add assembly targets and rules

Makefile

@@ -4,23 +4,28 @@ OBJ_DIR				=	obj
 BIN_DIR				=	bin
 
 CC					=	gcc
+AS					=	as
 LD					=	ld
 CFLAGS				=	-Wall -I$(INC_DIR)
-LDFLAGS				=	-lcap
+ASFLAGS				=
+LDFLAGS				=	-z noexecstack -lcap
 
 BLACKJACK_SRC		=	main.c process.c
-BLACKJACK_OBJ		:=	$(addprefix $(OBJ_DIR)/,$(patsubst %.c,%.o,$(BLACKJACK_SRC)))
+BLACKJACK_OBJ		:=	$(addprefix $(OBJ_DIR)/,$(patsubst %.s,%.o,$(patsubst %.c,%.o,$(BLACKJACK_SRC))))
 BLACKJACK_SRC		:=	$(addprefix $(SRC_DIR)/,$(BLACKJACK_SRC))
 BLACKJACK_DEPS		=	debug.h process.h
 BLACKJACK_DEPS		:=	$(addprefix $(INC_DIR)/,$(BLACKJACK_DEPS))
 
-DUMMY_TARGET_SRC	=	dummy_target.c
-DUMMY_TARGET_OBJ	:=	$(addprefix $(OBJ_DIR)/,$(patsubst %.c,%.o,$(DUMMY_TARGET_SRC)))
+DUMMY_TARGET_SRC	=	dummy_target.c dummy_destination.s
+DUMMY_TARGET_OBJ	:=	$(addprefix $(OBJ_DIR)/,$(patsubst %.s,%.o,$(patsubst %.c,%.o,$(DUMMY_TARGET_SRC))))
 DUMMY_TARGET_SRC	:=	$(addprefix $(SRC_DIR)/,$(DUMMY_TARGET_SRC))
 
 $(OBJ_DIR)/%.o: $(SRC_DIR)/%.c
 	$(CC) $(CFLAGS) -c -o $@ $<
 
+$(OBJ_DIR)/%.o: $(SRC_DIR)/%.s
+	$(AS) $(ASFLAGS) -o $@ $<
+
 blackjack: $(BLACKJACK_OBJ) $(BLACKJACK_DEPS)
 	$(CC) $(LDFLAGS) -o $(BIN_DIR)/$@ $(BLACKJACK_OBJ)
 
@@ -35,6 +40,7 @@ all: $(TARGETS)
 
 debug: CFLAGS += -DDEBUG -g
 debug: LDFLAGS += -g
+debug: ASFLAGS += -g
 debug: $(TARGETS)
 
 clean:

src/dummy_destination.s

@@ -0,0 +1,13 @@
+    .global hijack_destination
+
+    .text
+hijack_destination:
+    leaq redirect_msg(%rip), %rdi
+    call puts
+.sleep_loop:
+    mov $0x1, %edi
+    call sleep
+    jmp .sleep_loop
+
+    .section rodata
+redirect_msg:   .string "thread has been redirected to this function! cool!"

src/dummy_target.c

@@ -49,11 +49,7 @@ __attribute__((noreturn)) void* slave3_job(void*)
     }
 }
 
-__attribute__((noreturn)) void* hijack_destination(void*)
-{
-    puts("thread has been redirected to this function! cool!");
-    while (1) sleep(1);
-}
+extern void hijack_destination();
 
 int main()
 {