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diff --git a/doc/index.html b/doc/index.html index 06e92bf..897a777 100644 --- a/doc/index.html +++ b/doc/index.html @@ -114,6 +114,7 @@ the previous versions of s6-rc and the current one. </li> <ul> <li> <a href="s6-rc-dryrun.html">The <tt>s6-rc-dryrun</tt> internal program</a> </li> <li> <a href="s6-rc-oneshot-run.html">The <tt>s6-rc-oneshot-run</tt> internal program</a> </li> + <li> <a href="s6-rc-fdholder-filler.html">The <tt>s6-rc-fdholder-filler</tt> internal program</a> </li> </ul> <h2> Related resources </h2> diff --git a/doc/s6-rc-fdholder-filler.html b/doc/s6-rc-fdholder-filler.html new file mode 100644 index 0000000..83132fd --- /dev/null +++ b/doc/s6-rc-fdholder-filler.html @@ -0,0 +1,95 @@ +<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>s6-rc: the s6-rc-fdholder-filler program</title> + <meta name="Description" content="s6-rc: the s6-rc-fdholder-filler program" /> + <meta name="Keywords" content="s6-rc dry run s6-rc-fdholder-filler internal s6-rc fdholder s6rc-fdholder pipe" /> + <!-- <link rel="stylesheet" type="text/css" href="http://skarnet.org/default.css" /> --> + </head> +<body> + +<p> +<a href="index.html">s6-rc</a><br /> +<a href="http://skarnet.org/software/">Software</a><br /> +<a href="http://skarnet.org/">skarnet.org</a> +</p> + +<h1> The s6-rc-fdholder-filler internal program </h1> + +<p> + s6-rc-fdholder-filler creates anonymous pipes and stores them into a +<a href="http://skarnet.org/software/s6/s6-fdholderd.html">s6-fdholderd</a> +"fd-holding" daemon. +</p> + +<p> + s6-rc-fdholder-filler is not meant to be used directly; it is used +in internal scripts created by +<a href="s6-rc-compile.html">s6-rc-compile</a>, which are invoked during an +<a href="s6-rc.html">s6-rc</a> execution. +</p> + +<h2> Interface </h2> + +<pre> + s6-rc-fdholder-filler [ -1 ] [ -t <em>timeout</em> ] <em>longrunnames...</em> +</pre> + +<ul> + <li> s6-rc-fdholder-filler expects file descriptor 6 to be open and +connected to the +<a href="http://skarnet.org/software/s6/s6-fdholderd.html">s6-fdholderd</a> +daemon instance managed by s6-rc as the internal <em>s6rc-fdholder</em> service. </li> + <li> For every argument <em>longrun</em> in <em>longrunnames...</em>, it +creates an anonymous pipe, and stores both ends of that pipe into the +<a href="http://skarnet.org/software/s6/s6-fdholderd.html">s6-fdholderd</a> +instance, with the <tt>pipe:s6-rc-r-<em>longrun</em></tt> (for the reading +end) and <tt>pipe:s6-rc-w-<em>longrun</em></tt> (for the writing end) +identifiers, and an infinite timeout. </li> + <li> It then exits 0. </li> +</ul> + +<h2> Options </h2> + +<ul> + <li> <tt>-1</tt> : write a newline to stdout before exiting after +successful operation. This is used as a notification mechanism. </li> + <li> <tt>-t <em>timeout</em></tt> : if the operation cannot be +achieved in <em>timeout</em> milliseconds, abort and report failure. By +default, <em>timeout</em> is 0, meaning infinite. </li> +</ul> + +<h2> Exit codes </h2> + +<ul> + <li> 0: success </li> + <li> 100: wrong usage </li> + <li> 111: system call failed </li> +</ul> + +<h2> Notes </h2> + +<ul> + <li> s6-rc-fdholder-filler is never meant to be used manually; this page +should only be used to understand s6-rc internals. </li> + <li> s6-rc-fdholder-filler is used in the <tt>s6rc-fdholder</tt> internal +service's run script, right after the +<a href="http://skarnet.org/software/s6/s6-fdholderd.html">s6-fdholderd</a> +daemon is started; its arguments are the names of all the consumer longrun +services declared in the service database. </li> + <li> The point is to create all the pipes for the longrun pipelines in +advance, every time the <tt>s6rc-fdholder</tt> service is started, and +make them available in the fd holder. This way, pipelined services +can simply retrieve their stdin (for consumers) or stdout (for producers) +from the fd holder, at any time: even if a pipeline service dies and is +restarted, the pipe will remain valid. </li> + <li> If the fd holder itself dies, it will be refilled with a new set +of pipes as soon as it is restarted. Pipelined services will not be +impacted until one of them restarts; then all the pipeline will +restart. </li> +</ul> + +</body> +</html> |