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