posix/src/munmap.c

0001 /* SPDX-License-Identifier: BSD-2-Clause */
0002
0003 /*
0004  * Copyright (c) 2012 Chris Johns (chrisj@rtems.org)
0005  * Copyright (c) 2017 Gedare Bloom (gedare@rtems.org)
0006  *
0007  * Redistribution and use in source and binary forms, with or without
0008  * modification, are permitted provided that the following conditions
0009  * are met:
0010  * 1. Redistributions of source code must retain the above copyright
0011  *    notice, this list of conditions and the following disclaimer.
0012  * 2. Redistributions in binary form must reproduce the above copyright
0013  *    notice, this list of conditions and the following disclaimer in the
0014  *    documentation and/or other materials provided with the distribution.
0015  *
0016  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
0017  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
0018  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
0019  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
0020  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
0021  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
0022  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
0023  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
0024  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
0025  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
0026  * POSSIBILITY OF SUCH DAMAGE.
0027  */
0028
0029 #ifdef HAVE_CONFIG_H
0030 #include "config.h"
0031 #endif
0032
0033 #include <rtems.h>
0034 #include <errno.h>
0035 #include <stdlib.h>
0036 #include <sys/mman.h>
0037
0038 #include <rtems/posix/mmanimpl.h>
0039 #include <rtems/posix/shmimpl.h>
0040
0041 int munmap(void *addr, size_t len)
0042 {
0043   mmap_mapping     *mapping;
0044   rtems_chain_node *node;
0045
0046   /*
0047    * Clear errno.
0048    */
0049   errno = 0;
0050
0051   /*
0052    * Length cannot be 0.
0053    */
0054   if ( len == 0 ) {
0055     errno = EINVAL;
0056     return -1;
0057   }
0058
0059   /* Check for illegal addresses. Watch out for address wrap. */
0060   if (addr + len < addr) {
0061     errno = EINVAL;
0062     return -1;
0063   }
0064
0065   mmap_mappings_lock_obtain();
0066
0067   node = rtems_chain_first (&mmap_mappings);
0068   while ( !rtems_chain_is_tail( &mmap_mappings, node )) {
0069     mapping = (mmap_mapping*) node;
0070     if ( ( addr >= mapping->addr ) &&
0071          ( addr < ( mapping->addr + mapping->len )) ) {
0072       rtems_chain_extract_unprotected( node );
0073
0074       /* FIXME: generally need a way to clean-up the backing object, but
0075        * currently it only matters for MAP_SHARED shm objects. */
0076       if ( mapping->shm != NULL ) {
0077         POSIX_Shm_Attempt_delete(mapping->shm);
0078       }
0079
0080       /* only free the mapping address for non-fixed mapping */
0081       if (( mapping->flags & MAP_FIXED ) != MAP_FIXED ) {
0082         /* only free the mapping address for non-shared mapping, because we
0083          * re-use the mapping address across all of the shared mappings, and
0084          * it is memory managed independently... */
0085         if (( mapping->flags & MAP_SHARED ) != MAP_SHARED ) {
0086           free( mapping->addr );
0087         }
0088       }
0089       free( mapping );
0090       break;
0091     }
0092     node = rtems_chain_next( node );
0093   }
0094
0095   mmap_mappings_lock_release( );
0096   return 0;
0097 }