[PATCH 0/4] runqemu fixes about iptables rules and preconfigured tap

[PATCH 0/4] runqemu fixes about iptables rules and preconfigured tap

[Qi.Chen]

From: Chen Qi <Qi.Chen@windriver.com>

The following changes since commit 44c3f72684c5c920ce8af1da54a2268047342589:

  lib/oeqa/runtime: smart: add checks for smart output (2013-08-26 16:29:18 +0100)

are available in the git repository at:

  git://git.pokylinux.org/poky-contrib ChenQi/runqemu-fixes
  http://git.pokylinux.org/cgit.cgi/poky-contrib/log/?h=ChenQi/runqemu-fixes

Chen Qi (4):
  runqemu-ifdown: clean up the remaining iptables rules
  runqemu-internal: don't bring down preconfigured tap interface
  runqemu-internal: change the lock acquire/release logic
  runqemu-internal: provide more info if a preconfigured tap is used

 scripts/runqemu-ifdown   |   14 ++++++++++++++
 scripts/runqemu-internal |   20 ++++++++++----------
 2 files changed, 24 insertions(+), 10 deletions(-)

-- 
1.7.9.5

[PATCH 1/4] runqemu-ifdown: clean up the remaining iptables rules

[Qi.Chen]

From: Chen Qi <Qi.Chen@windriver.com>

The iptables rules for the tap interface are added by runqemu-ifup
everytime we use runqemu to start a qemu target. But it's not cleaned
up when runqemu exits.

This patch cleans up the remaining iptables rules for the tap interface
in runqemu-ifdown.

[YOCTO #5047]

Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
---
 scripts/runqemu-ifdown |   14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/scripts/runqemu-ifdown b/scripts/runqemu-ifdown
index 8b8c5a4..8f66cfa2 100755
--- a/scripts/runqemu-ifdown
+++ b/scripts/runqemu-ifdown
@@ -50,3 +50,17 @@ if [ ! -e "$TUNCTL" ]; then
 fi
 
 $TUNCTL -d $TAP
+
+# cleanup the remaining iptables rules
+IPTABLES=`which iptables 2> /dev/null`
+if [ "x$IPTABLES" = "x" ]; then
+	IPTABLES=/sbin/iptables
+fi
+if [ ! -x "$IPTABLES" ]; then
+	echo "$IPTABLES cannot be executed"
+	exit 1
+fi
+n=$[ (`echo $TAP | sed 's/tap//'` * 2) + 1 ]
+dest=$[ (`echo $TAP | sed 's/tap//'` * 2) + 2 ]
+$IPTABLES -D POSTROUTING -t nat -j MASQUERADE -s 192.168.7.$n/32
+$IPTABLES -D POSTROUTING -t nat -j MASQUERADE -s 192.168.7.$dest/32
-- 
1.7.9.5

[PATCH 2/4] runqemu-internal: don't bring down preconfigured tap interface

[Qi.Chen]

From: Chen Qi <Qi.Chen@windriver.com>

runqemu-ifup and runqemu-ifdown should be pairs. If we're using a
preconfigured tap interface, the runqemu-ifdown should not be invoked
to bring it down.

Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
---
 scripts/runqemu-internal |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/scripts/runqemu-internal b/scripts/runqemu-internal
index 8a6e551..8165e13 100755
--- a/scripts/runqemu-internal
+++ b/scripts/runqemu-internal
@@ -175,12 +175,14 @@ else
         POSSIBLE=`$IFCONFIG link | grep 'tap' | awk '{print $2}' | sed s/://`
         TAP=""
         LOCKFILE=""
+        USE_PRECONF_TAP="no"
         for tap in $POSSIBLE; do
             LOCKFILE="$LOCKDIR/$tap"
             echo "Acquiring lockfile for $tap..."
             acquire_lock $LOCKFILE
             if [ $? -eq 0 ]; then
                 TAP=$tap
+                USE_PRECONF_TAP="yes"
                 break
             fi
         done
@@ -215,7 +217,7 @@ else
         fi
 
         cleanup() {
-            if [ ! -e "$NOSUDO_FLAG" ]; then
+            if [ ! -e "$NOSUDO_FLAG" -a "$USE_PRECONF_TAP" = "no" ]; then
                 # Redirect stderr since we could see a LD_PRELOAD warning here if pseudo is loaded
                 # but inactive. This looks scary but is harmless
                 sudo $QEMUIFDOWN $TAP $OECORE_NATIVE_SYSROOT 2> /dev/null
-- 
1.7.9.5

[PATCH 3/4] runqemu-internal: change the lock acquire/release logic

[Qi.Chen]

From: Chen Qi <Qi.Chen@windriver.com>

Checking whether the lock file exists is sufficient for runqemu.
The contents of the lock file is not important.

This patch simplifies the lock acquire/release logic by removing the
flock mechanism. Also, we give more information to user indicating
why a tap interface is skipped.

As a side effect, the user now can easily create a lock file to
make runqemu skip a specific tap interface.

[YOCTO #5048]

Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
---
 scripts/runqemu-internal |   14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/scripts/runqemu-internal b/scripts/runqemu-internal
index 8165e13..3f8674c 100755
--- a/scripts/runqemu-internal
+++ b/scripts/runqemu-internal
@@ -135,15 +135,12 @@ else
                 return 1
             fi
 
-            touch $lockfile.lock
-            exec 8>$lockfile.lock
-            flock -n -x 8
-            if [ $? -ne 0 ]; then
-                exec 8>&-
+            if [ -e $lockfile.lock ]; then
                 return 1
+            else
+                touch $lockfile.lock
+                return 0
             fi
-
-            return 0
         }
 
         release_lock() {
@@ -154,7 +151,6 @@ else
             fi
 
             rm -f $lockfile.lock
-            exec  8>&-
         }
 
         LOCKDIR="/tmp/qemu-tap-locks"
@@ -184,6 +180,8 @@ else
                 TAP=$tap
                 USE_PRECONF_TAP="yes"
                 break
+            else
+                echo "Skipping $tap as it's locked by $LOCKFILE.lock"
             fi
         done
 
-- 
1.7.9.5

Re: [PATCH 3/4] runqemu-internal: change the lock acquire/release logic

[Richard Purdie]

On Tue, 2013-08-27 at 15:08 +0800, Qi.Chen@windriver.com wrote:
> From: Chen Qi <Qi.Chen@windriver.com>
> 
> Checking whether the lock file exists is sufficient for runqemu.
> The contents of the lock file is not important.

What happens if the runqemu script crashes and leaves the lockfile
around? Why are we removing perfectly functional code?

Cheers,

Richard

Re: [PATCH 3/4] runqemu-internal: change the lock acquire/release logic

[ChenQi]

On 08/27/2013 06:09 PM, Richard Purdie wrote:
> On Tue, 2013-08-27 at 15:08 +0800, Qi.Chen@windriver.com wrote:
>> From: Chen Qi <Qi.Chen@windriver.com>
>>
>> Checking whether the lock file exists is sufficient for runqemu.
>> The contents of the lock file is not important.
> What happens if the runqemu script crashes and leaves the lockfile
> around? Why are we removing perfectly functional code?
>
> Cheers,
>
> Richard
>
>
>
>

Yes. You're right.
I'll drop this patch and send out a V2.

Best Regards,
Chen Qi

Re: [PATCH 3/4] runqemu-internal: change the lock acquire/release logic

[Phil Blundell]

On Tue, 2013-08-27 at 15:08 +0800, Qi.Chen@windriver.com wrote:
> This patch simplifies the lock acquire/release logic by removing the
> flock mechanism.

I'm not sure that "simplifies" is an accurate description of the results
of removing flock.  How about "breaks"?

p.

Re: [PATCH 3/4] runqemu-internal: change the lock acquire/release logic

[ChenQi]

On 08/27/2013 06:14 PM, Phil Blundell wrote:
> On Tue, 2013-08-27 at 15:08 +0800, Qi.Chen@windriver.com wrote:
>> This patch simplifies the lock acquire/release logic by removing the
>> flock mechanism.
> I'm not sure that "simplifies" is an accurate description of the results
> of removing flock.  How about "breaks"?
>
> p.
>
>
>
>
>
That would be a better description.
I then realized I did break the logic.
I'll drop this patch and send out a v2.

Best Regards,
Chen Qi

[PATCH 4/4] runqemu-internal: provide more info if a preconfigured tap is used

[Qi.Chen]

From: Chen Qi <Qi.Chen@windriver.com>

We should provide the user more information if a preconfigured tap
is used. This is because the user might have manually set up the tap
interface to be used by other qemu binaries.

So at a minimum, we should let the user know how to make runqemu skip
that tap interface.

[YOCTO #5047]

Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
---
 scripts/runqemu-internal |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/runqemu-internal b/scripts/runqemu-internal
index 3f8674c..d6ceb28 100755
--- a/scripts/runqemu-internal
+++ b/scripts/runqemu-internal
@@ -211,7 +211,7 @@ else
                 TAP=$tap
             fi 
         else
-            echo "Using preconfigured tap device '$TAP'"
+            echo "Using preconfigured tap device '$TAP'. If this is not intended, create $LOCKFILE.lock to make runqemu skip $TAP."
         fi
 
         cleanup() {
-- 
1.7.9.5