The
misc_conv
function is part of
libpam_misc
and not of the standard
libpam
library. This function will prompt the user with the appropriate comments and obtain the appropriate inputs as directed by authentication modules.
In addition to simply slotting into the appropriate
pam_conv(3), this function provides some time-out facilities. The function exports five variables that can be used by an application programmer to limit the amount of time this conversation function will spend waiting for the user to type something. The five variabls are as follows:
time_tpam_misc_conv_warn_time;
This variable contains the
time
(as returned by
time(2)) that the user should be first warned that the clock is ticking. By default it has the value
0, which indicates that no such warning will be given. The application may set its value to sometime in the future, but this should be done prior to passing control to the
Linux-PAM
library.
const char *pam_misc_conv_warn_line;
Used in conjuction with
pam_misc_conv_warn_time, this variable is a pointer to the string that will be displayed when it becomes time to warn the user that the timeout is approaching. Its default value is a translated version of
lq...Time is running out...rq, but this can be changed by the application prior to passing control to
Linux-PAM.
time_tpam_misc_conv_die_time;
This variable contains the
time
(as returned by
time(2)) that the will time out. By default it has the value
0, which indicates that the conversation function will not timeout. The application may set its value to sometime in the future, but this should be done prior to passing control to the
Linux-PAM
library.
const char *pam_misc_conv_die_line;
Used in conjuction with
pam_misc_conv_die_time, this variable is a pointer to the string that will be displayed when the conversation times out. Its default value is a translated version of
lq...Sorry, your time is up!rq, but this can be changed by the application prior to passing control to
Linux-PAM.
intpam_misc_conv_died;
Following a return from the
Linux-PAM
libraray, the value of this variable indicates whether the conversation has timed out. A value of
1
indicates the time-out occurred.
The following two function pointers are available for supporting binary prompts in the conversation function. They are optimized for the current incarnation of the
libpamc
library and are subject to change.
This function pointer is initialized to
NULL
but can be filled with a function that provides machine-machine (hidden) message exchange. It is intended for use with hidden authentication protocols such as RSA or Diffie-Hellman key exchanges. (This is still under development.)