1 files changed, 224 insertions, 0 deletions
diff --git a/apps/examples/pipe/interlock_test.c b/apps/examples/pipe/interlock_test.c
new file mode 100644
index 000000000..e049a65f6
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+++ b/apps/examples/pipe/interlock_test.c
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+/****************************************************************************
+ * examples/pipe/interlock_test.c
+ *
+ *   Copyright (C) 2008 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 %d bytes of data -- aborting: %d\n", nbytes);
+      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;
+}