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