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/option.h"
  33 #include "qemu/qemu-print.h"
  34
  35 #include "chardev/char-io.h"
  36 #include "qom/object.h"
  37
  38 struct PtyChardev {
  39     Chardev parent;
  40     QIOChannel *ioc;
  41     int read_bytes;
  42
  43     int connected;
  44     GSource *timer_src;
  45     char *path;
  46 };
  47 typedef struct PtyChardev PtyChardev;
  48
  49 DECLARE_INSTANCE_CHECKER(PtyChardev, PTY_CHARDEV,
  50                          TYPE_CHARDEV_PTY)
  51
  52 static void pty_chr_state(Chardev *chr, int connected);
  53
  54 static void pty_chr_timer_cancel(PtyChardev *s)
  55 {
  56     if (s->timer_src) {
  57         g_source_destroy(s->timer_src);
  58         g_source_unref(s->timer_src);
  59         s->timer_src = NULL;
  60     }
  61 }
  62
  63 static gboolean pty_chr_timer(gpointer opaque)
  64 {
  65     struct Chardev *chr = CHARDEV(opaque);
  66     PtyChardev *s = PTY_CHARDEV(opaque);
  67
  68     pty_chr_timer_cancel(s);
  69     if (!s->connected) {
  70         /* Next poll ... */
  71         qemu_chr_be_update_read_handlers(chr, chr->gcontext);
  72     }
  73     return FALSE;
  74 }
  75
  76 static void pty_chr_rearm_timer(Chardev *chr, int ms)
  77 {
  78     PtyChardev *s = PTY_CHARDEV(chr);
  79     char *name;
  80
  81     pty_chr_timer_cancel(s);
  82     name = g_strdup_printf("pty-timer-%s", chr->label);
  83     s->timer_src = qemu_chr_timeout_add_ms(chr, ms, pty_chr_timer, chr);
  84     g_source_set_name(s->timer_src, name);
  85     g_free(name);
  86 }
  87
  88 static void pty_chr_update_read_handler(Chardev *chr)
  89 {
  90     PtyChardev *s = PTY_CHARDEV(chr);
  91     GPollFD pfd;
  92     int rc;
  93     QIOChannelFile *fioc = QIO_CHANNEL_FILE(s->ioc);
  94
  95     pfd.fd = fioc->fd;
  96     pfd.events = G_IO_OUT;
  97     pfd.revents = 0;
  98     rc = RETRY_ON_EINTR(g_poll(&pfd, 1, 0));
  99     assert(rc >= 0);
 100
 101     if (pfd.revents & G_IO_HUP) {
 102         pty_chr_state(chr, 0);
 103     } else {
 104         pty_chr_state(chr, 1);
 105     }
 106 }
 107
 108 static int char_pty_chr_write(Chardev *chr, const uint8_t *buf, int len)
 109 {
 110     PtyChardev *s = PTY_CHARDEV(chr);
 111     GPollFD pfd;
 112     int rc;
 113
 114     if (s->connected) {
 115         return io_channel_send(s->ioc, buf, len);
 116     }
 117
 118     /*
 119      * The other side might already be re-connected, but the timer might
 120      * not have fired yet. So let's check here whether we can write again:
 121      */
 122     pfd.fd = QIO_CHANNEL_FILE(s->ioc)->fd;
 123     pfd.events = G_IO_OUT;
 124     pfd.revents = 0;
 125     rc = RETRY_ON_EINTR(g_poll(&pfd, 1, 0));
 126     g_assert(rc >= 0);
 127     if (!(pfd.revents & G_IO_HUP) && (pfd.revents & G_IO_OUT)) {
 128         io_channel_send(s->ioc, buf, len);
 129     }
 130
 131     return len;
 132 }
 133
 134 static GSource *pty_chr_add_watch(Chardev *chr, GIOCondition cond)
 135 {
 136     PtyChardev *s = PTY_CHARDEV(chr);
 137     if (!s->connected) {
 138         return NULL;
 139     }
 140     return qio_channel_create_watch(s->ioc, cond);
 141 }
 142
 143 static int pty_chr_read_poll(void *opaque)
 144 {
 145     Chardev *chr = CHARDEV(opaque);
 146     PtyChardev *s = PTY_CHARDEV(opaque);
 147
 148     s->read_bytes = qemu_chr_be_can_write(chr);
 149     return s->read_bytes;
 150 }
 151
 152 static gboolean pty_chr_read(QIOChannel *chan, GIOCondition cond, void *opaque)
 153 {
 154     Chardev *chr = CHARDEV(opaque);
 155     PtyChardev *s = PTY_CHARDEV(opaque);
 156     gsize len;
 157     uint8_t buf[CHR_READ_BUF_LEN];
 158     ssize_t ret;
 159
 160     len = sizeof(buf);
 161     if (len > s->read_bytes) {
 162         len = s->read_bytes;
 163     }
 164     if (len == 0) {
 165         return TRUE;
 166     }
 167     ret = qio_channel_read(s->ioc, (char *)buf, len, NULL);
 168     if (ret <= 0) {
 169         pty_chr_state(chr, 0);
 170         return FALSE;
 171     } else {
 172         pty_chr_state(chr, 1);
 173         qemu_chr_be_write(chr, buf, ret);
 174     }
 175     return TRUE;
 176 }
 177
 178 static void pty_chr_state(Chardev *chr, int connected)
 179 {
 180     PtyChardev *s = PTY_CHARDEV(chr);
 181
 182     if (!connected) {
 183         remove_fd_in_watch(chr);
 184         s->connected = 0;
 185         /* (re-)connect poll interval for idle guests: once per second.
 186          * We check more frequently in case the guests sends data to
 187          * the virtual device linked to our pty. */
 188         pty_chr_rearm_timer(chr, 1000);
 189     } else {
 190         pty_chr_timer_cancel(s);
 191         if (!s->connected) {
 192             s->connected = 1;
 193             qemu_chr_be_event(chr, CHR_EVENT_OPENED);
 194         }
 195         if (!chr->gsource) {
 196             chr->gsource = io_add_watch_poll(chr, s->ioc,
 197                                                pty_chr_read_poll,
 198                                                pty_chr_read,
 199                                                chr, chr->gcontext);
 200         }
 201     }
 202 }
 203
 204 static void char_pty_finalize(Object *obj)
 205 {
 206     Chardev *chr = CHARDEV(obj);
 207     PtyChardev *s = PTY_CHARDEV(obj);
 208
 209     /* unlink symlink */
 210     if (s->path) {
 211         unlink(s->path);
 212         g_free(s->path);
 213     }
 214
 215     pty_chr_state(chr, 0);
 216     object_unref(OBJECT(s->ioc));
 217     pty_chr_timer_cancel(s);
 218     qemu_chr_be_event(chr, CHR_EVENT_CLOSED);
 219 }
 220
 221 #if defined HAVE_PTY_H
 222 # include <pty.h>
 223 #elif defined CONFIG_BSD
 224 # include <termios.h>
 225 # if defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__DragonFly__)
 226 #  include <libutil.h>
 227 # else
 228 #  include <util.h>
 229 # endif
 230 #elif defined CONFIG_SOLARIS
 231 # include <termios.h>
 232 # include <stropts.h>
 233 #else
 234 # include <termios.h>
 235 #endif
 236
 237 #ifdef __sun__
 238
 239 #if !defined(HAVE_OPENPTY)
 240 /* Once illumos has openpty(), this is going to be removed. */
 241 static int openpty(int *amaster, int *aslave, char *name,
 242                    struct termios *termp, struct winsize *winp)
 243 {
 244     const char *slave;
 245     int mfd = -1, sfd = -1;
 246
 247     *amaster = *aslave = -1;
 248
 249     mfd = open("/dev/ptmx", O_RDWR | O_NOCTTY);
 250     if (mfd < 0) {
 251         goto err;
 252     }
 253
 254     if (grantpt(mfd) == -1 || unlockpt(mfd) == -1) {
 255         goto err;
 256     }
 257
 258     if ((slave = ptsname(mfd)) == NULL) {
 259         goto err;
 260     }
 261
 262     if ((sfd = open(slave, O_RDONLY | O_NOCTTY)) == -1) {
 263         goto err;
 264     }
 265
 266     if (ioctl(sfd, I_PUSH, "ptem") == -1 ||
 267         (termp != NULL && tcgetattr(sfd, termp) < 0)) {
 268         goto err;
 269     }
 270
 271     *amaster = mfd;
 272     *aslave = sfd;
 273
 274     if (winp) {
 275         ioctl(sfd, TIOCSWINSZ, winp);
 276     }
 277
 278     return 0;
 279
 280 err:
 281     if (sfd != -1) {
 282         close(sfd);
 283     }
 284     close(mfd);
 285     return -1;
 286 }
 287 #endif
 288
 289 static void cfmakeraw (struct termios *termios_p)
 290 {
 291     termios_p->c_iflag &=
 292         ~(IGNBRK | BRKINT | PARMRK | ISTRIP | INLCR | IGNCR | ICRNL | IXON);
 293     termios_p->c_oflag &= ~OPOST;
 294     termios_p->c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);
 295     termios_p->c_cflag &= ~(CSIZE | PARENB);
 296     termios_p->c_cflag |= CS8;
 297
 298     termios_p->c_cc[VMIN] = 0;
 299     termios_p->c_cc[VTIME] = 0;
 300 }
 301 #endif
 302
 303 /* like openpty() but also makes it raw; return master fd */
 304 static int qemu_openpty_raw(int *aslave, char *pty_name)
 305 {
 306     int amaster;
 307     struct termios tty;
 308 #if defined(__OpenBSD__) || defined(__DragonFly__)
 309     char pty_buf[PATH_MAX];
 310 #define q_ptsname(x) pty_buf
 311 #else
 312     char *pty_buf = NULL;
 313 #define q_ptsname(x) ptsname(x)
 314 #endif
 315
 316     if (openpty(&amaster, aslave, pty_buf, NULL, NULL) < 0) {
 317         return -1;
 318     }
 319
 320     /* Set raw attributes on the pty. */
 321     tcgetattr(*aslave, &tty);
 322     cfmakeraw(&tty);
 323     tcsetattr(*aslave, TCSAFLUSH, &tty);
 324
 325     if (pty_name) {
 326         strcpy(pty_name, q_ptsname(amaster));
 327     }
 328
 329     return amaster;
 330 }
 331
 332 static void char_pty_open(Chardev *chr,
 333                           ChardevBackend *backend,
 334                           bool *be_opened,
 335                           Error **errp)
 336 {
 337     PtyChardev *s;
 338     int master_fd, slave_fd;
 339     char pty_name[PATH_MAX];
 340     char *name;
 341     char *path = backend->u.pty.data->path;
 342
 343     master_fd = qemu_openpty_raw(&slave_fd, pty_name);
 344     if (master_fd < 0) {
 345         error_setg_errno(errp, errno, "Failed to create PTY");
 346         return;
 347     }
 348
 349     close(slave_fd);
 350     if (!g_unix_set_fd_nonblocking(master_fd, true, NULL)) {
 351         error_setg_errno(errp, errno, "Failed to set FD nonblocking");
 352         return;
 353     }
 354
 355     chr->filename = g_strdup_printf("pty:%s", pty_name);
 356     qemu_printf("char device redirected to %s (label %s)\n",
 357                 pty_name, chr->label);
 358
 359     s = PTY_CHARDEV(chr);
 360     s->ioc = QIO_CHANNEL(qio_channel_file_new_fd(master_fd));
 361     name = g_strdup_printf("chardev-pty-%s", chr->label);
 362     qio_channel_set_name(s->ioc, name);
 363     g_free(name);
 364     s->timer_src = NULL;
 365     *be_opened = false;
 366
 367     /* create symbolic link */
 368     if (path) {
 369         int res = symlink(pty_name, path);
 370
 371         if (res != 0) {
 372             error_setg_errno(errp, errno, "Failed to create PTY symlink");
 373         } else {
 374             s->path = g_strdup(path);
 375         }
 376     }
 377 }
 378
 379 static void char_pty_parse(QemuOpts *opts, ChardevBackend *backend,
 380                            Error **errp)
 381 {
 382     const char *path = qemu_opt_get(opts, "path");
 383     ChardevPty *pty;
 384
 385     backend->type = CHARDEV_BACKEND_KIND_PTY;
 386     pty = backend->u.pty.data = g_new0(ChardevPty, 1);
 387     qemu_chr_parse_common(opts, qapi_ChardevPty_base(pty));
 388     pty->path = g_strdup(path);
 389 }
 390
 391 static void char_pty_class_init(ObjectClass *oc, void *data)
 392 {
 393     ChardevClass *cc = CHARDEV_CLASS(oc);
 394
 395     cc->parse = char_pty_parse;
 396     cc->open = char_pty_open;
 397     cc->chr_write = char_pty_chr_write;
 398     cc->chr_update_read_handler = pty_chr_update_read_handler;
 399     cc->chr_add_watch = pty_chr_add_watch;
 400 }
 401
 402 static const TypeInfo char_pty_type_info = {
 403     .name = TYPE_CHARDEV_PTY,
 404     .parent = TYPE_CHARDEV,
 405     .instance_size = sizeof(PtyChardev),
 406     .instance_finalize = char_pty_finalize,
 407     .class_init = char_pty_class_init,
 408 };
 409
 410 static void register_types(void)
 411 {
 412     type_register_static(&char_pty_type_info);
 413 }
 414
 415 type_init(register_types);