Re: [PATCH 1/7] allow ifup bring up network manually even without netroot

[Harald Hoyer <harald-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

Am 02.02.2012 08:59, schrieb Dave Young:
> For kdump we need scp vmcore to remote machine, the nic to be used is
> not limited to netroot one. we need a feature for manually bringing up
>  network interface. Also it is useful for emergency shell with
> ssh-client for recovery or test purpose
> 
> I implement this by adding one argument to ifup script, user can use
> `/sbin/ifup eth0 -m` to bring up eth0, note ifup will regard it a
> manual operation for the nic specified in 1st argument if there's
> the 2nd argument.
> 
> If same nic is used for netroot the 2nd argument will be ignored,
> in this case we will leave netroot bring up it automatically to
> avoid side effect. And in this case hooks such as kdump will need to
> execute after netroot mounted.
> 
> `ifup eth0 -m` will create /tmp/net.eth0.manualup stamp file,
> later dhclient-script can check this and pass $2 to netroot,
> then netroot script will bring eth0 up
> 
> Thanks for comments and suggestions from David Dillow.
> 
> Signed-off-by: Dave Young <dyoung-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> ---
>  modules.d/40network/dhclient-script |    8 ++
>  modules.d/40network/ifup            |   97 ++++++++++++++++++++----------------
>  modules.d/40network/netroot         |   86 ++++++++++++++++++-------------
>  3 files changed, 111 insertions(+), 80 deletions(-)
> 
> Index: dracut/modules.d/40network/dhclient-script
> ===================================================================
> --- dracut.orig/modules.d/40network/dhclient-script
> +++ dracut/modules.d/40network/dhclient-script
> @@ -76,7 +76,13 @@ 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.manualup ]; then
> +            /sbin/netroot $netif -m
> +            rm -f /tmp/net.$netif.manualup
> +        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
> @@ -5,9 +5,54 @@
>  # 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 manually 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
> +export PS4="ifup.$1.$$ + "
> +exec >>/run/initramfs/loginit.pipe 2>>/run/initramfs/loginit.pipe
> +type getarg >/dev/null 2>&1 || . /lib/dracut-lib.sh
> +
> +# Huh? No $1?
> +[ -z "$1" ] && exit 1
> +
> +# $netif reads easier than $1
> +netif=$1
> +
> +# enslave this interface to bond?
> +if [ -e /tmp/bond.info ]; then
> +    . /tmp/bond.info
> +    for slave in $bondslaves ; do
> +        if [ "$netif" = "$slave" ] ; then
> +            netif=$bondname
> +        fi
> +    done
> +fi
> +
> +# bridge this interface?
> +if [ -e /tmp/bridge.info ]; then
> +    . /tmp/bridge.info
> +    if [ "$netif" = "$ethname" ]; then
> +        if [ "$netif" = "$bondname" ] && [ -n "$DO_BOND_SETUP" ] ; then
> +            : # We need to really setup bond (recursive call)
> +        else
> +            netif="$bridgename"
> +        fi
> +    fi
> +fi
> +
> +# bail immediately if the interface is already up
> +# or we don't need the network
> +[ -f "/tmp/net.$netif.up" ] && exit 0
> +[ -f "/tmp/root.info" ] || exit 0
> +. /tmp/root.info
> +
> +# disable manual ifup while netroot is set for simplifying our logic
> +# in netroot case we prefer netroot to bringup $netif automaticlly
> +[ -n "$2" ] && [ -z "$netroot" ] && manualup="$2"
> +[ -z "$netroot" ] && [ -z "$manualup" ] && exit 0
> +[ -n "$manualup" ] && >/tmp/net.$netif.manualup
>  
>  # Run dhclient
>  do_dhcp() {
> @@ -50,7 +95,11 @@ do_ipv6auto() {
>  
>  
>      echo online > /sys/class/net/$netif/uevent
> -    initqueue --onetime --name netroot-$netif netroot $netif
> +    if [ -n "$manualup" ]; then
> +        /sbin/netroot $netif -m
> +    else
> +        initqueue --onetime --name netroot-$netif netroot $netif
> +    fi
>  }
>  
>  # Handle static ip configuration
> @@ -77,47 +126,12 @@ do_static() {
>      fi >> /tmp/net.$netif.resolv.conf
>  
>      echo online > /sys/class/net/$netif/uevent
> -    initqueue --onetime --name netroot-$netif netroot $netif
> -}
> -
> -export PS4="ifup.$1.$$ + "
> -exec >>/run/initramfs/loginit.pipe 2>>/run/initramfs/loginit.pipe
> -type getarg >/dev/null 2>&1 || . /lib/dracut-lib.sh
> -
> -# Huh? No $1?
> -[ -z "$1" ] && exit 1
> -
> -# $netif reads easier than $1
> -netif=$1
> -
> -# enslave this interface to bond?
> -if [ -e /tmp/bond.info ]; then
> -    . /tmp/bond.info
> -    for slave in $bondslaves ; do
> -        if [ "$netif" = "$slave" ] ; then
> -            netif=$bondname
> -        fi
> -    done
> -fi
> -
> -# bridge this interface?
> -if [ -e /tmp/bridge.info ]; then
> -    . /tmp/bridge.info
> -    if [ "$netif" = "$ethname" ]; then
> -        if [ "$netif" = "$bondname" ] && [ -n "$DO_BOND_SETUP" ] ; then
> -            : # We need to really setup bond (recursive call)
> -        else
> -            netif="$bridgename"
> -        fi
> +    if [ -n "$manualup" ]; then
> +        /sbin/netroot $netif -m
> +    else
> +        initqueue --onetime --name netroot-$netif netroot $netif
>      fi
> -fi
> -
> -# bail immediately if the interface is already up
> -# or we don't need the network
> -[ -f "/tmp/net.$netif.up" ] && exit 0
> -[ -f "/tmp/root.info" ] || exit 0
> -. /tmp/root.info
> -[ -z "$netroot" ] && exit 0
> +}
>  
>  # loopback is always handled the same way
>  if [ "$netif" = "lo" ] ; then
> @@ -228,5 +242,4 @@ for p in $(getargs ip=); do
>      esac
>      break
>  done
> -
>  exit 0
> Index: dracut/modules.d/40network/netroot
> ===================================================================
> --- dracut.orig/modules.d/40network/netroot
> +++ dracut/modules.d/40network/netroot
> @@ -3,7 +3,6 @@
>  # ex: ts=8 sw=4 sts=4 et filetype=sh
>  
>  PATH=/usr/sbin:/usr/bin:/sbin:/bin
> -
>  type getarg >/dev/null 2>&1 || . /lib/dracut-lib.sh
>  
>  # Huh? Empty $1?
> @@ -12,12 +11,16 @@ 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 manually 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
> +    [ -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
> @@ -31,43 +34,49 @@ done
>  netif=$1
>  [ -e "/tmp/net.bootdev" ] && read netif < /tmp/net.bootdev
>  
> +if [ -e /tmp/net.$netif.manualup ]; then
> +    rm -f /tmp/net.$netif.manualup
> +fi
> +
>  # Figure out the handler for root=dhcp by recalling all netroot cmdline
> -# handlers
> -if [ "$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 manually 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 +131,9 @@ if [ -n "$dest" ] && ! arping -q -f -w 6
>      dinfo "Resolving $dest via ARP on $netif failed"
>  fi
>  
> +# exit in case manually bring up network
> +[ -n "$2" ] && exit 0
> +
>  # Source netroot hooks before we start the handler
>  source_all $hookdir/netroot
>  
> --
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