libcsupport/src/fchdir.c

0001 /* SPDX-License-Identifier: BSD-2-Clause */
0002
0003 /**
0004  *  @file
0005  *
0006  *  @brief Change Directory
0007  *  @ingroup libcsupport
0008  */
0009
0010 /*
0011  *  COPYRIGHT (c) 1989-2011.
0012  *  On-Line Applications Research Corporation (OAR).
0013  *
0014  *  Modifications to support reference counting in the file system are
0015  *  Copyright (c) 2012 embedded brains GmbH & Co. KG
0016  *
0017  * Redistribution and use in source and binary forms, with or without
0018  * modification, are permitted provided that the following conditions
0019  * are met:
0020  * 1. Redistributions of source code must retain the above copyright
0021  *    notice, this list of conditions and the following disclaimer.
0022  * 2. Redistributions in binary form must reproduce the above copyright
0023  *    notice, this list of conditions and the following disclaimer in the
0024  *    documentation and/or other materials provided with the distribution.
0025  *
0026  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
0027  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
0028  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
0029  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
0030  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
0031  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
0032  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
0033  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
0034  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
0035  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
0036  * POSSIBILITY OF SUCH DAMAGE.
0037  */
0038
0039 #ifdef HAVE_CONFIG_H
0040 #include "config.h"
0041 #endif
0042
0043 #include <unistd.h>
0044
0045 #include <rtems/libio_.h>
0046
0047 /**
0048  *  compatible with SVr4, 4.4BSD and X/OPEN - Change Directory
0049  */
0050 int fchdir( int fd )
0051 {
0052   int rv = 0;
0053   rtems_libio_t *iop;
0054   struct stat st;
0055   rtems_filesystem_location_info_t loc;
0056
0057   st.st_mode = 0;
0058   st.st_uid = 0;
0059   st.st_gid = 0;
0060
0061   LIBIO_GET_IOP( fd, iop );
0062
0063   rtems_filesystem_instance_lock( &iop->pathinfo );
0064   rv = (*iop->pathinfo.handlers->fstat_h)( &iop->pathinfo, &st );
0065   if ( rv == 0 ) {
0066     bool access_ok = rtems_filesystem_check_access(
0067       RTEMS_FS_PERMS_EXEC,
0068       st.st_mode,
0069       st.st_uid,
0070       st.st_gid
0071     );
0072
0073     if ( access_ok ) {
0074       rtems_filesystem_location_clone( &loc, &iop->pathinfo );
0075     } else {
0076       errno = EACCES;
0077       rv = -1;
0078     }
0079   }
0080   rtems_filesystem_instance_unlock( &iop->pathinfo );
0081   rtems_libio_iop_drop( iop );
0082
0083   if ( rv == 0 ) {
0084     rv = rtems_filesystem_chdir( &loc );
0085   }
0086
0087   return rv;
0088 }