360 lines
11 KiB
C
360 lines
11 KiB
C
/****************************************************************************
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* fs/vfs/fs_sendfile.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <sys/sendfile.h>
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#include <stdbool.h>
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#include <errno.h>
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#include <debug.h>
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#include <nuttx/kmalloc.h>
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#include <nuttx/net/net.h>
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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static ssize_t copyfile(FAR struct file *outfile, FAR struct file *infile,
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FAR off_t *offset, size_t count)
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{
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FAR uint8_t *iobuffer;
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FAR uint8_t *wrbuffer;
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off_t startpos = 0;
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ssize_t nbytesread;
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ssize_t nbyteswritten;
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size_t ntransferred;
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bool endxfr;
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/* Get the current file position. */
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if (offset)
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{
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off_t newpos;
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/* Use file_seek to get the current file position */
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startpos = file_seek(infile, 0, SEEK_CUR);
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if (startpos < 0)
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{
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return startpos;
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}
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/* Use file_seek again to set the new file position */
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newpos = file_seek(infile, *offset, SEEK_SET);
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if (newpos < 0)
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{
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return newpos;
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}
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}
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/* Allocate an I/O buffer */
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iobuffer = kmm_malloc(CONFIG_SENDFILE_BUFSIZE);
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if (!iobuffer)
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{
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return -ENOMEM;
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}
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/* Now transfer 'count' bytes from the infile to the outfile */
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for (ntransferred = 0, endxfr = false; ntransferred < count && !endxfr; )
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{
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/* Loop until the read side of the transfer comes to some conclusion */
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do
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{
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/* Read a buffer of data from the infile */
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nbytesread = count - ntransferred;
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if (nbytesread > CONFIG_SENDFILE_BUFSIZE)
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{
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nbytesread = CONFIG_SENDFILE_BUFSIZE;
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}
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nbytesread = file_read(infile, iobuffer, nbytesread);
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/* Check for end of file */
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if (nbytesread == 0)
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{
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/* End of file. Break out and return current number of bytes
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* transferred.
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*/
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endxfr = true;
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break;
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}
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/* Check for a read ERROR. EINTR is a special case. This function
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* should break out and return an error if EINTR is returned and
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* no data has been transferred. But what should it do if some
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* data has been transferred? I suppose just continue?
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*/
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else if (nbytesread < 0)
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{
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/* EINTR is not an error (but will still stop the copy) */
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if (nbytesread != -EINTR || ntransferred == 0)
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{
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/* Read error. Break out and return the error condition. */
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ntransferred = nbytesread;
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endxfr = true;
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break;
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}
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}
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}
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while (nbytesread < 0);
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/* Was anything read? */
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if (!endxfr)
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{
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/* Yes.. Loop until the read side of the transfer comes to some
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* conclusion.
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*/
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wrbuffer = iobuffer;
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do
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{
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/* Write the buffer of data to the outfile */
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nbyteswritten = file_write(outfile, wrbuffer, nbytesread);
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/* Check for a complete (or partial) write. write() should not
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* return zero.
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*/
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if (nbyteswritten >= 0)
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{
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/* Advance the buffer pointer and decrement the number of
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* bytes remaining in the iobuffer. Typically, nbytesread
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* will now be zero.
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*/
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wrbuffer += nbyteswritten;
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nbytesread -= nbyteswritten;
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/* Increment the total number of bytes successfully
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* transferred.
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*/
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ntransferred += nbyteswritten;
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}
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/* Otherwise an error occurred */
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else
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{
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/* Check for a write ERROR. EINTR is a special case. This
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* function should break out and return an error if EINTR
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* is returned and no data has been transferred. But what
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* should it do if some data has been transferred? I
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* suppose just continue?
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*/
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if (nbyteswritten != -EINTR || ntransferred == 0)
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{
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/* Write error. Break out and return the error
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* condition.
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*/
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ntransferred = nbyteswritten;
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endxfr = true;
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break;
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}
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}
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}
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while (nbytesread > 0);
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}
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}
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/* Release the I/O buffer */
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kmm_free(iobuffer);
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/* Return the current file position */
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if (offset)
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{
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/* Use file_seek to get the current file position */
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off_t curpos = file_seek(infile, 0, SEEK_CUR);
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if (curpos < 0)
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{
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return curpos;
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}
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/* Return the current file position */
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*offset = curpos;
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/* Use file_seek again to restore the original file position */
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startpos = file_seek(infile, startpos, SEEK_SET);
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if (startpos < 0)
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{
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return startpos;
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}
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}
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/* Finally return the number of bytes actually transferred (or ERROR
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* if any failure occurred).
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*/
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return ntransferred;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: file_sendfile
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*
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* Description:
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* Equivalent to the standard sendfile function except that is accepts a
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* struct file instance instead of a file descriptor.
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*
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****************************************************************************/
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ssize_t file_sendfile(FAR struct file *outfile, FAR struct file *infile,
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FAR off_t *offset, size_t count)
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{
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if (count == 0)
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{
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nwarn("WARNING: sendfile count is zero\n");
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return 0;
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}
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#ifdef CONFIG_NET_SENDFILE
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/* Check the destination file descriptor: Is it a (probable) file
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* descriptor? Check the source file: Is it a normal file?
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*/
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FAR struct socket *psock;
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psock = file_socket(outfile);
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if (psock != NULL)
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{
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/* Then let psock_sendfile do the work. */
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int ret = psock_sendfile(psock, infile, offset, count);
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if (ret >= 0 || ret != -ENOSYS)
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{
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return ret;
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}
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/* Fall back to the slow path if errno equals ENOSYS,
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* because psock_sendfile fail to optimize this transfer.
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*/
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}
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#endif
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/* No... then this is probably a file-to-file transfer. The generic
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* copyfile() can handle that case.
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*/
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return copyfile(outfile, infile, offset, count);
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}
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/****************************************************************************
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* Name: sendfile
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*
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* Description:
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* sendfile() copies data between one file descriptor and another.
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* Used with file descriptors it basically just wraps a sequence of
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* reads() and writes() to perform a copy.
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*
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* If the destination descriptor is a socket, it gives a better
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* performance than simple reds() and writes(). The data is read directly
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* into the net buffer and the whole tcp window is filled if possible.
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*
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* NOTE: This interface is *not* specified in POSIX.1-2001, or other
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* standards. The implementation here is very similar to the Linux
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* sendfile interface. Other UNIX systems implement sendfile() with
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* different semantics and prototypes. sendfile() should not be used
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* in portable programs.
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*
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* Input Parameters:
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* infd - A file (or socket) descriptor opened for reading
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* outfd - A descriptor opened for writing.
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* offset - If 'offset' is not NULL, then it points to a variable
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* holding the file offset from which sendfile() will start
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* reading data from 'infd'. When sendfile() returns, this
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* variable will be set to the offset of the byte following
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* the last byte that was read. If 'offset' is not NULL,
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* then sendfile() does not modify the current file offset of
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* 'infd'; otherwise the current file offset is adjusted to
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* reflect the number of bytes read from 'infd.'
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*
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* If 'offset' is NULL, then data will be read from 'infd'
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* starting at the current file offset, and the file offset
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* will be updated by the call.
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* count - The number of bytes to copy between the file descriptors.
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*
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* Returned Value:
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* If the transfer was successful, the number of bytes written to outfd is
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* returned. On error, -1 is returned, and errno is set appropriately.
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* There error values are those returned by read() or write() plus:
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*
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* EINVAL - Bad input parameters.
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* ENOMEM - Could not allocated an I/O buffer
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*
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****************************************************************************/
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ssize_t sendfile(int outfd, int infd, FAR off_t *offset, size_t count)
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{
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FAR struct file *outfile;
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FAR struct file *infile;
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int ret;
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ret = fs_getfilep(outfd, &outfile);
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if (ret < 0)
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{
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goto errout;
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}
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ret = fs_getfilep(infd, &infile);
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if (ret < 0)
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{
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goto errout;
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}
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ret = file_sendfile(outfile, infile, offset, count);
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if (ret < 0)
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{
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goto errout;
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}
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return ret;
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errout:
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set_errno(-ret);
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return ERROR;
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}
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