1 files changed, 70 insertions, 1 deletions

diff --git a/nuttx/sched/task_exithook.c b/nuttx/sched/task_exithook.c
index 3bde8fb7a..1106f2885 100644
--- a/nuttx/sched/task_exithook.c
+++ b/nuttx/sched/task_exithook.c
@@ -41,6 +41,7 @@
 
 #include <stdlib.h>
 #include <unistd.h>
+#include <signal.h>
 #include <debug.h>
 #include <errno.h>
 
@@ -188,6 +189,70 @@ static inline void task_onexit(FAR _TCB *tcb, int status)
 #endif
 
 /****************************************************************************
+ * Name: task_sigchild
+ *
+ * Description:
+ *   Send the SIGCHILD signal to the parent thread
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_SCHED_HAVE_PARENT
+static inline void task_sigchild(FAR _TCB *tcb, int status)
+{
+  FAR _TCB *ptcb;
+  siginfo_t info;
+
+  /* Keep things stationary through the following */
+
+  sched_lock();
+
+  /* Get the TCB of the receiving task */
+
+  ptcb = sched_gettcb(tcb->parent);
+  if (!ptcb)
+    {
+      /* The parent no longer exists... bail */
+
+      sched_unlock();
+      return;
+    }
+
+  /* Decrement the number of children from this parent */
+
+  DEBUGASSERT(ptcb->nchildren > 0);
+  ptcb->nchildren--;
+
+  /* Set the parent to an impossible PID.  We do this because under certain
+   * conditions, task_exithook() can be called multiple times.  If this
+   * function is called again, sched_gettcb() will fail on the invalid
+   * parent PID above, nchildren will be decremented once and all will be
+   * well.
+   */
+
+  tcb->parent = INVALID_PROCESS_ID;
+
+  /* Create the siginfo structure.  We don't actually know the cause.  That
+   * is a bug. Let's just say that the child task just exit-ted for now.
+   */
+
+  info.si_signo           = SIGCHLD;
+  info.si_code            = CLD_EXITED;
+  info.si_value.sival_ptr = NULL;
+  info.si_pid             = tcb->pid;
+  info.si_status          = status;
+
+  /* Send the signal.  We need to use this internal interface so that we can
+   * provide the correct si_code value with the signal.
+   */
+
+  (void)sig_received(ptcb, &info);
+  sched_unlock();
+}
+#else
+#  define task_sigchild(tcb,status)
+#endif
+
+/****************************************************************************
  * Name: task_exitwakeup
  *
  * Description:
@@ -195,7 +260,7 @@ static inline void task_onexit(FAR _TCB *tcb, int status)
  *
  ****************************************************************************/
 
-#ifdef CONFIG_SCHED_WAITPID
+#if defined(CONFIG_SCHED_WAITPID) && !defined(CONFIG_SCHED_HAVE_PARENT)
 static inline void task_exitwakeup(FAR _TCB *tcb, int status)
 {
   /* Wakeup any tasks waiting for this task to exit */
@@ -263,6 +328,10 @@ void task_exithook(FAR _TCB *tcb, int status)
 
   task_onexit(tcb, status);
 
+  /* Send SIGCHLD to the parent of the exit-ing task */
+
+  task_sigchild(tcb, status);
+
   /* Wakeup any tasks waiting for this task to exit */
 
   task_exitwakeup(tcb, status);