chardev/char-mux.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 "qemu/module.h"
  28 #include "qemu/option.h"
  29 #include "chardev/char.h"
  30 #include "sysemu/block-backend.h"
  31 #include "qapi/qapi-commands-control.h"
  32 #include "chardev-internal.h"
  33
  34 /* MUX driver for serial I/O splitting */
  35
  36 /*
  37  * Set to false by suspend_mux_open.  Open events are delayed until
  38  * resume_mux_open.  Usually suspend_mux_open is called before
  39  * command line processing and resume_mux_open afterwards.
  40  */
  41 static bool muxes_opened = true;
  42
  43 /* Called with chr_write_lock held.  */
  44 static int mux_chr_write(Chardev *chr, const uint8_t *buf, int len)
  45 {
  46     MuxChardev *d = MUX_CHARDEV(chr);
  47     int ret;
  48     if (!d->timestamps) {
  49         ret = qemu_chr_fe_write(&d->chr, buf, len);
  50     } else {
  51         int i;
  52
  53         ret = 0;
  54         for (i = 0; i < len; i++) {
  55             if (d->linestart) {
  56                 char buf1[64];
  57                 int64_t ti;
  58                 int secs;
  59
  60                 ti = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
  61                 if (d->timestamps_start == -1) {
  62                     d->timestamps_start = ti;
  63                 }
  64                 ti -= d->timestamps_start;
  65                 secs = ti / 1000;
  66                 snprintf(buf1, sizeof(buf1),
  67                          "[%02d:%02d:%02d.%03d] ",
  68                          secs / 3600,
  69                          (secs / 60) % 60,
  70                          secs % 60,
  71                          (int)(ti % 1000));
  72                 /* XXX this blocks entire thread. Rewrite to use
  73                  * qemu_chr_fe_write and background I/O callbacks */
  74                 qemu_chr_fe_write_all(&d->chr,
  75                                       (uint8_t *)buf1, strlen(buf1));
  76                 d->linestart = 0;
  77             }
  78             ret += qemu_chr_fe_write(&d->chr, buf + i, 1);
  79             if (buf[i] == '\n') {
  80                 d->linestart = 1;
  81             }
  82         }
  83     }
  84     return ret;
  85 }
  86
  87 static const char * const mux_help[] = {
  88     "% h    print this help\n\r",
  89     "% x    exit emulator\n\r",
  90     "% s    save disk data back to file (if -snapshot)\n\r",
  91     "% t    toggle console timestamps\n\r",
  92     "% b    send break (magic sysrq)\n\r",
  93     "% c    switch between console and monitor\n\r",
  94     "% %  sends %\n\r",
  95     NULL
  96 };
  97
  98 int term_escape_char = 0x01; /* ctrl-a is used for escape */
  99 static void mux_print_help(Chardev *chr)
 100 {
 101     int i, j;
 102     char ebuf[15] = "Escape-Char";
 103     char cbuf[50] = "\n\r";
 104
 105     if (term_escape_char > 0 && term_escape_char < 26) {
 106         snprintf(cbuf, sizeof(cbuf), "\n\r");
 107         snprintf(ebuf, sizeof(ebuf), "C-%c", term_escape_char - 1 + 'a');
 108     } else {
 109         snprintf(cbuf, sizeof(cbuf),
 110                  "\n\rEscape-Char set to Ascii: 0x%02x\n\r\n\r",
 111                  term_escape_char);
 112     }
 113     /* XXX this blocks entire thread. Rewrite to use
 114      * qemu_chr_fe_write and background I/O callbacks */
 115     qemu_chr_write_all(chr, (uint8_t *)cbuf, strlen(cbuf));
 116     for (i = 0; mux_help[i] != NULL; i++) {
 117         for (j = 0; mux_help[i][j] != '\0'; j++) {
 118             if (mux_help[i][j] == '%') {
 119                 qemu_chr_write_all(chr, (uint8_t *)ebuf, strlen(ebuf));
 120             } else {
 121                 qemu_chr_write_all(chr, (uint8_t *)&mux_help[i][j], 1);
 122             }
 123         }
 124     }
 125 }
 126
 127 static void mux_chr_send_event(MuxChardev *d, int mux_nr, QEMUChrEvent event)
 128 {
 129     CharBackend *be = d->backends[mux_nr];
 130
 131     if (be && be->chr_event) {
 132         be->chr_event(be->opaque, event);
 133     }
 134 }
 135
 136 static void mux_chr_be_event(Chardev *chr, QEMUChrEvent event)
 137 {
 138     MuxChardev *d = MUX_CHARDEV(chr);
 139
 140     if (d->focus != -1) {
 141         mux_chr_send_event(d, d->focus, event);
 142     }
 143 }
 144
 145 static int mux_proc_byte(Chardev *chr, MuxChardev *d, int ch)
 146 {
 147     if (d->term_got_escape) {
 148         d->term_got_escape = 0;
 149         if (ch == term_escape_char) {
 150             goto send_char;
 151         }
 152         switch (ch) {
 153         case '?':
 154         case 'h':
 155             mux_print_help(chr);
 156             break;
 157         case 'x':
 158             {
 159                  const char *term =  "QEMU: Terminated\n\r";
 160                  qemu_chr_write_all(chr, (uint8_t *)term, strlen(term));
 161                  qmp_quit(NULL);
 162                  break;
 163             }
 164         case 's':
 165             blk_commit_all();
 166             break;
 167         case 'b':
 168             qemu_chr_be_event(chr, CHR_EVENT_BREAK);
 169             break;
 170         case 'c':
 171             assert(d->mux_cnt > 0); /* handler registered with first fe */
 172             /* Switch to the next registered device */
 173             mux_set_focus(chr, (d->focus + 1) % d->mux_cnt);
 174             break;
 175         case 't':
 176             d->timestamps = !d->timestamps;
 177             d->timestamps_start = -1;
 178             d->linestart = 0;
 179             break;
 180         }
 181     } else if (ch == term_escape_char) {
 182         d->term_got_escape = 1;
 183     } else {
 184     send_char:
 185         return 1;
 186     }
 187     return 0;
 188 }
 189
 190 static void mux_chr_accept_input(Chardev *chr)
 191 {
 192     MuxChardev *d = MUX_CHARDEV(chr);
 193     int m = d->focus;
 194     CharBackend *be = d->backends[m];
 195
 196     while (be && d->prod[m] != d->cons[m] &&
 197            be->chr_can_read && be->chr_can_read(be->opaque)) {
 198         be->chr_read(be->opaque,
 199                      &d->buffer[m][d->cons[m]++ & MUX_BUFFER_MASK], 1);
 200     }
 201 }
 202
 203 static int mux_chr_can_read(void *opaque)
 204 {
 205     MuxChardev *d = MUX_CHARDEV(opaque);
 206     int m = d->focus;
 207     CharBackend *be = d->backends[m];
 208
 209     if ((d->prod[m] - d->cons[m]) < MUX_BUFFER_SIZE) {
 210         return 1;
 211     }
 212
 213     if (be && be->chr_can_read) {
 214         return be->chr_can_read(be->opaque);
 215     }
 216
 217     return 0;
 218 }
 219
 220 static void mux_chr_read(void *opaque, const uint8_t *buf, int size)
 221 {
 222     Chardev *chr = CHARDEV(opaque);
 223     MuxChardev *d = MUX_CHARDEV(opaque);
 224     int m = d->focus;
 225     CharBackend *be = d->backends[m];
 226     int i;
 227
 228     mux_chr_accept_input(opaque);
 229
 230     for (i = 0; i < size; i++)
 231         if (mux_proc_byte(chr, d, buf[i])) {
 232             if (d->prod[m] == d->cons[m] &&
 233                 be && be->chr_can_read &&
 234                 be->chr_can_read(be->opaque)) {
 235                 be->chr_read(be->opaque, &buf[i], 1);
 236             } else {
 237                 d->buffer[m][d->prod[m]++ & MUX_BUFFER_MASK] = buf[i];
 238             }
 239         }
 240 }
 241
 242 void mux_chr_send_all_event(Chardev *chr, QEMUChrEvent event)
 243 {
 244     MuxChardev *d = MUX_CHARDEV(chr);
 245     int i;
 246
 247     if (!muxes_opened) {
 248         return;
 249     }
 250
 251     /* Send the event to all registered listeners */
 252     for (i = 0; i < d->mux_cnt; i++) {
 253         mux_chr_send_event(d, i, event);
 254     }
 255 }
 256
 257 static void mux_chr_event(void *opaque, QEMUChrEvent event)
 258 {
 259     mux_chr_send_all_event(CHARDEV(opaque), event);
 260 }
 261
 262 static GSource *mux_chr_add_watch(Chardev *s, GIOCondition cond)
 263 {
 264     MuxChardev *d = MUX_CHARDEV(s);
 265     Chardev *chr = qemu_chr_fe_get_driver(&d->chr);
 266     ChardevClass *cc = CHARDEV_GET_CLASS(chr);
 267
 268     if (!cc->chr_add_watch) {
 269         return NULL;
 270     }
 271
 272     return cc->chr_add_watch(chr, cond);
 273 }
 274
 275 static void char_mux_finalize(Object *obj)
 276 {
 277     MuxChardev *d = MUX_CHARDEV(obj);
 278     int i;
 279
 280     for (i = 0; i < d->mux_cnt; i++) {
 281         CharBackend *be = d->backends[i];
 282         if (be) {
 283             be->chr = NULL;
 284         }
 285     }
 286     qemu_chr_fe_deinit(&d->chr, false);
 287 }
 288
 289 static void mux_chr_update_read_handlers(Chardev *chr)
 290 {
 291     MuxChardev *d = MUX_CHARDEV(chr);
 292
 293     /* Fix up the real driver with mux routines */
 294     qemu_chr_fe_set_handlers_full(&d->chr,
 295                                   mux_chr_can_read,
 296                                   mux_chr_read,
 297                                   mux_chr_event,
 298                                   NULL,
 299                                   chr,
 300                                   chr->gcontext, true, false);
 301 }
 302
 303 void mux_set_focus(Chardev *chr, int focus)
 304 {
 305     MuxChardev *d = MUX_CHARDEV(chr);
 306
 307     assert(focus >= 0);
 308     assert(focus < d->mux_cnt);
 309
 310     if (d->focus != -1) {
 311         mux_chr_send_event(d, d->focus, CHR_EVENT_MUX_OUT);
 312     }
 313
 314     d->focus = focus;
 315     chr->be = d->backends[focus];
 316     mux_chr_send_event(d, d->focus, CHR_EVENT_MUX_IN);
 317 }
 318
 319 static void qemu_chr_open_mux(Chardev *chr,
 320                               ChardevBackend *backend,
 321                               bool *be_opened,
 322                               Error **errp)
 323 {
 324     ChardevMux *mux = backend->u.mux.data;
 325     Chardev *drv;
 326     MuxChardev *d = MUX_CHARDEV(chr);
 327
 328     drv = qemu_chr_find(mux->chardev);
 329     if (drv == NULL) {
 330         error_setg(errp, "mux: base chardev %s not found", mux->chardev);
 331         return;
 332     }
 333
 334     d->focus = -1;
 335     /* only default to opened state if we've realized the initial
 336      * set of muxes
 337      */
 338     *be_opened = muxes_opened;
 339     qemu_chr_fe_init(&d->chr, drv, errp);
 340 }
 341
 342 static void qemu_chr_parse_mux(QemuOpts *opts, ChardevBackend *backend,
 343                                Error **errp)
 344 {
 345     const char *chardev = qemu_opt_get(opts, "chardev");
 346     ChardevMux *mux;
 347
 348     if (chardev == NULL) {
 349         error_setg(errp, "chardev: mux: no chardev given");
 350         return;
 351     }
 352     backend->type = CHARDEV_BACKEND_KIND_MUX;
 353     mux = backend->u.mux.data = g_new0(ChardevMux, 1);
 354     qemu_chr_parse_common(opts, qapi_ChardevMux_base(mux));
 355     mux->chardev = g_strdup(chardev);
 356 }
 357
 358 /**
 359  * Called after processing of default and command-line-specified
 360  * chardevs to deliver CHR_EVENT_OPENED events to any FEs attached
 361  * to a mux chardev. This is done here to ensure that
 362  * output/prompts/banners are only displayed for the FE that has
 363  * focus when initial command-line processing/machine init is
 364  * completed.
 365  *
 366  * After this point, any new FE attached to any new or existing
 367  * mux will receive CHR_EVENT_OPENED notifications for the BE
 368  * immediately.
 369  */
 370 static void open_muxes(Chardev *chr)
 371 {
 372     /* send OPENED to all already-attached FEs */
 373     mux_chr_send_all_event(chr, CHR_EVENT_OPENED);
 374
 375     /*
 376      * mark mux as OPENED so any new FEs will immediately receive
 377      * OPENED event
 378      */
 379     chr->be_open = 1;
 380 }
 381
 382 void suspend_mux_open(void)
 383 {
 384     muxes_opened = false;
 385 }
 386
 387 static int chardev_options_parsed_cb(Object *child, void *opaque)
 388 {
 389     Chardev *chr = (Chardev *)child;
 390
 391     if (!chr->be_open && CHARDEV_IS_MUX(chr)) {
 392         open_muxes(chr);
 393     }
 394
 395     return 0;
 396 }
 397
 398 void resume_mux_open(void)
 399 {
 400     muxes_opened = true;
 401     object_child_foreach(get_chardevs_root(),
 402                          chardev_options_parsed_cb, NULL);
 403 }
 404
 405 static void char_mux_class_init(ObjectClass *oc, void *data)
 406 {
 407     ChardevClass *cc = CHARDEV_CLASS(oc);
 408
 409     cc->parse = qemu_chr_parse_mux;
 410     cc->open = qemu_chr_open_mux;
 411     cc->chr_write = mux_chr_write;
 412     cc->chr_accept_input = mux_chr_accept_input;
 413     cc->chr_add_watch = mux_chr_add_watch;
 414     cc->chr_be_event = mux_chr_be_event;
 415     cc->chr_update_read_handler = mux_chr_update_read_handlers;
 416 }
 417
 418 static const TypeInfo char_mux_type_info = {
 419     .name = TYPE_CHARDEV_MUX,
 420     .parent = TYPE_CHARDEV,
 421     .class_init = char_mux_class_init,
 422     .instance_size = sizeof(MuxChardev),
 423     .instance_finalize = char_mux_finalize,
 424 };
 425
 426 static void register_types(void)
 427 {
 428     type_register_static(&char_mux_type_info);
 429 }
 430
 431 type_init(register_types);