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