NAME

       oath_authenticate_usersfile - API function

SYNOPSIS

       #include <oath.h>

       int  oath_authenticate_usersfile(const  char * usersfile, const char * username, const char * otp, size_t
       window, const char * passwd, time_t * last_otp);

ARGUMENTS

       const char * usersfile
                   string with user credential filename, in UsersFile format

       const char * username
                   string with name of user

       const char * otp
                   string with one-time password to authenticate

       size_t window
                   how many past/future OTPs to search

       const char * passwd
                   string with password, or NULL to disable password checking

       time_t * last_otp
                   output variable holding last successful authentication

DESCRIPTION

       Authenticate user named  username  with  the  one-time  password  otp  and  (optional)  password  passwd.
       Credentials are read (and updated) from a text file named usersfile.

       Note that for TOTP the usersfile will only record the last OTP and use that to make sure more recent OTPs
       have not been seen yet when validating a new OTP.  That logics relies on using the same search window for
       the same user.

RETURNS

       On  successful validation, OATH_OK is returned.  If the supplied otp is the same as the last successfully
       authenticated  one-time  password,  OATH_REPLAYED_OTP  is  returned  and  the  timestamp  of   the   last
       authentication  is  returned  in last_otp.  If the one-time password is not found in the indicated search
       window, OATH_INVALID_OTP is returned.  Otherwise, an error code is returned.

REPORTING BUGS

       Report bugs to <oath-toolkit-help@nongnu.org>.  liboath home  page:  https://www.nongnu.org/oath-toolkit/
       General help using GNU software: http://www.gnu.org/gethelp/

COPYRIGHT

       Copyright © 2009-2020 Simon Josefsson.
       Copying  and distribution of this file, with or without modification, are permitted in any medium without
       royalty provided the copyright notice and this notice are preserved.

liboath                                              2.6.11                       oath_authenticate_usersfile(3)