Prepare for radical source tree reorganization. zack/build-layout-experiment

All top-level files and directories are moved into a temporary storage
directory, REORG.TODO, except for files that will certainly still
exist in their current form at top level when we're done (COPYING,
COPYING.LIB, LICENSES, NEWS, README), all old ChangeLog files (which
are moved to the new directory OldChangeLogs, instead), and the
generated file INSTALL (which is just deleted; in the new order, there
will be no generated files checked into version control).

1 files changed, 91 insertions, 0 deletions

diff --git a/REORG.TODO/sysdeps/posix/writev.c b/REORG.TODO/sysdeps/posix/writev.c
new file mode 100644
index 0000000000..7ce1deb80f
--- /dev/null
+++ b/REORG.TODO/sysdeps/posix/writev.c
@@ -0,0 +1,91 @@
+/* Copyright (C) 1991-2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <limits.h>
+#include <stdbool.h>
+#include <sys/param.h>
+#include <sys/uio.h>
+#include <errno.h>
+
+
+static void
+ifree (char **ptrp)
+{
+  free (*ptrp);
+}
+
+
+/* Write data pointed by the buffers described by VECTOR, which
+   is a vector of COUNT 'struct iovec's, to file descriptor FD.
+   The data is written in the order specified.
+   Operates just like 'write' (see <unistd.h>) except that the data
+   are taken from VECTOR instead of a contiguous buffer.  */
+ssize_t
+__writev (int fd, const struct iovec *vector, int count)
+{
+  /* Find the total number of bytes to be written.  */
+  size_t bytes = 0;
+  for (int i = 0; i < count; ++i)
+    {
+      /* Check for ssize_t overflow.  */
+      if (SSIZE_MAX - bytes < vector[i].iov_len)
+	{
+	  __set_errno (EINVAL);
+	  return -1;
+	}
+      bytes += vector[i].iov_len;
+    }
+
+  /* Allocate a temporary buffer to hold the data.  We should normally
+     use alloca since it's faster and does not require synchronization
+     with other threads.  But we cannot if the amount of memory
+     required is too large.  */
+  char *buffer;
+  char *malloced_buffer __attribute__ ((__cleanup__ (ifree))) = NULL;
+  if (__libc_use_alloca (bytes))
+    buffer = (char *) __alloca (bytes);
+  else
+    {
+      malloced_buffer = buffer = (char *) malloc (bytes);
+      if (buffer == NULL)
+	/* XXX I don't know whether it is acceptable to try writing
+	   the data in chunks.  Probably not so we just fail here.  */
+	return -1;
+    }
+
+  /* Copy the data into BUFFER.  */
+  size_t to_copy = bytes;
+  char *bp = buffer;
+  for (int i = 0; i < count; ++i)
+    {
+      size_t copy = MIN (vector[i].iov_len, to_copy);
+
+      bp = __mempcpy ((void *) bp, (void *) vector[i].iov_base, copy);
+
+      to_copy -= copy;
+      if (to_copy == 0)
+	break;
+    }
+
+  ssize_t bytes_written = __write (fd, buffer, bytes);
+
+  return bytes_written;
+}
+weak_alias (__writev, writev)