Fwd: Console only boot option

[Anthony Jenkins]

On 09/01/16 14:50, Allan Jude wrote:
> On 2016-09-01 14:46, Colin Percival wrote:
>>
>>
>> -------- Forwarded Message --------
>> Subject: Console only boot option
>> Date: Thu, 1 Sep 2016 11:22:23 -0400
>> From: Anthony Jenkins via freebsd-x11 <freebsd-x11 at freebsd.org>
>> Reply-To: Anthony Jenkins <Scoobi_doo at yahoo.com>
>> To: freebsd-x11 at freebsd.org <freebsd-x11 at freebsd.org>
>>
>> I have a patch against base that adds an option "Console" to the Boot
>> Options sub-menu to prevent a GUI desktop port from being started:
>>
>>     1. Back to Main Menu [Backspace]
>>     2. Load System Defaults
>>
>>     Boot Options:
>>     3. Safe Mode... Off
>>     4. Single User. Off
>>     5. Verbose..... off
>>     6. Console..... off
>>
>>
>> When set to "On", a kernel environment variable "boot_console" is set to
>> "YES"; else "boot_console" is unset.  A GUI desktop startup script in
>> ${LOCALBASE}/etc/rc.d/ should read this variable and, if set, should
>>
>>   * Ignore a command to start the GUI
>>   * Unset "boot_console" (this allows one to manually start the GUI
>>     after initial boot).
>>
>> I'm open to suggestions about semantics to make this functionality
>> clearer (e.g. "Console..... On" is not intuitive).
>>
>> The problem I have is in the GUI startup scripts, which must be modified
>> to make this work.  What I *want* is to make a *simple* modification to
>> all GUI startup scripts (e.g. ${LOCALBASE}/etc/rc.d/kdm4) such that
>> /etc/rc knows what scripts are "GUI startup scripts" and, if
>> $boot_console is set, performs the above 2 actions.  Right now, for me
>> to make this patch work, I have to add code to my kdm4 startup script to
>> do this, which would be ugly to add to every GUI startup script in ports.
>>
>> Maybe one of the following would be simple/general enough to work:
>>
>>   * Have each GUI startup script declare a variable, e.g. "gui_startup",
>>     which /etc/rc reads to determine whether to disable its startup if
>>     $boot_console is set.
>>   * Have an rc.conf(5) variable "gui_startup_scripts" which holds a list
>>     of startup scripts to not execute if $boot_console is set.
>>   * Have each GUI startup script REQUIRE (i.e. rcorder(8))
>>     "gui_start_check" which fails if $boot_console is set.
>>
>> GUI desktop port maintainers would have to modify their respective ports
>> to implement option 1 & 3; the user would have to add her desktop to
>> /etc/rc.conf for option 2.  I'd implement the guts.
>>
>> Other suggestions welcome.
>>
>> https://github.com/ScoobiFreeBSD/freebsd/commit/2376fc13627db10a65bcab9d9091cbd8ff049e87
>> https://github.com/ScoobiFreeBSD/freebsd/commit/2376fc13627db10a65bcab9d9091cbd8ff049e87.patch
>>
> I think I prefer the 3rd option, having a dependant service that is
> controlled by the variable from the boot loader. This minimizes the
> changes to each port to just a single word added to the metadata.
>
> If the ports people want to decide which method they prefer, I would be
> happy to shepherd the changes to the boot loader / menu itself.
The 3rd option turned out to be ridiculously simple using rcorder(8)'s
KEYWORD tag and /etc/rc's skipping of certain scripts.

    [ajenkins at ajenkins-hplaptop /usr/src]$ git diff 'HEAD^!'
    diff --git a/etc/rc b/etc/rc
    index 576ddf9..33ff6b2 100644
    --- a/etc/rc
    +++ b/etc/rc
    @@ -84,6 +84,12 @@ if [ `/sbin/sysctl -n security.jail.jailed` -eq 1
    ]; then
            fi
     fi
     
    +# If boot_console is enabled from loader(8), skip all rc.d scripts that
    +# are marked with KEYWORD "gui".
    +if [ "$(kenv boot_console 2>/dev/null)" = "YES" ]; then
    +       skip="${skip} -s gui"
    +fi
    +
     # If the firstboot sentinel doesn't exist, we want to skip
    firstboot scripts.
     if ! [ -e ${firstboot_sentinel} ]; then
            skip_firstboot="-s firstboot"


Now all GUI port maintainers have to do is add "gui" to the KEYWORD tag
in their rc.d scripts.

    [ajenkins at ajenkins-hplaptop /usr/ports]$ git diff
    diff --git a/x11/kde4-workspace/files/kdm4.in
    b/x11/kde4-workspace/files/kdm4.in
    index 278ff62..6bd96cf 100644
    --- a/x11/kde4-workspace/files/kdm4.in
    +++ b/x11/kde4-workspace/files/kdm4.in
    @@ -4,7 +4,7 @@
     #
     # PROVIDE: kdm4
     # REQUIRE: LOGIN cleanvar moused syscons dbus hald
    -# KEYWORD: shutdown
    +# KEYWORD: shutdown gui
     #
     # Add the following to /etc/rc.conf to start KDM at boot time:
     #

Now just need to sort out the wording of the option.

Anthony