[mythtv] making mythbackend be a daemon

[Andrew Heybey]

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I do not (yet) have a computer dedicated to mythtv; I am playing with
it on the family computer.  I wanted mythbackend to start up at boot
time so that programs would be recorded automagically in the
background.  I also wanted multiple users to be able to run
mythfrontend to use mythtv.

So I made a few minor changes to the CVS version (as of about 30
December) and various changes to my system configuration and it seems
to work.  I thought it might be of interest to other people so here is
what I did.

This is on Redhat 8.0; I am a Linux newbie (I usually run FreeBSD) so
I do not know how applicable the startup script and the configuration
stuff is to other distributions.

1. Apply the attached "mythbackend.diff" patch (just a couple of
   changes).  This patch makes mythbackend work even if there is no
   DISPLAY since it no longer creates a widget.  I haven't yet tried
   to use daemon(3) but that would be the obvious next step.

2. Create a "tv" user and a "mythtv" group.  Make the home directory
   of "tv" be /usr/local/share/mythtv.  Add users who will use
   mythtv to the "mythtv" group.

3. "chown -R tv:mythtv ~tv" to give ownership of mythtv files to the
   tv user and mythtv group.  Do the same for your mythtv data
   directory if it is not underneath /usr/local/share/mythtv.

4. "chmod g+w your_mythtv_data_directory" to let members of group
   "mythtv" create and delete files in the directory where video data
   is stored.  (Not sure if this is actually required since I think
   that files are only created/deleted by mythbackend which will be
   running as the "tv" user.)

5. Change the lines dealing with sound and v4l in
   /etc/security/console.perms as follows so that the devices have
   permissions that allow mythbackend to access them.  Permission 640
   might suffice...

<console>  0660 <sound>      0660 root.mythtv
<console>  0660 <v4l>        0660 root.mythtv

6. Install the attached "mythtv.sh" script as /etc/init.d/mythtv (ie
   rename it to remove the ".sh").  Do "chkconfig mythtv on".  I had
   to put "modprobe bttv" in the script to make sure that the bttv
   module gets loaded.  I am sure that this is the Wrong Thing to do,
   but I don't understand enough about Linux yet to know the Right Thing.

7. Make sure that all the channel icons are readable by the "tv" user.

It seems to work for me, but YMMV.  One thing I thought of while
writing this email is to set the mixer setting to the proper values in
the mythtv.sh script.

andrew

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Index: programs/mythbackend/main.cpp
===================================================================
RCS file: /var/lib/cvs/MC/programs/mythbackend/main.cpp,v
retrieving revision 1.4
diff -u -u -r1.4 main.cpp
--- programs/mythbackend/main.cpp	30 Dec 2002 07:40:55 -0000	1.4
+++ programs/mythbackend/main.cpp	5 Jan 2003 02:30:11 -0000
@@ -136,7 +136,7 @@
 {
     QApplication a(argc, argv);
 
-    MythContext *context = new MythContext;
+    MythContext *context = new MythContext(false);
     context->LoadSettingsFiles("backend_settings.txt");
 
     QSqlDatabase *db = QSqlDatabase::addDatabase("QMYSQL3");
@@ -168,7 +168,9 @@
     int statusport = context->GetNumSetting("StatusPort", 6544);
 
     MainServer *ms = new MainServer(context, port, statusport, &tvList);
+#if 0
     a.setMainWidget(ms);
+#endif
 
     a.exec();
 
Index: programs/mythbackend/mainserver.h
===================================================================
RCS file: /var/lib/cvs/MC/programs/mythbackend/mainserver.h,v
retrieving revision 1.6
diff -u -u -r1.6 mainserver.h
--- programs/mythbackend/mainserver.h	30 Dec 2002 07:40:55 -0000	1.6
+++ programs/mythbackend/mainserver.h	5 Jan 2003 02:30:15 -0000
@@ -14,7 +14,7 @@
 class MythContext;
 class HttpStatus;
 
-class MainServer : public QVBox
+class MainServer : public QObject
 {
     Q_OBJECT
   public:

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#!/bin/bash=0A#=0A# mythtv	This shell script takes care of starting and sto=
pping the=0A#		mythtv back end.=0A#=0A# 80 & 10 are (respectively) just bef=
ore & after mysqld since we require it.=0A# chkconfig: - 80 10=0A# descript=
ion: Mythtv backend.=0A# processname: mythtvbackend=0A=0A# Source function =
library.=0A. /etc/rc.d/init.d/functions=0A=0Amythprefix=3D"/usr/local/share=
/mythtv"=0Aprog=3D"mythbackend"=0Apath=3D"/usr/local/bin/$prog"=0Auser=3Dtv=
=0Alog=3D"$mythprefix/${prog}.log"=0A=0Astart(){=0A    pid=3D`pidofproc $pr=
og`=0A    if [ -n "$pid" ]; then=0A	return 0=0A    fi=0A    =0A    modprobe=
 bttv=0A    touch $log=0A    chown $user $log=0A    nohup su -s /bin/bash -=
 $user -c "$path" 2>&1 > $log &=0A    [ "$?" -eq 0 ] && success $"$prog sta=
rtup" || failure $"$prog startup"=0A}=0A=0Astop(){=0A    killproc $prog=0A}=
=0A    =0Arestart(){=0A    stop=0A    start=0A}=0A=0Acondrestart(){=0A    p=
id=3D`pidofproc $prog`;=0A    [ -n "$pid" ] && restart || :=0A}=0A=0A# See =
how we were called.=0Acase "$1" in=0A  start)=0A    start=0A    ;;=0A  stop=
)=0A    stop=0A    ;;=0A  status)=0A    status $prog=0A    ;;=0A  restart)=
=0A    restart=0A    ;;=0A  condrestart)=0A    condrestart=0A    ;;=0A  *)=
=0A    echo $"Usage: $0 {start|stop|status|condrestart|restart}"=0A    exit=
 1=0Aesac=0A=0Aexit $?=0A
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