usr/src/lib/libfakekernel/common/uio.c

   1 /*
   2  * This file and its contents are supplied under the terms of the
   3  * Common Development and Distribution License ("CDDL"), version 1.0.
   4  * You may only use this file in accordance with the terms of version
   5  * 1.0 of the CDDL.
   6  *
   7  * A full copy of the text of the CDDL should have accompanied this
   8  * source.  A copy of the CDDL is also available via the Internet at
   9  * http://www.illumos.org/license/CDDL.
  10  */
  11
  12 /*
  13  * Copyright 2015 Nexenta Systems, Inc.  All rights reserved.
  14  */
  15
  16 #include <sys/types.h>
  17 #include <sys/sysmacros.h>
  18 #include <sys/param.h>
  19 #include <sys/systm.h>
  20 #include <sys/uio.h>
  21 #include <sys/errno.h>
  22
  23 /*
  24  * Move "n" bytes at byte address "p"; "rw" indicates the direction
  25  * of the move, and the I/O parameters are provided in "uio", which is
  26  * update to reflect the data which was moved.  Returns 0 on success or
  27  * a non-zero errno on failure.
  28  */
  29 int
  30 uiomove(void *p, size_t n, enum uio_rw rw, struct uio *uio)
  31 {
  32         struct iovec *iov;
  33         ulong_t cnt;
  34
  35         while (n && uio->uio_resid) {
  36                 iov = uio->uio_iov;
  37                 cnt = MIN(iov->iov_len, n);
  38                 if (cnt == 0L) {
  39                         uio->uio_iov++;
  40                         uio->uio_iovcnt--;
  41                         continue;
  42                 }
  43                 switch (uio->uio_segflg) {
  44
  45                 case UIO_USERSPACE:
  46                 case UIO_USERISPACE:
  47                         return (EINVAL);
  48
  49                 case UIO_SYSSPACE:
  50                         if (rw == UIO_READ)
  51                                 bcopy(p, iov->iov_base, cnt);
  52                         else
  53                                 bcopy(iov->iov_base, p, cnt);
  54                         break;
  55                 }
  56                 iov->iov_base += cnt;
  57                 iov->iov_len -= cnt;
  58                 uio->uio_resid -= cnt;
  59                 uio->uio_loffset += cnt;
  60                 p = (caddr_t)p + cnt;
  61                 n -= cnt;
  62         }
  63         return (0);
  64 }
  65
  66 /*
  67  * Drop the next n chars out of *uiop.
  68  */
  69 void
  70 uioskip(uio_t *uiop, size_t n)
  71 {
  72         if (n > uiop->uio_resid)
  73                 return;
  74         while (n != 0) {
  75                 iovec_t *iovp = uiop->uio_iov;
  76                 size_t  niovb = MIN(iovp->iov_len, n);
  77
  78                 if (niovb == 0) {
  79                         uiop->uio_iov++;
  80                         uiop->uio_iovcnt--;
  81                         continue;
  82                 }
  83                 iovp->iov_base += niovb;
  84                 uiop->uio_loffset += niovb;
  85                 iovp->iov_len -= niovb;
  86                 uiop->uio_resid -= niovb;
  87                 n -= niovb;
  88         }
  89 }