Re: [Qemu-devel] [PATCH 04/25] qemu-sockets: add nonblocking connect for Unix sockets

[Markus Armbruster]

Paolo Bonzini <address@hidden> writes:

> Signed-off-by: Paolo Bonzini <address@hidden>
> ---
>         v1->v2: fixed connect_state memory leaks
>
>  qemu-char.c    |  2 +-
>  qemu-sockets.c | 77 
> ++++++++++++++++++++++++++++++++++++++++++++++++----------
>  qemu_socket.h  |  6 ++++-
>  3 file modificati, 70 inserzioni(+), 15 rimozioni(-)
>
> diff --git a/qemu-char.c b/qemu-char.c
> index 3cc6cb5..8ebd582 100644
> --- a/qemu-char.c
> +++ b/qemu-char.c
> @@ -2450,7 +2450,7 @@ static CharDriverState *qemu_chr_open_socket(QemuOpts 
> *opts)
>          if (is_listen) {
>              fd = unix_listen_opts(opts, NULL);
>          } else {
> -            fd = unix_connect_opts(opts, NULL);
> +            fd = unix_connect_opts(opts, NULL, NULL, NULL);
>          }
>      } else {
>          if (is_listen) {
> diff --git a/qemu-sockets.c b/qemu-sockets.c
> index f7e67b6..6a49429 100644
> --- a/qemu-sockets.c
> +++ b/qemu-sockets.c
> @@ -252,16 +252,19 @@ static void wait_for_connect(void *opaque)
>      }
>  
>      /* try to connect to the next address on the list */
> -    while (s->current_addr->ai_next != NULL && s->fd < 0) {
> -        s->current_addr = s->current_addr->ai_next;
> -        s->fd = inet_connect_addr(s->current_addr, &in_progress, s);
> -        /* connect in progress */
> -        if (in_progress) {
> -            return;
> +    if (s->current_addr) {
> +        while (s->current_addr->ai_next != NULL && s->fd < 0) {
> +            s->current_addr = s->current_addr->ai_next;
> +            s->fd = inet_connect_addr(s->current_addr, &in_progress, s);
> +            /* connect in progress */
> +            if (in_progress) {
> +                return;
> +            }
>          }
> +
> +        freeaddrinfo(s->addr_list);
>      }
>  
> -    freeaddrinfo(s->addr_list);
>      if (s->callback) {
>          s->callback(s->fd, s->opaque);
>      }
> @@ -701,11 +704,13 @@ err:
>      return -1;
>  }
>  
> -int unix_connect_opts(QemuOpts *opts, Error **errp)
> +int unix_connect_opts(QemuOpts *opts, Error **errp,
> +                      NonBlockingConnectHandler *callback, void *opaque)
>  {
>      struct sockaddr_un un;
>      const char *path = qemu_opt_get(opts, "path");
> -    int sock;
> +    ConnectState *connect_state = NULL;
> +    int sock, rc;
>  
>      if (NULL == path) {
>          fprintf(stderr, "unix connect: no path specified\n");
> @@ -717,16 +722,44 @@ int unix_connect_opts(QemuOpts *opts, Error **errp)
>          perror("socket(unix)");
>          return -1;
>      }
> +    if (callback != NULL) {
> +        connect_state = g_malloc0(sizeof(*connect_state));
> +        connect_state->callback = callback;
> +        connect_state->opaque = opaque;
> +        socket_set_nonblock(sock);
> +    }
>  
>      memset(&un, 0, sizeof(un));
>      un.sun_family = AF_UNIX;
>      snprintf(un.sun_path, sizeof(un.sun_path), "%s", path);
> -    if (connect(sock, (struct sockaddr*) &un, sizeof(un)) < 0) {
> +
> +    /* connect to peer */
> +    do {
> +        rc = 0;
> +        if (connect(sock, (struct sockaddr *) &un, sizeof(un)) < 0) {
> +            rc = -socket_error();
> +        }
> +    } while (rc == -EINTR);

Isn't this a silent EINTR bug fix?

> +
> +    if (connect_state != NULL && QEMU_SOCKET_RC_INPROGRESS(rc)) {
> +        connect_state->fd = sock;
> +        qemu_set_fd_handler2(sock, NULL, NULL, wait_for_connect,
> +                             connect_state);
> +        return sock;
> +    } else {
> +        /* non blocking socket immediate success, call callback */
> +        if (callback != NULL) {
> +            callback(sock, opaque);
> +        }
> +    }
> +
> +    if (rc < 0) {
>          fprintf(stderr, "connect(unix:%s): %s\n", path, strerror(errno));
>          close(sock);
> -     return -1;
> +        sock = -1;
>      }
>  
> +    g_free(connect_state);
>      return sock;
>  }
>  

Unlike inet_connect_opts(), this one runs callback() even when connect()
fails.  Are you sure that's what you want?

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