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 #include "qemu/osdep.h"
  25 #include "qapi/error.h"
  26 #include "qemu-common.h"
  27 #include "sysemu/char.h"
  28 #include "io/channel-file.h"
  29 #include "qemu/sockets.h"
  30 #include "qemu/error-report.h"
  31
  32 #include "char-io.h"
  33
  34 #if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__)      \
  35     || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) \
  36     || defined(__GLIBC__)
  37
  38 typedef struct {
  39     Chardev parent;
  40     QIOChannel *ioc;
  41     int read_bytes;
  42
  43     /* Protected by the Chardev chr_write_lock.  */
  44     int connected;
  45     guint timer_tag;
  46     guint open_tag;
  47 } PtyChardev;
  48
  49 #define PTY_CHARDEV(obj) OBJECT_CHECK(PtyChardev, (obj), TYPE_CHARDEV_PTY)
  50
  51 static void pty_chr_update_read_handler_locked(Chardev *chr);
  52 static void pty_chr_state(Chardev *chr, int connected);
  53
  54 static gboolean pty_chr_timer(gpointer opaque)
  55 {
  56     struct Chardev *chr = CHARDEV(opaque);
  57     PtyChardev *s = PTY_CHARDEV(opaque);
  58
  59     qemu_mutex_lock(&chr->chr_write_lock);
  60     s->timer_tag = 0;
  61     s->open_tag = 0;
  62     if (!s->connected) {
  63         /* Next poll ... */
  64         pty_chr_update_read_handler_locked(chr);
  65     }
  66     qemu_mutex_unlock(&chr->chr_write_lock);
  67     return FALSE;
  68 }
  69
  70 /* Called with chr_write_lock held.  */
  71 static void pty_chr_rearm_timer(Chardev *chr, int ms)
  72 {
  73     PtyChardev *s = PTY_CHARDEV(chr);
  74     char *name;
  75
  76     if (s->timer_tag) {
  77         g_source_remove(s->timer_tag);
  78         s->timer_tag = 0;
  79     }
  80
  81     if (ms == 1000) {
  82         name = g_strdup_printf("pty-timer-secs-%s", chr->label);
  83         s->timer_tag = g_timeout_add_seconds(1, pty_chr_timer, chr);
  84     } else {
  85         name = g_strdup_printf("pty-timer-ms-%s", chr->label);
  86         s->timer_tag = g_timeout_add(ms, pty_chr_timer, chr);
  87     }
  88     g_source_set_name_by_id(s->timer_tag, name);
  89     g_free(name);
  90 }
  91
  92 /* Called with chr_write_lock held.  */
  93 static void pty_chr_update_read_handler_locked(Chardev *chr)
  94 {
  95     PtyChardev *s = PTY_CHARDEV(chr);
  96     GPollFD pfd;
  97     int rc;
  98     QIOChannelFile *fioc = QIO_CHANNEL_FILE(s->ioc);
  99
 100     pfd.fd = fioc->fd;
 101     pfd.events = G_IO_OUT;
 102     pfd.revents = 0;
 103     do {
 104         rc = g_poll(&pfd, 1, 0);
 105     } while (rc == -1 && errno == EINTR);
 106     assert(rc >= 0);
 107
 108     if (pfd.revents & G_IO_HUP) {
 109         pty_chr_state(chr, 0);
 110     } else {
 111         pty_chr_state(chr, 1);
 112     }
 113 }
 114
 115 static void pty_chr_update_read_handler(Chardev *chr,
 116                                         GMainContext *context)
 117 {
 118     qemu_mutex_lock(&chr->chr_write_lock);
 119     pty_chr_update_read_handler_locked(chr);
 120     qemu_mutex_unlock(&chr->chr_write_lock);
 121 }
 122
 123 /* Called with chr_write_lock held.  */
 124 static int char_pty_chr_write(Chardev *chr, const uint8_t *buf, int len)
 125 {
 126     PtyChardev *s = PTY_CHARDEV(chr);
 127
 128     if (!s->connected) {
 129         /* guest sends data, check for (re-)connect */
 130         pty_chr_update_read_handler_locked(chr);
 131         if (!s->connected) {
 132             return len;
 133         }
 134     }
 135     return io_channel_send(s->ioc, buf, len);
 136 }
 137
 138 static GSource *pty_chr_add_watch(Chardev *chr, GIOCondition cond)
 139 {
 140     PtyChardev *s = PTY_CHARDEV(chr);
 141     if (!s->connected) {
 142         return NULL;
 143     }
 144     return qio_channel_create_watch(s->ioc, cond);
 145 }
 146
 147 static int pty_chr_read_poll(void *opaque)
 148 {
 149     Chardev *chr = CHARDEV(opaque);
 150     PtyChardev *s = PTY_CHARDEV(opaque);
 151
 152     s->read_bytes = qemu_chr_be_can_write(chr);
 153     return s->read_bytes;
 154 }
 155
 156 static gboolean pty_chr_read(QIOChannel *chan, GIOCondition cond, void *opaque)
 157 {
 158     Chardev *chr = CHARDEV(opaque);
 159     PtyChardev *s = PTY_CHARDEV(opaque);
 160     gsize len;
 161     uint8_t buf[CHR_READ_BUF_LEN];
 162     ssize_t ret;
 163
 164     len = sizeof(buf);
 165     if (len > s->read_bytes) {
 166         len = s->read_bytes;
 167     }
 168     if (len == 0) {
 169         return TRUE;
 170     }
 171     ret = qio_channel_read(s->ioc, (char *)buf, len, NULL);
 172     if (ret <= 0) {
 173         pty_chr_state(chr, 0);
 174         return FALSE;
 175     } else {
 176         pty_chr_state(chr, 1);
 177         qemu_chr_be_write(chr, buf, ret);
 178     }
 179     return TRUE;
 180 }
 181
 182 static gboolean qemu_chr_be_generic_open_func(gpointer opaque)
 183 {
 184     Chardev *chr = CHARDEV(opaque);
 185     PtyChardev *s = PTY_CHARDEV(opaque);
 186
 187     s->open_tag = 0;
 188     qemu_chr_be_generic_open(chr);
 189     return FALSE;
 190 }
 191
 192 /* Called with chr_write_lock held.  */
 193 static void pty_chr_state(Chardev *chr, int connected)
 194 {
 195     PtyChardev *s = PTY_CHARDEV(chr);
 196
 197     if (!connected) {
 198         if (s->open_tag) {
 199             g_source_remove(s->open_tag);
 200             s->open_tag = 0;
 201         }
 202         remove_fd_in_watch(chr);
 203         s->connected = 0;
 204         /* (re-)connect poll interval for idle guests: once per second.
 205          * We check more frequently in case the guests sends data to
 206          * the virtual device linked to our pty. */
 207         pty_chr_rearm_timer(chr, 1000);
 208     } else {
 209         if (s->timer_tag) {
 210             g_source_remove(s->timer_tag);
 211             s->timer_tag = 0;
 212         }
 213         if (!s->connected) {
 214             g_assert(s->open_tag == 0);
 215             s->connected = 1;
 216             s->open_tag = g_idle_add(qemu_chr_be_generic_open_func, chr);
 217         }
 218         if (!chr->gsource) {
 219             chr->gsource = io_add_watch_poll(chr, s->ioc,
 220                                                pty_chr_read_poll,
 221                                                pty_chr_read,
 222                                                chr, NULL);
 223         }
 224     }
 225 }
 226
 227 static void char_pty_finalize(Object *obj)
 228 {
 229     Chardev *chr = CHARDEV(obj);
 230     PtyChardev *s = PTY_CHARDEV(obj);
 231
 232     qemu_mutex_lock(&chr->chr_write_lock);
 233     pty_chr_state(chr, 0);
 234     object_unref(OBJECT(s->ioc));
 235     if (s->timer_tag) {
 236         g_source_remove(s->timer_tag);
 237         s->timer_tag = 0;
 238     }
 239     qemu_mutex_unlock(&chr->chr_write_lock);
 240     qemu_chr_be_event(chr, CHR_EVENT_CLOSED);
 241 }
 242
 243 static void char_pty_open(Chardev *chr,
 244                           ChardevBackend *backend,
 245                           bool *be_opened,
 246                           Error **errp)
 247 {
 248     PtyChardev *s;
 249     int master_fd, slave_fd;
 250     char pty_name[PATH_MAX];
 251     char *name;
 252
 253     master_fd = qemu_openpty_raw(&slave_fd, pty_name);
 254     if (master_fd < 0) {
 255         error_setg_errno(errp, errno, "Failed to create PTY");
 256         return;
 257     }
 258
 259     close(slave_fd);
 260     qemu_set_nonblock(master_fd);
 261
 262     chr->filename = g_strdup_printf("pty:%s", pty_name);
 263     error_report("char device redirected to %s (label %s)",
 264                  pty_name, chr->label);
 265
 266     s = PTY_CHARDEV(chr);
 267     s->ioc = QIO_CHANNEL(qio_channel_file_new_fd(master_fd));
 268     name = g_strdup_printf("chardev-pty-%s", chr->label);
 269     qio_channel_set_name(QIO_CHANNEL(s->ioc), name);
 270     g_free(name);
 271     s->timer_tag = 0;
 272     *be_opened = false;
 273 }
 274
 275 static void char_pty_class_init(ObjectClass *oc, void *data)
 276 {
 277     ChardevClass *cc = CHARDEV_CLASS(oc);
 278
 279     cc->open = char_pty_open;
 280     cc->chr_write = char_pty_chr_write;
 281     cc->chr_update_read_handler = pty_chr_update_read_handler;
 282     cc->chr_add_watch = pty_chr_add_watch;
 283 }
 284
 285 static const TypeInfo char_pty_type_info = {
 286     .name = TYPE_CHARDEV_PTY,
 287     .parent = TYPE_CHARDEV,
 288     .instance_size = sizeof(PtyChardev),
 289     .instance_finalize = char_pty_finalize,
 290     .class_init = char_pty_class_init,
 291 };
 292
 293 static void register_types(void)
 294 {
 295     type_register_static(&char_pty_type_info);
 296 }
 297
 298 type_init(register_types);
 299
 300 #endif