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 "qapi/error.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/module.h"
  32 #include "qemu/qemu-print.h"
  33
  34 #include "chardev/char-io.h"
  35 #include "qom/object.h"
  36
  37 struct PtyChardev {
  38     Chardev parent;
  39     QIOChannel *ioc;
  40     int read_bytes;
  41
  42     int connected;
  43     GSource *timer_src;
  44 };
  45 typedef struct PtyChardev PtyChardev;
  46
  47 DECLARE_INSTANCE_CHECKER(PtyChardev, PTY_CHARDEV,
  48                          TYPE_CHARDEV_PTY)
  49
  50 static void pty_chr_state(Chardev *chr, int connected);
  51
  52 static void pty_chr_timer_cancel(PtyChardev *s)
  53 {
  54     if (s->timer_src) {
  55         g_source_destroy(s->timer_src);
  56         g_source_unref(s->timer_src);
  57         s->timer_src = NULL;
  58     }
  59 }
  60
  61 static gboolean pty_chr_timer(gpointer opaque)
  62 {
  63     struct Chardev *chr = CHARDEV(opaque);
  64     PtyChardev *s = PTY_CHARDEV(opaque);
  65
  66     pty_chr_timer_cancel(s);
  67     if (!s->connected) {
  68         /* Next poll ... */
  69         qemu_chr_be_update_read_handlers(chr, chr->gcontext);
  70     }
  71     return FALSE;
  72 }
  73
  74 static void pty_chr_rearm_timer(Chardev *chr, int ms)
  75 {
  76     PtyChardev *s = PTY_CHARDEV(chr);
  77     char *name;
  78
  79     pty_chr_timer_cancel(s);
  80     name = g_strdup_printf("pty-timer-%s", chr->label);
  81     s->timer_src = qemu_chr_timeout_add_ms(chr, ms, pty_chr_timer, chr);
  82     g_source_set_name(s->timer_src, name);
  83     g_free(name);
  84 }
  85
  86 static void pty_chr_update_read_handler(Chardev *chr)
  87 {
  88     PtyChardev *s = PTY_CHARDEV(chr);
  89     GPollFD pfd;
  90     int rc;
  91     QIOChannelFile *fioc = QIO_CHANNEL_FILE(s->ioc);
  92
  93     pfd.fd = fioc->fd;
  94     pfd.events = G_IO_OUT;
  95     pfd.revents = 0;
  96     rc = RETRY_ON_EINTR(g_poll(&pfd, 1, 0));
  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     GPollFD pfd;
 110     int rc;
 111
 112     if (s->connected) {
 113         return io_channel_send(s->ioc, buf, len);
 114     }
 115
 116     /*
 117      * The other side might already be re-connected, but the timer might
 118      * not have fired yet. So let's check here whether we can write again:
 119      */
 120     pfd.fd = QIO_CHANNEL_FILE(s->ioc)->fd;
 121     pfd.events = G_IO_OUT;
 122     pfd.revents = 0;
 123     rc = RETRY_ON_EINTR(g_poll(&pfd, 1, 0));
 124     g_assert(rc >= 0);
 125     if (!(pfd.revents & G_IO_HUP) && (pfd.revents & G_IO_OUT)) {
 126         io_channel_send(s->ioc, buf, len);
 127     }
 128
 129     return len;
 130 }
 131
 132 static GSource *pty_chr_add_watch(Chardev *chr, GIOCondition cond)
 133 {
 134     PtyChardev *s = PTY_CHARDEV(chr);
 135     if (!s->connected) {
 136         return NULL;
 137     }
 138     return qio_channel_create_watch(s->ioc, cond);
 139 }
 140
 141 static int pty_chr_read_poll(void *opaque)
 142 {
 143     Chardev *chr = CHARDEV(opaque);
 144     PtyChardev *s = PTY_CHARDEV(opaque);
 145
 146     s->read_bytes = qemu_chr_be_can_write(chr);
 147     return s->read_bytes;
 148 }
 149
 150 static gboolean pty_chr_read(QIOChannel *chan, GIOCondition cond, void *opaque)
 151 {
 152     Chardev *chr = CHARDEV(opaque);
 153     PtyChardev *s = PTY_CHARDEV(opaque);
 154     gsize len;
 155     uint8_t buf[CHR_READ_BUF_LEN];
 156     ssize_t ret;
 157
 158     len = sizeof(buf);
 159     if (len > s->read_bytes) {
 160         len = s->read_bytes;
 161     }
 162     if (len == 0) {
 163         return TRUE;
 164     }
 165     ret = qio_channel_read(s->ioc, (char *)buf, len, NULL);
 166     if (ret <= 0) {
 167         pty_chr_state(chr, 0);
 168         return FALSE;
 169     } else {
 170         pty_chr_state(chr, 1);
 171         qemu_chr_be_write(chr, buf, ret);
 172     }
 173     return TRUE;
 174 }
 175
 176 static void pty_chr_state(Chardev *chr, int connected)
 177 {
 178     PtyChardev *s = PTY_CHARDEV(chr);
 179
 180     if (!connected) {
 181         remove_fd_in_watch(chr);
 182         s->connected = 0;
 183         /* (re-)connect poll interval for idle guests: once per second.
 184          * We check more frequently in case the guests sends data to
 185          * the virtual device linked to our pty. */
 186         pty_chr_rearm_timer(chr, 1000);
 187     } else {
 188         pty_chr_timer_cancel(s);
 189         if (!s->connected) {
 190             s->connected = 1;
 191             qemu_chr_be_event(chr, CHR_EVENT_OPENED);
 192         }
 193         if (!chr->gsource) {
 194             chr->gsource = io_add_watch_poll(chr, s->ioc,
 195                                                pty_chr_read_poll,
 196                                                pty_chr_read,
 197                                                chr, chr->gcontext);
 198         }
 199     }
 200 }
 201
 202 static void char_pty_finalize(Object *obj)
 203 {
 204     Chardev *chr = CHARDEV(obj);
 205     PtyChardev *s = PTY_CHARDEV(obj);
 206
 207     pty_chr_state(chr, 0);
 208     object_unref(OBJECT(s->ioc));
 209     pty_chr_timer_cancel(s);
 210     qemu_chr_be_event(chr, CHR_EVENT_CLOSED);
 211 }
 212
 213 #if defined HAVE_PTY_H
 214 # include <pty.h>
 215 #elif defined CONFIG_BSD
 216 # include <termios.h>
 217 # if defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__DragonFly__)
 218 #  include <libutil.h>
 219 # else
 220 #  include <util.h>
 221 # endif
 222 #elif defined CONFIG_SOLARIS
 223 # include <termios.h>
 224 # include <stropts.h>
 225 #else
 226 # include <termios.h>
 227 #endif
 228
 229 #ifdef __sun__
 230
 231 #if !defined(HAVE_OPENPTY)
 232 /* Once illumos has openpty(), this is going to be removed. */
 233 static int openpty(int *amaster, int *aslave, char *name,
 234                    struct termios *termp, struct winsize *winp)
 235 {
 236     const char *slave;
 237     int mfd = -1, sfd = -1;
 238
 239     *amaster = *aslave = -1;
 240
 241     mfd = open("/dev/ptmx", O_RDWR | O_NOCTTY);
 242     if (mfd < 0) {
 243         goto err;
 244     }
 245
 246     if (grantpt(mfd) == -1 || unlockpt(mfd) == -1) {
 247         goto err;
 248     }
 249
 250     if ((slave = ptsname(mfd)) == NULL) {
 251         goto err;
 252     }
 253
 254     if ((sfd = open(slave, O_RDONLY | O_NOCTTY)) == -1) {
 255         goto err;
 256     }
 257
 258     if (ioctl(sfd, I_PUSH, "ptem") == -1 ||
 259         (termp != NULL && tcgetattr(sfd, termp) < 0)) {
 260         goto err;
 261     }
 262
 263     *amaster = mfd;
 264     *aslave = sfd;
 265
 266     if (winp) {
 267         ioctl(sfd, TIOCSWINSZ, winp);
 268     }
 269
 270     return 0;
 271
 272 err:
 273     if (sfd != -1) {
 274         close(sfd);
 275     }
 276     close(mfd);
 277     return -1;
 278 }
 279 #endif
 280
 281 static void cfmakeraw (struct termios *termios_p)
 282 {
 283     termios_p->c_iflag &=
 284         ~(IGNBRK | BRKINT | PARMRK | ISTRIP | INLCR | IGNCR | ICRNL | IXON);
 285     termios_p->c_oflag &= ~OPOST;
 286     termios_p->c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);
 287     termios_p->c_cflag &= ~(CSIZE | PARENB);
 288     termios_p->c_cflag |= CS8;
 289
 290     termios_p->c_cc[VMIN] = 0;
 291     termios_p->c_cc[VTIME] = 0;
 292 }
 293 #endif
 294
 295 /* like openpty() but also makes it raw; return master fd */
 296 static int qemu_openpty_raw(int *aslave, char *pty_name)
 297 {
 298     int amaster;
 299     struct termios tty;
 300 #if defined(__OpenBSD__) || defined(__DragonFly__)
 301     char pty_buf[PATH_MAX];
 302 #define q_ptsname(x) pty_buf
 303 #else
 304     char *pty_buf = NULL;
 305 #define q_ptsname(x) ptsname(x)
 306 #endif
 307
 308     if (openpty(&amaster, aslave, pty_buf, NULL, NULL) < 0) {
 309         return -1;
 310     }
 311
 312     /* Set raw attributes on the pty. */
 313     tcgetattr(*aslave, &tty);
 314     cfmakeraw(&tty);
 315     tcsetattr(*aslave, TCSAFLUSH, &tty);
 316
 317     if (pty_name) {
 318         strcpy(pty_name, q_ptsname(amaster));
 319     }
 320
 321     return amaster;
 322 }
 323
 324 static void char_pty_open(Chardev *chr,
 325                           ChardevBackend *backend,
 326                           bool *be_opened,
 327                           Error **errp)
 328 {
 329     PtyChardev *s;
 330     int master_fd, slave_fd;
 331     char pty_name[PATH_MAX];
 332     char *name;
 333
 334     master_fd = qemu_openpty_raw(&slave_fd, pty_name);
 335     if (master_fd < 0) {
 336         error_setg_errno(errp, errno, "Failed to create PTY");
 337         return;
 338     }
 339
 340     close(slave_fd);
 341     if (!g_unix_set_fd_nonblocking(master_fd, true, NULL)) {
 342         error_setg_errno(errp, errno, "Failed to set FD nonblocking");
 343         return;
 344     }
 345
 346     chr->filename = g_strdup_printf("pty:%s", pty_name);
 347     qemu_printf("char device redirected to %s (label %s)\n",
 348                 pty_name, chr->label);
 349
 350     s = PTY_CHARDEV(chr);
 351     s->ioc = QIO_CHANNEL(qio_channel_file_new_fd(master_fd));
 352     name = g_strdup_printf("chardev-pty-%s", chr->label);
 353     qio_channel_set_name(s->ioc, name);
 354     g_free(name);
 355     s->timer_src = NULL;
 356     *be_opened = false;
 357 }
 358
 359 static void char_pty_class_init(ObjectClass *oc, void *data)
 360 {
 361     ChardevClass *cc = CHARDEV_CLASS(oc);
 362
 363     cc->open = char_pty_open;
 364     cc->chr_write = char_pty_chr_write;
 365     cc->chr_update_read_handler = pty_chr_update_read_handler;
 366     cc->chr_add_watch = pty_chr_add_watch;
 367 }
 368
 369 static const TypeInfo char_pty_type_info = {
 370     .name = TYPE_CHARDEV_PTY,
 371     .parent = TYPE_CHARDEV,
 372     .instance_size = sizeof(PtyChardev),
 373     .instance_finalize = char_pty_finalize,
 374     .class_init = char_pty_class_init,
 375 };
 376
 377 static void register_types(void)
 378 {
 379     type_register_static(&char_pty_type_info);
 380 }
 381
 382 type_init(register_types);