mbedtls/library/memory_buffer_alloc.c

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/*
* Buffer-based memory allocator
*
* Copyright (C) 2006-2013, Brainspark B.V.
*
* This file is part of PolarSSL (http://www.polarssl.org)
* Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
*
* All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "polarssl/config.h"
#if defined(POLARSSL_MEMORY_C) && defined(POLARSSL_MEMORY_BUFFER_ALLOC_C)
#include "polarssl/memory.h"
#include <string.h>
#if defined(POLARSSL_MEMORY_DEBUG)
#include <stdio.h>
#if defined(POLARSSL_MEMORY_BACKTRACE)
#include <execinfo.h>
#endif
#endif
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#if defined(POLARSSL_THREADING_C)
#include "polarssl/threading.h"
#endif
#define MAGIC1 0xFF00AA55
#define MAGIC2 0xEE119966
#define MAX_BT 20
typedef struct _memory_header memory_header;
struct _memory_header
{
size_t magic1;
size_t size;
size_t alloc;
memory_header *prev;
memory_header *next;
memory_header *prev_free;
memory_header *next_free;
#if defined(POLARSSL_MEMORY_BACKTRACE)
char **trace;
size_t trace_count;
#endif
size_t magic2;
};
typedef struct
{
unsigned char *buf;
size_t len;
memory_header *first;
memory_header *first_free;
size_t current_alloc_size;
int verify;
#if defined(POLARSSL_MEMORY_DEBUG)
size_t malloc_count;
size_t free_count;
size_t total_used;
size_t maximum_used;
size_t header_count;
size_t maximum_header_count;
#endif
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#if defined(POLARSSL_THREADING_C)
threading_mutex_t mutex;
#endif
}
buffer_alloc_ctx;
static buffer_alloc_ctx heap;
#if defined(POLARSSL_MEMORY_DEBUG)
static void debug_header( memory_header *hdr )
{
#if defined(POLARSSL_MEMORY_BACKTRACE)
size_t i;
#endif
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fprintf( stderr, "HDR: PTR(%10u), PREV(%10u), NEXT(%10u), ALLOC(%u), SIZE(%10u)\n",
(size_t) hdr, (size_t) hdr->prev, (size_t) hdr->next,
hdr->alloc, hdr->size );
fprintf( stderr, " FPREV(%10u), FNEXT(%10u)\n",
(size_t) hdr->prev_free, (size_t) hdr->next_free );
#if defined(POLARSSL_MEMORY_BACKTRACE)
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fprintf( stderr, "TRACE: \n" );
for( i = 0; i < hdr->trace_count; i++ )
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fprintf( stderr, "%s\n", hdr->trace[i] );
fprintf( stderr, "\n" );
#endif
}
static void debug_chain()
{
memory_header *cur = heap.first;
fprintf( stderr, "\nBlock list\n" );
while( cur != NULL )
{
debug_header( cur );
cur = cur->next;
}
fprintf( stderr, "Free list\n" );
cur = heap.first_free;
while( cur != NULL )
{
debug_header( cur );
cur = cur->next_free;
}
}
#endif /* POLARSSL_MEMORY_DEBUG */
static int verify_header( memory_header *hdr )
{
if( hdr->magic1 != MAGIC1 )
{
#if defined(POLARSSL_MEMORY_DEBUG)
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fprintf( stderr, "FATAL: MAGIC1 mismatch\n" );
#endif
return( 1 );
}
if( hdr->magic2 != MAGIC2 )
{
#if defined(POLARSSL_MEMORY_DEBUG)
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fprintf( stderr, "FATAL: MAGIC2 mismatch\n" );
#endif
return( 1 );
}
if( hdr->alloc > 1 )
{
#if defined(POLARSSL_MEMORY_DEBUG)
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fprintf( stderr, "FATAL: alloc has illegal value\n" );
#endif
return( 1 );
}
if( hdr->prev != NULL && hdr->prev == hdr->next )
{
#if defined(POLARSSL_MEMORY_DEBUG)
fprintf( stderr, "FATAL: prev == next\n" );
#endif
return( 1 );
}
if( hdr->prev_free != NULL && hdr->prev_free == hdr->next_free )
{
#if defined(POLARSSL_MEMORY_DEBUG)
fprintf( stderr, "FATAL: prev_free == next_free\n" );
#endif
return( 1 );
}
return( 0 );
}
static int verify_chain()
{
memory_header *prv = heap.first, *cur = heap.first->next;
if( verify_header( heap.first ) != 0 )
{
#if defined(POLARSSL_MEMORY_DEBUG)
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fprintf( stderr, "FATAL: verification of first header failed\n" );
#endif
return( 1 );
}
if( heap.first->prev != NULL )
{
#if defined(POLARSSL_MEMORY_DEBUG)
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fprintf( stderr, "FATAL: verification failed: first->prev != NULL\n" );
#endif
return( 1 );
}
while( cur != NULL )
{
if( verify_header( cur ) != 0 )
{
#if defined(POLARSSL_MEMORY_DEBUG)
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fprintf( stderr, "FATAL: verification of header failed\n" );
#endif
return( 1 );
}
if( cur->prev != prv )
{
#if defined(POLARSSL_MEMORY_DEBUG)
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fprintf( stderr, "FATAL: verification failed: cur->prev != prv\n" );
#endif
return( 1 );
}
prv = cur;
cur = cur->next;
}
return( 0 );
}
static void *buffer_alloc_malloc( size_t len )
{
memory_header *new, *cur = heap.first_free;
unsigned char *p;
#if defined(POLARSSL_MEMORY_BACKTRACE)
void *trace_buffer[MAX_BT];
size_t trace_cnt;
#endif
if( heap.buf == NULL || heap.first == NULL )
return( NULL );
if( len % POLARSSL_MEMORY_ALIGN_MULTIPLE )
{
len -= len % POLARSSL_MEMORY_ALIGN_MULTIPLE;
len += POLARSSL_MEMORY_ALIGN_MULTIPLE;
}
// Find block that fits
//
while( cur != NULL )
{
if( cur->size >= len )
break;
cur = cur->next_free;
}
if( cur == NULL )
return( NULL );
if( cur->alloc != 0 )
{
#if defined(POLARSSL_MEMORY_DEBUG)
fprintf( stderr, "FATAL: block in free_list but allocated data\n" );
#endif
exit( 1 );
}
#if defined(POLARSSL_MEMORY_DEBUG)
heap.malloc_count++;
#endif
// Found location, split block if > memory_header + 4 room left
//
if( cur->size - len < sizeof(memory_header) + POLARSSL_MEMORY_ALIGN_MULTIPLE )
{
cur->alloc = 1;
// Remove from free_list
//
if( cur->prev_free != NULL )
cur->prev_free->next_free = cur->next_free;
else
heap.first_free = cur->next_free;
if( cur->next_free != NULL )
cur->next_free->prev_free = cur->prev_free;
cur->prev_free = NULL;
cur->next_free = NULL;
#if defined(POLARSSL_MEMORY_DEBUG)
heap.total_used += cur->size;
if( heap.total_used > heap.maximum_used)
heap.maximum_used = heap.total_used;
#endif
#if defined(POLARSSL_MEMORY_BACKTRACE)
trace_cnt = backtrace( trace_buffer, MAX_BT );
cur->trace = backtrace_symbols( trace_buffer, trace_cnt );
cur->trace_count = trace_cnt;
#endif
if( ( heap.verify & MEMORY_VERIFY_ALLOC ) && verify_chain() != 0 )
exit( 1 );
return ( (unsigned char *) cur ) + sizeof(memory_header);
}
p = ( (unsigned char *) cur ) + sizeof(memory_header) + len;
new = (memory_header *) p;
new->size = cur->size - len - sizeof(memory_header);
new->alloc = 0;
new->prev = cur;
new->next = cur->next;
#if defined(POLARSSL_MEMORY_BACKTRACE)
new->trace = NULL;
new->trace_count = 0;
#endif
new->magic1 = MAGIC1;
new->magic2 = MAGIC2;
if( new->next != NULL )
new->next->prev = new;
// Replace cur with new in free_list
//
new->prev_free = cur->prev_free;
new->next_free = cur->next_free;
if( new->prev_free != NULL )
new->prev_free->next_free = new;
else
heap.first_free = new;
if( new->next_free != NULL )
new->next_free->prev_free = new;
cur->alloc = 1;
cur->size = len;
cur->next = new;
cur->prev_free = NULL;
cur->next_free = NULL;
#if defined(POLARSSL_MEMORY_DEBUG)
heap.header_count++;
if( heap.header_count > heap.maximum_header_count )
heap.maximum_header_count = heap.header_count;
heap.total_used += cur->size;
if( heap.total_used > heap.maximum_used)
heap.maximum_used = heap.total_used;
#endif
#if defined(POLARSSL_MEMORY_BACKTRACE)
trace_cnt = backtrace( trace_buffer, MAX_BT );
cur->trace = backtrace_symbols( trace_buffer, trace_cnt );
cur->trace_count = trace_cnt;
#endif
if( ( heap.verify & MEMORY_VERIFY_ALLOC ) && verify_chain() != 0 )
exit( 1 );
return ( (unsigned char *) cur ) + sizeof(memory_header);
}
static void buffer_alloc_free( void *ptr )
{
memory_header *hdr, *old = NULL;
unsigned char *p = (unsigned char *) ptr;
if( ptr == NULL || heap.buf == NULL || heap.first == NULL )
return;
if( p < heap.buf || p > heap.buf + heap.len )
{
#if defined(POLARSSL_MEMORY_DEBUG)
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fprintf( stderr, "FATAL: polarssl_free() outside of managed space\n" );
#endif
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exit( 1 );
}
p -= sizeof(memory_header);
hdr = (memory_header *) p;
if( verify_header( hdr ) != 0 )
exit( 1 );
if( hdr->alloc != 1 )
{
#if defined(POLARSSL_MEMORY_DEBUG)
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fprintf( stderr, "FATAL: polarssl_free() on unallocated data\n" );
#endif
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exit( 1 );
}
hdr->alloc = 0;
#if defined(POLARSSL_MEMORY_DEBUG)
heap.free_count++;
heap.total_used -= hdr->size;
#endif
// Regroup with block before
//
if( hdr->prev != NULL && hdr->prev->alloc == 0 )
{
#if defined(POLARSSL_MEMORY_DEBUG)
heap.header_count--;
#endif
hdr->prev->size += sizeof(memory_header) + hdr->size;
hdr->prev->next = hdr->next;
old = hdr;
hdr = hdr->prev;
if( hdr->next != NULL )
hdr->next->prev = hdr;
#if defined(POLARSSL_MEMORY_BACKTRACE)
free( old->trace );
#endif
memset( old, 0, sizeof(memory_header) );
}
// Regroup with block after
//
if( hdr->next != NULL && hdr->next->alloc == 0 )
{
#if defined(POLARSSL_MEMORY_DEBUG)
heap.header_count--;
#endif
hdr->size += sizeof(memory_header) + hdr->next->size;
old = hdr->next;
hdr->next = hdr->next->next;
if( hdr->prev_free != NULL || hdr->next_free != NULL )
{
if( hdr->prev_free != NULL )
hdr->prev_free->next_free = hdr->next_free;
else
heap.first_free = hdr->next_free;
if( hdr->next_free != NULL )
hdr->next_free->prev_free = hdr->prev_free;
}
hdr->prev_free = old->prev_free;
hdr->next_free = old->next_free;
if( hdr->prev_free != NULL )
hdr->prev_free->next_free = hdr;
else
heap.first_free = hdr;
if( hdr->next_free != NULL )
hdr->next_free->prev_free = hdr;
if( hdr->next != NULL )
hdr->next->prev = hdr;
#if defined(POLARSSL_MEMORY_BACKTRACE)
free( old->trace );
#endif
memset( old, 0, sizeof(memory_header) );
}
// Prepend to free_list if we have not merged
// (Does not have to stay in same order as prev / next list)
//
if( old == NULL )
{
hdr->next_free = heap.first_free;
heap.first_free->prev_free = hdr;
heap.first_free = hdr;
}
#if defined(POLARSSL_MEMORY_BACKTRACE)
hdr->trace = NULL;
hdr->trace_count = 0;
#endif
if( ( heap.verify & MEMORY_VERIFY_FREE ) && verify_chain() != 0 )
exit( 1 );
}
void memory_buffer_set_verify( int verify )
{
heap.verify = verify;
}
int memory_buffer_alloc_verify()
{
return verify_chain();
}
#if defined(POLARSSL_MEMORY_DEBUG)
void memory_buffer_alloc_status()
{
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fprintf( stderr,
"Current use: %u blocks / %u bytes, max: %u blocks / %u bytes (total %u bytes), malloc / free: %u / %u\n",
heap.header_count, heap.total_used,
heap.maximum_header_count, heap.maximum_used,
heap.maximum_header_count * sizeof( memory_header )
+ heap.maximum_used,
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heap.malloc_count, heap.free_count );
if( heap.first->next == NULL )
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fprintf( stderr, "All memory de-allocated in stack buffer\n" );
else
{
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fprintf( stderr, "Memory currently allocated:\n" );
debug_chain();
}
}
#endif /* POLARSSL_MEMORY_BUFFER_ALLOC_DEBUG */
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#if defined(POLARSSL_THREADING_C)
static void *buffer_alloc_malloc_mutexed( size_t len )
{
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void *buf;
polarssl_mutex_lock( &heap.mutex );
buf = buffer_alloc_malloc( len );
polarssl_mutex_unlock( &heap.mutex );
return( buf );
}
static void buffer_alloc_free_mutexed( void *ptr )
{
polarssl_mutex_lock( &heap.mutex );
buffer_alloc_free( ptr );
polarssl_mutex_unlock( &heap.mutex );
}
#endif
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int memory_buffer_alloc_init( unsigned char *buf, size_t len )
{
memset( &heap, 0, sizeof(buffer_alloc_ctx) );
memset( buf, 0, len );
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#if defined(POLARSSL_THREADING_C)
polarssl_mutex_init( &heap.mutex );
polarssl_malloc = buffer_alloc_malloc_mutexed;
polarssl_free = buffer_alloc_free_mutexed;
#else
polarssl_malloc = buffer_alloc_malloc;
polarssl_free = buffer_alloc_free;
#endif
heap.buf = buf;
heap.len = len;
heap.first = (memory_header *) buf;
heap.first->size = len - sizeof(memory_header);
heap.first->magic1 = MAGIC1;
heap.first->magic2 = MAGIC2;
heap.first_free = heap.first;
return( 0 );
}
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void memory_buffer_alloc_free()
{
#if defined(POLARSSL_THREADING_C)
polarssl_mutex_free( &heap.mutex );
#endif
memset( &heap, 0, sizeof(buffer_alloc_ctx) );
}
#endif /* POLARSSL_MEMORY_C && POLARSSL_MEMORY_BUFFER_ALLOC_C */