[Qemu-devel] [PATCH] migration: Fix seg with missing port

[Qemu-devel] [PATCH] migration: Fix seg with missing port

[Dr. David Alan Gilbert (git)]

From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>

The command :
   migrate tcp:localhost:

   currently segs; fix it so it now says:

   error parsing address 'localhost:'

and the same for -incoming.

(We know that errp is non-null; callers use a local_err).

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
 migration/socket.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/migration/socket.c b/migration/socket.c
index 00de1fe..6e82924 100644
--- a/migration/socket.c
+++ b/migration/socket.c
@@ -113,7 +113,9 @@ void tcp_start_outgoing_migration(MigrationState *s,
                                   Error **errp)
 {
     SocketAddress *saddr = tcp_build_address(host_port, errp);
-    socket_start_outgoing_migration(s, saddr, errp);
+    if (!*errp) {
+        socket_start_outgoing_migration(s, saddr, errp);
+    }
 }
 
 void unix_start_outgoing_migration(MigrationState *s,
@@ -175,7 +177,9 @@ static void socket_start_incoming_migration(SocketAddress *saddr,
 void tcp_start_incoming_migration(const char *host_port, Error **errp)
 {
     SocketAddress *saddr = tcp_build_address(host_port, errp);
-    socket_start_incoming_migration(saddr, errp);
+    if (!*errp) {
+        socket_start_incoming_migration(saddr, errp);
+    }
 }
 
 void unix_start_incoming_migration(const char *path, Error **errp)
-- 
2.7.4

Re: [Qemu-devel] [PATCH] migration: Fix seg with missing port

[Daniel P. Berrange]

On Mon, Sep 12, 2016 at 08:03:54PM +0100, Dr. David Alan Gilbert (git) wrote:
> From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
> 
> The command :
>    migrate tcp:localhost:
> 
>    currently segs; fix it so it now says:
> 
>    error parsing address 'localhost:'
> 
> and the same for -incoming.
> 
> (We know that errp is non-null; callers use a local_err).

I'd still be more comfortable with us using a local Error
object here, as it illustrates best practice and protects
against future accidents.

> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> ---
>  migration/socket.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/migration/socket.c b/migration/socket.c
> index 00de1fe..6e82924 100644
> --- a/migration/socket.c
> +++ b/migration/socket.c
> @@ -113,7 +113,9 @@ void tcp_start_outgoing_migration(MigrationState *s,
>                                    Error **errp)
>  {
>      SocketAddress *saddr = tcp_build_address(host_port, errp);
> -    socket_start_outgoing_migration(s, saddr, errp);
> +    if (!*errp) {
> +        socket_start_outgoing_migration(s, saddr, errp);
> +    }
>  }
>  
>  void unix_start_outgoing_migration(MigrationState *s,
> @@ -175,7 +177,9 @@ static void socket_start_incoming_migration(SocketAddress *saddr,
>  void tcp_start_incoming_migration(const char *host_port, Error **errp)
>  {
>      SocketAddress *saddr = tcp_build_address(host_port, errp);
> -    socket_start_incoming_migration(saddr, errp);
> +    if (!*errp) {
> +        socket_start_incoming_migration(saddr, errp);
> +    }
>  }

Yep, makes sense


Regards,
Daniel
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Re: [Qemu-devel] [PATCH] migration: Fix seg with missing port

[Eric Blake]

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On 09/12/2016 02:11 PM, Daniel P. Berrange wrote:
> On Mon, Sep 12, 2016 at 08:03:54PM +0100, Dr. David Alan Gilbert (git) wrote:
>> From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
>>
>> The command :
>>    migrate tcp:localhost:
>>
>>    currently segs; fix it so it now says:
>>
>>    error parsing address 'localhost:'
>>
>> and the same for -incoming.
>>
>> (We know that errp is non-null; callers use a local_err).
> 
> I'd still be more comfortable with us using a local Error
> object here, as it illustrates best practice and protects
> against future accidents.

Concur. Having an example contrary to best practice makes it far too
easy for that example to be copied somewhere where it will later break.

>> +++ b/migration/socket.c
>> @@ -113,7 +113,9 @@ void tcp_start_outgoing_migration(MigrationState *s,
>>                                    Error **errp)
>>  {
>>      SocketAddress *saddr = tcp_build_address(host_port, errp);
>> -    socket_start_outgoing_migration(s, saddr, errp);
>> +    if (!*errp) {
>> +        socket_start_outgoing_migration(s, saddr, errp);
>> +    }

Since we make a decision about code flow based on whether an earlier
error occurred, this SHOULD be:

{
    Error *err = NULL;
    SocketAddress *saddr = tcp_build_address(host_port, &err);

    if (!err) {
        socket_start_outgoing_migration(s, saddr, &err);
    }
    error_propagate(errp, err);
}

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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Re: [Qemu-devel] [PATCH] migration: Fix seg with missing port

[Paolo Bonzini]

On 12/09/2016 21:03, Dr. David Alan Gilbert (git) wrote:
>      SocketAddress *saddr = tcp_build_address(host_port, errp);
> -    socket_start_outgoing_migration(s, saddr, errp);
> +    if (!*errp) {
> +        socket_start_outgoing_migration(s, saddr, errp);
> +    }
>  }
>  
>  void unix_start_outgoing_migration(MigrationState *s,
> @@ -175,7 +177,9 @@ static void socket_start_incoming_migration(SocketAddress *saddr,
>  void tcp_start_incoming_migration(const char *host_port, Error **errp)
>  {
>      SocketAddress *saddr = tcp_build_address(host_port, errp);
> -    socket_start_incoming_migration(saddr, errp);
> +    if (!*errp) {
> +        socket_start_incoming_migration(saddr, errp);
> +    }

FWIW, this less-boilerplate version was almost fine, just replace
"!*errp" with "saddr".

Paolo