incubator-nuttx/sched/group/group_setupidlefiles.c

119 lines
3.5 KiB
C

/****************************************************************************
* sched/group/group_setupidlefiles.c
*
* 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
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <sched.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/fs/fs.h>
#include <nuttx/net/net.h>
#include <nuttx/trace.h>
#include "group/group.h"
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: group_setupidlefiles
*
* Description:
* Configure the idle thread's TCB.
*
* Input Parameters:
* None.
*
* Returned Value:
* 0 is returned on success; a negated errno value is returned on a
* failure.
*
****************************************************************************/
int group_setupidlefiles(void)
{
#if defined(CONFIG_DEV_CONSOLE) || defined(CONFIG_DEV_NULL)
int fd;
#endif
sched_trace_begin();
/* Open stdin, dup to get stdout and stderr. This should always
* be the first file opened and, hence, should always get file
* descriptor 0.
*/
#if defined(CONFIG_DEV_CONSOLE) || defined(CONFIG_DEV_NULL)
# ifdef CONFIG_DEV_CONSOLE
fd = nx_open("/dev/console", O_RDWR);
# else
fd = nx_open("/dev/null", O_RDWR);
# endif
if (fd == 0)
{
/* Successfully opened stdin (fd == 0) */
nx_dup2(0, 1);
nx_dup2(0, 2);
}
else
{
/* We failed to open stdin OR for some reason, we opened
* it and got some file descriptor other than 0.
*/
if (fd > 0)
{
sinfo("Open stdin fd: %d\n", fd);
nx_close(fd);
}
else
{
serr("ERROR: Failed to open stdin: %d\n", fd);
}
sched_trace_end();
return -ENFILE;
}
#else
/* This configuration can confuse user programs and libraries.
* Eg. a program which opens a file and then prints something to
* STDERR_FILENO (2) can end up with something undesirable if the
* file descriptor for the file happens to be 2.
* It's a common practice to keep 0-2 always open even if they are
* /dev/null to avoid that kind of problems. Thus the following warning.
*/
# warning file descriptors 0-2 are not opened
#endif /* defined(CONFIG_DEV_CONSOLE) || defined(CONFIG_DEV_NULL) */
sched_trace_end();
return OK;
}