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     GSource *timer_src;
  46     GSource *open_source;
  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_src = NULL;
  61     g_source_unref(s->open_source);
  62     s->open_source = NULL;
  63     if (!s->connected) {
  64         /* Next poll ... */
  65         pty_chr_update_read_handler_locked(chr);
  66     }
  67     qemu_mutex_unlock(&chr->chr_write_lock);
  68     return FALSE;
  69 }
  70
  71 static void pty_chr_timer_cancel(PtyChardev *s)
  72 {
  73     if (s->timer_src) {
  74         g_source_destroy(s->timer_src);
  75         g_source_unref(s->timer_src);
  76         s->timer_src = NULL;
  77     }
  78 }
  79
  80 /* Called with chr_write_lock held.  */
  81 static void pty_chr_rearm_timer(Chardev *chr, int ms)
  82 {
  83     PtyChardev *s = PTY_CHARDEV(chr);
  84     char *name;
  85
  86     pty_chr_timer_cancel(s);
  87     name = g_strdup_printf("pty-timer-%s", chr->label);
  88     s->timer_src = qemu_chr_timeout_add_ms(chr, ms, pty_chr_timer, chr);
  89     g_source_set_name(s->timer_src, name);
  90     g_free(name);
  91 }
  92
  93 /* Called with chr_write_lock held.  */
  94 static void pty_chr_update_read_handler_locked(Chardev *chr)
  95 {
  96     PtyChardev *s = PTY_CHARDEV(chr);
  97     GPollFD pfd;
  98     int rc;
  99     QIOChannelFile *fioc = QIO_CHANNEL_FILE(s->ioc);
 100
 101     pfd.fd = fioc->fd;
 102     pfd.events = G_IO_OUT;
 103     pfd.revents = 0;
 104     do {
 105         rc = g_poll(&pfd, 1, 0);
 106     } while (rc == -1 && errno == EINTR);
 107     assert(rc >= 0);
 108
 109     if (pfd.revents & G_IO_HUP) {
 110         pty_chr_state(chr, 0);
 111     } else {
 112         pty_chr_state(chr, 1);
 113     }
 114 }
 115
 116 static void pty_chr_update_read_handler(Chardev *chr)
 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_source = NULL;
 188     qemu_chr_be_event(chr, CHR_EVENT_OPENED);
 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_source) {
 199             g_source_destroy(s->open_source);
 200             g_source_unref(s->open_source);
 201             s->open_source = NULL;
 202         }
 203         remove_fd_in_watch(chr);
 204         s->connected = 0;
 205         /* (re-)connect poll interval for idle guests: once per second.
 206          * We check more frequently in case the guests sends data to
 207          * the virtual device linked to our pty. */
 208         pty_chr_rearm_timer(chr, 1000);
 209     } else {
 210         pty_chr_timer_cancel(s);
 211         if (!s->connected) {
 212             g_assert(s->open_source == NULL);
 213             s->open_source = g_idle_source_new();
 214             s->connected = 1;
 215             g_source_set_callback(s->open_source,
 216                                   qemu_chr_be_generic_open_func,
 217                                   chr, NULL);
 218             g_source_attach(s->open_source, chr->gcontext);
 219         }
 220         if (!chr->gsource) {
 221             chr->gsource = io_add_watch_poll(chr, s->ioc,
 222                                                pty_chr_read_poll,
 223                                                pty_chr_read,
 224                                                chr, chr->gcontext);
 225         }
 226     }
 227 }
 228
 229 static void char_pty_finalize(Object *obj)
 230 {
 231     Chardev *chr = CHARDEV(obj);
 232     PtyChardev *s = PTY_CHARDEV(obj);
 233
 234     qemu_mutex_lock(&chr->chr_write_lock);
 235     pty_chr_state(chr, 0);
 236     object_unref(OBJECT(s->ioc));
 237     pty_chr_timer_cancel(s);
 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_src = NULL;
 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