27dca4d857
首先，POSIX规范规定文件描述符需要支持close-on-exec属性，修改前的vfs不支持close-on-exec，当exec系列函数执行时，进程所有的文件将会被关闭（0，1，2也重新被打开）。但是，系统有些时候是不能在exec时关闭全部文件的，例如在执行exec之前，就需要重定向进程的某些文件描述符时（使用dup2），就希望该文件不被关闭，继续保持重定向属性，shell执行进程并重定向其标准输出到文件，这是我们经常做的事情。 BREAKING CHANGE: 执行exec类函数后，进程拥有的文件描述符情况发生变化：修改前，默认关闭所有的进程文件描述符，0，1，2重新打开；修改后，除非文件描述符拥有FD_CLOEXEC标记，否则该描述符不会被关闭。 re #I3U81W Change-Id: I54e841ac88e9835ec23e97de0cbc906c4e11f5a4 Signed-off-by: Guangyao Ma <guangyao.ma@outlook.com>
51 lines
2.3 KiB
C
51 lines
2.3 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.
|
|
*/
|
|
|
|
/****************************************************************************
|
|
* Included Files
|
|
****************************************************************************/
|
|
|
|
#include "sys/types.h"
|
|
#include "sys/uio.h"
|
|
|
|
/****************************************************************************
|
|
* Private Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
ssize_t preadv(int fd, const struct iovec *iov, int iovcnt, off_t offset)
|
|
{
|
|
return vfs_readv(fd, iov, iovcnt, &offset);
|
|
}
|