Re: [RFC PATCH v4 10/11] qemu-sockets: introduce socket_uri()

[Markus Armbruster <armbru@redhat.com>]

Laurent Vivier <lvivier@redhat.com> writes:

> On 29/06/2022 13:26, Markus Armbruster wrote:
>> Laurent Vivier <lvivier@redhat.com> writes:
>> 
>>> Format a string URI from a SocketAddress.
>>>
>>> Original code from hmp-cmds.c:SocketAddress_to_str()
>>>
>>> Replace 'tcp:' by 'inet:' (because 'inet' can be also 'udp').
>> 
>> This one's merely misleading.
>> 
>>> Replace 'tcp:' by 'vsock:' with vsock socket type.
>> 
>> This one's positively wrong: it makes a vsock address look like an inet
>> address with CID misinterpreted as host.  Goes back to commit 9aca82ba31
>> "migration: Create socket-address parameter"
>> 
>>> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
>>> ---
>>>   include/qemu/sockets.h |  2 +-
>>>   monitor/hmp-cmds.c     | 23 +----------------------
>>>   util/qemu-sockets.c    | 20 ++++++++++++++++++++
>>>   3 files changed, 22 insertions(+), 23 deletions(-)
>>>
>>> diff --git a/include/qemu/sockets.h b/include/qemu/sockets.h
>>> index 47194b9732f8..3e2ae7e21705 100644
>>> --- a/include/qemu/sockets.h
>>> +++ b/include/qemu/sockets.h
>>> @@ -41,6 +41,7 @@ int unix_listen(const char *path, Error **errp);
>>>   int unix_connect(const char *path, Error **errp);
>>>   
>>>   SocketAddress *socket_parse(const char *str, Error **errp);
>>> +char *socket_uri(SocketAddress *addr);
>>>   int socket_connect(SocketAddress *addr, Error **errp);
>>>   int socket_listen(SocketAddress *addr, int num, Error **errp);
>>>   void socket_listen_cleanup(int fd, Error **errp);
>>> @@ -123,5 +124,4 @@ SocketAddress *socket_address_flatten(SocketAddressLegacy *addr);
>>>    * Return 0 on success.
>>>    */
>>>   int socket_address_parse_named_fd(SocketAddress *addr, Error **errp);
>>> -
>>>   #endif /* QEMU_SOCKETS_H */
>>> diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c
>>> index 47a27326eef7..eb0fe0a293b8 100644
>>> --- a/monitor/hmp-cmds.c
>>> +++ b/monitor/hmp-cmds.c
>>> @@ -197,27 +197,6 @@ void hmp_info_mice(Monitor *mon, const QDict *qdict)
>>>       qapi_free_MouseInfoList(mice_list);
>>>   }
>>>   
>>> -static char *SocketAddress_to_str(SocketAddress *addr)
>>> -{
>>> -    switch (addr->type) {
>>> -    case SOCKET_ADDRESS_TYPE_INET:
>>> -        return g_strdup_printf("tcp:%s:%s",
>>> -                               addr->u.inet.host,
>>> -                               addr->u.inet.port);
>>> -    case SOCKET_ADDRESS_TYPE_UNIX:
>>> -        return g_strdup_printf("unix:%s",
>>> -                               addr->u.q_unix.path);
>>> -    case SOCKET_ADDRESS_TYPE_FD:
>>> -        return g_strdup_printf("fd:%s", addr->u.fd.str);
>>> -    case SOCKET_ADDRESS_TYPE_VSOCK:
>>> -        return g_strdup_printf("tcp:%s:%s",
>>> -                               addr->u.vsock.cid,
>>> -                               addr->u.vsock.port);
>>> -    default:
>>> -        return g_strdup("unknown address type");
>>> -    }
>>> -}
>>> -
>>>   void hmp_info_migrate(Monitor *mon, const QDict *qdict)
>>>   {
>>>       MigrationInfo *info;
>>> @@ -375,7 +354,7 @@ void hmp_info_migrate(Monitor *mon, const QDict *qdict)
>>>           monitor_printf(mon, "socket address: [\n");
>>>   
>>>           for (addr = info->socket_address; addr; addr = addr->next) {
>>> -            char *s = SocketAddress_to_str(addr->value);
>>> +            char *s = socket_uri(addr->value);
>>>               monitor_printf(mon, "\t%s\n", s);
>>>               g_free(s);
>>>           }
>>> diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c
>>> index 13b5b197f9ea..4efc2ce8b074 100644
>>> --- a/util/qemu-sockets.c
>>> +++ b/util/qemu-sockets.c
>>> @@ -1098,6 +1098,26 @@ int unix_connect(const char *path, Error **errp)
>>>       return sock;
>>>   }
>>>   
>>> +char *socket_uri(SocketAddress *addr)
>>> +{
>>> +    switch (addr->type) {
>>> +    case SOCKET_ADDRESS_TYPE_INET:
>>> +        return g_strdup_printf("inet:%s:%s",
>>> +                               addr->u.inet.host,
>>> +                               addr->u.inet.port);
>>> +    case SOCKET_ADDRESS_TYPE_UNIX:
>>> +        return g_strdup_printf("unix:%s",
>>> +                               addr->u.q_unix.path);
>>> +    case SOCKET_ADDRESS_TYPE_FD:
>>> +        return g_strdup_printf("fd:%s", addr->u.fd.str);
>>> +    case SOCKET_ADDRESS_TYPE_VSOCK:
>>> +        return g_strdup_printf("vsock:%s:%s",
>>> +                               addr->u.vsock.cid,
>>> +                               addr->u.vsock.port);
>>> +    default:
>>> +        return g_strdup("unknown address type");
>>> +    }
>>> +}
>>>   
>>>   SocketAddress *socket_parse(const char *str, Error **errp)
>>>   {
>> 
>> Why do you move and rename?  I'm not objecting, I just want to know the
>> reason :)
>
> I missed your comment before sending the v5.
>
> I move and rename because this function is the counterpart for socket_parse(), so make the 
> name similar and put the function in the same place.

Fair enough.  Recommend to work this into the commit message.  Could be
easier to write up if you make it a separate commit.

While there, you could also work in my review comments on why you're
replacing the 'tcp:' prefix.  Possible additional reason: consistency
with socket_parse().

Hmm, it's not actually consistent: socket_parse() doesn't recognize an
"inet:" prefix.  Omit it in socket_uri()?

> Perhaps it should also be improved to display all the options ("keep-alive", "mptcp", ...) 
> that socket_parse() is able to decode?

Maybe.  Requires a review of how it is used.