sched/signal: Implement SA_NODEFER and SA_RESETHAND

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Change-Id: I9baa72b272c8877022cd94722824f393c7087721

include/signal.h

@@ -249,6 +249,14 @@
                                   * (always assumed) */
 #define SA_NOCLDWAIT    (1 << 2) /* If signo=SIGCHLD, exit status of child
                                   * processes will be discarded */
+#define SA_ONSTACK      (1 << 3) /* Indicates that a registered stack_t
+                                  * will be used */
+#define SA_RESTART      (1 << 4) /* Flag to get restarting signals
+                                  * (which were the default long ago) */
+#define SA_NODEFER      (1 << 5) /* Prevents the current signal from
+                                  * being masked in the handler */
+#define SA_RESETHAND    (1 << 6) /* Clears the handler when the signal
+                                  * is delivered */
 
 /* These are the possible values of the signfo si_code field */
 

sched/signal/sig_deliver.c

@@ -106,8 +106,7 @@ void nxsig_deliver(FAR struct tcb_s *stcb)
        */
 
       savesigprocmask   = stcb->sigprocmask;
-      newsigprocmask    = savesigprocmask | sigq->mask |
-                          SIGNO2SET(sigq->info.si_signo);
+      newsigprocmask    = savesigprocmask | sigq->mask;
       stcb->sigprocmask = newsigprocmask;
 
 #ifndef CONFIG_BUILD_FLAT

sched/signal/sig_dispatch.c

@@ -93,6 +93,11 @@ static int nxsig_queue_action(FAR struct tcb_s *stcb, siginfo_t *info)
 
           sigq->action.sighandler = sigact->act.sa_u._sa_sigaction;
           sigq->mask = sigact->act.sa_mask;
+          if ((sigact->act.sa_flags & SA_NODEFER) == 0)
+            {
+              sigq->mask |= SIGNO2SET(info->si_signo);
+            }
+
           memcpy(&sigq->info, info, sizeof(siginfo_t));
 
           /* Put it at the end of the pending signals list */