OS Startup Process (HP-UX)

Each UNIX-based operating system seems to take a turn at creating a unique and different startup process, and HP-UX is no different than the others.

The /etc/inittab is a typical inittab file, but as installed doesn’t contain any comments to explain its entries. There is, however, a decent description in the man page inittab(4).

To configure the startup, all the parameters can be found in files in the /etc/rc.config.d directory; this directory is read by /etc/rc.config. Some startup programs read their configuration files directly, and some use /etc/rc.config to read all files.

The startup initialization files are found in /sbin/init.d (which is perhaps unlike most). /sbin/rc is run to begin the startup scripts. As mentioned, these files are in /sbin/init.d, but they are run from /sbin/rc[0-9].d directories. These directories will contain links to files in /sbin/init.d. Across all of these directories, there only needs to be two files: one to start the daemon in the right runlevel, and one in the next lower runlevel to stop it.

For example, consider the cron daemon:

# ls -1Fd /sbin/rc*.d/*cron
/sbin/rc1.d/K270cron@
/sbin/rc2.d/S730cron@

(First a note about the options to ls: -1 means list only filenames, -F adds the filetype designator at the end of the filename, and -d lists directories and not their contents.)

When HP-UX starts up (or changes to a higher runlevel) it runs start scripts (the S### scripts) as it goes from one level to the next until it reaches the desired level. When going to a lower runlevel, the system runs the kill scripts (the K### scripts) in order to stop processes.

The two listed files above (K270cron and S730cron) follow the [SK][0-9][0-9][0-9]script convention, and the file these link to is accordingly /sbin/init.d/cron. The numbers help to define the order that the scripts are run in; scripts are run in alphabetic order as defined by the (system) shell.

The startup scripts themselves are somewhat typical: a first parameter of start will start the service; a first parameter of stop will stop the service. Two other expected parameters are start_msg and stop_msg; these are used during the startup to provide a decently readable account of what is going on.

The scripts should return one of the following values as its exit value:

• 0. Success!
• 1. Failure.
• 2. Noop – translates to N/A (not applicable) during startup; script did nothing.
• 3. Script will cause a reboot (and will display /etc/rc.bootmsg if it contains anything).
• 4 and up. Treated same as 1.

All of the output from the startup and shutdown scripts is stored in /etc/rc.log (and the previous rc.log is moved to rc.log.old). Only the last two startup logs are kept. Here is a snippet of an rc.log:

Old /etc/rc.log moved to /etc/rc.log.old
 
**************************************************
HP-UX Start-up in progress
Thu Dec 13 13:56:28 CST 2007
**************************************************
 
Configure system crash dumps
Output from "/sbin/rc1.d/S080crashconf start":
----------------------------
crashconf: concurrent mode not supported on this platform
EXIT CODE: 0
 
Removing old vxvm files
Output from "/sbin/rc1.d/S090sw_clean_vxvm start":
----------------------------
 
VxVM INFO V-5-2-3360 VxVM device node check
Output from "/sbin/rc1.d/S091vxvm-nodes-check start":
----------------------------
 
VxVM INFO V-5-2-3362 VxVM general startup
Output from "/sbin/rc1.d/S092vxvm-startup start":
----------------------------

More information can be had on the rc(1m) and rc.config(4) man pages.