Re: [Qemu-devel] [PATCH v9 2/4] sockets: change inet_connect() to support nonblock socket

[Amos Kong]

On 25/04/12 13:00, Orit Wasserman wrote:
> On 04/25/2012 06:32 AM, Amos Kong wrote:
> > Add a bool argument to inet_connect() to assign if set socket
> > to block/nonblock, and delete original argument 'socktype'
> > that is unused.
> > Add a new argument to inet_connect()/inet_connect_opts(),
> > to pass back connect error by error class.
> >
> > Retry to connect when -EINTR is got. Connect's successful
> > for nonblock socket when following errors are got, user
> > should wait for connecting by select():
> >    -EINPROGRESS
> >    -EWOULDBLOCK (win32)
> >    -WSAEALREADY (win32)
> >
> > Change nbd, vnc to use new interface.
> >
> > Changes from v7:
> > - posix: let EWOULDBLOCK fall through to CONNECT_FAILED path
> > - fix typo
> >
> > Changes from v8:
> > - reuse rc variable
> > - fix a NULL pointer dereference
> >
> > Signed-off-by: Amos Kong<address@hidden>
> > ---
> >   nbd.c          |    2 +-
> >   qemu-char.c    |    2 +-
> >   qemu-sockets.c |   46 ++++++++++++++++++++++++++++++++++++++++------
> >   qemu_socket.h  |    6 ++++--
> >   ui/vnc.c       |    2 +-
> >   5 files changed, 47 insertions(+), 11 deletions(-)
> >
> > diff --git a/nbd.c b/nbd.c
> > index 406e555..bb71f00 100644
> > --- a/nbd.c
> > +++ b/nbd.c
> > @@ -146,7 +146,7 @@ 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, SOCK_STREAM);
> > +    return inet_connect(address_and_port, true, NULL);
> >   }
> >
> >   int tcp_socket_incoming(const char *address, uint16_t port)
> > diff --git a/qemu-char.c b/qemu-char.c
> > index 74c60e1..aeee2e8 100644
> > --- a/qemu-char.c
> > +++ b/qemu-char.c
> > @@ -2444,7 +2444,7 @@ static CharDriverState *qemu_chr_open_socket(QemuOpts 
> > *opts)
> >           if (is_listen) {
> >               fd = inet_listen_opts(opts, 0);
> >           } else {
> > -            fd = inet_connect_opts(opts);
> > +            fd = inet_connect_opts(opts, NULL);
> >           }
> >       }
> >       if (fd<  0) {
> > diff --git a/qemu-sockets.c b/qemu-sockets.c
> > index 6bcb8e3..243af67 100644
> > --- a/qemu-sockets.c
> > +++ b/qemu-sockets.c
> > @@ -51,6 +51,9 @@ static QemuOptsList dummy_opts = {
> >           },{
> >               .name = "ipv6",
> >               .type = QEMU_OPT_BOOL,
> > +        },{
> > +            .name = "block",
> > +            .type = QEMU_OPT_BOOL,
> >           },
> >           { /* end if list */ }
> >       },
> > @@ -194,7 +197,7 @@ listen:
> >       return slisten;
> >   }
> >
> > -int inet_connect_opts(QemuOpts *opts)
> > +int inet_connect_opts(QemuOpts *opts, Error **errp)
> >   {
> >       struct addrinfo ai,*res,*e;
> >       const char *addr;
> > @@ -202,6 +205,7 @@ int inet_connect_opts(QemuOpts *opts)
> >       char uaddr[INET6_ADDRSTRLEN+1];
> >       char uport[33];
> >       int sock,rc;
> > +    bool block;
> >
> >       memset(&ai,0, sizeof(ai));
> >       ai.ai_flags = AI_CANONNAME | AI_ADDRCONFIG;
> > @@ -210,8 +214,10 @@ int inet_connect_opts(QemuOpts *opts)
> >
> >       addr = qemu_opt_get(opts, "host");
> >       port = qemu_opt_get(opts, "port");
> > +    block = qemu_opt_get_bool(opts, "block", 0);
> >       if (addr == NULL || port == NULL) {
> >           fprintf(stderr, "inet_connect: host and/or port not specified\n");
> > +        error_set(errp, QERR_SOCKET_CREATE_FAILED);
> >           return -1;
> >       }
> >
> > @@ -224,6 +230,7 @@ int inet_connect_opts(QemuOpts *opts)
> >       if (0 != (rc = getaddrinfo(addr, port,&ai,&res))) {
> >           fprintf(stderr,"getaddrinfo(%s,%s): %s\n", addr, port,
> >                   gai_strerror(rc));
> > +        error_set(errp, QERR_SOCKET_CREATE_FAILED);
> >         return -1;
> >       }
> >
> > @@ -241,19 +248,40 @@ int inet_connect_opts(QemuOpts *opts)
> >               continue;
> >           }
> >           setsockopt(sock,SOL_SOCKET,SO_REUSEADDR,(void*)&on,sizeof(on));
> > -
> > +        if (!block) {
> > +            socket_set_nonblock(sock);
> > +        }
> >           /* connect to peer */
> > -        if (connect(sock,e->ai_addr,e->ai_addrlen)<  0) {
> > +        do {
> > +            rc = 0;
> > +            if (connect(sock, e->ai_addr, e->ai_addrlen)<  0) {
> > +                rc = -socket_error();
> > +            }
> > +        } while (rc == -EINTR);
> > +
> > +  #ifdef _WIN32
> > +        if (!block&&  (rc == -EINPROGRESS || rc == -EWOULDBLOCK
> > +                       || rc == -WSAEALREADY)) {
> > +  #else
> > +        if (!block&&  (rc == -EINPROGRESS)) {
> > +  #endif
> > +            error_set(errp, QERR_SOCKET_CONNECT_IN_PROGRESS);
> > +        }
> > +        if (rc<  0&&  (!errp || !error_is_type(*errp,
> > +            QERR_SOCKET_CONNECT_IN_PROGRESS))) {
> This is means we don't handle non-blocking correctly if errp is NULL.
> I think this can work:
> else if (rc<  0) {

yes, it works. Have sent v10.

Thanks

> Orit
> > +
> >               if (NULL == e->ai_next)
> >                   fprintf(stderr, "%s: connect(%s,%s,%s,%s): %s\n", 
> > __FUNCTION__,
> >                           inet_strfamily(e->ai_family),
> >                           e->ai_canonname, uaddr, uport, strerror(errno));
> >               closesocket(sock);
> > +            sock = -1;
> >               continue;
> >           }
> >           freeaddrinfo(res);
> >           return sock;
> >       }
> > +    error_set(errp, QERR_SOCKET_CONNECT_FAILED);
> >       freeaddrinfo(res);

...

--
                        Amos.