runtime linker

Makefile

all: exef1 exef2 exef3

EI_OSABI:=7
EI_ABIVERSION:=8
EI_PAD:=9

libf1.so:
	echo 'int f(){ return 1; }' | $(CC) -o $@ -shared -Wl,-soname,$@ -x c -
	printf '\x0B' | dd of=$@ bs=1 seek=$(EI_OSABI) count=1 conv=notrunc status=none

libf2.so:
	echo 'int f(){ return 2; }' | $(CC) -o $@ -shared -Wl,-soname,$@ -x c -
	printf '\xff' | dd of=$@ bs=1 seek=$(EI_ABIVERSION) count=1 conv=notrunc status=none

libf3.so:
	echo 'int f(){ return 3; }' | $(CC) -o $@ -shared -Wl,-soname,$@ -x c -
	printf '\xff' | dd of=$@ bs=1 seek=$(EI_PAD) count=1 conv=notrunc status=none

exef1: libf1.so
	echo 'int f(); int main(){printf("%d\\n", f());}' | $(CC) -include stdio.h -o $@ '-Wl,-rpath,$$ORIGIN' -x c - -L. -lf1

exef2: libf2.so
	echo 'int f(); int main(){printf("%d\\n", f());}' | $(CC) -include stdio.h -o $@ '-Wl,-rpath,$$ORIGIN' -x c - -L. -lf2

exef3: libf3.so
	echo 'int f(); int main(){printf("%d\\n", f());}' | $(CC) -include stdio.h -o $@ '-Wl,-rpath,$$ORIGIN' -x c - -L. -lf3

clean:
	rm -f -- *.so exe*