Please make sure that you have read our rules. And note:
(6) Do not post classroom or homework problems.
But we sometimes bend this rule when a student has done a lot of work. So I'll make a few comments based on a quick scan of your code. This line of code:
while(1) sleep(1);//run
is dangerous. Why do you have it? I would delete it. If you meant to do something like:
while (1) { List() ; sleep(1) ; }
then you have the fork() in the wrong place. You need to fork() once at the beginning of the program. At present, your program is running List() once and then falling into your infinite sleep loop. You have some re-writing to do.
wait(30);
is illegal and also dangerous. I don't even know what you want to happen there. The last thing you do in List is to ignore some signals. You should ignore signals earlier. If you put List() in a loop, you need to move the signal calls to near the beginning somewhere.
Your instructor probably told you to check if the parent pid is 1, but your instructor is wrong. That is not the definition of a daemon. As it happens, you can probably get away with test you have. But the definition of a daemon is a program with no controlling terminal. You could check that by attempting to open /dev/tty. A daemon must fail but a non-damon must succeed.