| The following section is a blow-by-blow account of what happens when a user logs into CDE. In this particular account, assume a distributed topology like a diskless cluster. The account begins with the boot of the hub system and nodes in step 1. By step 4, X servers are running on each node and login screens are being displayed. By step 6, the user is logged in. By step 11, the session manager is busy re-creating the user's session. The dtlogin executable is started as part of the init process that occurs during the system boot sequence on the hub machine and each cluster node. dtlogin reads /usr/dt/config/Xconfig to get a list of resources with which to configure the login process. This is where dtlogin first learns about files like Xaccess, Xservers, Xresources, Xstartup, Xsession, and Xreset and gets the values of a number of appearance and behavior resources. dtlogin reads two files in /usr/dt/config: dtlogin starts an X server and a child dtlogin for each local display. Each child dtlogin invokes dtgreet, the login screen. When a login and password are validated, a child dtlogin sets certain environment variables to default values. The child dtlogin runs /usr/dt/config/Xstartup. The child dtlogin runs /usr/dt/config/Xsession. Xsession runs dthello, the copyright screen. Xsession reads $HOME/.dtprofile, setting any additional environment variables or overwriting those set previously by dtlogin. The child dtlogin invokes the session manager, dtsession. dtsession restores the appropriate session. For example, to restore the current session, dtsession reads dt.resources and dt.session in $HOME/.dt/sessions/current.
At logout, the reverse happens. The session is saved and dtlogin runs / usr/dt/config/Xreset. After Xreset completes, dtlogin again displays the login screen, as in step 4. |
