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Diffstat (limited to 'nuttx/libc/misc/lib_sendfile.c')
| -rw-r--r-- | nuttx/libc/misc/lib_sendfile.c | 297 |
1 files changed, 297 insertions, 0 deletions
diff --git a/nuttx/libc/misc/lib_sendfile.c b/nuttx/libc/misc/lib_sendfile.c new file mode 100644 index 000000000..8a38dc317 --- /dev/null +++ b/nuttx/libc/misc/lib_sendfile.c @@ -0,0 +1,297 @@ +/************************************************************************ + * libc/misc/lib_streamsem.c + * + * Copyright (C) 2007, 2009, 2011 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> + +#if CONFIG_NSOCKET_DESCRIPTORS > 0 || CONFIG_NFILE_DESCRIPTORS > 0 + +/************************************************************************ + * Private types + ************************************************************************/ + +/************************************************************************ + * Private Variables + ************************************************************************/ + +/************************************************************************ + * Public Variables + ************************************************************************/ + +/************************************************************************ + * Private Functions + ************************************************************************/ + +/************************************************************************ + * Public Functions + ************************************************************************/ + +/************************************************************************ + * Name: 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 Parmeters: + * 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 + * + ************************************************************************/ + +ssize_t sendfile(int outfd, int infd, off_t *offset, size_t count) +{ + 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 *)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 = 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) + { + /* EINTR is not an error (but will still stop the copy) */ + +#ifndef CONFIG_DISABLE_SIGNALS + if (errno != EINTR || ntransferred == 0) +#endif + { + /* Read error. Break out and return the error condition. */ + + 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 = 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 + { + /* 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? + */ + +#ifndef CONFIG_DISABLE_SIGNALS + if (errno != EINTR || ntransferred == 0) +#endif + { + /* Write error. Break out and return the error condition */ + + ntransferred = ERROR; + endxfr = true; + break; + } + } + } + while (nbytesread > 0); + } + } + + /* Release the I/O buffer */ + + 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; +} + +#endif /* CONFIG_NSOCKET_DESCRIPTORS > 0 || CONFIG_NFILE_DESCRIPTORS > 0 */ |