qemu-ga.c

   1 /*
   2  * QEMU Guest Agent
   3  *
   4  * Copyright IBM Corp. 2011
   5  *
   6  * Authors:
   7  *  Adam Litke        <aglitke@linux.vnet.ibm.com>
   8  *  Michael Roth      <mdroth@linux.vnet.ibm.com>
   9  *
  10  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  11  * See the COPYING file in the top-level directory.
  12  */
  13 #include <stdlib.h>
  14 #include <stdio.h>
  15 #include <stdbool.h>
  16 #include <glib.h>
  17 #include <getopt.h>
  18 #include <termios.h>
  19 #include <syslog.h>
  20 #include "qemu_socket.h"
  21 #include "json-streamer.h"
  22 #include "json-parser.h"
  23 #include "qint.h"
  24 #include "qjson.h"
  25 #include "qga/guest-agent-core.h"
  26 #include "module.h"
  27 #include "signal.h"
  28 #include "qerror.h"
  29 #include "error_int.h"
  30
  31 #define QGA_VIRTIO_PATH_DEFAULT "/dev/virtio-ports/org.qemu.guest_agent.0"
  32 #define QGA_PIDFILE_DEFAULT "/var/run/qemu-ga.pid"
  33 #define QGA_BAUDRATE_DEFAULT B38400 /* for isa-serial channels */
  34 #define QGA_TIMEOUT_DEFAULT 30*1000 /* ms */
  35
  36 struct GAState {
  37     JSONMessageParser parser;
  38     GMainLoop *main_loop;
  39     GIOChannel *conn_channel;
  40     GIOChannel *listen_channel;
  41     const char *path;
  42     const char *method;
  43     bool virtio; /* fastpath to check for virtio to deal with poll() quirks */
  44     GACommandState *command_state;
  45     GLogLevelFlags log_level;
  46     FILE *log_file;
  47     bool logging_enabled;
  48 };
  49
  50 static struct GAState *ga_state;
  51
  52 static void quit_handler(int sig)
  53 {
  54     g_debug("received signal num %d, quitting", sig);
  55
  56     if (g_main_loop_is_running(ga_state->main_loop)) {
  57         g_main_loop_quit(ga_state->main_loop);
  58     }
  59 }
  60
  61 static void register_signal_handlers(void)
  62 {
  63     struct sigaction sigact;
  64     int ret;
  65
  66     memset(&sigact, 0, sizeof(struct sigaction));
  67     sigact.sa_handler = quit_handler;
  68
  69     ret = sigaction(SIGINT, &sigact, NULL);
  70     if (ret == -1) {
  71         g_error("error configuring signal handler: %s", strerror(errno));
  72         exit(EXIT_FAILURE);
  73     }
  74     ret = sigaction(SIGTERM, &sigact, NULL);
  75     if (ret == -1) {
  76         g_error("error configuring signal handler: %s", strerror(errno));
  77     }
  78 }
  79
  80 static void usage(const char *cmd)
  81 {
  82     printf(
  83 "Usage: %s -c <channel_opts>\n"
  84 "QEMU Guest Agent %s\n"
  85 "\n"
  86 "  -m, --method      transport method: one of unix-listen, virtio-serial, or\n"
  87 "                    isa-serial (virtio-serial is the default)\n"
  88 "  -p, --path        device/socket path (%s is the default for virtio-serial)\n"
  89 "  -l, --logfile     set logfile path, logs to stderr by default\n"
  90 "  -f, --pidfile     specify pidfile (default is %s)\n"
  91 "  -v, --verbose     log extra debugging information\n"
  92 "  -V, --version     print version information and exit\n"
  93 "  -d, --daemonize   become a daemon\n"
  94 "  -h, --help        display this help and exit\n"
  95 "\n"
  96 "Report bugs to <mdroth@linux.vnet.ibm.com>\n"
  97     , cmd, QGA_VERSION, QGA_VIRTIO_PATH_DEFAULT, QGA_PIDFILE_DEFAULT);
  98 }
  99
 100 static void conn_channel_close(GAState *s);
 101
 102 static const char *ga_log_level_str(GLogLevelFlags level)
 103 {
 104     switch (level & G_LOG_LEVEL_MASK) {
 105         case G_LOG_LEVEL_ERROR:
 106             return "error";
 107         case G_LOG_LEVEL_CRITICAL:
 108             return "critical";
 109         case G_LOG_LEVEL_WARNING:
 110             return "warning";
 111         case G_LOG_LEVEL_MESSAGE:
 112             return "message";
 113         case G_LOG_LEVEL_INFO:
 114             return "info";
 115         case G_LOG_LEVEL_DEBUG:
 116             return "debug";
 117         default:
 118             return "user";
 119     }
 120 }
 121
 122 bool ga_logging_enabled(GAState *s)
 123 {
 124     return s->logging_enabled;
 125 }
 126
 127 void ga_disable_logging(GAState *s)
 128 {
 129     s->logging_enabled = false;
 130 }
 131
 132 void ga_enable_logging(GAState *s)
 133 {
 134     s->logging_enabled = true;
 135 }
 136
 137 static void ga_log(const gchar *domain, GLogLevelFlags level,
 138                    const gchar *msg, gpointer opaque)
 139 {
 140     GAState *s = opaque;
 141     GTimeVal time;
 142     const char *level_str = ga_log_level_str(level);
 143
 144     if (!ga_logging_enabled(s)) {
 145         return;
 146     }
 147
 148     level &= G_LOG_LEVEL_MASK;
 149     if (domain && strcmp(domain, "syslog") == 0) {
 150         syslog(LOG_INFO, "%s: %s", level_str, msg);
 151     } else if (level & s->log_level) {
 152         g_get_current_time(&time);
 153         fprintf(s->log_file,
 154                 "%lu.%lu: %s: %s\n", time.tv_sec, time.tv_usec, level_str, msg);
 155         fflush(s->log_file);
 156     }
 157 }
 158
 159 static void become_daemon(const char *pidfile)
 160 {
 161     pid_t pid, sid;
 162     int pidfd;
 163     char *pidstr = NULL;
 164
 165     pid = fork();
 166     if (pid < 0) {
 167         exit(EXIT_FAILURE);
 168     }
 169     if (pid > 0) {
 170         exit(EXIT_SUCCESS);
 171     }
 172
 173     pidfd = open(pidfile, O_CREAT|O_WRONLY|O_EXCL, S_IRUSR|S_IWUSR);
 174     if (pidfd == -1) {
 175         g_critical("Cannot create pid file, %s", strerror(errno));
 176         exit(EXIT_FAILURE);
 177     }
 178
 179     if (asprintf(&pidstr, "%d", getpid()) == -1) {
 180         g_critical("Cannot allocate memory");
 181         goto fail;
 182     }
 183     if (write(pidfd, pidstr, strlen(pidstr)) != strlen(pidstr)) {
 184         free(pidstr);
 185         g_critical("Failed to write pid file");
 186         goto fail;
 187     }
 188
 189     umask(0);
 190     sid = setsid();
 191     if (sid < 0) {
 192         goto fail;
 193     }
 194     if ((chdir("/")) < 0) {
 195         goto fail;
 196     }
 197
 198     close(STDIN_FILENO);
 199     close(STDOUT_FILENO);
 200     close(STDERR_FILENO);
 201     free(pidstr);
 202     return;
 203
 204 fail:
 205     unlink(pidfile);
 206     g_critical("failed to daemonize");
 207     exit(EXIT_FAILURE);
 208 }
 209
 210 static int conn_channel_send_buf(GIOChannel *channel, const char *buf,
 211                                  gsize count)
 212 {
 213     GError *err = NULL;
 214     gsize written = 0;
 215     GIOStatus status;
 216
 217     while (count) {
 218         status = g_io_channel_write_chars(channel, buf, count, &written, &err);
 219         g_debug("sending data, count: %d", (int)count);
 220         if (err != NULL) {
 221             g_warning("error sending newline: %s", err->message);
 222             return err->code;
 223         }
 224         if (status == G_IO_STATUS_ERROR || status == G_IO_STATUS_EOF) {
 225             return -EPIPE;
 226         }
 227
 228         if (status == G_IO_STATUS_NORMAL) {
 229             count -= written;
 230         }
 231     }
 232
 233     return 0;
 234 }
 235
 236 static int conn_channel_send_payload(GIOChannel *channel, QObject *payload)
 237 {
 238     int ret = 0;
 239     const char *buf;
 240     QString *payload_qstr;
 241     GError *err = NULL;
 242
 243     g_assert(payload && channel);
 244
 245     payload_qstr = qobject_to_json(payload);
 246     if (!payload_qstr) {
 247         return -EINVAL;
 248     }
 249
 250     qstring_append_chr(payload_qstr, '\n');
 251     buf = qstring_get_str(payload_qstr);
 252     ret = conn_channel_send_buf(channel, buf, strlen(buf));
 253     if (ret) {
 254         goto out_free;
 255     }
 256
 257     g_io_channel_flush(channel, &err);
 258     if (err != NULL) {
 259         g_warning("error flushing payload: %s", err->message);
 260         ret = err->code;
 261         goto out_free;
 262     }
 263
 264 out_free:
 265     QDECREF(payload_qstr);
 266     if (err) {
 267         g_error_free(err);
 268     }
 269     return ret;
 270 }
 271
 272 static void process_command(GAState *s, QDict *req)
 273 {
 274     QObject *rsp = NULL;
 275     int ret;
 276
 277     g_assert(req);
 278     g_debug("processing command");
 279     rsp = qmp_dispatch(QOBJECT(req));
 280     if (rsp) {
 281         ret = conn_channel_send_payload(s->conn_channel, rsp);
 282         if (ret) {
 283             g_warning("error sending payload: %s", strerror(ret));
 284         }
 285         qobject_decref(rsp);
 286     } else {
 287         g_warning("error getting response");
 288     }
 289 }
 290
 291 /* handle requests/control events coming in over the channel */
 292 static void process_event(JSONMessageParser *parser, QList *tokens)
 293 {
 294     GAState *s = container_of(parser, GAState, parser);
 295     QObject *obj;
 296     QDict *qdict;
 297     Error *err = NULL;
 298     int ret;
 299
 300     g_assert(s && parser);
 301
 302     g_debug("process_event: called");
 303     obj = json_parser_parse_err(tokens, NULL, &err);
 304     if (err || !obj || qobject_type(obj) != QTYPE_QDICT) {
 305         qobject_decref(obj);
 306         qdict = qdict_new();
 307         if (!err) {
 308             g_warning("failed to parse event: unknown error");
 309             error_set(&err, QERR_JSON_PARSING);
 310         } else {
 311             g_warning("failed to parse event: %s", error_get_pretty(err));
 312         }
 313         qdict_put_obj(qdict, "error", error_get_qobject(err));
 314         error_free(err);
 315     } else {
 316         qdict = qobject_to_qdict(obj);
 317     }
 318
 319     g_assert(qdict);
 320
 321     /* handle host->guest commands */
 322     if (qdict_haskey(qdict, "execute")) {
 323         process_command(s, qdict);
 324     } else {
 325         if (!qdict_haskey(qdict, "error")) {
 326             QDECREF(qdict);
 327             qdict = qdict_new();
 328             g_warning("unrecognized payload format");
 329             error_set(&err, QERR_UNSUPPORTED);
 330             qdict_put_obj(qdict, "error", error_get_qobject(err));
 331             error_free(err);
 332         }
 333         ret = conn_channel_send_payload(s->conn_channel, QOBJECT(qdict));
 334         if (ret) {
 335             g_warning("error sending payload: %s", strerror(ret));
 336         }
 337     }
 338
 339     QDECREF(qdict);
 340 }
 341
 342 static gboolean conn_channel_read(GIOChannel *channel, GIOCondition condition,
 343                                   gpointer data)
 344 {
 345     GAState *s = data;
 346     gchar buf[1024];
 347     gsize count;
 348     GError *err = NULL;
 349     memset(buf, 0, 1024);
 350     GIOStatus status = g_io_channel_read_chars(channel, buf, 1024,
 351                                                &count, &err);
 352     if (err != NULL) {
 353         g_warning("error reading channel: %s", err->message);
 354         conn_channel_close(s);
 355         g_error_free(err);
 356         return false;
 357     }
 358     switch (status) {
 359     case G_IO_STATUS_ERROR:
 360         g_warning("problem");
 361         return false;
 362     case G_IO_STATUS_NORMAL:
 363         g_debug("read data, count: %d, data: %s", (int)count, buf);
 364         json_message_parser_feed(&s->parser, (char *)buf, (int)count);
 365     case G_IO_STATUS_AGAIN:
 366         /* virtio causes us to spin here when no process is attached to
 367          * host-side chardev. sleep a bit to mitigate this
 368          */
 369         if (s->virtio) {
 370             usleep(100*1000);
 371         }
 372         return true;
 373     case G_IO_STATUS_EOF:
 374         g_debug("received EOF");
 375         conn_channel_close(s);
 376         if (s->virtio) {
 377             return true;
 378         }
 379         return false;
 380     default:
 381         g_warning("unknown channel read status, closing");
 382         conn_channel_close(s);
 383         return false;
 384     }
 385     return true;
 386 }
 387
 388 static int conn_channel_add(GAState *s, int fd)
 389 {
 390     GIOChannel *conn_channel;
 391     GError *err = NULL;
 392
 393     g_assert(s && !s->conn_channel);
 394     conn_channel = g_io_channel_unix_new(fd);
 395     g_assert(conn_channel);
 396     g_io_channel_set_encoding(conn_channel, NULL, &err);
 397     if (err != NULL) {
 398         g_warning("error setting channel encoding to binary");
 399         g_error_free(err);
 400         return -1;
 401     }
 402     g_io_add_watch(conn_channel, G_IO_IN | G_IO_HUP,
 403                    conn_channel_read, s);
 404     s->conn_channel = conn_channel;
 405     return 0;
 406 }
 407
 408 static gboolean listen_channel_accept(GIOChannel *channel,
 409                                       GIOCondition condition, gpointer data)
 410 {
 411     GAState *s = data;
 412     g_assert(channel != NULL);
 413     int ret, conn_fd;
 414     bool accepted = false;
 415     struct sockaddr_un addr;
 416     socklen_t addrlen = sizeof(addr);
 417
 418     conn_fd = qemu_accept(g_io_channel_unix_get_fd(s->listen_channel),
 419                              (struct sockaddr *)&addr, &addrlen);
 420     if (conn_fd == -1) {
 421         g_warning("error converting fd to gsocket: %s", strerror(errno));
 422         goto out;
 423     }
 424     fcntl(conn_fd, F_SETFL, O_NONBLOCK);
 425     ret = conn_channel_add(s, conn_fd);
 426     if (ret) {
 427         g_warning("error setting up connection");
 428         goto out;
 429     }
 430     accepted = true;
 431
 432 out:
 433     /* only accept 1 connection at a time */
 434     return !accepted;
 435 }
 436
 437 /* start polling for readable events on listen fd, new==true
 438  * indicates we should use the existing s->listen_channel
 439  */
 440 static int listen_channel_add(GAState *s, int listen_fd, bool new)
 441 {
 442     if (new) {
 443         s->listen_channel = g_io_channel_unix_new(listen_fd);
 444     }
 445     g_io_add_watch(s->listen_channel, G_IO_IN,
 446                    listen_channel_accept, s);
 447     return 0;
 448 }
 449
 450 /* cleanup state for closed connection/session, start accepting new
 451  * connections if we're in listening mode
 452  */
 453 static void conn_channel_close(GAState *s)
 454 {
 455     if (strcmp(s->method, "unix-listen") == 0) {
 456         g_io_channel_shutdown(s->conn_channel, true, NULL);
 457         listen_channel_add(s, 0, false);
 458     } else if (strcmp(s->method, "virtio-serial") == 0) {
 459         /* we spin on EOF for virtio-serial, so back off a bit. also,
 460          * dont close the connection in this case, it'll resume normal
 461          * operation when another process connects to host chardev
 462          */
 463         usleep(100*1000);
 464         goto out_noclose;
 465     }
 466     g_io_channel_unref(s->conn_channel);
 467     s->conn_channel = NULL;
 468 out_noclose:
 469     return;
 470 }
 471
 472 static void init_guest_agent(GAState *s)
 473 {
 474     struct termios tio;
 475     int ret, fd;
 476
 477     if (s->method == NULL) {
 478         /* try virtio-serial as our default */
 479         s->method = "virtio-serial";
 480     }
 481
 482     if (s->path == NULL) {
 483         if (strcmp(s->method, "virtio-serial") != 0) {
 484             g_critical("must specify a path for this channel");
 485             exit(EXIT_FAILURE);
 486         }
 487         /* try the default path for the virtio-serial port */
 488         s->path = QGA_VIRTIO_PATH_DEFAULT;
 489     }
 490
 491     if (strcmp(s->method, "virtio-serial") == 0) {
 492         s->virtio = true;
 493         fd = qemu_open(s->path, O_RDWR | O_NONBLOCK | O_ASYNC);
 494         if (fd == -1) {
 495             g_critical("error opening channel: %s", strerror(errno));
 496             exit(EXIT_FAILURE);
 497         }
 498         ret = conn_channel_add(s, fd);
 499         if (ret) {
 500             g_critical("error adding channel to main loop");
 501             exit(EXIT_FAILURE);
 502         }
 503     } else if (strcmp(s->method, "isa-serial") == 0) {
 504         fd = qemu_open(s->path, O_RDWR | O_NOCTTY);
 505         if (fd == -1) {
 506             g_critical("error opening channel: %s", strerror(errno));
 507             exit(EXIT_FAILURE);
 508         }
 509         tcgetattr(fd, &tio);
 510         /* set up serial port for non-canonical, dumb byte streaming */
 511         tio.c_iflag &= ~(IGNBRK | BRKINT | IGNPAR | PARMRK | INPCK | ISTRIP |
 512                          INLCR | IGNCR | ICRNL | IXON | IXOFF | IXANY |
 513                          IMAXBEL);
 514         tio.c_oflag = 0;
 515         tio.c_lflag = 0;
 516         tio.c_cflag |= QGA_BAUDRATE_DEFAULT;
 517         /* 1 available byte min or reads will block (we'll set non-blocking
 518          * elsewhere, else we have to deal with read()=0 instead)
 519          */
 520         tio.c_cc[VMIN] = 1;
 521         tio.c_cc[VTIME] = 0;
 522         /* flush everything waiting for read/xmit, it's garbage at this point */
 523         tcflush(fd, TCIFLUSH);
 524         tcsetattr(fd, TCSANOW, &tio);
 525         ret = conn_channel_add(s, fd);
 526         if (ret) {
 527             g_error("error adding channel to main loop");
 528         }
 529     } else if (strcmp(s->method, "unix-listen") == 0) {
 530         fd = unix_listen(s->path, NULL, strlen(s->path));
 531         if (fd == -1) {
 532             g_critical("error opening path: %s", strerror(errno));
 533             exit(EXIT_FAILURE);
 534         }
 535         ret = listen_channel_add(s, fd, true);
 536         if (ret) {
 537             g_critical("error binding/listening to specified socket");
 538             exit(EXIT_FAILURE);
 539         }
 540     } else {
 541         g_critical("unsupported channel method/type: %s", s->method);
 542         exit(EXIT_FAILURE);
 543     }
 544
 545     json_message_parser_init(&s->parser, process_event);
 546     s->main_loop = g_main_loop_new(NULL, false);
 547 }
 548
 549 int main(int argc, char **argv)
 550 {
 551     const char *sopt = "hVvdm:p:l:f:";
 552     const char *method = NULL, *path = NULL, *pidfile = QGA_PIDFILE_DEFAULT;
 553     const struct option lopt[] = {
 554         { "help", 0, NULL, 'h' },
 555         { "version", 0, NULL, 'V' },
 556         { "logfile", 0, NULL, 'l' },
 557         { "pidfile", 0, NULL, 'f' },
 558         { "verbose", 0, NULL, 'v' },
 559         { "method", 0, NULL, 'm' },
 560         { "path", 0, NULL, 'p' },
 561         { "daemonize", 0, NULL, 'd' },
 562         { NULL, 0, NULL, 0 }
 563     };
 564     int opt_ind = 0, ch, daemonize = 0;
 565     GLogLevelFlags log_level = G_LOG_LEVEL_ERROR | G_LOG_LEVEL_CRITICAL;
 566     FILE *log_file = stderr;
 567     GAState *s;
 568
 569     while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
 570         switch (ch) {
 571         case 'm':
 572             method = optarg;
 573             break;
 574         case 'p':
 575             path = optarg;
 576             break;
 577         case 'l':
 578             log_file = fopen(optarg, "a");
 579             if (!log_file) {
 580                 g_critical("unable to open specified log file: %s",
 581                            strerror(errno));
 582                 return EXIT_FAILURE;
 583             }
 584             break;
 585         case 'f':
 586             pidfile = optarg;
 587             break;
 588         case 'v':
 589             /* enable all log levels */
 590             log_level = G_LOG_LEVEL_MASK;
 591             break;
 592         case 'V':
 593             printf("QEMU Guest Agent %s\n", QGA_VERSION);
 594             return 0;
 595         case 'd':
 596             daemonize = 1;
 597             break;
 598         case 'h':
 599             usage(argv[0]);
 600             return 0;
 601         case '?':
 602             g_print("Unknown option, try '%s --help' for more information.\n",
 603                     argv[0]);
 604             return EXIT_FAILURE;
 605         }
 606     }
 607
 608     if (daemonize) {
 609         g_debug("starting daemon");
 610         become_daemon(pidfile);
 611     }
 612
 613     s = g_malloc0(sizeof(GAState));
 614     s->conn_channel = NULL;
 615     s->path = path;
 616     s->method = method;
 617     s->log_file = log_file;
 618     s->log_level = log_level;
 619     g_log_set_default_handler(ga_log, s);
 620     g_log_set_fatal_mask(NULL, G_LOG_LEVEL_ERROR);
 621     s->logging_enabled = true;
 622     s->command_state = ga_command_state_new();
 623     ga_command_state_init(s, s->command_state);
 624     ga_command_state_init_all(s->command_state);
 625     ga_state = s;
 626
 627     module_call_init(MODULE_INIT_QAPI);
 628     init_guest_agent(ga_state);
 629     register_signal_handlers();
 630
 631     g_main_loop_run(ga_state->main_loop);
 632
 633     ga_command_state_cleanup_all(ga_state->command_state);
 634     unlink(pidfile);
 635
 636     return 0;
 637 }