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</style>
<title>FEBUG(8)</title>
</head>
<body>
<table class="head">
<tr>
<td class="head-ltitle">FEBUG(8)</td>
<td class="head-vol">System Manager's Manual</td>
<td class="head-rtitle">FEBUG(8)</td>
</tr>
</table>
<div class="manual-text">
<section class="Sh">
<h1 class="Sh" id="NAME"><a class="permalink" href="#NAME">NAME</a></h1>
<p class="Pp"><code class="Nm">febug</code> — <span class="Nd">User-space
debugfs filesystem driver</span></p>
</section>
<section class="Sh">
<h1 class="Sh" id="SYNOPSIS"><a class="permalink" href="#SYNOPSIS">SYNOPSIS</a></h1>
<table class="Nm">
<tr>
<td><code class="Nm">febug</code></td>
<td>[<code class="Fl">-hV</code>]
[<a class="permalink" href="#libfuse"><b class="Sy" id="libfuse">libfuse
options</b></a>] <var class="Ar">mountpoint</var></td>
</tr>
</table>
</section>
<section class="Sh">
<h1 class="Sh" id="DESCRIPTION"><a class="permalink" href="#DESCRIPTION">DESCRIPTION</a></h1>
<p class="Pp"><code class="Nm">febug</code> mounts a filesystem at
<var class="Ar">mountpoint</var> that allows programs to register themselves
and expose variables to be (relatively) non-intrusively inspected at
run-time, inspired by Linux's
<a class="Lk" href="https://www.kernel.org/doc/html/latest/filesystems/debugfs.html">debugfs</a>
filesystem.</p>
<p class="Pp">See <a class="Xr">febug-abi(8)</a> for implementation details. And
the <a class="Sx" href="#EXAMPLES">EXAMPLES</a> section for an example debug
session.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="OPTIONS"><a class="permalink" href="#OPTIONS">OPTIONS</a></h1>
<p class="Pp"><code class="Fl">-h</code> <code class="Nm">or</code>
<code class="Fl">--help</code> and <code class="Fl">-V</code>
<code class="Nm">or</code> <code class="Fl">--version</code> are
self-explanatory.</p>
<p class="Pp"><code class="Nm">febug</code> passes all arguments (which have to,
therefore, include <var class="Ar">mountpoint</var>) to
<a class="Xr">fuse_main(3)</a>, with <code class="Fl">-f</code> (foreground)
and <code class="Fl">-o</code> <code class="Nm">default_permissions</code>
appended. If run with effective UID of 0, it also appends
<code class="Fl">-o</code> <code class="Nm">allow_other</code>.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="ENVIRONMENT"><a class="permalink" href="#ENVIRONMENT">ENVIRONMENT</a></h1>
<p class="Pp"><a class="permalink" href="#FEBUG_SOCKET"><i class="Em" id="FEBUG_SOCKET">FEBUG_SOCKET</i></a>
the socket at which to listen for programs, or
<span class="Pa">/var/run/febug.sock</span> by default.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="EXAMPLES"><a class="permalink" href="#EXAMPLES">EXAMPLES</a></h1>
<div class="Bd Bd-indent">
<pre>
# rcctl start febug
$ mount | grep febug
fusefs on /var/run/febug type fuse (local)
$ ./out/examples/vector-sort &
[1] 1409
$ LD_LIBRARY_PATH=out ./out/examples/string-qsort &
[2] 1410
$ ls /var/run/febug/
1409 1410
$ ls -l /var/run/febug/
dr-xr-x--- 4 nabijaczleweli users 0 Jan 15 19:52 1409
dr-xr-x--- 3 nabijaczleweli users 0 Jan 15 19:52 1410
$ ls /var/run/febug/1409/
comparisons cool_data
$ cat /var/run/febug/1409/*
24
-3 -2 -3 -2 -3 -2 3 -1 -2 -3 0 1 2 3 -1 -2 -3 0 1 2 3 -1 -2 -3 0 1 2 3 -1 2 1 0 1 2 3 -1 0 -1 0 1 2 3
$ cat /var/run/febug/1409/*
45
-3 -2 -3 -2 -3 -2 -3 -2 -2 -3 -3 -2 -1 3 -1 1 0 0 1 2 3 2 -1 3 0 1 2 3 -1 2 1 0 1 2 3 -1 0 -1 0 1 2 3
$ grep . /var/run/febug/*/*
/var/run/febug/1409/comparisons:71
/var/run/febug/1409/cool_data:-3 -3 -3 -3 -3 -3 -2 -2 -2 -2 -2 -2 -1 3 -1 1 0 0 1 2 3 2 -1 3 0 1 2 3 -1 2 1 0 1 2 3 -1 0 -1 0 1 2 3
/var/run/febug/1410/cool_data:3012987654ACEFOLJKODNIEMIGHBPPbdWwnfTpXQcreRlVvUSitZQWjRTYUazuqwertyuiopoxyhmYsgkq
$ kill %1
$ ls /var/run/febug/
1410
</pre>
</div>
</section>
<section class="Sh">
<h1 class="Sh" id="SEE_ALSO"><a class="permalink" href="#SEE_ALSO">SEE
ALSO</a></h1>
<p class="Pp"><a class="Xr" href="febug-abi.5.html">febug-abi(5)</a> — the ABI used to connect
with this filesystem.</p>
<p class="Pp"><a class="Xr" href="libfebug.3.html">libfebug(3)</a> — a library wrapping this
ABI.</p>
<p class="Pp"><a class="Xr" href="libfebug++.3.html">libfebug++(3)</a> — a C++ library wrapping
this ABI.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="AUTHORS"><a class="permalink" href="#AUTHORS">AUTHORS</a></h1>
<p class="Pp">Written by <span class="An">наб</span>
<<a class="Mt" href="mailto:nabijaczleweli@nabijaczleweli.xyz">nabijaczleweli@nabijaczleweli.xyz</a>></p>
</section>
<section class="Sh">
<h1 class="Sh" id="SPECIAL_THANKS"><a class="permalink" href="#SPECIAL_THANKS">SPECIAL
THANKS</a></h1>
<p class="Pp">To all who support further development, in particular:</p>
<ul class="Bl-bullet Bl-compact">
<li>ThePhD</li>
<li>Embark Studios</li>
</ul>
</section>
<section class="Sh">
<h1 class="Sh" id="REPORTING_BUGS"><a class="permalink" href="#REPORTING_BUGS">REPORTING
BUGS</a></h1>
<p class="Pp"><a class="Lk" href="https://todo.sr.ht/~nabijaczleweli/febug">febug
tracker</a></p>
<p class="Pp">febug mailing list:
<<a class="Mt" href="mailto:~nabijaczleweli/febug@lists.sr.ht">~nabijaczleweli/febug@lists.sr.ht</a>>
archived at
<a class="Lk" href="https://lists.sr.ht/~nabijaczleweli/febug">https://lists.sr.ht/~nabijaczleweli/febug</a></p>
</section>
</div>
<table class="foot">
<tr>
<td class="foot-date">FEBUG</td>
<td class="foot-os">OpenBSD 6.8</td>
</tr>
</table>
</body>
</html>