linux-user: Add support for a group of btrfs ioctls used for snapshots
[qemu.git] / chardev / char-fd.c
1 /*
2 * QEMU System Emulator
3 *
4 * Copyright (c) 2003-2008 Fabrice Bellard
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22 * THE SOFTWARE.
23 */
24
25 #include "qemu/osdep.h"
26 #include "qemu-common.h"
27 #include "qemu/module.h"
28 #include "qemu/sockets.h"
29 #include "qapi/error.h"
30 #include "chardev/char.h"
31 #include "io/channel-file.h"
32
33 #include "chardev/char-fd.h"
34 #include "chardev/char-io.h"
35
36 /* Called with chr_write_lock held. */
37 static int fd_chr_write(Chardev *chr, const uint8_t *buf, int len)
38 {
39 FDChardev *s = FD_CHARDEV(chr);
40
41 return io_channel_send(s->ioc_out, buf, len);
42 }
43
44 static gboolean fd_chr_read(QIOChannel *chan, GIOCondition cond, void *opaque)
45 {
46 Chardev *chr = CHARDEV(opaque);
47 FDChardev *s = FD_CHARDEV(opaque);
48 int len;
49 uint8_t buf[CHR_READ_BUF_LEN];
50 ssize_t ret;
51
52 len = sizeof(buf);
53 if (len > s->max_size) {
54 len = s->max_size;
55 }
56 if (len == 0) {
57 return TRUE;
58 }
59
60 ret = qio_channel_read(
61 chan, (gchar *)buf, len, NULL);
62 if (ret == 0) {
63 remove_fd_in_watch(chr);
64 qemu_chr_be_event(chr, CHR_EVENT_CLOSED);
65 return FALSE;
66 }
67 if (ret > 0) {
68 qemu_chr_be_write(chr, buf, ret);
69 }
70
71 return TRUE;
72 }
73
74 static int fd_chr_read_poll(void *opaque)
75 {
76 Chardev *chr = CHARDEV(opaque);
77 FDChardev *s = FD_CHARDEV(opaque);
78
79 s->max_size = qemu_chr_be_can_write(chr);
80 return s->max_size;
81 }
82
83 static GSource *fd_chr_add_watch(Chardev *chr, GIOCondition cond)
84 {
85 FDChardev *s = FD_CHARDEV(chr);
86 return qio_channel_create_watch(s->ioc_out, cond);
87 }
88
89 static void fd_chr_update_read_handler(Chardev *chr)
90 {
91 FDChardev *s = FD_CHARDEV(chr);
92
93 remove_fd_in_watch(chr);
94 if (s->ioc_in) {
95 chr->gsource = io_add_watch_poll(chr, s->ioc_in,
96 fd_chr_read_poll,
97 fd_chr_read, chr,
98 chr->gcontext);
99 }
100 }
101
102 static void char_fd_finalize(Object *obj)
103 {
104 Chardev *chr = CHARDEV(obj);
105 FDChardev *s = FD_CHARDEV(obj);
106
107 remove_fd_in_watch(chr);
108 if (s->ioc_in) {
109 object_unref(OBJECT(s->ioc_in));
110 }
111 if (s->ioc_out) {
112 object_unref(OBJECT(s->ioc_out));
113 }
114
115 qemu_chr_be_event(chr, CHR_EVENT_CLOSED);
116 }
117
118 int qmp_chardev_open_file_source(char *src, int flags, Error **errp)
119 {
120 int fd = -1;
121
122 TFR(fd = qemu_open(src, flags, 0666));
123 if (fd == -1) {
124 error_setg_file_open(errp, errno, src);
125 }
126 return fd;
127 }
128
129 /* open a character device to a unix fd */
130 void qemu_chr_open_fd(Chardev *chr,
131 int fd_in, int fd_out)
132 {
133 FDChardev *s = FD_CHARDEV(chr);
134 char *name;
135
136 s->ioc_in = QIO_CHANNEL(qio_channel_file_new_fd(fd_in));
137 name = g_strdup_printf("chardev-file-in-%s", chr->label);
138 qio_channel_set_name(QIO_CHANNEL(s->ioc_in), name);
139 g_free(name);
140 s->ioc_out = QIO_CHANNEL(qio_channel_file_new_fd(fd_out));
141 name = g_strdup_printf("chardev-file-out-%s", chr->label);
142 qio_channel_set_name(QIO_CHANNEL(s->ioc_out), name);
143 g_free(name);
144 qemu_set_nonblock(fd_out);
145 }
146
147 static void char_fd_class_init(ObjectClass *oc, void *data)
148 {
149 ChardevClass *cc = CHARDEV_CLASS(oc);
150
151 cc->chr_add_watch = fd_chr_add_watch;
152 cc->chr_write = fd_chr_write;
153 cc->chr_update_read_handler = fd_chr_update_read_handler;
154 }
155
156 static const TypeInfo char_fd_type_info = {
157 .name = TYPE_CHARDEV_FD,
158 .parent = TYPE_CHARDEV,
159 .instance_size = sizeof(FDChardev),
160 .instance_finalize = char_fd_finalize,
161 .class_init = char_fd_class_init,
162 .abstract = true,
163 };
164
165 static void register_types(void)
166 {
167 type_register_static(&char_fd_type_info);
168 }
169
170 type_init(register_types);