Bug 443554 – Add "s" option to boot single user mode from grub command line

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Bug 443554 - Add "s" option to boot single user mode from grub command line

Summary:	Add "s" option to boot single user mode from grub command line

Status:	CLOSED RAWHIDE

Aliases:	None

Product:	Fedora
Classification:	Fedora
Component:	event-compat-sysv (Show other bugs)
Sub Component:
Version:	rawhide
Hardware:	All Linux

Priority	low Severity low
Target Milestone:	---
Target Release:	---
Assigned To:	Casey Dahlin
QA Contact:	Fedora Extras Quality Assurance
Docs Contact:

URL:
Whiteboard:
Keywords:

Depends On:
Blocks:
	Show dependency tree / graph

Reported:	2008-04-22 03:36 EDT by CHIKAMA Masaki
Modified:	2014-06-18 04:46 EDT (History)
CC List:	2 users (show)

See Also:
Fixed In Version:
Doc Type:	Bug Fix
Doc Text:
Story Points:	---
Clone Of:
Environment:
Last Closed:	2008-04-24 15:47:25 EDT
Type:	---
Regression:	---
Mount Type:	---
Documentation:	---
CRM:
Verified Versions:
Category:	---
oVirt Team:	---
RHEL 7.3 requirements from Atomic Host:

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Add an attachment (proposed patch, testcase, etc.)

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Description CHIKAMA Masaki 2008-04-22 03:36:58 EDT

Description of problem:
 Historycally we can boot with single user mode from grub command line
adding "s". But after changing to upstart, only "-s", "single" and "S" are
allowed. 

Version-Release number of selected component (if applicable):
 event-compat-sysv-0.3.9-13.fc9.noarch

How reproducible:
 always when type "s"


Steps to Reproduce:
1. enter grub menu
2. append "s" to command line
3.
  
Actual results:
default runlevel (3 or 5)

Expected results:
single user mode (1)

Additional info:
 Here is a proposed patch.
--- /etc/event.d/rcS~   2008-04-05 00:49:20.000000000 +0900
+++ /etc/event.d/rcS    2008-04-22 16:32:45.000000000 +0900
@@ -20,7 +20,7 @@
        [ -z "$runlevel" ] && runlevel="3"
        for t in $(cat /proc/cmdline); do
                case $t in
-                       -s|single|S) runlevel="S" ;;
+                       -s|single|S|s) runlevel="S" ;;
                        [1-9])       runlevel="$t" ;;
                esac
        done

Comment 1 Bill Nottingham 2008-04-22 11:21:25 EDT

I'm not sure why 's' worked before. From the init manpage:

Init accepts the following flags:

       -s, S, single
            Single user mode boot. In this mode /etc/inittab is examined  and  the
            bootup rc scripts are usually run before the single user mode shell is
            started.

From the code:
                if (!strcmp(argv[f], "single") || !strcmp(argv[f], "-s"))
                        dfl_level = 'S';

So, I don't think 's' was ever really supported.

Comment 2 Bill Nottingham 2008-04-22 11:22:43 EDT

Aha, found it:

                if (dfl_level == 's') dfl_level = 'S';

Yay for undocumented features.

Comment 3 CHIKAMA Masaki 2008-04-22 11:34:11 EDT

Which man page you are referring ?

On F8, LANG=C man 8 init said

       Runlevel S or s bring the system to single user mode and do not require
       an /etc/inittab file.  In single user mode, a root shell is  opened  on
       /dev/console.

$ rpm -qf /usr/share/man/man8/init.8.gz
sysvinit-2.86-18

Comment 4 Bill Nottingham 2008-04-24 15:47:25 EDT

Will be in 0.3.9-14.

Comment 5 CHIKAMA Masaki 2008-04-24 23:49:03 EDT

Sorry. Please ignore Comment #3.

And thank you for adding undocumented feature.
I've been using this option for over 10 years.
It's so thanksfull to keep compatibility.

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