Fix places where the errno value was being overwritten by subsequent actions so that the returned errno value was incorrect. From Max Neklyudov.

2 files changed, 40 insertions, 10 deletions

diff --git a/nuttx/fs/vfs/fs_select.c b/nuttx/fs/vfs/fs_select.c
index 6edf2b7c3..47fa65004 100644
--- a/nuttx/fs/vfs/fs_select.c
+++ b/nuttx/fs/vfs/fs_select.c
@@ -103,6 +103,7 @@ int select(int nfds, FAR fd_set *readfds, FAR fd_set *writefds,
            FAR fd_set *exceptfds, FAR struct timeval *timeout)
 {
   struct pollfd *pollset;
+  int errcode;
   int fd;
   int npfds;
   int msec;
@@ -198,6 +199,12 @@ int select(int nfds, FAR fd_set *readfds, FAR fd_set *writefds,
   /* Then let poll do all of the real work. */
 
   ret = poll(pollset, npfds, msec);
+  if (ret < 0)
+    {
+      /* poll() failed! Save the errno value */
+
+      errcode = get_errno();
+    }
 
   /* Now set up the return values */
 
@@ -263,6 +270,16 @@ int select(int nfds, FAR fd_set *readfds, FAR fd_set *writefds,
     }
 
   kmm_free(pollset);
+
+  /* Did poll() fail above? */
+
+  if (ret < 0)
+    {
+      /* Yes.. restore the errno value */
+
+      set_errno(errcode);
+    }
+
   return ret;
 }
 
diff --git a/nuttx/sched/semaphore/sem_timedwait.c b/nuttx/sched/semaphore/sem_timedwait.c
index b7d850728..4d5e58342 100644
--- a/nuttx/sched/semaphore/sem_timedwait.c
+++ b/nuttx/sched/semaphore/sem_timedwait.c
@@ -167,7 +167,7 @@ int sem_timedwait(FAR sem_t *sem, FAR const struct timespec *abstime)
   FAR struct tcb_s *rtcb = (FAR struct tcb_s *)g_readytorun.head;
   irqstate_t flags;
   int        ticks;
-  int        err;
+  int        errcode;
   int        ret = ERROR;
 
   DEBUGASSERT(up_interrupt_context() == false && rtcb->waitdog == NULL);
@@ -179,7 +179,7 @@ int sem_timedwait(FAR sem_t *sem, FAR const struct timespec *abstime)
 #ifdef CONFIG_DEBUG
   if (!abstime || !sem)
     {
-      err = EINVAL;
+      errcode = EINVAL;
       goto errout;
     }
 #endif
@@ -192,7 +192,7 @@ int sem_timedwait(FAR sem_t *sem, FAR const struct timespec *abstime)
   rtcb->waitdog = wd_create();
   if (!rtcb->waitdog)
     {
-      err = ENOMEM;
+      errcode = ENOMEM;
       goto errout;
     }
 
@@ -225,7 +225,7 @@ int sem_timedwait(FAR sem_t *sem, FAR const struct timespec *abstime)
 
   if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
     {
-      err = EINVAL;
+      errcode = EINVAL;
       goto errout_disabled;
     }
 
@@ -233,31 +233,37 @@ int sem_timedwait(FAR sem_t *sem, FAR const struct timespec *abstime)
    * disabled here so that this time stays valid until the wait begins.
    */
 
-  err = clock_abstime2ticks(CLOCK_REALTIME, abstime, &ticks);
+  errcode = clock_abstime2ticks(CLOCK_REALTIME, abstime, &ticks);
 
   /* If the time has already expired return immediately. */
 
-  if (err == OK && ticks <= 0)
+  if (errcode == OK && ticks <= 0)
     {
-      err = ETIMEDOUT;
+      errcode = ETIMEDOUT;
       goto errout_disabled;
     }
 
   /* Handle any time-related errors */
 
-  if (err != OK)
+  if (errcode != OK)
     {
       goto errout_disabled;
     }
 
   /* Start the watchdog */
 
-  err = OK;
+  errcode = OK;
   wd_start(rtcb->waitdog, ticks, (wdentry_t)sem_timeout, 1, getpid());
 
   /* Now perform the blocking wait */
 
   ret = sem_wait(sem);
+  if (ret < 0)
+    {
+      /* sem_wait() failed.  Save the errno value */
+
+      errcode = get_errno();
+    }
 
   /* Stop the watchdog timer */
 
@@ -275,6 +281,13 @@ int sem_timedwait(FAR sem_t *sem, FAR const struct timespec *abstime)
    * cases.
    */
 
+  if (ret < 0)
+    {
+      /* On failure, restore the errno value returned by sem_wait */
+
+      set_errno(errcode);
+    }
+
   return ret;
 
 /* Error exits */
@@ -285,6 +298,6 @@ errout_disabled:
   rtcb->waitdog = NULL;
 
 errout:
-  set_errno(err);
+  set_errno(errcode);
   return ERROR;
 }