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     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     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, vss-install, vss-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 (g_strcmp0(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_setg(&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_setg(&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 (strcmp(method, "virtio-serial") == 0) {
 662         s->virtio = true; /* virtio requires special handling in some cases */
 663         channel_method = GA_CHANNEL_VIRTIO_SERIAL;
 664     } else if (strcmp(method, "isa-serial") == 0) {
 665         channel_method = GA_CHANNEL_ISA_SERIAL;
 666     } else if (strcmp(method, "unix-listen") == 0) {
 667         channel_method = GA_CHANNEL_UNIX_LISTEN;
 668     } else {
 669         g_critical("unsupported channel method/type: %s", method);
 670         return false;
 671     }
 672
 673     s->channel = ga_channel_new(channel_method, path, channel_event_cb, s);
 674     if (!s->channel) {
 675         g_critical("failed to create guest agent channel");
 676         return false;
 677     }
 678
 679     return true;
 680 }
 681
 682 #ifdef _WIN32
 683 DWORD WINAPI service_ctrl_handler(DWORD ctrl, DWORD type, LPVOID data,
 684                                   LPVOID ctx)
 685 {
 686     DWORD ret = NO_ERROR;
 687     GAService *service = &ga_state->service;
 688
 689     switch (ctrl)
 690     {
 691         case SERVICE_CONTROL_STOP:
 692         case SERVICE_CONTROL_SHUTDOWN:
 693             quit_handler(SIGTERM);
 694             service->status.dwCurrentState = SERVICE_STOP_PENDING;
 695             SetServiceStatus(service->status_handle, &service->status);
 696             break;
 697
 698         default:
 699             ret = ERROR_CALL_NOT_IMPLEMENTED;
 700     }
 701     return ret;
 702 }
 703
 704 VOID WINAPI service_main(DWORD argc, TCHAR *argv[])
 705 {
 706     GAService *service = &ga_state->service;
 707
 708     service->status_handle = RegisterServiceCtrlHandlerEx(QGA_SERVICE_NAME,
 709         service_ctrl_handler, NULL);
 710
 711     if (service->status_handle == 0) {
 712         g_critical("Failed to register extended requests function!\n");
 713         return;
 714     }
 715
 716     service->status.dwServiceType = SERVICE_WIN32;
 717     service->status.dwCurrentState = SERVICE_RUNNING;
 718     service->status.dwControlsAccepted = SERVICE_ACCEPT_STOP | SERVICE_ACCEPT_SHUTDOWN;
 719     service->status.dwWin32ExitCode = NO_ERROR;
 720     service->status.dwServiceSpecificExitCode = NO_ERROR;
 721     service->status.dwCheckPoint = 0;
 722     service->status.dwWaitHint = 0;
 723     SetServiceStatus(service->status_handle, &service->status);
 724
 725     g_main_loop_run(ga_state->main_loop);
 726
 727     service->status.dwCurrentState = SERVICE_STOPPED;
 728     SetServiceStatus(service->status_handle, &service->status);
 729 }
 730 #endif
 731
 732 static void set_persistent_state_defaults(GAPersistentState *pstate)
 733 {
 734     g_assert(pstate);
 735     pstate->fd_counter = QGA_PSTATE_DEFAULT_FD_COUNTER;
 736 }
 737
 738 static void persistent_state_from_keyfile(GAPersistentState *pstate,
 739                                           GKeyFile *keyfile)
 740 {
 741     g_assert(pstate);
 742     g_assert(keyfile);
 743     /* if any fields are missing, either because the file was tampered with
 744      * by agents of chaos, or because the field wasn't present at the time the
 745      * file was created, the best we can ever do is start over with the default
 746      * values. so load them now, and ignore any errors in accessing key-value
 747      * pairs
 748      */
 749     set_persistent_state_defaults(pstate);
 750
 751     if (g_key_file_has_key(keyfile, "global", "fd_counter", NULL)) {
 752         pstate->fd_counter =
 753             g_key_file_get_integer(keyfile, "global", "fd_counter", NULL);
 754     }
 755 }
 756
 757 static void persistent_state_to_keyfile(const GAPersistentState *pstate,
 758                                         GKeyFile *keyfile)
 759 {
 760     g_assert(pstate);
 761     g_assert(keyfile);
 762
 763     g_key_file_set_integer(keyfile, "global", "fd_counter", pstate->fd_counter);
 764 }
 765
 766 static gboolean write_persistent_state(const GAPersistentState *pstate,
 767                                        const gchar *path)
 768 {
 769     GKeyFile *keyfile = g_key_file_new();
 770     GError *gerr = NULL;
 771     gboolean ret = true;
 772     gchar *data = NULL;
 773     gsize data_len;
 774
 775     g_assert(pstate);
 776
 777     persistent_state_to_keyfile(pstate, keyfile);
 778     data = g_key_file_to_data(keyfile, &data_len, &gerr);
 779     if (gerr) {
 780         g_critical("failed to convert persistent state to string: %s",
 781                    gerr->message);
 782         ret = false;
 783         goto out;
 784     }
 785
 786     g_file_set_contents(path, data, data_len, &gerr);
 787     if (gerr) {
 788         g_critical("failed to write persistent state to %s: %s",
 789                     path, gerr->message);
 790         ret = false;
 791         goto out;
 792     }
 793
 794 out:
 795     if (gerr) {
 796         g_error_free(gerr);
 797     }
 798     if (keyfile) {
 799         g_key_file_free(keyfile);
 800     }
 801     g_free(data);
 802     return ret;
 803 }
 804
 805 static gboolean read_persistent_state(GAPersistentState *pstate,
 806                                       const gchar *path, gboolean frozen)
 807 {
 808     GKeyFile *keyfile = NULL;
 809     GError *gerr = NULL;
 810     struct stat st;
 811     gboolean ret = true;
 812
 813     g_assert(pstate);
 814
 815     if (stat(path, &st) == -1) {
 816         /* it's okay if state file doesn't exist, but any other error
 817          * indicates a permissions issue or some other misconfiguration
 818          * that we likely won't be able to recover from.
 819          */
 820         if (errno != ENOENT) {
 821             g_critical("unable to access state file at path %s: %s",
 822                        path, strerror(errno));
 823             ret = false;
 824             goto out;
 825         }
 826
 827         /* file doesn't exist. initialize state to default values and
 828          * attempt to save now. (we could wait till later when we have
 829          * modified state we need to commit, but if there's a problem,
 830          * such as a missing parent directory, we want to catch it now)
 831          *
 832          * there is a potential scenario where someone either managed to
 833          * update the agent from a version that didn't use a key store
 834          * while qemu-ga thought the filesystem was frozen, or
 835          * deleted the key store prior to issuing a fsfreeze, prior
 836          * to restarting the agent. in this case we go ahead and defer
 837          * initial creation till we actually have modified state to
 838          * write, otherwise fail to recover from freeze.
 839          */
 840         set_persistent_state_defaults(pstate);
 841         if (!frozen) {
 842             ret = write_persistent_state(pstate, path);
 843             if (!ret) {
 844                 g_critical("unable to create state file at path %s", path);
 845                 ret = false;
 846                 goto out;
 847             }
 848         }
 849         ret = true;
 850         goto out;
 851     }
 852
 853     keyfile = g_key_file_new();
 854     g_key_file_load_from_file(keyfile, path, 0, &gerr);
 855     if (gerr) {
 856         g_critical("error loading persistent state from path: %s, %s",
 857                    path, gerr->message);
 858         ret = false;
 859         goto out;
 860     }
 861
 862     persistent_state_from_keyfile(pstate, keyfile);
 863
 864 out:
 865     if (keyfile) {
 866         g_key_file_free(keyfile);
 867     }
 868     if (gerr) {
 869         g_error_free(gerr);
 870     }
 871
 872     return ret;
 873 }
 874
 875 int64_t ga_get_fd_handle(GAState *s, Error **errp)
 876 {
 877     int64_t handle;
 878
 879     g_assert(s->pstate_filepath);
 880     /* we blacklist commands and avoid operations that potentially require
 881      * writing to disk when we're in a frozen state. this includes opening
 882      * new files, so we should never get here in that situation
 883      */
 884     g_assert(!ga_is_frozen(s));
 885
 886     handle = s->pstate.fd_counter++;
 887
 888     /* This should never happen on a reasonable timeframe, as guest-file-open
 889      * would have to be issued 2^63 times */
 890     if (s->pstate.fd_counter == INT64_MAX) {
 891         abort();
 892     }
 893
 894     if (!write_persistent_state(&s->pstate, s->pstate_filepath)) {
 895         error_setg(errp, "failed to commit persistent state to disk");
 896         return -1;
 897     }
 898
 899     return handle;
 900 }
 901
 902 static void ga_print_cmd(QmpCommand *cmd, void *opaque)
 903 {
 904     printf("%s\n", qmp_command_name(cmd));
 905 }
 906
 907 static GList *split_list(const gchar *str, const gchar *delim)
 908 {
 909     GList *list = NULL;
 910     int i;
 911     gchar **strv;
 912
 913     strv = g_strsplit(str, delim, -1);
 914     for (i = 0; strv[i]; i++) {
 915         list = g_list_prepend(list, strv[i]);
 916     }
 917     g_free(strv);
 918
 919     return list;
 920 }
 921
 922 typedef struct GAConfig {
 923     char *channel_path;
 924     char *method;
 925     char *log_filepath;
 926     char *pid_filepath;
 927 #ifdef CONFIG_FSFREEZE
 928     char *fsfreeze_hook;
 929 #endif
 930     char *state_dir;
 931 #ifdef _WIN32
 932     const char *service;
 933 #endif
 934     GList *blacklist;
 935     int daemonize;
 936     GLogLevelFlags log_level;
 937 } GAConfig;
 938
 939 static GAConfig *config_parse(int argc, char **argv)
 940 {
 941     GAConfig *config = g_new0(GAConfig, 1);
 942     const char *sopt = "hVvdm:p:l:f:F::b:s:t:D";
 943     int opt_ind = 0, ch;
 944     const struct option lopt[] = {
 945         { "help", 0, NULL, 'h' },
 946         { "version", 0, NULL, 'V' },
 947         { "logfile", 1, NULL, 'l' },
 948         { "pidfile", 1, NULL, 'f' },
 949 #ifdef CONFIG_FSFREEZE
 950         { "fsfreeze-hook", 2, NULL, 'F' },
 951 #endif
 952         { "verbose", 0, NULL, 'v' },
 953         { "method", 1, NULL, 'm' },
 954         { "path", 1, NULL, 'p' },
 955         { "daemonize", 0, NULL, 'd' },
 956         { "blacklist", 1, NULL, 'b' },
 957 #ifdef _WIN32
 958         { "service", 1, NULL, 's' },
 959 #endif
 960         { "statedir", 1, NULL, 't' },
 961         { NULL, 0, NULL, 0 }
 962     };
 963
 964     config->log_level = G_LOG_LEVEL_ERROR | G_LOG_LEVEL_CRITICAL;
 965
 966     while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
 967         switch (ch) {
 968         case 'm':
 969             config->method = g_strdup(optarg);
 970             break;
 971         case 'p':
 972             config->channel_path = g_strdup(optarg);
 973             break;
 974         case 'l':
 975             config->log_filepath = g_strdup(optarg);
 976             break;
 977         case 'f':
 978             config->pid_filepath = g_strdup(optarg);
 979             break;
 980 #ifdef CONFIG_FSFREEZE
 981         case 'F':
 982             config->fsfreeze_hook = g_strdup(optarg ?: QGA_FSFREEZE_HOOK_DEFAULT);
 983             break;
 984 #endif
 985         case 't':
 986             config->state_dir = g_strdup(optarg);
 987             break;
 988         case 'v':
 989             /* enable all log levels */
 990             config->log_level = G_LOG_LEVEL_MASK;
 991             break;
 992         case 'V':
 993             printf("QEMU Guest Agent %s\n", QEMU_VERSION);
 994             exit(EXIT_SUCCESS);
 995         case 'd':
 996             config->daemonize = 1;
 997             break;
 998         case 'b': {
 999             if (is_help_option(optarg)) {
1000                 qmp_for_each_command(ga_print_cmd, NULL);
1001                 exit(EXIT_SUCCESS);
1002             }
1003             config->blacklist = g_list_concat(config->blacklist,
1004                                              split_list(optarg, ","));
1005             break;
1006         }
1007 #ifdef _WIN32
1008         case 's':
1009             config->service = optarg;
1010             if (strcmp(config->service, "install") == 0) {
1011                 if (ga_install_vss_provider()) {
1012                     exit(EXIT_FAILURE);
1013                 }
1014                 if (ga_install_service(config->channel_path,
1015                                        config->log_filepath, config->state_dir)) {
1016                     exit(EXIT_FAILURE);
1017                 }
1018                 exit(EXIT_SUCCESS);
1019             } else if (strcmp(config->service, "uninstall") == 0) {
1020                 ga_uninstall_vss_provider();
1021                 exit(ga_uninstall_service());
1022             } else if (strcmp(config->service, "vss-install") == 0) {
1023                 if (ga_install_vss_provider()) {
1024                     exit(EXIT_FAILURE);
1025                 }
1026                 exit(EXIT_SUCCESS);
1027             } else if (strcmp(config->service, "vss-uninstall") == 0) {
1028                 ga_uninstall_vss_provider();
1029                 exit(EXIT_SUCCESS);
1030             } else {
1031                 printf("Unknown service command.\n");
1032                 exit(EXIT_FAILURE);
1033             }
1034             break;
1035 #endif
1036         case 'h':
1037             usage(argv[0]);
1038             exit(EXIT_SUCCESS);
1039         case '?':
1040             g_print("Unknown option, try '%s --help' for more information.\n",
1041                     argv[0]);
1042             exit(EXIT_FAILURE);
1043         }
1044     }
1045
1046     return config;
1047 }
1048
1049 static void config_free(GAConfig *config)
1050 {
1051     g_free(config->method);
1052     g_free(config->log_filepath);
1053     g_free(config->pid_filepath);
1054     g_free(config->state_dir);
1055     g_free(config->channel_path);
1056 #ifdef CONFIG_FSFREEZE
1057     g_free(config->fsfreeze_hook);
1058 #endif
1059     g_free(config);
1060 }
1061
1062 static bool check_is_frozen(GAState *s)
1063 {
1064 #ifndef _WIN32
1065     /* check if a previous instance of qemu-ga exited with filesystems' state
1066      * marked as frozen. this could be a stale value (a non-qemu-ga process
1067      * or reboot may have since unfrozen them), but better to require an
1068      * uneeded unfreeze than to risk hanging on start-up
1069      */
1070     struct stat st;
1071     if (stat(s->state_filepath_isfrozen, &st) == -1) {
1072         /* it's okay if the file doesn't exist, but if we can't access for
1073          * some other reason, such as permissions, there's a configuration
1074          * that needs to be addressed. so just bail now before we get into
1075          * more trouble later
1076          */
1077         if (errno != ENOENT) {
1078             g_critical("unable to access state file at path %s: %s",
1079                        s->state_filepath_isfrozen, strerror(errno));
1080             return EXIT_FAILURE;
1081         }
1082     } else {
1083         g_warning("previous instance appears to have exited with frozen"
1084                   " filesystems. deferring logging/pidfile creation and"
1085                   " disabling non-fsfreeze-safe commands until"
1086                   " guest-fsfreeze-thaw is issued, or filesystems are"
1087                   " manually unfrozen and the file %s is removed",
1088                   s->state_filepath_isfrozen);
1089         return true;
1090     }
1091 #endif
1092     return false;
1093 }
1094
1095 static int run_agent(GAState *s, GAConfig *config)
1096 {
1097     ga_state = s;
1098
1099     g_log_set_default_handler(ga_log, s);
1100     g_log_set_fatal_mask(NULL, G_LOG_LEVEL_ERROR);
1101     ga_enable_logging(s);
1102
1103 #ifdef _WIN32
1104     /* On win32 the state directory is application specific (be it the default
1105      * or a user override). We got past the command line parsing; let's create
1106      * the directory (with any intermediate directories). If we run into an
1107      * error later on, we won't try to clean up the directory, it is considered
1108      * persistent.
1109      */
1110     if (g_mkdir_with_parents(config->state_dir, S_IRWXU) == -1) {
1111         g_critical("unable to create (an ancestor of) the state directory"
1112                    " '%s': %s", config->state_dir, strerror(errno));
1113         return EXIT_FAILURE;
1114     }
1115 #endif
1116
1117     if (ga_is_frozen(s)) {
1118         if (config->daemonize) {
1119             /* delay opening/locking of pidfile till filesystems are unfrozen */
1120             s->deferred_options.pid_filepath = config->pid_filepath;
1121             become_daemon(NULL);
1122         }
1123         if (config->log_filepath) {
1124             /* delay opening the log file till filesystems are unfrozen */
1125             s->deferred_options.log_filepath = config->log_filepath;
1126         }
1127         ga_disable_logging(s);
1128         qmp_for_each_command(ga_disable_non_whitelisted, NULL);
1129     } else {
1130         if (config->daemonize) {
1131             become_daemon(config->pid_filepath);
1132         }
1133         if (config->log_filepath) {
1134             FILE *log_file = ga_open_logfile(config->log_filepath);
1135             if (!log_file) {
1136                 g_critical("unable to open specified log file: %s",
1137                            strerror(errno));
1138                 return EXIT_FAILURE;
1139             }
1140             s->log_file = log_file;
1141         }
1142     }
1143
1144     /* load persistent state from disk */
1145     if (!read_persistent_state(&s->pstate,
1146                                s->pstate_filepath,
1147                                ga_is_frozen(s))) {
1148         g_critical("failed to load persistent state");
1149         return EXIT_FAILURE;
1150     }
1151
1152     config->blacklist = ga_command_blacklist_init(config->blacklist);
1153     if (config->blacklist) {
1154         GList *l = config->blacklist;
1155         s->blacklist = config->blacklist;
1156         do {
1157             g_debug("disabling command: %s", (char *)l->data);
1158             qmp_disable_command(l->data);
1159             l = g_list_next(l);
1160         } while (l);
1161     }
1162     s->command_state = ga_command_state_new();
1163     ga_command_state_init(s, s->command_state);
1164     ga_command_state_init_all(s->command_state);
1165     json_message_parser_init(&s->parser, process_event);
1166     ga_state = s;
1167 #ifndef _WIN32
1168     if (!register_signal_handlers()) {
1169         g_critical("failed to register signal handlers");
1170         return EXIT_FAILURE;
1171     }
1172 #endif
1173
1174     s->main_loop = g_main_loop_new(NULL, false);
1175     if (!channel_init(ga_state, config->method, config->channel_path)) {
1176         g_critical("failed to initialize guest agent channel");
1177         return EXIT_FAILURE;
1178     }
1179 #ifndef _WIN32
1180     g_main_loop_run(ga_state->main_loop);
1181 #else
1182     if (config->daemonize) {
1183         SERVICE_TABLE_ENTRY service_table[] = {
1184             { (char *)QGA_SERVICE_NAME, service_main }, { NULL, NULL } };
1185         StartServiceCtrlDispatcher(service_table);
1186     } else {
1187         g_main_loop_run(ga_state->main_loop);
1188     }
1189 #endif
1190
1191     return EXIT_SUCCESS;
1192 }
1193
1194 static void free_blacklist_entry(gpointer entry, gpointer unused)
1195 {
1196     g_free(entry);
1197 }
1198
1199 int main(int argc, char **argv)
1200 {
1201     int ret = EXIT_SUCCESS;
1202     GAState *s = g_new0(GAState, 1);
1203     GAConfig *config;
1204
1205     module_call_init(MODULE_INIT_QAPI);
1206
1207     init_dfl_pathnames();
1208
1209     config = config_parse(argc, argv);
1210
1211     if (config->pid_filepath == NULL) {
1212         config->pid_filepath = g_strdup(dfl_pathnames.pidfile);
1213     }
1214
1215     if (config->state_dir == NULL) {
1216         config->state_dir = g_strdup(dfl_pathnames.state_dir);
1217     }
1218
1219     if (config->method == NULL) {
1220         config->method = g_strdup("virtio-serial");
1221     }
1222
1223     if (config->channel_path == NULL) {
1224         if (strcmp(config->method, "virtio-serial") == 0) {
1225             /* try the default path for the virtio-serial port */
1226             config->channel_path = g_strdup(QGA_VIRTIO_PATH_DEFAULT);
1227         } else if (strcmp(config->method, "isa-serial") == 0) {
1228             /* try the default path for the serial port - COM1 */
1229             config->channel_path = g_strdup(QGA_SERIAL_PATH_DEFAULT);
1230         } else {
1231             g_critical("must specify a path for this channel");
1232             ret = EXIT_FAILURE;
1233             goto end;
1234         }
1235     }
1236
1237     s->log_level = config->log_level;
1238     s->log_file = stderr;
1239 #ifdef CONFIG_FSFREEZE
1240     s->fsfreeze_hook = config->fsfreeze_hook;
1241 #endif
1242     s->pstate_filepath = g_strdup_printf("%s/qga.state", config->state_dir);
1243     s->state_filepath_isfrozen = g_strdup_printf("%s/qga.state.isfrozen",
1244                                                  config->state_dir);
1245     s->frozen = check_is_frozen(s);
1246
1247     ret = run_agent(s, config);
1248
1249 end:
1250     if (s->command_state) {
1251         ga_command_state_cleanup_all(s->command_state);
1252     }
1253     if (s->channel) {
1254         ga_channel_free(s->channel);
1255     }
1256     g_list_foreach(config->blacklist, free_blacklist_entry, NULL);
1257     g_free(s->pstate_filepath);
1258     g_free(s->state_filepath_isfrozen);
1259
1260     if (config->daemonize) {
1261         unlink(config->pid_filepath);
1262     }
1263
1264     config_free(config);
1265
1266     return ret;
1267 }