pam_elogind - Register user sessions in the elogind login manager
pam_elogind registers user sessions with the elogind login manager
elogind(8), and hence the elogind control group hierarchy.
On login, this module — in conjunction with elogind
— ensures the following:
1.If it does not exist yet, the user runtime directory
/run/user/$UID is either created or mounted as new "tmpfs" file
system with quota applied, and its ownership changed to the user that is
2.The $XDG_SESSION_ID environment variable is
initialized. If auditing is available and pam_loginuid.so was run
before this module (which is highly recommended), the variable is initialized
from the auditing session id (/proc/self/sessionid). Otherwise, an independent
session counter is used.
On logout, this module ensures the following:
1.If enabled in logind.conf(5)
), all processes of the session are
2.If the last concurrent session of a user ends, the
user runtime directory /run/user/$UID and all its contents are removed,
The following options are understood:
Takes a string argument which sets the session class. The
XDG_SESSION_CLASS environmental variable takes precedence. One of
"user", "greeter", "lock-screen" or
"background". See sd_session_get_class(3)
for details about
the session class.
Takes a string argument which sets the session type. The
XDG_SESSION_TYPE environmental variable takes precedence. One of
"unspecified", "tty", "x11", "wayland"
or "mir". See sd_session_get_type(3)
for details about the
Takes an optional boolean argument. If yes or without the
argument, the module will log debugging information as it operates.
MODULE TYPES PROVIDED¶
Only session is provided.
The following environment variables are set for the processes of the user's
A session identifier, suitable to be used in filenames.
The string itself should be considered opaque, although often it is just the
audit session ID as reported by /proc/self/sessionid. Each ID will be assigned
only once during machine uptime. It may hence be used to uniquely label files
or other resources of this session.
Path to a user-private user-writable directory that is
bound to the user login time on the machine. It is automatically created the
first time a user logs in and removed on the user's final logout. If a user
logs in twice at the same time, both sessions will see the same
$XDG_RUNTIME_DIR and the same contents. If a user logs in once, then
logs out again, and logs in again, the directory contents will have been lost
in between, but applications should not rely on this behavior and must be able
to deal with stale files. To store session-private data in this directory, the
user should include the value of $XDG_SESSION_ID in the filename. This
directory shall be used for runtime file system objects such as AF_UNIX
sockets, FIFOs, PID files and similar. It is guaranteed that this directory is
local and offers the greatest possible file system feature set the operating
system provides. For further details, see the XDG Base Directory
Specification. $XDG_RUNTIME_DIR is not set if the current user
is not the original user of the session.
The following environment variables are read by the module and may
be used by the PAM service to pass metadata to the module:
The session type. This may be used instead of
session= on the module parameter line, and is usually preferred.
The session class. This may be used instead of
class= on the module parameter line, and is usually preferred.
A single, short identifier string for the desktop
environment. This may be used to indicate the session desktop used, where this
applies and if this information is available. For example: "GNOME",
or "KDE". It is recommended to use the same identifiers and
capitalization as for $XDG_CURRENT_DESKTOP
, as defined by the
Desktop Entry Specification
. (However, note that
only takes a single item, and not a
colon-separated list like $XDG_CURRENT_DESKTOP
for more details.
The seat name the session shall be registered for, if
The VT number the session shall be registered for, if
any. (Only applies to seats with a VT available, such as
If not set, pam_elogind will determine the values for
$XDG_SEAT and $XDG_VTNR based on the $DISPLAY
PAM modules earlier in the stack, that is those that come before
pam_elogind.so, can set session scope limits using the PAM context
objects. The data for these objects is provided as NUL-terminated C strings
and maps directly to the respective unit resource control directives. Note
that these limits apply to individual sessions of the user, they do not apply
to all user processes as a combined whole.
See elogind.resource-control(5) for more information about
the resources. Also, see pam_set_data(3) for additional information
about how to set the context objects.
Sets unit MemoryMax=.
Sets unit TasksMax=.
Sets unit CPUWeight=.
Sets unit IOWeight=.
Example data as can be provided from an another PAM module:
pam_set_data(handle, "elogind.memory_max", (void *)"200M", cleanup);
pam_set_data(handle, "elogind.tasks_max", (void *)"50", cleanup);
pam_set_data(handle, "elogind.cpu_weight", (void *)"100", cleanup);
pam_set_data(handle, "elogind.io_weight", (void *)"340", cleanup);
auth required pam_unix.so
auth required pam_nologin.so
account required pam_unix.so
password required pam_unix.so
session required pam_unix.so
session required pam_loginuid.so
session required pam_elogind.so
- XDG Base Directory Specification
- Desktop Entry Specification