Import glibc-mainline for 2006-08-16

git-svn-id: svn://svn.eglibc.org/fsf/trunk@4 7b3dc134-2b1b-0410-93df-9e9f96275f8d

1 files changed, 101 insertions, 0 deletions

diff --git a/libc/sysdeps/posix/readv.c b/libc/sysdeps/posix/readv.c
new file mode 100644
index 000000000..f0e78e666
--- /dev/null
+++ b/libc/sysdeps/posix/readv.c
@@ -0,0 +1,101 @@
+/* Copyright (C) 1991, 1992, 1996, 1997, 2002 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, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#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>
+
+/* Read data from file descriptor FD, and put the result in the
+   buffers described by VECTOR, which is a vector of COUNT `struct iovec's.
+   The buffers are filled in the order specified.
+   Operates just like `read' (see <unistd.h>) except that data are
+   put in VECTOR instead of a contiguous buffer.  */
+ssize_t
+__libc_readv (int fd, const struct iovec *vector, int count)
+{
+  char *buffer;
+  char *buffer_start;
+  size_t bytes;
+  ssize_t bytes_read;
+  int i;
+  bool use_malloc = false;
+
+  /* Find the total number of bytes to be read.  */
+  bytes = 0;
+  for (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.  */
+  if (__libc_use_alloca (bytes))
+    buffer = (char *) __alloca (bytes);
+  else
+    {
+      buffer = (char *) malloc (bytes);
+      if (buffer == NULL)
+	/* XXX I don't know whether it is acceptable to try reading
+	   the data in chunks.  Probably not so we just fail here.  */
+	return -1;
+
+      use_malloc = true;
+    }
+
+  /* Read the data.  */
+  bytes_read = __read (fd, buffer, bytes);
+  if (bytes_read <= 0)
+    return -1;
+
+  /* Copy the data from BUFFER into the memory specified by VECTOR.  */
+  bytes = bytes_read;
+  buffer_start = buffer;
+  for (i = 0; i < count; ++i)
+    {
+      size_t copy = MIN (vector[i].iov_len, bytes);
+
+      (void) memcpy ((void *) vector[i].iov_base, (void *) buffer, copy);
+
+      buffer += copy;
+      bytes -= copy;
+      if (bytes == 0)
+	break;
+    }
+
+  if (use_malloc)
+    free (buffer_start);
+
+  return bytes_read;
+}
+#ifndef __libc_readv
+strong_alias (__libc_readv, __readv)
+weak_alias (__libc_readv, readv)
+#endif