io/channel-socket: rework qio_channel_socket_copy_fds()

We want to switch from qemu_socket_set_block() to newer
qemu_set_blocking(), which provides return status of operation,
to handle errors.

Still, we want to keep qio_channel_socket_readv() interface clean,
as currently it allocate @fds only on success.

So, in case of error, we should close all incoming fds and keep
user's @fds untouched or zero.

Let's make separate functions qio_channel_handle_fds() and
qio_channel_cleanup_fds(), to achieve what we want.

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

1 files changed, 4 insertions, 4 deletions

diff --git a/include/io/channel.h b/include/io/channel.h
index 999a8f5f23..0f25ae0069 100644
--- a/include/io/channel.h
+++ b/include/io/channel.h
@@ -124,8 +124,8 @@ struct QIOChannelClass {
      * incoming fds are set BLOCKING (unless
      * QIO_CHANNEL_READ_FLAG_FD_PRESERVE_BLOCKING flag is set) and
      * CLOEXEC (if available).
-     * @fds and @nfds are set only on success path, and untouched
-     * in case of errors.
+     * @fds and @nfds are set only on success path. Still, setting
+     * @fds and @nfds to zero is acceptable on failure path.
      */
     ssize_t (*io_readv)(QIOChannel *ioc,
                         const struct iovec *iov,
@@ -246,8 +246,8 @@ void qio_channel_set_name(QIOChannel *ioc,
  * to call close() on each file descriptor and to
  * call g_free() on the array pointer in @fds.
  * @fds allocated and set (and @nfds is set too)
- * _only_ on success path. These parameters are
- * untouched in case of errors.
+ * _only_ on success path. Still, @fds and @nfds
+ * may be set to zero on failure path.
  * qio_channel_readv_full() guarantees that all
  * incoming fds are set BLOCKING (unless
  * QIO_CHANNEL_READ_FLAG_FD_PRESERVE_BLOCKING flag