nuttx/fs/vfs/fs_dupfd.c
liuhaitao bf06776f7c fs/vfs: reuse file_dup2 directly in file_dup to fix segfault issue
Or close the fd2 return by dup() would segment fault since filep->f_priv
null access.

Change-Id: I285c86f54bbb486d6c2c5aea53952f69083dca72
Signed-off-by: liuhaitao <liuhaitao@xiaomi.com>
2020-09-09 07:49:40 -07:00

128 lines
3.5 KiB
C

/****************************************************************************
* fs/vfs/fs_dupfd.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sched.h>
#include <errno.h>
#include <assert.h>
#include <nuttx/fs/fs.h>
#include "inode/inode.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#define DUP_ISOPEN(filep) (filep->f_inode != NULL)
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: file_dup
*
* Description:
* Equivalent to the non-standard fs_dupfd() function except that it
* accepts a struct file instance instead of a file descriptor.
*
* Returned Value:
* The new file descriptor is returned on success; a negated errno value
* is returned on any failure.
*
****************************************************************************/
int file_dup(FAR struct file *filep, int minfd)
{
FAR struct file *filep2;
int fd2;
int ret;
/* Verify that fd is a valid, open file descriptor */
if (!DUP_ISOPEN(filep))
{
return -EBADF;
}
/* Then allocate a new file descriptor for the inode */
fd2 = files_allocate(NULL, 0, 0, minfd);
if (fd2 < 0)
{
return -EMFILE;
}
ret = fs_getfilep(fd2, &filep2);
if (ret < 0)
{
files_release(fd2);
return ret;
}
ret = file_dup2(filep, filep2);
if (ret < 0)
{
files_release(fd2);
return ret;
}
return fd2;
}
/****************************************************************************
* Name: fs_dupfd
*
* Description:
* Clone a file descriptor 'fd' to an arbitrary descriptor number (any
* value greater than or equal to 'minfd').
*
* Returned Value:
* The new file descriptor is returned on success; a negated errno value
* is returned on any failure.
*
****************************************************************************/
int fs_dupfd(int fd, int minfd)
{
FAR struct file *filep;
int ret;
/* Get the file structure corresponding to the file descriptor. */
ret = fs_getfilep(fd, &filep);
if (ret < 0)
{
return ret;
}
DEBUGASSERT(filep != NULL);
/* Let file_dup() do the real work */
return file_dup(filep, minfd);
}