libcsupport/src/read.c

0001 /* SPDX-License-Identifier: BSD-2-Clause */
0002
0003 /**
0004  *  @file
0005  *
0006  *  @brief Read From a File
0007  *  @ingroup libcsupport
0008  */
0009
0010 /*
0011  *  COPYRIGHT (c) 1989-2011.
0012  *  On-Line Applications Research Corporation (OAR).
0013  *
0014  * Redistribution and use in source and binary forms, with or without
0015  * modification, are permitted provided that the following conditions
0016  * are met:
0017  * 1. Redistributions of source code must retain the above copyright
0018  *    notice, this list of conditions and the following disclaimer.
0019  * 2. Redistributions in binary form must reproduce the above copyright
0020  *    notice, this list of conditions and the following disclaimer in the
0021  *    documentation and/or other materials provided with the distribution.
0022  *
0023  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
0024  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
0025  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
0026  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
0027  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
0028  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
0029  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
0030  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
0031  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
0032  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
0033  * POSSIBILITY OF SUCH DAMAGE.
0034  */
0035
0036 #ifdef HAVE_CONFIG_H
0037 #include "config.h"
0038 #endif
0039
0040 #include <rtems/libio_.h>
0041 #include <rtems/seterr.h>
0042
0043 /**
0044  *  POSIX 1003.1b 6.4.1 - Read From a File
0045  */
0046 ssize_t read(
0047   int         fd,
0048   void       *buffer,
0049   size_t      count
0050 )
0051 {
0052   rtems_libio_t *iop;
0053   ssize_t        n;
0054
0055   rtems_libio_check_buffer( buffer );
0056   rtems_libio_check_count( count );
0057
0058   LIBIO_GET_IOP_WITH_ACCESS( fd, iop, LIBIO_FLAGS_READ, EBADF );
0059
0060   /*
0061    *  Now process the read().
0062    */
0063   n = (*iop->pathinfo.handlers->read_h)( iop, buffer, count );
0064   rtems_libio_iop_drop( iop );
0065   return n;
0066 }
0067
0068 #if defined(RTEMS_NEWLIB) && !defined(HAVE__READ_R)
0069
0070 #include <reent.h>
0071
0072 /**
0073  *  This is the Newlib dependent reentrant version of read().
0074  */
0075 ssize_t _read_r(
0076   struct _reent *ptr RTEMS_UNUSED,
0077   int            fd,
0078   void          *buf,
0079   size_t         nbytes
0080 )
0081 {
0082   return read( fd, buf, nbytes );
0083 }
0084 #endif