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- /****************************************************************************
- * libs/libc/misc/lib_sendfile.c
- *
- * Copyright (C) 2007, 2009, 2011, 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/sendfile.h>
- #include <stdbool.h>
- #include <stdlib.h>
- #include <unistd.h>
- #include <errno.h>
- #include <nuttx/fs/fs.h>
- #include "libc.h"
- /****************************************************************************
- * Public Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: sendfile / lib_sendfile
- *
- * Description:
- * sendfile() copies data between one file descriptor and another.
- * sendfile() basically just wraps a sequence of reads() and writes()
- * to perform a copy. It serves a purpose in systems where there is
- * a penalty for copies to between user and kernal space, but really
- * nothing in NuttX but provide some Linux compatible (and adding
- * another 'almost standard' interface).
- *
- * NOTE: This interface is *not* specified in POSIX.1-2001, or other
- * standards. The implementation here is very similar to the Linux
- * sendfile interface. Other UNIX systems implement sendfile() with
- * different semantics and prototypes. sendfile() should not be used
- * in portable programs.
- *
- * Input Parameters:
- * infd - A file (or socket) descriptor opened for reading
- * outfd - A descriptor opened for writing.
- * offset - If 'offset' is not NULL, then it points to a variable
- * holding the file offset from which sendfile() will start
- * reading data from 'infd'. When sendfile() returns, this
- * variable will be set to the offset of the byte following
- * the last byte that was read. If 'offset' is not NULL,
- * then sendfile() does not modify the current file offset of
- * 'infd'; otherwise the current file offset is adjusted to
- * reflect the number of bytes read from 'infd.'
- *
- * If 'offset' is NULL, then data will be read from 'infd'
- * starting at the current file offset, and the file offset
- * will be updated by the call.
- * count - The number of bytes to copy between the file descriptors.
- *
- * Returned Value:
- * If the transfer was successful, the number of bytes written to outfd is
- * returned. On error, -1 is returned, and errno is set appropriately.
- * There error values are those returned by read() or write() plus:
- *
- * EINVAL - Bad input parameters.
- * ENOMEM - Could not allocated an I/O buffer
- *
- ****************************************************************************/
- #ifdef CONFIG_NET_SENDFILE
- ssize_t lib_sendfile(int outfd, int infd, off_t *offset, size_t count)
- #else
- ssize_t sendfile(int outfd, int infd, off_t *offset, size_t count)
- #endif
- {
- FAR uint8_t *iobuffer;
- FAR uint8_t *wrbuffer;
- off_t startpos = 0;
- ssize_t nbytesread;
- ssize_t nbyteswritten;
- size_t ntransferred;
- bool endxfr;
- /* Get the current file position. */
- if (offset)
- {
- /* Use lseek to get the current file position */
- startpos = lseek(infd, 0, SEEK_CUR);
- if (startpos == (off_t)-1)
- {
- return ERROR;
- }
- /* Use lseek again to set the new file position */
- if (lseek(infd, *offset, SEEK_SET) == (off_t)-1)
- {
- return ERROR;
- }
- }
- /* Allocate an I/O buffer */
- iobuffer = (FAR void *)lib_malloc(CONFIG_LIB_SENDFILE_BUFSIZE);
- if (!iobuffer)
- {
- set_errno(ENOMEM);
- return ERROR;
- }
- /* Now transfer 'count' bytes from the infd to the outfd */
- for (ntransferred = 0, endxfr = false; ntransferred < count && !endxfr; )
- {
- /* Loop until the read side of the transfer comes to some conclusion */
- do
- {
- /* Read a buffer of data from the infd */
- nbytesread = _NX_READ(infd, iobuffer, CONFIG_LIB_SENDFILE_BUFSIZE);
- /* Check for end of file */
- if (nbytesread == 0)
- {
- /* End of file. Break out and return current number of bytes
- * transferred.
- */
- endxfr = true;
- break;
- }
- /* Check for a read ERROR. EINTR is a special case. This function
- * should break out and return an error if EINTR is returned and
- * no data has been transferred. But what should it do if some
- * data has been transferred? I suppose just continue?
- */
- else if (nbytesread < 0)
- {
- int errcode = _NX_GETERRNO(nbytesread);
- /* EINTR is not an error (but will still stop the copy) */
- if (errcode != EINTR || ntransferred == 0)
- {
- /* Read error. Break out and return the error condition. */
- _NX_SETERRNO(nbytesread);
- ntransferred = ERROR;
- endxfr = true;
- break;
- }
- }
- }
- while (nbytesread < 0);
- /* Was anything read? */
- if (!endxfr)
- {
- /* Yes.. Loop until the read side of the transfer comes to some
- * conclusion.
- */
- wrbuffer = iobuffer;
- do
- {
- /* Write the buffer of data to the outfd */
- nbyteswritten = _NX_WRITE(outfd, wrbuffer, nbytesread);
- /* Check for a complete (or parial) write. write() should not
- * return zero.
- */
- if (nbyteswritten >= 0)
- {
- /* Advance the buffer pointer and decrement the number of bytes
- * remaining in the iobuffer. Typically, nbytesread will now
- * be zero.
- */
- wrbuffer += nbyteswritten;
- nbytesread -= nbyteswritten;
- /* Increment the total number of bytes successfully transferred. */
- ntransferred += nbyteswritten;
- }
- /* Otherwise an error occurred */
- else
- {
- int errcode = _NX_GETERRNO(nbyteswritten);
- /* Check for a read ERROR. EINTR is a special case. This
- * function should break out and return an error if EINTR
- * is returned and no data has been transferred. But what
- * should it do if some data has been transferred? I
- * suppose just continue?
- */
- if (errcode != EINTR || ntransferred == 0)
- {
- /* Write error. Break out and return the error
- * condition.
- */
- _NX_SETERRNO(nbyteswritten);
- ntransferred = ERROR;
- endxfr = true;
- break;
- }
- }
- }
- while (nbytesread > 0);
- }
- }
- /* Release the I/O buffer */
- lib_free(iobuffer);
- /* Return the current file position */
- if (offset)
- {
- /* Use lseek to get the current file position */
- off_t curpos = lseek(infd, 0, SEEK_CUR);
- if (curpos == (off_t)-1)
- {
- return ERROR;
- }
- /* Return the current file position */
- *offset = curpos;
- /* Use lseek again to restore the original file position */
- if (lseek(infd, startpos, SEEK_SET) == (off_t)-1)
- {
- return ERROR;
- }
- }
- /* Finally return the number of bytes actually transferred (or ERROR
- * if any failure occurred).
- */
- return ntransferred;
- }
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