1 files changed, 239 insertions, 0 deletions
diff --git a/nuttx/fs/fs_select.c b/nuttx/fs/fs_select.c
new file mode 100644
index 000000000..e40c5bc13
--- /dev/null
+++ b/nuttx/fs/fs_select.c
@@ -0,0 +1,239 @@
+/****************************************************************************
+ * fs/fs_select.c
+ *
+ *   Copyright (C) 2008-2009, 2012 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/select.h>
+
+#include <string.h>
+#include <poll.h>
+#include <time.h>
+#include <errno.h>
+#include <assert.h>
+#include <debug.h>
+
+#include <nuttx/kmalloc.h>
+#include <nuttx/fs/fs.h>
+
+#include "fs_internal.h"
+
+#ifndef CONFIG_DISABLE_POLL
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: select
+ *
+ * Description:
+ *   select() allows a program to monitor multiple file descriptors, waiting
+ *   until one or more of the file descriptors become "ready" for some class
+ *   of I/O operation (e.g., input possible).  A file descriptor is
+ *   considered  ready if it is possible to perform the corresponding I/O
+ *   operation (e.g., read(2)) without blocking.
+ *
+ *   NOTE: poll() is the fundamental API for performing such monitoring
+ *   operation under NuttX.  select() is provided for compatibility and
+ *   is simply a layer of added logic on top of poll().  As such, select()
+ *   is more wasteful of resources and poll() is the recommended API to be
+ *   used.
+ *
+ * Input parameters:
+ *   nfds - the maximum fd number (+1) of any descriptor in any of the
+ *     three sets.
+ *   readfds - the set of descriptions to monitor for read-ready events
+ *   writefds - the set of descriptions to monitor for write-ready events
+ *   exceptfds - the set of descriptions to monitor for error events
+ *   timeout - Return at this time if none of these events of interest
+ *     occur.
+ *
+ *  Return:
+ *   0: Timer expired
+ *  >0: The number of bits set in the three sets of descriptors
+ *  -1: An error occurred (errno will be set appropriately)
+ *
+ ****************************************************************************/
+
+int select(int nfds, FAR fd_set *readfds, FAR fd_set *writefds,
+           FAR fd_set *exceptfds, FAR struct timeval *timeout)
+{
+  struct pollfd *pollset;
+  int fd;
+  int npfds;
+  int msec;
+  int ndx;
+  int ret;
+
+  /* Allocate the descriptor list for poll() */
+
+  pollset = (struct pollfd *)kzalloc(nfds * sizeof(struct pollfd));
+  if (!pollset)
+    {
+      set_errno(ENOMEM);
+      return ERROR;
+    }
+
+  /* Initialize the descriptor list for poll() */
+
+  for (fd = 0, npfds = 0; fd < nfds; fd++)
+    {
+      int incr = 0;
+
+      /* The readfs set holds the set of FDs that the caller can be assured
+       * of reading from without blocking.  Note that POLLHUP is included as
+       * a read-able condition.  POLLHUP will be reported at the end-of-file
+       * or when a connection is lost.  In either case, the read() can then
+       * be performed without blocking.
+       */
+
+      if (readfds && FD_ISSET(fd, readfds))
+        {
+          pollset[npfds].fd      = fd;
+          pollset[npfds].events |= POLLIN;
+          incr                   = 1;
+        }
+
+      /* The writefds set holds the set of FDs that the caller can be assured
+       * of writing to without blocking.
+       */
+
+      if (writefds && FD_ISSET(fd, writefds))
+        {
+          pollset[npfds].fd      = fd;
+          pollset[npfds].events |= POLLOUT;
+          incr                   = 1;
+        }
+
+      /* The exceptfds set holds the set of FDs that are watched for exceptions */
+
+      if (exceptfds && FD_ISSET(fd, exceptfds))
+        {
+          pollset[npfds].fd      = fd;
+          incr                   = 1;
+        }
+
+      npfds += incr;
+    }
+
+  /* Convert the timeout to milliseconds */
+
+  msec = timeout->tv_sec * 1000 + timeout->tv_usec / 1000;
+
+  /* Then let poll do all of the real work. */
+
+  ret = poll(pollset, npfds, msec);
+
+  /* Now set up the return values */
+
+  if (readfds)
+    {
+      memset(readfds, 0, sizeof(fd_set));
+    }
+
+  if (writefds)
+    {
+      memset(writefds, 0, sizeof(fd_set));
+    }
+
+  if (exceptfds)
+    {
+      memset(exceptfds, 0, sizeof(fd_set));
+    }
+
+  /* Convert the poll descriptor list back into selects 3 bitsets */
+
+  if (ret > 0)
+    {
+      ret = 0;
+      for (ndx = 0; ndx < npfds; ndx++)
+        {
+          /* Check for read conditions.  Note that POLLHUP is included as a
+           * read condition.  POLLHUP will be reported when no more data will
+           * be available (such as when a connection is lost).  In either
+           * case, the read() can then be performed without blocking.
+           */
+
+          if (readfds)
+            {
+              if (pollset[ndx].revents & (POLLIN|POLLHUP))
+                {
+                  FD_SET(pollset[ndx].fd, readfds);
+                  ret++;
+                }
+            }
+
+          /* Check for write conditions */
+
+          if (writefds)
+            {
+              if (pollset[ndx].revents & POLLOUT)
+                {
+                  FD_SET(pollset[ndx].fd, writefds);
+                  ret++;
+                }
+            }
+
+          /* Check for exceptions */
+
+          if (exceptfds)
+            {
+              if (pollset[ndx].revents & POLLERR)
+                {
+                  FD_SET(pollset[ndx].fd, exceptfds);
+                  ret++;
+                }
+            }
+        }
+    }
+
+  kfree(pollset);
+  return ret;
+}
+
+#endif /* CONFIG_DISABLE_POLL */
+