linking/hello: fixup Makefiles

It is good to have Makefile and autotool versions for compare. But
the Makefiles should not be intentially horrible. Clean them up to
the level that we teach in the training.

Signed-off-by: John Ogness <john.ogness@linutronix.de>

4 files changed, 65 insertions, 26 deletions

diff --git a/schulung_tools/linking/hello/Makefile b/schulung_tools/linking/hello/Makefile
index a5b4c26..c383eae 100644
--- a/schulung_tools/linking/hello/Makefile
+++ b/schulung_tools/linking/hello/Makefile
@@ -1,33 +1,30 @@
-hello: hello.c libfunc.so
-	$(CROSS_COMPILE)gcc -g -ohello hello.c -L. -lfunc
+CC = $(CROSS_COMPILE)gcc
+LD = $(CROSS_COMPILE)gcc
 
-hello2: hello.c libfunc.a
-	rm -f libfunc.so
-	$(CROSS_COMPILE)gcc -g -ohello2 hello.c -L. -lfunc
+OBJS = hello.o
 
-libfunc.so: libfunc.so.0.0.1
-	ln -s libfunc.so.0.0.1 libfunc.so
+CFLAGS = -g -Wall -Werror -I.
+LDFLAGS = -L. -lfunc
 
-libfunc.so.0.0.1: func1.o func2.o
-	$(CROSS_COMPILE)gcc -shared -olibfunc.so.0.0.1 -Wl,-soname,libfunc.so.0 func1.o func2.o
+hello: $(OBJS) libfunc.so
+	$(CC) -ohello $(OBJS) $(LDFLAGS)
 
-libfunc.a: func1.o func2.o
-	$(CROSS_COMPILE)ar cr libfunc.a func1.o func2.o
-	$(CROSS_COMPILE)ranlib libfunc.a
+hello-static: $(OBJS) libfunc.a
+	rm -f libfunc.so
+	$(CC) -o$@ $(OBJS) $(LDFLAGS)
 
-func1.o: func1.c
-	$(CROSS_COMPILE)gcc -fPIC -g -c func1.c
+%.c: %.o
+	$(CC) -c -o$@ $(CFLAGS) $<
 
-func2.o: func2.c
-	$(CROSS_COMPILE)gcc -fPIC -g -c func2.c
+libfunc.%:
+	$(MAKE) -f Makefile-lib $@
 
-install_lib: libfunc.so.0.0.1
-	echo "/opt/acme/lib" > /etc/ld.so.conf.d/acme.conf
-	mkdir -p /opt/acme/lib
-	cp libfunc.so.0.0.1 /opt/acme/lib
-	ldconfig
+install: hello
+	$(MAKE) -f Makefile-lib install
+	cp $< /usr/bin/
 
 clean:
-	rm -f hello hello2 *.o lib*
+	rm -f hello hello-static $(OBJS)
+	$(MAKE) -f Makefile-lib $@
 
-.PHONY: clean
+.PHONY: install clean
diff --git a/schulung_tools/linking/hello/Makefile-lib b/schulung_tools/linking/hello/Makefile-lib
new file mode 100644
index 0000000..f3ac0de
--- /dev/null
+++ b/schulung_tools/linking/hello/Makefile-lib
@@ -0,0 +1,37 @@
+CC = $(CROSS_COMPILE)gcc
+LD = $(CROSS_COMPILE)gcc
+AR = $(CROSS_COMPILE)ar
+RANLIB = $(CROSS_COMPILE)ranlib
+
+REALNAME = libfunc.so.0.0.1
+SONAME = libfunc.so.0
+LINKERNAME = libfunc.so
+STATICNAME = libfunc.a
+OBJS = func1.o func2.o
+
+CFLAGS = -fPIC -g -Wall -Werror
+LDFLAGS = -shared -Wl,-soname,$(SONAME)
+
+$(LINKERNAME): $(REALNAME)
+	ln -sf $< $@
+
+$(REALNAME): $(OBJS)
+	$(CC) -o$@ $(LDFLAGS) $(OBJS)
+
+$(STATICNAME): $(OBJS)
+	$(AR) cr $@ $(OBJS)
+	$(RANLIB) $@
+
+%.o: %.c
+	$(CC) -c -o$@ $(CFLAGS) $<
+
+install: $(REALNAME)
+	echo "/opt/acme/lib" > /etc/ld.so.conf.d/acme.conf
+	mkdir -p /opt/acme/lib
+	cp $< /opt/acme/lib/
+	ldconfig
+
+clean:
+	rm -f $(OBJS) $(REALNAME) $(SONAME) $(LINKERNAME) $(STATICNAME)
+
+.PHONY: install clean
diff --git a/schulung_tools/linking/hello/func.h b/schulung_tools/linking/hello/func.h
new file mode 100644
index 0000000..cefd769
--- /dev/null
+++ b/schulung_tools/linking/hello/func.h
@@ -0,0 +1,7 @@
+#ifndef FUNC_H
+#define FUNC_H
+
+extern void func1(void);
+extern void func2(void);
+
+#endif /* FUNC_H */
diff --git a/schulung_tools/linking/hello/hello.c b/schulung_tools/linking/hello/hello.c
index 82b8d53..9b8d43a 100644
--- a/schulung_tools/linking/hello/hello.c
+++ b/schulung_tools/linking/hello/hello.c
@@ -1,7 +1,5 @@
 #include <stdio.h>
-
-void func1(void);
-void func2(void);
+#include <func.h>
 
 int main(void)
 {