sbuild::auth_pam_conv_tty Class Reference

Authentication conversation handler for terminal devices. More...

#include <sbuild-auth-pam-conv-tty.h>

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List of all members.

Public Types

enum  error_code {
  CTTY, TIMEOUT, TIMEOUT_PENDING, TERMIOS,
  CONV_TYPE
}
 

Error codes.

More...
typedef custom_error< error_codeerror
 Exception type.

Public Member Functions

virtual ~auth_pam_conv_tty ()
 The destructor.
virtual auth_ptr get_auth ()
 Get the auth object.
virtual void set_auth (auth_ptr auth)
 Set the auth object.
virtual time_t get_warning_timeout ()
 Get the time at which the user will be warned.
virtual void set_warning_timeout (time_t timeout)
 Set the time at which the user will be warned.
virtual time_t get_fatal_timeout ()
 Get the time at which the conversation will be terminated with an error.
virtual void set_fatal_timeout (time_t timeout)
 Set the time at which the conversation will be terminated with an error.
virtual void conversation (auth_pam_conv::message_list &messages)
 Hold a conversation with the user.

Static Public Member Functions

static ptr create (auth_ptr auth)
 Create an auth_pam_conv_tty object.

Private Member Functions

 auth_pam_conv_tty (auth_ptr auth)
 The constructor.
int get_delay ()
 Get the time delay before the next SIGALRM signal.
std::string read_string (std::string message, bool echo)
 Read user input from standard input.

Private Attributes

weak_auth_ptr auth
 The auth object.
time_t warning_timeout
 The time to warn at.
time_t fatal_timeout
 The time to end at.
time_t start_time
 The time the current delay was obtained at.

Detailed Description

Authentication conversation handler for terminal devices.

This class is an implementation of the auth_pam_conv interface, and is used to interact with the user on a terminal (TTY) interface.

In order to implement timeouts, this class uses alarm(2). This has some important implications. Global state is modified by the object, so only one may be used at once in a single process. In addition, no other part of the process may set or unset the SIGALRM handlers and the alarm(2) timer during the time PAM authentication is proceeding.


Member Typedef Documentation

Exception type.


Member Enumeration Documentation

Error codes.

Enumerator:
CTTY 

No controlling terminal.

TIMEOUT 

Timed out.

TIMEOUT_PENDING 

Time is running out...

TERMIOS 

Failed to get terminal settings.

CONV_TYPE 

Unsupported conversation type.


Constructor & Destructor Documentation

auth_pam_conv_tty::auth_pam_conv_tty ( auth_ptr  auth  )  [private]

The constructor.

Parameters:
auth The authentication object this conversation handler will be associated with.

Referenced by create().

auth_pam_conv_tty::~auth_pam_conv_tty (  )  [virtual]

The destructor.


Member Function Documentation

void auth_pam_conv_tty::conversation ( auth_pam_conv::message_list messages  )  [virtual]

Hold a conversation with the user.

Each of the messages detailed in messages should be displayed to the user, asking for input where required. The type of message is indicated in the auth_pam_message::type field of the auth_pam_message. The auth_pam_message::response field of the auth_pam_message should be filled in if input is required.

On error, an exception will be thrown.

Parameters:
messages the messages to display to the user, and responses to return to the caller.

Implements sbuild::auth_pam_conv.

References CONV_TYPE, sbuild::DEBUG_NOTICE, sbuild::log_ctty_error(), sbuild::log_ctty_info(), sbuild::log_debug(), sbuild::auth_pam_message::MESSAGE_ERROR, sbuild::auth_pam_message::MESSAGE_INFO, sbuild::auth_pam_message::MESSAGE_PROMPT_ECHO, sbuild::auth_pam_message::MESSAGE_PROMPT_NOECHO, and read_string().

auth_pam_conv::ptr auth_pam_conv_tty::create ( auth_ptr  auth  )  [static]

Create an auth_pam_conv_tty object.

Parameters:
auth The authentication object this conversation handler will be associated with.

References auth_pam_conv_tty().

auth_pam_conv::auth_ptr auth_pam_conv_tty::get_auth (  )  [virtual]

Get the auth object.

Returns:
the auth object.

Implements sbuild::auth_pam_conv.

int auth_pam_conv_tty::get_delay (  )  [private]

Get the time delay before the next SIGALRM signal.

If either the warning timeout or the fatal timeout have expired, a message to notify the user is printed to stderr. If the fatal timeout is reached, an exception is thrown.

Returns:
the delay in seconds, or 0 if no delay is set.

References fatal_timeout, sbuild::log_ctty_exception_warning(), start_time, TIMEOUT, TIMEOUT_PENDING, and warning_timeout.

Referenced by read_string().

time_t auth_pam_conv_tty::get_fatal_timeout (  )  [virtual]

Get the time at which the conversation will be terminated with an error.

Returns:
the time.

Implements sbuild::auth_pam_conv.

References fatal_timeout.

time_t auth_pam_conv_tty::get_warning_timeout (  )  [virtual]

Get the time at which the user will be warned.

Returns:
the time.

Implements sbuild::auth_pam_conv.

References warning_timeout.

std::string auth_pam_conv_tty::read_string ( std::string  message,
bool  echo 
) [private]

Read user input from standard input.

The prompt message is printed to prompt the user for input. If echo is true, the user input it echoed back to the terminal, but if false, echoing is suppressed using termios(3).

If the SIGALRM timer expires while waiting for input, this is handled by re-checking the delay time which will warn the user or cause the input routine to terminate if the fatal timeout has expired.

Parameters:
message the message to prompt the user for input.
echo echo user input to screen.
Returns:
a string, which is empty on failure.

References sbuild::cctty, CTTY, sbuild::CTTY_FILENO, get_delay(), and TERMIOS.

Referenced by conversation().

void auth_pam_conv_tty::set_auth ( auth_ptr  auth  )  [virtual]

Set the auth object.

Parameters:
auth the auth object.

Implements sbuild::auth_pam_conv.

void auth_pam_conv_tty::set_fatal_timeout ( time_t  timeout  )  [virtual]

Set the time at which the conversation will be terminated with an error.

Parameters:
timeout the time to set.

Implements sbuild::auth_pam_conv.

References fatal_timeout.

void auth_pam_conv_tty::set_warning_timeout ( time_t  timeout  )  [virtual]

Set the time at which the user will be warned.

Parameters:
timeout the time to set.

Implements sbuild::auth_pam_conv.

References warning_timeout.


Member Data Documentation

The auth object.

The time to end at.

Referenced by get_delay(), get_fatal_timeout(), and set_fatal_timeout().

The time the current delay was obtained at.

Referenced by get_delay().

The time to warn at.

Referenced by get_delay(), get_warning_timeout(), and set_warning_timeout().


The documentation for this class was generated from the following files:
Generated on Sat Jul 10 22:17:03 2010 for sbuild by  doxygen 1.6.3