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