xref: /openbmc/qemu/chardev/char-fd.c (revision b86caf7a)
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 #include "qemu/osdep.h"
25 #include "qemu/sockets.h"
26 #include "qapi/error.h"
27 #include "qemu-common.h"
28 #include "chardev/char.h"
29 #include "io/channel-file.h"
30 
31 #include "chardev/char-fd.h"
32 #include "chardev/char-io.h"
33 
34 /* Called with chr_write_lock held.  */
35 static int fd_chr_write(Chardev *chr, const uint8_t *buf, int len)
36 {
37     FDChardev *s = FD_CHARDEV(chr);
38 
39     return io_channel_send(s->ioc_out, buf, len);
40 }
41 
42 static gboolean fd_chr_read(QIOChannel *chan, GIOCondition cond, void *opaque)
43 {
44     Chardev *chr = CHARDEV(opaque);
45     FDChardev *s = FD_CHARDEV(opaque);
46     int len;
47     uint8_t buf[CHR_READ_BUF_LEN];
48     ssize_t ret;
49 
50     len = sizeof(buf);
51     if (len > s->max_size) {
52         len = s->max_size;
53     }
54     if (len == 0) {
55         return TRUE;
56     }
57 
58     ret = qio_channel_read(
59         chan, (gchar *)buf, len, NULL);
60     if (ret == 0) {
61         remove_fd_in_watch(chr);
62         qemu_chr_be_event(chr, CHR_EVENT_CLOSED);
63         return FALSE;
64     }
65     if (ret > 0) {
66         qemu_chr_be_write(chr, buf, ret);
67     }
68 
69     return TRUE;
70 }
71 
72 static int fd_chr_read_poll(void *opaque)
73 {
74     Chardev *chr = CHARDEV(opaque);
75     FDChardev *s = FD_CHARDEV(opaque);
76 
77     s->max_size = qemu_chr_be_can_write(chr);
78     return s->max_size;
79 }
80 
81 static GSource *fd_chr_add_watch(Chardev *chr, GIOCondition cond)
82 {
83     FDChardev *s = FD_CHARDEV(chr);
84     return qio_channel_create_watch(s->ioc_out, cond);
85 }
86 
87 static void fd_chr_update_read_handler(Chardev *chr)
88 {
89     FDChardev *s = FD_CHARDEV(chr);
90 
91     remove_fd_in_watch(chr);
92     if (s->ioc_in) {
93         chr->gsource = io_add_watch_poll(chr, s->ioc_in,
94                                            fd_chr_read_poll,
95                                            fd_chr_read, chr,
96                                            chr->gcontext);
97     }
98 }
99 
100 static void char_fd_finalize(Object *obj)
101 {
102     Chardev *chr = CHARDEV(obj);
103     FDChardev *s = FD_CHARDEV(obj);
104 
105     remove_fd_in_watch(chr);
106     if (s->ioc_in) {
107         object_unref(OBJECT(s->ioc_in));
108     }
109     if (s->ioc_out) {
110         object_unref(OBJECT(s->ioc_out));
111     }
112 
113     qemu_chr_be_event(chr, CHR_EVENT_CLOSED);
114 }
115 
116 int qmp_chardev_open_file_source(char *src, int flags, Error **errp)
117 {
118     int fd = -1;
119 
120     TFR(fd = qemu_open(src, flags, 0666));
121     if (fd == -1) {
122         error_setg_file_open(errp, errno, src);
123     }
124     return fd;
125 }
126 
127 /* open a character device to a unix fd */
128 void qemu_chr_open_fd(Chardev *chr,
129                       int fd_in, int fd_out)
130 {
131     FDChardev *s = FD_CHARDEV(chr);
132     char *name;
133 
134     s->ioc_in = QIO_CHANNEL(qio_channel_file_new_fd(fd_in));
135     name = g_strdup_printf("chardev-file-in-%s", chr->label);
136     qio_channel_set_name(QIO_CHANNEL(s->ioc_in), name);
137     g_free(name);
138     s->ioc_out = QIO_CHANNEL(qio_channel_file_new_fd(fd_out));
139     name = g_strdup_printf("chardev-file-out-%s", chr->label);
140     qio_channel_set_name(QIO_CHANNEL(s->ioc_out), name);
141     g_free(name);
142     qemu_set_nonblock(fd_out);
143 }
144 
145 static void char_fd_class_init(ObjectClass *oc, void *data)
146 {
147     ChardevClass *cc = CHARDEV_CLASS(oc);
148 
149     cc->chr_add_watch = fd_chr_add_watch;
150     cc->chr_write = fd_chr_write;
151     cc->chr_update_read_handler = fd_chr_update_read_handler;
152 }
153 
154 static const TypeInfo char_fd_type_info = {
155     .name = TYPE_CHARDEV_FD,
156     .parent = TYPE_CHARDEV,
157     .instance_size = sizeof(FDChardev),
158     .instance_finalize = char_fd_finalize,
159     .class_init = char_fd_class_init,
160     .abstract = true,
161 };
162 
163 static void register_types(void)
164 {
165     type_register_static(&char_fd_type_info);
166 }
167 
168 type_init(register_types);
169