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1 swift 1.10 <?xml version='1.0' encoding='UTF-8'?>
2     <!DOCTYPE sections SYSTEM "/dtd/book.dtd">
3    
4 swift 1.1 <!-- The content of this document is licensed under the CC-BY-SA license -->
5 neysx 1.25 <!-- See http://creativecommons.org/licenses/by-sa/2.5 -->
6 swift 1.1
7 neysx 1.27 <!-- $Header: /var/cvsroot/gentoo/xml/htdocs/doc/en/handbook/hb-working-rcscripts.xml,v 1.26 2006/09/07 08:23:02 nightmorph Exp $ -->
8 swift 1.1
9     <sections>
10 swift 1.18
11 neysx 1.27 <abstract>
12     Gentoo uses a special initscript format which, amongst other features, allows
13     dependency-driven decisions and virtual initscripts. This chapter explains all
14     these aspects and explains how to deal with these scripts.
15     </abstract>
16    
17 nightmorph 1.26 <version>1.22</version>
18     <date>2006-09-07</date>
19 swift 1.18
20 swift 1.1 <section>
21     <title>Runlevels</title>
22     <subsection>
23 swift 1.4 <title>Booting your System</title>
24     <body>
25    
26     <p>
27     When you boot your system, you will notice lots of text floating by. If you pay
28     close attention, you will notice this text is the same every time you reboot
29     your system. The sequence of all these actions is called the <e>boot
30     sequence</e> and is (more or less) statically defined.
31     </p>
32    
33     <p>
34     First, your boot loader will load the kernel image you have defined in the
35     boot loader configuration into memory after which it tells the CPU to run the
36 swift 1.6 kernel. When the kernel is loaded and run, it initializes all kernel-specific
37 swift 1.4 structures and tasks and starts the <c>init</c> process.
38     </p>
39    
40     <p>
41     This process then makes sure that all filesystems (defined in
42     <path>/etc/fstab</path>) are mounted and ready to be used. Then it executes
43     several scripts located in <path>/etc/init.d</path>, which will start the
44 swift 1.8 services you need in order to have a successfully booted system.
45 swift 1.4 </p>
46    
47     <p>
48     Finally, when all scripts are executed, <c>init</c> activates the terminals
49 swift 1.14 (in most cases just the virtual consoles which are hidden beneath <c>Alt-F1</c>,
50 swift 1.4 <c>Alt-F2</c>, etc.) attaching a special process called <c>agetty</c> to it.
51     This process will then make sure you are able to log on through these terminals
52     by running <c>login</c>.
53     </p>
54    
55     </body>
56     </subsection>
57     <subsection>
58     <title>Init Scripts</title>
59 swift 1.1 <body>
60    
61 swift 1.2 <p>
62 swift 1.4 Now <c>init</c> doesn't just execute the scripts in <path>/etc/init.d</path>
63     randomly. Even more, it doesn't run all scripts in <path>/etc/init.d</path>,
64 swift 1.7 only the scripts it is told to execute. It decides which scripts to execute by
65 swift 1.4 looking into <path>/etc/runlevels</path>.
66     </p>
67    
68     <p>
69     First, <c>init</c> runs all scripts from <path>/etc/init.d</path> that have
70     symbolic links inside <path>/etc/runlevels/boot</path>. Usually, it will
71     start the scripts in alphabetical order, but some scripts have dependency
72     information in them, telling the system that another script must be run before
73     they can be started.
74     </p>
75    
76     <p>
77     When all <path>/etc/runlevels/boot</path> referenced scripts are executed,
78     <c>init</c> continues with running the scripts that have a symbolic link to them
79     in <path>/etc/runlevels/default</path>. Again, it will use the alphabetical
80     order to decide what script to run first, unless a script has dependency
81 swift 1.7 information in it, in which case the order is changed to provide a valid
82     start-up sequence.
83 swift 1.2 </p>
84    
85     </body>
86     </subsection>
87     <subsection>
88 swift 1.4 <title>How Init Works</title>
89 swift 1.2 <body>
90    
91     <p>
92 swift 1.4 Of course <c>init</c> doesn't decide all that by itself. It needs a
93     configuration file that specifies what actions need to be taken. This
94     configuration file is <path>/etc/inittab</path>.
95 swift 1.2 </p>
96    
97 swift 1.4 <p>
98 neysx 1.16 If you remember the boot sequence we have just described, you will remember
99     that <c>init</c>'s first action is to mount all filesystems. This is defined in
100     the following line from <path>/etc/inittab</path>:
101 swift 1.4 </p>
102    
103     <pre caption="The system initialisation line in /etc/inittab">
104 swift 1.2 si::sysinit:/sbin/rc sysinit
105     </pre>
106    
107     <p>
108 swift 1.4 This line tells <c>init</c> that it must run <c>/sbin/rc sysinit</c> to
109 swift 1.6 initialize the system. The <path>/sbin/rc</path> script takes care of the
110 swift 1.4 initialisation, so you might say that <c>init</c> doesn't do much -- it
111     delegates the task of initialising the system to another process.
112 swift 1.2 </p>
113    
114     <p>
115 swift 1.4 Second, <c>init</c> executed all scripts that had symbolic links in
116     <path>/etc/runlevels/boot</path>. This is defined in the following line:
117 swift 1.2 </p>
118    
119 swift 1.4 <pre caption="The system initialisation, continued">
120     rc::bootwait:/sbin/rc boot
121 swift 1.2 </pre>
122    
123     <p>
124 swift 1.4 Again the <c>rc</c> script performs the necessary tasks. Note that the option
125     given to <c>rc</c> (<e>boot</e>) is the same as the subdirectory of
126     <path>/etc/runlevels</path> that is used.
127 swift 1.2 </p>
128    
129     <p>
130 swift 1.4 Now <c>init</c> checks its configuration file to see what <e>runlevel</e> it
131     should run. To decide this, it reads the following line from
132     <path>/etc/inittab</path>:
133 swift 1.2 </p>
134    
135 swift 1.4 <pre caption="The initdefault line">
136     id:3:initdefault:
137     </pre>
138 swift 1.2
139     <p>
140 swift 1.4 In this case (which the majority of Gentoo users will use), the <e>runlevel</e>
141     id is 3. Using this information, <c>init</c> checks what it must run to start
142     <e>runlevel 3</e>:
143 swift 1.2 </p>
144    
145 swift 1.4 <pre caption="The runlevel definitions">
146 swift 1.2 l0:0:wait:/sbin/rc shutdown
147     l1:S1:wait:/sbin/rc single
148     l2:2:wait:/sbin/rc nonetwork
149     l3:3:wait:/sbin/rc default
150     l4:4:wait:/sbin/rc default
151     l5:5:wait:/sbin/rc default
152     l6:6:wait:/sbin/rc reboot
153     </pre>
154    
155     <p>
156 swift 1.4 The line that defines level 3, again, uses the <c>rc</c> script to start the
157     services (now with argument <e>default</e>). Again note that the argument of
158     <c>rc</c> is the same as the subdirectory from <path>/etc/runlevels</path>.
159 swift 1.2 </p>
160    
161     <p>
162 swift 1.4 When <c>rc</c> has finished, <c>init</c> decides what virtual consoles it should
163     activate and what commands need to be run at each console:
164 swift 1.2 </p>
165    
166 swift 1.4 <pre caption="The virtual consoles definition">
167     c1:12345:respawn:/sbin/agetty 38400 tty1 linux
168     c2:12345:respawn:/sbin/agetty 38400 tty2 linux
169     c3:12345:respawn:/sbin/agetty 38400 tty3 linux
170     c4:12345:respawn:/sbin/agetty 38400 tty4 linux
171     c5:12345:respawn:/sbin/agetty 38400 tty5 linux
172     c6:12345:respawn:/sbin/agetty 38400 tty6 linux
173     </pre>
174    
175 swift 1.1
176     </body>
177     </subsection>
178     <subsection>
179 swift 1.4 <title>What is a runlevel?</title>
180 swift 1.1 <body>
181    
182 swift 1.2 <p>
183 swift 1.4 You have seen that <c>init</c> uses a numbering scheme to decide what
184     <e>runlevel</e> it should activate. A <e>runlevel</e> is a state in which
185     your system is running and contains a collection of scripts (runlevel scripts or
186     <e>initscripts</e>) that must be executed when you enter or leave a runlevel.
187     </p>
188    
189     <p>
190     In Gentoo, there are seven runlevels defined: three internal runlevels, and four
191     user-defined runlevels. The internal runlevels are called <e>sysinit</e>,
192     <e>shutdown</e> and <e>reboot</e> and do exactly what their names imply:
193 swift 1.6 initialize the system, powering off the system and rebooting the system.
194 swift 1.4 </p>
195    
196     <p>
197     The user-defined runlevels are those with an accompanying
198     <path>/etc/runlevels</path> subdirectory: <path>boot</path>,
199     <path>default</path>, <path>nonetwork</path> and <path>single</path>. The
200     <path>boot</path> runlevel starts all system-necessary services which all other
201     runlevels use. The remaining three runlevels differ in what services they start:
202     <path>default</path> is used for day-to-day operations, <path>nonetwork</path>
203     is used in case no network connectivity is required, and <path>single</path> is
204     used when you need to fix the system.
205 swift 1.2 </p>
206    
207 swift 1.4 </body>
208     </subsection>
209     <subsection>
210     <title>Working with the Init Scripts</title>
211     <body>
212    
213 swift 1.2 <p>
214 swift 1.4 The scripts that the <c>rc</c> process starts are called <e>init scripts</e>.
215 swift 1.2 Each script in <path>/etc/init.d</path> can be executed with the arguments
216     <e>start</e>, <e>stop</e>, <e>restart</e>, <e>pause</e>, <e>zap</e>,
217     <e>status</e>, <e>ineed</e>, <e>iuse</e>, <e>needsme</e>, <e>usesme</e> or
218     <e>broken</e>.
219     </p>
220    
221     <p>
222     To start, stop or restart a service (and all depending services), <c>start</c>,
223     <c>stop</c> and <c>restart</c> should be used:
224     </p>
225    
226     <pre caption="Starting Postfix">
227     # <i>/etc/init.d/postfix start</i>
228     </pre>
229 swift 1.4
230     <note>
231     Only the services that <e>need</e> the given service are stopped or restarted.
232     The other depending services (those that <e>use</e> the service but don't need
233     it) are left untouched.
234     </note>
235 swift 1.2
236     <p>
237     If you want to stop a service, but not the services that depend on it, you can
238     use the <c>pause</c> argument:
239     </p>
240    
241     <pre caption="Stopping Postfix but keep the depending services running">
242     # <i>/etc/init.d/postfix pause</i>
243     </pre>
244    
245     <p>
246     If you want to see what status a service has (started, stopped, paused, ...) you
247     can use the <c>status</c> argument:
248     </p>
249    
250     <pre caption="Status information for postfix">
251     # <i>/etc/init.d/postfix status</i>
252     </pre>
253    
254     <p>
255 swift 1.3 If the status information tells you that the service is running, but you know
256     that it is not, then you can reset the status information to "stopped" with the
257     <c>zap</c> argument:
258 swift 1.2 </p>
259    
260     <pre caption="Resetting status information for postfix">
261     # <i>/etc/init.d/postfix zap</i>
262     </pre>
263    
264     <p>
265     To also ask what dependencies the service has, you can use <c>iuse</c> or
266     <c>ineed</c>. With <c>ineed</c> you can see the services that are really
267     necessary for the correct functioning of the service. <c>iuse</c> on the other
268     hand shows the services that can be used by the service, but are not necessary
269     for the correct functioning.
270     </p>
271    
272     <pre caption="Requesting a list of all necessary services on which Postfix depends">
273     # <i>/etc/init.d/postfix ineed</i>
274     </pre>
275    
276     <p>
277     Similarly, you can ask what services require the service (<c>needsme</c>) or can
278     use it (<c>usesme</c>):
279     </p>
280    
281     <pre caption="Requesting a list of all services that require Postfix">
282     # <i>/etc/init.d/postfix needsme</i>
283     </pre>
284    
285     <p>
286 neysx 1.16 Finally, you can ask what dependencies the service requires that are missing:
287 swift 1.2 </p>
288    
289     <pre caption="Requesting a list of missing dependencies for Postfix">
290     # <i>/etc/init.d/postfix broken</i>
291     </pre>
292 swift 1.1
293     </body>
294     </subsection>
295     </section>
296     <section>
297     <title>Working with rc-update</title>
298     <subsection>
299     <title>What is rc-update?</title>
300     <body>
301    
302 swift 1.2 <p>
303     Gentoo's init system uses a dependency-tree to decide what service needs to be
304 neysx 1.16 started first. As this is a tedious task that we wouldn't want our users to
305     have to do manually, we have created tools that ease the administration of the
306     runlevels and init scripts.
307 swift 1.2 </p>
308    
309     <p>
310     With <c>rc-update</c> you can add and remove init scripts to a runlevel. The
311     <c>rc-update</c> tool will then automatically ask the <c>depscan.sh</c> script
312     to rebuild the dependency tree.
313     </p>
314    
315 swift 1.1 </body>
316     </subsection>
317     <subsection>
318     <title>Adding and Removing Services</title>
319     <body>
320    
321 swift 1.2 <p>
322     You have already added init scripts to the "default" runlevel during the
323 swift 1.7 installation of Gentoo. At that time you might not have had a clue what the
324 swift 1.2 "default" is for, but now you should. The <c>rc-update</c> script requires a
325     second argument that defines the action: <e>add</e>, <e>del</e> or <e>show</e>.
326     </p>
327    
328     <p>
329     To add or remove an init script, just give <c>rc-update</c> the <c>add</c> or
330     <c>del</c> argument, followed by the init script and the runlevel. For instance:
331     </p>
332    
333     <pre caption="Removing Postfix from the default runlevel">
334     # <i>rc-update del postfix default</i>
335     </pre>
336    
337     <p>
338     The <c>rc-update show</c> command will show all the available init scripts and
339     list at which runlevels they will execute:
340     </p>
341    
342     <pre caption="Receiving init script information">
343     # <i>rc-update show</i>
344     </pre>
345 swift 1.1
346     </body>
347     </subsection>
348     </section>
349     <section>
350     <title>Configuring Services</title>
351     <subsection>
352 swift 1.2 <title>Why the Need for Extra Configuration?</title>
353 swift 1.1 <body>
354    
355 swift 1.2 <p>
356 neysx 1.16 Init scripts can be quite complex. It is therefore not really desirable to
357     have the users edit the init script directly, as it would make it more
358 swift 1.5 error-prone. It is however important to be able to configure such a service. For
359     instance, you might want to give more options to the service itself.
360 swift 1.2 </p>
361    
362     <p>
363 neysx 1.16 A second reason to have this configuration outside the init script is to be
364     able to update the init scripts without the fear that your configuration
365     changes will be undone.
366 swift 1.2 </p>
367    
368 swift 1.1 </body>
369     </subsection>
370     <subsection>
371     <title>The /etc/conf.d Directory</title>
372     <body>
373    
374 swift 1.2 <p>
375     Gentoo provides an easy way to configure such a service: every init script that
376     can be configured has a file in <path>/etc/conf.d</path>. For instance, the
377     apache2 initscript (called <path>/etc/init.d/apache2</path>) has a
378     configuration file called <path>/etc/conf.d/apache2</path>, which can contain
379     the options you want to give to the Apache 2 server when it is started:
380     </p>
381    
382     <pre caption="Variable defined in /etc/conf.d/apache2">
383     APACHE2_OPTS="-D PHP4"
384     </pre>
385    
386     <p>
387     Such a configuration file contains variables and variables alone (just like
388     <path>/etc/make.conf</path>), making it very easy to configure services. It also
389     allows us to provide more information about the variables (as comments).
390     </p>
391    
392 swift 1.1 </body>
393     </subsection>
394     </section>
395     <section>
396 swift 1.2 <title>Writing Init Scripts</title>
397 swift 1.1 <subsection>
398     <title>Do I Have To?</title>
399     <body>
400    
401 swift 1.2 <p>
402 neysx 1.16 No, writing an init script is usually not necessary as Gentoo provides
403 swift 1.2 ready-to-use init scripts for all provided services. However, you might have
404     installed a service without using Portage, in which case you will most likely
405     have to create an init script.
406     </p>
407    
408     <p>
409     Do not use the init script provided by the service if it isn't explicitly
410     written for Gentoo: Gentoo's init scripts are not compatible with the init
411     scripts used by other distributions!
412     </p>
413    
414 swift 1.1 </body>
415     </subsection>
416     <subsection>
417     <title>Layout</title>
418     <body>
419    
420 swift 1.2 <p>
421     The basic layout of an init script is shown below.
422     </p>
423    
424     <pre caption="Basic layout of an init script">
425     #!/sbin/runscript
426    
427     depend() {
428     <comment>(Dependency information)</comment>
429     }
430    
431     start() {
432     <comment>(Commands necessary to start the service)</comment>
433     }
434    
435     stop() {
436     <comment>(Commands necessary to stop the service)</comment>
437     }
438    
439     restart() {
440     <comment>(Commands necessary to restart the service)</comment>
441     }
442     </pre>
443    
444     <p>
445     Any init script <e>requires</e> the <c>start()</c> function to be defined. All
446     other sections are optional.
447     </p>
448    
449 swift 1.1 </body>
450     </subsection>
451     <subsection>
452     <title>Dependencies</title>
453     <body>
454    
455 swift 1.2 <p>
456     There are two dependencies you can define: <c>use</c> and <c>need</c>. As we
457     have mentioned before, the <c>need</c> dependency is more strict than the
458     <c>use</c> dependency. Following this dependency type you enter the service
459     you depend on, or the <e>virtual</e> dependency.
460     </p>
461    
462     <p>
463     A <e>virtual</e> dependency is a dependency that a service provides, but that is
464     not provided solely by that service. Your init script can depend on a system
465     logger, but there are many system loggers available (metalogd, syslog-ng,
466     sysklogd, ...). As you cannot <c>need</c> every single one of them (no sensible
467     system has all these system loggers installed and running) we made sure that
468     all these services <c>provide</c> a virtual dependency.
469     </p>
470    
471     <p>
472     Let us take a look at the dependency information for the postfix service.
473     </p>
474    
475     <pre caption="Dependency information for Postfix">
476     depend() {
477     need net
478     use logger dns
479     provide mta
480     }
481     </pre>
482    
483     <p>
484     As you can see, the postfix service:
485     </p>
486    
487     <ul>
488     <li>
489     requires the (virtual) <c>net</c> dependency (which is provided by, for
490     instance, <path>/etc/init.d/net.eth0</path>)
491     </li>
492     <li>
493     uses the (virtual) <c>logger</c> dependency (which is provided by, for
494     instance, <path>/etc/init.d/syslog-ng</path>)
495     </li>
496     <li>
497     uses the (virtual) <c>dns</c> dependency (which is provided by, for
498     instance, <path>/etc/init.d/named</path>)
499     </li>
500     <li>
501     provides the (virtual) <c>mta</c> dependency (which is common for all mail
502     servers)
503     </li>
504     </ul>
505    
506 swift 1.1 </body>
507     </subsection>
508     <subsection>
509     <title>Controlling the Order</title>
510     <body>
511    
512 swift 1.2 <p>
513     In some cases you might not require a service, but want your service to be
514     started <c>before</c> (or <c>after</c>) another service <e>if</e> it is
515     available on the system (note the conditional - this is no dependency anymore)
516 swift 1.17 <e>and</e> run in the same runlevel (note the conditional - only services in the
517 swift 1.2 same runlevel are involved). You can provide this information using the
518     <c>before</c> or <c>after</c> settings.
519     </p>
520    
521     <p>
522     As an example we view the settings of the Portmap service:
523     </p>
524    
525     <pre caption="The depend() function in the Portmap service">
526     depend() {
527     need net
528     before inetd
529     before xinetd
530     }
531     </pre>
532    
533     <p>
534     You can also use the "*" glob to catch all services in the same runlevel,
535 neysx 1.16 although this isn't advisable.
536 swift 1.2 </p>
537    
538     <pre caption="Running an init script as first script in the runlevel">
539     depend() {
540     before *
541     }
542     </pre>
543 swift 1.1
544 nightmorph 1.26 <p>
545     If your service must write to local disks, it should need <c>localmount</c>. If
546     it places anything in <path>/var/run</path> such as a pidfile, then should
547     start after <c>bootmisc</c>:
548     </p>
549    
550     <pre caption="Example depend() function">
551     depend() {
552     need localmount
553     after bootmisc
554     }
555     </pre>
556    
557 swift 1.1 </body>
558     </subsection>
559     <subsection>
560     <title>Standard Functions</title>
561     <body>
562    
563 swift 1.2 <p>
564     Next to the <c>depend()</c> functionality, you also need to define the
565     <c>start()</c> function. This one contains all the commands necessary to
566 neysx 1.16 initialize your service. It is advisable to use the <c>ebegin</c> and
567 swift 1.2 <c>eend</c> functions to inform the user about what is happening:
568     </p>
569    
570     <pre caption="Example start() function">
571     start() {
572     ebegin "Starting my_service"
573 nightmorph 1.26 start-stop-daemon --start --exec /path/to/my_service \
574     --pidfile /path/to/my_pidfile
575 swift 1.2 eend $?
576     }
577     </pre>
578    
579     <p>
580 nightmorph 1.26 Both <c>--exec</c> and <c>--pidfile</c> should be used in start and stop
581     functions. If the service does not create a pidfile, then use
582     <c>--make-pidfile</c> if possible, though you should test this to be sure.
583     Otherwise, don't use pidfiles. You can also add <c>--quiet</c> to the
584     <c>start-stop-daemon</c> options, but this is not recommended unless the
585     service is extremely verbose. Using <c>--quiet</c> may hinder debugging if the
586     service fails to start.
587 swift 1.2 </p>
588    
589 nightmorph 1.26 <note>
590     Make sure that <c>--exec</c> actually calls a service and not just a shell
591     script that launches services and exits -- that's what the init script is
592     supposed to do.
593     </note>
594    
595     <p>
596     If you need more examples of the <c>start()</c> function, please read the
597     source code of the available init scripts in your <path>/etc/init.d</path>
598     directory.
599     </p>
600 swift 1.2
601     <p>
602     Other functions you can define are: <c>stop()</c> and <c>restart()</c>. You are
603     not obliged to define these functions! Our init system is intelligent enough to
604 swift 1.9 fill these functions by itself if you use <c>start-stop-daemon</c>.
605 swift 1.2 </p>
606    
607 swift 1.21 <p>
608 nightmorph 1.26 Although you do not <e>have</e> to create a <c>stop()</c> function, here is an
609     example:
610     </p>
611    
612     <pre caption="Example stop() function">
613     stop() {
614     ebegin "Stopping my_service"
615     start-stop-daemon --stop --exec /path/to/my_service \
616     --pidfile /path/to/my_pidfile
617     eend $?
618     }
619     </pre>
620    
621     <p>
622     If your service runs some other script (for example, bash, python, or perl),
623     and this script later changes names (for example, <c>foo.py</c> to <c>foo</c>),
624     then you will need to add <c>--name</c> to <c>start-stop-daemon</c>. You must
625     specify the name that your script will be changed to. In this example, a
626     service starts <c>foo.py</c>, which changes names to <c>foo</c>:
627     </p>
628    
629     <pre caption="A service that starts the foo script">
630     start() {
631     ebegin "Starting my_script"
632     start-stop-daemon --start --exec /path/to/my_script \
633     --pidfile /path/to/my_pidfile --name foo
634     eend $?
635     }
636     </pre>
637    
638     <p>
639     <c>start-stop-daemon</c> has an excellent man page available if you need more
640     information:
641     </p>
642    
643     <pre caption="Getting the man page for start-stop-daemon">
644     $ <i>man start-stop-daemon</i>
645     </pre>
646    
647     <p>
648 swift 1.21 Gentoo's init script syntax is based on the Bourne Again Shell (bash) so you are
649     free to use bash-compatible constructs inside your init script.
650     </p>
651    
652 swift 1.1 </body>
653     </subsection>
654     <subsection>
655     <title>Adding Custom Options</title>
656     <body>
657    
658 swift 1.2 <p>
659     If you want your init script to support more options than the ones we have
660     already encountered, you should add the option to the <c>opts</c> variable, and
661     create a function with the same name as the option. For instance, to support an
662     option called <c>restartdelay</c>:
663     </p>
664    
665     <pre caption="Supporting the restartdelay option">
666     opts="${opts} restartdelay"
667    
668     restartdelay() {
669 swift 1.24 stop
670 swift 1.2 sleep 3 <comment># Wait 3 seconds before starting again</comment>
671 swift 1.24 start
672 swift 1.2 }
673     </pre>
674    
675 swift 1.1 </body>
676     </subsection>
677     <subsection>
678     <title>Service Configuration Variables</title>
679     <body>
680 swift 1.2
681     <p>
682     You don't have to do anything to support a configuration file in
683     <path>/etc/conf.d</path>: if your init script is executed, the following files
684     are automatically sourced (i.e. the variables are available to use):
685     </p>
686    
687     <ul>
688     <li><path>/etc/conf.d/&lt;your init script&gt;</path></li>
689     <li><path>/etc/conf.d/basic</path></li>
690     <li><path>/etc/rc.conf</path></li>
691     </ul>
692    
693     <p>
694     Also, if your init script provides a virtual dependency (such as <c>net</c>),
695     the file associated with that dependency (such as <path>/etc/conf.d/net</path>)
696     will be sourced too.
697     </p>
698 swift 1.1
699     </body>
700     </subsection>
701     </section>
702 swift 1.12 <section>
703     <title>Changing the Runlevel Behaviour</title>
704     <subsection>
705     <title>Who might benefit from this?</title>
706     <body>
707    
708     <p>
709     Many laptop users know the situation: at home you need to start <c>net.eth0</c>
710     while you don't want to start <c>net.eth0</c> while you're on the road (as
711     there is no network available). With Gentoo you can alter the runlevel behaviour
712     to your own will.
713     </p>
714    
715     <p>
716     For instance you can create a second "default" runlevel which you can boot that
717     has other init scripts assigned to it. You can then select at boottime what
718 dertobi123 1.15 default runlevel you want to use.
719 swift 1.12 </p>
720    
721     </body>
722     </subsection>
723     <subsection>
724 neysx 1.22 <title>Using softlevel</title>
725 swift 1.12 <body>
726    
727     <p>
728     First of all, create the runlevel directory for your second "default" runlevel.
729     As an example we create the <path>offline</path> runlevel:
730     </p>
731    
732     <pre caption="Creating a runlevel directory">
733     # <i>mkdir /etc/runlevels/offline</i>
734     </pre>
735    
736     <p>
737     Add the necessary init scripts to the newly created runlevels. For instance, if
738     you want to have an exact copy of your current <c>default</c> runlevel but
739     without <c>net.eth0</c>:
740     </p>
741    
742     <pre caption="Adding the necessary init scripts">
743 neysx 1.22 <comment>(Copy all services from default runlevel to offline runlevel)</comment>
744 neysx 1.23 # <i>cd /etc/runlevels/default</i>
745     # <i>for service in *; do rc-update add $service offline; done</i>
746 neysx 1.22 <comment>(Remove unwanted service from offline runlevel)</comment>
747     # <i>rc-update del net.eth0 offline</i>
748     <comment>(Display active services for offline runlevel)</comment>
749     # <i>rc-update show offline</i>
750     <comment>(Partial sample Output)</comment>
751     acpid | offline
752     domainname | offline
753     local | offline
754     net.eth0 |
755 swift 1.12 </pre>
756    
757     <p>
758     Now edit your bootloader configuration and add a new entry for the
759     <c>offline</c> runlevel. For instance, in <path>/boot/grub/grub.conf</path>:
760     </p>
761    
762     <pre caption="Adding an entry for the offline runlevel">
763     title Gentoo Linux Offline Usage
764     root (hd0,0)
765     kernel (hd0,0)/kernel-2.4.25 root=/dev/hda3 <i>softlevel=offline</i>
766     </pre>
767    
768     <p>
769 neysx 1.22 VoilĂ , you're all set now. If you boot your system and select the newly added
770 swift 1.12 entry at boot, the <c>offline</c> runlevel will be used instead of the
771     <c>default</c> one.
772     </p>
773    
774     </body>
775     </subsection>
776     <subsection>
777 neysx 1.22 <title>Using bootlevel</title>
778 swift 1.12 <body>
779    
780     <p>
781     Using <c>bootlevel</c> is completely analogous to <c>softlevel</c>. The only
782     difference here is that you define a second "boot" runlevel instead of a second
783     "default" runlevel.
784     </p>
785    
786     </body>
787     </subsection>
788     </section>
789 swift 1.1 </sections>

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