David Dillow wrote:
/sbin/netroot is a jumping off point to allow various network
root devices to share infrastructure. It will loop over scriptlets
in the netroot handler, looking for a handler to run for this type
of netroot. Handlers can do choose to act based on command line
options to the kernel, or via DHCP options received on this interface.
They should massage root= into a form suitable for their handler.
Signed-off-by: David Dillow <dave@xxxxxxxxxxxxxx>
---
dracut | 2 +-
modules.d/40network/60-net.rules | 1 +
modules.d/40network/dhcp-fallback.sh | 14 +++++++++
modules.d/40network/ifup | 8 ++--
modules.d/40network/install | 2 +
modules.d/40network/netroot | 52 ++++++++++++++++++++++++++++++++++
modules.d/99base/init | 11 ++++++-
7 files changed, 84 insertions(+), 6 deletions(-)
create mode 100755 modules.d/40network/dhcp-fallback.sh
create mode 100755 modules.d/40network/netroot
diff --git a/dracut b/dracut
index 84c194e..e5e7ecd 100755
--- a/dracut
+++ b/dracut
@@ -96,7 +96,7 @@ if [[ -f $outfile && ! $force ]]; then
exit 1
fi
-hookdirs="cmdline pre-udev pre-mount pre-pivot mount emergency"
+hookdirs="cmdline pre-udev netroot pre-mount pre-pivot mount emergency"
readonly initdir=$(mktemp -d -t initramfs.XXXXXX)
trap 'rm -rf "$initdir"' 0 # clean up after ourselves no matter how we die.
diff --git a/modules.d/40network/60-net.rules b/modules.d/40network/60-net.rules
index 4b030c3..6c79508 100644
--- a/modules.d/40network/60-net.rules
+++ b/modules.d/40network/60-net.rules
@@ -1 +1,2 @@
ACTION=="add", SUBSYSTEM=="net", RUN+="/sbin/ifup $env{INTERFACE}"
+ACTION=="online", SUBSYSTEM=="net", RUN+="/sbin/netroot $env{INTERFACE}"
diff --git a/modules.d/40network/dhcp-fallback.sh b/modules.d/40network/dhcp-fallback.sh
new file mode 100755
index 0000000..1f4ec0c
--- /dev/null
+++ b/modules.d/40network/dhcp-fallback.sh
@@ -0,0 +1,14 @@
+# We should go last, and default the root if needed
+
+if [ -z "$root" ]; then
+ root=dhcp
+fi
Is this really necessary? I mean if no root option is supplied, we don't
really know if dhcp is really desired or the default /dev/sda1 fallback
should be used.
I'd suggest to only ever do netroot if the user explicitely requests it.
This would include disabling all network related udev scripts if we
don't want netroot.
+
+if [ "$root" = "dhcp" -a -z "$netroot" ]; then
+ rootok=1
+ netroot=dhcp
+fi
+
+if [ "${netroot+set}" = "set" ]; then
+ eval "echo netroot='$netroot'" > /tmp/netroot.info
+fi
diff --git a/modules.d/40network/ifup b/modules.d/40network/ifup
index ee4bc4a..981a207 100755
--- a/modules.d/40network/ifup
+++ b/modules.d/40network/ifup
@@ -12,8 +12,10 @@ getarg rdnetdebug && {
netif=$1
-# bail immediatly if the interface is already up
+# bail immediately if the interface is already up
+# or we don't need the network
[ -f "/tmp/net.$netif.up" ] && exit 0
+[ ! -f /tmp/netroot.info ] && exit 0
# loopback is always handled the same way
[ "$netif" = "lo" ] && {
@@ -93,10 +95,8 @@ ip_to_var() {
[ -n "$autoconf" ] || autoconf=off
}
-root=$(getarg root)
ip=$(getarg ip)
-
-if [ "$root" = "dhcp" -a -z "$ip" ]; then
Hmmm... Weird configuration: What do we do if root=dhcp and the ip
options contain's non-dhcp related stuff? (Never thought of that before)
+if [ -z "$ip" ]; then
do_dhcp;
else
# spin through the kernel command line, looking for ip= lines
diff --git a/modules.d/40network/install b/modules.d/40network/install
index d9ec7f0..3112494 100755
--- a/modules.d/40network/install
+++ b/modules.d/40network/install
@@ -2,8 +2,10 @@
dracut_install ip dhclient hostname
instmods =net
inst "$moddir/ifup" "/sbin/ifup"
+inst "$moddir/netroot" "/sbin/netroot"
inst "$moddir/dhclient-script" "/sbin/dhclient-script"
instmods =networking ecb arc4
inst_rules "$moddir/60-net.rules"
+inst_hook cmdline 99 "$moddir/dhcp-fallback.sh"
inst_hook pre-pivot 10 "$moddir/kill-dhclient.sh"
mkdir -p "${initdir}/var/run"
diff --git a/modules.d/40network/netroot b/modules.d/40network/netroot
new file mode 100755
index 0000000..3d03e72
--- /dev/null
+++ b/modules.d/40network/netroot
@@ -0,0 +1,52 @@
+#!/bin/sh
+
+. /lib/dracut-lib
+
+getarg rdnetdebug && {
+ exec >/tmp/netroot.$1.$$.out
+ exec 2>>/tmp/netroot.$1.$$.out
+ set -x
+}
+
+# Only try to configure from one network interface at a time
+#
+[ "$NETROOT_LOCKED" ] || {
+ NETROOT_LOCKED=true
+ export NETROOT_LOCKED
+ exec flock -xo /tmp/netroot.lock -c "$0 $*"
+ exit 1
+}
+
+netif=$1
+
+# If we've already found a root, or we don't have the info we need,
+# then no point in looking further
+#
+[ -e /tmp/netroot.done ] && exit 0
+[ -s /tmp/netroot.info -a -s /tmp/root.info ] || exit 0
+
+# Pick up our config from the command line; we may already know the
+# handler to run
+#
+. /tmp/root.info
+. /tmp/netroot.info
+[ -e /tmp/net.$netif.dhcpopts ] && . /tmp/net.$netif.dhcpopts
+
+# Now, let the installed network root handlers figure this out
+#
+source_all netroot
+
+# If we didn't get a handler set, then we're done
+#
+if [ -z "$handler" ]; then
+ # XXX informative error message?
+ exit 0
+fi
+
+# Run the handler; don't store the root, it may change from device to device
+# XXX other variables to export?
+export NEWROOT
+if $handler $netif $root; then
+ >/tmp/netroot.done
+fi
+exit 0
Question 1: Is it really necessary to have each handler implements it's
own mount-call? I don't know about iSCSI but isn't it usually just a
matter of setting fstype, options and source? I think this could be
generalized.
Question 2: How do plan to loop over mount-scripts? As you described if
might be desirable to retry mounting if the server is overloaded. I see
a few problems there if we loop inside netboot/handler-scripts: We could
be trying to mount on the wrong interface.
diff --git a/modules.d/99base/init b/modules.d/99base/init
index 73e96fd..b4fce6a 100755
--- a/modules.d/99base/init
+++ b/modules.d/99base/init
@@ -47,12 +47,21 @@ fi
if [ -z "${root%%error:*}" ]; then
case "${root%%:*}" in
- '') echo "FATAL: no root= option specified" ;;
+ '') echo "FATAL: no root= option specified, and no network support" ;;
error) echo "FATAL: ${root#error:}" ;;
esac
emergency_shell
fi
+# Network root scripts may need updated root= options,
+# so deposit them where they can see them (udev purges the env)
+{
+ echo "root='$root'"
+ echo "rflags='$rflags'"
+ echo "fstype='$fstype'"
+ echo "NEWROOT='$NEWROOT'"
+} > /tmp/root.info
+
# pre-udev scripts run before udev starts, and are run only once.
getarg 'rdbreak=pre-udev' && emergency_shell
source_all pre-udev
--
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