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NAME

       pam_sm_chauthtok - PAM service function for authentication token
       management

SYNOPSIS

       #define PAM_SM_PASSWORD

       #include <security/pam_modules.h>

       PAM_EXTERN int pam_sm_chauthtok(pam_handle_t *pamh, int flags,
                                       int argc, const char **argv);

DESCRIPTION

       The pam_sm_chauthtok function is the service module's implementation of
       the pam_chauthtok(3) interface.

       This function is used to (re-)set the authentication token of the user.

       Valid flags, which may be logically OR'd with PAM_SILENT, are:

       PAM_SILENT
           Do not emit any messages.

       PAM_CHANGE_EXPIRED_AUTHTOK
           This argument indicates to the module that the users authentication
           token (password) should only be changed if it has expired. This
           flag is optional and must be combined with one of the following two
           flags. Note, however, the following two options are mutually
           exclusive.

       PAM_PRELIM_CHECK
           This indicates that the modules are being probed as to their ready
           status for altering the user's authentication token. If the module
           requires access to another system over some network it should
           attempt to verify it can connect to this system on receiving this
           flag. If a module cannot establish it is ready to update the user's
           authentication token it should return PAM_TRY_AGAIN, this
           information will be passed back to the application.

           If the control value sufficient is used in the password stack, the
           PAM_PRELIM_CHECK section of the modules following that control
           value is not always executed.

       PAM_UPDATE_AUTHTOK
           This informs the module that this is the call it should change the
           authorization tokens. If the flag is logically OR'd with
           PAM_CHANGE_EXPIRED_AUTHTOK, the token is only changed if it has
           actually expired.

       The PAM library calls this function twice in succession. The first time
       with PAM_PRELIM_CHECK and then, if the module does not return
       PAM_TRY_AGAIN, subsequently with PAM_UPDATE_AUTHTOK. It is only on the
       second call that the authorization token is (possibly) changed.

RETURN VALUES

       PAM_AUTHTOK_ERR
           The module was unable to obtain the new authentication token.

       PAM_AUTHTOK_RECOVERY_ERR
           The module was unable to obtain the old authentication token.

       PAM_AUTHTOK_LOCK_BUSY
           Cannot change the authentication token since it is currently
           locked.

       PAM_AUTHTOK_DISABLE_AGING
           Authentication token aging has been disabled.

       PAM_PERM_DENIED
           Permission denied.

       PAM_TRY_AGAIN
           Preliminary check was unsuccessful. Signals an immediate return to
           the application is desired.

       PAM_SUCCESS
           The authentication token was successfully updated.

       PAM_USER_UNKNOWN
           User unknown to password service.

SEE ALSO

       pam(3), pam_chauthtok(3), pam_sm_chauthtok(3), pam_strerror(3), PAM(8)