Re: [PATCH v4] SLiRP support in runqemu

[Saul Wold <sgw@linux.intel.com>]

On 04/29/2013 11:42 PM, Andrei Dinu wrote:
> runqemu script now takes argument "slirp" in order to
> run networking on the qemu machine, without root privileges.
>
> changed the runqemu-internal script in order not to activate
> the tap devices if the option is set. Also trimmed the
> cleanup function so that after the image is closed, no
> tap releases warnings showed up.
>

Andrei,

You may have inadvertently dropped some of the newer code for locking to 
prevent some issues we saw on the auto builder, please review your patch 
and the locking code carefully.

Sau!

> [YOCTO #1474]
>
> Signed-off-by: Andrei Dinu <andrei.adrianx.dinu@intel.com>
> ---
>   scripts/runqemu          |    3 +
>   scripts/runqemu-internal |  220 ++++++++++++++++++++++++++--------------------
>   2 files changed, 130 insertions(+), 93 deletions(-)
>
> diff --git a/scripts/runqemu b/scripts/runqemu
> index 8ed1226..31deb6f 100755
> --- a/scripts/runqemu
> +++ b/scripts/runqemu
> @@ -173,6 +173,9 @@ while true; do
>               KVM_ENABLED="yes"
>               KVM_CAPABLE=`grep -q 'vmx\|svm' /proc/cpuinfo && echo 1`
>               ;;
> +        "slirp")
> +            SLIRP_ENABLED="yes"
> +            ;;
>           "publicvnc")
>               SCRIPT_QEMU_OPT="$SCRIPT_QEMU_OPT -vnc 0.0.0.0:0"
>               ;;
> diff --git a/scripts/runqemu-internal b/scripts/runqemu-internal
> index f11706d..644859c 100755
> --- a/scripts/runqemu-internal
> +++ b/scripts/runqemu-internal
> @@ -104,93 +104,111 @@ fi
>
>   NFSRUNNING="false"
>
> -acquire_lock() {
> -    lockfile=$1
> -    if [ -z "$lockfile" ]; then
> -        echo "Error: missing lockfile arg passed to acquire_lock()"
> -        return 1
> -    fi
> -
> -    touch $lockfile.lock
> -    exec 8>$lockfile.lock
> -    flock -n -x 8
> -    if [ $? -ne 0 ]; then
> -        exec 8>&-
> -        return 1

Looks like you are dropping some important locking bits here and other 
places below.

> +if [ "$SLIRP_ENABLED" = "yes" ]; then
> +    KERNEL_NETWORK_CMD=""
> +    QEMU_TAP_CMD=""
> +    if [ "$KVM_ACTIVE" = "yes" ]; then
> +        QEMU_NETWORK_CMD=""
> +        DROOT="/dev/vda"
> +        ROOTFS_OPTIONS="-drive file=$ROOTFS,if=virtio"
> +    else
> +        QEMU_NETWORK_CMD=""
> +        DROOT="/dev/hda"
> +        ROOTFS_OPTIONS="-hda $ROOTFS"
>       fi
> +else
> +    acquire_lock() {
> +        lockfile=$1
> +        if [ -z "$lockfile" ]; then
> +            echo "Error: missing lockfile arg passed to acquire_lock()"
> +            return 1
> +        fi
>
> -    return 0
> -}
> +        if [ -e "$lockfile.lock" ]; then
> +            # Check that the lockfile is not stale
> +            ps=`ps -eo pid | grep $(cat $lockfile.lock)`
> +            if [ -z "$ps" ]; then
> +                echo "WARNING: Stale lock file detected, deleting $lockfile.lock."
> +                rm -f $lockfile.lock
> +                echo $$ > $lockfile.lock
> +            else
> +                return 1
> +            fi
> +        else
> +            echo $$ > $lockfile.lock
> +        fi
>
> -release_lock() {
> -    lockfile=$1
> -    if [ -z "$lockfile" ]; then
> -        echo "Error: missing lockfile arg passed to release_lock()"
> -        return 1
> +        return 0
> +    }
> +    release_lock() {
> +        lockfile=$1
> +        if [ -z "$lockfile" ]; then
> +            echo "Error: missing lockfile arg passed to release_lock()"
> +            return 1
> +        fi
> +
> +        rm -f $lockfile.lock
> +    }
> +
> +    LOCKDIR="/tmp/qemu-tap-locks"
> +    if [ ! -d "$LOCKDIR" ]; then
> +        mkdir $LOCKDIR
> +        chmod 777 $LOCKDIR
>       fi
>
> -    rm -f $lockfile.lock
> -    exec  8>&-
> -}
> +    IFCONFIG=`which ifconfig 2> /dev/null`
> +    if [ -z "$IFCONFIG" ]; then
> +        IFCONFIG=/sbin/ifconfig
> +    fi
>
> -LOCKDIR="/tmp/qemu-tap-locks"
> -if [ ! -d "$LOCKDIR" ]; then
> -    mkdir $LOCKDIR
> -    chmod 777 $LOCKDIR
> -fi
and here

> +    if [ ! -x "$IFCONFIG" ]; then
> +          echo "$IFCONFIG cannot be executed"
> +          exit 1
> +    fi
>
> -IFCONFIG=`which ifconfig 2> /dev/null`
> -if [ -z "$IFCONFIG" ]; then
> -    IFCONFIG=/sbin/ifconfig
> -fi
> -if [ ! -x "$IFCONFIG" ]; then
> -       echo "$IFCONFIG cannot be executed"
> -       exit 1
> -fi
> +    POSSIBLE=`$IFCONFIG -a | grep '^tap' | awk '{print $1}' | sed s/://`
> +    TAP=""
> +    LOCKFILE=""
> +    for tap in $POSSIBLE; do
> +        LOCKFILE="$LOCKDIR/$tap"
> +        echo "Acquiring lockfile for $tap..."
> +        acquire_lock $LOCKFILE
> +        if [ $? -eq 0 ]; then
> +           TAP=$tap
> +           break
> +        fi
> +    done
> +
> +    if [ "$TAP" = "" ]; then
> +        if [ -e "$NOSUDO_FLAG" ]; then
> +            echo "Error: There are no available tap devices to use for networking,"
> +            echo "and I see $NOSUDO_FLAG exists, so I am not going to try creating"
> +            echo "a new one with sudo."
> +            exit 1
> +        fi
>
> -POSSIBLE=`$IFCONFIG -a | grep '^tap' | awk '{print $1}' | sed s/://`
> -TAP=""
> -LOCKFILE=""
> -for tap in $POSSIBLE; do
> -    LOCKFILE="$LOCKDIR/$tap"
> -    echo "Acquiring lockfile for $tap..."
> -    acquire_lock $LOCKFILE
> -    if [ $? -eq 0 ]; then
> -        TAP=$tap
> -        break
> -    fi
> -done
> -
> -if [ "$TAP" = "" ]; then
> -    if [ -e "$NOSUDO_FLAG" ]; then
> -        echo "Error: There are no available tap devices to use for networking,"
> -        echo "and I see $NOSUDO_FLAG exists, so I am not going to try creating"
> -        echo "a new one with sudo."
> -        exit 1
> -    fi
> -
> -    GROUPID=`id -g`
> -    USERID=`id -u`
> -    echo "Setting up tap interface under sudo"
> -    # Redirect stderr since we could see a LD_PRELOAD warning here if pseudo is loaded
> -    # but inactive. This looks scary but is harmless
> -    tap=`sudo $QEMUIFUP $USERID $GROUPID $OECORE_NATIVE_SYSROOT 2> /dev/null`
> -    if [ $? -ne 0 ]; then
> -        # Re-run standalone to see verbose errors
> -        sudo $QEMUIFUP $USERID $GROUPID $OECORE_NATIVE_SYSROOT
> -        return 1
> +        GROUPID=`id -g`
> +        USERID=`id -u`
> +        echo "Setting up tap interface under sudo"
> +        # Redirect stderr since we could see a LD_PRELOAD warning here if pseudo is loaded
> +        # but inactive. This looks scary but is harmless
> +        tap=`sudo $QEMUIFUP $USERID $GROUPID $OECORE_NATIVE_SYSROOT 2> /dev/null`
> +        if [ $? -ne 0 ]; then
> +            # Re-run standalone to see verbose errors
> +            sudo $QEMUIFUP $USERID $GROUPID $OECORE_NATIVE_SYSROOT
> +            return
> +        fi
> +        LOCKFILE="$LOCKDIR/$tap"
> +        echo "Acquiring lockfile for $tap..."
> +        acquire_lock $LOCKFILE
> +        if [ $? -eq 0 ]; then
> +            TAP=$tap
> +        fi
> +    else
> +        echo "Using preconfigured tap device '$TAP'"
>       fi
> -    LOCKFILE="$LOCKDIR/$tap"
> -    echo "Acquiring lockfile for $tap..."
> -    acquire_lock $LOCKFILE
> -    if [ $? -eq 0 ]; then
> -        TAP=$tap
> -    fi
> -else
> -    echo "Using preconfigured tap device '$TAP'"
> -fi
> -
> -cleanup() {
> +
> +    cleanup() {
>       if [ ! -e "$NOSUDO_FLAG" ]; then
>           # Redirect stderr since we could see a LD_PRELOAD warning here if pseudo is loaded
>           # but inactive. This looks scary but is harmless
> @@ -209,21 +227,33 @@ cleanup() {
>       stty sane
>   }
>
> -n0=$(echo $TAP | sed 's/tap//')
> -n1=$(($n0 * 2 + 1))
> -n2=$(($n1 + 1))
> -
> -KERNEL_NETWORK_CMD="ip=192.168.7.$n2::192.168.7.$n1:255.255.255.0"
> -QEMU_TAP_CMD="-net tap,vlan=0,ifname=$TAP,script=no,downscript=no"
> -if [ "$KVM_ACTIVE" = "yes" ]; then
> -    QEMU_NETWORK_CMD="-net nic,model=virtio $QEMU_TAP_CMD,vhost=on"
> -    DROOT="/dev/vda"
> -    ROOTFS_OPTIONS="-drive file=$ROOTFS,if=virtio"
> -else
> -    QEMU_NETWORK_CMD="-net nic,vlan=0 $QEMU_TAP_CMD"
> -    DROOT="/dev/hda"
> -    ROOTFS_OPTIONS="-hda $ROOTFS"
> +    n0=$(echo $TAP | sed 's/tap//')
> +    n1=$(($n0 * 2 + 1))
> +    n2=$(($n1 + 1))
> +    KERNEL_NETWORK_CMD="ip=192.168.7.$n2::192.168.7.$n1:255.255.255.0"
> +    QEMU_TAP_CMD="-net tap,vlan=0,ifname=$TAP,script=no,downscript=no"
> +
> +    if [ "$KVM_ACTIVE" = "yes" ]; then
> +        QEMU_NETWORK_CMD="-net nic,model=virtio $QEMU_TAP_CMD,vhost=on"
> +        DROOT="/dev/vda"
> +        ROOTFS_OPTIONS="-drive file=$ROOTFS,if=virtio"
> +    else
> +        QEMU_NETWORK_CMD="-net nic,vlan=0 $QEMU_TAP_CMD"
> +        DROOT="/dev/hda"
> +        ROOTFS_OPTIONS="-hda $ROOTFS"
> +    fi
>   fi
> +cleanup() {
> +
> +    if [ "$NFSRUNNING" = "true" ]; then
> +    echo "Shutting down the userspace NFS server..."
> +    echo "runqemu-export-rootfs stop $ROOTFS"
> +    runqemu-export-rootfs stop $ROOTFS
> +    fi
> +    # If QEMU crashes or somehow tty properties are not restored
> +    # after qemu exits, we need to run stty sane
> +    stty sane
> +}
>   KERNCMDLINE="mem=$QEMU_MEMORY"
>   QEMU_UI_OPTIONS="-show-cursor -usb -usbdevice wacom-tablet"
>
> @@ -414,7 +444,11 @@ if [ "$MACHINE" = "qemuppc" ]; then
>       MACHINE_SUBTYPE=mac99
>       CPU_SUBTYPE=G4
>       QEMU_UI_OPTIONS="$QEMU_UI_OPTIONS"
> -    QEMU_NETWORK_CMD="-net nic,model=pcnet $QEMU_TAP_CMD"
> +    if [ "$SLIRP_ENABLED" = "yes" ]; then
> +        QEMU_NETWORK_CMD=""
> +    else
> +        QEMU_NETWORK_CMD="-net nic,model=pcnet $QEMU_TAP_CMD"
> +    fi
>       if [ "$FSTYPE" = "ext3" -o "$FSTYPE" = "btrfs" ]; then
>           KERNCMDLINE="root=/dev/hda rw console=ttyS0 console=tty $KERNEL_NETWORK_CMD mem=$QEMU_MEMORY"
>           QEMUOPTIONS="$QEMU_NETWORK_CMD -cpu $CPU_SUBTYPE -M $MACHINE_SUBTYPE -hda $ROOTFS -no-reboot $QEMU_UI_OPTIONS"
>