new_contents: import angr
  import logging
  
  l = logging.getLogger('angr.procedures.linux_kernel.cwd')
  
  class getcwd(angr.SimProcedure):
      def run(self, buf, size):
          cwd = self.state.fs.cwd
          size = self.state.solver.If(size-1 > len(cwd), len(cwd), size-1)
          try:
              self.state.memory.store(buf, cwd, size=size)
              self.state.memory.store(buf + size, '\0')
          except angr.errors.SimSegfaultException:
              return 0
          else:
              return buf
  
  class chdir(angr.SimProcedure):
      def run(self, buf):
          cwd = self.state.mem[buf].string
          l.info('chdir(%r)', cwd)
          self.state.fs.cwd = cwd
          return 0
  
subject: Add implementations of chdir/getcwd