[PATCH] allow ifup bring up network mannually even without netroot

[PATCH] allow ifup bring up network mannually even without netroot

[Dave Young]

sometimes we need bring up network even without netroot

Here implement this by adding one param to ifup script, user can use:
/sbin/ifup $netif -m; to bring up eth0, note currently ifup will see
anything in param $2 as same.

`ifup eth0 -m` will create /tmp/net.eth0.mannual stamp file,
later dhclient-script can check this and pass $2 to netroot,
then netroot script will bring eth0 up

Signed-off-by: Dave Young <dyoung-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
---
 modules.d/40network/dhclient-script |    7 ++
 modules.d/40network/ifup            |   17 +++++--
 modules.d/40network/netroot         |   85 +++++++++++++++++++-----------------
 3 files changed, 67 insertions(+), 42 deletions(-)

Index: dracut/modules.d/40network/dhclient-script
===================================================================
--- dracut.orig/modules.d/40network/dhclient-script
+++ dracut/modules.d/40network/dhclient-script
@@ -74,7 +74,12 @@ case $reason in
             echo "$line"
         done >/tmp/dhclient.$netif.dhcpopts
         echo online > /sys/class/net/$netif/uevent
-        initqueue --onetime --name netroot-$netif netroot $netif
+        if [ -e /tmp/net.$netif.mannual ]; then
+            /sbin/netroot $netif -m
+            rm -f /tmp/net.$netif.mannual
+        else
+            initqueue --onetime --name netroot-$netif netroot $netif
+        fi
         ;;
     *) echo "dhcp: $reason";;
 esac
Index: dracut/modules.d/40network/ifup
===================================================================
--- dracut.orig/modules.d/40network/ifup
+++ dracut/modules.d/40network/ifup
@@ -5,6 +5,8 @@
 # We don't need to check for ip= errors here, that is handled by the
 # cmdline parser script
 #
+# without $2 means this is for real netroot case
+# or it is for mannually bring up network ie. for kdump scp vmcore
 PATH=/usr/sbin:/usr/bin:/sbin:/bin
 
 type getarg >/dev/null 2>&1 || . /lib/dracut-lib.sh
@@ -50,7 +52,11 @@ do_ipv6auto() {
 
 
     echo online > /sys/class/net/$netif/uevent
-    initqueue --onetime --name netroot-$netif netroot $netif
+    if [ -z "$2" ]; then
+        initqueue --onetime --name netroot-$netif netroot $netif
+    else
+        /sbin/netroot $netif -m
+    fi
 }
 
 # Handle static ip configuration
@@ -77,7 +83,11 @@ do_static() {
     fi >> /tmp/net.$netif.resolv.conf
 
     echo online > /sys/class/net/$netif/uevent
-    initqueue --onetime --name netroot-$netif netroot $netif
+    if [ -z "$2" ]; then
+        initqueue --onetime --name netroot-$netif netroot $netif
+    else
+        /sbin/netroot $netif -m
+    fi
 }
 
 export PS4="ifup.$1.$$ + "
@@ -117,7 +127,8 @@ fi
 [ -f "/tmp/net.$netif.up" ] && exit 0
 [ -f "/tmp/root.info" ] || exit 0
 . /tmp/root.info
-[ -z "$netroot" ] && exit 0
+[ -z "$netroot" ] && [ -z $2 ] && exit 0
+[ -n "$2" ] && >/tmp/net.$netif.mannual
 
 # loopback is always handled the same way
 if [ "$netif" = "lo" ] ; then
Index: dracut/modules.d/40network/netroot
===================================================================
--- dracut.orig/modules.d/40network/netroot
+++ dracut/modules.d/40network/netroot
@@ -12,12 +12,16 @@ type getarg >/dev/null 2>&1 || . /lib/dr
 # Huh? No interface config?
 [ ! -e /tmp/net.$1.up ] && exit 1
 
-# There's no sense in doing something if no (net)root info is available
+# [ ! -z $2 ] means this is for mannually bringing up network
+# instead of real netroot; If It's called without $2, then there's
+# no sense in doing something if no (net)root info is available
 # or root is already there
-[ -e /tmp/root.info ] || exit 1
-. /tmp/root.info
-[ -d $NEWROOT/proc ] && exit 0
-[ -z "$netroot" ] && exit 1
+if [ -z "$2" ]; then
+    [ -e /tmp/root.info ] || exit 1
+    . /tmp/root.info
+    [ -d $NEWROOT/proc ] && exit 0
+    [ -z "$netroot" ] && exit 1
+fi
 
 # Let's see if we have to wait for other interfaces
 # Note: exit works just fine, since the last interface to be
@@ -32,42 +36,44 @@ netif=$1
 [ -e "/tmp/net.bootdev" ] && read netif < /tmp/net.bootdev
 
 # Figure out the handler for root=dhcp by recalling all netroot cmdline
-# handlers
-if [ "$netroot" = "dhcp" ] || [ "$netroot" = "dhcp6" ] ; then
-    # Unset root so we can check later
-    unset root
-
-    # Load dhcp options
-    [ -e /tmp/dhclient.$netif.dhcpopts ] && . /tmp/dhclient.$netif.dhcpopts
-
-    # If we have a specific bootdev with no dhcpoptions or empty root-path,
-    # we die. Otherwise we just warn
-    if [ -z "$new_root_path" ] ; then
-        [ -n "$BOOTDEV" ] && die "No dhcp root-path received for '$BOOTDEV'"
-        warn "No dhcp root-path received for '$BOOTDEV' trying other interfaces if available"
-        exit 1
-    fi
+# handlers when this is not called from mannually network bringing up.
+if [ -z "$2" ]; then
+    if [ "$netroot" = "dhcp" ] || [ "$netroot" = "dhcp6" ] ; then
+        # Unset root so we can check later
+        unset root
+
+        # Load dhcp options
+        [ -e /tmp/dhclient.$netif.dhcpopts ] && . /tmp/dhclient.$netif.dhcpopts
+
+        # If we have a specific bootdev with no dhcpoptions or empty root-path,
+        # we die. Otherwise we just warn
+        if [ -z "$new_root_path" ] ; then
+            [ -n "$BOOTDEV" ] && die "No dhcp root-path received for '$BOOTDEV'"
+            warn "No dhcp root-path received for '$BOOTDEV' trying other interfaces if available"
+            exit 1
+        fi
 
-    # Set netroot to new_root_path, so cmdline parsers don't call
-    netroot=$new_root_path
+        # Set netroot to new_root_path, so cmdline parsers don't call
+        netroot=$new_root_path
 
-    # FIXME!
-    for f in $hookdir/cmdline/90*.sh; do
-        [ -f "$f" ] && . "$f";
-    done
-else
-    rootok="1"
-fi
+        # FIXME!
+        for f in $hookdir/cmdline/90*.sh; do
+            [ -f "$f" ] && . "$f";
+        done
+    else
+        rootok="1"
+    fi
 
-# Check: do we really know how to handle (net)root?
-[ -z "$root" ] && die "No or empty root= argument"
-[ -z "$rootok" ] && die "Don't know how to handle 'root=$root'"
-
-handler=${netroot%%:*}
-handler=${handler%%4}
-handler=$(command -v ${handler}root)
-if [ -z "$netroot" ] || [ ! -e "$handler" ] ; then
-    die "No handler for netroot type '$netroot'"
+    # Check: do we really know how to handle (net)root?
+    [ -z "$root" ] && die "No or empty root= argument"
+    [ -z "$rootok" ] && die "Don't know how to handle 'root=$root'"
+
+    handler=${netroot%%:*}
+    handler=${handler%%4}
+    handler=$(command -v ${handler}root)
+    if [ -z "$netroot" ] || [ ! -e "$handler" ] ; then
+        die "No handler for netroot type '$netroot'"
+    fi
 fi
 
 # We're here, so we can assume that upping interfaces is now ok
@@ -122,6 +128,9 @@ if [ -n "$dest" ] && ! arping -q -f -w 6
     dinfo "Resolving $dest via ARP on $netif failed"
 fi
 
+# exit in case mannually bring up network
+[ -n $2 ] && exit 0
+
 # Source netroot hooks before we start the handler
 source_all netroot
 

Re: [PATCH] allow ifup bring up network mannually even without netroot

[David Dillow]

On Thu, 2011-12-29 at 11:13 +0800, Dave Young wrote:
> sometimes we need bring up network even without netroot
> 
> Here implement this by adding one param to ifup script, user can use:
> /sbin/ifup $netif -m; to bring up eth0, note currently ifup will see
> anything in param $2 as same.
> 
> `ifup eth0 -m` will create /tmp/net.eth0.mannual stamp file,
> later dhclient-script can check this and pass $2 to netroot,
> then netroot script will bring eth0 up

'Manual' is misspelled throughout the patch, and your commit message is
a bit broken -- you say '/sbin/ifup $netif -m' will bring up eth0. You
put the command line that actually would in the next paragraph.

What's the use case? I'm sure there probably is one, but it's better to
be specific in the commit message when giving an example. I'm assuming
this is for your kdump work?


> --- dracut.orig/modules.d/40network/dhclient-script
> +++ dracut/modules.d/40network/dhclient-script
> @@ -74,7 +74,12 @@ case $reason in
>              echo "$line"
>          done >/tmp/dhclient.$netif.dhcpopts
>          echo online > /sys/class/net/$netif/uevent
> -        initqueue --onetime --name netroot-$netif netroot $netif
> +        if [ -e /tmp/net.$netif.mannual ]; then
> +            /sbin/netroot $netif -m
> +            rm -f /tmp/net.$netif.mannual
> +        else
> +            initqueue --onetime --name netroot-$netif netroot $netif
> +        fi

And if we want to use kdump with NFS root?

I think it would be cleaner to add either conditionally add netroot to
the initqueue only when there is actually a netroot used, or
make /sbin/netroot not care... it currently exits with a nonzero value
if /tmp/root.info isn't there, or $netroot is empty. I assume that
causes problems elsewhere -- I haven't kept up with dracut for a while
-- but perhaps not and it is safe to just always call it.

> --- dracut.orig/modules.d/40network/ifup
> +++ dracut/modules.d/40network/ifup

> @@ -50,7 +52,11 @@ do_ipv6auto() {
>  
> 
>      echo online > /sys/class/net/$netif/uevent
> -    initqueue --onetime --name netroot-$netif netroot $netif
> +    if [ -z "$2" ]; then
> +        initqueue --onetime --name netroot-$netif netroot $netif
> +    else
> +        /sbin/netroot $netif -m
> +    fi
>  }

Same comment here, with the added bonus that "$2" will reference the
function's arguments, not the scripts, so you'll always do the initqueue
call. 

Why are you wanting to run netroot immediately if you aren't using a
network root? 

If it's just to copy the configuration over when you have a kdump, is it
going to hurt things to not copy in that case? Do the network scripts in
the real root care? They have to handle the case when you don't have a
kdump anyway -- assuming you don't bring up the network in dracut unless
you have a dump push.

If they really do care, then perhaps consider splitting out the copying
of the config to a separate step that can be shared, rather than making
things uglier than they already are. It'd probably be a good cleanup on
it's own merits.

Dave

Re: [PATCH] allow ifup bring up network mannually even without netroot

[Dave Young]

On 12/29/2011 05:05 PM, David Dillow wrote:

> On Thu, 2011-12-29 at 11:13 +0800, Dave Young wrote:
>> sometimes we need bring up network even without netroot
>>
>> Here implement this by adding one param to ifup script, user can use:
>> /sbin/ifup $netif -m; to bring up eth0, note currently ifup will see
>> anything in param $2 as same.
>>
>> `ifup eth0 -m` will create /tmp/net.eth0.mannual stamp file,
>> later dhclient-script can check this and pass $2 to netroot,
>> then netroot script will bring eth0 up
> 
> 'Manual' is misspelled throughout the patch, and your commit message is
> a bit broken -- you say '/sbin/ifup $netif -m' will bring up eth0. You
> put the command line that actually would in the next paragraph.


Thanks for comments.
Will check and fix the spelling.
For broken commit message you means 's/$netif/eth0' ? will fix

> 
> What's the use case? I'm sure there probably is one, but it's better to
> be specific in the commit message when giving an example. I'm assuming
> this is for your kdump work?


Yes, kdump will need scp vmcore to remote machine which need net up
without netroot
Also will add to v2 patch description

> 
> 
>> --- dracut.orig/modules.d/40network/dhclient-script
>> +++ dracut/modules.d/40network/dhclient-script
>> @@ -74,7 +74,12 @@ case $reason in
>>              echo "$line"
>>          done >/tmp/dhclient.$netif.dhcpopts
>>          echo online > /sys/class/net/$netif/uevent
>> -        initqueue --onetime --name netroot-$netif netroot $netif
>> +        if [ -e /tmp/net.$netif.mannual ]; then
>> +            /sbin/netroot $netif -m
>> +            rm -f /tmp/net.$netif.mannual
>> +        else
>> +            initqueue --onetime --name netroot-$netif netroot $netif
>> +        fi
> 
> And if we want to use kdump with NFS root?


If nfsroot is already mounted as sysroot, ifup eth0 -m will return as
nop; If ifup eth0 -m run firstly then the shared codes will pass-through
and still will run netroot specific code.

> 
> I think it would be cleaner to add either conditionally add netroot to
> the initqueue only when there is actually a netroot used, or
> make /sbin/netroot not care... it currently exits with a nonzero value
> if /tmp/root.info isn't there, or $netroot is empty. I assume that
> causes problems elsewhere -- I haven't kept up with dracut for a while
> -- but perhaps not and it is safe to just always call it.


I'm not sure I fully understand your option. can you elaborate more detail?

> 
>> --- dracut.orig/modules.d/40network/ifup
>> +++ dracut/modules.d/40network/ifup
> 
>> @@ -50,7 +52,11 @@ do_ipv6auto() {
>>  
>>
>>      echo online > /sys/class/net/$netif/uevent
>> -    initqueue --onetime --name netroot-$netif netroot $netif
>> +    if [ -z "$2" ]; then
>> +        initqueue --onetime --name netroot-$netif netroot $netif
>> +    else
>> +        /sbin/netroot $netif -m
>> +    fi
>>  }
> 
> Same comment here, with the added bonus that "$2" will reference the
> function's arguments, not the scripts, so you'll always do the initqueue
> call. 


Good catch, will fix

> 
> Why are you wanting to run netroot immediately if you aren't using a
> network root? 


I want it behave like a manual operation.

> 
> If it's just to copy the configuration over when you have a kdump, is it
> going to hurt things to not copy in that case? Do the network scripts in
> the real root care? They have to handle the case when you don't have a
> kdump anyway -- assuming you don't bring up the network in dracut unless
> you have a dump push.


we need to scp to nics other than nfs root nic also.

> 
> If they really do care, then perhaps consider splitting out the copying
> of the config to a separate step that can be shared, rather than making
> things uglier than they already are. It'd probably be a good cleanup on
> it's own merits.

>

I firstly tried to split the code and isolate some code out, but finally
find it become more complex become current dracut is fully oriented to
rootfs mounting...

> Dave
> 
> 
> 
> 



-- 
Thanks
Dave