nuttx/drivers/misc/dev_null.c
Nathan Hartman 1867bc2210 Fix compiler warnings (-Wunused-parameter) in various functions
Fixes the -Wunused-parameter warning in:
* group/group_signal.c: group_signal()
* irq/irq_unexpectedisr.c: irq_unexpected_isr()
* task/task_spawn.c: nxtask_spawn_proxy()
* timer/timer_getoverrun.c: timer_getoverrun()
* misc/dev_null.c: devnull_read(), devnull_write(), devnull_poll()
* misc/dev_zero.c: devzero_read(), devzero_write(), devzero_poll()
* syslog/syslog_channel.c: syslog_default_write()
* syslog/syslog_device.c: syslog_dev_flush()
* grp/lib_initgroups.c: initgroups()
* misc/lib_mknod.c: mknod()
* misc/lib_glob.c: ignore_err()
* pthread/pthread_barrierinit.c: pthread_barrier_init()
* pthread/pthread_atfork.c: pthread_atfork()
* semaphore/sem_init.c: nxsem_init()
* stream/lib_nullinstream.c: nullinstream_getc()
* stream/lib_nulloutstream.c: nulloutstream_putc()
* stream/lib_libnoflush.c: lib_noflush()
* stream/lib_libsnoflush.c: lib_snoflush()
* string/lib_strerror.c: strerror()
* time/lib_gettimeofday.c: gettimeofday()
* time/lib_settimeofday.c: settimeofday()
* unistd/lib_pathconf.c: fpathconf(), pathconf()
* unistd/lib_getrusage.c: getrusage()
* unistd/lib_setrlimit.c: setrlimit()
* unistd/lib_getrlimit.c: getrlimit()
* unistd/lib_setpriority.c: setpriority()
2022-07-12 11:42:34 +08:00

134 lines
4.2 KiB
C

/****************************************************************************
* drivers/misc/dev_null.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 <sys/types.h>
#include <stdbool.h>
#include <string.h>
#include <poll.h>
#include <errno.h>
#include <nuttx/semaphore.h>
#include <nuttx/fs/fs.h>
#include <nuttx/drivers/drivers.h>
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
static ssize_t devnull_read(FAR struct file *filep, FAR char *buffer,
size_t buflen);
static ssize_t devnull_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen);
static int devnull_poll(FAR struct file *filep, FAR struct pollfd *fds,
bool setup);
/****************************************************************************
* Private Data
****************************************************************************/
static const struct file_operations devnull_fops =
{
NULL, /* open */
NULL, /* close */
devnull_read, /* read */
devnull_write, /* write */
NULL, /* seek */
NULL, /* ioctl */
devnull_poll /* poll */
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
, NULL /* unlink */
#endif
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: devnull_read
****************************************************************************/
static ssize_t devnull_read(FAR struct file *filep, FAR char *buffer,
size_t len)
{
UNUSED(filep);
UNUSED(buffer);
UNUSED(len);
return 0; /* Return EOF */
}
/****************************************************************************
* Name: devnull_write
****************************************************************************/
static ssize_t devnull_write(FAR struct file *filep, FAR const char *buffer,
size_t len)
{
UNUSED(filep);
UNUSED(buffer);
return len; /* Say that everything was written */
}
/****************************************************************************
* Name: devnull_poll
****************************************************************************/
static int devnull_poll(FAR struct file *filep, FAR struct pollfd *fds,
bool setup)
{
UNUSED(filep);
if (setup)
{
fds->revents |= (fds->events & (POLLIN | POLLOUT));
if (fds->revents != 0)
{
nxsem_post(fds->sem);
}
}
return OK;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: devnull_register
*
* Description:
* Register /dev/null
*
****************************************************************************/
void devnull_register(void)
{
register_driver("/dev/null", &devnull_fops, 0666, NULL);
}