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| author | Laurent Bercot <ska-skaware@skarnet.org> | 2017-11-20 14:51:36 +0000 |
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| committer | Laurent Bercot <ska-skaware@skarnet.org> | 2017-11-20 14:51:36 +0000 |
| commit | 4ba5ae5776c2e9ba4f297115c19923a928cf3e87 (patch) | |
| tree | 5a67f39a64dc5df84fc20307aa95d7536890b8b5 /doc/utmps-utmpd.html | |
| download | utmps-4ba5ae5776c2e9ba4f297115c19923a928cf3e87.tar.xz | |
Initial release / rename to utmps
Diffstat (limited to 'doc/utmps-utmpd.html')
| -rw-r--r-- | doc/utmps-utmpd.html | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/doc/utmps-utmpd.html b/doc/utmps-utmpd.html new file mode 100644 index 0000000..57fa6ac --- /dev/null +++ b/doc/utmps-utmpd.html @@ -0,0 +1,77 @@ +<html> + <head> + <meta name="viewport" content="width=device-width, initial-scale=1.0" /> + <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> + <meta http-equiv="Content-Language" content="en" /> + <title>utmps: the utmps-utmpd program</title> + <meta name="Description" content="utmps: the utmps-utmpd program" /> + <meta name="Keywords" content="utmps utmp utmpd daemon service utmps-utmpd" /> + <!-- <link rel="stylesheet" type="text/css" href="//skarnet.org/default.css" /> --> + </head> +<body> + +<p> +<a href="index.html">utmps</a><br /> +<a href="//skarnet.org/software/">Software</a><br /> +<a href="//skarnet.org/">skarnet.org</a> +</p> + +<h1> The utmps-utmpd program </h1> + +<p> +utmps-utmpd manages the utmp database. It expects to be able to create, read and +modify a file named <tt>utmp</tt> in the directory it is launched in. +</p> + +<p> + It is not meant to be called directly; instead, it is expected to be run from +a script as a part of a "utmpd" +<a href="//skarnet.org/software/s6/localservice.html">local service</a>. +</p> + +<p> + The <tt>examples/</tt> subdirectory of the utmps package provides examples +on how to run such a service. + The simplest way to do so, for testing purposes, is a command line such as: +</p> +<pre>s6-ipcserver -l0 utmpd-socket utmps-utmpd</pre> +<p> + while being in the <tt>/run/utmps</tt> directory. +</p> + +<p> +<tt>/run/utmps/utmpd-socket</tt> is the default place where utmps's +implementation of the <tt>utmpx.h</tt> functions expects the utmpd +service to be. It can be changed at build time by giving the +<tt>--with-utmp-socket=PATH</tt> option to configure. +</p> + +<p> + utmps-utmpd does not listen to the socket itself: it reads from its +standard input and writes to its standard output. It relies +on a superserver such as +<a href="//skarnet.org/software/s6/s6-ipcserver.html">s6-ipcserver</a> +to manage connections to the socket. An instance of utmps-utmpd is run +for every client connection; +every instance reads the effective uid of the client in an environment +variable set by the superserver, which allows it to filter operations - +for instance, it allows any user to read from the database but it only +allows root to write to it. +</p> + +<p> + If more fine-grained authorizations are required (only allowing +certain users and groups to connect to the service), the superserver +can be configured to enforce them. +</p> + +<p> + utmps-utmpd does not need to run as root, provided it can write its file; +it is recommended to create a <em>utmp</em> user and group, dedicated to +utmps-utmpd and +<a href="utmps-wtmpd.html">utmps-wtmpd</a> operation, and run the +superserver as this user and group. +</p> + +</body> +</html> |