ELOG Administrator's Guide

How to set up and run your very own ELOG server

Installing and running on UNIX

ELOG is being developed and tested under Linux, and is being used on (Sparc) Solaris workstations. It should also compile and run on other UNIX flavours.

###

Installation from the RPM file:

Since version 2.0, ELOG contains a RPM file which eases the installation. Get the file `elog-x.x.x-x.i386.rpm` from the download section and execute as root `"rpm -i elog-x.x.x-x.i386.rpm"`. This will install the `elogd` daemon in `/usr/local/sbin` and the `elog` and `elconv` programs in `/usr/local/bin`. The sample configuration file `elogd.cfg` together with the sample logbook will be installed under `/usr/local/elog` and the documentation goes to `/usr/share/doc`. The elogd startup script will be installed at `/etc/rc.d/init.d/elogd`. To start the daemon, enter

`/etc/rc.d/init.d/elogd start`

It will listen under the port specified in `/usr/local/elog/elogd.cfg` which is 8080 by default. So one can connect using any browser with the URL:

`http://localhost:8080`

To start the daemon automatically, enter:

`chkconfig --add elogd`
`chkconfig --level 345 elogd on`

which will start the daemon on run levels 3,4 and 5 after the next reboot.

Note that the RPM installation creates a user and group `elog`, under which the daemon runs.

To start the daemon on non-RedHat systems, like SuSE or Solaris, a more generic startup scrips has been provided by Steve Jones in the Contributions section.

###

Installation from the tarball:

Download the latest `elog-x.x.x.tar.gz` package.

Make sure you have the libssl-dev package installed. Consult your distribution for details.

Expand the compressed TAR file with `tar -xzvf elog-x.x.x.tar.gz`. This creates a subdirectory `elog-x.x.x` where x.x.x is the version number. In that directory execute `make`, which creates the executables `elogd`, `elog` and `elconv`. On some systems like OpenBSD you have to execut `gmake`. These executables can then be copied to a convenient place like `/usr/local/bin` or `~/bin`. Alternatively, a `"make install"` will copy the daemon `elogd` to `SDESTDIR` (by default `/usr/local/sbin`) and the other files to `DESTDIR` (by default `/usr/local/bin`). These directories can be changed in the Makefile. The `elogd` executable can be started manually for testing with :

`elogd -p 8080`

where the -p flag specifies the port. Without the -p flag, the server uses the standard WWW port 80. Note that ports below 1024 can only be used if `elogd` is started under root, or the "sticky bit" is set on the executable.

When `elogd` is started under root, it attaches to the specified port and tries to fall-back to a non-root account. This is necessary to avoid security problems. It looks in the configuration file for the statements `Usr` and `Grp.`. If found, `elogd` uses that user and goupe name to run under. The names must of course be present on the system (usually `/etc/passwd` and `/etc/group`). If the statements `Usr` and `Grp.` are not present, `elogd` tries user and group `elog`, then the default user and group (normally `nogroup` and `nobody`). Care has to be taken that `elogd`, when running under the specific user and group account, has read and write access to the configuration file and logbook directories. Note that the RPM installation automatically creates a user and group `elog`.

If the program complains with something like "cannot bind to port...", it could be that the network is not started on the Linux box. This can be checked with the `/sbin/ifconfig` program, which must show that `eth0` is up and running.

The distribution contains a sample configuration file `elogd.cfg` and a demo logbook in the demo subdirectory. If the `elogd` server is started in the elogd-x.x.x directory, the demo logbook can be directly accessed with a browser by specifying the URL http://localhost:8080 (or whatever port you started the elog daemon on). If the `elogd` server is started in some other directory, you must specify the full path of the `elogd` file with the "-c" flag and change the Data dir = option in the configuration file to a full path like /usr/local/elog.

Once testing is complete, `elogd` will typically be started with the `-D` flag to run as a daemon in the background, like this :

`elogd -p 8080 -c /usr/local/elog/elogd.cfg -D`

Note that it is mandatory to specify the full path for the `elogd` file when started as a daemon.

To test the daemon, connect to your host via :

`http://your.host:8080/`

If port 80 is used, the port can be omitted in the URL. If several logbooks are defined on a host, they can be specified in the URL :

`http://your.host/<logbook>`

where `<logbook>` is the name of the logbook.

The contents of the all-important configuration file `elogd.cfg` are described below.

Notes for various platforms

### Solaris:

Martin Huber reports that under Solaris 7 the following command line is needed to compile elog:

`gcc -L/usr/lib/ -ldl -lresolv -lm -ldl -lnsl -lsocket elogd.c -o elogd`

With some combinations of Solaris servers and client-side browsers there have also been problems with ELOG's keep-alive feature. In such a case you need to add the "-k" flag to the `elogd` command line to turn keep-alives off.

###

Mac OS X:

Sridhar Anandakrishnan and Recai Oktas report that under Mac OS X there is a problem with the default stack size. The command limit stacksize unlimited (for tcsh) or ulimit -s unlimited (for bash) increases the stacksize and fixes this problem. Read the according thread in the forum.

###

FreeBSD:

David Otto maintains the ELOG port for FreeBSD. To install ELOG on a FreeBSD system, you can simply type

`cd /usr/ports/www/elog
make install clean`

Running elogd under Apache

For cases where `elogd` should run under port 80 in parallel to an Apache server, Apache can be configured to run Elog in a subdirectory of Apache. Start `elogd` normally under port 8080 (or similarly) as noted above and make sure it's working there. Then put following redirection into the Apache configuration file:

    Redirect permanent /elog http://your.host.domain/elog/
    ProxyPass /elog/ http://your.host.domain:8080/

Make sure that the Apache modules mod_proxy.c and mod_alias.c are activated. Justin Dieters <enderak@yahoo.com> reports that mod_proxy_http.c is also required. The Redirect statement is necessary to automatically append a "/" to a request like `http://your.host.domain/elog`. Apache then works as a proxy and forwards all requests staring with `/elog` to the elogd daemon.

Note: Do not put `"ProxyRequests On"` into your configuration file. This option is not necessary and can be misused for spamming and proxy forwarding of otherwise blocked sites.

Because `elogd` uses links to itself (for example in the email notification and the redirection after a submit), it has to know under which URL it is running. If you run it under a proxy, you have to add the line:

    URL = http://your.proxy.host/subdir/

into elogd.cfg.

Installing ImageMagick

When images are attached to ELOG entries, thumbnails can be created for quick preview. This works also for PDF and PostScript files. ELOG forwards any image operation to the ImageMagic and GhostScript packages, which must be installed for this to work. While these packages are installed on most Linux systems, windows users have to download and install these pagages manually. ImageMagick can be obtained from www.imagemagick.org and GhostScript can be obtained from http://pages.cs.wisc.edu/~ghost/. After the installation, it has to be made sure that both packages are in the path. This can be checked to open a command prompt and typing `identify -version`. This command should return someting like:

    C:\>identify -version
    Version: ImageMagick 6.3.8 01/25/08 Q16 http://www.imagemagick.org
    Copyright: Copyright (C) 1999-2008 ImageMagick Studio LLC

When ELOG is started interactively, it checks for the ImageMagick installation and shows a note if it is found:

    C:\Program Files\ELOG>elogd
    elogd 2.7.2 built Feb 21 2008, 20:00:42 revision 2051
    ImageMagick detected
    Indexing logbooks ... done
    Server listening on port 8080 ...

If ImageMagick is not installed, the thumbnail functions are simply disabled, but ELOG can otherwise run normally.

Installing and running in Windows

ELOG is distributed in binary (executable) form for Windows platforms. It will run happily in console mode (or "DOS box") under Windows 9x and ME. Under Windows NT and 2000 it is also possible to run it as a service (the Windows equivalent of a UNIX daemon).

Download the latest `elogxxx.exe` file and execute it. The installer puts the ELOG system into a directory you specify and adds some menu shortcuts. With these shortcuts, the daemon `elogd.exe` can be started directly and the demo logbook can be accessed with the browser. Alternatively, the `elogd.exe` daemon can be registered as a service under Windows NT/2000/XP, so it gets started automatically when windows boots. This can be selected during installation or be done manually with the start menu shortcuts.

While the pre-2.5.3 methods of installing elogd.exe as a daemon (namely FireDaemon and srvany.exe) are still possible, they are not recommended any more.

Under Windows, the ports below 1024 can be used without restriction. So if no web server is running on the same PC the ELOG daemon can be started under the standard Web port 80. This is achieved by changing the `port=8080` option in `elogd.cfg` to `port=80` and restarting elogd.

Server Configuration

The ELOG daemon `elogd` can be executed with the following options :

`

    elogd [-p port] [-n hostname/IP] [-C] [-m] [-M] [-D] [-c file] [-s dir] [-d dir] [-v] [-k] [-f file] [-x]

`

with :

- `-p <port>` TCP port number to use for the http server (if other than 80)
- `-n <hostname or IP address>` in the case of a "multihomed" server, host name or IP address of the interface ELOG should run on
- `-C <url>` clone remote elogd configuration
- `-m` synchronize logbook(s) with remote server
- `-M` synchronize with removing deleted entries
- `-l <logbook>` optionally specify logbook for -m and -M commands
- `-D` become a daemon (Unix only)
- `-c <file>` specify the configuration file (full path mandatory if -D is used)
- `-s <dir>` specify resource directory (themes, icons, ...)
- `-d <dir>` specify logbook root directory
- `-v` verbose output for debugging
- `-k` do not use TCP keep-alive
- `-f <file>` specify PID file where elogd process ID is written when server is started
- `-x` enables execution of shell commands

The appearance, functionality and behaviour of the various logbooks on an ELOG server are determined by the single `elogd.cfg` file in the ELOG installation directory.

This file may be edited directly from the file system, or from a form in the ELOG Web interface (when the Config menu item is available). In this case, changes are applied dynamically without having to restart the server. Instead of restarting the server, under Unix one can send a HUP signal like `"killall -HUP elogd"` to tell the server to re-read its configuration.

The many options of this unique but very important file are documented on the separate elogd.cfg syntax page.

To better control appearance and layout of the logbooks, `elogd.cfg` may optionally specify the use of additional files containing HTML code, and/or custom "themes" configurations. These need to be edited directly from the file system right now.

The meaning of the directory flags `-s` and `-d` is explained in the section covering the configuration options `Resource dir` and `Logbook dir` in the elogd.cfg description.

Secure Connections HOWTO

### Using elogd itself:

Starting from version 2.7.3 on, the `elogd` program supports secure connections over the Secure Socker Layer (SSL) directly. It is recommented to run elog only through secure HTTPS connections if passwords are used. Otherwise the passwords are send over the network in clear text and exposed to sniffing attacks. To use SSL, put `SSL = 1` into the config file. If the `URL =` directive is used, make sure to use `https://...` instead of `http://...` there. The ELOG distribution contains a simple self-signed certificate in the `ssl` subdirectory. One can replace this certificate and key with a real ceritficate to avoid browser pop-up windows warning about the self-signed certificate.

### Using Apache:

Another possibility is to use the Apache web server as a proxy server allowing secure connections. To do so, Apache has to be configured accordingly and a certificate has to be generated. See some instructions on how to create a certificate, and see Running elogd under Apache before on this page on how to run elogd under Apache. Once configured correctly, elogd can be accessed via http://your.host and via https://your.host simultaneously.
The redirection statement has to be changed to

    Redirect permanent /elog https://your.host.domain/elog/
    ProxyPass /elog/ http://your.host.domain:8080/

and following has to be added to the section "VirtualHOst ...:443 in /etc/httpd/conf.d/ssl.conf:

    # Proxy setup for Elog
    <Proxy *>
    Order deny,allow
    Allow from all
    </Proxy>
    ProxyPass /elog/ http://host.where.elogd.is.running:8080/
    ProxyPassReverse /elog/ http://host.where.elogd.is.running:8080/

Then, following URL statement has to be written to elogd.cfg:

    URL = https://your.host.domain/elog

There is a more detailed step-by-step instructions at the contributions section.

### Using ssh:

`elogd` can be accessed through a a SSH tunnel. To do so, open an SSH tunnel like:

    ssh -L 1234:your.server.name:8080 your.server.name

This opens a secure tunnel from your local host, port 1234, to the server host where the `elogd` daemon is running on port 8080. Now you can access `http://localhost:1234` from your browser and reach `elogd` in a secure way.

How It All Works

For the technically curious :

The concept of ELOG is very simple. The logbook functionality is implemented by a single daemon program, `elogd`, which is written in C. It contains an integrated Web server, which does not serve files like standard Web servers, but reads logbook entries from its database and formats them into HTML. Since only forms and tables are used, no Java or Javascript is necessary, which makes the logbook display very fast. The system does not use any images on purpose to reduce the amount of data to be transferred. Since the ELOG daemon contains its own http server, no additional server like Apache is required.

The "database" in which ELOG saves its entries is in plain ASCII format. One file is created for each day in the form `YYMMDDa.log` (where YY is the year, MM the month and DD the day). For ELOG versions 1.x.x, the format was `YYMMDD.log`. Messages are separated internally by the string `$@MID@$`. If this string is entered in a message (main body text or attribute), it gets converted automatically in order not to invalidate the database structure.

If attachments are submitted, they are saved as separate files named `YYMMDD_HHMMSS_name` - where in addition to the date the time is specified and `name` is the original file name of the attachment. To copy the database to another computer, only the *.log files and the attachment files need to be copied. To copy for example all files from March 2001, just select them with `0103??a.log` and `0103??_*`.