kernel_liteos_a/fs/vfs/operation/fs_writev.c

140 lines
4.2 KiB
C

/*
* Copyright (c) 2013-2019 Huawei Technologies Co., Ltd. All rights reserved.
* Copyright (c) 2020-2021 Huawei Device Co., Ltd. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this list of
* conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice, this list
* of conditions and the following disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* 3. Neither the name of the copyright holder nor the names of its contributors may be used
* to endorse or promote products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "sys/types.h"
#include "sys/uio.h"
#include "unistd.h"
#include "string.h"
#include "stdlib.h"
#include "fs/file.h"
#include "user_copy.h"
#include "limits.h"
static int iov_trans_to_buf(char *buf, ssize_t totallen, const struct iovec *iov, int iovcnt)
{
int i;
size_t ret, writepart;
size_t bytestowrite;
char *writebuf = NULL;
char *curbuf = buf;
for (i = 0; i < iovcnt; ++i) {
writebuf = (char *)iov[i].iov_base;
bytestowrite = iov[i].iov_len;
if (bytestowrite == 0) {
continue;
}
if (totallen == 0) {
break;
}
bytestowrite = (totallen < bytestowrite) ? totallen : bytestowrite;
ret = LOS_CopyToKernel(curbuf, bytestowrite, writebuf, bytestowrite);
if (ret != 0) {
if (ret == bytestowrite) {
set_errno(EFAULT);
return VFS_ERROR;
} else {
writepart = bytestowrite - ret;
curbuf += writepart;
totallen -= writepart;
break;
}
}
curbuf += bytestowrite;
totallen -= bytestowrite;
}
return (int)((intptr_t)curbuf - (intptr_t)buf);
}
ssize_t vfs_writev(int fd, const struct iovec *iov, int iovcnt, off_t *offset)
{
int i, ret;
char *buf = NULL;
size_t buflen = 0;
size_t bytestowrite;
ssize_t totalbyteswritten;
size_t totallen;
if ((iov == NULL) || (iovcnt > IOV_MAX)) {
return VFS_ERROR;
}
for (i = 0; i < iovcnt; ++i) {
if (SSIZE_MAX - buflen < iov[i].iov_len) {
set_errno(EINVAL);
return VFS_ERROR;
}
buflen += iov[i].iov_len;
}
if (buflen == 0) {
return 0;
}
totallen = buflen * sizeof(char);
#ifdef LOSCFG_KERNEL_VM
buf = (char *)LOS_VMalloc(totallen);
#else
buf = (char *)malloc(totallen);
#endif
if (buf == NULL) {
return VFS_ERROR;
}
ret = iov_trans_to_buf(buf, totallen, iov, iovcnt);
if (ret <= 0) {
#ifdef LOSCFG_KERNEL_VM
LOS_VFree(buf);
#else
free(buf);
#endif
return VFS_ERROR;
}
bytestowrite = (ssize_t)ret;
totalbyteswritten = (offset == NULL) ? write(fd, buf, bytestowrite)
: pwrite(fd, buf, bytestowrite, *offset);
#ifdef LOSCFG_KERNEL_VM
LOS_VFree(buf);
#else
free(buf);
#endif
return totalbyteswritten;
}
ssize_t writev(int fd, const struct iovec *iov, int iovcnt)
{
return vfs_writev(fd, iov, iovcnt, NULL);
}