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