
	OVMF_IMAGE := ovmf/OVMF.fd
endif

# Toolchain for building the 'limine' executable for the host.
override DEFAULT_HOST_CC := cc
$(eval $(call DEFAULT_VAR,HOST_CC,$(DEFAULT_HOST_CC)))
override DEFAULT_HOST_CFLAGS := -g -O2 -pipe
$(eval $(call DEFAULT_VAR,HOST_CFLAGS,$(DEFAULT_HOST_CFLAGS)))
override DEFAULT_HOST_CPPFLAGS :=
$(eval $(call DEFAULT_VAR,HOST_CPPFLAGS,$(DEFAULT_HOST_CPPFLAGS)))
override DEFAULT_HOST_LDFLAGS :=
$(eval $(call DEFAULT_VAR,HOST_LDFLAGS,$(DEFAULT_HOST_LDFLAGS)))
override DEFAULT_HOST_LIBS :=
$(eval $(call DEFAULT_VAR,HOST_LIBS,$(DEFAULT_HOST_LIBS)))

.PHONY: all
all: $(IMAGE_NAME).iso

.PHONY: all-hdd
all-hdd: $(IMAGE_NAME).hdd

# alias test=run-uefi (cuts down on keystrokes)
.PHONY: test
test: run-uefi

# stress test target - builds with stress tests enabled and runs multiple iterations
# Usage: make stress-test ITERATIONS=10 TIMEOUT=30
.PHONY: stress-test
stress-test:
	./scripts/stress-test.sh $(ITERATIONS) $(TIMEOUT)

# parallel boot test for race condition debugging
# Usage: make test-parallel RUNS=50 CPUS=2 PARALLEL=6
# If PARALLEL not specified, auto-detects based on host CPUs / CPUS per VM
.PHONY: test-parallel
test-parallel: ovmf $(IMAGE_NAME).iso
ifdef PARALLEL
	./scripts/test-parallel.sh -n $(or $(RUNS),20) -c $(or $(CPUS),2) -j $(PARALLEL)
else
	./scripts/test-parallel.sh -n $(or $(RUNS),20) -c $(or $(CPUS),2)
endif

# headless test for CI/automated testing (no GUI window)
# Usage: make test-headless TIMEOUT=30  (runs for 30 seconds then exits)
# Without TIMEOUT, runs until crash or manual termination
.PHONY: test-headless
test-headless: ovmf $(IMAGE_NAME).iso
ifdef TIMEOUT
	timeout $(TIMEOUT) qemu-system-x86_64 $(QEMU_FLAGS) -display none -bios $(OVMF_IMAGE) -cdrom $(IMAGE_NAME).iso -boot d || true
else
	qemu-system-x86_64 $(QEMU_FLAGS) -display none -bios $(OVMF_IMAGE) -cdrom $(IMAGE_NAME).iso -boot d
endif

QEMU_FLAGS := -d cpu_reset -smp cpus=1 -M q35 -m 2G -serial stdio -action panic=none

# Networking: e1000e NIC (e1000e supports MSI)
# Use TAP=1 for host-to-guest connectivity (requires: sudo ./scripts/setup-tap.sh)
# Default is user-mode networking (guest can reach out, but host can't ping in)
ifdef TAP
QEMU_FLAGS += -netdev tap,id=net0,ifname=tap0,script=no,downscript=no -device e1000e,netdev=net0
else
QEMU_FLAGS += -netdev user,id=net0 -device e1000e,netdev=net0
endif

# Packet capture: use PCAP=1 to dump packets to packets.pcap
# Usage: make run-uefi PCAP=1
ifdef PCAP
QEMU_FLAGS += -object filter-dump,id=dump0,netdev=net0,file=packets.pcap
endif

# For stress testing, use multiple CPUs to maximize race condition detection
QEMU_STRESS_FLAGS := -d cpu_reset -smp cpus=4 -M q35 -m 2G -serial stdio -action panic=none

# uncomment to start gdbserver and freeze on launch
# QEMU_FLAGS += -S -s

.PHONY: run
run: $(IMAGE_NAME).iso
	qemu-system-x86_64 $(QEMU_FLAGS) -cdrom $(IMAGE_NAME).iso -boot d


.PHONY: run-uefi
run-uefi: ovmf $(IMAGE_NAME).iso
	qemu-system-x86_64 $(QEMU_FLAGS) -bios $(OVMF_IMAGE) -cdrom $(IMAGE_NAME).iso -boot d

.PHONY: run-hdd
run-hdd: $(IMAGE_NAME).hdd
	qemu-system-x86_64 $(QEMU_FLAGS) -hda $(IMAGE_NAME).hdd

.PHONY: run-hdd-uefi
run-hdd-uefi: ovmf $(IMAGE_NAME).hdd
	qemu-system-x86_64 $(QEMU_FLAGS) -bios ovmf/OVMF.fd -hda $(IMAGE_NAME).hdd

ovmf:
	mkdir -p ovmf
	cd ovmf && curl -Lo OVMF.fd https://retrage.github.io/edk2-nightly/bin/RELEASEX64_OVMF.fd

limine:
	git clone https://github.com/limine-bootloader/limine.git --branch=v5.x-branch-binary --depth=1
	$(MAKE) -C limine \
		CC="$(HOST_CC)" \
		CFLAGS="$(HOST_CFLAGS)" \
		CPPFLAGS="$(HOST_CPPFLAGS)" \
		LDFLAGS="$(HOST_LDFLAGS)" \
		LIBS="$(HOST_LIBS)"

ifdef COTTAGE_DEBUG
KERNEL_MAKEFLAGS := COTTAGE_DEBUG=1
else
KERNEL_MAKEFLAGS :=
endif

ifdef COTTAGE_STRESS_TEST
KERNEL_MAKEFLAGS += COTTAGE_STRESS_TEST=1
endif


.PHONY: kernel
kernel:
	$(MAKE) -C kernel $(KERNEL_MAKEFLAGS)

.PHONY: init
init:
	$(MAKE) -C init

$(IMAGE_NAME).iso: limine kernel init
	rm -rf iso_root
	mkdir -p iso_root
	cp -v kernel/bin/kernel init/bin/initramfs.tar \
		limine.cfg limine/limine-bios.sys limine/limine-bios-cd.bin limine/limine-uefi-cd.bin iso_root/
	mkdir -p iso_root/EFI/BOOT
	cp -v limine/BOOTX64.EFI iso_root/EFI/BOOT/
	cp -v limine/BOOTIA32.EFI iso_root/EFI/BOOT/
	xorriso -as mkisofs -b limine-bios-cd.bin \
		-no-emul-boot -boot-load-size 4 -boot-info-table \
		--efi-boot limine-uefi-cd.bin \
		-efi-boot-part --efi-boot-image --protective-msdos-label \
		iso_root -o $(IMAGE_NAME).iso
	./limine/limine bios-install $(IMAGE_NAME).iso
	rm -rf iso_root

$(IMAGE_NAME).hdd: limine kernel init
	rm -f $(IMAGE_NAME).hdd
	dd if=/dev/zero bs=1M count=0 seek=64 of=$(IMAGE_NAME).hdd
	sgdisk $(IMAGE_NAME).hdd -n 1:2048 -t 1:ef00
	./limine/limine bios-install $(IMAGE_NAME).hdd
	mformat -i $(IMAGE_NAME).hdd@@1M
	mmd -i $(IMAGE_NAME).hdd@@1M ::/EFI ::/EFI/BOOT
	mcopy -i $(IMAGE_NAME).hdd@@1M kernel/bin/kernel limine.cfg limine/limine-bios.sys ::/
	mcopy -i $(IMAGE_NAME).hdd@@1M limine/BOOTX64.EFI ::/EFI/BOOT
	mcopy -i $(IMAGE_NAME).hdd@@1M limine/BOOTIA32.EFI ::/EFI/BOOT

.PHONY: clean
clean:
	rm -rf iso_root $(IMAGE_NAME).iso $(IMAGE_NAME).hdd
	$(MAKE) -C kernel clean
	$(MAKE) -C init clean

.PHONY: distclean
distclean: clean
	rm -rf limine ovmf
	$(MAKE) -C kernel distclean