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/****************************************************************************
* examples/pipe/interlock_test.c
*
* Copyright (C) 2008 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include "pipe.h"
/****************************************************************************
* Definitions
****************************************************************************/
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: null_writer
****************************************************************************/
static void *null_writer(pthread_addr_t pvarg)
{
int fd;
/* Wait a bit */
printf("null_writer: started -- sleeping\n");
sleep(5);
/* Then open the FIFO for write access */
printf("null_writer: Opening FIFO for write access\n");
fd = open(FIFO_PATH2, O_WRONLY);
if (fd < 0)
{
fprintf(stderr, "null_writer: Failed to open FIFO %s for writing, errno=%d\n",
FIFO_PATH2, errno);
return (void*)1;
}
/* Wait a bit more */
printf("null_writer: Opened %s for writing -- sleeping\n", FIFO_PATH2);
sleep(5);
/* Then close the FIFO */
printf("null_writer: Closing %s\n", FIFO_PATH2);
if (close(fd) != 0)
{
fprintf(stderr, "null_writer: close failed: %d\n", errno);
}
sleep(5);
printf("null_writer: Returning success\n");
return (void*)0;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: interlock_test
****************************************************************************/
int interlock_test(void)
{
pthread_t writerid;
void *value;
char data[16];
ssize_t nbytes;
int fd;
int ret;
/* Create a FIFO */
ret = mkfifo(FIFO_PATH2, 0666);
if (ret < 0)
{
fprintf(stderr, "interlock_test: mkfifo failed with errno=%d\n", errno);
return 1;
}
/* Start the null_writer_thread */
printf("interlock_test: Starting null_writer thread\n");
ret = pthread_create(&writerid, NULL, null_writer, (pthread_addr_t)NULL);
if (ret != 0)
{
fprintf(stderr, "interlock_test: Failed to create null_writer thread, error=%d\n", ret);
ret = 2;
goto errout_with_fifo;
}
/* Open one end of the FIFO for reading. This open call should block until the
* null_writer thread opens the other end of the FIFO for writing.
*/
printf("interlock_test: Opening FIFO for read access\n");
fd = open(FIFO_PATH2, O_RDONLY);
if (fd < 0)
{
fprintf(stderr, "interlock_test: Failed to open FIFO %s for reading, errno=%d\n",
FIFO_PATH2, errno);
ret = 3;
goto errout_with_thread;
}
/* Attempt to read one byte from the FIFO. This should return end-of-file because
* the null_writer closes the FIFO without writing anything.
*/
printf("interlock_test: Reading from %s\n", FIFO_PATH2);
nbytes = read(fd, data, 16);
if (nbytes < 0 )
{
fprintf(stderr, "interlock_test: read failed, errno=%d\n", errno);
ret = 4;
goto errout_with_file;
}
else if (ret != 0)
{
fprintf(stderr, "interlock_test: Read %ld bytes of data -- aborting: %d\n",
(long)nbytes, errno);
ret = 5;
goto errout_with_file;
}
/* Close the file */
printf("interlock_test: Closing %s\n", FIFO_PATH2);
if (close(fd) != 0)
{
fprintf(stderr, "interlock_test: close failed: %d\n", errno);
}
/* Wait for null_writer thread to complete */
printf("interlock_test: Waiting for null_writer thread\n");
ret = pthread_join(writerid, &value);
if (ret != 0)
{
fprintf(stderr, "interlock_test: pthread_join failed, error=%d\n", ret);
ret = 6;
goto errout_with_fifo;
}
else
{
printf("interlock_test: writer returned %d\n", (int)value);
if (value != (void*)0)
{
ret = 7;
goto errout_with_fifo;
}
}
/* unlink(FIFO_PATH2); */
printf("interlock_test: Returning success\n");
return 0;
errout_with_file:
if (close(fd) != 0)
{
fprintf(stderr, "interlock_test: close failed: %d\n", errno);
}
errout_with_thread:
pthread_detach(writerid);
pthread_cancel(writerid);
errout_with_fifo:
/* unlink(FIFO_PATH2); */
printf("interlock_test: Returning %d\n", ret);
return ret;
}
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