xref: /openbmc/qemu/include/io/channel-util.h (revision 34cc54fb)
1 /*
2  * QEMU I/O channels utility APIs
3  *
4  * Copyright (c) 2016 Red Hat, Inc.
5  *
6  * This library is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * This library is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
18  *
19  */
20 
21 #ifndef QIO_CHANNEL_UTIL_H
22 #define QIO_CHANNEL_UTIL_H
23 
24 #include "io/channel.h"
25 
26 /*
27  * This module provides helper functions that are useful when dealing
28  * with QIOChannel objects
29  */
30 
31 
32 /**
33  * qio_channel_new_fd:
34  * @fd: the file descriptor
35  * @errp: pointer to a NULL-initialized error object
36  *
37  * Create a channel for performing I/O on the file
38  * descriptor @fd. The particular subclass of QIOChannel
39  * that is returned will depend on what underlying object
40  * the file descriptor is associated with. It may be either
41  * a QIOChannelSocket or a QIOChannelFile instance. Upon
42  * success, the returned QIOChannel instance will own
43  * the @fd file descriptor, and take responsibility for
44  * closing it when no longer required. On failure, the
45  * caller is responsible for closing @fd.
46  *
47  * Returns: the channel object, or NULL on error
48  */
49 QIOChannel *qio_channel_new_fd(int fd,
50                                Error **errp);
51 
52 /**
53  * qio_channel_util_set_aio_fd_handler:
54  * @read_fd: the file descriptor for the read handler
55  * @read_ctx: the AioContext for the read handler
56  * @io_read: the read handler
57  * @write_fd: the file descriptor for the write handler
58  * @write_ctx: the AioContext for the write handler
59  * @io_write: the write handler
60  * @opaque: the opaque argument to the read and write handler
61  *
62  * Set the read and write handlers when @read_ctx and @write_ctx are non-NULL,
63  * respectively. To leave a handler in its current state, pass a NULL
64  * AioContext. To clear a handler, pass a non-NULL AioContext and a NULL
65  * handler.
66  */
67 void qio_channel_util_set_aio_fd_handler(int read_fd,
68                                          AioContext *read_ctx,
69                                          IOHandler *io_read,
70                                          int write_fd,
71                                          AioContext *write_ctx,
72                                          IOHandler *io_write,
73                                          void *opaque);
74 
75 #endif /* QIO_CHANNEL_UTIL_H */
76