1 files changed, 22 insertions, 3 deletions

diff --git a/include/io/channel.h b/include/io/channel.h
index 62b6571..0f25ae0 100644
--- a/include/io/channel.h
+++ b/include/io/channel.h
@@ -36,6 +36,7 @@ OBJECT_DECLARE_TYPE(QIOChannel, QIOChannelClass,
 
 #define QIO_CHANNEL_READ_FLAG_MSG_PEEK 0x1
 #define QIO_CHANNEL_READ_FLAG_RELAXED_EOF 0x2
+#define QIO_CHANNEL_READ_FLAG_FD_PRESERVE_BLOCKING 0x4
 
 typedef enum QIOChannelFeature QIOChannelFeature;
 
@@ -46,6 +47,7 @@ enum QIOChannelFeature {
     QIO_CHANNEL_FEATURE_WRITE_ZERO_COPY,
     QIO_CHANNEL_FEATURE_READ_MSG_PEEK,
     QIO_CHANNEL_FEATURE_SEEKABLE,
+    QIO_CHANNEL_FEATURE_CONCURRENT_IO,
 };
 
 
@@ -116,6 +118,15 @@ struct QIOChannelClass {
                          size_t nfds,
                          int flags,
                          Error **errp);
+
+    /*
+     * The io_readv handler must guarantee that all
+     * 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. Still, setting
+     * @fds and @nfds to zero is acceptable on failure path.
+     */
     ssize_t (*io_readv)(QIOChannel *ioc,
                         const struct iovec *iov,
                         size_t niov,
@@ -123,6 +134,7 @@ struct QIOChannelClass {
                         size_t *nfds,
                         int flags,
                         Error **errp);
+
     int (*io_close)(QIOChannel *ioc,
                     Error **errp);
     GSource * (*io_create_watch)(QIOChannel *ioc,
@@ -233,6 +245,13 @@ void qio_channel_set_name(QIOChannel *ioc,
  * was allocated. It is the callers responsibility
  * 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. 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
+ * is set) and CLOEXEC (if available).
  *
  * It is an error to pass a non-NULL @fds parameter
  * unless qio_channel_has_feature() returns a true
@@ -512,9 +531,9 @@ int coroutine_mixed_fn qio_channel_write_all(QIOChannel *ioc,
  * return QIO_CHANNEL_ERR_BLOCK if they would otherwise
  * block on I/O
  */
-int qio_channel_set_blocking(QIOChannel *ioc,
-                             bool enabled,
-                             Error **errp);
+bool qio_channel_set_blocking(QIOChannel *ioc,
+                              bool enabled,
+                              Error **errp);
 
 /**
  * qio_channel_set_follow_coroutine_ctx: