fs/vfs/fd_open.c: fs_fdopen() must not set errno

Functions within the OS must never set the errno value.  fs_fdopen() was setting the errno value.  Now, after some parameter changes, it reports errors via a negated errno integer return value as do most all other internal OS functions.

fs/vfs/fs_fdopen.c

@@ -1,35 +1,20 @@
 /****************************************************************************
  * fs/vfs/fs_fdopen.c
  *
- *   Copyright (C) 2007-2014, 2017 Gregory Nutt. All rights reserved.
- *   Author: Gregory Nutt <gnutt@nuttx.org>
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
+ *   http://www.apache.org/licenses/LICENSE-2.0
  *
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in
- *    the documentation and/or other materials provided with the
- *    distribution.
- * 3. Neither the name NuttX nor the names of its contributors may be
- *    used to endorse or promote products derived from this software
- *    without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
- * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
- * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
- * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
- * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
- * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
- * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
- * POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
  *
  ****************************************************************************/
 
@@ -124,11 +109,11 @@ static inline int fs_checkfd(FAR struct tcb_s *tcb, int fd, int oflags)
  *
  ****************************************************************************/
 
-FAR struct file_struct *fs_fdopen(int fd, int oflags, FAR struct tcb_s *tcb)
+int fs_fdopen(int fd, int oflags, FAR struct tcb_s *tcb,
+              FAR struct file_struct **filep)
 {
   FAR struct streamlist *slist;
   FAR FILE              *stream;
-  int                    errcode = OK;
   int                    ret;
   int                    i;
 
@@ -136,7 +121,7 @@ FAR struct file_struct *fs_fdopen(int fd, int oflags, FAR struct tcb_s *tcb)
 
   if (fd < 0)
     {
-      errcode = EBADF;
+      ret = -EBADF;
       goto errout;
     }
 
@@ -170,7 +155,7 @@ FAR struct file_struct *fs_fdopen(int fd, int oflags, FAR struct tcb_s *tcb)
 #else
       /* No networking... it is just a bad descriptor */
 
-      errcode = EBADF;
+      ret = -EBADF;
       goto errout;
 #endif
     }
@@ -190,7 +175,6 @@ FAR struct file_struct *fs_fdopen(int fd, int oflags, FAR struct tcb_s *tcb)
     {
       /* No... return the reported error */
 
-      errcode = -ret;
       goto errout;
     }
 
@@ -207,7 +191,6 @@ FAR struct file_struct *fs_fdopen(int fd, int oflags, FAR struct tcb_s *tcb)
   ret = nxsem_wait(&slist->sl_sem);
   if (ret < 0)
     {
-      errcode = -ret;
       goto errout;
     }
 
@@ -235,7 +218,7 @@ FAR struct file_struct *fs_fdopen(int fd, int oflags, FAR struct tcb_s *tcb)
 
           if (!stream->fs_bufstart)
             {
-              errcode = ENOMEM;
+              ret = -ENOMEM;
               goto errout_with_sem;
             }
 
@@ -262,13 +245,18 @@ FAR struct file_struct *fs_fdopen(int fd, int oflags, FAR struct tcb_s *tcb)
           stream->fs_oflags  = (uint16_t)oflags;
 
           nxsem_post(&slist->sl_sem);
-          return stream;
+          if (filep != NULL)
+            {
+              *filep = stream;
+            }
+
+          return OK;
         }
     }
 
   /* No free stream available.. report ENFILE */
 
-  errcode = ENFILE;
+  ret = -ENFILE;
 
 #if !defined(CONFIG_STDIO_DISABLE_BUFFERING) && CONFIG_STDIO_BUFFER_SIZE > 0
 errout_with_sem:
@@ -276,6 +264,10 @@ errout_with_sem:
   nxsem_post(&slist->sl_sem);
 
 errout:
-  set_errno(errcode);
-  return NULL;
+  if (filep != NULL)
+    {
+      *filep = NULL;
+    }
+
+  return ret;
 }