xref: /openbmc/qemu/chardev/char-fd.c (revision a27bd6c7)
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);
171