Initial implementation of aio_suspend()

2 files changed, 177 insertions, 2 deletions

diff --git a/nuttx/libc/aio/Make.defs b/nuttx/libc/aio/Make.defs
index 2ec441a3a..f7622f25e 100644
--- a/nuttx/libc/aio/Make.defs
+++ b/nuttx/libc/aio/Make.defs
@@ -37,8 +37,8 @@ ifeq ($(CONFIG_LIBC_AIO),y)
 
 # Add the asynchronous I/O C files to the build
 
-CSRCS += aio_read.c aio_write.c aio_return.c aio_error.c
-CSRCS += aio_signal.c
+CSRCS += aio_error.c aio_read.c aio_return.c aio_signal.c aio_write.c
+CSRCS += aio_suspend.c
 
 ifneq ($(CONFIG_PTHREAD_DISABLE),y)
 CSRCS += lio_listio.c
diff --git a/nuttx/libc/aio/aio_suspend.c b/nuttx/libc/aio/aio_suspend.c
new file mode 100644
index 000000000..625d597f8
--- /dev/null
+++ b/nuttx/libc/aio/aio_suspend.c
@@ -0,0 +1,175 @@
+/****************************************************************************
+ * libc/aio/aio_suspend.c
+ *
+ *   Copyright (C) 2014 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 <signal.h>
+#include <aio.h>
+#include <assert.h>
+#include <errno.h>
+
+#ifndef CONFIG_LIBC_AIO
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+/* Configuration ************************************************************/
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Variables
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Variables
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: aio_read
+ *
+ * Description:
+ *   The aio_suspend() function suspends the calling thread until at least
+ *   one of the asynchronous I/O operations referenced by the 'list' argument
+ *   has completed, until a signal interrupts the function, or, if 'timeout'
+ *   is not NULL, until the time interval specified by 'timeout' has passed.
+ *   If any of the aiocb structures in the list correspond to completed
+ *   asynchronous I/O operations (that is, the error status for the
+ *   operation is not equal to EINPROGRESS) at the time of the call, the
+ *   function returns without suspending the calling thread.
+ *
+ *   Each aiocb structure pointed to must have been used in initiating an
+ *   asynchronous I/O request via aio_read(), aio_write(), or lio_listio().
+ *   This array may contain NULL pointers, which are ignored. If this
+ *   array contains pointers that refer to aiocb structures that have not
+ *   been used in submitting asynchronous I/O, the effect is undefined. 
+ *
+ * Input Parameters:
+ *   list    - An array of pointers to asynchronous I/O control blocks.
+ *   nent    - The number of elements in the array.
+ *   aiocbp  - A pointer to an array
+ *   timeout - If not NULL, this parameter is pointer to a timespec
+ *             structure that determines a timeout on the operation.  If
+ *             the time referred to timeout passes before any of the I/O
+ *             operations referenced by list are completed, then
+ *             aio_suspend() returns with an error. 
+ *
+ * Returned Value:
+ *   If the aio_suspend() function returns after one or more asynchronous
+ *   I/O operations have completed, the function returns zero. Otherwise,
+ *   the function returns a value of -1 and sets errno to indicate the
+ *   error.  The application may determine which asynchronous I/O completed
+ *   by scanning the associated error and return status using aio_error()
+ *   and aio_return(), respectively. 
+ *
+ *   The aio_suspend() function will fail if:
+ *
+ *     EAGAIN - No asynchronous I/O indicated in the list referenced by
+ *              list completed in the time interval indicated by timeout.
+ *     EINTR  - A signal interrupted the aio_suspend() function.
+ *
+ ****************************************************************************/
+
+int aio_suspend(FAR const struct aiocb *const list[], int nent,
+                FAR const struct timespec *timeout)
+{
+  sigset_t set;
+  int ret;
+  int i;
+
+  DEBUGASSERT(aiocbp);
+
+  /* Create the signal set */
+
+  sigemptyset(&set);
+  sigaddset(&set, SIGPOLL);
+
+  /* Lock the scheduler so that no I/O events can complete on the worker
+   * thread until we set our wait set up.  Pre-emption will, of course, be
+   * re-enabled while we are waiting for the signal.
+   */
+
+  sched_lock();
+
+  /* Check each entry in the list.  Break out of the loop if any entry
+   * has completed.
+   */
+
+  for (i = 0; i < nent; i++)
+    {
+      /* Check if the I/O has completed */
+
+      if (list[i] && list[i]->aio_result != -EINPROGRESS)
+        {
+          /* Yes, return success */
+
+          sched_unlock();
+          return OK;
+        }
+
+      /* If the caller has a signal notification setup, add that to the
+       * signals we will wait for.
+       */
+
+      if (aiocbp->aio_sigevent.sigev_notify == SIGEV_SIGNAL)
+        {
+          sigaddset(&set, aiocbp->aio_sigevent.sigev_signo);
+        }
+    }
+
+  /* Then wait.  sigtimedwait() will return the signal number that cause the
+   * error.  It will set errno appropriately for this function on errors.
+   */
+
+  ret = sigtimedwait(&set, NULL, &timeout)
+  sched_unlock();
+  return ret >= 0 ? OK : ERROR;
+}
+
+#endif /* CONFIG_LIBC_AIO */