memory_buffer_alloc.c

00001 /*
00002  *  Buffer-based memory allocator
00003  *
00004  *  Copyright (C) 2006-2014, Brainspark B.V.
00005  *
00006  *  This file is part of PolarSSL (http://www.polarssl.org)
00007  *  Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
00008  *
00009  *  All rights reserved.
00010  *
00011  *  This program is free software; you can redistribute it and/or modify
00012  *  it under the terms of the GNU General Public License as published by
00013  *  the Free Software Foundation; either version 2 of the License, or
00014  *  (at your option) any later version.
00015  *
00016  *  This program is distributed in the hope that it will be useful,
00017  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
00018  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00019  *  GNU General Public License for more details.
00020  *
00021  *  You should have received a copy of the GNU General Public License along
00022  *  with this program; if not, write to the Free Software Foundation, Inc.,
00023  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
00024  */
00025 
00026 #if !defined(POLARSSL_CONFIG_FILE)
00027 #include "polarssl/config.h"
00028 #else
00029 #include POLARSSL_CONFIG_FILE
00030 #endif
00031 
00032 #if defined(POLARSSL_MEMORY_BUFFER_ALLOC_C)
00033 
00034 #include "polarssl/memory_buffer_alloc.h"
00035 
00036 #include <string.h>
00037 
00038 #if defined(POLARSSL_MEMORY_DEBUG)
00039 #include <stdio.h>
00040 #if defined(POLARSSL_MEMORY_BACKTRACE)
00041 #include <execinfo.h>
00042 #endif
00043 #endif
00044 
00045 #if defined(POLARSSL_THREADING_C)
00046 #include "polarssl/threading.h"
00047 #endif
00048 
00049 #if defined(POLARSSL_PLATFORM_C)
00050 #include "polarssl/platform.h"
00051 #else
00052 #define polarssl_fprintf fprintf
00053 #endif
00054 
00055 #define MAGIC1       0xFF00AA55
00056 #define MAGIC2       0xEE119966
00057 #define MAX_BT 20
00058 
00059 typedef struct _memory_header memory_header;
00060 struct _memory_header
00061 {
00062     size_t          magic1;
00063     size_t          size;
00064     size_t          alloc;
00065     memory_header   *prev;
00066     memory_header   *next;
00067     memory_header   *prev_free;
00068     memory_header   *next_free;
00069 #if defined(POLARSSL_MEMORY_BACKTRACE)
00070     char            **trace;
00071     size_t          trace_count;
00072 #endif
00073     size_t          magic2;
00074 };
00075 
00076 typedef struct
00077 {
00078     unsigned char   *buf;
00079     size_t          len;
00080     memory_header   *first;
00081     memory_header   *first_free;
00082     size_t          current_alloc_size;
00083     int             verify;
00084 #if defined(POLARSSL_MEMORY_DEBUG)
00085     size_t          malloc_count;
00086     size_t          free_count;
00087     size_t          total_used;
00088     size_t          maximum_used;
00089     size_t          header_count;
00090     size_t          maximum_header_count;
00091 #endif
00092 #if defined(POLARSSL_THREADING_C)
00093     threading_mutex_t   mutex;
00094 #endif
00095 }
00096 buffer_alloc_ctx;
00097 
00098 static buffer_alloc_ctx heap;
00099 
00100 #if defined(POLARSSL_MEMORY_DEBUG)
00101 static void debug_header( memory_header *hdr )
00102 {
00103 #if defined(POLARSSL_MEMORY_BACKTRACE)
00104     size_t i;
00105 #endif
00106 
00107     polarssl_fprintf( stderr, "HDR:  PTR(%10u), PREV(%10u), NEXT(%10u), "
00108                               "ALLOC(%u), SIZE(%10u)\n",
00109                       (size_t) hdr, (size_t) hdr->prev, (size_t) hdr->next,
00110                       hdr->alloc, hdr->size );
00111     polarssl_fprintf( stderr, "      FPREV(%10u), FNEXT(%10u)\n",
00112                       (size_t) hdr->prev_free, (size_t) hdr->next_free );
00113 
00114 #if defined(POLARSSL_MEMORY_BACKTRACE)
00115     polarssl_fprintf( stderr, "TRACE: \n" );
00116     for( i = 0; i < hdr->trace_count; i++ )
00117         polarssl_fprintf( stderr, "%s\n", hdr->trace[i] );
00118     polarssl_fprintf( stderr, "\n" );
00119 #endif
00120 }
00121 
00122 static void debug_chain()
00123 {
00124     memory_header *cur = heap.first;
00125 
00126     polarssl_fprintf( stderr, "\nBlock list\n" );
00127     while( cur != NULL )
00128     {
00129         debug_header( cur );
00130         cur = cur->next;
00131     }
00132 
00133     polarssl_fprintf( stderr, "Free list\n" );
00134     cur = heap.first_free;
00135 
00136     while( cur != NULL )
00137     {
00138         debug_header( cur );
00139         cur = cur->next_free;
00140     }
00141 }
00142 #endif /* POLARSSL_MEMORY_DEBUG */
00143 
00144 static int verify_header( memory_header *hdr )
00145 {
00146     if( hdr->magic1 != MAGIC1 )
00147     {
00148 #if defined(POLARSSL_MEMORY_DEBUG)
00149         polarssl_fprintf( stderr, "FATAL: MAGIC1 mismatch\n" );
00150 #endif
00151         return( 1 );
00152     }
00153 
00154     if( hdr->magic2 != MAGIC2 )
00155     {
00156 #if defined(POLARSSL_MEMORY_DEBUG)
00157         polarssl_fprintf( stderr, "FATAL: MAGIC2 mismatch\n" );
00158 #endif
00159         return( 1 );
00160     }
00161 
00162     if( hdr->alloc > 1 )
00163     {
00164 #if defined(POLARSSL_MEMORY_DEBUG)
00165         polarssl_fprintf( stderr, "FATAL: alloc has illegal value\n" );
00166 #endif
00167         return( 1 );
00168     }
00169 
00170     if( hdr->prev != NULL && hdr->prev == hdr->next )
00171     {
00172 #if defined(POLARSSL_MEMORY_DEBUG)
00173         polarssl_fprintf( stderr, "FATAL: prev == next\n" );
00174 #endif
00175         return( 1 );
00176     }
00177 
00178     if( hdr->prev_free != NULL && hdr->prev_free == hdr->next_free )
00179     {
00180 #if defined(POLARSSL_MEMORY_DEBUG)
00181         polarssl_fprintf( stderr, "FATAL: prev_free == next_free\n" );
00182 #endif
00183         return( 1 );
00184     }
00185 
00186     return( 0 );
00187 }
00188 
00189 static int verify_chain()
00190 {
00191     memory_header *prv = heap.first, *cur = heap.first->next;
00192 
00193     if( verify_header( heap.first ) != 0 )
00194     {
00195 #if defined(POLARSSL_MEMORY_DEBUG)
00196         polarssl_fprintf( stderr, "FATAL: verification of first header "
00197                                   "failed\n" );
00198 #endif
00199         return( 1 );
00200     }
00201 
00202     if( heap.first->prev != NULL )
00203     {
00204 #if defined(POLARSSL_MEMORY_DEBUG)
00205         polarssl_fprintf( stderr, "FATAL: verification failed: "
00206                                   "first->prev != NULL\n" );
00207 #endif
00208         return( 1 );
00209     }
00210 
00211     while( cur != NULL )
00212     {
00213         if( verify_header( cur ) != 0 )
00214         {
00215 #if defined(POLARSSL_MEMORY_DEBUG)
00216             polarssl_fprintf( stderr, "FATAL: verification of header "
00217                                       "failed\n" );
00218 #endif
00219             return( 1 );
00220         }
00221 
00222         if( cur->prev != prv )
00223         {
00224 #if defined(POLARSSL_MEMORY_DEBUG)
00225             polarssl_fprintf( stderr, "FATAL: verification failed: "
00226                                       "cur->prev != prv\n" );
00227 #endif
00228             return( 1 );
00229         }
00230 
00231         prv = cur;
00232         cur = cur->next;
00233     }
00234 
00235     return( 0 );
00236 }
00237 
00238 static void *buffer_alloc_malloc( size_t len )
00239 {
00240     memory_header *new, *cur = heap.first_free;
00241     unsigned char *p;
00242 #if defined(POLARSSL_MEMORY_BACKTRACE)
00243     void *trace_buffer[MAX_BT];
00244     size_t trace_cnt;
00245 #endif
00246 
00247     if( heap.buf == NULL || heap.first == NULL )
00248         return( NULL );
00249 
00250     if( len % POLARSSL_MEMORY_ALIGN_MULTIPLE )
00251     {
00252         len -= len % POLARSSL_MEMORY_ALIGN_MULTIPLE;
00253         len += POLARSSL_MEMORY_ALIGN_MULTIPLE;
00254     }
00255 
00256     // Find block that fits
00257     //
00258     while( cur != NULL )
00259     {
00260         if( cur->size >= len )
00261             break;
00262 
00263         cur = cur->next_free;
00264     }
00265 
00266     if( cur == NULL )
00267         return( NULL );
00268 
00269     if( cur->alloc != 0 )
00270     {
00271 #if defined(POLARSSL_MEMORY_DEBUG)
00272         polarssl_fprintf( stderr, "FATAL: block in free_list but allocated "
00273                                   "data\n" );
00274 #endif
00275         exit( 1 );
00276     }
00277 
00278 #if defined(POLARSSL_MEMORY_DEBUG)
00279     heap.malloc_count++;
00280 #endif
00281 
00282     // Found location, split block if > memory_header + 4 room left
00283     //
00284     if( cur->size - len < sizeof(memory_header) +
00285                           POLARSSL_MEMORY_ALIGN_MULTIPLE )
00286     {
00287         cur->alloc = 1;
00288 
00289         // Remove from free_list
00290         //
00291         if( cur->prev_free != NULL )
00292             cur->prev_free->next_free = cur->next_free;
00293         else
00294             heap.first_free = cur->next_free;
00295 
00296         if( cur->next_free != NULL )
00297             cur->next_free->prev_free = cur->prev_free;
00298 
00299         cur->prev_free = NULL;
00300         cur->next_free = NULL;
00301 
00302 #if defined(POLARSSL_MEMORY_DEBUG)
00303         heap.total_used += cur->size;
00304         if( heap.total_used > heap.maximum_used)
00305             heap.maximum_used = heap.total_used;
00306 #endif
00307 #if defined(POLARSSL_MEMORY_BACKTRACE)
00308         trace_cnt = backtrace( trace_buffer, MAX_BT );
00309         cur->trace = backtrace_symbols( trace_buffer, trace_cnt );
00310         cur->trace_count = trace_cnt;
00311 #endif
00312 
00313         if( ( heap.verify & MEMORY_VERIFY_ALLOC ) && verify_chain() != 0 )
00314             exit( 1 );
00315 
00316         return ( (unsigned char *) cur ) + sizeof(memory_header);
00317     }
00318 
00319     p = ( (unsigned char *) cur ) + sizeof(memory_header) + len;
00320     new = (memory_header *) p;
00321 
00322     new->size = cur->size - len - sizeof(memory_header);
00323     new->alloc = 0;
00324     new->prev = cur;
00325     new->next = cur->next;
00326 #if defined(POLARSSL_MEMORY_BACKTRACE)
00327     new->trace = NULL;
00328     new->trace_count = 0;
00329 #endif
00330     new->magic1 = MAGIC1;
00331     new->magic2 = MAGIC2;
00332 
00333     if( new->next != NULL )
00334         new->next->prev = new;
00335 
00336     // Replace cur with new in free_list
00337     //
00338     new->prev_free = cur->prev_free;
00339     new->next_free = cur->next_free;
00340     if( new->prev_free != NULL )
00341         new->prev_free->next_free = new;
00342     else
00343         heap.first_free = new;
00344 
00345     if( new->next_free != NULL )
00346         new->next_free->prev_free = new;
00347 
00348     cur->alloc = 1;
00349     cur->size = len;
00350     cur->next = new;
00351     cur->prev_free = NULL;
00352     cur->next_free = NULL;
00353 
00354 #if defined(POLARSSL_MEMORY_DEBUG)
00355     heap.header_count++;
00356     if( heap.header_count > heap.maximum_header_count )
00357         heap.maximum_header_count = heap.header_count;
00358     heap.total_used += cur->size;
00359     if( heap.total_used > heap.maximum_used)
00360         heap.maximum_used = heap.total_used;
00361 #endif
00362 #if defined(POLARSSL_MEMORY_BACKTRACE)
00363     trace_cnt = backtrace( trace_buffer, MAX_BT );
00364     cur->trace = backtrace_symbols( trace_buffer, trace_cnt );
00365     cur->trace_count = trace_cnt;
00366 #endif
00367 
00368     if( ( heap.verify & MEMORY_VERIFY_ALLOC ) && verify_chain() != 0 )
00369         exit( 1 );
00370 
00371     return ( (unsigned char *) cur ) + sizeof(memory_header);
00372 }
00373 
00374 static void buffer_alloc_free( void *ptr )
00375 {
00376     memory_header *hdr, *old = NULL;
00377     unsigned char *p = (unsigned char *) ptr;
00378 
00379     if( ptr == NULL || heap.buf == NULL || heap.first == NULL )
00380         return;
00381 
00382     if( p < heap.buf || p > heap.buf + heap.len )
00383     {
00384 #if defined(POLARSSL_MEMORY_DEBUG)
00385         polarssl_fprintf( stderr, "FATAL: polarssl_free() outside of managed "
00386                                   "space\n" );
00387 #endif
00388         exit( 1 );
00389     }
00390 
00391     p -= sizeof(memory_header);
00392     hdr = (memory_header *) p;
00393 
00394     if( verify_header( hdr ) != 0 )
00395         exit( 1 );
00396 
00397     if( hdr->alloc != 1 )
00398     {
00399 #if defined(POLARSSL_MEMORY_DEBUG)
00400         polarssl_fprintf( stderr, "FATAL: polarssl_free() on unallocated "
00401                                   "data\n" );
00402 #endif
00403         exit( 1 );
00404     }
00405 
00406     hdr->alloc = 0;
00407 
00408 #if defined(POLARSSL_MEMORY_DEBUG)
00409     heap.free_count++;
00410     heap.total_used -= hdr->size;
00411 #endif
00412 
00413     // Regroup with block before
00414     //
00415     if( hdr->prev != NULL && hdr->prev->alloc == 0 )
00416     {
00417 #if defined(POLARSSL_MEMORY_DEBUG)
00418         heap.header_count--;
00419 #endif
00420         hdr->prev->size += sizeof(memory_header) + hdr->size;
00421         hdr->prev->next = hdr->next;
00422         old = hdr;
00423         hdr = hdr->prev;
00424 
00425         if( hdr->next != NULL )
00426             hdr->next->prev = hdr;
00427 
00428 #if defined(POLARSSL_MEMORY_BACKTRACE)
00429         free( old->trace );
00430 #endif
00431         memset( old, 0, sizeof(memory_header) );
00432     }
00433 
00434     // Regroup with block after
00435     //
00436     if( hdr->next != NULL && hdr->next->alloc == 0 )
00437     {
00438 #if defined(POLARSSL_MEMORY_DEBUG)
00439         heap.header_count--;
00440 #endif
00441         hdr->size += sizeof(memory_header) + hdr->next->size;
00442         old = hdr->next;
00443         hdr->next = hdr->next->next;
00444 
00445         if( hdr->prev_free != NULL || hdr->next_free != NULL )
00446         {
00447             if( hdr->prev_free != NULL )
00448                 hdr->prev_free->next_free = hdr->next_free;
00449             else
00450                 heap.first_free = hdr->next_free;
00451 
00452             if( hdr->next_free != NULL )
00453                 hdr->next_free->prev_free = hdr->prev_free;
00454         }
00455 
00456         hdr->prev_free = old->prev_free;
00457         hdr->next_free = old->next_free;
00458 
00459         if( hdr->prev_free != NULL )
00460             hdr->prev_free->next_free = hdr;
00461         else
00462             heap.first_free = hdr;
00463 
00464         if( hdr->next_free != NULL )
00465             hdr->next_free->prev_free = hdr;
00466 
00467         if( hdr->next != NULL )
00468             hdr->next->prev = hdr;
00469 
00470 #if defined(POLARSSL_MEMORY_BACKTRACE)
00471         free( old->trace );
00472 #endif
00473         memset( old, 0, sizeof(memory_header) );
00474     }
00475 
00476     // Prepend to free_list if we have not merged
00477     // (Does not have to stay in same order as prev / next list)
00478     //
00479     if( old == NULL )
00480     {
00481         hdr->next_free = heap.first_free;
00482         heap.first_free->prev_free = hdr;
00483         heap.first_free = hdr;
00484     }
00485 
00486 #if defined(POLARSSL_MEMORY_BACKTRACE)
00487     hdr->trace = NULL;
00488     hdr->trace_count = 0;
00489 #endif
00490 
00491     if( ( heap.verify & MEMORY_VERIFY_FREE ) && verify_chain() != 0 )
00492         exit( 1 );
00493 }
00494 
00495 void memory_buffer_set_verify( int verify )
00496 {
00497     heap.verify = verify;
00498 }
00499 
00500 int memory_buffer_alloc_verify()
00501 {
00502     return verify_chain();
00503 }
00504 
00505 #if defined(POLARSSL_MEMORY_DEBUG)
00506 void memory_buffer_alloc_status()
00507 {
00508     polarssl_fprintf( stderr,
00509                       "Current use: %u blocks / %u bytes, max: %u blocks / "
00510                       "%u bytes (total %u bytes), malloc / free: %u / %u\n",
00511                       heap.header_count, heap.total_used,
00512                       heap.maximum_header_count, heap.maximum_used,
00513                       heap.maximum_header_count * sizeof( memory_header )
00514                       + heap.maximum_used,
00515                       heap.malloc_count, heap.free_count );
00516 
00517     if( heap.first->next == NULL )
00518         polarssl_fprintf( stderr, "All memory de-allocated in stack buffer\n" );
00519     else
00520     {
00521         polarssl_fprintf( stderr, "Memory currently allocated:\n" );
00522         debug_chain();
00523     }
00524 }
00525 #endif /* POLARSSL_MEMORY_DEBUG */
00526 
00527 #if defined(POLARSSL_THREADING_C)
00528 static void *buffer_alloc_malloc_mutexed( size_t len )
00529 {
00530     void *buf;
00531     polarssl_mutex_lock( &heap.mutex );
00532     buf = buffer_alloc_malloc( len );
00533     polarssl_mutex_unlock( &heap.mutex );
00534     return( buf );
00535 }
00536 
00537 static void buffer_alloc_free_mutexed( void *ptr )
00538 {
00539     polarssl_mutex_lock( &heap.mutex );
00540     buffer_alloc_free( ptr );
00541     polarssl_mutex_unlock( &heap.mutex );
00542 }
00543 #endif /* POLARSSL_THREADING_C */
00544 
00545 int memory_buffer_alloc_init( unsigned char *buf, size_t len )
00546 {
00547     memset( &heap, 0, sizeof(buffer_alloc_ctx) );
00548     memset( buf, 0, len );
00549 
00550 #if defined(POLARSSL_THREADING_C)
00551     polarssl_mutex_init( &heap.mutex );
00552     platform_set_malloc_free( buffer_alloc_malloc_mutexed,
00553                               buffer_alloc_free_mutexed );
00554 #else
00555     platform_set_malloc_free( buffer_alloc_malloc, buffer_alloc_free );
00556 #endif
00557 
00558     heap.buf = buf;
00559     heap.len = len;
00560 
00561     heap.first = (memory_header *) buf;
00562     heap.first->size = len - sizeof(memory_header);
00563     heap.first->magic1 = MAGIC1;
00564     heap.first->magic2 = MAGIC2;
00565     heap.first_free = heap.first;
00566     return( 0 );
00567 }
00568 
00569 void memory_buffer_alloc_free()
00570 {
00571 #if defined(POLARSSL_THREADING_C)
00572     polarssl_mutex_free( &heap.mutex );
00573 #endif
00574     memset( &heap, 0, sizeof(buffer_alloc_ctx) );
00575 }
00576 
00577 #endif /* POLARSSL_MEMORY_BUFFER_ALLOC_C */
00578 
00579