User's Manual

PAD Ser vices
Remote PAD Printer Support (x29printd)
Chapter 6139
CAUTION Use extreme caution when specifying applications other than the default
(login) application. Since the x29server process is started with
superuser privileges, it gives root privileges to applications triggered by
incoming calls.
You can automatically launch a user application by:
• configuring the application field with the relevant application
name as its value without specifying the cud field. The application
name must be the full path name of the application to be launched.
• configuring the application field with the application name and
setting the cud field to yes. In this case, the cud field is considered as
the argument to the application. The application name must be the
full path name of the application to be launched.
• not including the application field and setting the cud field to yes.
This allows the application to be defined by the incoming Call
Request Packet.
The first four bytes of the CUD field (in call request packets) are NOT
part of the application’s full path name. The first four bytes are used for
protocol ID as explained in the section “Call acceptance mechanism and
system security.”
Remote PAD Printer Support (x29printd)
Overview
The x29printd user-level program provides support for printers
attached to remote PADs. It accesses X.25 level 3 through Berkeley
Sockets (programmatic interface). It also has an interface to special
PTYs (see illustration below).