The pam_get_item function allows applications and PAM service modules
to access and retrieve PAM informations of item_type. Upon successful
return, item contains a pointer to the value of the corresponding
item. Note, this is a pointer to the actual data and should not be
free()'ed or over-written! The following values are supported for
The service name (which identifies that PAM stack that the PAM
functions will use to authenticate the program).
The username of the entity under whose identity service will be
given. That is, following authentication, PAM_USER identifies the
local entity that gets to use the service. Note, this value can
be mapped from something (eg., "anonymous") to something else
(eg. "guest119") by any module in the PAM stack. As such an
application should consult the value of PAM_USER after each call
to a PAM function.
The string used when prompting for a user's name. The default
value for this string is a localized version of "login: ".
The terminal name: prefixed by /dev/ if it is a device file; for
graphical, X-based, applications the value for this item should
be the $DISPLAY variable.
The requesting user name: local name for a locally requesting
user or a remote user name for a remote requesting user.
Generally an application or module will attempt to supply the
value that is most strongly authenticated (a local account before
a remote one. The level of trust in this value is embodied in the
actual authentication stack associated with the application, so
it is ultimately at the discretion of the system administrator.
PAM_RUSER@PAM_RHOST should always identify the requesting user.
In some cases, PAM_RUSER may be NULL. In such situations, it is
unclear who the requesting entity is.
The requesting hostname (the hostname of the machine from which
the PAM_RUSER entity is requesting service). That is
PAM_RUSER@PAM_RHOST does identify the requesting user. In some
applications, PAM_RHOST may be NULL. In such situations, it is
unclear where the authentication request is originating from.
The authentication token (often a password). This token should be
ignored by all module functions besides pam_sm_authenticate(3)
and pam_sm_chauthtok(3). In the former function it is used to
pass the most recent authentication token from one stacked module
to another. In the latter function the token is used for another
purpose. It contains the currently active authentication token.
The old authentication token. This token should be ignored by all
module functions except pam_sm_chauthtok(3).
The pam_conv structure. See pam_conv(3).
The following additional items are specific to Linux-PAM and should
not be used in portable applications:
A function pointer to redirect centrally managed failure delays.
The name of the X display. For graphical, X-based applications
the value for this item should be the $DISPLAY variable. This
value may be used independently of PAM_TTY for passing the name
of the display.
A pointer to a structure containing the X authentication data
required to make a connection to the display specified by
PAM_XDISPLAY, if such information is necessary. See
The default action is for the module to use the following prompts
when requesting passwords: "New UNIX password: " and "Retype UNIX
password: ". The example word UNIX can be replaced with this
item, by default it is empty. This item is used by
If a service module wishes to obtain the name of the user, it should
not use this function, but instead perform a call to pam_get_user(3).
Only a service module is privileged to read the authentication
tokens, PAM_AUTHTOK and PAM_OLDAUTHTOK.
The application attempted to set an undefined or inaccessible
Memory buffer error.
The value of item was NULL.
Data was successful updated.
The pam_handle_t passed as first argument was invalid.
This page is part of the linux-pam (Pluggable Authentication Modules
for Linux) project. Information about the project can be found at
⟨https://fedorahosted.org/linux-pam/⟩. If you have a bug report for
this manual page, see ⟨https://fedorahosted.org/linux-pam/report⟩.
This page was obtained from the tarball Linux-PAM-1.3.0.tar.gz
fetched from ⟨http://www.linux-pam.org/library/⟩ on 2017-03-13. If
you discover any rendering problems in this HTML version of the page,
or you believe there is a better or more up-to-date source for the
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Linux-PAM Manual 04/01/2016 PAM_GET_ITEM(3)