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/*************************************************
* Memory Mapping Allocator Source File *
* (C) 1999-2006 The Botan Project *
*************************************************/
#include <botan/mmap_mem.h>
#include <cstring>
#ifndef _XOPEN_SOURCE
#define _XOPEN_SOURCE 500
#endif
#ifndef _XOPEN_SOURCE_EXTENDED
#define _XOPEN_SOURCE_EXTENDED 1
#endif
#include <sys/types.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#ifndef MAP_FAILED
#define MAP_FAILED -1
#endif
namespace Botan {
namespace {
/*************************************************
* MemoryMapping_Allocator Exception *
*************************************************/
class MemoryMapping_Failed : public Exception
{
public:
MemoryMapping_Failed(const std::string& msg) :
Exception("MemoryMapping_Allocator: " + msg) {}
};
}
/*************************************************
* Memory Map a File into Memory *
*************************************************/
void* MemoryMapping_Allocator::alloc_block(u32bit n)
{
class TemporaryFile
{
public:
int get_fd() const { return fd; }
const std::string path() const { return filepath; }
TemporaryFile(const std::string& base)
{
const std::string path = base + "XXXXXX";
filepath = new char[path.length() + 1];
std::strcpy(filepath, path.c_str());
mode_t old_umask = umask(077);
fd = mkstemp(filepath);
umask(old_umask);
}
~TemporaryFile()
{
delete[] filepath;
if(fd != -1 && close(fd) == -1)
throw MemoryMapping_Failed("Could not close file");
}
private:
int fd;
char* filepath;
};
TemporaryFile file("/tmp/botan_");
if(file.get_fd() == -1)
throw MemoryMapping_Failed("Could not create file");
if(unlink(file.path().c_str()))
throw MemoryMapping_Failed("Could not unlink file " + file.path());
lseek(file.get_fd(), n-1, SEEK_SET);
if(write(file.get_fd(), "\0", 1) != 1)
throw MemoryMapping_Failed("Could not write to file");
void* ptr = mmap(0, n, PROT_READ | PROT_WRITE, MAP_SHARED,
file.get_fd(), 0);
if(ptr == (void*)MAP_FAILED)
throw MemoryMapping_Failed("Could not map file");
return ptr;
}
/*************************************************
* Remove a Memory Mapping *
*************************************************/
void MemoryMapping_Allocator::dealloc_block(void* ptr, u32bit n)
{
if(ptr == 0) return;
const u32bit OVERWRITE_PASSES = 12;
const byte PATTERNS[] = { 0x00, 0xFF, 0xAA, 0x55, 0x73, 0x8C, 0x5F, 0xA0,
0x6E, 0x91, 0x30, 0xCF, 0xD3, 0x2C, 0xAC, 0x53 };
for(u32bit j = 0; j != OVERWRITE_PASSES; j++)
{
std::memset(ptr, PATTERNS[j % sizeof(PATTERNS)], n);
if(msync(ptr, n, MS_SYNC))
throw MemoryMapping_Failed("Sync operation failed");
}
std::memset(ptr, 0, n);
if(msync(ptr, n, MS_SYNC))
throw MemoryMapping_Failed("Sync operation failed");
if(munmap(ptr, n))
throw MemoryMapping_Failed("Could not unmap file");
}
}
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