[Qemu-devel] [PATCH for-2.7] char: fix waiting for TLS and telnet connection

[Qemu-devel] [PATCH for-2.7] char: fix waiting for TLS and telnet connection

[Marc-André Lureau]

Since commit d7a04fd7d5008, tcp_chr_wait_connected() was introduced,
so vhost-user could wait until a backend started successfully. In
vhost-user case, the chr socket must be plain unix, and the chr+vhost
setup happens synchronously during qemu startup.

However, with TLS and telnet socket, initial socket setup happens
asynchronously, and s->connected is not set after the socket is
accepted. In order for tcp_chr_wait_connected() to not keep accepting
new connections and proceed with the last accepted socket, it can
check for s->ioc instead.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 qemu-char.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/qemu-char.c b/qemu-char.c
index 8a0ab05..5f82ebb 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -3176,7 +3176,9 @@ static int tcp_chr_wait_connected(CharDriverState *chr, Error **errp)
     TCPCharDriver *s = chr->opaque;
     QIOChannelSocket *sioc;
 
-    while (!s->connected) {
+    /* It can't wait on s->connected, since it is set asynchronously
+     * in TLS and telnet cases, only wait for an accepted socket */
+    while (!s->ioc) {
         if (s->is_listen) {
             fprintf(stderr, "QEMU waiting for connection on: %s\n",
                     chr->filename);
-- 
2.9.0

Re: [Qemu-devel] [PATCH for-2.7] char: fix waiting for TLS and telnet connection

[Dennis Luehring]

you should push that change - can't find it on http://git.qemu.org/qemu.git

Am 16.08.2016 um 10:33 schrieb Marc-André Lureau:
> Since commit d7a04fd7d5008, tcp_chr_wait_connected() was introduced,
> so vhost-user could wait until a backend started successfully. In
> vhost-user case, the chr socket must be plain unix, and the chr+vhost
> setup happens synchronously during qemu startup.
>
> However, with TLS and telnet socket, initial socket setup happens
> asynchronously, and s->connected is not set after the socket is
> accepted. In order for tcp_chr_wait_connected() to not keep accepting
> new connections and proceed with the last accepted socket, it can
> check for s->ioc instead.
>
> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> ---
>   qemu-char.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/qemu-char.c b/qemu-char.c
> index 8a0ab05..5f82ebb 100644
> --- a/qemu-char.c
> +++ b/qemu-char.c
> @@ -3176,7 +3176,9 @@ static int tcp_chr_wait_connected(CharDriverState *chr, Error **errp)
>       TCPCharDriver *s = chr->opaque;
>       QIOChannelSocket *sioc;
>   
> -    while (!s->connected) {
> +    /* It can't wait on s->connected, since it is set asynchronously
> +     * in TLS and telnet cases, only wait for an accepted socket */
> +    while (!s->ioc) {
>           if (s->is_listen) {
>               fprintf(stderr, "QEMU waiting for connection on: %s\n",
>                       chr->filename);

Re: [Qemu-devel] [PATCH for-2.7] char: fix waiting for TLS and telnet connection

[Daniel P. Berrange]

On Tue, Aug 16, 2016 at 12:33:32PM +0400, Marc-André Lureau wrote:
> Since commit d7a04fd7d5008, tcp_chr_wait_connected() was introduced,
> so vhost-user could wait until a backend started successfully. In
> vhost-user case, the chr socket must be plain unix, and the chr+vhost
> setup happens synchronously during qemu startup.
> 
> However, with TLS and telnet socket, initial socket setup happens
> asynchronously, and s->connected is not set after the socket is
> accepted. In order for tcp_chr_wait_connected() to not keep accepting
> new connections and proceed with the last accepted socket, it can
> check for s->ioc instead.
> 
> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> ---
>  qemu-char.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/qemu-char.c b/qemu-char.c
> index 8a0ab05..5f82ebb 100644
> --- a/qemu-char.c
> +++ b/qemu-char.c
> @@ -3176,7 +3176,9 @@ static int tcp_chr_wait_connected(CharDriverState *chr, Error **errp)
>      TCPCharDriver *s = chr->opaque;
>      QIOChannelSocket *sioc;
>  
> -    while (!s->connected) {
> +    /* It can't wait on s->connected, since it is set asynchronously
> +     * in TLS and telnet cases, only wait for an accepted socket */
> +    while (!s->ioc) {
>          if (s->is_listen) {
>              fprintf(stderr, "QEMU waiting for connection on: %s\n",
>                      chr->filename);

Reviewed-by: Daniel P. Berrange <berrange@redhat.com>

This is a definite must fix for 2.7.0.

Also shows we really badly need unit tests for the chardev stuff :-)

Regards,
Daniel
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Re: [Qemu-devel] [PATCH for-2.7] char: fix waiting for TLS and telnet connection

[Marc-André Lureau]

Hi

----- Original Message -----
> On Tue, Aug 16, 2016 at 12:33:32PM +0400, Marc-André Lureau wrote:
> > Since commit d7a04fd7d5008, tcp_chr_wait_connected() was introduced,
> > so vhost-user could wait until a backend started successfully. In
> > vhost-user case, the chr socket must be plain unix, and the chr+vhost
> > setup happens synchronously during qemu startup.
> > 
> > However, with TLS and telnet socket, initial socket setup happens
> > asynchronously, and s->connected is not set after the socket is
> > accepted. In order for tcp_chr_wait_connected() to not keep accepting
> > new connections and proceed with the last accepted socket, it can
> > check for s->ioc instead.
> > 
> > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> > ---
> >  qemu-char.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/qemu-char.c b/qemu-char.c
> > index 8a0ab05..5f82ebb 100644
> > --- a/qemu-char.c
> > +++ b/qemu-char.c
> > @@ -3176,7 +3176,9 @@ static int tcp_chr_wait_connected(CharDriverState
> > *chr, Error **errp)
> >      TCPCharDriver *s = chr->opaque;
> >      QIOChannelSocket *sioc;
> >  
> > -    while (!s->connected) {
> > +    /* It can't wait on s->connected, since it is set asynchronously
> > +     * in TLS and telnet cases, only wait for an accepted socket */
> > +    while (!s->ioc) {
> >          if (s->is_listen) {
> >              fprintf(stderr, "QEMU waiting for connection on: %s\n",
> >                      chr->filename);
> 
> Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
> 
> This is a definite must fix for 2.7.0.
> 
> Also shows we really badly need unit tests for the chardev stuff :-)

That was my thought too :)

Re: [Qemu-devel] [PATCH for-2.7] char: fix waiting for TLS and telnet connection

[Peter Maydell]

On 16 August 2016 at 10:31, Daniel P. Berrange <berrange@redhat.com> wrote:
> On Tue, Aug 16, 2016 at 12:33:32PM +0400, Marc-André Lureau wrote:
>> Since commit d7a04fd7d5008, tcp_chr_wait_connected() was introduced,
>> so vhost-user could wait until a backend started successfully. In
>> vhost-user case, the chr socket must be plain unix, and the chr+vhost
>> setup happens synchronously during qemu startup.
>>
>> However, with TLS and telnet socket, initial socket setup happens
>> asynchronously, and s->connected is not set after the socket is
>> accepted. In order for tcp_chr_wait_connected() to not keep accepting
>> new connections and proceed with the last accepted socket, it can
>> check for s->ioc instead.
>>
>> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
>> ---
>>  qemu-char.c | 4 +++-
>>  1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/qemu-char.c b/qemu-char.c
>> index 8a0ab05..5f82ebb 100644
>> --- a/qemu-char.c
>> +++ b/qemu-char.c
>> @@ -3176,7 +3176,9 @@ static int tcp_chr_wait_connected(CharDriverState *chr, Error **errp)
>>      TCPCharDriver *s = chr->opaque;
>>      QIOChannelSocket *sioc;
>>
>> -    while (!s->connected) {
>> +    /* It can't wait on s->connected, since it is set asynchronously
>> +     * in TLS and telnet cases, only wait for an accepted socket */
>> +    while (!s->ioc) {
>>          if (s->is_listen) {
>>              fprintf(stderr, "QEMU waiting for connection on: %s\n",
>>                      chr->filename);
>
> Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
>
> This is a definite must fix for 2.7.0.
>
> Also shows we really badly need unit tests for the chardev stuff :-)

Applied, thanks.

-- PMM