Writing an Alphanumeric Pager Server for Linux

For those thinking of setting up an alphanumeric paging service or gateway, this article explains the protocols and methods involved.
Putting it All Together

Now we can fit the pieces of the puzzle together to come up with our server.

The main server will read in configuration and data files (where to find things, the list of protocols it knows about, the available devices, etc.). It then goes into its main loop.

If we support multiple devices, use waitpid and its WNOHANG option (so that the server will merely see if any subprocesses have finished, as opposed to waiting indefinitely—and blocking all other server activities until a subprocess does finish) to determine whether any jobs have finished being delivered; remove them from the queue if they have.

Then, check to see whether a device is available and a new job is ready to be delivered; if both are true, then take the following steps. First, determine the profile and the message from the job. Then, get the next available device and lock it, so our delivery will not receive any interference. After that, filter the message (if appropriate), and finally, start up a subprocess to deliver it.



Erik Max Francis is a UNIX engineer who lives in San Jose, California. His main interests are programming, Linux, physics and mathematics. He's been using Linux at home exclusively since kernel version 1.2.8 and has been reading and contributing avidly to Usenet since 1989. He can be reached via e-mail by max@alcyone.com.


One Click, Universal Protection: Implementing Centralized Security Policies on Linux Systems

As Linux continues to play an ever increasing role in corporate data centers and institutions, ensuring the integrity and protection of these systems must be a priority. With 60% of the world's websites and an increasing share of organization's mission-critical workloads running on Linux, failing to stop malware and other advanced threats on Linux can increasingly impact an organization's reputation and bottom line.

Learn More

Sponsored by Bit9

Linux Backup and Recovery Webinar

Most companies incorporate backup procedures for critical data, which can be restored quickly if a loss occurs. However, fewer companies are prepared for catastrophic system failures, in which they lose all data, the entire operating system, applications, settings, patches and more, reducing their system(s) to “bare metal.” After all, before data can be restored to a system, there must be a system to restore it to.

In this one hour webinar, learn how to enhance your existing backup strategies for better disaster recovery preparedness using Storix System Backup Administrator (SBAdmin), a highly flexible bare-metal recovery solution for UNIX and Linux systems.

Learn More

Sponsored by Storix