qga/main.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
  14 #include "qemu/osdep.h"
  15 #include <getopt.h>
  16 #include <glib/gstdio.h>
  17 #ifndef _WIN32
  18 #include <syslog.h>
  19 #include <sys/wait.h>
  20 #endif
  21 #include "qemu/help-texts.h"
  22 #include "qapi/qmp/json-parser.h"
  23 #include "qapi/qmp/qdict.h"
  24 #include "qapi/qmp/qjson.h"
  25 #include "guest-agent-core.h"
  26 #include "qga-qapi-init-commands.h"
  27 #include "qapi/error.h"
  28 #include "channel.h"
  29 #include "qemu/cutils.h"
  30 #include "qemu/help_option.h"
  31 #include "qemu/sockets.h"
  32 #include "qemu/systemd.h"
  33 #include "qemu-version.h"
  34 #ifdef _WIN32
  35 #include <dbt.h>
  36 #include "qga/service-win32.h"
  37 #include "qga/vss-win32.h"
  38 #endif
  39 #include "commands-common.h"
  40
  41 #ifndef _WIN32
  42 #ifdef CONFIG_BSD
  43 #define QGA_VIRTIO_PATH_DEFAULT "/dev/vtcon/org.qemu.guest_agent.0"
  44 #else /* CONFIG_BSD */
  45 #define QGA_VIRTIO_PATH_DEFAULT "/dev/virtio-ports/org.qemu.guest_agent.0"
  46 #endif /* CONFIG_BSD */
  47 #define QGA_SERIAL_PATH_DEFAULT "/dev/ttyS0"
  48 #define QGA_STATE_RELATIVE_DIR  "run"
  49 #else
  50 #define QGA_VIRTIO_PATH_DEFAULT "\\\\.\\Global\\org.qemu.guest_agent.0"
  51 #define QGA_STATE_RELATIVE_DIR  "qemu-ga"
  52 #define QGA_SERIAL_PATH_DEFAULT "COM1"
  53 #endif
  54 #ifdef CONFIG_FSFREEZE
  55 #define QGA_FSFREEZE_HOOK_DEFAULT CONFIG_QEMU_CONFDIR "/fsfreeze-hook"
  56 #endif
  57 #define QGA_SENTINEL_BYTE 0xFF
  58 #define QGA_CONF_DEFAULT CONFIG_QEMU_CONFDIR G_DIR_SEPARATOR_S "qemu-ga.conf"
  59 #define QGA_RETRY_INTERVAL 5
  60
  61 static struct {
  62     const char *state_dir;
  63     const char *pidfile;
  64 } dfl_pathnames;
  65
  66 typedef struct GAPersistentState {
  67 #define QGA_PSTATE_DEFAULT_FD_COUNTER 1000
  68     int64_t fd_counter;
  69 } GAPersistentState;
  70
  71 typedef struct GAConfig GAConfig;
  72
  73 struct GAState {
  74     JSONMessageParser parser;
  75     GMainLoop *main_loop;
  76     GAChannel *channel;
  77     bool virtio; /* fastpath to check for virtio to deal with poll() quirks */
  78     GACommandState *command_state;
  79     GLogLevelFlags log_level;
  80     FILE *log_file;
  81     bool logging_enabled;
  82 #ifdef _WIN32
  83     GAService service;
  84     HANDLE wakeup_event;
  85     HANDLE event_log;
  86 #endif
  87     bool delimit_response;
  88     bool frozen;
  89     GList *blockedrpcs;
  90     GList *allowedrpcs;
  91     char *state_filepath_isfrozen;
  92     struct {
  93         const char *log_filepath;
  94         const char *pid_filepath;
  95     } deferred_options;
  96 #ifdef CONFIG_FSFREEZE
  97     const char *fsfreeze_hook;
  98 #endif
  99     gchar *pstate_filepath;
 100     GAPersistentState pstate;
 101     GAConfig *config;
 102     int socket_activation;
 103     bool force_exit;
 104 };
 105
 106 struct GAState *ga_state;
 107 QmpCommandList ga_commands;
 108
 109 /* commands that are safe to issue while filesystems are frozen */
 110 static const char *ga_freeze_allowlist[] = {
 111     "guest-ping",
 112     "guest-info",
 113     "guest-sync",
 114     "guest-sync-delimited",
 115     "guest-fsfreeze-status",
 116     "guest-fsfreeze-thaw",
 117     NULL
 118 };
 119
 120 #ifdef _WIN32
 121 DWORD WINAPI service_ctrl_handler(DWORD ctrl, DWORD type, LPVOID data,
 122                                   LPVOID ctx);
 123 DWORD WINAPI handle_serial_device_events(DWORD type, LPVOID data);
 124 VOID WINAPI service_main(DWORD argc, TCHAR *argv[]);
 125 #endif
 126 static int run_agent(GAState *s);
 127 static void stop_agent(GAState *s, bool requested);
 128
 129 static void
 130 init_dfl_pathnames(void)
 131 {
 132     g_autofree char *state = qemu_get_local_state_dir();
 133
 134     g_assert(dfl_pathnames.state_dir == NULL);
 135     g_assert(dfl_pathnames.pidfile == NULL);
 136     dfl_pathnames.state_dir = g_build_filename(state, QGA_STATE_RELATIVE_DIR, NULL);
 137     dfl_pathnames.pidfile = g_build_filename(state, QGA_STATE_RELATIVE_DIR, "qemu-ga.pid", NULL);
 138 }
 139
 140 static void quit_handler(int sig)
 141 {
 142     /* if we're frozen, don't exit unless we're absolutely forced to,
 143      * because it's basically impossible for graceful exit to complete
 144      * unless all log/pid files are on unfreezable filesystems. there's
 145      * also a very likely chance killing the agent before unfreezing
 146      * the filesystems is a mistake (or will be viewed as one later).
 147      * On Windows the freeze interval is limited to 10 seconds, so
 148      * we should quit, but first we should wait for the timeout, thaw
 149      * the filesystem and quit.
 150      */
 151     if (ga_is_frozen(ga_state)) {
 152 #ifdef _WIN32
 153         int i = 0;
 154         Error *err = NULL;
 155         HANDLE hEventTimeout;
 156
 157         g_debug("Thawing filesystems before exiting");
 158
 159         hEventTimeout = OpenEvent(EVENT_ALL_ACCESS, FALSE, EVENT_NAME_TIMEOUT);
 160         if (hEventTimeout) {
 161             WaitForSingleObject(hEventTimeout, 0);
 162             CloseHandle(hEventTimeout);
 163         }
 164         qga_vss_fsfreeze(&i, false, NULL, &err);
 165         if (err) {
 166             g_debug("Error unfreezing filesystems prior to exiting: %s",
 167                 error_get_pretty(err));
 168             error_free(err);
 169         }
 170 #else
 171         return;
 172 #endif
 173     }
 174     g_debug("received signal num %d, quitting", sig);
 175
 176     stop_agent(ga_state, true);
 177 }
 178
 179 #ifndef _WIN32
 180 static gboolean register_signal_handlers(void)
 181 {
 182     struct sigaction sigact;
 183     int ret;
 184
 185     memset(&sigact, 0, sizeof(struct sigaction));
 186     sigact.sa_handler = quit_handler;
 187
 188     ret = sigaction(SIGINT, &sigact, NULL);
 189     if (ret == -1) {
 190         g_error("error configuring signal handler: %s", strerror(errno));
 191     }
 192     ret = sigaction(SIGTERM, &sigact, NULL);
 193     if (ret == -1) {
 194         g_error("error configuring signal handler: %s", strerror(errno));
 195     }
 196
 197     sigact.sa_handler = SIG_IGN;
 198     if (sigaction(SIGPIPE, &sigact, NULL) != 0) {
 199         g_error("error configuring SIGPIPE signal handler: %s",
 200                 strerror(errno));
 201     }
 202
 203     return true;
 204 }
 205
 206 /* TODO: use this in place of all post-fork() fclose(std*) callers */
 207 void reopen_fd_to_null(int fd)
 208 {
 209     int nullfd;
 210
 211     nullfd = open("/dev/null", O_RDWR);
 212     if (nullfd < 0) {
 213         return;
 214     }
 215
 216     dup2(nullfd, fd);
 217
 218     if (nullfd != fd) {
 219         close(nullfd);
 220     }
 221 }
 222 #endif
 223
 224 static void usage(const char *cmd)
 225 {
 226 #ifdef CONFIG_FSFREEZE
 227     g_autofree char *fsfreeze_hook = get_relocated_path(QGA_FSFREEZE_HOOK_DEFAULT);
 228 #endif
 229
 230     printf(
 231 "Usage: %s [-m <method> -p <path>] [<options>]\n"
 232 "QEMU Guest Agent " QEMU_FULL_VERSION "\n"
 233 QEMU_COPYRIGHT "\n"
 234 "\n"
 235 "  -m, --method      transport method: one of unix-listen, virtio-serial,\n"
 236 "                    isa-serial, or vsock-listen (virtio-serial is the default)\n"
 237 "  -p, --path        device/socket path (the default for virtio-serial is:\n"
 238 "                    %s,\n"
 239 "                    the default for isa-serial is:\n"
 240 "                    %s).\n"
 241 "                    Socket addresses for vsock-listen are written as\n"
 242 "                    <cid>:<port>.\n"
 243 "  -l, --logfile     set logfile path, logs to stderr by default\n"
 244 "  -f, --pidfile     specify pidfile (default is %s)\n"
 245 #ifdef CONFIG_FSFREEZE
 246 "  -F, --fsfreeze-hook\n"
 247 "                    enable fsfreeze hook. Accepts an optional argument that\n"
 248 "                    specifies script to run on freeze/thaw. Script will be\n"
 249 "                    called with 'freeze'/'thaw' arguments accordingly.\n"
 250 "                    (default is %s)\n"
 251 "                    If using -F with an argument, do not follow -F with a\n"
 252 "                    space.\n"
 253 "                    (for example: -F/var/run/fsfreezehook.sh)\n"
 254 #endif
 255 "  -t, --statedir    specify dir to store state information (absolute paths\n"
 256 "                    only, default is %s)\n"
 257 "  -v, --verbose     log extra debugging information\n"
 258 "  -V, --version     print version information and exit\n"
 259 "  -d, --daemonize   become a daemon\n"
 260 #ifdef _WIN32
 261 "  -s, --service     service commands: install, uninstall, vss-install, vss-uninstall\n"
 262 #endif
 263 "  -b, --block-rpcs  comma-separated list of RPCs to disable (no spaces,\n"
 264 "                    use \"--block-rpcs=help\" to list available RPCs)\n"
 265 "  -a, --allow-rpcs  comma-separated list of RPCs to enable (no spaces,\n"
 266 "                    use \"--allow-rpcs=help\" to list available RPCs)\n"
 267 "  -D, --dump-conf   dump a qemu-ga config file based on current config\n"
 268 "                    options / command-line parameters to stdout\n"
 269 "  -r, --retry-path  attempt re-opening path if it's unavailable or closed\n"
 270 "                    due to an error which may be recoverable in the future\n"
 271 "                    (virtio-serial driver re-install, serial device hot\n"
 272 "                    plug/unplug, etc.)\n"
 273 "  -h, --help        display this help and exit\n"
 274 "\n"
 275 QEMU_HELP_BOTTOM "\n"
 276     , cmd, QGA_VIRTIO_PATH_DEFAULT, QGA_SERIAL_PATH_DEFAULT,
 277     dfl_pathnames.pidfile,
 278 #ifdef CONFIG_FSFREEZE
 279     fsfreeze_hook,
 280 #endif
 281     dfl_pathnames.state_dir);
 282 }
 283
 284 static const char *ga_log_level_str(GLogLevelFlags level)
 285 {
 286     switch (level & G_LOG_LEVEL_MASK) {
 287     case G_LOG_LEVEL_ERROR:
 288         return "error";
 289     case G_LOG_LEVEL_CRITICAL:
 290         return "critical";
 291     case G_LOG_LEVEL_WARNING:
 292         return "warning";
 293     case G_LOG_LEVEL_MESSAGE:
 294         return "message";
 295     case G_LOG_LEVEL_INFO:
 296         return "info";
 297     case G_LOG_LEVEL_DEBUG:
 298         return "debug";
 299     default:
 300         return "user";
 301     }
 302 }
 303
 304 bool ga_logging_enabled(GAState *s)
 305 {
 306     return s->logging_enabled;
 307 }
 308
 309 void ga_disable_logging(GAState *s)
 310 {
 311     s->logging_enabled = false;
 312 }
 313
 314 void ga_enable_logging(GAState *s)
 315 {
 316     s->logging_enabled = true;
 317 }
 318
 319 static int glib_log_level_to_system(int level)
 320 {
 321     switch (level) {
 322 #ifndef _WIN32
 323     case G_LOG_LEVEL_ERROR:
 324         return LOG_ERR;
 325     case G_LOG_LEVEL_CRITICAL:
 326         return LOG_CRIT;
 327     case G_LOG_LEVEL_WARNING:
 328         return LOG_WARNING;
 329     case G_LOG_LEVEL_MESSAGE:
 330         return LOG_NOTICE;
 331     case G_LOG_LEVEL_DEBUG:
 332         return LOG_DEBUG;
 333     case G_LOG_LEVEL_INFO:
 334     default:
 335         return LOG_INFO;
 336 #else
 337     case G_LOG_LEVEL_ERROR:
 338     case G_LOG_LEVEL_CRITICAL:
 339         return EVENTLOG_ERROR_TYPE;
 340     case G_LOG_LEVEL_WARNING:
 341         return EVENTLOG_WARNING_TYPE;
 342     case G_LOG_LEVEL_MESSAGE:
 343     case G_LOG_LEVEL_INFO:
 344     case G_LOG_LEVEL_DEBUG:
 345     default:
 346         return EVENTLOG_INFORMATION_TYPE;
 347 #endif
 348     }
 349 }
 350
 351 static void ga_log(const gchar *domain, GLogLevelFlags level,
 352                    const gchar *msg, gpointer opaque)
 353 {
 354     GAState *s = opaque;
 355     const char *level_str = ga_log_level_str(level);
 356
 357     if (!ga_logging_enabled(s)) {
 358         return;
 359     }
 360
 361     level &= G_LOG_LEVEL_MASK;
 362     if (g_strcmp0(domain, "syslog") == 0) {
 363 #ifndef _WIN32
 364         syslog(glib_log_level_to_system(level), "%s: %s", level_str, msg);
 365 #else
 366         ReportEvent(s->event_log, glib_log_level_to_system(level),
 367                     0, 1, NULL, 1, 0, &msg, NULL);
 368 #endif
 369     } else if (level & s->log_level) {
 370         g_autoptr(GDateTime) now = g_date_time_new_now_utc();
 371         g_autofree char *nowstr = g_date_time_format(now, "%s.%f");
 372         fprintf(s->log_file, "%s: %s: %s\n", nowstr, level_str, msg);
 373         fflush(s->log_file);
 374     }
 375 }
 376
 377 void ga_set_response_delimited(GAState *s)
 378 {
 379     s->delimit_response = true;
 380 }
 381
 382 static FILE *ga_open_logfile(const char *logfile)
 383 {
 384     FILE *f;
 385
 386     f = fopen(logfile, "a");
 387     if (!f) {
 388         return NULL;
 389     }
 390
 391     qemu_set_cloexec(fileno(f));
 392     return f;
 393 }
 394
 395 static gint ga_strcmp(gconstpointer str1, gconstpointer str2)
 396 {
 397     return strcmp(str1, str2);
 398 }
 399
 400 /* disable commands that aren't safe for fsfreeze */
 401 static void ga_disable_not_allowed_freeze(const QmpCommand *cmd, void *opaque)
 402 {
 403     bool allowed = false;
 404     int i = 0;
 405     const char *name = qmp_command_name(cmd);
 406
 407     while (ga_freeze_allowlist[i] != NULL) {
 408         if (strcmp(name, ga_freeze_allowlist[i]) == 0) {
 409             allowed = true;
 410         }
 411         i++;
 412     }
 413     if (!allowed) {
 414         g_debug("disabling command: %s", name);
 415         qmp_disable_command(&ga_commands, name, "the agent is in frozen state");
 416     }
 417 }
 418
 419 /* [re-]enable all commands, except those explicitly blocked by user */
 420 static void ga_enable_non_blocked(const QmpCommand *cmd, void *opaque)
 421 {
 422     GAState *s = opaque;
 423     GList *blockedrpcs = s->blockedrpcs;
 424     GList *allowedrpcs = s->allowedrpcs;
 425     const char *name = qmp_command_name(cmd);
 426
 427     if (g_list_find_custom(blockedrpcs, name, ga_strcmp) == NULL) {
 428         if (qmp_command_is_enabled(cmd)) {
 429             return;
 430         }
 431
 432         if (allowedrpcs &&
 433             g_list_find_custom(allowedrpcs, name, ga_strcmp) == NULL) {
 434             return;
 435         }
 436
 437         g_debug("enabling command: %s", name);
 438         qmp_enable_command(&ga_commands, name);
 439     }
 440 }
 441
 442 /* disable commands that aren't allowed */
 443 static void ga_disable_not_allowed(const QmpCommand *cmd, void *opaque)
 444 {
 445     GList *allowedrpcs = opaque;
 446     const char *name = qmp_command_name(cmd);
 447
 448     if (g_list_find_custom(allowedrpcs, name, ga_strcmp) == NULL) {
 449         g_debug("disabling command: %s", name);
 450         qmp_disable_command(&ga_commands, name, "the command is not allowed");
 451     }
 452 }
 453
 454 static bool ga_create_file(const char *path)
 455 {
 456     int fd = open(path, O_CREAT | O_WRONLY, S_IWUSR | S_IRUSR);
 457     if (fd == -1) {
 458         g_warning("unable to open/create file %s: %s", path, strerror(errno));
 459         return false;
 460     }
 461     close(fd);
 462     return true;
 463 }
 464
 465 static bool ga_delete_file(const char *path)
 466 {
 467     int ret = unlink(path);
 468     if (ret == -1) {
 469         g_warning("unable to delete file: %s: %s", path, strerror(errno));
 470         return false;
 471     }
 472
 473     return true;
 474 }
 475
 476 bool ga_is_frozen(GAState *s)
 477 {
 478     return s->frozen;
 479 }
 480
 481 void ga_set_frozen(GAState *s)
 482 {
 483     if (ga_is_frozen(s)) {
 484         return;
 485     }
 486     /* disable all forbidden (for frozen state) commands */
 487     qmp_for_each_command(&ga_commands, ga_disable_not_allowed_freeze, NULL);
 488     g_warning("disabling logging due to filesystem freeze");
 489     ga_disable_logging(s);
 490     s->frozen = true;
 491     if (!ga_create_file(s->state_filepath_isfrozen)) {
 492         g_warning("unable to create %s, fsfreeze may not function properly",
 493                   s->state_filepath_isfrozen);
 494     }
 495 }
 496
 497 void ga_unset_frozen(GAState *s)
 498 {
 499     if (!ga_is_frozen(s)) {
 500         return;
 501     }
 502
 503     /* if we delayed creation/opening of pid/log files due to being
 504      * in a frozen state at start up, do it now
 505      */
 506     if (s->deferred_options.log_filepath) {
 507         s->log_file = ga_open_logfile(s->deferred_options.log_filepath);
 508         if (!s->log_file) {
 509             s->log_file = stderr;
 510         }
 511         s->deferred_options.log_filepath = NULL;
 512     }
 513     ga_enable_logging(s);
 514     g_warning("logging re-enabled due to filesystem unfreeze");
 515     if (s->deferred_options.pid_filepath) {
 516         Error *err = NULL;
 517
 518         if (!qemu_write_pidfile(s->deferred_options.pid_filepath, &err)) {
 519             g_warning("%s", error_get_pretty(err));
 520             error_free(err);
 521         }
 522         s->deferred_options.pid_filepath = NULL;
 523     }
 524
 525     /* enable all disabled, non-blocked and allowed commands */
 526     qmp_for_each_command(&ga_commands, ga_enable_non_blocked, s);
 527     s->frozen = false;
 528     if (!ga_delete_file(s->state_filepath_isfrozen)) {
 529         g_warning("unable to delete %s, fsfreeze may not function properly",
 530                   s->state_filepath_isfrozen);
 531     }
 532 }
 533
 534 #ifdef CONFIG_FSFREEZE
 535 const char *ga_fsfreeze_hook(GAState *s)
 536 {
 537     return s->fsfreeze_hook;
 538 }
 539 #endif
 540
 541 static void become_daemon(const char *pidfile)
 542 {
 543 #ifndef _WIN32
 544     pid_t pid, sid;
 545
 546     pid = fork();
 547     if (pid < 0) {
 548         exit(EXIT_FAILURE);
 549     }
 550     if (pid > 0) {
 551         exit(EXIT_SUCCESS);
 552     }
 553
 554     if (pidfile) {
 555         Error *err = NULL;
 556
 557         if (!qemu_write_pidfile(pidfile, &err)) {
 558             g_critical("%s", error_get_pretty(err));
 559             error_free(err);
 560             exit(EXIT_FAILURE);
 561         }
 562     }
 563
 564     umask(S_IRWXG | S_IRWXO);
 565     sid = setsid();
 566     if (sid < 0) {
 567         goto fail;
 568     }
 569     if ((chdir("/")) < 0) {
 570         goto fail;
 571     }
 572
 573     reopen_fd_to_null(STDIN_FILENO);
 574     reopen_fd_to_null(STDOUT_FILENO);
 575     reopen_fd_to_null(STDERR_FILENO);
 576     return;
 577
 578 fail:
 579     if (pidfile) {
 580         unlink(pidfile);
 581     }
 582     g_critical("failed to daemonize");
 583     exit(EXIT_FAILURE);
 584 #endif
 585 }
 586
 587 static int send_response(GAState *s, const QDict *rsp)
 588 {
 589     GString *response;
 590     GIOStatus status;
 591
 592     g_assert(s->channel);
 593
 594     if (!rsp) {
 595         return 0;
 596     }
 597
 598     response = qobject_to_json(QOBJECT(rsp));
 599     if (!response) {
 600         return -EINVAL;
 601     }
 602
 603     if (s->delimit_response) {
 604         s->delimit_response = false;
 605         g_string_prepend_c(response, QGA_SENTINEL_BYTE);
 606     }
 607
 608     g_string_append_c(response, '\n');
 609     status = ga_channel_write_all(s->channel, response->str, response->len);
 610     g_string_free(response, true);
 611     if (status != G_IO_STATUS_NORMAL) {
 612         return -EIO;
 613     }
 614
 615     return 0;
 616 }
 617
 618 /* handle requests/control events coming in over the channel */
 619 static void process_event(void *opaque, QObject *obj, Error *err)
 620 {
 621     GAState *s = opaque;
 622     QDict *rsp;
 623     int ret;
 624
 625     g_debug("process_event: called");
 626     assert(!obj != !err);
 627     if (err) {
 628         rsp = qmp_error_response(err);
 629         goto end;
 630     }
 631
 632     g_debug("processing command");
 633     rsp = qmp_dispatch(&ga_commands, obj, false, NULL);
 634
 635 end:
 636     ret = send_response(s, rsp);
 637     if (ret < 0) {
 638         g_warning("error sending error response: %s", strerror(-ret));
 639     }
 640     qobject_unref(rsp);
 641     qobject_unref(obj);
 642 }
 643
 644 /* false return signals GAChannel to close the current client connection */
 645 static gboolean channel_event_cb(GIOCondition condition, gpointer data)
 646 {
 647     GAState *s = data;
 648     gchar buf[QGA_READ_COUNT_DEFAULT + 1];
 649     gsize count;
 650     GIOStatus status = ga_channel_read(s->channel, buf, QGA_READ_COUNT_DEFAULT, &count);
 651     switch (status) {
 652     case G_IO_STATUS_ERROR:
 653         g_warning("error reading channel");
 654         stop_agent(s, false);
 655         return false;
 656     case G_IO_STATUS_NORMAL:
 657         buf[count] = 0;
 658         g_debug("read data, count: %d, data: %s", (int)count, buf);
 659         json_message_parser_feed(&s->parser, (char *)buf, (int)count);
 660         break;
 661     case G_IO_STATUS_EOF:
 662         g_debug("received EOF");
 663         if (!s->virtio) {
 664             return false;
 665         }
 666         /* fall through */
 667     case G_IO_STATUS_AGAIN:
 668         /* virtio causes us to spin here when no process is attached to
 669          * host-side chardev. sleep a bit to mitigate this
 670          */
 671         if (s->virtio) {
 672             g_usleep(G_USEC_PER_SEC / 10);
 673         }
 674         return true;
 675     default:
 676         g_warning("unknown channel read status, closing");
 677         return false;
 678     }
 679     return true;
 680 }
 681
 682 static gboolean channel_init(GAState *s, const gchar *method, const gchar *path,
 683                              int listen_fd)
 684 {
 685     GAChannelMethod channel_method;
 686
 687     if (strcmp(method, "virtio-serial") == 0) {
 688         s->virtio = true; /* virtio requires special handling in some cases */
 689         channel_method = GA_CHANNEL_VIRTIO_SERIAL;
 690     } else if (strcmp(method, "isa-serial") == 0) {
 691         channel_method = GA_CHANNEL_ISA_SERIAL;
 692     } else if (strcmp(method, "unix-listen") == 0) {
 693         channel_method = GA_CHANNEL_UNIX_LISTEN;
 694     } else if (strcmp(method, "vsock-listen") == 0) {
 695         channel_method = GA_CHANNEL_VSOCK_LISTEN;
 696     } else {
 697         g_critical("unsupported channel method/type: %s", method);
 698         return false;
 699     }
 700
 701     s->channel = ga_channel_new(channel_method, path, listen_fd,
 702                                 channel_event_cb, s);
 703     if (!s->channel) {
 704         g_critical("failed to create guest agent channel");
 705         return false;
 706     }
 707
 708     return true;
 709 }
 710
 711 #ifdef _WIN32
 712 DWORD WINAPI handle_serial_device_events(DWORD type, LPVOID data)
 713 {
 714     DWORD ret = NO_ERROR;
 715     PDEV_BROADCAST_HDR broadcast_header = (PDEV_BROADCAST_HDR)data;
 716
 717     if (broadcast_header->dbch_devicetype == DBT_DEVTYP_DEVICEINTERFACE) {
 718         switch (type) {
 719             /* Device inserted */
 720         case DBT_DEVICEARRIVAL:
 721             /* Start QEMU-ga's service */
 722             if (!SetEvent(ga_state->wakeup_event)) {
 723                 ret = GetLastError();
 724             }
 725             break;
 726             /* Device removed */
 727         case DBT_DEVICEQUERYREMOVE:
 728         case DBT_DEVICEREMOVEPENDING:
 729         case DBT_DEVICEREMOVECOMPLETE:
 730             /* Stop QEMU-ga's service */
 731             if (!ResetEvent(ga_state->wakeup_event)) {
 732                 ret = GetLastError();
 733             }
 734             break;
 735         default:
 736             ret = ERROR_CALL_NOT_IMPLEMENTED;
 737         }
 738     }
 739     return ret;
 740 }
 741
 742 DWORD WINAPI service_ctrl_handler(DWORD ctrl, DWORD type, LPVOID data,
 743                                   LPVOID ctx)
 744 {
 745     DWORD ret = NO_ERROR;
 746     GAService *service = &ga_state->service;
 747
 748     switch (ctrl) {
 749     case SERVICE_CONTROL_STOP:
 750     case SERVICE_CONTROL_SHUTDOWN:
 751         quit_handler(SIGTERM);
 752         SetEvent(ga_state->wakeup_event);
 753         service->status.dwCurrentState = SERVICE_STOP_PENDING;
 754         SetServiceStatus(service->status_handle, &service->status);
 755         break;
 756     case SERVICE_CONTROL_DEVICEEVENT:
 757         handle_serial_device_events(type, data);
 758         break;
 759
 760     default:
 761         ret = ERROR_CALL_NOT_IMPLEMENTED;
 762     }
 763     return ret;
 764 }
 765
 766 VOID WINAPI service_main(DWORD argc, TCHAR *argv[])
 767 {
 768     GAService *service = &ga_state->service;
 769
 770     service->status_handle = RegisterServiceCtrlHandlerEx(QGA_SERVICE_NAME,
 771         service_ctrl_handler, NULL);
 772
 773     if (service->status_handle == 0) {
 774         g_critical("Failed to register extended requests function!\n");
 775         return;
 776     }
 777
 778     service->status.dwServiceType = SERVICE_WIN32;
 779     service->status.dwCurrentState = SERVICE_RUNNING;
 780     service->status.dwControlsAccepted = SERVICE_ACCEPT_STOP | SERVICE_ACCEPT_SHUTDOWN;
 781     service->status.dwWin32ExitCode = NO_ERROR;
 782     service->status.dwServiceSpecificExitCode = NO_ERROR;
 783     service->status.dwCheckPoint = 0;
 784     service->status.dwWaitHint = 0;
 785     DEV_BROADCAST_DEVICEINTERFACE notification_filter;
 786     ZeroMemory(&notification_filter, sizeof(notification_filter));
 787     notification_filter.dbcc_devicetype = DBT_DEVTYP_DEVICEINTERFACE;
 788     notification_filter.dbcc_size = sizeof(DEV_BROADCAST_DEVICEINTERFACE);
 789     notification_filter.dbcc_classguid = GUID_VIOSERIAL_PORT;
 790
 791     service->device_notification_handle =
 792         RegisterDeviceNotification(service->status_handle,
 793             &notification_filter, DEVICE_NOTIFY_SERVICE_HANDLE);
 794     if (!service->device_notification_handle) {
 795         g_critical("Failed to register device notification handle!\n");
 796         return;
 797     }
 798     SetServiceStatus(service->status_handle, &service->status);
 799
 800     run_agent(ga_state);
 801
 802     UnregisterDeviceNotification(service->device_notification_handle);
 803     service->status.dwCurrentState = SERVICE_STOPPED;
 804     SetServiceStatus(service->status_handle, &service->status);
 805 }
 806 #endif
 807
 808 static void set_persistent_state_defaults(GAPersistentState *pstate)
 809 {
 810     g_assert(pstate);
 811     pstate->fd_counter = QGA_PSTATE_DEFAULT_FD_COUNTER;
 812 }
 813
 814 static void persistent_state_from_keyfile(GAPersistentState *pstate,
 815                                           GKeyFile *keyfile)
 816 {
 817     g_assert(pstate);
 818     g_assert(keyfile);
 819     /* if any fields are missing, either because the file was tampered with
 820      * by agents of chaos, or because the field wasn't present at the time the
 821      * file was created, the best we can ever do is start over with the default
 822      * values. so load them now, and ignore any errors in accessing key-value
 823      * pairs
 824      */
 825     set_persistent_state_defaults(pstate);
 826
 827     if (g_key_file_has_key(keyfile, "global", "fd_counter", NULL)) {
 828         pstate->fd_counter =
 829             g_key_file_get_integer(keyfile, "global", "fd_counter", NULL);
 830     }
 831 }
 832
 833 static void persistent_state_to_keyfile(const GAPersistentState *pstate,
 834                                         GKeyFile *keyfile)
 835 {
 836     g_assert(pstate);
 837     g_assert(keyfile);
 838
 839     g_key_file_set_integer(keyfile, "global", "fd_counter", pstate->fd_counter);
 840 }
 841
 842 static gboolean write_persistent_state(const GAPersistentState *pstate,
 843                                        const gchar *path)
 844 {
 845     GKeyFile *keyfile = g_key_file_new();
 846     GError *gerr = NULL;
 847     gboolean ret = true;
 848     gchar *data = NULL;
 849     gsize data_len;
 850
 851     g_assert(pstate);
 852
 853     persistent_state_to_keyfile(pstate, keyfile);
 854     data = g_key_file_to_data(keyfile, &data_len, &gerr);
 855     if (gerr) {
 856         g_critical("failed to convert persistent state to string: %s",
 857                    gerr->message);
 858         ret = false;
 859         goto out;
 860     }
 861
 862     g_file_set_contents(path, data, data_len, &gerr);
 863     if (gerr) {
 864         g_critical("failed to write persistent state to %s: %s",
 865                     path, gerr->message);
 866         ret = false;
 867         goto out;
 868     }
 869
 870 out:
 871     if (gerr) {
 872         g_error_free(gerr);
 873     }
 874     if (keyfile) {
 875         g_key_file_free(keyfile);
 876     }
 877     g_free(data);
 878     return ret;
 879 }
 880
 881 static gboolean read_persistent_state(GAPersistentState *pstate,
 882                                       const gchar *path, gboolean frozen)
 883 {
 884     GKeyFile *keyfile = NULL;
 885     GError *gerr = NULL;
 886     struct stat st;
 887     gboolean ret = true;
 888
 889     g_assert(pstate);
 890
 891     if (stat(path, &st) == -1) {
 892         /* it's okay if state file doesn't exist, but any other error
 893          * indicates a permissions issue or some other misconfiguration
 894          * that we likely won't be able to recover from.
 895          */
 896         if (errno != ENOENT) {
 897             g_critical("unable to access state file at path %s: %s",
 898                        path, strerror(errno));
 899             ret = false;
 900             goto out;
 901         }
 902
 903         /* file doesn't exist. initialize state to default values and
 904          * attempt to save now. (we could wait till later when we have
 905          * modified state we need to commit, but if there's a problem,
 906          * such as a missing parent directory, we want to catch it now)
 907          *
 908          * there is a potential scenario where someone either managed to
 909          * update the agent from a version that didn't use a key store
 910          * while qemu-ga thought the filesystem was frozen, or
 911          * deleted the key store prior to issuing a fsfreeze, prior
 912          * to restarting the agent. in this case we go ahead and defer
 913          * initial creation till we actually have modified state to
 914          * write, otherwise fail to recover from freeze.
 915          */
 916         set_persistent_state_defaults(pstate);
 917         if (!frozen) {
 918             ret = write_persistent_state(pstate, path);
 919             if (!ret) {
 920                 g_critical("unable to create state file at path %s", path);
 921                 ret = false;
 922                 goto out;
 923             }
 924         }
 925         ret = true;
 926         goto out;
 927     }
 928
 929     keyfile = g_key_file_new();
 930     g_key_file_load_from_file(keyfile, path, 0, &gerr);
 931     if (gerr) {
 932         g_critical("error loading persistent state from path: %s, %s",
 933                    path, gerr->message);
 934         ret = false;
 935         goto out;
 936     }
 937
 938     persistent_state_from_keyfile(pstate, keyfile);
 939
 940 out:
 941     if (keyfile) {
 942         g_key_file_free(keyfile);
 943     }
 944     if (gerr) {
 945         g_error_free(gerr);
 946     }
 947
 948     return ret;
 949 }
 950
 951 int64_t ga_get_fd_handle(GAState *s, Error **errp)
 952 {
 953     int64_t handle;
 954
 955     g_assert(s->pstate_filepath);
 956     /*
 957      * We block commands and avoid operations that potentially require
 958      * writing to disk when we're in a frozen state. this includes opening
 959      * new files, so we should never get here in that situation
 960      */
 961     g_assert(!ga_is_frozen(s));
 962
 963     handle = s->pstate.fd_counter++;
 964
 965     /* This should never happen on a reasonable timeframe, as guest-file-open
 966      * would have to be issued 2^63 times */
 967     if (s->pstate.fd_counter == INT64_MAX) {
 968         abort();
 969     }
 970
 971     if (!write_persistent_state(&s->pstate, s->pstate_filepath)) {
 972         error_setg(errp, "failed to commit persistent state to disk");
 973         return -1;
 974     }
 975
 976     return handle;
 977 }
 978
 979 static void ga_print_cmd(const QmpCommand *cmd, void *opaque)
 980 {
 981     printf("%s\n", qmp_command_name(cmd));
 982 }
 983
 984 static GList *split_list(const gchar *str, const gchar *delim)
 985 {
 986     GList *list = NULL;
 987     int i;
 988     gchar **strv;
 989
 990     strv = g_strsplit(str, delim, -1);
 991     for (i = 0; strv[i]; i++) {
 992         list = g_list_prepend(list, strv[i]);
 993     }
 994     g_free(strv);
 995
 996     return list;
 997 }
 998
 999 struct GAConfig {
1000     char *channel_path;
1001     char *method;
1002     char *log_filepath;
1003     char *pid_filepath;
1004 #ifdef CONFIG_FSFREEZE
1005     char *fsfreeze_hook;
1006 #endif
1007     char *state_dir;
1008 #ifdef _WIN32
1009     const char *service;
1010 #endif
1011     gchar *bliststr; /* blockedrpcs may point to this string */
1012     gchar *aliststr; /* allowedrpcs may point to this string */
1013     GList *blockedrpcs;
1014     GList *allowedrpcs;
1015     int daemonize;
1016     GLogLevelFlags log_level;
1017     int dumpconf;
1018     bool retry_path;
1019 };
1020
1021 static void config_load(GAConfig *config)
1022 {
1023     GError *gerr = NULL;
1024     GKeyFile *keyfile;
1025     g_autofree char *conf = g_strdup(g_getenv("QGA_CONF")) ?: get_relocated_path(QGA_CONF_DEFAULT);
1026     const gchar *blockrpcs_key = "block-rpcs";
1027
1028     /* read system config */
1029     keyfile = g_key_file_new();
1030     if (!g_key_file_load_from_file(keyfile, conf, 0, &gerr)) {
1031         goto end;
1032     }
1033     if (g_key_file_has_key(keyfile, "general", "daemon", NULL)) {
1034         config->daemonize =
1035             g_key_file_get_boolean(keyfile, "general", "daemon", &gerr);
1036     }
1037     if (g_key_file_has_key(keyfile, "general", "method", NULL)) {
1038         config->method =
1039             g_key_file_get_string(keyfile, "general", "method", &gerr);
1040     }
1041     if (g_key_file_has_key(keyfile, "general", "path", NULL)) {
1042         config->channel_path =
1043             g_key_file_get_string(keyfile, "general", "path", &gerr);
1044     }
1045     if (g_key_file_has_key(keyfile, "general", "logfile", NULL)) {
1046         config->log_filepath =
1047             g_key_file_get_string(keyfile, "general", "logfile", &gerr);
1048     }
1049     if (g_key_file_has_key(keyfile, "general", "pidfile", NULL)) {
1050         config->pid_filepath =
1051             g_key_file_get_string(keyfile, "general", "pidfile", &gerr);
1052     }
1053 #ifdef CONFIG_FSFREEZE
1054     if (g_key_file_has_key(keyfile, "general", "fsfreeze-hook", NULL)) {
1055         config->fsfreeze_hook =
1056             g_key_file_get_string(keyfile,
1057                                   "general", "fsfreeze-hook", &gerr);
1058     }
1059 #endif
1060     if (g_key_file_has_key(keyfile, "general", "statedir", NULL)) {
1061         config->state_dir =
1062             g_key_file_get_string(keyfile, "general", "statedir", &gerr);
1063     }
1064     if (g_key_file_has_key(keyfile, "general", "verbose", NULL) &&
1065         g_key_file_get_boolean(keyfile, "general", "verbose", &gerr)) {
1066         /* enable all log levels */
1067         config->log_level = G_LOG_LEVEL_MASK;
1068     }
1069     if (g_key_file_has_key(keyfile, "general", "retry-path", NULL)) {
1070         config->retry_path =
1071             g_key_file_get_boolean(keyfile, "general", "retry-path", &gerr);
1072     }
1073
1074     if (g_key_file_has_key(keyfile, "general", blockrpcs_key, NULL)) {
1075         config->bliststr =
1076             g_key_file_get_string(keyfile, "general", blockrpcs_key, &gerr);
1077         config->blockedrpcs = g_list_concat(config->blockedrpcs,
1078                                           split_list(config->bliststr, ","));
1079     }
1080     if (g_key_file_has_key(keyfile, "general", "allow-rpcs", NULL)) {
1081         config->aliststr =
1082             g_key_file_get_string(keyfile, "general", "allow-rpcs", &gerr);
1083         config->allowedrpcs = g_list_concat(config->allowedrpcs,
1084                                           split_list(config->aliststr, ","));
1085     }
1086
1087     if (g_key_file_has_key(keyfile, "general", blockrpcs_key, NULL) &&
1088         g_key_file_has_key(keyfile, "general", "allow-rpcs", NULL)) {
1089         g_critical("wrong config, using 'block-rpcs' and 'allow-rpcs' keys at"
1090                    " the same time is not allowed");
1091         exit(EXIT_FAILURE);
1092     }
1093
1094 end:
1095     g_key_file_free(keyfile);
1096     if (gerr &&
1097         !(gerr->domain == G_FILE_ERROR && gerr->code == G_FILE_ERROR_NOENT)) {
1098         g_critical("error loading configuration from path: %s, %s",
1099                    conf, gerr->message);
1100         exit(EXIT_FAILURE);
1101     }
1102     g_clear_error(&gerr);
1103 }
1104
1105 static gchar *list_join(GList *list, const gchar separator)
1106 {
1107     GString *str = g_string_new("");
1108
1109     while (list) {
1110         str = g_string_append(str, (gchar *)list->data);
1111         list = g_list_next(list);
1112         if (list) {
1113             str = g_string_append_c(str, separator);
1114         }
1115     }
1116
1117     return g_string_free(str, FALSE);
1118 }
1119
1120 static void config_dump(GAConfig *config)
1121 {
1122     GError *error = NULL;
1123     GKeyFile *keyfile;
1124     gchar *tmp;
1125
1126     keyfile = g_key_file_new();
1127     g_assert(keyfile);
1128
1129     g_key_file_set_boolean(keyfile, "general", "daemon", config->daemonize);
1130     g_key_file_set_string(keyfile, "general", "method", config->method);
1131     if (config->channel_path) {
1132         g_key_file_set_string(keyfile, "general", "path", config->channel_path);
1133     }
1134     if (config->log_filepath) {
1135         g_key_file_set_string(keyfile, "general", "logfile",
1136                               config->log_filepath);
1137     }
1138     g_key_file_set_string(keyfile, "general", "pidfile", config->pid_filepath);
1139 #ifdef CONFIG_FSFREEZE
1140     if (config->fsfreeze_hook) {
1141         g_key_file_set_string(keyfile, "general", "fsfreeze-hook",
1142                               config->fsfreeze_hook);
1143     }
1144 #endif
1145     g_key_file_set_string(keyfile, "general", "statedir", config->state_dir);
1146     g_key_file_set_boolean(keyfile, "general", "verbose",
1147                            config->log_level == G_LOG_LEVEL_MASK);
1148     g_key_file_set_boolean(keyfile, "general", "retry-path",
1149                            config->retry_path);
1150     tmp = list_join(config->blockedrpcs, ',');
1151     g_key_file_set_string(keyfile, "general", "block-rpcs", tmp);
1152     g_free(tmp);
1153     tmp = list_join(config->allowedrpcs, ',');
1154     g_key_file_set_string(keyfile, "general", "allow-rpcs", tmp);
1155     g_free(tmp);
1156
1157     tmp = g_key_file_to_data(keyfile, NULL, &error);
1158     if (error) {
1159         g_critical("Failed to dump keyfile: %s", error->message);
1160         g_clear_error(&error);
1161     } else {
1162         printf("%s", tmp);
1163     }
1164
1165     g_free(tmp);
1166     g_key_file_free(keyfile);
1167 }
1168
1169 static void config_parse(GAConfig *config, int argc, char **argv)
1170 {
1171     const char *sopt = "hVvdm:p:l:f:F::b:a:s:t:Dr";
1172     int opt_ind = 0, ch;
1173     bool block_rpcs = false, allow_rpcs = false;
1174     const struct option lopt[] = {
1175         { "help", 0, NULL, 'h' },
1176         { "version", 0, NULL, 'V' },
1177         { "dump-conf", 0, NULL, 'D' },
1178         { "logfile", 1, NULL, 'l' },
1179         { "pidfile", 1, NULL, 'f' },
1180 #ifdef CONFIG_FSFREEZE
1181         { "fsfreeze-hook", 2, NULL, 'F' },
1182 #endif
1183         { "verbose", 0, NULL, 'v' },
1184         { "method", 1, NULL, 'm' },
1185         { "path", 1, NULL, 'p' },
1186         { "daemonize", 0, NULL, 'd' },
1187         { "block-rpcs", 1, NULL, 'b' },
1188         { "allow-rpcs", 1, NULL, 'a' },
1189 #ifdef _WIN32
1190         { "service", 1, NULL, 's' },
1191 #endif
1192         { "statedir", 1, NULL, 't' },
1193         { "retry-path", 0, NULL, 'r' },
1194         { NULL, 0, NULL, 0 }
1195     };
1196
1197     while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
1198         switch (ch) {
1199         case 'm':
1200             g_free(config->method);
1201             config->method = g_strdup(optarg);
1202             break;
1203         case 'p':
1204             g_free(config->channel_path);
1205             config->channel_path = g_strdup(optarg);
1206             break;
1207         case 'l':
1208             g_free(config->log_filepath);
1209             config->log_filepath = g_strdup(optarg);
1210             break;
1211         case 'f':
1212             g_free(config->pid_filepath);
1213             config->pid_filepath = g_strdup(optarg);
1214             break;
1215 #ifdef CONFIG_FSFREEZE
1216         case 'F':
1217             g_free(config->fsfreeze_hook);
1218             config->fsfreeze_hook = optarg ? g_strdup(optarg) : get_relocated_path(QGA_FSFREEZE_HOOK_DEFAULT);
1219             break;
1220 #endif
1221         case 't':
1222             g_free(config->state_dir);
1223             config->state_dir = g_strdup(optarg);
1224             break;
1225         case 'v':
1226             /* enable all log levels */
1227             config->log_level = G_LOG_LEVEL_MASK;
1228             break;
1229         case 'V':
1230             printf("QEMU Guest Agent %s\n", QEMU_VERSION);
1231             exit(EXIT_SUCCESS);
1232         case 'd':
1233             config->daemonize = 1;
1234             break;
1235         case 'D':
1236             config->dumpconf = 1;
1237             break;
1238         case 'r':
1239             config->retry_path = true;
1240             break;
1241         case 'b': {
1242             if (is_help_option(optarg)) {
1243                 qmp_for_each_command(&ga_commands, ga_print_cmd, NULL);
1244                 exit(EXIT_SUCCESS);
1245             }
1246             config->blockedrpcs = g_list_concat(config->blockedrpcs,
1247                                                 split_list(optarg, ","));
1248             block_rpcs = true;
1249             break;
1250         }
1251         case 'a': {
1252             if (is_help_option(optarg)) {
1253                 qmp_for_each_command(&ga_commands, ga_print_cmd, NULL);
1254                 exit(EXIT_SUCCESS);
1255             }
1256             config->allowedrpcs = g_list_concat(config->allowedrpcs,
1257                                                 split_list(optarg, ","));
1258             allow_rpcs = true;
1259             break;
1260         }
1261 #ifdef _WIN32
1262         case 's':
1263             config->service = optarg;
1264             if (strcmp(config->service, "install") == 0) {
1265                 if (ga_install_vss_provider()) {
1266                     exit(EXIT_FAILURE);
1267                 }
1268                 if (ga_install_service(config->channel_path,
1269                                        config->log_filepath, config->state_dir)) {
1270                     exit(EXIT_FAILURE);
1271                 }
1272                 exit(EXIT_SUCCESS);
1273             } else if (strcmp(config->service, "uninstall") == 0) {
1274                 ga_uninstall_vss_provider();
1275                 exit(ga_uninstall_service());
1276             } else if (strcmp(config->service, "vss-install") == 0) {
1277                 if (ga_install_vss_provider()) {
1278                     exit(EXIT_FAILURE);
1279                 }
1280                 exit(EXIT_SUCCESS);
1281             } else if (strcmp(config->service, "vss-uninstall") == 0) {
1282                 ga_uninstall_vss_provider();
1283                 exit(EXIT_SUCCESS);
1284             } else {
1285                 printf("Unknown service command.\n");
1286                 exit(EXIT_FAILURE);
1287             }
1288             break;
1289 #endif
1290         case 'h':
1291             usage(argv[0]);
1292             exit(EXIT_SUCCESS);
1293         case '?':
1294             g_print("Unknown option, try '%s --help' for more information.\n",
1295                     argv[0]);
1296             exit(EXIT_FAILURE);
1297         }
1298     }
1299
1300     if (block_rpcs && allow_rpcs) {
1301         g_critical("wrong commandline, using --block-rpcs and --allow-rpcs at the"
1302                    " same time is not allowed");
1303         exit(EXIT_FAILURE);
1304     }
1305 }
1306
1307 static void config_free(GAConfig *config)
1308 {
1309     g_free(config->method);
1310     g_free(config->log_filepath);
1311     g_free(config->pid_filepath);
1312     g_free(config->state_dir);
1313     g_free(config->channel_path);
1314     g_free(config->bliststr);
1315     g_free(config->aliststr);
1316 #ifdef CONFIG_FSFREEZE
1317     g_free(config->fsfreeze_hook);
1318 #endif
1319     g_list_free_full(config->blockedrpcs, g_free);
1320     g_list_free_full(config->allowedrpcs, g_free);
1321     g_free(config);
1322 }
1323
1324 static bool check_is_frozen(GAState *s)
1325 {
1326 #ifndef _WIN32
1327     /* check if a previous instance of qemu-ga exited with filesystems' state
1328      * marked as frozen. this could be a stale value (a non-qemu-ga process
1329      * or reboot may have since unfrozen them), but better to require an
1330      * unneeded unfreeze than to risk hanging on start-up
1331      */
1332     struct stat st;
1333     if (stat(s->state_filepath_isfrozen, &st) == -1) {
1334         /* it's okay if the file doesn't exist, but if we can't access for
1335          * some other reason, such as permissions, there's a configuration
1336          * that needs to be addressed. so just bail now before we get into
1337          * more trouble later
1338          */
1339         if (errno != ENOENT) {
1340             g_critical("unable to access state file at path %s: %s",
1341                        s->state_filepath_isfrozen, strerror(errno));
1342             return EXIT_FAILURE;
1343         }
1344     } else {
1345         g_warning("previous instance appears to have exited with frozen"
1346                   " filesystems. deferring logging/pidfile creation and"
1347                   " disabling non-fsfreeze-safe commands until"
1348                   " guest-fsfreeze-thaw is issued, or filesystems are"
1349                   " manually unfrozen and the file %s is removed",
1350                   s->state_filepath_isfrozen);
1351         return true;
1352     }
1353 #endif
1354     return false;
1355 }
1356
1357 static GAState *initialize_agent(GAConfig *config, int socket_activation)
1358 {
1359     GAState *s = g_new0(GAState, 1);
1360
1361     g_assert(ga_state == NULL);
1362
1363     s->log_level = config->log_level;
1364     s->log_file = stderr;
1365 #ifdef CONFIG_FSFREEZE
1366     s->fsfreeze_hook = config->fsfreeze_hook;
1367 #endif
1368     s->pstate_filepath = g_strdup_printf("%s/qga.state", config->state_dir);
1369     s->state_filepath_isfrozen = g_strdup_printf("%s/qga.state.isfrozen",
1370                                                  config->state_dir);
1371     s->frozen = check_is_frozen(s);
1372
1373     g_log_set_default_handler(ga_log, s);
1374     g_log_set_fatal_mask(NULL, G_LOG_LEVEL_ERROR);
1375     ga_enable_logging(s);
1376
1377     g_debug("Guest agent version %s started", QEMU_FULL_VERSION);
1378
1379 #ifdef _WIN32
1380     s->event_log = RegisterEventSource(NULL, "qemu-ga");
1381     if (!s->event_log) {
1382         g_autofree gchar *errmsg = g_win32_error_message(GetLastError());
1383         g_critical("unable to register event source: %s", errmsg);
1384         return NULL;
1385     }
1386
1387     /* On win32 the state directory is application specific (be it the default
1388      * or a user override). We got past the command line parsing; let's create
1389      * the directory (with any intermediate directories). If we run into an
1390      * error later on, we won't try to clean up the directory, it is considered
1391      * persistent.
1392      */
1393     if (g_mkdir_with_parents(config->state_dir, S_IRWXU) == -1) {
1394         g_critical("unable to create (an ancestor of) the state directory"
1395                    " '%s': %s", config->state_dir, strerror(errno));
1396         return NULL;
1397     }
1398 #endif
1399
1400     if (ga_is_frozen(s)) {
1401         if (config->daemonize) {
1402             /* delay opening/locking of pidfile till filesystems are unfrozen */
1403             s->deferred_options.pid_filepath = config->pid_filepath;
1404             become_daemon(NULL);
1405         }
1406         if (config->log_filepath) {
1407             /* delay opening the log file till filesystems are unfrozen */
1408             s->deferred_options.log_filepath = config->log_filepath;
1409         }
1410         ga_disable_logging(s);
1411         qmp_for_each_command(&ga_commands, ga_disable_not_allowed_freeze, NULL);
1412     } else {
1413         if (config->daemonize) {
1414             become_daemon(config->pid_filepath);
1415         }
1416         if (config->log_filepath) {
1417             FILE *log_file = ga_open_logfile(config->log_filepath);
1418             if (!log_file) {
1419                 g_critical("unable to open specified log file: %s",
1420                            strerror(errno));
1421                 return NULL;
1422             }
1423             s->log_file = log_file;
1424         }
1425     }
1426
1427     /* load persistent state from disk */
1428     if (!read_persistent_state(&s->pstate,
1429                                s->pstate_filepath,
1430                                ga_is_frozen(s))) {
1431         g_critical("failed to load persistent state");
1432         return NULL;
1433     }
1434
1435     if (config->allowedrpcs) {
1436         qmp_for_each_command(&ga_commands, ga_disable_not_allowed, config->allowedrpcs);
1437         s->allowedrpcs = config->allowedrpcs;
1438     }
1439
1440     /*
1441      * Some commands can be blocked due to system limitation.
1442      * Initialize blockedrpcs list even if allowedrpcs specified.
1443      */
1444     config->blockedrpcs = ga_command_init_blockedrpcs(config->blockedrpcs);
1445     if (config->blockedrpcs) {
1446         GList *l = config->blockedrpcs;
1447         s->blockedrpcs = config->blockedrpcs;
1448         do {
1449             g_debug("disabling command: %s", (char *)l->data);
1450             qmp_disable_command(&ga_commands, l->data, NULL);
1451             l = g_list_next(l);
1452         } while (l);
1453     }
1454     s->command_state = ga_command_state_new();
1455     ga_command_state_init(s, s->command_state);
1456     ga_command_state_init_all(s->command_state);
1457     json_message_parser_init(&s->parser, process_event, s, NULL);
1458
1459 #ifndef _WIN32
1460     if (!register_signal_handlers()) {
1461         g_critical("failed to register signal handlers");
1462         return NULL;
1463     }
1464 #endif
1465
1466     s->main_loop = g_main_loop_new(NULL, false);
1467
1468     s->config = config;
1469     s->socket_activation = socket_activation;
1470
1471 #ifdef _WIN32
1472     s->wakeup_event = CreateEvent(NULL, TRUE, FALSE, TEXT("WakeUp"));
1473     if (s->wakeup_event == NULL) {
1474         g_critical("CreateEvent failed");
1475         return NULL;
1476     }
1477 #endif
1478
1479     ga_state = s;
1480     return s;
1481 }
1482
1483 static void cleanup_agent(GAState *s)
1484 {
1485 #ifdef _WIN32
1486     CloseHandle(s->wakeup_event);
1487     CloseHandle(s->event_log);
1488 #endif
1489     if (s->command_state) {
1490         ga_command_state_cleanup_all(s->command_state);
1491         ga_command_state_free(s->command_state);
1492         json_message_parser_destroy(&s->parser);
1493     }
1494     g_free(s->pstate_filepath);
1495     g_free(s->state_filepath_isfrozen);
1496     if (s->main_loop) {
1497         g_main_loop_unref(s->main_loop);
1498     }
1499     g_free(s);
1500     ga_state = NULL;
1501 }
1502
1503 static int run_agent_once(GAState *s)
1504 {
1505     if (!channel_init(s, s->config->method, s->config->channel_path,
1506                       s->socket_activation ? FIRST_SOCKET_ACTIVATION_FD : -1)) {
1507         g_critical("failed to initialize guest agent channel");
1508         return EXIT_FAILURE;
1509     }
1510
1511     g_main_loop_run(ga_state->main_loop);
1512
1513     if (s->channel) {
1514         ga_channel_free(s->channel);
1515     }
1516
1517     return EXIT_SUCCESS;
1518 }
1519
1520 static void wait_for_channel_availability(GAState *s)
1521 {
1522     g_warning("waiting for channel path...");
1523 #ifndef _WIN32
1524     sleep(QGA_RETRY_INTERVAL);
1525 #else
1526     DWORD dwWaitResult;
1527
1528     dwWaitResult = WaitForSingleObject(s->wakeup_event, INFINITE);
1529
1530     switch (dwWaitResult) {
1531     case WAIT_OBJECT_0:
1532         break;
1533     case WAIT_TIMEOUT:
1534         break;
1535     default:
1536         g_critical("WaitForSingleObject failed");
1537     }
1538 #endif
1539 }
1540
1541 static int run_agent(GAState *s)
1542 {
1543     int ret = EXIT_SUCCESS;
1544
1545     s->force_exit = false;
1546
1547     do {
1548         ret = run_agent_once(s);
1549         if (s->config->retry_path && !s->force_exit) {
1550             g_warning("agent stopped unexpectedly, restarting...");
1551             wait_for_channel_availability(s);
1552         }
1553     } while (s->config->retry_path && !s->force_exit);
1554
1555     return ret;
1556 }
1557
1558 static void stop_agent(GAState *s, bool requested)
1559 {
1560     if (!s->force_exit) {
1561         s->force_exit = requested;
1562     }
1563
1564     if (g_main_loop_is_running(s->main_loop)) {
1565         g_main_loop_quit(s->main_loop);
1566     }
1567 }
1568
1569 int main(int argc, char **argv)
1570 {
1571     int ret = EXIT_SUCCESS;
1572     GAState *s;
1573     GAConfig *config = g_new0(GAConfig, 1);
1574     int socket_activation;
1575
1576     config->log_level = G_LOG_LEVEL_ERROR | G_LOG_LEVEL_CRITICAL;
1577
1578     qemu_init_exec_dir(argv[0]);
1579     qga_qmp_init_marshal(&ga_commands);
1580
1581     init_dfl_pathnames();
1582     config_load(config);
1583     config_parse(config, argc, argv);
1584
1585     if (config->pid_filepath == NULL) {
1586         config->pid_filepath = g_strdup(dfl_pathnames.pidfile);
1587     }
1588
1589     if (config->state_dir == NULL) {
1590         config->state_dir = g_strdup(dfl_pathnames.state_dir);
1591     }
1592
1593     if (config->method == NULL) {
1594         config->method = g_strdup("virtio-serial");
1595     }
1596
1597     socket_activation = check_socket_activation();
1598     if (socket_activation > 1) {
1599         g_critical("qemu-ga only supports listening on one socket");
1600         ret = EXIT_FAILURE;
1601         goto end;
1602     }
1603     if (socket_activation) {
1604         SocketAddress *addr;
1605
1606         g_free(config->method);
1607         g_free(config->channel_path);
1608         config->method = NULL;
1609         config->channel_path = NULL;
1610
1611         addr = socket_local_address(FIRST_SOCKET_ACTIVATION_FD, NULL);
1612         if (addr) {
1613             if (addr->type == SOCKET_ADDRESS_TYPE_UNIX) {
1614                 config->method = g_strdup("unix-listen");
1615             } else if (addr->type == SOCKET_ADDRESS_TYPE_VSOCK) {
1616                 config->method = g_strdup("vsock-listen");
1617             }
1618
1619             qapi_free_SocketAddress(addr);
1620         }
1621
1622         if (!config->method) {
1623             g_critical("unsupported listen fd type");
1624             ret = EXIT_FAILURE;
1625             goto end;
1626         }
1627     } else if (config->channel_path == NULL) {
1628         if (strcmp(config->method, "virtio-serial") == 0) {
1629             /* try the default path for the virtio-serial port */
1630             config->channel_path = g_strdup(QGA_VIRTIO_PATH_DEFAULT);
1631         } else if (strcmp(config->method, "isa-serial") == 0) {
1632             /* try the default path for the serial port - COM1 */
1633             config->channel_path = g_strdup(QGA_SERIAL_PATH_DEFAULT);
1634         } else {
1635             g_critical("must specify a path for this channel");
1636             ret = EXIT_FAILURE;
1637             goto end;
1638         }
1639     }
1640
1641     if (config->dumpconf) {
1642         config_dump(config);
1643         goto end;
1644     }
1645
1646     s = initialize_agent(config, socket_activation);
1647     if (!s) {
1648         g_critical("error initializing guest agent");
1649         goto end;
1650     }
1651
1652 #ifdef _WIN32
1653     if (config->daemonize) {
1654         SERVICE_TABLE_ENTRY service_table[] = {
1655             { (char *)QGA_SERVICE_NAME, service_main }, { NULL, NULL } };
1656         StartServiceCtrlDispatcher(service_table);
1657     } else {
1658         ret = run_agent(s);
1659     }
1660 #else
1661     ret = run_agent(s);
1662 #endif
1663
1664     cleanup_agent(s);
1665
1666 end:
1667     if (config->daemonize) {
1668         unlink(config->pid_filepath);
1669     }
1670
1671     config_free(config);
1672
1673     return ret;
1674 }