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Overview of the Apache TPF Port


[ Configuration Files | What's Available | CGI Scripts | Options | Syslog | Porting Notes ]

This version of Apache includes changes allowing it to run on IBM's EBCDIC-based TPF (Transaction Processing Facility) operating system.
Unless otherwise noted TPF version 4.1 PUT09 is required. 

Refer to install-tpf.html for step-by-step installation instructions. 

This port builds upon the EBCDIC changes previously made to Apache. 

Apache Configuration Files

The distributed configuration files (httpd.conf-dist and mime.types, both located in the conf subdirectory) work on TPF. Performance considerations may dictate setting KeepAlive to "Off" (the default is "On") or lowering the Timeout value from the default 300 seconds (5 minutes) in order to reduce the number of active ECBs on your system.

Apache on TPF does not support listening on multiple ports.

What's Available in this Version

The Apache organization provides online documentation describing the various modules and components of the server. 

Components/modules tested on TPF:

Components/modules not yet supported on TPF:

Components/modules that don't apply or that probably won't ever be available on TPF:

How to Use CGI Scripts

The following is a very simple example of a CGI script ("Hello World") and the necessary steps to run it.
Refer to the mod_cgi module for additional information.

Add necessary directives to httpd.conf:

Example:
ScriptLog logs/script_log
ScriptAlias /cgi-bin/ /usr/local/apache/cgi-bin/

A request for http://myserver/cgi-bin/filename.cgi would cause the server to run the script /usr/local/apache/cgi-bin/filename.cgi

Create the CGI script:

For this example QZZ1 is the name of the TPF program that will be executed by the CGI script.
The directory path must match what is in the httpd.conf file for ScriptAlias directive.

zfile echo "#!QZZ1" > /usr/local/apache/cgi-bin/filename.cgi
zfile cat /usr/local/apache/cgi-bin/filename.cgi    
(this should display #!QZZ1)

Mark the script as executable:

zfile chmod 755 /usr/local/apache/cgi-bin/filename.cgi

Create, load, and activate a loadset containing the CGI program (QZZ1xx):

/** QZZ1-- simple "Hello world" program to demonstrate basic CGI output **/

#include <stdio.h>

void main() {

/** Print the CGI response header, required for all HTML output. **/
/** Note the extra \n, to send the blank line. **/

printf("Content-type: text/html\n\n");

/** Print the HTML response page to stdout. **/
printf("<html>\n");
printf("<head><title> CGI Output </title></head>\n");
printf("<body>\n");
printf("<h1> Hello world </h1> \n");
printf("</body>\n");
printf("</html>\n");

}

Request the CGI script from a browser:

http://myserver/cgi-bin/filename.cgi

How to Use Apache's "Dash" Options

Overview of Apache's "dash" options:

Apache can be invoked with various options, such as "-f". Some of these options display information about the server or perform syntax checks but they don't actually start the server. These "information only" options are useful with TPF's ZFILE command line feature: -h, -l, -L, -S, -t, -T, -v, and -V.

Another option, -X, is used when actually running the server. It is passed to Apache through the ZINET XPARM field since ZINET is the only way to start the server on TPF.

A third group of options apply to both the informational displays (ZFILE) and running the server (ZINET XPARM): -d, -D and -f.

The rest of Apache's options are either not applicable or are not supported on TPF.

Using dash options requires PJ27277 which shipped on PUT13.

Table of supported Apache options

Option         ZFILE ZINET Description
-d path ZFILE ZINET Set the initial value for the ServerRoot directive.
-D define ZFILE ZINET Set a configuration parameter which can be used with <IfDefine>...</IfDefine> sections in the configuration file to conditionally skip or process commands.
-f filename ZFILE ZINET Use an alternate configuration file instead of the default conf/httpd.conf file.
-h ZFILE   List a short summary of available command line options then exit. Note that this outputs all options, not just those supported on TPF.
-l ZFILE   List modules compiled into the server then exit.
-L ZFILE   List available configuration directives then exit. Note that this outputs all configuration directives, not just those supported on TPF.
-S ZFILE   Show the settings as parsed from the configuration file then exit. Currently Apache only shows the virtual host settings.
-t ZFILE   Run syntax tests for configuration files with document root checks then exit.
-T ZFILE   Run syntax tests for configuration files without document root checks then exit.
-v ZFILE   Show the version number then exit.
-V ZFILE   Show the version number and various compile settings then exit.
-X   ZINET Run in single-process mode for internal debugging purposes only. The parent process does not fork any children.

See http://httpd.apache.org/docs/programs/httpd.html for more information about these command line options.

Setup for ZFILE examples

Ensure Apache (CHTA) is loaded

Create the httpd script:

zfile echo "#!CHTA" > /bin/httpd
zfile cat /bin/httpd  
(this should display #!CHTA)


Mark the script as executable:

zfile chmod 755 /bin/httpd

(See "ZFILE-Activate a TPF Segment or Script" in the Operations guide for more information: http://www.ibm.com/tpf/pubs/tpfpubs.htm.)

ZFILE example 1

zfile httpd -v

FILE0001I 11.43.09 START OF DISPLAY FROM httpd -v
Server version: Apache/1.3.20 (TPF)
Server built: May 23 2001 09:39:22
END OF DISPLAY

ZFILE example 2

zfile httpd -t -f /usr/local/apache/conf/alt.conf

FILE0002I 11.47.26 START OF ERROR DISPLAY FROM httpd -t ...
Syntax OK
END OF DISPLAY

ZINET XPARM example

This example uses an alternate configuration file called /usr/local/apache/conf/alt.conf.
Transfer the alternate configuration file to your TPF test system.
zinet add s-apache pgm-chta model-daemon user-root xparm--f conf/alt.conf
zinet start s-apache

(See "ZINET ADD-Add an Internet Server Application Entry" and "ZINET ALTER-Change an Internet Server Application Entry" in the Operations guide for more information about using the XPARM field: http://www.ibm.com/tpf/pubs/tpfpubs.htm.)

Syslog Daemon

Syslog overview:

The syslog daemon is a server process that provides a message logging facility for application and system processes. It can be used to write messages to log files or to tapes. See TPF Transmission Control Protocol/Internet Protocol for detailed information about using the syslog daemon on TPF: http://www.ibm.com/tpf/pubs/tpfpubs.htm. And see the Apache ErrorLog directive documentation for details on how to use syslog with Apache.

Syslog capabilities were added with PJ27214 which shipped with PUT13. You must follow the syslog specific installation instructions in order to have the option of using syslog with Apache.

Tips on using syslog with your Apache error log:

This section provides some tips on using syslog with Apache. It is not meant to replace the syslog documentation in the TPF TCP/IP publication.

Porting Notes

Changes made due to differences between UNIX and TPF's process models:

Find that function...

Some simple functions & definitions initially needed to be added on TPF, such as FD_SET(). We've put these in src/os/tpf/os.h for now. 

EBCDIC changes:

TPF-specific conversion tables between US-ASCII and EBCDIC (character set IBM-1047 to be exact) were created. 

Miscellaneous, minor changes:

Various minor changes (such as casting) were made due to differences in how some functions are implemented on TPF. 

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