.\"     Title: pam_authenticate
.\"    Author: 
.\" Generator: DocBook XSL Stylesheets v1.73.1 <http://docbook.sf.net/>
.\"      Date: 04/16/2008
.\"    Manual: Linux-PAM Manual
.\"    Source: Linux-PAM Manual
.\"
.TH "PAM_AUTHENTICATE" "3" "04/16/2008" "Linux-PAM Manual" "Linux-PAM Manual"
.\" disable hyphenation
.nh
.\" disable justification (adjust text to left margin only)
.ad l
.SH "NAME"
pam_authenticate - account authentication
.SH "SYNOPSIS"
.sp
.ft B
.nf
#include <security/pam_appl\.h>
.fi
.ft
.HP 21
.BI "int pam_authenticate(pam_handle_t\ *" "pamh" ", int\ " "flags" ");"
.SH "DESCRIPTION"
.PP
The
\fBpam_authenticate\fR
function is used to authenticate the user\. The user is required to provide an authentication token depending upon the authentication service, usually this is a password, but could also be a finger print\.
.PP
The PAM service module may request that the user enter their username vio the the conversation mechanism (see
\fBpam_start\fR(3)
and
\fBpam_conv\fR(3))\. The name of the authenticated user will be present in the PAM item PAM_USER\. This item may be recovered with a call to
\fBpam_get_item\fR(3)\.
.PP
The
\fIpamh\fR
argument is an authentication handle obtained by a prior call to pam_start()\. The flags argument is the binary or of zero or more of the following values:
.PP
PAM_SILENT
.RS 4
Do not emit any messages\.
.RE
.PP
PAM_DISALLOW_NULL_AUTHTOK
.RS 4
The PAM module service should return PAM_AUTH_ERR if the user does not have a registered authentication token\.
.RE
.SH "RETURN VALUES"
.PP
PAM_ABORT
.RS 4
The application should exit immediately after calling
\fBpam_end\fR(3)
first\.
.RE
.PP
PAM_AUTH_ERR
.RS 4
The user was not authenticated\.
.RE
.PP
PAM_CRED_INSUFFICIENT
.RS 4
For some reason the application does not have sufficient credentials to authenticate the user\.
.RE
.PP
PAM_AUTHINFO_UNVAIL
.RS 4
The modules were not able to access the authentication information\. This might be due to a network or hardware failure etc\.
.RE
.PP
PAM_MAXTRIES
.RS 4
One or more of the authentication modules has reached its limit of tries authenticating the user\. Do not try again\.
.RE
.PP
PAM_SUCCESS
.RS 4
The user was successfully authenticated\.
.RE
.PP
PAM_USER_UNKNOWN
.RS 4
User unknown to authentication service\.
.RE
.SH "SEE ALSO"
.PP

\fBpam_start\fR(3),
\fBpam_setcred\fR(3),
\fBpam_chauthtok\fR(3),
\fBpam_strerror\fR(3),
\fBpam\fR(8)