Re: [Qemu-devel] [PATCH 11/18] nbd: ask and print error information from qemu-sockets

[Paolo Bonzini <pbonzini@redhat.com>]

Il 04/10/2012 22:08, Luiz Capitulino ha scritto:
> On Wed,  3 Oct 2012 16:36:58 +0200
> Paolo Bonzini <pbonzini@redhat.com> wrote:
> 
>> Before:
>>
>>     $ qemu-system-x86_64 nbd:localhost:12345
>>     inet_connect_opts: connect(ipv4,yakj.usersys.redhat.com,127.0.0.1,12345): Connection refused
>>     qemu-system-x86_64: could not open disk image nbd:localhost:12345: Connection refused
>>
>> After:
>>
>>     $ x86_64-softmmu/qemu-system-x86_64 nbd:localhost:12345
>>     qemu-system-x86_64: Failed to connect to socket: Connection refused
>>     qemu-system-x86_64: could not open disk image nbd:localhost:12345: Connection refused
>>
>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>> ---
>>  nbd.c | 39 +++++++++++++++++++++++++++++++--------
>>  1 file modificato, 31 inserzioni(+), 8 rimozioni(-)
>>
>> diff --git a/nbd.c b/nbd.c
>> index f61a288..cec5a94 100644
>> --- a/nbd.c
>> +++ b/nbd.c
>> @@ -208,7 +208,14 @@ int tcp_socket_outgoing(const char *address, uint16_t port)
>>  
>>  int tcp_socket_outgoing_spec(const char *address_and_port)
>>  {
>> -    return inet_connect(address_and_port, NULL);
>> +    Error *local_err = NULL;
>> +    int fd = inet_connect(address_and_port, &local_err);
>> +
>> +    if (local_err != NULL) {
>> +        qerror_report_err(local_err);
>> +        error_free(local_err);
> 
> Can't you propagate errp instead of using qerror_report_err()? This function
> should only be used when the caller expects QError semantics.

No, I cannot.  These functions are used only for a) qemu-nbd, for which
qerror_report_err() is ok; b) the NBD driver's bdrv_open, which is not
able to propagate errors yet.

When error propagation is added to bdrv_open they can just disappear,
replaced by direct calls to functions in qemu-sockets.c.

Paolo

>> +    }
>> +    return fd;
>>  }
>>  
>>  int tcp_socket_incoming(const char *address, uint16_t port)
>> @@ -220,22 +227,38 @@ int tcp_socket_incoming(const char *address, uint16_t port)
>>  
>>  int tcp_socket_incoming_spec(const char *address_and_port)
>>  {
>> -    char *ostr  = NULL;
>> -    int olen = 0;
>> -    return inet_listen(address_and_port, ostr, olen, SOCK_STREAM, 0, NULL);
>> +    Error *local_err = NULL;
>> +    int fd = inet_listen(address_and_port, NULL, 0, SOCK_STREAM, 0, &local_err);
>> +
>> +    if (local_err != NULL) {
>> +        qerror_report_err(local_err);
>> +        error_free(local_err);
>> +    }
>> +    return fd;
>>  }
>>  
>>  int unix_socket_incoming(const char *path)
>>  {
>> -    char *ostr = NULL;
>> -    int olen = 0;
>> +    Error *local_err = NULL;
>> +    int fd = unix_listen(path, NULL, 0, &local_err);
>>  
>> -    return unix_listen(path, ostr, olen, NULL);
>> +    if (local_err != NULL) {
>> +        qerror_report_err(local_err);
>> +        error_free(local_err);
>> +    }
>> +    return fd;
>>  }
>>  
>>  int unix_socket_outgoing(const char *path)
>>  {
>> -    return unix_connect(path, NULL);
>> +    Error *local_err = NULL;
>> +    int fd = unix_connect(path, &local_err);
>> +
>> +    if (local_err != NULL) {
>> +        qerror_report_err(local_err);
>> +        error_free(local_err);
>> +    }
>> +    return fd;
>>  }
>>  
>>  /* Basic flow for negotiation
> 
> 
>