path: root/xc/workInProgress/xsm/xsm.man

.\" $XConsortium: xsm.man,v 1.6 94/08/02 17:07:36 mor Exp mor $
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.TH XSM 1 "Release 6" "X Version 11"
.SH NAME
xsm \- X Session Manager
.SH SYNOPSIS
.B xsm
[-name sessionName] [-verbose]
.SH DESCRIPTION
.PP
\fIxsm\fP is a session manager.  A session is a group of applications, each
of which has a particular state.  The purpose of the session manager is to
save and restore sessions.
.SH OPTIONS
.TP 8
.B \-name \fIsessionName\fP
Causes \fIxsm\fP to load the specified session, bypassing the session menu.
.TP 8
.B \-verbose
Turns on debugging information.
.SH SETUP
.SS .xsession file
Using \fIxsm\fP requires a few changes to your \fI.xsession\fP file:
.PP
The last program executed by your \fI.xsession\fP file should
be \fIxsm\fP.  With this configuration, when the user chooses to shut
down the session using \fIxsm\fP, the session will truly be over.
.PP
Since the goal of the session manager is to restart clients when
logging into a session, your .xsession file, in general, should not directly
start up applications.  Rather, the applications should be started within
a session.  When \fIxsm\fP shuts down the session, \fIxsm\fP will know to
restart these applications.  Note however that there are some types of
applications that are not "session aware", and these applications should be
started within the \fI.xsession\fP file.  Applications that are not session
aware are ones that do not support the X Session Management Protocol, or
they do not create any top level windows for the Session Management Proxy
to detect (see the section titled \fITHE PROXY\fP).
.PP
.SS SM_SAVE_DIR environment variable
If the \fISM_SAVE_DIR\fP environment variable is defined, \fIxsm\fP will
save all configuration files in this directory.  Otherwise, they will be
stored in the user's home directory.  Session aware applications are also
encouraged to save their checkpoint files in the \fISM_SAVE_DIR\fP directory,
although the user should not depend on this convention.
.PP
.SS Default Startup Applications
The first time \fIxsm\fP is started, it will need to locate a list of
applications to start up.  For example, this list might include a window
manager, a session management proxy, and an xterm.  \fIxsm\fP will first
look for the file \fI.xsmstartup\fP in the user's home directory.  If that
file does not exists, it will look for the \fIsystem.xsm\fP file that was
set up at installation time.  Note that \fIxsm\fP provides a "fail safe"
option when the user chooses a session to start up.  The fail safe option
simply loads the default applications described above.
.PP
Each line in the startup file should contain a command to start an application.
A sample startup file might look this:
.PP
<start of file>
.br
twm
.br
smproxy
.br
xterm -geom +150+150
.br
<end of file>
.PP
.SH STARTING A SESSION
When \fIxsm\fP starts up, it first checks to see if the user previously
saved any sessions.  If no saved sessions exist, \fIxsm\fP starts up a set
of default applications (as described above in the section titled
\fIDefault Startup Applications\fP).  If at least one session exists, a
session menu is presented.  The \fB[-name sessionName]\fR option forces the
specified session to be loaded, bypassing the session menu.
.SS The session menu
The session menu presents the user with a list of sessions to choose from.
The user can change the currently selected session with the mouse, or by
using the up and down arrows on the keyboard.
.PP
The following operations can be performed from the session menu:
.PP
.TP 22
.B Load Session
Pressing this button will load the currently selected session.  Alternatively,
hitting the Return key will also load the currently selected session, or the
user can double click a session from the list.
.TP 22
.B Delete Session
This operation will delete the currently selected session, along with all
of the application checkpoint files associated with the session.  After
pressing this button, the user will be asked to press the button a second
time in order to confirm the operation.
.TP 22
.B Default/Fail Safe
\fIxsm\fP will start up a set of default applications (as described above
in the section titled \fIDefault Startup Applications\fP).  This is useful
when the user wants to start a fresh session, or if the session configuartion
files were corrupted and the user wants a "fail safe" session.
.TP 22
.B Cancel
Pressing this button will cause \fIxsm\fP to exit.  It can also be used to
cancel a "Delete Session" operation.
.PP
.SH CONTROLLING A SESSION
After \fIxsm\fP determines which session to load, it brings up its main
user interface window, then starts up all applications that are part of
the session.  The title bar for the session manager's main window will
contain the name of the session that was loaded.
.PP
The following options are available from \fIxsm\fP's main window:
.TP 18
.B Client List
Pressing this button brings up a window containing a list of all clients that
are in the session.  For each client, the host machine that the client is
running on is presented.  As clients are added and removed from the session,
this list is updated to reflect the changes.
.br
.sp
By pressing the \fBView Properties\fR
button, the user can view the session management properties associated with
the currently selected client.
.br
.sp
By pressing the \fBClone\fR button, the user can start a copy of the selected
application.
.br
.sp
By pressing the \fBKill Client\fR button, the user can remove a client from
the session.
.br
.sp
Pressing the \fBDone\fR button removes the \fBClient List\fR window.
.TP 18
.B Name Session...
This option allows the user to assign a new name to the session.  Note
that once a session's name is changed, any state changes will only affect
the new session.  The user can take a "snapshot" of a useful session by
naming the session and performing a checkpoint (see below).
.TP 18
.B Checkpoint
By performing a checkpoint, all applications that are in the session are
asked to save their state.  Not every application will save its complete
state, but at a minimum, the session manager is guaranteed that it will
receive the command required to restart the application (along with all
command line options).  A window manager participating in the session
should guarantee that the applications will come back up with the same
window configurations.
.br
.sp
When performing a checkpoint, the user must specify a \fBSave Type\fR
which informs the applications in the session how much state they should save.
.br
.sp
The \fBLocal\fR
type indicates that the application should save enough information to restore
the state as seen by the user.  It should not affect the state as seen by
other users.  For example, an editor would create a temporary file containing
the contents of its editing buffer, the location of the cursor, etc...
.br
.sp
The \fBGlobal\fR
type indicates that the application should commit all of its data to
permanent, globally accessible storage.  For example, the editor would
simply save the edited file.
.br
.sp
The \fBBoth\fR
type indicates that the application should do both of these.  For example,
the editor would save the edited file, then create a temporary file with
information such as the location of the cursor, etc...
.br
.sp
In addition to the \fBSave Type\fR, the user must specify an
\fBInteract Style\fR.
.br
.sp
The \fBNone\fR type indicates that the application should not interact with
the user while saving state.
.br
.sp
The \fBErrors\fR type indicates that the application may interact with
the user only if an error condition arises.
.br
.sp
The \fBAny\fR type indicates that the application may interact with
the user for any purpose.  Note that \fIxsm\fP will only allow one
application to interact with the user at a time.
.TP 18
.B Shutdown
A shutdown provides all of the options found in a checkpoint, but in addition,
can cause the session to exit.  Note that if the interaction style is
\fBErrors\fR or \fBAny\fR, the user may cancel the shutdown.
.br
.sp
The user may choose to exit the session without performing a checkpoint
(an additional save type \fBNone\fR is available).
.PP
.SH THE PROXY
Since not all applications have been ported to support the X Session
Management Protocol, a proxy service exists to allow "old" clients to
work with the session manager.  In order for the proxy to detect an
application joining a session, the application must create a top level
window with the \fBWM_CLASS\fR, \fBWM_NAME\fR, \fBWM_COMMAND\fR, and
\fBWM_CLIENT_MACHINE\fR properties.
.PP
An application that support the \fBWM_SAVE_YOURSELF\fR protocol will receive
a \fBWM_SAVE_YOURSELF\fR client message each time the session manager issues
a checkpoint or shutdown.  This allows the application to save state.  If
an application does not support the \fBWM_SAVE_YOURSELF\fR protocol, then
the proxy will provide enough information to the session manager to restart
the application (using \fBWM_COMMAND\fR), but no state will be restored.
.PP
.SH REMOTE APPLICATIONS
\fIxsm\fP requires a remote execution protocol in order to restart
applications on remote machines.  Currently, \fIxsm\fP supports the
\fIrstart\fP protocol.  In order to restart an application on remote
machine \fBX\fR, machine \fBX\fR must have \fIrstart\fP installed.  In
the future, additional remote execution protocols may be supported.
.SH SEE ALSO
smproxy(1), rstart(1)
.SH AUTHORS
Ralph Mor, X Consortium
.br
Jordan Brown, Quarterdeck Office Systems