Botan::MemoryMapping_Allocator Class Reference

#include <mmap_mem.h>

Inheritance diagram for Botan::MemoryMapping_Allocator:

Public Member Functions
void *	allocate (size_t)
void	deallocate (void *, size_t)
void	destroy ()
virtual void	init ()
	MemoryMapping_Allocator (Mutex *mutex)
std::string	type () const

Static Public Member Functions
static Allocator *	get (bool locking)

Detailed Description

Allocator that uses memory maps backed by disk. We zeroize the map upon deallocation. If swap occurs, the VM will swap to the shared file backing rather than to a swap device, which means we know where it is and can zap it later.

Definition at line 21 of file mmap_mem.h.

Constructor & Destructor Documentation

MemoryMapping_Allocator()

Botan::MemoryMapping_Allocator::MemoryMapping_Allocator ( Mutex * mutex )

inline

Parameters

mutex

used for internal locking

Definition at line 27 of file mmap_mem.h.

: Pooling_Allocator(mutex) {}

References Botan::Pooling_Allocator::Pooling_Allocator().

Referenced by Botan::Library_State::initialize().

Member Function Documentation

allocate()

void * Botan::Pooling_Allocator::allocate ( size_t n )

virtualinherited

Allocate a block of memory

Parameters

n	how many bytes to allocate

Returns

pointer to n bytes of memory

Implements Botan::Allocator.

Definition at line 133 of file mem_pool.cpp.

   {
   const size_t BITMAP_SIZE = Memory_Block::bitmap_size();
   const size_t BLOCK_SIZE = Memory_Block::block_size();
 
   Mutex_Holder lock(mutex);
 
   if(n <= BITMAP_SIZE * BLOCK_SIZE)
      {
      const size_t block_no = round_up(n, BLOCK_SIZE) / BLOCK_SIZE;
 
      byte* mem = allocate_blocks(block_no);
      if(mem)
         return mem;
 
      get_more_core(BOTAN_MEM_POOL_CHUNK_SIZE);
 
      mem = allocate_blocks(block_no);
      if(mem)
         return mem;
 
      throw Memory_Exhaustion();
      }
 
   void* new_buf = alloc_block(n);
   if(new_buf)
      return new_buf;
 
   throw Memory_Exhaustion();
   }

References Botan::round_up().

deallocate()

void Botan::Pooling_Allocator::deallocate ( void * ptr, size_t n )

virtualinherited

Deallocate memory allocated with allocate()

Parameters

ptr	the pointer returned by allocate()
n	the size of the block pointed to by ptr

Implements Botan::Allocator.

Definition at line 167 of file mem_pool.cpp.

   {
   const size_t BITMAP_SIZE = Memory_Block::bitmap_size();
   const size_t BLOCK_SIZE = Memory_Block::block_size();
 
   if(ptr == 0 || n == 0)
      return;
 
   Mutex_Holder lock(mutex);
 
   if(n > BITMAP_SIZE * BLOCK_SIZE)
      dealloc_block(ptr, n);
   else
      {
      const size_t block_no = round_up(n, BLOCK_SIZE) / BLOCK_SIZE;
 
      std::vector<Memory_Block>::iterator i =
         std::lower_bound(blocks.begin(), blocks.end(), Memory_Block(ptr));
 
      if(i == blocks.end() || !i->contains(ptr, block_no))
         throw Invalid_State("Pointer released to the wrong allocator");
 
      i->free(ptr, block_no);
      }
   }

References Botan::Invalid_State::Invalid_State(), and Botan::round_up().

destroy()

void Botan::Pooling_Allocator::destroy ( )

virtualinherited

Shutdown the allocator

Reimplemented from Botan::Allocator.

Definition at line 119 of file mem_pool.cpp.

   {
   Mutex_Holder lock(mutex);
 
   blocks.clear();
 
   for(size_t j = 0; j != allocated.size(); ++j)
      dealloc_block(allocated[j].first, allocated[j].second);
   allocated.clear();
   }

get()

Allocator * Botan::Allocator::get ( bool locking )

staticinherited

Acquire a pointer to an allocator

Parameters

locking

is true if the allocator should attempt to secure the memory (eg for using to store keys)

Returns

pointer to an allocator; ownership remains with library, so do not delete

Definition at line 90 of file defalloc.cpp.

   {
   std::string type = "";
   if(!locking)
      type = "malloc";
 
   Allocator* alloc = global_state().get_allocator(type);
   if(alloc)
      return alloc;
 
   throw Internal_Error("Couldn't find an allocator to use in get_allocator");
   }

References Botan::Library_State::get_allocator(), Botan::global_state(), Botan::Internal_Error::Internal_Error(), and type().

Referenced by Botan::GMP_Engine::GMP_Engine(), and Botan::MemoryRegion< T >::init().

init()

virtual void Botan::Allocator::init ( )

inlinevirtualinherited

Initialize the allocator

Definition at line 53 of file allocate.h.

{}

Referenced by Botan::Library_State::add_allocator().

type()

std::string Botan::MemoryMapping_Allocator::type ( ) const

inlinevirtual

Returns

name of this allocator type

Implements Botan::Allocator.

Definition at line 28 of file mmap_mem.h.

{ return "mmap"; }

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The documentation for this class was generated from the following files:

• src/alloc/alloc_mmap/mmap_mem.h
• src/alloc/alloc_mmap/mmap_mem.cpp