xref: /openbmc/qemu/include/io/channel-file.h (revision 159fb790)
1 /*
2  * QEMU I/O channels files driver
3  *
4  * Copyright (c) 2015 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_FILE_H
22 #define QIO_CHANNEL_FILE_H
23 
24 #include "io/channel.h"
25 #include "qom/object.h"
26 
27 #define TYPE_QIO_CHANNEL_FILE "qio-channel-file"
28 OBJECT_DECLARE_SIMPLE_TYPE(QIOChannelFile, QIO_CHANNEL_FILE)
29 
30 
31 /**
32  * QIOChannelFile:
33  *
34  * The QIOChannelFile object provides a channel implementation
35  * that is able to perform I/O on block devices, character
36  * devices, FIFOs, pipes and plain files. While it is technically
37  * able to work on sockets too on the UNIX platform, this is not
38  * portable to Windows and lacks some extra sockets specific
39  * functionality. So the QIOChannelSocket object is recommended
40  * for that use case.
41  *
42  */
43 
44 struct QIOChannelFile {
45     QIOChannel parent;
46     int fd;
47 };
48 
49 
50 /**
51  * qio_channel_file_new_fd:
52  * @fd: the file descriptor
53  *
54  * Create a new IO channel object for a file represented
55  * by the @fd parameter. @fd can be associated with a
56  * block device, character device, fifo, pipe, or a
57  * regular file. For sockets, the QIOChannelSocket class
58  * should be used instead, as this provides greater
59  * functionality and cross platform portability.
60  *
61  * The channel will own the passed in file descriptor
62  * and will take responsibility for closing it, so the
63  * caller must not close it. If appropriate the caller
64  * should dup() its FD before opening the channel.
65  *
66  * Returns: the new channel object
67  */
68 QIOChannelFile *
69 qio_channel_file_new_fd(int fd);
70 
71 /**
72  * qio_channel_file_new_dupfd:
73  * @fd: the file descriptor
74  * @errp: pointer to initialized error object
75  *
76  * Create a new IO channel object for a file represented by the @fd
77  * parameter. Like qio_channel_file_new_fd(), but the @fd is first
78  * duplicated with dup().
79  *
80  * The channel will own the duplicated file descriptor and will take
81  * responsibility for closing it, the original FD is owned by the
82  * caller.
83  *
84  * Returns: the new channel object
85  */
86 QIOChannelFile *
87 qio_channel_file_new_dupfd(int fd, Error **errp);
88 
89 /**
90  * qio_channel_file_new_path:
91  * @path: the file path
92  * @flags: the open flags (O_RDONLY|O_WRONLY|O_RDWR, etc)
93  * @mode: the file creation mode if O_CREAT is set in @flags
94  * @errp: pointer to initialized error object
95  *
96  * Create a new IO channel object for a file represented
97  * by the @path parameter. @path can point to any
98  * type of file on which sequential I/O can be
99  * performed, whether it be a plain file, character
100  * device or block device.
101  *
102  * Returns: the new channel object
103  */
104 QIOChannelFile *
105 qio_channel_file_new_path(const char *path,
106                           int flags,
107                           mode_t mode,
108                           Error **errp);
109 
110 #endif /* QIO_CHANNEL_FILE_H */
111