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 "chardev/char-fe.h"
  32 #include "io/channel-file.h"
  33
  34 #include "chardev/char-fd.h"
  35 #include "chardev/char-io.h"
  36
  37 /* Called with chr_write_lock held.  */
  38 static int fd_chr_write(Chardev *chr, const uint8_t *buf, int len)
  39 {
  40     FDChardev *s = FD_CHARDEV(chr);
  41
  42     if (!s->ioc_out) {
  43         return -1;
  44     }
  45
  46     return io_channel_send(s->ioc_out, buf, len);
  47 }
  48
  49 static gboolean fd_chr_read(QIOChannel *chan, GIOCondition cond, void *opaque)
  50 {
  51     Chardev *chr = CHARDEV(opaque);
  52     FDChardev *s = FD_CHARDEV(opaque);
  53     int len;
  54     uint8_t buf[CHR_READ_BUF_LEN];
  55     ssize_t ret;
  56
  57     len = sizeof(buf);
  58     if (len > s->max_size) {
  59         len = s->max_size;
  60     }
  61     if (len == 0) {
  62         return TRUE;
  63     }
  64
  65     ret = qio_channel_read(
  66         chan, (gchar *)buf, len, NULL);
  67     if (ret == 0) {
  68         remove_fd_in_watch(chr);
  69         qemu_chr_be_event(chr, CHR_EVENT_CLOSED);
  70         return FALSE;
  71     }
  72     if (ret > 0) {
  73         qemu_chr_be_write(chr, buf, ret);
  74     }
  75
  76     return TRUE;
  77 }
  78
  79 static int fd_chr_read_poll(void *opaque)
  80 {
  81     Chardev *chr = CHARDEV(opaque);
  82     FDChardev *s = FD_CHARDEV(opaque);
  83
  84     s->max_size = qemu_chr_be_can_write(chr);
  85     return s->max_size;
  86 }
  87
  88 typedef struct FDSource {
  89     GSource parent;
  90
  91     GIOCondition cond;
  92 } FDSource;
  93
  94 static gboolean
  95 fd_source_prepare(GSource *source,
  96                   gint *timeout_)
  97 {
  98     FDSource *src = (FDSource *)source;
  99
 100     return src->cond != 0;
 101 }
 102
 103 static gboolean
 104 fd_source_check(GSource *source)
 105 {
 106     FDSource *src = (FDSource *)source;
 107
 108     return src->cond != 0;
 109 }
 110
 111 static gboolean
 112 fd_source_dispatch(GSource *source, GSourceFunc callback,
 113                    gpointer user_data)
 114 {
 115     FDSource *src = (FDSource *)source;
 116     FEWatchFunc func = (FEWatchFunc)callback;
 117     gboolean ret = G_SOURCE_CONTINUE;
 118
 119     if (src->cond) {
 120         ret = func(NULL, src->cond, user_data);
 121         src->cond = 0;
 122     }
 123
 124     return ret;
 125 }
 126
 127 static GSourceFuncs fd_source_funcs = {
 128   fd_source_prepare,
 129   fd_source_check,
 130   fd_source_dispatch,
 131   NULL, NULL, NULL
 132 };
 133
 134 static GSource *fd_source_new(FDChardev *chr)
 135 {
 136     return g_source_new(&fd_source_funcs, sizeof(FDSource));
 137 }
 138
 139 static gboolean child_func(GIOChannel *source,
 140                            GIOCondition condition,
 141                            gpointer data)
 142 {
 143     FDSource *parent = data;
 144
 145     parent->cond |= condition;
 146
 147     return G_SOURCE_CONTINUE;
 148 }
 149
 150 static GSource *fd_chr_add_watch(Chardev *chr, GIOCondition cond)
 151 {
 152     FDChardev *s = FD_CHARDEV(chr);
 153     g_autoptr(GSource) source = fd_source_new(s);
 154
 155     if (s->ioc_out) {
 156         g_autoptr(GSource) child = qio_channel_create_watch(s->ioc_out, cond & ~G_IO_IN);
 157         g_source_set_callback(child, (GSourceFunc)child_func, source, NULL);
 158         g_source_add_child_source(source, child);
 159     }
 160     if (s->ioc_in) {
 161         g_autoptr(GSource) child = qio_channel_create_watch(s->ioc_in, cond & ~G_IO_OUT);
 162         g_source_set_callback(child, (GSourceFunc)child_func, source, NULL);
 163         g_source_add_child_source(source, child);
 164     }
 165
 166     return g_steal_pointer(&source);
 167 }
 168
 169 static void fd_chr_update_read_handler(Chardev *chr)
 170 {
 171     FDChardev *s = FD_CHARDEV(chr);
 172
 173     remove_fd_in_watch(chr);
 174     if (s->ioc_in) {
 175         chr->gsource = io_add_watch_poll(chr, s->ioc_in,
 176                                            fd_chr_read_poll,
 177                                            fd_chr_read, chr,
 178                                            chr->gcontext);
 179     }
 180 }
 181
 182 static void char_fd_finalize(Object *obj)
 183 {
 184     Chardev *chr = CHARDEV(obj);
 185     FDChardev *s = FD_CHARDEV(obj);
 186
 187     remove_fd_in_watch(chr);
 188     if (s->ioc_in) {
 189         object_unref(OBJECT(s->ioc_in));
 190     }
 191     if (s->ioc_out) {
 192         object_unref(OBJECT(s->ioc_out));
 193     }
 194
 195     qemu_chr_be_event(chr, CHR_EVENT_CLOSED);
 196 }
 197
 198 int qmp_chardev_open_file_source(char *src, int flags, Error **errp)
 199 {
 200     int fd = -1;
 201
 202     TFR(fd = qemu_open_old(src, flags, 0666));
 203     if (fd == -1) {
 204         error_setg_file_open(errp, errno, src);
 205     }
 206     return fd;
 207 }
 208
 209 /* open a character device to a unix fd */
 210 void qemu_chr_open_fd(Chardev *chr,
 211                       int fd_in, int fd_out)
 212 {
 213     FDChardev *s = FD_CHARDEV(chr);
 214     g_autofree char *name = NULL;
 215
 216     if (fd_out >= 0) {
 217         qemu_set_nonblock(fd_out);
 218     }
 219
 220     if (fd_out == fd_in && fd_in >= 0) {
 221         s->ioc_in = QIO_CHANNEL(qio_channel_file_new_fd(fd_in));
 222         name = g_strdup_printf("chardev-file-%s", chr->label);
 223         qio_channel_set_name(QIO_CHANNEL(s->ioc_in), name);
 224         s->ioc_out = QIO_CHANNEL(object_ref(s->ioc_in));
 225         return;
 226     }
 227
 228     if (fd_in >= 0) {
 229         s->ioc_in = QIO_CHANNEL(qio_channel_file_new_fd(fd_in));
 230         name = g_strdup_printf("chardev-file-in-%s", chr->label);
 231         qio_channel_set_name(QIO_CHANNEL(s->ioc_in), name);
 232     }
 233
 234     if (fd_out >= 0) {
 235         s->ioc_out = QIO_CHANNEL(qio_channel_file_new_fd(fd_out));
 236         g_free(name);
 237         name = g_strdup_printf("chardev-file-out-%s", chr->label);
 238         qio_channel_set_name(QIO_CHANNEL(s->ioc_out), name);
 239     }
 240 }
 241
 242 static void char_fd_class_init(ObjectClass *oc, void *data)
 243 {
 244     ChardevClass *cc = CHARDEV_CLASS(oc);
 245
 246     cc->chr_add_watch = fd_chr_add_watch;
 247     cc->chr_write = fd_chr_write;
 248     cc->chr_update_read_handler = fd_chr_update_read_handler;
 249 }
 250
 251 static const TypeInfo char_fd_type_info = {
 252     .name = TYPE_CHARDEV_FD,
 253     .parent = TYPE_CHARDEV,
 254     .instance_size = sizeof(FDChardev),
 255     .instance_finalize = char_fd_finalize,
 256     .class_init = char_fd_class_init,
 257     .abstract = true,
 258 };
 259
 260 static void register_types(void)
 261 {
 262     type_register_static(&char_fd_type_info);
 263 }
 264
 265 type_init(register_types);