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 GMainContext *context; 37 } IOWatchPoll; 38 39 static IOWatchPoll *io_watch_poll_from_source(GSource *source) 40 { 41 return container_of(source, IOWatchPoll, parent); 42 } 43 44 static gboolean io_watch_poll_prepare(GSource *source, 45 gint *timeout) 46 { 47 IOWatchPoll *iwp = io_watch_poll_from_source(source); 48 bool now_active = iwp->fd_can_read(iwp->opaque) > 0; 49 bool was_active = iwp->src != NULL; 50 if (was_active == now_active) { 51 return FALSE; 52 } 53 54 /* 55 * We do not register the QIOChannel watch as a child GSource. 56 * The 'prepare' function on the parent GSource will be 57 * skipped if a child GSource's 'prepare' function indicates 58 * readiness. We need this prepare function be guaranteed 59 * to run on *every* iteration of the main loop, because 60 * it is critical to ensure we remove the QIOChannel watch 61 * if 'fd_can_read' indicates the frontend cannot receive 62 * more data. 63 */ 64 if (now_active) { 65 iwp->src = qio_channel_create_watch( 66 iwp->ioc, G_IO_IN | G_IO_ERR | G_IO_HUP | G_IO_NVAL); 67 g_source_set_callback(iwp->src, iwp->fd_read, iwp->opaque, NULL); 68 g_source_attach(iwp->src, iwp->context); 69 } else { 70 g_source_destroy(iwp->src); 71 g_source_unref(iwp->src); 72 iwp->src = NULL; 73 } 74 return FALSE; 75 } 76 77 static gboolean io_watch_poll_check(GSource *source) 78 { 79 return FALSE; 80 } 81 82 static gboolean io_watch_poll_dispatch(GSource *source, GSourceFunc callback, 83 gpointer user_data) 84 { 85 abort(); 86 } 87 88 static void io_watch_poll_finalize(GSource *source) 89 { 90 IOWatchPoll *iwp = io_watch_poll_from_source(source); 91 if (iwp->src) { 92 g_source_destroy(iwp->src); 93 g_source_unref(iwp->src); 94 iwp->src = NULL; 95 } 96 } 97 98 static GSourceFuncs io_watch_poll_funcs = { 99 .prepare = io_watch_poll_prepare, 100 .check = io_watch_poll_check, 101 .dispatch = io_watch_poll_dispatch, 102 .finalize = io_watch_poll_finalize, 103 }; 104 105 GSource *io_add_watch_poll(Chardev *chr, 106 QIOChannel *ioc, 107 IOCanReadHandler *fd_can_read, 108 QIOChannelFunc fd_read, 109 gpointer user_data, 110 GMainContext *context) 111 { 112 IOWatchPoll *iwp; 113 char *name; 114 115 iwp = (IOWatchPoll *) g_source_new(&io_watch_poll_funcs, 116 sizeof(IOWatchPoll)); 117 iwp->fd_can_read = fd_can_read; 118 iwp->opaque = user_data; 119 iwp->ioc = ioc; 120 iwp->fd_read = (GSourceFunc) fd_read; 121 iwp->src = NULL; 122 iwp->context = context; 123 124 name = g_strdup_printf("chardev-iowatch-%s", chr->label); 125 g_source_set_name((GSource *)iwp, name); 126 g_free(name); 127 128 g_source_attach(&iwp->parent, context); 129 g_source_unref(&iwp->parent); 130 return (GSource *)iwp; 131 } 132 133 static void io_remove_watch_poll(GSource *source) 134 { 135 IOWatchPoll *iwp; 136 137 iwp = io_watch_poll_from_source(source); 138 g_source_destroy(&iwp->parent); 139 } 140 141 void remove_fd_in_watch(Chardev *chr) 142 { 143 if (chr->gsource) { 144 io_remove_watch_poll(chr->gsource); 145 chr->gsource = NULL; 146 } 147 } 148 149 int io_channel_send_full(QIOChannel *ioc, 150 const void *buf, size_t len, 151 int *fds, size_t nfds) 152 { 153 size_t offset = 0; 154 155 while (offset < len) { 156 ssize_t ret = 0; 157 struct iovec iov = { .iov_base = (char *)buf + offset, 158 .iov_len = len - offset }; 159 160 ret = qio_channel_writev_full( 161 ioc, &iov, 1, 162 fds, nfds, 0, NULL); 163 if (ret == QIO_CHANNEL_ERR_BLOCK) { 164 if (offset) { 165 return offset; 166 } 167 168 errno = EAGAIN; 169 return -1; 170 } else if (ret < 0) { 171 errno = EINVAL; 172 return -1; 173 } 174 175 offset += ret; 176 } 177 178 return offset; 179 } 180 181 int io_channel_send(QIOChannel *ioc, const void *buf, size_t len) 182 { 183 return io_channel_send_full(ioc, buf, len, NULL, 0); 184 } 185