Fix IRQ-related bugs, fix serial read logic, add fgets

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@51 42af7a65-404d-4744-a932-0658087f49c3

1 files changed, 9 insertions, 0 deletions

diff --git a/nuttx/sched/sem_wait.c b/nuttx/sched/sem_wait.c
index 7893b39ba..4d82dd41a 100644
--- a/nuttx/sched/sem_wait.c
+++ b/nuttx/sched/sem_wait.c
@@ -103,6 +103,15 @@ int sem_wait(sem_t *sem)
   int        ret = ERROR;
   irqstate_t saved_state;
 
+  /* This API should not be called from interrupt handlers */
+
+  if (up_interrupt_context())
+    {
+      /* We do not want to set the errno in this case */
+
+      return ERROR;
+    }
+
   /* Assume any errors reported are due to invalid arguments. */
 
   *get_errno_ptr() = EINVAL;