LXR linux/include/linux/uio.h

   1/*
   2 *      Berkeley style UIO structures   -       Alan Cox 1994.
   3 *
   4 *              This program is free software; you can redistribute it and/or
   5 *              modify it under the terms of the GNU General Public License
   6 *              as published by the Free Software Foundation; either version
   7 *              2 of the License, or (at your option) any later version.
   8 */
   9#ifndef __LINUX_UIO_H
  10#define __LINUX_UIO_H
  11
  12#include <uapi/linux/uio.h>
  13
  14
  15struct kvec {
  16        void *iov_base; /* and that should *never* hold a userland pointer */
  17        size_t iov_len;
  18};
  19
  20/*
  21 * Total number of bytes covered by an iovec.
  22 *
  23 * NOTE that it is not safe to use this function until all the iovec's
  24 * segment lengths have been validated.  Because the individual lengths can
  25 * overflow a size_t when added together.
  26 */
  27static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs)
  28{
  29        unsigned long seg;
  30        size_t ret = 0;
  31
  32        for (seg = 0; seg < nr_segs; seg++)
  33                ret += iov[seg].iov_len;
  34        return ret;
  35}
  36
  37unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to);
  38
  39int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len);
  40int memcpy_toiovec(struct iovec *iov, unsigned char *kdata, int len);
  41#endif
  42