libcsupport/src/fchmod.c

0001 /* SPDX-License-Identifier: BSD-2-Clause */
0002
0003 /**
0004  *  @file
0005  *
0006  *  @brief Change File Modes
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 <sys/stat.h>
0041 #include <string.h>
0042
0043 #include <rtems/libio_.h>
0044
0045 int rtems_filesystem_chmod(
0046   const rtems_filesystem_location_info_t *loc,
0047   mode_t mode
0048 )
0049 {
0050   const rtems_filesystem_mount_table_entry_t *mt_entry = loc->mt_entry;
0051   int rv;
0052
0053   if ( mt_entry->writeable || rtems_filesystem_location_is_null( loc ) ) {
0054     struct stat st;
0055
0056     memset( &st, 0, sizeof(st) );
0057
0058     rv = (*loc->handlers->fstat_h)( loc, &st );
0059     if ( rv == 0 ) {
0060       uid_t uid = geteuid();
0061
0062       if ( uid == 0 || st.st_uid == uid ) {
0063         mode_t mask = S_IRWXU | S_IRWXG | S_IRWXO | S_ISUID | S_ISGID | S_ISVTX;
0064
0065         mode = (st.st_mode & ~mask) | (mode & mask);
0066
0067         rv = (*mt_entry->ops->fchmod_h)( loc, mode );
0068       } else {
0069         errno = EPERM;
0070         rv = -1;
0071       }
0072     }
0073   } else {
0074     errno = EROFS;
0075     rv = -1;
0076   }
0077
0078   return rv;
0079 }
0080
0081 /**
0082  *  POSIX 1003.1b 5.6.4 - Change File Modes
0083  */
0084 int fchmod( int fd, mode_t mode )
0085 {
0086   int rv;
0087   rtems_libio_t *iop;
0088
0089   LIBIO_GET_IOP( fd, iop );
0090
0091   rtems_filesystem_instance_lock( &iop->pathinfo );
0092
0093   rv = rtems_filesystem_chmod( &iop->pathinfo, mode );
0094
0095   rtems_filesystem_instance_unlock( &iop->pathinfo );
0096
0097   rtems_libio_iop_drop( iop );
0098
0099   return rv;
0100 }