Question

Is it possible to write a program in C that upon execution deletes itself (the binary) and then terminates successfully. If so, what’s the easiest way of doing this?

Answer 1

Yes.

#include <unistd.h>
int main(int argc, char* argv[])
{
  return unlink(argv[0]);
}

(Tested and works.)

Note that if argv[0] does not point to the binary (rewritten by caller) this will not work.
Similarly if run through a symlink then the symlink, not the binary, will be deleted.

Also if the file has multiple hard links, only the called link will be removed.