138 lines
5.3 KiB
C
138 lines
5.3 KiB
C
/****************************************************************************
|
|
* fs/procfs/fs_procfsutil.c
|
|
*
|
|
* Copyright (C) 2013 Gregory Nutt. All rights reserved.
|
|
* Author: Gregory Nutt <gnutt@nuttx.org>
|
|
*
|
|
* 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 NuttX 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 OWNER 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 <nuttx/config.h>
|
|
|
|
#include <sys/types.h>
|
|
#include <string.h>
|
|
|
|
#include <nuttx/fs/procfs.h>
|
|
|
|
#if !defined(CONFIG_DISABLE_MOUNTPOINT) && defined(CONFIG_FS_PROCFS)
|
|
|
|
/****************************************************************************
|
|
* Pre-processor Definitions
|
|
****************************************************************************/
|
|
|
|
#ifndef MIN
|
|
# define MIN(a,b) ((a < b) ? a : b)
|
|
#endif
|
|
|
|
#ifndef MAX
|
|
# define MAX(a,b) ((a > b) ? a : b)
|
|
#endif
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: procfs_memcpy
|
|
*
|
|
* Description:
|
|
* procfs/ file data may be read by the user with different user buffer
|
|
* sizes to receive the data. If the amount of data to be returned is
|
|
* large or if the callers receive buffer is small, then multiple read
|
|
* operations will be required.
|
|
*
|
|
* If multiple read operations are required, then each read operation will
|
|
* be identical accept that file position (f_pos) will be incremented with
|
|
* each read: f_pos must be incremented by the read method after each
|
|
* read operation to provide the 'offset' for the next read.
|
|
*
|
|
* procfs_memcpy() is a helper function. Each read() method should
|
|
* provide data in a local data buffer ('src' and 'srclen'). This
|
|
* will transfer the data to the user receive buffer ('dest' and 'destlen'),
|
|
* respecting both (1) the size of the destination buffer so that it will
|
|
* write beyond the user receiver and (1) the file position, 'offset'.
|
|
*
|
|
* This function will skip over data until the under of bytes specified
|
|
* by 'offset' have been skipped. Then it will transfer data from the
|
|
* the procfs/ 'src' buffer into the user receive buffer. No more than
|
|
* 'destlen' bytes will be transferred.
|
|
*
|
|
* Input Parameters:
|
|
* src - The address of the intermediate procfs/ buffer containing the
|
|
* data to be returned.
|
|
* srclen - The number of bytes of data in the 'src' buffer
|
|
* dest - The address of the user's receive buffer.
|
|
* destlen - The size (in bytes) of the user's receive buffer.
|
|
* offset - On input, this is the number of bytes to skip before returning
|
|
* data; If bytes were skipped, this offset will be decremented.
|
|
* Data will not be transferred until this offset decrements to
|
|
* zero.
|
|
*
|
|
* Returned Value:
|
|
* The number of bytes actually transferred into the user's receive buffer.
|
|
*
|
|
****************************************************************************/
|
|
|
|
size_t procfs_memcpy(FAR const char *src, size_t srclen,
|
|
FAR char *dest, size_t destlen,
|
|
off_t *offset)
|
|
{
|
|
size_t copysize;
|
|
size_t lnoffset;
|
|
|
|
/* Will this line take us past the offset? */
|
|
|
|
lnoffset = *offset;
|
|
if (srclen < lnoffset)
|
|
{
|
|
/* No... decrement the offset and return without doing anything */
|
|
|
|
*offset -= srclen;
|
|
return 0;
|
|
}
|
|
|
|
/* Handle the remaining offset */
|
|
|
|
srclen -= lnoffset;
|
|
dest += lnoffset;
|
|
*offset = 0;
|
|
|
|
/* Copy the line into the user destination buffer */
|
|
|
|
copysize = MIN(srclen, destlen);
|
|
memcpy(dest, src, copysize);
|
|
return copysize;
|
|
}
|
|
|
|
#endif /* !CONFIG_DISABLE_MOUNTPOINT && CONFIG_FS_PROCFS */
|