The kernel maintains per-process signal data structures to keep track of, signal disposition, blocked signals, and pending signal queues. The process task structure contains appropriate references to these data structures:

struct task_struct {

....
....
....
/* signal handlers */
 struct signal_struct *signal;
 struct sighand_struct *sighand;

 sigset_t blocked, real_blocked;
 sigset_t saved_sigmask; /* restored if set_restore_sigmask() was used */
 struct sigpending pending;

 unsigned long sas_ss_sp;
 size_t sas_ss_size;
 unsigned sas_ss_flags;
  ....
  ....
  ....
  ....

};