Minor simplication to last commit; Update TODO list

TODO

@@ -11,7 +11,7 @@ nuttx/
 
  (13)  Task/Scheduler (sched/)
   (1)  Memory Management (mm/)
-  (4)  Signals (sched/signal, arch/)
+  (3)  Signals (sched/signal, arch/)
   (2)  pthreads (sched/pthread)
   (0)  Message Queues (sched/mqueue)
   (6)  Kernel/Protected Build
@@ -360,17 +360,6 @@ o Signals (sched/signal, arch/)
   Status:      Open
   Priority:    Low. Even if there are only 31 usable signals, that is still a lot.
 
-  Title:       THREAD COMMON SIGNAL HANDLING
-  Description: Signal handlers are assigned on a per thread basis.  Signal lists
-               and data structures are a part of the TCB.  This is incorrect.
-               Signal handlers are a global property of the task group:  The
-               main thread and all of its child threads.  Signal handlers for
-               all threads should be attach-able from the main thread, for
-               example.
-  Status:      Open
-  Priority:    Medium.  This is a pretty big violation of the signal handling
-               principles.
-
 o pthreads (sched/pthreads)
   ^^^^^^^^^^^^^^^^^
 

sched/group/group_signal.c

@@ -89,12 +89,11 @@ struct group_signal_s
 static int group_signal_handler(pid_t pid, FAR void *arg)
 {
   FAR struct group_signal_s *info = (FAR struct group_signal_s *)arg;
-  FAR struct task_group_s *group;
   FAR struct tcb_s *tcb;
   FAR sigactq_t *sigact;
   int ret;
 
-  DEBUGASSERT(info);
+  DEBUGASSERT(tcb != NULL && tcb->group != NULL && info != NULL);
 
   /* Get the TCB associated with the group member */
 
@@ -154,10 +153,7 @@ static int group_signal_handler(pid_t pid, FAR void *arg)
 
           /* Is there also a action associated with the task group? */
 
-          group = tcb->group;
-          DEBUGASSERT(group != NULL);
-
-          sigact = sig_findaction(group, info->siginfo->si_signo);
+          sigact = sig_findaction(tcb->group, info->siginfo->si_signo);
           if (sigact)
             {
               /* Yes.. then use this thread.  The requirement is this:

sched/signal/sig_dispatch.c

@@ -72,20 +72,17 @@
 
 static int sig_queueaction(FAR struct tcb_s *stcb, siginfo_t *info)
 {
-  FAR struct task_group_s *group;
   FAR sigactq_t *sigact;
   FAR sigq_t    *sigq;
   irqstate_t     flags;
   int            ret = OK;
 
   sched_lock();
+  DEBUGASSERT(stcb != NULL && stcb->group != NULL);
 
   /* Find the group sigaction associated with this signal */
 
-  DEBUGASSERT(stcb != NULL && stcb->group != NULL);
-
-  group = stcb->group;
-  sigact = sig_findaction(group, info->si_signo);
+  sigact = sig_findaction(stcb->group, info->si_signo);
 
   /* Check if a valid signal handler is available and if the signal is
    * unblocked.  NOTE:  There is no default action.
@@ -202,7 +199,7 @@ static FAR sigpendq_t *sig_findpendingsignal(FAR struct task_group_s *group,
   FAR sigpendq_t *sigpend = NULL;
   irqstate_t flags;
 
-  DEBUGASSERT(group);
+  DEBUGASSERT(group != NULL);
 
   /* Pending sigals can be added from interrupt level. */
 
@@ -232,13 +229,14 @@ static FAR sigpendq_t *sig_findpendingsignal(FAR struct task_group_s *group,
 static FAR sigpendq_t *sig_addpendingsignal(FAR struct tcb_s *stcb,
                                             FAR siginfo_t *info)
 {
-  FAR struct task_group_s *group = stcb->group;
+  FAR struct task_group_s *group;
   FAR sigpendq_t *sigpend;
   irqstate_t flags;
 
-  DEBUGASSERT(group);
+  DEBUGASSERT(stcb != NULL && stcb->group != NULL);
+  group = stcb->group;
 
-  /* Check if the signal is already pending */
+  /* Check if the signal is already pending for the group */
 
   sigpend = sig_findpendingsignal(group, info->si_signo);
   if (sigpend)
@@ -248,7 +246,7 @@ static FAR sigpendq_t *sig_addpendingsignal(FAR struct tcb_s *stcb,
       memcpy(&sigpend->info, info, sizeof(siginfo_t));
     }
 
-  /* No... There is nothing pending for this signo */
+  /* No... There is nothing pending in the group for this signo */
 
   else
     {
@@ -261,7 +259,7 @@ static FAR sigpendq_t *sig_addpendingsignal(FAR struct tcb_s *stcb,
 
           memcpy(&sigpend->info, info, sizeof(siginfo_t));
 
-          /* Add the structure to the pending signal list */
+          /* Add the structure to the group pending signal list */
 
           flags = enter_critical_section();
           sq_addlast((FAR sq_entry_t *)sigpend, &group->tg_sigpendingq);