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/* Copyright © 2005-2007 Roger Leigh <rleigh@debian.org>
*
* schroot 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 3 of the License, or
* (at your option) any later version.
*
* schroot 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, see
* <http://www.gnu.org/licenses/>.
*
*********************************************************************/
#ifndef SBUILD_AUTH_PAM_CONV_TTY_H
#define SBUILD_AUTH_PAM_CONV_TTY_H
#include <sbuild/sbuild-auth-pam-conv.h>
#include <sbuild/sbuild-auth.h>
#include <sbuild/sbuild-custom-error.h>
#include <security/pam_appl.h>
#include <security/pam_misc.h>
namespace sbuild
{
/**
* @brief 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.
*/
class auth_pam_conv_tty : public auth_pam_conv
{
public:
/// Error codes.
enum error_code
{
CTTY, ///< No controlling terminal.
TIMEOUT, ///< Timed out.
TIMEOUT_PENDING, ///< Time is running out...
TERMIOS, ///< Failed to get terminal settings.
CONV_TYPE ///< Unsupported conversation type.
};
/// Exception type.
typedef custom_error<error_code> error;
private:
/**
* The constructor.
*
* @param auth The authentication object this conversation handler
* will be associated with.
*/
auth_pam_conv_tty (auth_ptr auth);
public:
/// The destructor.
virtual ~auth_pam_conv_tty ();
/**
* Create an auth_pam_conv_tty object.
*
* @param auth The authentication object this conversation handler
* will be associated with.
* @returns a shared pointer to the created object.
*/
static ptr
create (auth_ptr auth);
virtual auth_ptr
get_auth ();
virtual void
set_auth (auth_ptr auth);
virtual time_t
get_warning_timeout ();
virtual void
set_warning_timeout (time_t timeout);
virtual time_t
get_fatal_timeout ();
virtual void
set_fatal_timeout (time_t timeout);
virtual void
conversation (auth_pam_conv::message_list& messages);
private:
/**
* @brief 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.
*/
int get_delay ();
/**
* @brief 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.
*
* @param message the message to prompt the user for input.
* @param echo echo user input to screen.
* @returns a string, which is empty on failure.
*/
std::string
read_string (std::string message,
bool echo);
/// The auth object.
weak_auth_ptr auth;
/// The time to warn at.
time_t warning_timeout;
/// The time to end at.
time_t fatal_timeout;
/// The time the current delay was obtained at.
time_t start_time;
};
}
#endif /* SBUILD_AUTH_PAM_CONV_TTY_H */
/*
* Local Variables:
* mode:C++
* End:
*/
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