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 #include <windows.h>
  39 #endif
  40 #ifdef __linux__
  41 #include <linux/fs.h>
  42 #ifdef FIFREEZE
  43 #define CONFIG_FSFREEZE
  44 #endif
  45 #endif
  46
  47 #ifndef _WIN32
  48 #define QGA_VIRTIO_PATH_DEFAULT "/dev/virtio-ports/org.qemu.guest_agent.0"
  49 #define QGA_STATE_RELATIVE_DIR  "run"
  50 #else
  51 #define QGA_VIRTIO_PATH_DEFAULT "\\\\.\\Global\\org.qemu.guest_agent.0"
  52 #define QGA_STATE_RELATIVE_DIR  "qemu-ga"
  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
  59 static struct {
  60     const char *state_dir;
  61     const char *pidfile;
  62 } dfl_pathnames;
  63
  64 typedef struct GAPersistentState {
  65 #define QGA_PSTATE_DEFAULT_FD_COUNTER 1000
  66     int64_t fd_counter;
  67 } GAPersistentState;
  68
  69 struct GAState {
  70     JSONMessageParser parser;
  71     GMainLoop *main_loop;
  72     GAChannel *channel;
  73     bool virtio; /* fastpath to check for virtio to deal with poll() quirks */
  74     GACommandState *command_state;
  75     GLogLevelFlags log_level;
  76     FILE *log_file;
  77     bool logging_enabled;
  78 #ifdef _WIN32
  79     GAService service;
  80 #endif
  81     bool delimit_response;
  82     bool frozen;
  83     GList *blacklist;
  84     const char *state_filepath_isfrozen;
  85     struct {
  86         const char *log_filepath;
  87         const char *pid_filepath;
  88     } deferred_options;
  89 #ifdef CONFIG_FSFREEZE
  90     const char *fsfreeze_hook;
  91 #endif
  92     const gchar *pstate_filepath;
  93     GAPersistentState pstate;
  94 };
  95
  96 struct GAState *ga_state;
  97
  98 /* commands that are safe to issue while filesystems are frozen */
  99 static const char *ga_freeze_whitelist[] = {
 100     "guest-ping",
 101     "guest-info",
 102     "guest-sync",
 103     "guest-sync-delimited",
 104     "guest-fsfreeze-status",
 105     "guest-fsfreeze-thaw",
 106     NULL
 107 };
 108
 109 #ifdef _WIN32
 110 DWORD WINAPI service_ctrl_handler(DWORD ctrl, DWORD type, LPVOID data,
 111                                   LPVOID ctx);
 112 VOID WINAPI service_main(DWORD argc, TCHAR *argv[]);
 113 #endif
 114
 115 static void
 116 init_dfl_pathnames(void)
 117 {
 118     g_assert(dfl_pathnames.state_dir == NULL);
 119     g_assert(dfl_pathnames.pidfile == NULL);
 120     dfl_pathnames.state_dir = qemu_get_local_state_pathname(
 121       QGA_STATE_RELATIVE_DIR);
 122     dfl_pathnames.pidfile   = qemu_get_local_state_pathname(
 123       QGA_STATE_RELATIVE_DIR G_DIR_SEPARATOR_S "qemu-ga.pid");
 124 }
 125
 126 static void quit_handler(int sig)
 127 {
 128     /* if we're frozen, don't exit unless we're absolutely forced to,
 129      * because it's basically impossible for graceful exit to complete
 130      * unless all log/pid files are on unfreezable filesystems. there's
 131      * also a very likely chance killing the agent before unfreezing
 132      * the filesystems is a mistake (or will be viewed as one later).
 133      */
 134     if (ga_is_frozen(ga_state)) {
 135         return;
 136     }
 137     g_debug("received signal num %d, quitting", sig);
 138
 139     if (g_main_loop_is_running(ga_state->main_loop)) {
 140         g_main_loop_quit(ga_state->main_loop);
 141     }
 142 }
 143
 144 #ifndef _WIN32
 145 static gboolean register_signal_handlers(void)
 146 {
 147     struct sigaction sigact;
 148     int ret;
 149
 150     memset(&sigact, 0, sizeof(struct sigaction));
 151     sigact.sa_handler = quit_handler;
 152
 153     ret = sigaction(SIGINT, &sigact, NULL);
 154     if (ret == -1) {
 155         g_error("error configuring signal handler: %s", strerror(errno));
 156     }
 157     ret = sigaction(SIGTERM, &sigact, NULL);
 158     if (ret == -1) {
 159         g_error("error configuring signal handler: %s", strerror(errno));
 160     }
 161
 162     return true;
 163 }
 164
 165 /* TODO: use this in place of all post-fork() fclose(std*) callers */
 166 void reopen_fd_to_null(int fd)
 167 {
 168     int nullfd;
 169
 170     nullfd = open("/dev/null", O_RDWR);
 171     if (nullfd < 0) {
 172         return;
 173     }
 174
 175     dup2(nullfd, fd);
 176
 177     if (nullfd != fd) {
 178         close(nullfd);
 179     }
 180 }
 181 #endif
 182
 183 static void usage(const char *cmd)
 184 {
 185     printf(
 186 "Usage: %s [-m <method> -p <path>] [<options>]\n"
 187 "QEMU Guest Agent %s\n"
 188 "\n"
 189 "  -m, --method      transport method: one of unix-listen, virtio-serial, or\n"
 190 "                    isa-serial (virtio-serial is the default)\n"
 191 "  -p, --path        device/socket path (the default for virtio-serial is:\n"
 192 "                    %s)\n"
 193 "  -l, --logfile     set logfile path, logs to stderr by default\n"
 194 "  -f, --pidfile     specify pidfile (default is %s)\n"
 195 #ifdef CONFIG_FSFREEZE
 196 "  -F, --fsfreeze-hook\n"
 197 "                    enable fsfreeze hook. Accepts an optional argument that\n"
 198 "                    specifies script to run on freeze/thaw. Script will be\n"
 199 "                    called with 'freeze'/'thaw' arguments accordingly.\n"
 200 "                    (default is %s)\n"
 201 "                    If using -F with an argument, do not follow -F with a\n"
 202 "                    space.\n"
 203 "                    (for example: -F/var/run/fsfreezehook.sh)\n"
 204 #endif
 205 "  -t, --statedir    specify dir to store state information (absolute paths\n"
 206 "                    only, default is %s)\n"
 207 "  -v, --verbose     log extra debugging information\n"
 208 "  -V, --version     print version information and exit\n"
 209 "  -d, --daemonize   become a daemon\n"
 210 #ifdef _WIN32
 211 "  -s, --service     service commands: install, uninstall\n"
 212 #endif
 213 "  -b, --blacklist   comma-separated list of RPCs to disable (no spaces, \"?\"\n"
 214 "                    to list available RPCs)\n"
 215 "  -h, --help        display this help and exit\n"
 216 "\n"
 217 "Report bugs to <mdroth@linux.vnet.ibm.com>\n"
 218     , cmd, QEMU_VERSION, QGA_VIRTIO_PATH_DEFAULT, dfl_pathnames.pidfile,
 219 #ifdef CONFIG_FSFREEZE
 220     QGA_FSFREEZE_HOOK_DEFAULT,
 221 #endif
 222     dfl_pathnames.state_dir);
 223 }
 224
 225 static const char *ga_log_level_str(GLogLevelFlags level)
 226 {
 227     switch (level & G_LOG_LEVEL_MASK) {
 228         case G_LOG_LEVEL_ERROR:
 229             return "error";
 230         case G_LOG_LEVEL_CRITICAL:
 231             return "critical";
 232         case G_LOG_LEVEL_WARNING:
 233             return "warning";
 234         case G_LOG_LEVEL_MESSAGE:
 235             return "message";
 236         case G_LOG_LEVEL_INFO:
 237             return "info";
 238         case G_LOG_LEVEL_DEBUG:
 239             return "debug";
 240         default:
 241             return "user";
 242     }
 243 }
 244
 245 bool ga_logging_enabled(GAState *s)
 246 {
 247     return s->logging_enabled;
 248 }
 249
 250 void ga_disable_logging(GAState *s)
 251 {
 252     s->logging_enabled = false;
 253 }
 254
 255 void ga_enable_logging(GAState *s)
 256 {
 257     s->logging_enabled = true;
 258 }
 259
 260 static void ga_log(const gchar *domain, GLogLevelFlags level,
 261                    const gchar *msg, gpointer opaque)
 262 {
 263     GAState *s = opaque;
 264     GTimeVal time;
 265     const char *level_str = ga_log_level_str(level);
 266
 267     if (!ga_logging_enabled(s)) {
 268         return;
 269     }
 270
 271     level &= G_LOG_LEVEL_MASK;
 272 #ifndef _WIN32
 273     if (domain && strcmp(domain, "syslog") == 0) {
 274         syslog(LOG_INFO, "%s: %s", level_str, msg);
 275     } else if (level & s->log_level) {
 276 #else
 277     if (level & s->log_level) {
 278 #endif
 279         g_get_current_time(&time);
 280         fprintf(s->log_file,
 281                 "%lu.%lu: %s: %s\n", time.tv_sec, time.tv_usec, level_str, msg);
 282         fflush(s->log_file);
 283     }
 284 }
 285
 286 void ga_set_response_delimited(GAState *s)
 287 {
 288     s->delimit_response = true;
 289 }
 290
 291 static FILE *ga_open_logfile(const char *logfile)
 292 {
 293     FILE *f;
 294
 295     f = fopen(logfile, "a");
 296     if (!f) {
 297         return NULL;
 298     }
 299
 300     qemu_set_cloexec(fileno(f));
 301     return f;
 302 }
 303
 304 #ifndef _WIN32
 305 static bool ga_open_pidfile(const char *pidfile)
 306 {
 307     int pidfd;
 308     char pidstr[32];
 309
 310     pidfd = qemu_open(pidfile, O_CREAT|O_WRONLY, S_IRUSR|S_IWUSR);
 311     if (pidfd == -1 || lockf(pidfd, F_TLOCK, 0)) {
 312         g_critical("Cannot lock pid file, %s", strerror(errno));
 313         if (pidfd != -1) {
 314             close(pidfd);
 315         }
 316         return false;
 317     }
 318
 319     if (ftruncate(pidfd, 0)) {
 320         g_critical("Failed to truncate pid file");
 321         goto fail;
 322     }
 323     snprintf(pidstr, sizeof(pidstr), "%d\n", getpid());
 324     if (write(pidfd, pidstr, strlen(pidstr)) != strlen(pidstr)) {
 325         g_critical("Failed to write pid file");
 326         goto fail;
 327     }
 328
 329     /* keep pidfile open & locked forever */
 330     return true;
 331
 332 fail:
 333     unlink(pidfile);
 334     close(pidfd);
 335     return false;
 336 }
 337 #else /* _WIN32 */
 338 static bool ga_open_pidfile(const char *pidfile)
 339 {
 340     return true;
 341 }
 342 #endif
 343
 344 static gint ga_strcmp(gconstpointer str1, gconstpointer str2)
 345 {
 346     return strcmp(str1, str2);
 347 }
 348
 349 /* disable commands that aren't safe for fsfreeze */
 350 static void ga_disable_non_whitelisted(void)
 351 {
 352     char **list_head, **list;
 353     bool whitelisted;
 354     int i;
 355
 356     list_head = list = qmp_get_command_list();
 357     while (*list != NULL) {
 358         whitelisted = false;
 359         i = 0;
 360         while (ga_freeze_whitelist[i] != NULL) {
 361             if (strcmp(*list, ga_freeze_whitelist[i]) == 0) {
 362                 whitelisted = true;
 363             }
 364             i++;
 365         }
 366         if (!whitelisted) {
 367             g_debug("disabling command: %s", *list);
 368             qmp_disable_command(*list);
 369         }
 370         g_free(*list);
 371         list++;
 372     }
 373     g_free(list_head);
 374 }
 375
 376 /* [re-]enable all commands, except those explicitly blacklisted by user */
 377 static void ga_enable_non_blacklisted(GList *blacklist)
 378 {
 379     char **list_head, **list;
 380
 381     list_head = list = qmp_get_command_list();
 382     while (*list != NULL) {
 383         if (g_list_find_custom(blacklist, *list, ga_strcmp) == NULL &&
 384             !qmp_command_is_enabled(*list)) {
 385             g_debug("enabling command: %s", *list);
 386             qmp_enable_command(*list);
 387         }
 388         g_free(*list);
 389         list++;
 390     }
 391     g_free(list_head);
 392 }
 393
 394 static bool ga_create_file(const char *path)
 395 {
 396     int fd = open(path, O_CREAT | O_WRONLY, S_IWUSR | S_IRUSR);
 397     if (fd == -1) {
 398         g_warning("unable to open/create file %s: %s", path, strerror(errno));
 399         return false;
 400     }
 401     close(fd);
 402     return true;
 403 }
 404
 405 static bool ga_delete_file(const char *path)
 406 {
 407     int ret = unlink(path);
 408     if (ret == -1) {
 409         g_warning("unable to delete file: %s: %s", path, strerror(errno));
 410         return false;
 411     }
 412
 413     return true;
 414 }
 415
 416 bool ga_is_frozen(GAState *s)
 417 {
 418     return s->frozen;
 419 }
 420
 421 void ga_set_frozen(GAState *s)
 422 {
 423     if (ga_is_frozen(s)) {
 424         return;
 425     }
 426     /* disable all non-whitelisted (for frozen state) commands */
 427     ga_disable_non_whitelisted();
 428     g_warning("disabling logging due to filesystem freeze");
 429     ga_disable_logging(s);
 430     s->frozen = true;
 431     if (!ga_create_file(s->state_filepath_isfrozen)) {
 432         g_warning("unable to create %s, fsfreeze may not function properly",
 433                   s->state_filepath_isfrozen);
 434     }
 435 }
 436
 437 void ga_unset_frozen(GAState *s)
 438 {
 439     if (!ga_is_frozen(s)) {
 440         return;
 441     }
 442
 443     /* if we delayed creation/opening of pid/log files due to being
 444      * in a frozen state at start up, do it now
 445      */
 446     if (s->deferred_options.log_filepath) {
 447         s->log_file = ga_open_logfile(s->deferred_options.log_filepath);
 448         if (!s->log_file) {
 449             s->log_file = stderr;
 450         }
 451         s->deferred_options.log_filepath = NULL;
 452     }
 453     ga_enable_logging(s);
 454     g_warning("logging re-enabled due to filesystem unfreeze");
 455     if (s->deferred_options.pid_filepath) {
 456         if (!ga_open_pidfile(s->deferred_options.pid_filepath)) {
 457             g_warning("failed to create/open pid file");
 458         }
 459         s->deferred_options.pid_filepath = NULL;
 460     }
 461
 462     /* enable all disabled, non-blacklisted commands */
 463     ga_enable_non_blacklisted(s->blacklist);
 464     s->frozen = false;
 465     if (!ga_delete_file(s->state_filepath_isfrozen)) {
 466         g_warning("unable to delete %s, fsfreeze may not function properly",
 467                   s->state_filepath_isfrozen);
 468     }
 469 }
 470
 471 #ifdef CONFIG_FSFREEZE
 472 const char *ga_fsfreeze_hook(GAState *s)
 473 {
 474     return s->fsfreeze_hook;
 475 }
 476 #endif
 477
 478 static void become_daemon(const char *pidfile)
 479 {
 480 #ifndef _WIN32
 481     pid_t pid, sid;
 482
 483     pid = fork();
 484     if (pid < 0) {
 485         exit(EXIT_FAILURE);
 486     }
 487     if (pid > 0) {
 488         exit(EXIT_SUCCESS);
 489     }
 490
 491     if (pidfile) {
 492         if (!ga_open_pidfile(pidfile)) {
 493             g_critical("failed to create pidfile");
 494             exit(EXIT_FAILURE);
 495         }
 496     }
 497
 498     umask(S_IRWXG | S_IRWXO);
 499     sid = setsid();
 500     if (sid < 0) {
 501         goto fail;
 502     }
 503     if ((chdir("/")) < 0) {
 504         goto fail;
 505     }
 506
 507     reopen_fd_to_null(STDIN_FILENO);
 508     reopen_fd_to_null(STDOUT_FILENO);
 509     reopen_fd_to_null(STDERR_FILENO);
 510     return;
 511
 512 fail:
 513     if (pidfile) {
 514         unlink(pidfile);
 515     }
 516     g_critical("failed to daemonize");
 517     exit(EXIT_FAILURE);
 518 #endif
 519 }
 520
 521 static int send_response(GAState *s, QObject *payload)
 522 {
 523     const char *buf;
 524     QString *payload_qstr, *response_qstr;
 525     GIOStatus status;
 526
 527     g_assert(payload && s->channel);
 528
 529     payload_qstr = qobject_to_json(payload);
 530     if (!payload_qstr) {
 531         return -EINVAL;
 532     }
 533
 534     if (s->delimit_response) {
 535         s->delimit_response = false;
 536         response_qstr = qstring_new();
 537         qstring_append_chr(response_qstr, QGA_SENTINEL_BYTE);
 538         qstring_append(response_qstr, qstring_get_str(payload_qstr));
 539         QDECREF(payload_qstr);
 540     } else {
 541         response_qstr = payload_qstr;
 542     }
 543
 544     qstring_append_chr(response_qstr, '\n');
 545     buf = qstring_get_str(response_qstr);
 546     status = ga_channel_write_all(s->channel, buf, strlen(buf));
 547     QDECREF(response_qstr);
 548     if (status != G_IO_STATUS_NORMAL) {
 549         return -EIO;
 550     }
 551
 552     return 0;
 553 }
 554
 555 static void process_command(GAState *s, QDict *req)
 556 {
 557     QObject *rsp = NULL;
 558     int ret;
 559
 560     g_assert(req);
 561     g_debug("processing command");
 562     rsp = qmp_dispatch(QOBJECT(req));
 563     if (rsp) {
 564         ret = send_response(s, rsp);
 565         if (ret) {
 566             g_warning("error sending response: %s", strerror(ret));
 567         }
 568         qobject_decref(rsp);
 569     }
 570 }
 571
 572 /* handle requests/control events coming in over the channel */
 573 static void process_event(JSONMessageParser *parser, QList *tokens)
 574 {
 575     GAState *s = container_of(parser, GAState, parser);
 576     QObject *obj;
 577     QDict *qdict;
 578     Error *err = NULL;
 579     int ret;
 580
 581     g_assert(s && parser);
 582
 583     g_debug("process_event: called");
 584     obj = json_parser_parse_err(tokens, NULL, &err);
 585     if (err || !obj || qobject_type(obj) != QTYPE_QDICT) {
 586         qobject_decref(obj);
 587         qdict = qdict_new();
 588         if (!err) {
 589             g_warning("failed to parse event: unknown error");
 590             error_set(&err, QERR_JSON_PARSING);
 591         } else {
 592             g_warning("failed to parse event: %s", error_get_pretty(err));
 593         }
 594         qdict_put_obj(qdict, "error", qmp_build_error_object(err));
 595         error_free(err);
 596     } else {
 597         qdict = qobject_to_qdict(obj);
 598     }
 599
 600     g_assert(qdict);
 601
 602     /* handle host->guest commands */
 603     if (qdict_haskey(qdict, "execute")) {
 604         process_command(s, qdict);
 605     } else {
 606         if (!qdict_haskey(qdict, "error")) {
 607             QDECREF(qdict);
 608             qdict = qdict_new();
 609             g_warning("unrecognized payload format");
 610             error_set(&err, QERR_UNSUPPORTED);
 611             qdict_put_obj(qdict, "error", qmp_build_error_object(err));
 612             error_free(err);
 613         }
 614         ret = send_response(s, QOBJECT(qdict));
 615         if (ret) {
 616             g_warning("error sending error response: %s", strerror(ret));
 617         }
 618     }
 619
 620     QDECREF(qdict);
 621 }
 622
 623 /* false return signals GAChannel to close the current client connection */
 624 static gboolean channel_event_cb(GIOCondition condition, gpointer data)
 625 {
 626     GAState *s = data;
 627     gchar buf[QGA_READ_COUNT_DEFAULT+1];
 628     gsize count;
 629     GError *err = NULL;
 630     GIOStatus status = ga_channel_read(s->channel, buf, QGA_READ_COUNT_DEFAULT, &count);
 631     if (err != NULL) {
 632         g_warning("error reading channel: %s", err->message);
 633         g_error_free(err);
 634         return false;
 635     }
 636     switch (status) {
 637     case G_IO_STATUS_ERROR:
 638         g_warning("error reading channel");
 639         return false;
 640     case G_IO_STATUS_NORMAL:
 641         buf[count] = 0;
 642         g_debug("read data, count: %d, data: %s", (int)count, buf);
 643         json_message_parser_feed(&s->parser, (char *)buf, (int)count);
 644         break;
 645     case G_IO_STATUS_EOF:
 646         g_debug("received EOF");
 647         if (!s->virtio) {
 648             return false;
 649         }
 650         /* fall through */
 651     case G_IO_STATUS_AGAIN:
 652         /* virtio causes us to spin here when no process is attached to
 653          * host-side chardev. sleep a bit to mitigate this
 654          */
 655         if (s->virtio) {
 656             usleep(100*1000);
 657         }
 658         return true;
 659     default:
 660         g_warning("unknown channel read status, closing");
 661         return false;
 662     }
 663     return true;
 664 }
 665
 666 static gboolean channel_init(GAState *s, const gchar *method, const gchar *path)
 667 {
 668     GAChannelMethod channel_method;
 669
 670     if (method == NULL) {
 671         method = "virtio-serial";
 672     }
 673
 674     if (path == NULL) {
 675         if (strcmp(method, "virtio-serial") != 0) {
 676             g_critical("must specify a path for this channel");
 677             return false;
 678         }
 679         /* try the default path for the virtio-serial port */
 680         path = QGA_VIRTIO_PATH_DEFAULT;
 681     }
 682
 683     if (strcmp(method, "virtio-serial") == 0) {
 684         s->virtio = true; /* virtio requires special handling in some cases */
 685         channel_method = GA_CHANNEL_VIRTIO_SERIAL;
 686     } else if (strcmp(method, "isa-serial") == 0) {
 687         channel_method = GA_CHANNEL_ISA_SERIAL;
 688     } else if (strcmp(method, "unix-listen") == 0) {
 689         channel_method = GA_CHANNEL_UNIX_LISTEN;
 690     } else {
 691         g_critical("unsupported channel method/type: %s", method);
 692         return false;
 693     }
 694
 695     s->channel = ga_channel_new(channel_method, path, channel_event_cb, s);
 696     if (!s->channel) {
 697         g_critical("failed to create guest agent channel");
 698         return false;
 699     }
 700
 701     return true;
 702 }
 703
 704 #ifdef _WIN32
 705 DWORD WINAPI service_ctrl_handler(DWORD ctrl, DWORD type, LPVOID data,
 706                                   LPVOID ctx)
 707 {
 708     DWORD ret = NO_ERROR;
 709     GAService *service = &ga_state->service;
 710
 711     switch (ctrl)
 712     {
 713         case SERVICE_CONTROL_STOP:
 714         case SERVICE_CONTROL_SHUTDOWN:
 715             quit_handler(SIGTERM);
 716             service->status.dwCurrentState = SERVICE_STOP_PENDING;
 717             SetServiceStatus(service->status_handle, &service->status);
 718             break;
 719
 720         default:
 721             ret = ERROR_CALL_NOT_IMPLEMENTED;
 722     }
 723     return ret;
 724 }
 725
 726 VOID WINAPI service_main(DWORD argc, TCHAR *argv[])
 727 {
 728     GAService *service = &ga_state->service;
 729
 730     service->status_handle = RegisterServiceCtrlHandlerEx(QGA_SERVICE_NAME,
 731         service_ctrl_handler, NULL);
 732
 733     if (service->status_handle == 0) {
 734         g_critical("Failed to register extended requests function!\n");
 735         return;
 736     }
 737
 738     service->status.dwServiceType = SERVICE_WIN32;
 739     service->status.dwCurrentState = SERVICE_RUNNING;
 740     service->status.dwControlsAccepted = SERVICE_ACCEPT_STOP | SERVICE_ACCEPT_SHUTDOWN;
 741     service->status.dwWin32ExitCode = NO_ERROR;
 742     service->status.dwServiceSpecificExitCode = NO_ERROR;
 743     service->status.dwCheckPoint = 0;
 744     service->status.dwWaitHint = 0;
 745     SetServiceStatus(service->status_handle, &service->status);
 746
 747     g_main_loop_run(ga_state->main_loop);
 748
 749     service->status.dwCurrentState = SERVICE_STOPPED;
 750     SetServiceStatus(service->status_handle, &service->status);
 751 }
 752 #endif
 753
 754 static void set_persistent_state_defaults(GAPersistentState *pstate)
 755 {
 756     g_assert(pstate);
 757     pstate->fd_counter = QGA_PSTATE_DEFAULT_FD_COUNTER;
 758 }
 759
 760 static void persistent_state_from_keyfile(GAPersistentState *pstate,
 761                                           GKeyFile *keyfile)
 762 {
 763     g_assert(pstate);
 764     g_assert(keyfile);
 765     /* if any fields are missing, either because the file was tampered with
 766      * by agents of chaos, or because the field wasn't present at the time the
 767      * file was created, the best we can ever do is start over with the default
 768      * values. so load them now, and ignore any errors in accessing key-value
 769      * pairs
 770      */
 771     set_persistent_state_defaults(pstate);
 772
 773     if (g_key_file_has_key(keyfile, "global", "fd_counter", NULL)) {
 774         pstate->fd_counter =
 775             g_key_file_get_integer(keyfile, "global", "fd_counter", NULL);
 776     }
 777 }
 778
 779 static void persistent_state_to_keyfile(const GAPersistentState *pstate,
 780                                         GKeyFile *keyfile)
 781 {
 782     g_assert(pstate);
 783     g_assert(keyfile);
 784
 785     g_key_file_set_integer(keyfile, "global", "fd_counter", pstate->fd_counter);
 786 }
 787
 788 static gboolean write_persistent_state(const GAPersistentState *pstate,
 789                                        const gchar *path)
 790 {
 791     GKeyFile *keyfile = g_key_file_new();
 792     GError *gerr = NULL;
 793     gboolean ret = true;
 794     gchar *data = NULL;
 795     gsize data_len;
 796
 797     g_assert(pstate);
 798
 799     persistent_state_to_keyfile(pstate, keyfile);
 800     data = g_key_file_to_data(keyfile, &data_len, &gerr);
 801     if (gerr) {
 802         g_critical("failed to convert persistent state to string: %s",
 803                    gerr->message);
 804         ret = false;
 805         goto out;
 806     }
 807
 808     g_file_set_contents(path, data, data_len, &gerr);
 809     if (gerr) {
 810         g_critical("failed to write persistent state to %s: %s",
 811                     path, gerr->message);
 812         ret = false;
 813         goto out;
 814     }
 815
 816 out:
 817     if (gerr) {
 818         g_error_free(gerr);
 819     }
 820     if (keyfile) {
 821         g_key_file_free(keyfile);
 822     }
 823     g_free(data);
 824     return ret;
 825 }
 826
 827 static gboolean read_persistent_state(GAPersistentState *pstate,
 828                                       const gchar *path, gboolean frozen)
 829 {
 830     GKeyFile *keyfile = NULL;
 831     GError *gerr = NULL;
 832     struct stat st;
 833     gboolean ret = true;
 834
 835     g_assert(pstate);
 836
 837     if (stat(path, &st) == -1) {
 838         /* it's okay if state file doesn't exist, but any other error
 839          * indicates a permissions issue or some other misconfiguration
 840          * that we likely won't be able to recover from.
 841          */
 842         if (errno != ENOENT) {
 843             g_critical("unable to access state file at path %s: %s",
 844                        path, strerror(errno));
 845             ret = false;
 846             goto out;
 847         }
 848
 849         /* file doesn't exist. initialize state to default values and
 850          * attempt to save now. (we could wait till later when we have
 851          * modified state we need to commit, but if there's a problem,
 852          * such as a missing parent directory, we want to catch it now)
 853          *
 854          * there is a potential scenario where someone either managed to
 855          * update the agent from a version that didn't use a key store
 856          * while qemu-ga thought the filesystem was frozen, or
 857          * deleted the key store prior to issuing a fsfreeze, prior
 858          * to restarting the agent. in this case we go ahead and defer
 859          * initial creation till we actually have modified state to
 860          * write, otherwise fail to recover from freeze.
 861          */
 862         set_persistent_state_defaults(pstate);
 863         if (!frozen) {
 864             ret = write_persistent_state(pstate, path);
 865             if (!ret) {
 866                 g_critical("unable to create state file at path %s", path);
 867                 ret = false;
 868                 goto out;
 869             }
 870         }
 871         ret = true;
 872         goto out;
 873     }
 874
 875     keyfile = g_key_file_new();
 876     g_key_file_load_from_file(keyfile, path, 0, &gerr);
 877     if (gerr) {
 878         g_critical("error loading persistent state from path: %s, %s",
 879                    path, gerr->message);
 880         ret = false;
 881         goto out;
 882     }
 883
 884     persistent_state_from_keyfile(pstate, keyfile);
 885
 886 out:
 887     if (keyfile) {
 888         g_key_file_free(keyfile);
 889     }
 890     if (gerr) {
 891         g_error_free(gerr);
 892     }
 893
 894     return ret;
 895 }
 896
 897 int64_t ga_get_fd_handle(GAState *s, Error **errp)
 898 {
 899     int64_t handle;
 900
 901     g_assert(s->pstate_filepath);
 902     /* we blacklist commands and avoid operations that potentially require
 903      * writing to disk when we're in a frozen state. this includes opening
 904      * new files, so we should never get here in that situation
 905      */
 906     g_assert(!ga_is_frozen(s));
 907
 908     handle = s->pstate.fd_counter++;
 909
 910     /* This should never happen on a reasonable timeframe, as guest-file-open
 911      * would have to be issued 2^63 times */
 912     if (s->pstate.fd_counter == INT64_MAX) {
 913         abort();
 914     }
 915
 916     if (!write_persistent_state(&s->pstate, s->pstate_filepath)) {
 917         error_setg(errp, "failed to commit persistent state to disk");
 918     }
 919
 920     return handle;
 921 }
 922
 923 int main(int argc, char **argv)
 924 {
 925     const char *sopt = "hVvdm:p:l:f:F::b:s:t:";
 926     const char *method = NULL, *path = NULL;
 927     const char *log_filepath = NULL;
 928     const char *pid_filepath;
 929 #ifdef CONFIG_FSFREEZE
 930     const char *fsfreeze_hook = NULL;
 931 #endif
 932     const char *state_dir;
 933 #ifdef _WIN32
 934     const char *service = NULL;
 935 #endif
 936     const struct option lopt[] = {
 937         { "help", 0, NULL, 'h' },
 938         { "version", 0, NULL, 'V' },
 939         { "logfile", 1, NULL, 'l' },
 940         { "pidfile", 1, NULL, 'f' },
 941 #ifdef CONFIG_FSFREEZE
 942         { "fsfreeze-hook", 2, NULL, 'F' },
 943 #endif
 944         { "verbose", 0, NULL, 'v' },
 945         { "method", 1, NULL, 'm' },
 946         { "path", 1, NULL, 'p' },
 947         { "daemonize", 0, NULL, 'd' },
 948         { "blacklist", 1, NULL, 'b' },
 949 #ifdef _WIN32
 950         { "service", 1, NULL, 's' },
 951 #endif
 952         { "statedir", 1, NULL, 't' },
 953         { NULL, 0, NULL, 0 }
 954     };
 955     int opt_ind = 0, ch, daemonize = 0, i, j, len;
 956     GLogLevelFlags log_level = G_LOG_LEVEL_ERROR | G_LOG_LEVEL_CRITICAL;
 957     GList *blacklist = NULL;
 958     GAState *s;
 959
 960     module_call_init(MODULE_INIT_QAPI);
 961
 962     init_dfl_pathnames();
 963     pid_filepath = dfl_pathnames.pidfile;
 964     state_dir = dfl_pathnames.state_dir;
 965
 966     while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
 967         switch (ch) {
 968         case 'm':
 969             method = optarg;
 970             break;
 971         case 'p':
 972             path = optarg;
 973             break;
 974         case 'l':
 975             log_filepath = optarg;
 976             break;
 977         case 'f':
 978             pid_filepath = optarg;
 979             break;
 980 #ifdef CONFIG_FSFREEZE
 981         case 'F':
 982             fsfreeze_hook = optarg ? optarg : QGA_FSFREEZE_HOOK_DEFAULT;
 983             break;
 984 #endif
 985         case 't':
 986              state_dir = optarg;
 987              break;
 988         case 'v':
 989             /* enable all log levels */
 990             log_level = G_LOG_LEVEL_MASK;
 991             break;
 992         case 'V':
 993             printf("QEMU Guest Agent %s\n", QEMU_VERSION);
 994             return 0;
 995         case 'd':
 996             daemonize = 1;
 997             break;
 998         case 'b': {
 999             char **list_head, **list;
1000             if (is_help_option(optarg)) {
1001                 list_head = list = qmp_get_command_list();
1002                 while (*list != NULL) {
1003                     printf("%s\n", *list);
1004                     g_free(*list);
1005                     list++;
1006                 }
1007                 g_free(list_head);
1008                 return 0;
1009             }
1010             for (j = 0, i = 0, len = strlen(optarg); i < len; i++) {
1011                 if (optarg[i] == ',') {
1012                     optarg[i] = 0;
1013                     blacklist = g_list_append(blacklist, &optarg[j]);
1014                     j = i + 1;
1015                 }
1016             }
1017             if (j < i) {
1018                 blacklist = g_list_append(blacklist, &optarg[j]);
1019             }
1020             break;
1021         }
1022 #ifdef _WIN32
1023         case 's':
1024             service = optarg;
1025             if (strcmp(service, "install") == 0) {
1026                 const char *fixed_state_dir;
1027
1028                 /* If the user passed the "-t" option, we save that state dir
1029                  * in the service. Otherwise we let the service fetch the state
1030                  * dir from the environment when it starts.
1031                  */
1032                 fixed_state_dir = (state_dir == dfl_pathnames.state_dir) ?
1033                                   NULL :
1034                                   state_dir;
1035                 if (ga_install_vss_provider()) {
1036                     return EXIT_FAILURE;
1037                 }
1038                 if (ga_install_service(path, log_filepath, fixed_state_dir)) {
1039                     return EXIT_FAILURE;
1040                 }
1041                 return 0;
1042             } else if (strcmp(service, "uninstall") == 0) {
1043                 ga_uninstall_vss_provider();
1044                 return ga_uninstall_service();
1045             } else {
1046                 printf("Unknown service command.\n");
1047                 return EXIT_FAILURE;
1048             }
1049             break;
1050 #endif
1051         case 'h':
1052             usage(argv[0]);
1053             return 0;
1054         case '?':
1055             g_print("Unknown option, try '%s --help' for more information.\n",
1056                     argv[0]);
1057             return EXIT_FAILURE;
1058         }
1059     }
1060
1061 #ifdef _WIN32
1062     /* On win32 the state directory is application specific (be it the default
1063      * or a user override). We got past the command line parsing; let's create
1064      * the directory (with any intermediate directories). If we run into an
1065      * error later on, we won't try to clean up the directory, it is considered
1066      * persistent.
1067      */
1068     if (g_mkdir_with_parents(state_dir, S_IRWXU) == -1) {
1069         g_critical("unable to create (an ancestor of) the state directory"
1070                    " '%s': %s", state_dir, strerror(errno));
1071         return EXIT_FAILURE;
1072     }
1073 #endif
1074
1075     s = g_malloc0(sizeof(GAState));
1076     s->log_level = log_level;
1077     s->log_file = stderr;
1078 #ifdef CONFIG_FSFREEZE
1079     s->fsfreeze_hook = fsfreeze_hook;
1080 #endif
1081     g_log_set_default_handler(ga_log, s);
1082     g_log_set_fatal_mask(NULL, G_LOG_LEVEL_ERROR);
1083     ga_enable_logging(s);
1084     s->state_filepath_isfrozen = g_strdup_printf("%s/qga.state.isfrozen",
1085                                                  state_dir);
1086     s->pstate_filepath = g_strdup_printf("%s/qga.state", state_dir);
1087     s->frozen = false;
1088
1089 #ifndef _WIN32
1090     /* check if a previous instance of qemu-ga exited with filesystems' state
1091      * marked as frozen. this could be a stale value (a non-qemu-ga process
1092      * or reboot may have since unfrozen them), but better to require an
1093      * uneeded unfreeze than to risk hanging on start-up
1094      */
1095     struct stat st;
1096     if (stat(s->state_filepath_isfrozen, &st) == -1) {
1097         /* it's okay if the file doesn't exist, but if we can't access for
1098          * some other reason, such as permissions, there's a configuration
1099          * that needs to be addressed. so just bail now before we get into
1100          * more trouble later
1101          */
1102         if (errno != ENOENT) {
1103             g_critical("unable to access state file at path %s: %s",
1104                        s->state_filepath_isfrozen, strerror(errno));
1105             return EXIT_FAILURE;
1106         }
1107     } else {
1108         g_warning("previous instance appears to have exited with frozen"
1109                   " filesystems. deferring logging/pidfile creation and"
1110                   " disabling non-fsfreeze-safe commands until"
1111                   " guest-fsfreeze-thaw is issued, or filesystems are"
1112                   " manually unfrozen and the file %s is removed",
1113                   s->state_filepath_isfrozen);
1114         s->frozen = true;
1115     }
1116 #endif
1117
1118     if (ga_is_frozen(s)) {
1119         if (daemonize) {
1120             /* delay opening/locking of pidfile till filesystem are unfrozen */
1121             s->deferred_options.pid_filepath = pid_filepath;
1122             become_daemon(NULL);
1123         }
1124         if (log_filepath) {
1125             /* delay opening the log file till filesystems are unfrozen */
1126             s->deferred_options.log_filepath = log_filepath;
1127         }
1128         ga_disable_logging(s);
1129         ga_disable_non_whitelisted();
1130     } else {
1131         if (daemonize) {
1132             become_daemon(pid_filepath);
1133         }
1134         if (log_filepath) {
1135             FILE *log_file = ga_open_logfile(log_filepath);
1136             if (!log_file) {
1137                 g_critical("unable to open specified log file: %s",
1138                            strerror(errno));
1139                 goto out_bad;
1140             }
1141             s->log_file = log_file;
1142         }
1143     }
1144
1145     /* load persistent state from disk */
1146     if (!read_persistent_state(&s->pstate,
1147                                s->pstate_filepath,
1148                                ga_is_frozen(s))) {
1149         g_critical("failed to load persistent state");
1150         goto out_bad;
1151     }
1152
1153     if (blacklist) {
1154         s->blacklist = blacklist;
1155         do {
1156             g_debug("disabling command: %s", (char *)blacklist->data);
1157             qmp_disable_command(blacklist->data);
1158             blacklist = g_list_next(blacklist);
1159         } while (blacklist);
1160     }
1161     s->command_state = ga_command_state_new();
1162     ga_command_state_init(s, s->command_state);
1163     ga_command_state_init_all(s->command_state);
1164     json_message_parser_init(&s->parser, process_event);
1165     ga_state = s;
1166 #ifndef _WIN32
1167     if (!register_signal_handlers()) {
1168         g_critical("failed to register signal handlers");
1169         goto out_bad;
1170     }
1171 #endif
1172
1173     s->main_loop = g_main_loop_new(NULL, false);
1174     if (!channel_init(ga_state, method, path)) {
1175         g_critical("failed to initialize guest agent channel");
1176         goto out_bad;
1177     }
1178 #ifndef _WIN32
1179     g_main_loop_run(ga_state->main_loop);
1180 #else
1181     if (daemonize) {
1182         SERVICE_TABLE_ENTRY service_table[] = {
1183             { (char *)QGA_SERVICE_NAME, service_main }, { NULL, NULL } };
1184         StartServiceCtrlDispatcher(service_table);
1185     } else {
1186         g_main_loop_run(ga_state->main_loop);
1187     }
1188 #endif
1189
1190     ga_command_state_cleanup_all(ga_state->command_state);
1191     ga_channel_free(ga_state->channel);
1192
1193     if (daemonize) {
1194         unlink(pid_filepath);
1195     }
1196     return 0;
1197
1198 out_bad:
1199     if (daemonize) {
1200         unlink(pid_filepath);
1201     }
1202     return EXIT_FAILURE;
1203 }