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