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 #include <stdlib.h>
  14 #include <stdio.h>
  15 #include <stdbool.h>
  16 #include <glib.h>
  17 #include <getopt.h>
  18 #include <glib/gstdio.h>
  19 #ifndef _WIN32
  20 #include <syslog.h>
  21 #include <sys/wait.h>
  22 #include <sys/stat.h>
  23 #endif
  24 #include "qapi/qmp/json-streamer.h"
  25 #include "qapi/qmp/json-parser.h"
  26 #include "qapi/qmp/qint.h"
  27 #include "qapi/qmp/qjson.h"
  28 #include "qga/guest-agent-core.h"
  29 #include "qemu/module.h"
  30 #include "signal.h"
  31 #include "qapi/qmp/qerror.h"
  32 #include "qapi/qmp/dispatch.h"
  33 #include "qga/channel.h"
  34 #include "qemu/bswap.h"
  35 #ifdef _WIN32
  36 #include "qga/service-win32.h"
  37 #include "qga/vss-win32.h"
  38 #endif
  39 #ifdef __linux__
  40 #include <linux/fs.h>
  41 #ifdef FIFREEZE
  42 #define CONFIG_FSFREEZE
  43 #endif
  44 #endif
  45
  46 #ifndef _WIN32
  47 #define QGA_VIRTIO_PATH_DEFAULT "/dev/virtio-ports/org.qemu.guest_agent.0"
  48 #define QGA_STATE_RELATIVE_DIR  "run"
  49 #define QGA_SERIAL_PATH_DEFAULT "/dev/ttyS0"
  50 #else
  51 #define QGA_VIRTIO_PATH_DEFAULT "\\\\.\\Global\\org.qemu.guest_agent.0"
  52 #define QGA_STATE_RELATIVE_DIR  "qemu-ga"
  53 #define QGA_SERIAL_PATH_DEFAULT "COM1"
  54 #endif
  55 #ifdef CONFIG_FSFREEZE
  56 #define QGA_FSFREEZE_HOOK_DEFAULT CONFIG_QEMU_CONFDIR "/fsfreeze-hook"
  57 #endif
  58 #define QGA_SENTINEL_BYTE 0xFF
  59
  60 static struct {
  61     const char *state_dir;
  62     const char *pidfile;
  63 } dfl_pathnames;
  64
  65 typedef struct GAPersistentState {
  66 #define QGA_PSTATE_DEFAULT_FD_COUNTER 1000
  67     int64_t fd_counter;
  68 } GAPersistentState;
  69
  70 struct GAState {
  71     JSONMessageParser parser;
  72     GMainLoop *main_loop;
  73     GAChannel *channel;
  74     bool virtio; /* fastpath to check for virtio to deal with poll() quirks */
  75     GACommandState *command_state;
  76     GLogLevelFlags log_level;
  77     FILE *log_file;
  78     bool logging_enabled;
  79 #ifdef _WIN32
  80     GAService service;
  81 #endif
  82     bool delimit_response;
  83     bool frozen;
  84     GList *blacklist;
  85     const char *state_filepath_isfrozen;
  86     struct {
  87         const char *log_filepath;
  88         const char *pid_filepath;
  89     } deferred_options;
  90 #ifdef CONFIG_FSFREEZE
  91     const char *fsfreeze_hook;
  92 #endif
  93     const gchar *pstate_filepath;
  94     GAPersistentState pstate;
  95 };
  96
  97 struct GAState *ga_state;
  98
  99 /* commands that are safe to issue while filesystems are frozen */
 100 static const char *ga_freeze_whitelist[] = {
 101     "guest-ping",
 102     "guest-info",
 103     "guest-sync",
 104     "guest-sync-delimited",
 105     "guest-fsfreeze-status",
 106     "guest-fsfreeze-thaw",
 107     NULL
 108 };
 109
 110 #ifdef _WIN32
 111 DWORD WINAPI service_ctrl_handler(DWORD ctrl, DWORD type, LPVOID data,
 112                                   LPVOID ctx);
 113 VOID WINAPI service_main(DWORD argc, TCHAR *argv[]);
 114 #endif
 115
 116 static void
 117 init_dfl_pathnames(void)
 118 {
 119     g_assert(dfl_pathnames.state_dir == NULL);
 120     g_assert(dfl_pathnames.pidfile == NULL);
 121     dfl_pathnames.state_dir = qemu_get_local_state_pathname(
 122       QGA_STATE_RELATIVE_DIR);
 123     dfl_pathnames.pidfile   = qemu_get_local_state_pathname(
 124       QGA_STATE_RELATIVE_DIR G_DIR_SEPARATOR_S "qemu-ga.pid");
 125 }
 126
 127 static void quit_handler(int sig)
 128 {
 129     /* if we're frozen, don't exit unless we're absolutely forced to,
 130      * because it's basically impossible for graceful exit to complete
 131      * unless all log/pid files are on unfreezable filesystems. there's
 132      * also a very likely chance killing the agent before unfreezing
 133      * the filesystems is a mistake (or will be viewed as one later).
 134      */
 135     if (ga_is_frozen(ga_state)) {
 136         return;
 137     }
 138     g_debug("received signal num %d, quitting", sig);
 139
 140     if (g_main_loop_is_running(ga_state->main_loop)) {
 141         g_main_loop_quit(ga_state->main_loop);
 142     }
 143 }
 144
 145 #ifndef _WIN32
 146 static gboolean register_signal_handlers(void)
 147 {
 148     struct sigaction sigact;
 149     int ret;
 150
 151     memset(&sigact, 0, sizeof(struct sigaction));
 152     sigact.sa_handler = quit_handler;
 153
 154     ret = sigaction(SIGINT, &sigact, NULL);
 155     if (ret == -1) {
 156         g_error("error configuring signal handler: %s", strerror(errno));
 157     }
 158     ret = sigaction(SIGTERM, &sigact, NULL);
 159     if (ret == -1) {
 160         g_error("error configuring signal handler: %s", strerror(errno));
 161     }
 162
 163     return true;
 164 }
 165
 166 /* TODO: use this in place of all post-fork() fclose(std*) callers */
 167 void reopen_fd_to_null(int fd)
 168 {
 169     int nullfd;
 170
 171     nullfd = open("/dev/null", O_RDWR);
 172     if (nullfd < 0) {
 173         return;
 174     }
 175
 176     dup2(nullfd, fd);
 177
 178     if (nullfd != fd) {
 179         close(nullfd);
 180     }
 181 }
 182 #endif
 183
 184 static void usage(const char *cmd)
 185 {
 186     printf(
 187 "Usage: %s [-m <method> -p <path>] [<options>]\n"
 188 "QEMU Guest Agent %s\n"
 189 "\n"
 190 "  -m, --method      transport method: one of unix-listen, virtio-serial, or\n"
 191 "                    isa-serial (virtio-serial is the default)\n"
 192 "  -p, --path        device/socket path (the default for virtio-serial is:\n"
 193 "                    %s,\n"
 194 "                    the default for isa-serial is:\n"
 195 "                    %s)\n"
 196 "  -l, --logfile     set logfile path, logs to stderr by default\n"
 197 "  -f, --pidfile     specify pidfile (default is %s)\n"
 198 #ifdef CONFIG_FSFREEZE
 199 "  -F, --fsfreeze-hook\n"
 200 "                    enable fsfreeze hook. Accepts an optional argument that\n"
 201 "                    specifies script to run on freeze/thaw. Script will be\n"
 202 "                    called with 'freeze'/'thaw' arguments accordingly.\n"
 203 "                    (default is %s)\n"
 204 "                    If using -F with an argument, do not follow -F with a\n"
 205 "                    space.\n"
 206 "                    (for example: -F/var/run/fsfreezehook.sh)\n"
 207 #endif
 208 "  -t, --statedir    specify dir to store state information (absolute paths\n"
 209 "                    only, default is %s)\n"
 210 "  -v, --verbose     log extra debugging information\n"
 211 "  -V, --version     print version information and exit\n"
 212 "  -d, --daemonize   become a daemon\n"
 213 #ifdef _WIN32
 214 "  -s, --service     service commands: install, uninstall\n"
 215 #endif
 216 "  -b, --blacklist   comma-separated list of RPCs to disable (no spaces, \"?\"\n"
 217 "                    to list available RPCs)\n"
 218 "  -h, --help        display this help and exit\n"
 219 "\n"
 220 "Report bugs to <mdroth@linux.vnet.ibm.com>\n"
 221     , cmd, QEMU_VERSION, QGA_VIRTIO_PATH_DEFAULT, QGA_SERIAL_PATH_DEFAULT,
 222     dfl_pathnames.pidfile,
 223 #ifdef CONFIG_FSFREEZE
 224     QGA_FSFREEZE_HOOK_DEFAULT,
 225 #endif
 226     dfl_pathnames.state_dir);
 227 }
 228
 229 static const char *ga_log_level_str(GLogLevelFlags level)
 230 {
 231     switch (level & G_LOG_LEVEL_MASK) {
 232         case G_LOG_LEVEL_ERROR:
 233             return "error";
 234         case G_LOG_LEVEL_CRITICAL:
 235             return "critical";
 236         case G_LOG_LEVEL_WARNING:
 237             return "warning";
 238         case G_LOG_LEVEL_MESSAGE:
 239             return "message";
 240         case G_LOG_LEVEL_INFO:
 241             return "info";
 242         case G_LOG_LEVEL_DEBUG:
 243             return "debug";
 244         default:
 245             return "user";
 246     }
 247 }
 248
 249 bool ga_logging_enabled(GAState *s)
 250 {
 251     return s->logging_enabled;
 252 }
 253
 254 void ga_disable_logging(GAState *s)
 255 {
 256     s->logging_enabled = false;
 257 }
 258
 259 void ga_enable_logging(GAState *s)
 260 {
 261     s->logging_enabled = true;
 262 }
 263
 264 static void ga_log(const gchar *domain, GLogLevelFlags level,
 265                    const gchar *msg, gpointer opaque)
 266 {
 267     GAState *s = opaque;
 268     GTimeVal time;
 269     const char *level_str = ga_log_level_str(level);
 270
 271     if (!ga_logging_enabled(s)) {
 272         return;
 273     }
 274
 275     level &= G_LOG_LEVEL_MASK;
 276 #ifndef _WIN32
 277     if (domain && strcmp(domain, "syslog") == 0) {
 278         syslog(LOG_INFO, "%s: %s", level_str, msg);
 279     } else if (level & s->log_level) {
 280 #else
 281     if (level & s->log_level) {
 282 #endif
 283         g_get_current_time(&time);
 284         fprintf(s->log_file,
 285                 "%lu.%lu: %s: %s\n", time.tv_sec, time.tv_usec, level_str, msg);
 286         fflush(s->log_file);
 287     }
 288 }
 289
 290 void ga_set_response_delimited(GAState *s)
 291 {
 292     s->delimit_response = true;
 293 }
 294
 295 static FILE *ga_open_logfile(const char *logfile)
 296 {
 297     FILE *f;
 298
 299     f = fopen(logfile, "a");
 300     if (!f) {
 301         return NULL;
 302     }
 303
 304     qemu_set_cloexec(fileno(f));
 305     return f;
 306 }
 307
 308 #ifndef _WIN32
 309 static bool ga_open_pidfile(const char *pidfile)
 310 {
 311     int pidfd;
 312     char pidstr[32];
 313
 314     pidfd = qemu_open(pidfile, O_CREAT|O_WRONLY, S_IRUSR|S_IWUSR);
 315     if (pidfd == -1 || lockf(pidfd, F_TLOCK, 0)) {
 316         g_critical("Cannot lock pid file, %s", strerror(errno));
 317         if (pidfd != -1) {
 318             close(pidfd);
 319         }
 320         return false;
 321     }
 322
 323     if (ftruncate(pidfd, 0)) {
 324         g_critical("Failed to truncate pid file");
 325         goto fail;
 326     }
 327     snprintf(pidstr, sizeof(pidstr), "%d\n", getpid());
 328     if (write(pidfd, pidstr, strlen(pidstr)) != strlen(pidstr)) {
 329         g_critical("Failed to write pid file");
 330         goto fail;
 331     }
 332
 333     /* keep pidfile open & locked forever */
 334     return true;
 335
 336 fail:
 337     unlink(pidfile);
 338     close(pidfd);
 339     return false;
 340 }
 341 #else /* _WIN32 */
 342 static bool ga_open_pidfile(const char *pidfile)
 343 {
 344     return true;
 345 }
 346 #endif
 347
 348 static gint ga_strcmp(gconstpointer str1, gconstpointer str2)
 349 {
 350     return strcmp(str1, str2);
 351 }
 352
 353 /* disable commands that aren't safe for fsfreeze */
 354 static void ga_disable_non_whitelisted(QmpCommand *cmd, void *opaque)
 355 {
 356     bool whitelisted = false;
 357     int i = 0;
 358     const char *name = qmp_command_name(cmd);
 359
 360     while (ga_freeze_whitelist[i] != NULL) {
 361         if (strcmp(name, ga_freeze_whitelist[i]) == 0) {
 362             whitelisted = true;
 363         }
 364         i++;
 365     }
 366     if (!whitelisted) {
 367         g_debug("disabling command: %s", name);
 368         qmp_disable_command(name);
 369     }
 370 }
 371
 372 /* [re-]enable all commands, except those explicitly blacklisted by user */
 373 static void ga_enable_non_blacklisted(QmpCommand *cmd, void *opaque)
 374 {
 375     GList *blacklist = opaque;
 376     const char *name = qmp_command_name(cmd);
 377
 378     if (g_list_find_custom(blacklist, name, ga_strcmp) == NULL &&
 379         !qmp_command_is_enabled(cmd)) {
 380         g_debug("enabling command: %s", name);
 381         qmp_enable_command(name);
 382     }
 383 }
 384
 385 static bool ga_create_file(const char *path)
 386 {
 387     int fd = open(path, O_CREAT | O_WRONLY, S_IWUSR | S_IRUSR);
 388     if (fd == -1) {
 389         g_warning("unable to open/create file %s: %s", path, strerror(errno));
 390         return false;
 391     }
 392     close(fd);
 393     return true;
 394 }
 395
 396 static bool ga_delete_file(const char *path)
 397 {
 398     int ret = unlink(path);
 399     if (ret == -1) {
 400         g_warning("unable to delete file: %s: %s", path, strerror(errno));
 401         return false;
 402     }
 403
 404     return true;
 405 }
 406
 407 bool ga_is_frozen(GAState *s)
 408 {
 409     return s->frozen;
 410 }
 411
 412 void ga_set_frozen(GAState *s)
 413 {
 414     if (ga_is_frozen(s)) {
 415         return;
 416     }
 417     /* disable all non-whitelisted (for frozen state) commands */
 418     qmp_for_each_command(ga_disable_non_whitelisted, NULL);
 419     g_warning("disabling logging due to filesystem freeze");
 420     ga_disable_logging(s);
 421     s->frozen = true;
 422     if (!ga_create_file(s->state_filepath_isfrozen)) {
 423         g_warning("unable to create %s, fsfreeze may not function properly",
 424                   s->state_filepath_isfrozen);
 425     }
 426 }
 427
 428 void ga_unset_frozen(GAState *s)
 429 {
 430     if (!ga_is_frozen(s)) {
 431         return;
 432     }
 433
 434     /* if we delayed creation/opening of pid/log files due to being
 435      * in a frozen state at start up, do it now
 436      */
 437     if (s->deferred_options.log_filepath) {
 438         s->log_file = ga_open_logfile(s->deferred_options.log_filepath);
 439         if (!s->log_file) {
 440             s->log_file = stderr;
 441         }
 442         s->deferred_options.log_filepath = NULL;
 443     }
 444     ga_enable_logging(s);
 445     g_warning("logging re-enabled due to filesystem unfreeze");
 446     if (s->deferred_options.pid_filepath) {
 447         if (!ga_open_pidfile(s->deferred_options.pid_filepath)) {
 448             g_warning("failed to create/open pid file");
 449         }
 450         s->deferred_options.pid_filepath = NULL;
 451     }
 452
 453     /* enable all disabled, non-blacklisted commands */
 454     qmp_for_each_command(ga_enable_non_blacklisted, s->blacklist);
 455     s->frozen = false;
 456     if (!ga_delete_file(s->state_filepath_isfrozen)) {
 457         g_warning("unable to delete %s, fsfreeze may not function properly",
 458                   s->state_filepath_isfrozen);
 459     }
 460 }
 461
 462 #ifdef CONFIG_FSFREEZE
 463 const char *ga_fsfreeze_hook(GAState *s)
 464 {
 465     return s->fsfreeze_hook;
 466 }
 467 #endif
 468
 469 static void become_daemon(const char *pidfile)
 470 {
 471 #ifndef _WIN32
 472     pid_t pid, sid;
 473
 474     pid = fork();
 475     if (pid < 0) {
 476         exit(EXIT_FAILURE);
 477     }
 478     if (pid > 0) {
 479         exit(EXIT_SUCCESS);
 480     }
 481
 482     if (pidfile) {
 483         if (!ga_open_pidfile(pidfile)) {
 484             g_critical("failed to create pidfile");
 485             exit(EXIT_FAILURE);
 486         }
 487     }
 488
 489     umask(S_IRWXG | S_IRWXO);
 490     sid = setsid();
 491     if (sid < 0) {
 492         goto fail;
 493     }
 494     if ((chdir("/")) < 0) {
 495         goto fail;
 496     }
 497
 498     reopen_fd_to_null(STDIN_FILENO);
 499     reopen_fd_to_null(STDOUT_FILENO);
 500     reopen_fd_to_null(STDERR_FILENO);
 501     return;
 502
 503 fail:
 504     if (pidfile) {
 505         unlink(pidfile);
 506     }
 507     g_critical("failed to daemonize");
 508     exit(EXIT_FAILURE);
 509 #endif
 510 }
 511
 512 static int send_response(GAState *s, QObject *payload)
 513 {
 514     const char *buf;
 515     QString *payload_qstr, *response_qstr;
 516     GIOStatus status;
 517
 518     g_assert(payload && s->channel);
 519
 520     payload_qstr = qobject_to_json(payload);
 521     if (!payload_qstr) {
 522         return -EINVAL;
 523     }
 524
 525     if (s->delimit_response) {
 526         s->delimit_response = false;
 527         response_qstr = qstring_new();
 528         qstring_append_chr(response_qstr, QGA_SENTINEL_BYTE);
 529         qstring_append(response_qstr, qstring_get_str(payload_qstr));
 530         QDECREF(payload_qstr);
 531     } else {
 532         response_qstr = payload_qstr;
 533     }
 534
 535     qstring_append_chr(response_qstr, '\n');
 536     buf = qstring_get_str(response_qstr);
 537     status = ga_channel_write_all(s->channel, buf, strlen(buf));
 538     QDECREF(response_qstr);
 539     if (status != G_IO_STATUS_NORMAL) {
 540         return -EIO;
 541     }
 542
 543     return 0;
 544 }
 545
 546 static void process_command(GAState *s, QDict *req)
 547 {
 548     QObject *rsp = NULL;
 549     int ret;
 550
 551     g_assert(req);
 552     g_debug("processing command");
 553     rsp = qmp_dispatch(QOBJECT(req));
 554     if (rsp) {
 555         ret = send_response(s, rsp);
 556         if (ret) {
 557             g_warning("error sending response: %s", strerror(ret));
 558         }
 559         qobject_decref(rsp);
 560     }
 561 }
 562
 563 /* handle requests/control events coming in over the channel */
 564 static void process_event(JSONMessageParser *parser, QList *tokens)
 565 {
 566     GAState *s = container_of(parser, GAState, parser);
 567     QObject *obj;
 568     QDict *qdict;
 569     Error *err = NULL;
 570     int ret;
 571
 572     g_assert(s && parser);
 573
 574     g_debug("process_event: called");
 575     obj = json_parser_parse_err(tokens, NULL, &err);
 576     if (err || !obj || qobject_type(obj) != QTYPE_QDICT) {
 577         qobject_decref(obj);
 578         qdict = qdict_new();
 579         if (!err) {
 580             g_warning("failed to parse event: unknown error");
 581             error_set(&err, QERR_JSON_PARSING);
 582         } else {
 583             g_warning("failed to parse event: %s", error_get_pretty(err));
 584         }
 585         qdict_put_obj(qdict, "error", qmp_build_error_object(err));
 586         error_free(err);
 587     } else {
 588         qdict = qobject_to_qdict(obj);
 589     }
 590
 591     g_assert(qdict);
 592
 593     /* handle host->guest commands */
 594     if (qdict_haskey(qdict, "execute")) {
 595         process_command(s, qdict);
 596     } else {
 597         if (!qdict_haskey(qdict, "error")) {
 598             QDECREF(qdict);
 599             qdict = qdict_new();
 600             g_warning("unrecognized payload format");
 601             error_set(&err, QERR_UNSUPPORTED);
 602             qdict_put_obj(qdict, "error", qmp_build_error_object(err));
 603             error_free(err);
 604         }
 605         ret = send_response(s, QOBJECT(qdict));
 606         if (ret < 0) {
 607             g_warning("error sending error response: %s", strerror(-ret));
 608         }
 609     }
 610
 611     QDECREF(qdict);
 612 }
 613
 614 /* false return signals GAChannel to close the current client connection */
 615 static gboolean channel_event_cb(GIOCondition condition, gpointer data)
 616 {
 617     GAState *s = data;
 618     gchar buf[QGA_READ_COUNT_DEFAULT+1];
 619     gsize count;
 620     GError *err = NULL;
 621     GIOStatus status = ga_channel_read(s->channel, buf, QGA_READ_COUNT_DEFAULT, &count);
 622     if (err != NULL) {
 623         g_warning("error reading channel: %s", err->message);
 624         g_error_free(err);
 625         return false;
 626     }
 627     switch (status) {
 628     case G_IO_STATUS_ERROR:
 629         g_warning("error reading channel");
 630         return false;
 631     case G_IO_STATUS_NORMAL:
 632         buf[count] = 0;
 633         g_debug("read data, count: %d, data: %s", (int)count, buf);
 634         json_message_parser_feed(&s->parser, (char *)buf, (int)count);
 635         break;
 636     case G_IO_STATUS_EOF:
 637         g_debug("received EOF");
 638         if (!s->virtio) {
 639             return false;
 640         }
 641         /* fall through */
 642     case G_IO_STATUS_AGAIN:
 643         /* virtio causes us to spin here when no process is attached to
 644          * host-side chardev. sleep a bit to mitigate this
 645          */
 646         if (s->virtio) {
 647             usleep(100*1000);
 648         }
 649         return true;
 650     default:
 651         g_warning("unknown channel read status, closing");
 652         return false;
 653     }
 654     return true;
 655 }
 656
 657 static gboolean channel_init(GAState *s, const gchar *method, const gchar *path)
 658 {
 659     GAChannelMethod channel_method;
 660
 661     if (method == NULL) {
 662         method = "virtio-serial";
 663     }
 664
 665     if (path == NULL) {
 666         if (strcmp(method, "virtio-serial") == 0 ) {
 667             /* try the default path for the virtio-serial port */
 668             path = QGA_VIRTIO_PATH_DEFAULT;
 669         } else if (strcmp(method, "isa-serial") == 0){
 670             /* try the default path for the serial port - COM1 */
 671             path = QGA_SERIAL_PATH_DEFAULT;
 672         } else {
 673             g_critical("must specify a path for this channel");
 674             return false;
 675         }
 676     }
 677
 678     if (strcmp(method, "virtio-serial") == 0) {
 679         s->virtio = true; /* virtio requires special handling in some cases */
 680         channel_method = GA_CHANNEL_VIRTIO_SERIAL;
 681     } else if (strcmp(method, "isa-serial") == 0) {
 682         channel_method = GA_CHANNEL_ISA_SERIAL;
 683     } else if (strcmp(method, "unix-listen") == 0) {
 684         channel_method = GA_CHANNEL_UNIX_LISTEN;
 685     } else {
 686         g_critical("unsupported channel method/type: %s", method);
 687         return false;
 688     }
 689
 690     s->channel = ga_channel_new(channel_method, path, channel_event_cb, s);
 691     if (!s->channel) {
 692         g_critical("failed to create guest agent channel");
 693         return false;
 694     }
 695
 696     return true;
 697 }
 698
 699 #ifdef _WIN32
 700 DWORD WINAPI service_ctrl_handler(DWORD ctrl, DWORD type, LPVOID data,
 701                                   LPVOID ctx)
 702 {
 703     DWORD ret = NO_ERROR;
 704     GAService *service = &ga_state->service;
 705
 706     switch (ctrl)
 707     {
 708         case SERVICE_CONTROL_STOP:
 709         case SERVICE_CONTROL_SHUTDOWN:
 710             quit_handler(SIGTERM);
 711             service->status.dwCurrentState = SERVICE_STOP_PENDING;
 712             SetServiceStatus(service->status_handle, &service->status);
 713             break;
 714
 715         default:
 716             ret = ERROR_CALL_NOT_IMPLEMENTED;
 717     }
 718     return ret;
 719 }
 720
 721 VOID WINAPI service_main(DWORD argc, TCHAR *argv[])
 722 {
 723     GAService *service = &ga_state->service;
 724
 725     service->status_handle = RegisterServiceCtrlHandlerEx(QGA_SERVICE_NAME,
 726         service_ctrl_handler, NULL);
 727
 728     if (service->status_handle == 0) {
 729         g_critical("Failed to register extended requests function!\n");
 730         return;
 731     }
 732
 733     service->status.dwServiceType = SERVICE_WIN32;
 734     service->status.dwCurrentState = SERVICE_RUNNING;
 735     service->status.dwControlsAccepted = SERVICE_ACCEPT_STOP | SERVICE_ACCEPT_SHUTDOWN;
 736     service->status.dwWin32ExitCode = NO_ERROR;
 737     service->status.dwServiceSpecificExitCode = NO_ERROR;
 738     service->status.dwCheckPoint = 0;
 739     service->status.dwWaitHint = 0;
 740     SetServiceStatus(service->status_handle, &service->status);
 741
 742     g_main_loop_run(ga_state->main_loop);
 743
 744     service->status.dwCurrentState = SERVICE_STOPPED;
 745     SetServiceStatus(service->status_handle, &service->status);
 746 }
 747 #endif
 748
 749 static void set_persistent_state_defaults(GAPersistentState *pstate)
 750 {
 751     g_assert(pstate);
 752     pstate->fd_counter = QGA_PSTATE_DEFAULT_FD_COUNTER;
 753 }
 754
 755 static void persistent_state_from_keyfile(GAPersistentState *pstate,
 756                                           GKeyFile *keyfile)
 757 {
 758     g_assert(pstate);
 759     g_assert(keyfile);
 760     /* if any fields are missing, either because the file was tampered with
 761      * by agents of chaos, or because the field wasn't present at the time the
 762      * file was created, the best we can ever do is start over with the default
 763      * values. so load them now, and ignore any errors in accessing key-value
 764      * pairs
 765      */
 766     set_persistent_state_defaults(pstate);
 767
 768     if (g_key_file_has_key(keyfile, "global", "fd_counter", NULL)) {
 769         pstate->fd_counter =
 770             g_key_file_get_integer(keyfile, "global", "fd_counter", NULL);
 771     }
 772 }
 773
 774 static void persistent_state_to_keyfile(const GAPersistentState *pstate,
 775                                         GKeyFile *keyfile)
 776 {
 777     g_assert(pstate);
 778     g_assert(keyfile);
 779
 780     g_key_file_set_integer(keyfile, "global", "fd_counter", pstate->fd_counter);
 781 }
 782
 783 static gboolean write_persistent_state(const GAPersistentState *pstate,
 784                                        const gchar *path)
 785 {
 786     GKeyFile *keyfile = g_key_file_new();
 787     GError *gerr = NULL;
 788     gboolean ret = true;
 789     gchar *data = NULL;
 790     gsize data_len;
 791
 792     g_assert(pstate);
 793
 794     persistent_state_to_keyfile(pstate, keyfile);
 795     data = g_key_file_to_data(keyfile, &data_len, &gerr);
 796     if (gerr) {
 797         g_critical("failed to convert persistent state to string: %s",
 798                    gerr->message);
 799         ret = false;
 800         goto out;
 801     }
 802
 803     g_file_set_contents(path, data, data_len, &gerr);
 804     if (gerr) {
 805         g_critical("failed to write persistent state to %s: %s",
 806                     path, gerr->message);
 807         ret = false;
 808         goto out;
 809     }
 810
 811 out:
 812     if (gerr) {
 813         g_error_free(gerr);
 814     }
 815     if (keyfile) {
 816         g_key_file_free(keyfile);
 817     }
 818     g_free(data);
 819     return ret;
 820 }
 821
 822 static gboolean read_persistent_state(GAPersistentState *pstate,
 823                                       const gchar *path, gboolean frozen)
 824 {
 825     GKeyFile *keyfile = NULL;
 826     GError *gerr = NULL;
 827     struct stat st;
 828     gboolean ret = true;
 829
 830     g_assert(pstate);
 831
 832     if (stat(path, &st) == -1) {
 833         /* it's okay if state file doesn't exist, but any other error
 834          * indicates a permissions issue or some other misconfiguration
 835          * that we likely won't be able to recover from.
 836          */
 837         if (errno != ENOENT) {
 838             g_critical("unable to access state file at path %s: %s",
 839                        path, strerror(errno));
 840             ret = false;
 841             goto out;
 842         }
 843
 844         /* file doesn't exist. initialize state to default values and
 845          * attempt to save now. (we could wait till later when we have
 846          * modified state we need to commit, but if there's a problem,
 847          * such as a missing parent directory, we want to catch it now)
 848          *
 849          * there is a potential scenario where someone either managed to
 850          * update the agent from a version that didn't use a key store
 851          * while qemu-ga thought the filesystem was frozen, or
 852          * deleted the key store prior to issuing a fsfreeze, prior
 853          * to restarting the agent. in this case we go ahead and defer
 854          * initial creation till we actually have modified state to
 855          * write, otherwise fail to recover from freeze.
 856          */
 857         set_persistent_state_defaults(pstate);
 858         if (!frozen) {
 859             ret = write_persistent_state(pstate, path);
 860             if (!ret) {
 861                 g_critical("unable to create state file at path %s", path);
 862                 ret = false;
 863                 goto out;
 864             }
 865         }
 866         ret = true;
 867         goto out;
 868     }
 869
 870     keyfile = g_key_file_new();
 871     g_key_file_load_from_file(keyfile, path, 0, &gerr);
 872     if (gerr) {
 873         g_critical("error loading persistent state from path: %s, %s",
 874                    path, gerr->message);
 875         ret = false;
 876         goto out;
 877     }
 878
 879     persistent_state_from_keyfile(pstate, keyfile);
 880
 881 out:
 882     if (keyfile) {
 883         g_key_file_free(keyfile);
 884     }
 885     if (gerr) {
 886         g_error_free(gerr);
 887     }
 888
 889     return ret;
 890 }
 891
 892 int64_t ga_get_fd_handle(GAState *s, Error **errp)
 893 {
 894     int64_t handle;
 895
 896     g_assert(s->pstate_filepath);
 897     /* we blacklist commands and avoid operations that potentially require
 898      * writing to disk when we're in a frozen state. this includes opening
 899      * new files, so we should never get here in that situation
 900      */
 901     g_assert(!ga_is_frozen(s));
 902
 903     handle = s->pstate.fd_counter++;
 904
 905     /* This should never happen on a reasonable timeframe, as guest-file-open
 906      * would have to be issued 2^63 times */
 907     if (s->pstate.fd_counter == INT64_MAX) {
 908         abort();
 909     }
 910
 911     if (!write_persistent_state(&s->pstate, s->pstate_filepath)) {
 912         error_setg(errp, "failed to commit persistent state to disk");
 913         return -1;
 914     }
 915
 916     return handle;
 917 }
 918
 919 static void ga_print_cmd(QmpCommand *cmd, void *opaque)
 920 {
 921     printf("%s\n", qmp_command_name(cmd));
 922 }
 923
 924 int main(int argc, char **argv)
 925 {
 926     const char *sopt = "hVvdm:p:l:f:F::b:s:t:";
 927     const char *method = NULL, *path = NULL;
 928     const char *log_filepath = NULL;
 929     const char *pid_filepath;
 930 #ifdef CONFIG_FSFREEZE
 931     const char *fsfreeze_hook = NULL;
 932 #endif
 933     const char *state_dir;
 934 #ifdef _WIN32
 935     const char *service = NULL;
 936 #endif
 937     const struct option lopt[] = {
 938         { "help", 0, NULL, 'h' },
 939         { "version", 0, NULL, 'V' },
 940         { "logfile", 1, NULL, 'l' },
 941         { "pidfile", 1, NULL, 'f' },
 942 #ifdef CONFIG_FSFREEZE
 943         { "fsfreeze-hook", 2, NULL, 'F' },
 944 #endif
 945         { "verbose", 0, NULL, 'v' },
 946         { "method", 1, NULL, 'm' },
 947         { "path", 1, NULL, 'p' },
 948         { "daemonize", 0, NULL, 'd' },
 949         { "blacklist", 1, NULL, 'b' },
 950 #ifdef _WIN32
 951         { "service", 1, NULL, 's' },
 952 #endif
 953         { "statedir", 1, NULL, 't' },
 954         { NULL, 0, NULL, 0 }
 955     };
 956     int opt_ind = 0, ch, daemonize = 0, i, j, len;
 957     GLogLevelFlags log_level = G_LOG_LEVEL_ERROR | G_LOG_LEVEL_CRITICAL;
 958     GList *blacklist = NULL;
 959     GAState *s;
 960
 961     module_call_init(MODULE_INIT_QAPI);
 962
 963     init_dfl_pathnames();
 964     pid_filepath = dfl_pathnames.pidfile;
 965     state_dir = dfl_pathnames.state_dir;
 966
 967     while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
 968         switch (ch) {
 969         case 'm':
 970             method = optarg;
 971             break;
 972         case 'p':
 973             path = optarg;
 974             break;
 975         case 'l':
 976             log_filepath = optarg;
 977             break;
 978         case 'f':
 979             pid_filepath = optarg;
 980             break;
 981 #ifdef CONFIG_FSFREEZE
 982         case 'F':
 983             fsfreeze_hook = optarg ? optarg : QGA_FSFREEZE_HOOK_DEFAULT;
 984             break;
 985 #endif
 986         case 't':
 987              state_dir = optarg;
 988              break;
 989         case 'v':
 990             /* enable all log levels */
 991             log_level = G_LOG_LEVEL_MASK;
 992             break;
 993         case 'V':
 994             printf("QEMU Guest Agent %s\n", QEMU_VERSION);
 995             return 0;
 996         case 'd':
 997             daemonize = 1;
 998             break;
 999         case 'b': {
1000             if (is_help_option(optarg)) {
1001                 qmp_for_each_command(ga_print_cmd, NULL);
1002                 return 0;
1003             }
1004             for (j = 0, i = 0, len = strlen(optarg); i < len; i++) {
1005                 if (optarg[i] == ',') {
1006                     optarg[i] = 0;
1007                     blacklist = g_list_append(blacklist, &optarg[j]);
1008                     j = i + 1;
1009                 }
1010             }
1011             if (j < i) {
1012                 blacklist = g_list_append(blacklist, &optarg[j]);
1013             }
1014             break;
1015         }
1016 #ifdef _WIN32
1017         case 's':
1018             service = optarg;
1019             if (strcmp(service, "install") == 0) {
1020                 const char *fixed_state_dir;
1021
1022                 /* If the user passed the "-t" option, we save that state dir
1023                  * in the service. Otherwise we let the service fetch the state
1024                  * dir from the environment when it starts.
1025                  */
1026                 fixed_state_dir = (state_dir == dfl_pathnames.state_dir) ?
1027                                   NULL :
1028                                   state_dir;
1029                 if (ga_install_vss_provider()) {
1030                     return EXIT_FAILURE;
1031                 }
1032                 if (ga_install_service(path, log_filepath, fixed_state_dir)) {
1033                     return EXIT_FAILURE;
1034                 }
1035                 return 0;
1036             } else if (strcmp(service, "uninstall") == 0) {
1037                 ga_uninstall_vss_provider();
1038                 return ga_uninstall_service();
1039             } else {
1040                 printf("Unknown service command.\n");
1041                 return EXIT_FAILURE;
1042             }
1043             break;
1044 #endif
1045         case 'h':
1046             usage(argv[0]);
1047             return 0;
1048         case '?':
1049             g_print("Unknown option, try '%s --help' for more information.\n",
1050                     argv[0]);
1051             return EXIT_FAILURE;
1052         }
1053     }
1054
1055 #ifdef _WIN32
1056     /* On win32 the state directory is application specific (be it the default
1057      * or a user override). We got past the command line parsing; let's create
1058      * the directory (with any intermediate directories). If we run into an
1059      * error later on, we won't try to clean up the directory, it is considered
1060      * persistent.
1061      */
1062     if (g_mkdir_with_parents(state_dir, S_IRWXU) == -1) {
1063         g_critical("unable to create (an ancestor of) the state directory"
1064                    " '%s': %s", state_dir, strerror(errno));
1065         return EXIT_FAILURE;
1066     }
1067 #endif
1068
1069     s = g_malloc0(sizeof(GAState));
1070     s->log_level = log_level;
1071     s->log_file = stderr;
1072 #ifdef CONFIG_FSFREEZE
1073     s->fsfreeze_hook = fsfreeze_hook;
1074 #endif
1075     g_log_set_default_handler(ga_log, s);
1076     g_log_set_fatal_mask(NULL, G_LOG_LEVEL_ERROR);
1077     ga_enable_logging(s);
1078     s->state_filepath_isfrozen = g_strdup_printf("%s/qga.state.isfrozen",
1079                                                  state_dir);
1080     s->pstate_filepath = g_strdup_printf("%s/qga.state", state_dir);
1081     s->frozen = false;
1082
1083 #ifndef _WIN32
1084     /* check if a previous instance of qemu-ga exited with filesystems' state
1085      * marked as frozen. this could be a stale value (a non-qemu-ga process
1086      * or reboot may have since unfrozen them), but better to require an
1087      * uneeded unfreeze than to risk hanging on start-up
1088      */
1089     struct stat st;
1090     if (stat(s->state_filepath_isfrozen, &st) == -1) {
1091         /* it's okay if the file doesn't exist, but if we can't access for
1092          * some other reason, such as permissions, there's a configuration
1093          * that needs to be addressed. so just bail now before we get into
1094          * more trouble later
1095          */
1096         if (errno != ENOENT) {
1097             g_critical("unable to access state file at path %s: %s",
1098                        s->state_filepath_isfrozen, strerror(errno));
1099             return EXIT_FAILURE;
1100         }
1101     } else {
1102         g_warning("previous instance appears to have exited with frozen"
1103                   " filesystems. deferring logging/pidfile creation and"
1104                   " disabling non-fsfreeze-safe commands until"
1105                   " guest-fsfreeze-thaw is issued, or filesystems are"
1106                   " manually unfrozen and the file %s is removed",
1107                   s->state_filepath_isfrozen);
1108         s->frozen = true;
1109     }
1110 #endif
1111
1112     if (ga_is_frozen(s)) {
1113         if (daemonize) {
1114             /* delay opening/locking of pidfile till filesystems are unfrozen */
1115             s->deferred_options.pid_filepath = pid_filepath;
1116             become_daemon(NULL);
1117         }
1118         if (log_filepath) {
1119             /* delay opening the log file till filesystems are unfrozen */
1120             s->deferred_options.log_filepath = log_filepath;
1121         }
1122         ga_disable_logging(s);
1123         qmp_for_each_command(ga_disable_non_whitelisted, NULL);
1124     } else {
1125         if (daemonize) {
1126             become_daemon(pid_filepath);
1127         }
1128         if (log_filepath) {
1129             FILE *log_file = ga_open_logfile(log_filepath);
1130             if (!log_file) {
1131                 g_critical("unable to open specified log file: %s",
1132                            strerror(errno));
1133                 goto out_bad;
1134             }
1135             s->log_file = log_file;
1136         }
1137     }
1138
1139     /* load persistent state from disk */
1140     if (!read_persistent_state(&s->pstate,
1141                                s->pstate_filepath,
1142                                ga_is_frozen(s))) {
1143         g_critical("failed to load persistent state");
1144         goto out_bad;
1145     }
1146
1147     blacklist = ga_command_blacklist_init(blacklist);
1148     if (blacklist) {
1149         s->blacklist = blacklist;
1150         do {
1151             g_debug("disabling command: %s", (char *)blacklist->data);
1152             qmp_disable_command(blacklist->data);
1153             blacklist = g_list_next(blacklist);
1154         } while (blacklist);
1155     }
1156     s->command_state = ga_command_state_new();
1157     ga_command_state_init(s, s->command_state);
1158     ga_command_state_init_all(s->command_state);
1159     json_message_parser_init(&s->parser, process_event);
1160     ga_state = s;
1161 #ifndef _WIN32
1162     if (!register_signal_handlers()) {
1163         g_critical("failed to register signal handlers");
1164         goto out_bad;
1165     }
1166 #endif
1167
1168     s->main_loop = g_main_loop_new(NULL, false);
1169     if (!channel_init(ga_state, method, path)) {
1170         g_critical("failed to initialize guest agent channel");
1171         goto out_bad;
1172     }
1173 #ifndef _WIN32
1174     g_main_loop_run(ga_state->main_loop);
1175 #else
1176     if (daemonize) {
1177         SERVICE_TABLE_ENTRY service_table[] = {
1178             { (char *)QGA_SERVICE_NAME, service_main }, { NULL, NULL } };
1179         StartServiceCtrlDispatcher(service_table);
1180     } else {
1181         g_main_loop_run(ga_state->main_loop);
1182     }
1183 #endif
1184
1185     ga_command_state_cleanup_all(ga_state->command_state);
1186     ga_channel_free(ga_state->channel);
1187
1188     if (daemonize) {
1189         unlink(pid_filepath);
1190     }
1191     return 0;
1192
1193 out_bad:
1194     if (daemonize) {
1195         unlink(pid_filepath);
1196     }
1197     return EXIT_FAILURE;
1198 }