chardev/char-pty.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 "qapi/error.h"
  28 #include "chardev/char.h"
  29 #include "io/channel-file.h"
  30 #include "qemu/sockets.h"
  31 #include "qemu/error-report.h"
  32 #include "qemu/module.h"
  33 #include "qemu/qemu-print.h"
  34
  35 #include "chardev/char-io.h"
  36 #include "qom/object.h"
  37
  38 struct PtyChardev {
  39     Chardev parent;
  40     QIOChannel *ioc;
  41     int read_bytes;
  42
  43     int connected;
  44     GSource *timer_src;
  45 };
  46 typedef struct PtyChardev PtyChardev;
  47
  48 DECLARE_INSTANCE_CHECKER(PtyChardev, PTY_CHARDEV,
  49                          TYPE_CHARDEV_PTY)
  50
  51 static void pty_chr_state(Chardev *chr, int connected);
  52
  53 static void pty_chr_timer_cancel(PtyChardev *s)
  54 {
  55     if (s->timer_src) {
  56         g_source_destroy(s->timer_src);
  57         g_source_unref(s->timer_src);
  58         s->timer_src = NULL;
  59     }
  60 }
  61
  62 static gboolean pty_chr_timer(gpointer opaque)
  63 {
  64     struct Chardev *chr = CHARDEV(opaque);
  65     PtyChardev *s = PTY_CHARDEV(opaque);
  66
  67     pty_chr_timer_cancel(s);
  68     if (!s->connected) {
  69         /* Next poll ... */
  70         qemu_chr_be_update_read_handlers(chr, chr->gcontext);
  71     }
  72     return FALSE;
  73 }
  74
  75 static void pty_chr_rearm_timer(Chardev *chr, int ms)
  76 {
  77     PtyChardev *s = PTY_CHARDEV(chr);
  78     char *name;
  79
  80     pty_chr_timer_cancel(s);
  81     name = g_strdup_printf("pty-timer-%s", chr->label);
  82     s->timer_src = qemu_chr_timeout_add_ms(chr, ms, pty_chr_timer, chr);
  83     g_source_set_name(s->timer_src, name);
  84     g_free(name);
  85 }
  86
  87 static void pty_chr_update_read_handler(Chardev *chr)
  88 {
  89     PtyChardev *s = PTY_CHARDEV(chr);
  90     GPollFD pfd;
  91     int rc;
  92     QIOChannelFile *fioc = QIO_CHANNEL_FILE(s->ioc);
  93
  94     pfd.fd = fioc->fd;
  95     pfd.events = G_IO_OUT;
  96     pfd.revents = 0;
  97     do {
  98         rc = g_poll(&pfd, 1, 0);
  99     } while (rc == -1 && errno == EINTR);
 100     assert(rc >= 0);
 101
 102     if (pfd.revents & G_IO_HUP) {
 103         pty_chr_state(chr, 0);
 104     } else {
 105         pty_chr_state(chr, 1);
 106     }
 107 }
 108
 109 static int char_pty_chr_write(Chardev *chr, const uint8_t *buf, int len)
 110 {
 111     PtyChardev *s = PTY_CHARDEV(chr);
 112
 113     if (!s->connected) {
 114         return len;
 115     }
 116     return io_channel_send(s->ioc, buf, len);
 117 }
 118
 119 static GSource *pty_chr_add_watch(Chardev *chr, GIOCondition cond)
 120 {
 121     PtyChardev *s = PTY_CHARDEV(chr);
 122     if (!s->connected) {
 123         return NULL;
 124     }
 125     return qio_channel_create_watch(s->ioc, cond);
 126 }
 127
 128 static int pty_chr_read_poll(void *opaque)
 129 {
 130     Chardev *chr = CHARDEV(opaque);
 131     PtyChardev *s = PTY_CHARDEV(opaque);
 132
 133     s->read_bytes = qemu_chr_be_can_write(chr);
 134     return s->read_bytes;
 135 }
 136
 137 static gboolean pty_chr_read(QIOChannel *chan, GIOCondition cond, void *opaque)
 138 {
 139     Chardev *chr = CHARDEV(opaque);
 140     PtyChardev *s = PTY_CHARDEV(opaque);
 141     gsize len;
 142     uint8_t buf[CHR_READ_BUF_LEN];
 143     ssize_t ret;
 144
 145     len = sizeof(buf);
 146     if (len > s->read_bytes) {
 147         len = s->read_bytes;
 148     }
 149     if (len == 0) {
 150         return TRUE;
 151     }
 152     ret = qio_channel_read(s->ioc, (char *)buf, len, NULL);
 153     if (ret <= 0) {
 154         pty_chr_state(chr, 0);
 155         return FALSE;
 156     } else {
 157         pty_chr_state(chr, 1);
 158         qemu_chr_be_write(chr, buf, ret);
 159     }
 160     return TRUE;
 161 }
 162
 163 static void pty_chr_state(Chardev *chr, int connected)
 164 {
 165     PtyChardev *s = PTY_CHARDEV(chr);
 166
 167     if (!connected) {
 168         remove_fd_in_watch(chr);
 169         s->connected = 0;
 170         /* (re-)connect poll interval for idle guests: once per second.
 171          * We check more frequently in case the guests sends data to
 172          * the virtual device linked to our pty. */
 173         pty_chr_rearm_timer(chr, 1000);
 174     } else {
 175         pty_chr_timer_cancel(s);
 176         if (!s->connected) {
 177             s->connected = 1;
 178             qemu_chr_be_event(chr, CHR_EVENT_OPENED);
 179         }
 180         if (!chr->gsource) {
 181             chr->gsource = io_add_watch_poll(chr, s->ioc,
 182                                                pty_chr_read_poll,
 183                                                pty_chr_read,
 184                                                chr, chr->gcontext);
 185         }
 186     }
 187 }
 188
 189 static void char_pty_finalize(Object *obj)
 190 {
 191     Chardev *chr = CHARDEV(obj);
 192     PtyChardev *s = PTY_CHARDEV(obj);
 193
 194     pty_chr_state(chr, 0);
 195     object_unref(OBJECT(s->ioc));
 196     pty_chr_timer_cancel(s);
 197     qemu_chr_be_event(chr, CHR_EVENT_CLOSED);
 198 }
 199
 200 static void char_pty_open(Chardev *chr,
 201                           ChardevBackend *backend,
 202                           bool *be_opened,
 203                           Error **errp)
 204 {
 205     PtyChardev *s;
 206     int master_fd, slave_fd;
 207     char pty_name[PATH_MAX];
 208     char *name;
 209
 210     master_fd = qemu_openpty_raw(&slave_fd, pty_name);
 211     if (master_fd < 0) {
 212         error_setg_errno(errp, errno, "Failed to create PTY");
 213         return;
 214     }
 215
 216     close(slave_fd);
 217     qemu_set_nonblock(master_fd);
 218
 219     chr->filename = g_strdup_printf("pty:%s", pty_name);
 220     qemu_printf("char device redirected to %s (label %s)\n",
 221                 pty_name, chr->label);
 222
 223     s = PTY_CHARDEV(chr);
 224     s->ioc = QIO_CHANNEL(qio_channel_file_new_fd(master_fd));
 225     name = g_strdup_printf("chardev-pty-%s", chr->label);
 226     qio_channel_set_name(QIO_CHANNEL(s->ioc), name);
 227     g_free(name);
 228     s->timer_src = NULL;
 229     *be_opened = false;
 230 }
 231
 232 static void char_pty_class_init(ObjectClass *oc, void *data)
 233 {
 234     ChardevClass *cc = CHARDEV_CLASS(oc);
 235
 236     cc->open = char_pty_open;
 237     cc->chr_write = char_pty_chr_write;
 238     cc->chr_update_read_handler = pty_chr_update_read_handler;
 239     cc->chr_add_watch = pty_chr_add_watch;
 240 }
 241
 242 static const TypeInfo char_pty_type_info = {
 243     .name = TYPE_CHARDEV_PTY,
 244     .parent = TYPE_CHARDEV,
 245     .instance_size = sizeof(PtyChardev),
 246     .instance_finalize = char_pty_finalize,
 247     .class_init = char_pty_class_init,
 248 };
 249
 250 static void register_types(void)
 251 {
 252     type_register_static(&char_pty_type_info);
 253 }
 254
 255 type_init(register_types);