Finish dup logic for open files; fix bug in sigtimedwait(), would return wrong signo value if the signal was already pending

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5517 42af7a65-404d-4744-a932-0658087f49c3

builtin/Kconfig

@@ -12,4 +12,19 @@ config BUILTIN
 		to support built-in applications in the NuttShell (NSH).
 
 if BUILTIN
+
+	config APPS_BINDIR
+	bool "BINFS File System"
+	default n
+	---help---
+		The BINFS file system is current just a toy.  The BINFS may, for example,
+		be mount at /bin.  Then all of the built-in applications will appear as
+		executable file in /bin if you list them from NSH like:
+
+		nsh> ls -l /bin
+
+		At present, the BINFS supports nothing more than that.  It is planned,
+		however, to support execution of the builtin applications from BINFS as
+		well (via a binfmt/ loader).  However, that is down the road.
+
 endif

builtin/binfs.c

@@ -85,6 +85,8 @@ static int     binfs_close(FAR struct file *filep);
 static ssize_t binfs_read(FAR struct file *filep, char *buffer, size_t buflen);
 static int     binfs_ioctl(FAR struct file *filep, int cmd, unsigned long arg);
 
+static int     binfs_dup(FAR const struct file *oldp, FAR struct file *newp);
+
 static int     binfs_opendir(struct inode *mountpt, const char *relpath,
                              struct fs_dirent_s *dir);
 static int     binfs_readdir(struct inode *mountpt, struct fs_dirent_s *dir);
@@ -120,7 +122,7 @@ const struct mountpt_operations binfs_operations =
   binfs_ioctl,       /* ioctl */
 
   NULL,              /* sync */
-  NULL,              /* dup */
+  binfs_dup,         /* dup */
 
   binfs_opendir,     /* opendir */
   NULL,              /* closedir */
@@ -296,6 +298,39 @@ static int binfs_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
   return -ENOTTY;
 }
 
+/****************************************************************************
+ * Name: binfs_dup
+ *
+ * Description:
+ *   Duplicate open file data in the new file structure.
+ *
+ ****************************************************************************/
+
+static int binfs_dup(FAR const struct file *oldp, FAR struct file *newp)
+{
+  struct binfs_state_s *bm;
+  int ret = -ENOSYS;
+
+  fvdbg("Dup %p->%p\n", oldp, newp);
+
+  /* Sanity checks */
+
+  DEBUGASSERT(oldp->f_priv == NULL && oldp->f_inode != NULL);
+
+  /* mountpoint private data from the inode reference from the file
+   * structure
+   */
+
+  bm = (struct binfs_state_s*)oldp->f_inode->i_private;
+  DEBUGASSERT(bm != NULL);
+
+  /* Opening of elements within the pseudo-file system is not yet supported
+   * and, hence, neither is dup'ing the opened file.
+   */
+
+  return ret;
+}
+
 /****************************************************************************
  * Name: binfs_opendir
  *