Makefile

CC ?= cc
CFLAGS ?= -O -Wall -Wextra -Wformat-security -D_FORTIFY_SOURCE=2
CFLAGS += -std=c99 -D_POSIX_C_SOURCE=200809L
LDFLAGS += -fPIC -shared

# FreeBSD puts the openvpn header in a different location unknown to clang
IPATH_FREEBSD = /usr/local/include/

# Add OS Specific build flags
UNAME_S := $(shell uname -s)
ifeq ($(UNAME_S),FreeBSD)
	# Add the include path for openvpn-plugin.h
	CFLAGS += -I$(IPATH_FREEBSD) 
	# Ensure the signals we need are visible
	CFLAGS += -D_XOPEN_SOURCE=600
	
	# BSD uses Clang - we need to check for stack-protector-strong flag 
	STACK_PROTECT := $(shell $(CC) --help | grep stack-protector-strong)
	ifneq ($(filter %stack-protector-strong, $(STACK_PROTECT)),)
		CFLAGS += -fstack-protector-strong 
	endif
else
	STACK_PROTECT := $(shell $(CC) -dumpspecs | grep stack-protector-strong)
	ifneq ($(findstring fstack-protector-strong, $(STACK_PROTECT)),)
		CFLAGS += -fstack-protector-strong
	endif
endif

# Detect Ubuntu to be able to include a different openvpn header file
LSB_RELEASE_BIN := $(shell command -v lsb_release 2> /dev/null)
ifndef LSB_RELEASE_BIN
$(warning lsb_release is not available on the system, skipping OS detection)
else
	ifneq ($(findstring Ubuntu, $(shell lsb_release -si)),)
		CFLAGS += -DOS_UBUNTU
	endif
endif


$(info Building 4 for $(UNAME_S))

# Output Files
SRC 	= $(wildcard *.c)
OUT	= $(SRC:%.c=%.so)

%.so: %.c
	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $<

all: plugin

plugin: $(OUT)

clean:
	rm -f *.so