iovec.c revision 9acbbeaf2a1ffe5c14b244867d427714fab43c5c
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
#include <errno.h>
#include <unistd.h>
#include <sys/uio.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <alloca.h>
#include <string.h>
#include <sys/lx_syscall.h>
#include <sys/lx_misc.h>
#include <sys/lx_types.h>
static int
lx_is_directory(int fd)
{
struct stat64 sbuf;
if (fstat64(fd, &sbuf) < 0)
sbuf.st_mode = 0;
return ((sbuf.st_mode & S_IFMT) == S_IFDIR);
}
int
lx_read(uintptr_t p1, uintptr_t p2, uintptr_t p3)
{
int fd = (int)p1;
void *buf = (void *)p2;
size_t nbyte = (size_t)p3;
ssize_t ret;
if (lx_is_directory(fd))
return (-EISDIR);
if ((ret = read(fd, buf, nbyte)) < 0)
return (-errno);
return (ret);
}
int
lx_pread64(uintptr_t p1, uintptr_t p2, uintptr_t p3, uintptr_t p4, uintptr_t p5)
{
int fd = (int)p1;
void *buf = (void *)p2;
size_t nbyte = (size_t)p3;
uintptr_t off_lo = p4;
uintptr_t off_hi = p5;
ssize_t ret;
if (lx_is_directory(fd))
return (-EISDIR);
ret = pread64(fd, buf, nbyte, (off64_t)LX_32TO64(off_lo, off_hi));
if (ret < 0)
return (-errno);
return (ret);
}
/*
* Implementation of Linux readv() and writev() system calls.
*
* The Linux system calls differ from the Solaris system calls in a few key
* areas:
*
* - On Solaris, the maximum number of I/O vectors that can be passed to readv()
* or writev() is IOV_MAX (16). Linux has a much larger restriction (1024).
*
* - Passing 0 as a vector count is an error on Solaris, but on Linux results
* in a return value of 0. Even though the man page says the opposite.
*
* - If the Nth vector results in an error, Solaris will return an error code
* for the entire operation. Linux only returns an error if there has been
* no data transferred yet. Otherwise, it returns the number of bytes
* transferred up until that point.
*
* In order to accomodate these differences, we implement these functions as a
* series of ordinary read() or write() calls.
*/
#define LX_IOV_MAX 1024 /* Also called MAX_IOVEC */
static int
lx_iovec_copy_and_check(const struct iovec *iovp, struct iovec *iov, int count)
{
int i;
ssize_t cnt = 0;
if (uucopy(iovp, (void *)iov, count * sizeof (struct iovec)) != 0)
return (-errno);
for (i = 0; i < count; i++) {
cnt += iov[i].iov_len;
if (iov[i].iov_len < 0 || cnt < 0)
return (-EINVAL);
}
return (0);
}
int
lx_readv(uintptr_t p1, uintptr_t p2, uintptr_t p3)
{
int fd = (int)p1;
const struct iovec *iovp = (const struct iovec *)p2;
int count = (int)p3;
struct iovec *iov;
ssize_t total = 0, ret;
int i;
if (count == 0)
return (0);
if (count < 0 || count > LX_IOV_MAX)
return (-EINVAL);
if (lx_is_directory(fd))
return (-EISDIR);
iov = SAFE_ALLOCA(count * sizeof (struct iovec));
if (iov == NULL)
return (-ENOMEM);
if ((ret = lx_iovec_copy_and_check(iovp, iov, count)) != 0)
return (ret);
for (i = 0; i < count; i++) {
ret = read(fd, iov[i].iov_base, iov[i].iov_len);
if (ret < 0) {
if (total > 0)
return (total);
return (-errno);
}
total += ret;
}
return (total);
}
int
lx_writev(uintptr_t p1, uintptr_t p2, uintptr_t p3)
{
int fd = (int)p1;
const struct iovec *iovp = (const struct iovec *)p2;
int count = (int)p3;
struct iovec *iov;
ssize_t total = 0, ret;
int i;
if (count == 0)
return (0);
if (count < 0 || count > LX_IOV_MAX)
return (-EINVAL);
iov = SAFE_ALLOCA(count * sizeof (struct iovec));
if (iov == NULL)
return (-ENOMEM);
if ((ret = lx_iovec_copy_and_check(iovp, iov, count)) != 0)
return (ret);
for (i = 0; i < count; i++) {
ret = write(fd, iov[i].iov_base, iov[i].iov_len);
if (ret < 0) {
if (total > 0)
return (total);
return (-errno);
}
total += ret;
}
return (total);
}