From 75ee14b8629082804de22d63734cbe36c95909cf Mon Sep 17 00:00:00 2001
From: patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3>
Date: Tue, 29 Nov 2011 18:21:52 +0000
Subject: [PATCH] Fix handling of NULL pointer in sig_timedwait()

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@4129 42af7a65-404d-4744-a932-0658087f49c3
---
 ChangeLog             |  4 +++-
 sched/sig_timedwait.c | 14 ++++++++++----
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index de0f8872fa..523d11ddd7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -2224,4 +2224,6 @@
 	  board.
 	* include/sys/types.h:  wchar_t is a builtin type in C++ and its
 	  declaration can cause errors with certain C++ compilers.
-
+	* sched/sig_timedwait.c:  Fix signal handling with the returned info
+	  is NULL.  Before this change, it would derefence a NULL pointer
+	  in this case.
diff --git a/sched/sig_timedwait.c b/sched/sig_timedwait.c
index dbbf444dcc..2d9afaab11 100644
--- a/sched/sig_timedwait.c
+++ b/sched/sig_timedwait.c
@@ -277,12 +277,18 @@ int sigtimedwait(FAR const sigset_t *set, FAR struct siginfo *info,
       if (info)
         {
           memcpy(info, &rtcb->sigunbinfo, sizeof(struct siginfo));
+
+          /* The return value is the number of the signal that awakened us */
+
+          ret = info->si_signo;
+        }
+      else
+        {
+          /* We don't know which signal awakened us.  This is probably a bug. */
+
+          ret = 0;
         }
       irqrestore(saved_state);
-
-      /* The return value is the number of the signal that awakened us */
-
-      ret = info->si_signo;
    }
    sched_unlock();