xref: /openbmc/qemu/chardev/char-io.c (revision d2dfe0b5) 
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 "chardev/char-io.h"
26 
27 typedef struct IOWatchPoll {
28     GSource parent;
29 
30     QIOChannel *ioc;
31     GSource *src;
32 
33     IOCanReadHandler *fd_can_read;
34     GSourceFunc fd_read;
35     void *opaque;
36 } IOWatchPoll;
37 
38 static IOWatchPoll *io_watch_poll_from_source(GSource *source)
39 {
40     return container_of(source, IOWatchPoll, parent);
41 }
42 
43 static gboolean io_watch_poll_prepare(GSource *source,
44                                       gint *timeout)
45 {
46     IOWatchPoll *iwp = io_watch_poll_from_source(source);
47     bool now_active = iwp->fd_can_read(iwp->opaque) > 0;
48     bool was_active = iwp->src != NULL;
49     if (was_active == now_active) {
50         return FALSE;
51     }
52 
53     if (now_active) {
54         iwp->src = qio_channel_create_watch(
55             iwp->ioc, G_IO_IN | G_IO_ERR | G_IO_HUP | G_IO_NVAL);
56         g_source_set_callback(iwp->src, iwp->fd_read, iwp->opaque, NULL);
57         g_source_add_child_source(source, iwp->src);
58         g_source_unref(iwp->src);
59     } else {
60         g_source_remove_child_source(source, iwp->src);
61         iwp->src = NULL;
62     }
63     return FALSE;
64 }
65 
66 static gboolean io_watch_poll_dispatch(GSource *source, GSourceFunc callback,
67                                        gpointer user_data)
68 {
69     return G_SOURCE_CONTINUE;
70 }
71 
72 static GSourceFuncs io_watch_poll_funcs = {
73     .prepare = io_watch_poll_prepare,
74     .dispatch = io_watch_poll_dispatch,
75 };
76 
77 GSource *io_add_watch_poll(Chardev *chr,
78                         QIOChannel *ioc,
79                         IOCanReadHandler *fd_can_read,
80                         QIOChannelFunc fd_read,
81                         gpointer user_data,
82                         GMainContext *context)
83 {
84     IOWatchPoll *iwp;
85     char *name;
86 
87     iwp = (IOWatchPoll *) g_source_new(&io_watch_poll_funcs,
88                                        sizeof(IOWatchPoll));
89     iwp->fd_can_read = fd_can_read;
90     iwp->opaque = user_data;
91     iwp->ioc = ioc;
92     iwp->fd_read = (GSourceFunc) fd_read;
93     iwp->src = NULL;
94 
95     name = g_strdup_printf("chardev-iowatch-%s", chr->label);
96     g_source_set_name((GSource *)iwp, name);
97     g_free(name);
98 
99     g_source_attach(&iwp->parent, context);
100     g_source_unref(&iwp->parent);
101     return (GSource *)iwp;
102 }
103 
104 void remove_fd_in_watch(Chardev *chr)
105 {
106     if (chr->gsource) {
107         g_source_destroy(chr->gsource);
108         chr->gsource = NULL;
109     }
110 }
111 
112 int io_channel_send_full(QIOChannel *ioc,
113                          const void *buf, size_t len,
114                          int *fds, size_t nfds)
115 {
116     size_t offset = 0;
117 
118     while (offset < len) {
119         ssize_t ret = 0;
120         struct iovec iov = { .iov_base = (char *)buf + offset,
121                              .iov_len = len - offset };
122 
123         ret = qio_channel_writev_full(
124             ioc, &iov, 1,
125             fds, nfds, 0, NULL);
126         if (ret == QIO_CHANNEL_ERR_BLOCK) {
127             if (offset) {
128                 return offset;
129             }
130 
131             errno = EAGAIN;
132             return -1;
133         } else if (ret < 0) {
134             errno = EINVAL;
135             return -1;
136         }
137 
138         offset += ret;
139     }
140 
141     return offset;
142 }
143 
144 int io_channel_send(QIOChannel *ioc, const void *buf, size_t len)
145 {
146     return io_channel_send_full(ioc, buf, len, NULL, 0);
147 }
148