2 * Buffer-based memory allocator
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4 * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
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5 * SPDX-License-Identifier: Apache-2.0
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7 * Licensed under the Apache License, Version 2.0 (the "License"); you may
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8 * not use this file except in compliance with the License.
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9 * You may obtain a copy of the License at
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11 * http://www.apache.org/licenses/LICENSE-2.0
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13 * Unless required by applicable law or agreed to in writing, software
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14 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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15 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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16 * See the License for the specific language governing permissions and
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17 * limitations under the License.
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19 * This file is part of mbed TLS (https://tls.mbed.org)
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22 #if !defined(MBEDTLS_CONFIG_FILE)
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23 #include "mbedtls/config.h"
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25 #include MBEDTLS_CONFIG_FILE
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28 #if defined(MBEDTLS_MEMORY_BUFFER_ALLOC_C)
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29 #include "mbedtls/memory_buffer_alloc.h"
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31 /* No need for the header guard as MBEDTLS_MEMORY_BUFFER_ALLOC_C
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32 is dependent upon MBEDTLS_PLATFORM_C */
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33 #include "mbedtls/platform.h"
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34 #include "mbedtls/platform_util.h"
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38 #if defined(MBEDTLS_MEMORY_BACKTRACE)
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39 #include <execinfo.h>
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42 #if defined(MBEDTLS_THREADING_C)
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43 #include "mbedtls/threading.h"
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46 #define MAGIC1 0xFF00AA55
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47 #define MAGIC2 0xEE119966
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50 typedef struct _memory_header memory_header;
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51 struct _memory_header
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56 memory_header *prev;
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57 memory_header *next;
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58 memory_header *prev_free;
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59 memory_header *next_free;
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60 #if defined(MBEDTLS_MEMORY_BACKTRACE)
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71 memory_header *first;
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72 memory_header *first_free;
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74 #if defined(MBEDTLS_MEMORY_DEBUG)
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78 size_t maximum_used;
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79 size_t header_count;
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80 size_t maximum_header_count;
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82 #if defined(MBEDTLS_THREADING_C)
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83 mbedtls_threading_mutex_t mutex;
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88 static buffer_alloc_ctx heap;
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90 #if defined(MBEDTLS_MEMORY_DEBUG)
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91 static void debug_header( memory_header *hdr )
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93 #if defined(MBEDTLS_MEMORY_BACKTRACE)
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97 mbedtls_fprintf( stderr, "HDR: PTR(%10zu), PREV(%10zu), NEXT(%10zu), "
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98 "ALLOC(%zu), SIZE(%10zu)\n",
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99 (size_t) hdr, (size_t) hdr->prev, (size_t) hdr->next,
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100 hdr->alloc, hdr->size );
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101 mbedtls_fprintf( stderr, " FPREV(%10zu), FNEXT(%10zu)\n",
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102 (size_t) hdr->prev_free, (size_t) hdr->next_free );
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104 #if defined(MBEDTLS_MEMORY_BACKTRACE)
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105 mbedtls_fprintf( stderr, "TRACE: \n" );
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106 for( i = 0; i < hdr->trace_count; i++ )
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107 mbedtls_fprintf( stderr, "%s\n", hdr->trace[i] );
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108 mbedtls_fprintf( stderr, "\n" );
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112 static void debug_chain( void )
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114 memory_header *cur = heap.first;
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116 mbedtls_fprintf( stderr, "\nBlock list\n" );
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117 while( cur != NULL )
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119 debug_header( cur );
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123 mbedtls_fprintf( stderr, "Free list\n" );
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124 cur = heap.first_free;
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126 while( cur != NULL )
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128 debug_header( cur );
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129 cur = cur->next_free;
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132 #endif /* MBEDTLS_MEMORY_DEBUG */
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134 static int verify_header( memory_header *hdr )
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136 if( hdr->magic1 != MAGIC1 )
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138 #if defined(MBEDTLS_MEMORY_DEBUG)
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139 mbedtls_fprintf( stderr, "FATAL: MAGIC1 mismatch\n" );
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144 if( hdr->magic2 != MAGIC2 )
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146 #if defined(MBEDTLS_MEMORY_DEBUG)
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147 mbedtls_fprintf( stderr, "FATAL: MAGIC2 mismatch\n" );
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152 if( hdr->alloc > 1 )
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154 #if defined(MBEDTLS_MEMORY_DEBUG)
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155 mbedtls_fprintf( stderr, "FATAL: alloc has illegal value\n" );
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160 if( hdr->prev != NULL && hdr->prev == hdr->next )
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162 #if defined(MBEDTLS_MEMORY_DEBUG)
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163 mbedtls_fprintf( stderr, "FATAL: prev == next\n" );
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168 if( hdr->prev_free != NULL && hdr->prev_free == hdr->next_free )
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170 #if defined(MBEDTLS_MEMORY_DEBUG)
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171 mbedtls_fprintf( stderr, "FATAL: prev_free == next_free\n" );
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179 static int verify_chain( void )
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181 memory_header *prv = heap.first, *cur;
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183 if( prv == NULL || verify_header( prv ) != 0 )
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185 #if defined(MBEDTLS_MEMORY_DEBUG)
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186 mbedtls_fprintf( stderr, "FATAL: verification of first header "
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192 if( heap.first->prev != NULL )
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194 #if defined(MBEDTLS_MEMORY_DEBUG)
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195 mbedtls_fprintf( stderr, "FATAL: verification failed: "
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196 "first->prev != NULL\n" );
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201 cur = heap.first->next;
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203 while( cur != NULL )
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205 if( verify_header( cur ) != 0 )
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207 #if defined(MBEDTLS_MEMORY_DEBUG)
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208 mbedtls_fprintf( stderr, "FATAL: verification of header "
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214 if( cur->prev != prv )
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216 #if defined(MBEDTLS_MEMORY_DEBUG)
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217 mbedtls_fprintf( stderr, "FATAL: verification failed: "
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218 "cur->prev != prv\n" );
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230 static void *buffer_alloc_calloc( size_t n, size_t size )
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232 memory_header *new, *cur = heap.first_free;
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235 size_t original_len, len;
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236 #if defined(MBEDTLS_MEMORY_BACKTRACE)
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237 void *trace_buffer[MAX_BT];
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241 if( heap.buf == NULL || heap.first == NULL )
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244 original_len = len = n * size;
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246 if( n == 0 || size == 0 || len / n != size )
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248 else if( len > (size_t)-MBEDTLS_MEMORY_ALIGN_MULTIPLE )
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251 if( len % MBEDTLS_MEMORY_ALIGN_MULTIPLE )
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253 len -= len % MBEDTLS_MEMORY_ALIGN_MULTIPLE;
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254 len += MBEDTLS_MEMORY_ALIGN_MULTIPLE;
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257 // Find block that fits
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259 while( cur != NULL )
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261 if( cur->size >= len )
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264 cur = cur->next_free;
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270 if( cur->alloc != 0 )
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272 #if defined(MBEDTLS_MEMORY_DEBUG)
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273 mbedtls_fprintf( stderr, "FATAL: block in free_list but allocated "
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279 #if defined(MBEDTLS_MEMORY_DEBUG)
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280 heap.alloc_count++;
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283 // Found location, split block if > memory_header + 4 room left
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285 if( cur->size - len < sizeof(memory_header) +
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286 MBEDTLS_MEMORY_ALIGN_MULTIPLE )
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290 // Remove from free_list
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292 if( cur->prev_free != NULL )
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293 cur->prev_free->next_free = cur->next_free;
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295 heap.first_free = cur->next_free;
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297 if( cur->next_free != NULL )
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298 cur->next_free->prev_free = cur->prev_free;
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300 cur->prev_free = NULL;
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301 cur->next_free = NULL;
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303 #if defined(MBEDTLS_MEMORY_DEBUG)
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304 heap.total_used += cur->size;
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305 if( heap.total_used > heap.maximum_used )
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306 heap.maximum_used = heap.total_used;
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308 #if defined(MBEDTLS_MEMORY_BACKTRACE)
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309 trace_cnt = backtrace( trace_buffer, MAX_BT );
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310 cur->trace = backtrace_symbols( trace_buffer, trace_cnt );
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311 cur->trace_count = trace_cnt;
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314 if( ( heap.verify & MBEDTLS_MEMORY_VERIFY_ALLOC ) && verify_chain() != 0 )
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317 ret = (unsigned char *) cur + sizeof( memory_header );
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318 memset( ret, 0, original_len );
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323 p = ( (unsigned char *) cur ) + sizeof(memory_header) + len;
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324 new = (memory_header *) p;
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326 new->size = cur->size - len - sizeof(memory_header);
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329 new->next = cur->next;
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330 #if defined(MBEDTLS_MEMORY_BACKTRACE)
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332 new->trace_count = 0;
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334 new->magic1 = MAGIC1;
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335 new->magic2 = MAGIC2;
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337 if( new->next != NULL )
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338 new->next->prev = new;
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340 // Replace cur with new in free_list
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342 new->prev_free = cur->prev_free;
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343 new->next_free = cur->next_free;
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344 if( new->prev_free != NULL )
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345 new->prev_free->next_free = new;
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347 heap.first_free = new;
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349 if( new->next_free != NULL )
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350 new->next_free->prev_free = new;
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355 cur->prev_free = NULL;
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356 cur->next_free = NULL;
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358 #if defined(MBEDTLS_MEMORY_DEBUG)
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359 heap.header_count++;
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360 if( heap.header_count > heap.maximum_header_count )
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361 heap.maximum_header_count = heap.header_count;
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362 heap.total_used += cur->size;
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363 if( heap.total_used > heap.maximum_used )
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364 heap.maximum_used = heap.total_used;
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366 #if defined(MBEDTLS_MEMORY_BACKTRACE)
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367 trace_cnt = backtrace( trace_buffer, MAX_BT );
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368 cur->trace = backtrace_symbols( trace_buffer, trace_cnt );
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369 cur->trace_count = trace_cnt;
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372 if( ( heap.verify & MBEDTLS_MEMORY_VERIFY_ALLOC ) && verify_chain() != 0 )
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375 ret = (unsigned char *) cur + sizeof( memory_header );
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376 memset( ret, 0, original_len );
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381 static void buffer_alloc_free( void *ptr )
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383 memory_header *hdr, *old = NULL;
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384 unsigned char *p = (unsigned char *) ptr;
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386 if( ptr == NULL || heap.buf == NULL || heap.first == NULL )
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389 if( p < heap.buf || p >= heap.buf + heap.len )
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391 #if defined(MBEDTLS_MEMORY_DEBUG)
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392 mbedtls_fprintf( stderr, "FATAL: mbedtls_free() outside of managed "
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398 p -= sizeof(memory_header);
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399 hdr = (memory_header *) p;
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401 if( verify_header( hdr ) != 0 )
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404 if( hdr->alloc != 1 )
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406 #if defined(MBEDTLS_MEMORY_DEBUG)
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407 mbedtls_fprintf( stderr, "FATAL: mbedtls_free() on unallocated "
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415 #if defined(MBEDTLS_MEMORY_DEBUG)
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417 heap.total_used -= hdr->size;
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420 #if defined(MBEDTLS_MEMORY_BACKTRACE)
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421 free( hdr->trace );
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423 hdr->trace_count = 0;
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426 // Regroup with block before
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428 if( hdr->prev != NULL && hdr->prev->alloc == 0 )
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430 #if defined(MBEDTLS_MEMORY_DEBUG)
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431 heap.header_count--;
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433 hdr->prev->size += sizeof(memory_header) + hdr->size;
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434 hdr->prev->next = hdr->next;
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438 if( hdr->next != NULL )
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439 hdr->next->prev = hdr;
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441 memset( old, 0, sizeof(memory_header) );
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444 // Regroup with block after
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446 if( hdr->next != NULL && hdr->next->alloc == 0 )
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448 #if defined(MBEDTLS_MEMORY_DEBUG)
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449 heap.header_count--;
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451 hdr->size += sizeof(memory_header) + hdr->next->size;
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453 hdr->next = hdr->next->next;
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455 if( hdr->prev_free != NULL || hdr->next_free != NULL )
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457 if( hdr->prev_free != NULL )
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458 hdr->prev_free->next_free = hdr->next_free;
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460 heap.first_free = hdr->next_free;
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462 if( hdr->next_free != NULL )
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463 hdr->next_free->prev_free = hdr->prev_free;
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466 hdr->prev_free = old->prev_free;
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467 hdr->next_free = old->next_free;
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469 if( hdr->prev_free != NULL )
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470 hdr->prev_free->next_free = hdr;
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472 heap.first_free = hdr;
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474 if( hdr->next_free != NULL )
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475 hdr->next_free->prev_free = hdr;
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477 if( hdr->next != NULL )
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478 hdr->next->prev = hdr;
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480 memset( old, 0, sizeof(memory_header) );
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483 // Prepend to free_list if we have not merged
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484 // (Does not have to stay in same order as prev / next list)
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488 hdr->next_free = heap.first_free;
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489 if( heap.first_free != NULL )
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490 heap.first_free->prev_free = hdr;
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491 heap.first_free = hdr;
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494 if( ( heap.verify & MBEDTLS_MEMORY_VERIFY_FREE ) && verify_chain() != 0 )
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498 void mbedtls_memory_buffer_set_verify( int verify )
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500 heap.verify = verify;
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503 int mbedtls_memory_buffer_alloc_verify( void )
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505 return verify_chain();
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508 #if defined(MBEDTLS_MEMORY_DEBUG)
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509 void mbedtls_memory_buffer_alloc_status( void )
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511 mbedtls_fprintf( stderr,
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512 "Current use: %zu blocks / %zu bytes, max: %zu blocks / "
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513 "%zu bytes (total %zu bytes), alloc / free: %zu / %zu\n",
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514 heap.header_count, heap.total_used,
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515 heap.maximum_header_count, heap.maximum_used,
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516 heap.maximum_header_count * sizeof( memory_header )
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517 + heap.maximum_used,
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518 heap.alloc_count, heap.free_count );
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520 if( heap.first->next == NULL )
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522 mbedtls_fprintf( stderr, "All memory de-allocated in stack buffer\n" );
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526 mbedtls_fprintf( stderr, "Memory currently allocated:\n" );
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531 void mbedtls_memory_buffer_alloc_max_get( size_t *max_used, size_t *max_blocks )
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533 *max_used = heap.maximum_used;
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534 *max_blocks = heap.maximum_header_count;
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537 void mbedtls_memory_buffer_alloc_max_reset( void )
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539 heap.maximum_used = 0;
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540 heap.maximum_header_count = 0;
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543 void mbedtls_memory_buffer_alloc_cur_get( size_t *cur_used, size_t *cur_blocks )
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545 *cur_used = heap.total_used;
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546 *cur_blocks = heap.header_count;
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548 #endif /* MBEDTLS_MEMORY_DEBUG */
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550 #if defined(MBEDTLS_THREADING_C)
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551 static void *buffer_alloc_calloc_mutexed( size_t n, size_t size )
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554 if( mbedtls_mutex_lock( &heap.mutex ) != 0 )
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556 buf = buffer_alloc_calloc( n, size );
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557 if( mbedtls_mutex_unlock( &heap.mutex ) )
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562 static void buffer_alloc_free_mutexed( void *ptr )
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564 /* We have to good option here, but corrupting the heap seems
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565 * worse than loosing memory. */
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566 if( mbedtls_mutex_lock( &heap.mutex ) )
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568 buffer_alloc_free( ptr );
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569 (void) mbedtls_mutex_unlock( &heap.mutex );
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571 #endif /* MBEDTLS_THREADING_C */
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573 void mbedtls_memory_buffer_alloc_init( unsigned char *buf, size_t len )
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575 memset( &heap, 0, sizeof( buffer_alloc_ctx ) );
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577 #if defined(MBEDTLS_THREADING_C)
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578 mbedtls_mutex_init( &heap.mutex );
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579 mbedtls_platform_set_calloc_free( buffer_alloc_calloc_mutexed,
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580 buffer_alloc_free_mutexed );
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582 mbedtls_platform_set_calloc_free( buffer_alloc_calloc, buffer_alloc_free );
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585 if( len < sizeof( memory_header ) + MBEDTLS_MEMORY_ALIGN_MULTIPLE )
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587 else if( (size_t)buf % MBEDTLS_MEMORY_ALIGN_MULTIPLE )
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589 /* Adjust len first since buf is used in the computation */
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590 len -= MBEDTLS_MEMORY_ALIGN_MULTIPLE
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591 - (size_t)buf % MBEDTLS_MEMORY_ALIGN_MULTIPLE;
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592 buf += MBEDTLS_MEMORY_ALIGN_MULTIPLE
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593 - (size_t)buf % MBEDTLS_MEMORY_ALIGN_MULTIPLE;
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596 memset( buf, 0, len );
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601 heap.first = (memory_header *)buf;
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602 heap.first->size = len - sizeof( memory_header );
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603 heap.first->magic1 = MAGIC1;
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604 heap.first->magic2 = MAGIC2;
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605 heap.first_free = heap.first;
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608 void mbedtls_memory_buffer_alloc_free( void )
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610 #if defined(MBEDTLS_THREADING_C)
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611 mbedtls_mutex_free( &heap.mutex );
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613 mbedtls_platform_zeroize( &heap, sizeof(buffer_alloc_ctx) );
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616 #if defined(MBEDTLS_SELF_TEST)
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617 static int check_pointer( void *p )
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622 if( (size_t) p % MBEDTLS_MEMORY_ALIGN_MULTIPLE != 0 )
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628 static int check_all_free( void )
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631 #if defined(MBEDTLS_MEMORY_DEBUG)
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632 heap.total_used != 0 ||
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634 heap.first != heap.first_free ||
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635 (void *) heap.first != (void *) heap.buf )
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643 #define TEST_ASSERT( condition ) \
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644 if( ! (condition) ) \
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646 if( verbose != 0 ) \
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647 mbedtls_printf( "failed\n" ); \
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653 int mbedtls_memory_buffer_alloc_self_test( int verbose )
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655 unsigned char buf[1024];
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656 unsigned char *p, *q, *r, *end;
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660 mbedtls_printf( " MBA test #1 (basic alloc-free cycle): " );
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662 mbedtls_memory_buffer_alloc_init( buf, sizeof( buf ) );
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664 p = mbedtls_calloc( 1, 1 );
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665 q = mbedtls_calloc( 1, 128 );
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666 r = mbedtls_calloc( 1, 16 );
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668 TEST_ASSERT( check_pointer( p ) == 0 &&
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669 check_pointer( q ) == 0 &&
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670 check_pointer( r ) == 0 );
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676 TEST_ASSERT( check_all_free( ) == 0 );
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678 /* Memorize end to compare with the next test */
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679 end = heap.buf + heap.len;
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681 mbedtls_memory_buffer_alloc_free( );
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684 mbedtls_printf( "passed\n" );
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687 mbedtls_printf( " MBA test #2 (buf not aligned): " );
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689 mbedtls_memory_buffer_alloc_init( buf + 1, sizeof( buf ) - 1 );
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691 TEST_ASSERT( heap.buf + heap.len == end );
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693 p = mbedtls_calloc( 1, 1 );
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694 q = mbedtls_calloc( 1, 128 );
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695 r = mbedtls_calloc( 1, 16 );
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697 TEST_ASSERT( check_pointer( p ) == 0 &&
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698 check_pointer( q ) == 0 &&
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699 check_pointer( r ) == 0 );
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705 TEST_ASSERT( check_all_free( ) == 0 );
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707 mbedtls_memory_buffer_alloc_free( );
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710 mbedtls_printf( "passed\n" );
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713 mbedtls_printf( " MBA test #3 (full): " );
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715 mbedtls_memory_buffer_alloc_init( buf, sizeof( buf ) );
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717 p = mbedtls_calloc( 1, sizeof( buf ) - sizeof( memory_header ) );
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719 TEST_ASSERT( check_pointer( p ) == 0 );
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720 TEST_ASSERT( mbedtls_calloc( 1, 1 ) == NULL );
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724 p = mbedtls_calloc( 1, sizeof( buf ) - 2 * sizeof( memory_header ) - 16 );
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725 q = mbedtls_calloc( 1, 16 );
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727 TEST_ASSERT( check_pointer( p ) == 0 && check_pointer( q ) == 0 );
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728 TEST_ASSERT( mbedtls_calloc( 1, 1 ) == NULL );
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732 TEST_ASSERT( mbedtls_calloc( 1, 17 ) == NULL );
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736 TEST_ASSERT( check_all_free( ) == 0 );
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738 mbedtls_memory_buffer_alloc_free( );
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741 mbedtls_printf( "passed\n" );
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744 mbedtls_memory_buffer_alloc_free( );
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748 #endif /* MBEDTLS_SELF_TEST */
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750 #endif /* MBEDTLS_MEMORY_BUFFER_ALLOC_C */
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