From 4401925c822e2f7e927bad4c16e4a08ac6a18d9a Mon Sep 17 00:00:00 2001

From: Michal Soltys <soltys@ziu.info>

Date: Mon, 26 Dec 2011 14:29:15 +0800

Subject: [PATCH] Add job control support to emergency shell

Option --ctty will optionally add setsid binary to dracut's image.

During runtime, if rd.ctty is set and is a character device,

emergency shells will be spawned with job control.

in case no ctty was provided, shell was spawned without caring about

/dev/console. Also, the ctty is more opportunistic. If the image was

generated with --ctty, we will fallback to /dev/tty1 if rc.ctty is

invalid or missing. Otherwise we spawn standard shell on /dev/console

[dyoung@redhat.com: Rebased to usrmove branch]

Signed-off-by: Michal Soltys <soltys@ziu.info>

Signed-off-by: Dave Young <dyoung@redhat.com>

---

 dracut                           |    3 ++-

 dracut.8.xml                     |    9 +++++++++

 dracut.cmdline.7.xml             |   14 ++++++++++++++

 modules.d/99base/init            |   12 ++++++++++--

 modules.d/99base/module-setup.sh |    1 +

 modules.d/99shutdown/shutdown    |   12 ++++++++++--

 6 files changed, 46 insertions(+), 5 deletions(-)

diff --git a/dracut b/dracut

index 8c24e7b..3c21561 100755

--- a/dracut

+++ b/dracut

@@ -232,6 +232,7 @@ while (($# > 0)); do

         --nolvmconf)   lvmconf_l="no";;

         --debug)       debug="yes";;

         --profile)     profile="yes";;

+        --ctty)        cttyhack="yes";;

         -v|--verbose)  ((verbosity_mod_l++));;

         -q|--quiet)    ((verbosity_mod_l--));;

         -l|--local)    allowlocal="yes" ;;

@@ -585,7 +586,7 @@ done

 export initdir dracutbasedir dracutmodules drivers \

     fw_dir drivers_dir debug no_kernel kernel_only \

     add_drivers mdadmconf lvmconf filesystems \

-    use_fstab libdir usrlibdir fscks nofscks \

+    use_fstab libdir usrlibdir fscks nofscks cttyhack \

     stdloglvl sysloglvl fileloglvl kmsgloglvl logfile \

     debug host_fs_types host_devs

diff --git a/dracut.8.xml b/dracut.8.xml

index 221ad2e..955d4d2 100644

--- a/dracut.8.xml

+++ b/dracut.8.xml

@@ -297,6 +297,15 @@ include in the generic initramfs. This parameter can be specified multiple times

         </varlistentry>

         <varlistentry>

           <term>

+            <option>--ctty</option>

+          </term>

+          <listitem>

+            <para>if possible, try to spawn an emergency shell on a terminal

+              with job control</para>

+          </listitem>

+        </varlistentry>

+        <varlistentry>

+          <term>

             <option>-h</option>

           </term>

           <term>

diff --git a/dracut.cmdline.7.xml b/dracut.cmdline.7.xml

index 74e617c..0fa4762 100644

--- a/dracut.cmdline.7.xml

+++ b/dracut.cmdline.7.xml

@@ -109,6 +109,20 @@ This parameter can be specified multiple times.</para>

 	    <para>force loading kernel module <drivername> after all automatic loading modules have been loaded. This parameter can be specified multiple times.</para>

           </listitem>

         </varlistentry>

+        <varlistentry>

+          <term>

+            <envar>rd.ctty=<replaceable><terminal></replaceable></envar>

+          </term>

+          <listitem>

+            <para>

+              if the dracut image was generated with --ctty option, try to

+              spawn an emergency shell on the specified terminal; if

+              <envar>rd.ctty</envar> is specified without a value or not

+              provided at all, the default is /dev/tty1. The '/dev' prefix

+              can be omitted.

+            </para>

+          </listitem>

+        </varlistentry>

       </variablelist>

     </refsect2>

     <refsect2 id="dracut-kernel-debug">

diff --git a/modules.d/99base/init b/modules.d/99base/init

index 1e54449..33a7379 100755

--- a/modules.d/99base/init

+++ b/modules.d/99base/init

@@ -40,6 +40,7 @@ wait_for_loginit()

 emergency_shell()

 {

+    local _ctty

     set +e

     if [ "$1" = "-n" ]; then

         _rdshell_name=$2

@@ -57,8 +58,15 @@ emergency_shell()

         echo "Dropping to debug shell."

         echo

         export PS1="$_rdshell_name:\${PWD}# "

-        [ -e /.profile ] || echo "exec 0<>/dev/console 1<>/dev/console 2<>/dev/console" > /.profile

-        sh -i -l

+        [ -e /.profile ] || >/.profile

+        _ctty=/dev/console

+        if type setsid >/dev/null 2>&1; then

+            _ctty="$(getarg rd.ctty=)" && _ctty="/dev/${_ctty##*/}"

+            [ -c "$_ctty" ] || _ctty=/dev/tty1

+            setsid sh -i -l 0<$_ctty 1>$_ctty 2>&1

+        else

+            sh -i -l 0<$_ctty 1>$_ctty 2>&1

+        fi

     else

         warn "Boot has failed. To debug this issue add \"rdshell\" to the kernel command line."

         # cause a kernel panic

diff --git a/modules.d/99base/module-setup.sh b/modules.d/99base/module-setup.sh

index f6c1209..03058b1 100755

--- a/modules.d/99base/module-setup.sh

+++ b/modules.d/99base/module-setup.sh

@@ -16,6 +16,7 @@ install() {

     dracut_install mount mknod mkdir modprobe pidof sleep chroot \

         sed ls flock cp mv dmesg rm ln rmmod mkfifo umount readlink

     dracut_install -o less

+    [[ $cttyhack = yes ]] && dracut_install -o setsid

     if [ ! -e "${initdir}/bin/sh" ]; then

         dracut_install bash

         (ln -s bash "${initdir}/bin/sh" || :)

diff --git a/modules.d/99shutdown/shutdown b/modules.d/99shutdown/shutdown

index a31a95d..21bb37f 100755

--- a/modules.d/99shutdown/shutdown

+++ b/modules.d/99shutdown/shutdown

@@ -13,6 +13,7 @@ export TERM=linux

 emergency_shell()

 {

+    local _ctty

     set +e

     if [ "$1" = "-n" ]; then

         _rdshell_name=$2

@@ -29,8 +30,15 @@ emergency_shell()

         echo "Dropping to debug shell."

         echo

         export PS1="$_rdshell_name:\${PWD}# "

-        [ -e /.profile ] || echo "exec 0<>/dev/console 1<>/dev/console 2<>/dev/console" > /.profile

-        sh -i -l

+        [ -e /.profile ] || >/.profile

+        _ctty=/dev/console

+        if type setsid >/dev/null 2>&1; then

+            _ctty="$(getarg rd.ctty=)" && _ctty="/dev/${_ctty##*/}"

+            [ -c "$_ctty" ] || _ctty=/dev/tty1

+            setsid sh -i -l 0<$_ctty 1>$_ctty 2>&1

+        else

+            sh -i -l 0<$_ctty 1>$_ctty 2>&1

+        fi

     else

         exec /lib/systemd/systemd-shutdown "$@"

         warn "Shutdown has failed. To debug this issue add \"rdshell\" to the kernel command line."