Signals - HP b2600 Administration Manual

page for a description of the binary format of this file. Maintenance of this file, and distribution of its
contents to remote sites for use there is left as an exercise for the reader.
The sample server also uses a host-based access control list for deciding whether or not to accept
connections from clients on a particular machine. This list initially consists of the host on which the
server is running as well as any machines listed in the file /etc/Xn.hosts, where n is the display number
of the server. Each line of the file should contain an Internet hostname (e.g., expo.lcs.mit.edu.) There
should be no leading or trailing spaces on any lines. For example:
joesworkstation
corporate.company.com
Users can add or remove hosts from this list and enable or disable access control using the xhost
command from the same machine as the server. For example:
% xhost +janesworkstation janesworkstation being added to access control list
% xhost +
% xhost -
% xhost

Signals

The X server attaches special meaning to the following signals:
SIGHUP
This signal causes the server to close all existing connections, free all resources, and restore all
defaults. It is sent by the display manager (xdm or dtlogin) whenever the main user's main
application exits to force the server to clean up and prepare for the next user.
SIGTERM
This signal causes the server to exit cleanly.
SIGUSR1
This signal is used quite differently from either of the above. When the server starts, it checks to
see if it has inherited SIGUSR1 as SIG_IGN instead of the usual SIG_DFL. In this case, the
server sends a SIGUSR1 to its parent process after it has set up the various connection schemes.
Xdm uses this feature to recognize when connecting to the server is possible.
Page 152
All hosts being allowed (access control disabled)
All hosts being restricted (access control enabled)
Access control enabled; only the following hosts are allowed:
joesworkstation
janesworkstation
corporate.company.com
Graphics Administration Guide for HP-UX 10.20