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 "chardev/char.h"
  28 #include "io/channel-file.h"
  29 #include "qemu/sockets.h"
  30 #include "qemu/error-report.h"
  31
  32 #include "chardev/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 {
 117     qemu_mutex_lock(&chr->chr_write_lock);
 118     pty_chr_update_read_handler_locked(chr);
 119     qemu_mutex_unlock(&chr->chr_write_lock);
 120 }
 121
 122 /* Called with chr_write_lock held.  */
 123 static int char_pty_chr_write(Chardev *chr, const uint8_t *buf, int len)
 124 {
 125     PtyChardev *s = PTY_CHARDEV(chr);
 126
 127     if (!s->connected) {
 128         /* guest sends data, check for (re-)connect */
 129         pty_chr_update_read_handler_locked(chr);
 130         if (!s->connected) {
 131             return len;
 132         }
 133     }
 134     return io_channel_send(s->ioc, buf, len);
 135 }
 136
 137 static GSource *pty_chr_add_watch(Chardev *chr, GIOCondition cond)
 138 {
 139     PtyChardev *s = PTY_CHARDEV(chr);
 140     if (!s->connected) {
 141         return NULL;
 142     }
 143     return qio_channel_create_watch(s->ioc, cond);
 144 }
 145
 146 static int pty_chr_read_poll(void *opaque)
 147 {
 148     Chardev *chr = CHARDEV(opaque);
 149     PtyChardev *s = PTY_CHARDEV(opaque);
 150
 151     s->read_bytes = qemu_chr_be_can_write(chr);
 152     return s->read_bytes;
 153 }
 154
 155 static gboolean pty_chr_read(QIOChannel *chan, GIOCondition cond, void *opaque)
 156 {
 157     Chardev *chr = CHARDEV(opaque);
 158     PtyChardev *s = PTY_CHARDEV(opaque);
 159     gsize len;
 160     uint8_t buf[CHR_READ_BUF_LEN];
 161     ssize_t ret;
 162
 163     len = sizeof(buf);
 164     if (len > s->read_bytes) {
 165         len = s->read_bytes;
 166     }
 167     if (len == 0) {
 168         return TRUE;
 169     }
 170     ret = qio_channel_read(s->ioc, (char *)buf, len, NULL);
 171     if (ret <= 0) {
 172         pty_chr_state(chr, 0);
 173         return FALSE;
 174     } else {
 175         pty_chr_state(chr, 1);
 176         qemu_chr_be_write(chr, buf, ret);
 177     }
 178     return TRUE;
 179 }
 180
 181 static gboolean qemu_chr_be_generic_open_func(gpointer opaque)
 182 {
 183     Chardev *chr = CHARDEV(opaque);
 184     PtyChardev *s = PTY_CHARDEV(opaque);
 185
 186     s->open_tag = 0;
 187     qemu_chr_be_event(chr, CHR_EVENT_OPENED);
 188     return FALSE;
 189 }
 190
 191 /* Called with chr_write_lock held.  */
 192 static void pty_chr_state(Chardev *chr, int connected)
 193 {
 194     PtyChardev *s = PTY_CHARDEV(chr);
 195
 196     if (!connected) {
 197         if (s->open_tag) {
 198             g_source_remove(s->open_tag);
 199             s->open_tag = 0;
 200         }
 201         remove_fd_in_watch(chr);
 202         s->connected = 0;
 203         /* (re-)connect poll interval for idle guests: once per second.
 204          * We check more frequently in case the guests sends data to
 205          * the virtual device linked to our pty. */
 206         pty_chr_rearm_timer(chr, 1000);
 207     } else {
 208         if (s->timer_tag) {
 209             g_source_remove(s->timer_tag);
 210             s->timer_tag = 0;
 211         }
 212         if (!s->connected) {
 213             g_assert(s->open_tag == 0);
 214             s->connected = 1;
 215             s->open_tag = g_idle_add(qemu_chr_be_generic_open_func, chr);
 216         }
 217         if (!chr->gsource) {
 218             chr->gsource = io_add_watch_poll(chr, s->ioc,
 219                                                pty_chr_read_poll,
 220                                                pty_chr_read,
 221                                                chr, chr->gcontext);
 222         }
 223     }
 224 }
 225
 226 static void char_pty_finalize(Object *obj)
 227 {
 228     Chardev *chr = CHARDEV(obj);
 229     PtyChardev *s = PTY_CHARDEV(obj);
 230
 231     qemu_mutex_lock(&chr->chr_write_lock);
 232     pty_chr_state(chr, 0);
 233     object_unref(OBJECT(s->ioc));
 234     if (s->timer_tag) {
 235         g_source_remove(s->timer_tag);
 236         s->timer_tag = 0;
 237     }
 238     qemu_mutex_unlock(&chr->chr_write_lock);
 239     qemu_chr_be_event(chr, CHR_EVENT_CLOSED);
 240 }
 241
 242 static void char_pty_open(Chardev *chr,
 243                           ChardevBackend *backend,
 244                           bool *be_opened,
 245                           Error **errp)
 246 {
 247     PtyChardev *s;
 248     int master_fd, slave_fd;
 249     char pty_name[PATH_MAX];
 250     char *name;
 251
 252     master_fd = qemu_openpty_raw(&slave_fd, pty_name);
 253     if (master_fd < 0) {
 254         error_setg_errno(errp, errno, "Failed to create PTY");
 255         return;
 256     }
 257
 258     close(slave_fd);
 259     qemu_set_nonblock(master_fd);
 260
 261     chr->filename = g_strdup_printf("pty:%s", pty_name);
 262     error_report("char device redirected to %s (label %s)",
 263                  pty_name, chr->label);
 264
 265     s = PTY_CHARDEV(chr);
 266     s->ioc = QIO_CHANNEL(qio_channel_file_new_fd(master_fd));
 267     name = g_strdup_printf("chardev-pty-%s", chr->label);
 268     qio_channel_set_name(QIO_CHANNEL(s->ioc), name);
 269     g_free(name);
 270     s->timer_tag = 0;
 271     *be_opened = false;
 272 }
 273
 274 static void char_pty_class_init(ObjectClass *oc, void *data)
 275 {
 276     ChardevClass *cc = CHARDEV_CLASS(oc);
 277
 278     cc->open = char_pty_open;
 279     cc->chr_write = char_pty_chr_write;
 280     cc->chr_update_read_handler = pty_chr_update_read_handler;
 281     cc->chr_add_watch = pty_chr_add_watch;
 282 }
 283
 284 static const TypeInfo char_pty_type_info = {
 285     .name = TYPE_CHARDEV_PTY,
 286     .parent = TYPE_CHARDEV,
 287     .instance_size = sizeof(PtyChardev),
 288     .instance_finalize = char_pty_finalize,
 289     .class_init = char_pty_class_init,
 290 };
 291
 292 static void register_types(void)
 293 {
 294     type_register_static(&char_pty_type_info);
 295 }
 296
 297 type_init(register_types);
 298
 299 #endif