libcsupport/src/realloc.c

0001 /* SPDX-License-Identifier: BSD-2-Clause */
0002
0003 /**
0004  *  @file
0005  *
0006  *  @brief Reallocate Memory Block
0007  *  @ingroup libcsupport
0008  */
0009
0010 /*
0011  *  COPYRIGHT (c) 1989-2007.
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 #ifdef RTEMS_NEWLIB
0041 #include <errno.h>
0042 #include <stdlib.h>
0043 #include <string.h>
0044
0045 #include "malloc_p.h"
0046
0047 static void *new_alloc( void *old_ptr, size_t new_size, size_t old_size )
0048 {
0049   void *new_ptr;
0050
0051   /*
0052    *  There used to be a free on this error case but it is wrong to
0053    *  free the memory per OpenGroup Single UNIX Specification V2
0054    *  and the C Standard.
0055    */
0056
0057   new_ptr = malloc( new_size );
0058   if ( new_ptr == NULL ) {
0059     return NULL;
0060   }
0061
0062   memcpy( new_ptr, old_ptr, ( new_size < old_size ) ? new_size : old_size );
0063   free( old_ptr );
0064
0065   return new_ptr;
0066 }
0067
0068 void *realloc( void *ptr, size_t size )
0069 {
0070   Heap_Control       *heap;
0071   Heap_Resize_status  status;
0072   uintptr_t           old_size;
0073   uintptr_t           avail_size;
0074
0075   if ( ptr == NULL ) {
0076     return malloc( size );
0077   }
0078
0079   if ( size == 0 ) {
0080     free( ptr );
0081     return NULL;
0082   }
0083
0084   heap = RTEMS_Malloc_Heap;
0085
0086   switch ( _Malloc_System_state() ) {
0087     case MALLOC_SYSTEM_STATE_NORMAL:
0088       _RTEMS_Lock_allocator();
0089       _Malloc_Process_deferred_frees();
0090       status = _Heap_Resize_block( heap, ptr, size, &old_size, &avail_size );
0091       _RTEMS_Unlock_allocator();
0092       break;
0093     case MALLOC_SYSTEM_STATE_NO_PROTECTION:
0094       status = _Heap_Resize_block( heap, ptr, size, &old_size, &avail_size );
0095       break;
0096     default:
0097       return NULL;
0098   }
0099
0100   switch ( status ) {
0101     case HEAP_RESIZE_SUCCESSFUL:
0102       return ptr;
0103     case HEAP_RESIZE_UNSATISFIED:
0104       return new_alloc( ptr, size, old_size );
0105     default:
0106       errno = EINVAL;
0107       return NULL;
0108   }
0109 }
0110 #endif