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libdar::secu_string Class Reference

class secu_string More...

#include <secu_string.hpp>

Inherits libdar::on_pool.

Public Member Functions

 secu_string (U_I storage_size=0)
 
 secu_string (const char *ptr, U_I size)
 
 secu_string (const secu_string &ref)
 the copy constructor
 
secu_stringoperator= (const secu_string &ref)
 the assignment operator
 
bool operator!= (const std::string &ref) const
 
bool operator!= (const secu_string &ref) const
 
bool operator== (const std::string &ref) const
 
bool operator== (const secu_string &ref) const
 
 ~secu_string () throw (Ebug)
 the destructor (set memory to zero before releasing it)
 
void set (int fd, U_I size)
 
void append_at (U_I offset, const char *ptr, U_I size)
 
void append_at (U_I offset, int fd, U_I size)
 append some data to the string
 
void append (const char *ptr, U_I size)
 append some data at the end of the string
 
void append (int fd, U_I size)
 append some data at the end of the string
 
void reduce_string_size_to (U_I pos)
 
void clear ()
 clear the string (set to an empty string)
 
void resize (U_I size)
 
void randomize (U_I size)
 
const char * c_str () const
 get access to the secure string More...
 
char & operator[] (U_I index)
 
char operator[] (U_I index) const
 
U_I get_size () const
 get the size of the string
 
U_I get_allocated_size () const
 get the size of the allocated secure space
 
- Public Member Functions inherited from libdar::on_pool
void * operator new (size_t n_byte)
 
void * operator new (size_t n_byte, const std::nothrow_t &nothrow_value)
 
void * operator new[] (size_t n_byte)
 
void * operator new[] (size_t n_byte, const std::nothrow_t &nothrow_value)
 
void * operator new (size_t n_byte, memory_pool *p)
 
void * operator new[] (size_t n_byte, memory_pool *p)
 
void operator delete (void *ptr, memory_pool *p)
 this operator is called by the compiler if an exception is throw from the constructor of the allocated object
 
void operator delete[] (void *ptr, memory_pool *p)
 this operator is called by the compiler if an exception is throw from the constructor of the allocated objects
 
void operator delete (void *ptr)
 this is the usual delete operator, modified to handle allocated objects allocated on a memory pool or not
 
void operator delete[] (void *ptr)
 this is the usual delete[] operator, modified to handle allocated objects allocated on a memory pool or not
 

Static Public Member Functions

static bool is_string_secured ()
 

Additional Inherited Members

- Protected Member Functions inherited from libdar::on_pool
memory_pool * get_pool () const
 
template<class T >
void meta_new (T *&ptr, size_t num)
 
template<class T >
void meta_delete (T *ptr)
 

Detailed Description

class secu_string

it manages the allocation/release of a given size block of memory and let the user feed it from a filedescriptor and access to it under with a char* pointer. if more constructor are needed (espetially toward API), tell me, but this is a non-sens to build a secure string from another data structure which is not yet secured, where from the read() method that fetches data directly from a filedescriptor (read() low-level system call) which might be a tty for example

Definition at line 57 of file secu_string.hpp.

Constructor & Destructor Documentation

libdar::secu_string::secu_string ( U_I  storage_size = 0)
inline

constructor 1

create the allocated string in secure memory

Parameters
[in]storage_sizeis the amount of secured memory to obtain when creating the object

Definition at line 72 of file secu_string.hpp.

libdar::secu_string::secu_string ( const char *  ptr,
U_I  size 
)
inline

constructor 2

create the string from a pointer to a (secure) string or from a portion of it

Definition at line 77 of file secu_string.hpp.

References append_at().

Member Function Documentation

void libdar::secu_string::append_at ( U_I  offset,
const char *  ptr,
U_I  size 
)

append some data to the string at a given offset

Parameters
[in]offsetdefines at which offset in the secu_string will be placed the string to append
[in]ptris the address of the string to append
[in]sizeis the number of byte to append
Note
this call does not change the allocation size, (unlike read()), it adds the data pointed by the arguments to the object while there is enough place to do so. resize() must be used first to define enough secure memory to append the expected amount of data in one or several call to append.

Referenced by append(), and secu_string().

const char* libdar::secu_string::c_str ( ) const
inline

get access to the secure string

Returns
the address of the first byte of the string
Note
check the "size" method to know how much bytes can be read

Definition at line 144 of file secu_string.hpp.

static bool libdar::secu_string::is_string_secured ( )
static

to know if secure memory is available

it is advised that the user program of class secu_string uses this call before using objects of that class and if returned false, advise the user that the necessary support for secure memory is not present, that any sensitive data may be swapped out under heavy memory load and thus may lead secure password to be wrote to disk in clear.

char& libdar::secu_string::operator[] ( U_I  index)

get access to the secure string by index

Note
index must be in the range [ 0 - size() [ to avoid throwing an exception
void libdar::secu_string::randomize ( U_I  size)

set the string to randomize string of given size

Note
the given size must be less than allocated size
void libdar::secu_string::reduce_string_size_to ( U_I  pos)

shorten the string (do not change the allocated size)

Parameters
[in]posis the length of the string to set, it must be smaller or equal to the current size
void libdar::secu_string::resize ( U_I  size)
inline

clear and resize the string to the defined allocated size

Parameters
[in]sizeis the amount of secure memory to allocated

Definition at line 133 of file secu_string.hpp.

void libdar::secu_string::set ( int  fd,
U_I  size 
)

fill the object with data

set at most size bytes of data directly from the filedescriptor,

Parameters
[in]fdthe filedescriptor to read data from
[in]sizeis the maximum number of byte read
Note
if current storage size is not larg enough to hold size bytes, allocated secure memory is released and larger allocation of secure memory is done.

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