From: Petter Reinholdtsen <pere@hungry.com>
Date: Sun, 6 Jun 2010 21:59:38 +0000 (+0000)
Subject: New entry.
X-Git-Url: http://pere.pagekite.me/gitweb/homepage.git/commitdiff_plain/6ff737bc8ac10efd2ab793aa2bdf8ec3f7acd5bb

New entry.
---

diff --git a/blog/data/2010-06-06-upstart.txt b/blog/data/2010-06-06-upstart.txt
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+Title: Upstart or sysvinit - as init.d scripts see it
+Tags: english, debian, debian edu
+Date: 2010-06-06 23:55
+
+<p>If Debian is to migrate to upstart on Linux, I expect some init.d
+scripts to migrate (some of) their operations to upstart, and will
+need a way to behave differently when used with sysvinit and with
+upstart.  Because of this, I had a look at the environment variables
+set when a init.d script is running under upstart, and when it is
+not.</p>
+
+<p>With upstart, I notice these environment variables are set like
+this for a script started from rcS.d/ (ignoring some irrelevant
+ones):</p>
+
+<blockquote><pre>
+DEFAULT_RUNLEVEL=2
+previous=N
+PREVLEVEL=
+RUNLEVEL=
+runlevel=S
+UPSTART_EVENTS=startup
+UPSTART_INSTANCE=
+UPSTART_JOB=rc-sysinit
+</pre></blockquote>
+
+<p>With sysvinit, these environment variables are set for the same
+script.</p>
+
+<blockquote><pre>
+INIT_VERSION=sysvinit-2.88
+previous=N
+PREVLEVEL=N
+RUNLEVEL=S
+runlevel=S
+</pre></blockquote>
+
+<p>The RUNLEVEL and PREVLEVEL environment variables passed on from
+sysvinit is not set by upstart.  Not sure if it is intentional or not
+to not be compatible with sysvinit in this regard.</p>
+
+<p>For scripts needing to behave differently when upstart is used,
+looking for the UPSTART_JOB environment variable seem to be a good
+choice.</p>