rearrange to allow internal/private use of ares_writev to any system

that lacks the writev function.

1 files changed, 77 insertions, 0 deletions

diff --git a/ares_writev.c b/ares_writev.c
new file mode 100644
index 0000000..045373b
--- /dev/null
+++ b/ares_writev.c
@@ -0,0 +1,77 @@
+
+/* $Id$ */
+
+/* Copyright 1998 by the Massachusetts Institute of Technology.
+ *
+ * Permission to use, copy, modify, and distribute this
+ * software and its documentation for any purpose and without
+ * fee is hereby granted, provided that the above copyright
+ * notice appear in all copies and that both that copyright
+ * notice and this permission notice appear in supporting
+ * documentation, and that the name of M.I.T. not be used in
+ * advertising or publicity pertaining to distribution of the
+ * software without specific, written prior permission.
+ * M.I.T. makes no representations about the suitability of
+ * this software for any purpose.  It is provided "as is"
+ * without express or implied warranty.
+ */
+
+#include "setup.h"
+
+#include <limits.h>
+#include "ares.h"
+#include "ares_private.h"
+
+#ifndef HAVE_WRITEV
+ssize_t ares_writev(ares_socket_t s, const struct iovec *iov, int iovcnt)
+{
+  char *buffer, *bp;
+  int i;
+  size_t bytes = 0;
+  ssize_t result;
+
+  /* Validate iovcnt */
+  if (iovcnt <= 0)
+  {
+    SET_ERRNO(EINVAL);
+    return (-1);
+  }
+
+  /* Validate and find the sum of the iov_len values in the iov array */
+  for (i = 0; i < iovcnt; i++)
+  {
+    if (iov[i].iov_len > INT_MAX - bytes)
+    {
+      SET_ERRNO(EINVAL);
+      return (-1);
+    }
+    bytes += iov[i].iov_len;
+  }
+
+  if (bytes == 0)
+    return (0);
+
+  /* Allocate a temporary buffer to hold the data */
+  buffer = malloc(bytes);
+  if (!buffer)
+  {
+    SET_ERRNO(ENOMEM);
+    return (-1);
+  }
+
+  /* Copy the data into buffer */
+  for (bp = buffer, i = 0; i < iovcnt; ++i)
+  {
+    memcpy (bp, iov[i].iov_base, iov[i].iov_len);
+    bp += iov[i].iov_len;
+  }
+
+  /* Send buffer contents */
+  result = swrite(s, buffer, bytes);
+
+  free(buffer);
+
+  return (result);
+}
+#endif
+