# Makefile for cbd

TOP := $(shell pwd)

# Tunables
VERSION := 1.0
WITH_DEBUG ?= true

# Default rule
.PHONY: all
all: all-targets

# Turn off default suffix rules
.SUFFIXES:

# Turn off RCS/SCCS rules
%: RCS/%,v
%: RCS/%
%: %,v
%: s.%
%: SCCS/s.%

# Always delete target when a rule fails
.DELETE_ON_ERROR:

# Kernel stuff
KVER ?= $(shell uname -r)
KDIR ?= /lib/modules/$(KVER)/build

# Build tools
CPP   := $(CROSS_COMPILE)cpp
CC    := $(CROSS_COMPILE)gcc
AR    := $(CROSS_COMPILE)ar
LD    := $(CROSS_COMPILE)gcc
STRIP := $(CROSS_COMPILE)strip

# Paths
OUT := out
OUT_OBJ := $(OUT)/obj
OUT_LIB := $(OUT)/lib
OUT_BIN := $(OUT)/bin
OUT_KMOD := $(OUT)/kmod

# Install locations
PREFIX ?= /usr/local
BINDIR ?= $(PREFIX)/bin
LIBDIR ?= $(PREFIX)/lib
MANDIR ?= $(PREFIX)/share/man
KMODDIR ?= /lib/modules/$(KVER)/misc

# Platform extensions
OBJ_EXT := .o
LIB_EXT := .a
SHLIB_EXT := .so
EXE_EXT :=
KMOD_EXT := .ko

# Build flags
ifeq ($(WITH_DEBUG),true)
DEBUG_CFLAGS := -g
DEBUG_LDFLAGS := -g
else
DEBUG_CFLAGS := -DNDEBUG
DEBUG_LDFLAGS :=
endif

CPPFLAGS :=
CFLAGS := $(DEBUG_CFLAGS) -Wall -Werror -Iinclude
LDFLAGS := $(DEBUG_LDFLAGS)

# Targets
LIB_NAME := libcbd
BIN_NAME := cbd
KMOD_NAME := dm-compress

# Sources
LIB_SRCS := \
	check.c \
	close.c \
	format.c \
	open.c \
	resize.c \
	stats.c \
	info.c \
	tune.c \
	util.c
BIN_SRCS := \
	cbd.c
KMOD_SRCS := \
	util.c \
	pbat.c \
	lbatpblk.c \
	lbatview.c \
	lbd.c \
	compress.c
KMOD_HDRS := \
	dm-compress.h

# Intermediates
LIB_OBJDIR := $(OUT_OBJ)/$(LIB_NAME)
LIB_OBJS := $(addprefix $(LIB_OBJDIR)/,$(LIB_SRCS:.c=$(OBJ_EXT)))
BIN_OBJDIR := $(OUT_OBJ)/$(BIN_NAME)
BIN_OBJS := $(addprefix $(BIN_OBJDIR)/,$(BIN_SRCS:.c=$(OBJ_EXT)))
EXE_LIBS := -ldevmapper -llz4 -lz
KMOD_OBJDIR := $(OUT_OBJ)/$(KMOD_NAME)

# Transforms
define copy-file
  @mkdir -p $(@D)
  cp $< $@
endef
define compile-c
  @mkdir -p $(@D)
  $(CC) $(CPPFLAGS) $(CFLAGS) -MD -MP -MF $(@D)/.$(@F:$(OBJ_EXT)=.d) -c -o $@ $<
endef
define make-static-lib
  @mkdir -p $(@D)
  @rm -f $@
  $(AR) r $@ $^
endef
define make-shared-lib
  @mkdir -p $(@D)
  $(LD) -shared -o $@ $^
endef
define link-executable
  @mkdir -p $(@D)
  $(LD) $(LDFLAGS) -o $@ $^ $(EXE_LIBS)
endef

# Version
ifeq (,$(wildcard .git))
  GIT_REV := none
else
  GIT_REV := $(shell git rev-parse --short HEAD)
  ifeq (,$(shell git diff-index --name-only HEAD))
    GIT_REV := $(GIT_REV)-clean
  else
    GIT_REV := $(GIT_REV)-dirty
  endif
endif
VERSION := $(VERSION)-$(GIT_REV)

version.h:
	@echo "/* Autogenerated file.  Do not edit. */" > .$@.tmp && \
	echo "#ifndef VERSION_H" >> .$@.tmp && \
	echo "#define VERSION_H" >> .$@.tmp && \
	echo "#endif" >> .$@.tmp && \
	rm -f $@ && \
	mv -f .$@.tmp $@

# Rules
$(LIB_OBJS): $(LIB_OBJDIR)/%.o: $(LIB_NAME)/%.c
	$(compile-c)

$(OUT_LIB)/$(LIB_NAME)$(LIB_EXT): $(LIB_OBJS)
	$(make-static-lib)

$(BIN_OBJS): $(BIN_OBJDIR)/%.o: $(BIN_NAME)/%.c
	$(compile-c)

$(OUT_BIN)/$(BIN_NAME)$(EXE_EXT): $(BIN_OBJS) $(OUT_LIB)/$(LIB_NAME)$(LIB_EXT)
	$(link-executable)

$(KMOD_NAME)/$(KMOD_NAME)$(KMOD_EXT): \
    $(addprefix $(KMOD_NAME)/,$(KMOD_SRCS)) \
    $(addprefix include/linux/,$(KMOD_HDRS))
	$(MAKE) -C $(KDIR) M=$(TOP)/$(KMOD_NAME) modules

$(OUT_KMOD)/$(KMOD_NAME)$(KMOD_EXT): $(KMOD_NAME)/$(KMOD_NAME)$(KMOD_EXT)
	$(copy-file)

.PHONY: all-targets
all-targets: \
	$(OUT_LIB)/$(LIB_NAME)$(LIB_EXT) \
	$(OUT_BIN)/$(BIN_NAME)$(EXE_EXT) \
	$(OUT_KMOD)/$(KMOD_NAME)$(KMOD_EXT)

.PHONY: install
install: all-targets
	mkdir -p $(BINDIR)
	cp -f $(OUT_BIN)/$(BIN_NAME)$(EXE_EXT) $(BINDIR)
	$(MAKE) -C $(KDIR) M=$(TOP)/$(KMOD_NAME) modules_install 2>/dev/null
	depmod -a

.PHONY: clean
clean:
	rm -rf $(OUT)
	$(MAKE) -C $(KDIR) M=$(TOP)/$(KMOD_NAME) clean