scsi: pvscsi: check command descriptor ring buffer size (CVE-2016-4952)
[qemu.git] / 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 "qemu/osdep.h"
14 #include <glib.h>
15 #include <getopt.h>
16 #include <glib/gstdio.h>
17 #ifndef _WIN32
18 #include <syslog.h>
19 #include <sys/wait.h>
20 #endif
21 #include "qapi/qmp/json-streamer.h"
22 #include "qapi/qmp/json-parser.h"
23 #include "qapi/qmp/qint.h"
24 #include "qapi/qmp/qjson.h"
25 #include "qga/guest-agent-core.h"
26 #include "qemu/module.h"
27 #include "qapi/qmp/qerror.h"
28 #include "qapi/qmp/dispatch.h"
29 #include "qga/channel.h"
30 #include "qemu/bswap.h"
31 #include "qemu/help_option.h"
32 #ifdef _WIN32
33 #include "qga/service-win32.h"
34 #include "qga/vss-win32.h"
35 #endif
36 #ifdef __linux__
37 #include <linux/fs.h>
38 #ifdef FIFREEZE
39 #define CONFIG_FSFREEZE
40 #endif
41 #endif
42
43 #ifndef _WIN32
44 #define QGA_VIRTIO_PATH_DEFAULT "/dev/virtio-ports/org.qemu.guest_agent.0"
45 #define QGA_STATE_RELATIVE_DIR "run"
46 #define QGA_SERIAL_PATH_DEFAULT "/dev/ttyS0"
47 #else
48 #define QGA_VIRTIO_PATH_DEFAULT "\\\\.\\Global\\org.qemu.guest_agent.0"
49 #define QGA_STATE_RELATIVE_DIR "qemu-ga"
50 #define QGA_SERIAL_PATH_DEFAULT "COM1"
51 #endif
52 #ifdef CONFIG_FSFREEZE
53 #define QGA_FSFREEZE_HOOK_DEFAULT CONFIG_QEMU_CONFDIR "/fsfreeze-hook"
54 #endif
55 #define QGA_SENTINEL_BYTE 0xFF
56 #define QGA_CONF_DEFAULT CONFIG_QEMU_CONFDIR G_DIR_SEPARATOR_S "qemu-ga.conf"
57
58 static struct {
59 const char *state_dir;
60 const char *pidfile;
61 } dfl_pathnames;
62
63 typedef struct GAPersistentState {
64 #define QGA_PSTATE_DEFAULT_FD_COUNTER 1000
65 int64_t fd_counter;
66 } GAPersistentState;
67
68 struct GAState {
69 JSONMessageParser parser;
70 GMainLoop *main_loop;
71 GAChannel *channel;
72 bool virtio; /* fastpath to check for virtio to deal with poll() quirks */
73 GACommandState *command_state;
74 GLogLevelFlags log_level;
75 FILE *log_file;
76 bool logging_enabled;
77 #ifdef _WIN32
78 GAService service;
79 #endif
80 bool delimit_response;
81 bool frozen;
82 GList *blacklist;
83 char *state_filepath_isfrozen;
84 struct {
85 const char *log_filepath;
86 const char *pid_filepath;
87 } deferred_options;
88 #ifdef CONFIG_FSFREEZE
89 const char *fsfreeze_hook;
90 #endif
91 gchar *pstate_filepath;
92 GAPersistentState pstate;
93 };
94
95 struct GAState *ga_state;
96
97 /* commands that are safe to issue while filesystems are frozen */
98 static const char *ga_freeze_whitelist[] = {
99 "guest-ping",
100 "guest-info",
101 "guest-sync",
102 "guest-sync-delimited",
103 "guest-fsfreeze-status",
104 "guest-fsfreeze-thaw",
105 NULL
106 };
107
108 #ifdef _WIN32
109 DWORD WINAPI service_ctrl_handler(DWORD ctrl, DWORD type, LPVOID data,
110 LPVOID ctx);
111 VOID WINAPI service_main(DWORD argc, TCHAR *argv[]);
112 #endif
113
114 static void
115 init_dfl_pathnames(void)
116 {
117 g_assert(dfl_pathnames.state_dir == NULL);
118 g_assert(dfl_pathnames.pidfile == NULL);
119 dfl_pathnames.state_dir = qemu_get_local_state_pathname(
120 QGA_STATE_RELATIVE_DIR);
121 dfl_pathnames.pidfile = qemu_get_local_state_pathname(
122 QGA_STATE_RELATIVE_DIR G_DIR_SEPARATOR_S "qemu-ga.pid");
123 }
124
125 static void quit_handler(int sig)
126 {
127 /* if we're frozen, don't exit unless we're absolutely forced to,
128 * because it's basically impossible for graceful exit to complete
129 * unless all log/pid files are on unfreezable filesystems. there's
130 * also a very likely chance killing the agent before unfreezing
131 * the filesystems is a mistake (or will be viewed as one later).
132 */
133 if (ga_is_frozen(ga_state)) {
134 return;
135 }
136 g_debug("received signal num %d, quitting", sig);
137
138 if (g_main_loop_is_running(ga_state->main_loop)) {
139 g_main_loop_quit(ga_state->main_loop);
140 }
141 }
142
143 #ifndef _WIN32
144 static gboolean register_signal_handlers(void)
145 {
146 struct sigaction sigact;
147 int ret;
148
149 memset(&sigact, 0, sizeof(struct sigaction));
150 sigact.sa_handler = quit_handler;
151
152 ret = sigaction(SIGINT, &sigact, NULL);
153 if (ret == -1) {
154 g_error("error configuring signal handler: %s", strerror(errno));
155 }
156 ret = sigaction(SIGTERM, &sigact, NULL);
157 if (ret == -1) {
158 g_error("error configuring signal handler: %s", strerror(errno));
159 }
160
161 sigact.sa_handler = SIG_IGN;
162 if (sigaction(SIGPIPE, &sigact, NULL) != 0) {
163 g_error("error configuring SIGPIPE signal handler: %s",
164 strerror(errno));
165 }
166
167 return true;
168 }
169
170 /* TODO: use this in place of all post-fork() fclose(std*) callers */
171 void reopen_fd_to_null(int fd)
172 {
173 int nullfd;
174
175 nullfd = open("/dev/null", O_RDWR);
176 if (nullfd < 0) {
177 return;
178 }
179
180 dup2(nullfd, fd);
181
182 if (nullfd != fd) {
183 close(nullfd);
184 }
185 }
186 #endif
187
188 static void usage(const char *cmd)
189 {
190 printf(
191 "Usage: %s [-m <method> -p <path>] [<options>]\n"
192 "QEMU Guest Agent %s\n"
193 "\n"
194 " -m, --method transport method: one of unix-listen, virtio-serial, or\n"
195 " isa-serial (virtio-serial is the default)\n"
196 " -p, --path device/socket path (the default for virtio-serial is:\n"
197 " %s,\n"
198 " the default for isa-serial is:\n"
199 " %s)\n"
200 " -l, --logfile set logfile path, logs to stderr by default\n"
201 " -f, --pidfile specify pidfile (default is %s)\n"
202 #ifdef CONFIG_FSFREEZE
203 " -F, --fsfreeze-hook\n"
204 " enable fsfreeze hook. Accepts an optional argument that\n"
205 " specifies script to run on freeze/thaw. Script will be\n"
206 " called with 'freeze'/'thaw' arguments accordingly.\n"
207 " (default is %s)\n"
208 " If using -F with an argument, do not follow -F with a\n"
209 " space.\n"
210 " (for example: -F/var/run/fsfreezehook.sh)\n"
211 #endif
212 " -t, --statedir specify dir to store state information (absolute paths\n"
213 " only, default is %s)\n"
214 " -v, --verbose log extra debugging information\n"
215 " -V, --version print version information and exit\n"
216 " -d, --daemonize become a daemon\n"
217 #ifdef _WIN32
218 " -s, --service service commands: install, uninstall, vss-install, vss-uninstall\n"
219 #endif
220 " -b, --blacklist comma-separated list of RPCs to disable (no spaces, \"?\"\n"
221 " to list available RPCs)\n"
222 " -D, --dump-conf dump a qemu-ga config file based on current config\n"
223 " options / command-line parameters to stdout\n"
224 " -h, --help display this help and exit\n"
225 "\n"
226 "Report bugs to <mdroth@linux.vnet.ibm.com>\n"
227 , cmd, QEMU_VERSION, QGA_VIRTIO_PATH_DEFAULT, QGA_SERIAL_PATH_DEFAULT,
228 dfl_pathnames.pidfile,
229 #ifdef CONFIG_FSFREEZE
230 QGA_FSFREEZE_HOOK_DEFAULT,
231 #endif
232 dfl_pathnames.state_dir);
233 }
234
235 static const char *ga_log_level_str(GLogLevelFlags level)
236 {
237 switch (level & G_LOG_LEVEL_MASK) {
238 case G_LOG_LEVEL_ERROR:
239 return "error";
240 case G_LOG_LEVEL_CRITICAL:
241 return "critical";
242 case G_LOG_LEVEL_WARNING:
243 return "warning";
244 case G_LOG_LEVEL_MESSAGE:
245 return "message";
246 case G_LOG_LEVEL_INFO:
247 return "info";
248 case G_LOG_LEVEL_DEBUG:
249 return "debug";
250 default:
251 return "user";
252 }
253 }
254
255 bool ga_logging_enabled(GAState *s)
256 {
257 return s->logging_enabled;
258 }
259
260 void ga_disable_logging(GAState *s)
261 {
262 s->logging_enabled = false;
263 }
264
265 void ga_enable_logging(GAState *s)
266 {
267 s->logging_enabled = true;
268 }
269
270 static void ga_log(const gchar *domain, GLogLevelFlags level,
271 const gchar *msg, gpointer opaque)
272 {
273 GAState *s = opaque;
274 GTimeVal time;
275 const char *level_str = ga_log_level_str(level);
276
277 if (!ga_logging_enabled(s)) {
278 return;
279 }
280
281 level &= G_LOG_LEVEL_MASK;
282 #ifndef _WIN32
283 if (g_strcmp0(domain, "syslog") == 0) {
284 syslog(LOG_INFO, "%s: %s", level_str, msg);
285 } else if (level & s->log_level) {
286 #else
287 if (level & s->log_level) {
288 #endif
289 g_get_current_time(&time);
290 fprintf(s->log_file,
291 "%lu.%lu: %s: %s\n", time.tv_sec, time.tv_usec, level_str, msg);
292 fflush(s->log_file);
293 }
294 }
295
296 void ga_set_response_delimited(GAState *s)
297 {
298 s->delimit_response = true;
299 }
300
301 static FILE *ga_open_logfile(const char *logfile)
302 {
303 FILE *f;
304
305 f = fopen(logfile, "a");
306 if (!f) {
307 return NULL;
308 }
309
310 qemu_set_cloexec(fileno(f));
311 return f;
312 }
313
314 #ifndef _WIN32
315 static bool ga_open_pidfile(const char *pidfile)
316 {
317 int pidfd;
318 char pidstr[32];
319
320 pidfd = qemu_open(pidfile, O_CREAT|O_WRONLY, S_IRUSR|S_IWUSR);
321 if (pidfd == -1 || lockf(pidfd, F_TLOCK, 0)) {
322 g_critical("Cannot lock pid file, %s", strerror(errno));
323 if (pidfd != -1) {
324 close(pidfd);
325 }
326 return false;
327 }
328
329 if (ftruncate(pidfd, 0)) {
330 g_critical("Failed to truncate pid file");
331 goto fail;
332 }
333 snprintf(pidstr, sizeof(pidstr), "%d\n", getpid());
334 if (write(pidfd, pidstr, strlen(pidstr)) != strlen(pidstr)) {
335 g_critical("Failed to write pid file");
336 goto fail;
337 }
338
339 /* keep pidfile open & locked forever */
340 return true;
341
342 fail:
343 unlink(pidfile);
344 close(pidfd);
345 return false;
346 }
347 #else /* _WIN32 */
348 static bool ga_open_pidfile(const char *pidfile)
349 {
350 return true;
351 }
352 #endif
353
354 static gint ga_strcmp(gconstpointer str1, gconstpointer str2)
355 {
356 return strcmp(str1, str2);
357 }
358
359 /* disable commands that aren't safe for fsfreeze */
360 static void ga_disable_non_whitelisted(QmpCommand *cmd, void *opaque)
361 {
362 bool whitelisted = false;
363 int i = 0;
364 const char *name = qmp_command_name(cmd);
365
366 while (ga_freeze_whitelist[i] != NULL) {
367 if (strcmp(name, ga_freeze_whitelist[i]) == 0) {
368 whitelisted = true;
369 }
370 i++;
371 }
372 if (!whitelisted) {
373 g_debug("disabling command: %s", name);
374 qmp_disable_command(name);
375 }
376 }
377
378 /* [re-]enable all commands, except those explicitly blacklisted by user */
379 static void ga_enable_non_blacklisted(QmpCommand *cmd, void *opaque)
380 {
381 GList *blacklist = opaque;
382 const char *name = qmp_command_name(cmd);
383
384 if (g_list_find_custom(blacklist, name, ga_strcmp) == NULL &&
385 !qmp_command_is_enabled(cmd)) {
386 g_debug("enabling command: %s", name);
387 qmp_enable_command(name);
388 }
389 }
390
391 static bool ga_create_file(const char *path)
392 {
393 int fd = open(path, O_CREAT | O_WRONLY, S_IWUSR | S_IRUSR);
394 if (fd == -1) {
395 g_warning("unable to open/create file %s: %s", path, strerror(errno));
396 return false;
397 }
398 close(fd);
399 return true;
400 }
401
402 static bool ga_delete_file(const char *path)
403 {
404 int ret = unlink(path);
405 if (ret == -1) {
406 g_warning("unable to delete file: %s: %s", path, strerror(errno));
407 return false;
408 }
409
410 return true;
411 }
412
413 bool ga_is_frozen(GAState *s)
414 {
415 return s->frozen;
416 }
417
418 void ga_set_frozen(GAState *s)
419 {
420 if (ga_is_frozen(s)) {
421 return;
422 }
423 /* disable all non-whitelisted (for frozen state) commands */
424 qmp_for_each_command(ga_disable_non_whitelisted, NULL);
425 g_warning("disabling logging due to filesystem freeze");
426 ga_disable_logging(s);
427 s->frozen = true;
428 if (!ga_create_file(s->state_filepath_isfrozen)) {
429 g_warning("unable to create %s, fsfreeze may not function properly",
430 s->state_filepath_isfrozen);
431 }
432 }
433
434 void ga_unset_frozen(GAState *s)
435 {
436 if (!ga_is_frozen(s)) {
437 return;
438 }
439
440 /* if we delayed creation/opening of pid/log files due to being
441 * in a frozen state at start up, do it now
442 */
443 if (s->deferred_options.log_filepath) {
444 s->log_file = ga_open_logfile(s->deferred_options.log_filepath);
445 if (!s->log_file) {
446 s->log_file = stderr;
447 }
448 s->deferred_options.log_filepath = NULL;
449 }
450 ga_enable_logging(s);
451 g_warning("logging re-enabled due to filesystem unfreeze");
452 if (s->deferred_options.pid_filepath) {
453 if (!ga_open_pidfile(s->deferred_options.pid_filepath)) {
454 g_warning("failed to create/open pid file");
455 }
456 s->deferred_options.pid_filepath = NULL;
457 }
458
459 /* enable all disabled, non-blacklisted commands */
460 qmp_for_each_command(ga_enable_non_blacklisted, s->blacklist);
461 s->frozen = false;
462 if (!ga_delete_file(s->state_filepath_isfrozen)) {
463 g_warning("unable to delete %s, fsfreeze may not function properly",
464 s->state_filepath_isfrozen);
465 }
466 }
467
468 #ifdef CONFIG_FSFREEZE
469 const char *ga_fsfreeze_hook(GAState *s)
470 {
471 return s->fsfreeze_hook;
472 }
473 #endif
474
475 static void become_daemon(const char *pidfile)
476 {
477 #ifndef _WIN32
478 pid_t pid, sid;
479
480 pid = fork();
481 if (pid < 0) {
482 exit(EXIT_FAILURE);
483 }
484 if (pid > 0) {
485 exit(EXIT_SUCCESS);
486 }
487
488 if (pidfile) {
489 if (!ga_open_pidfile(pidfile)) {
490 g_critical("failed to create pidfile");
491 exit(EXIT_FAILURE);
492 }
493 }
494
495 umask(S_IRWXG | S_IRWXO);
496 sid = setsid();
497 if (sid < 0) {
498 goto fail;
499 }
500 if ((chdir("/")) < 0) {
501 goto fail;
502 }
503
504 reopen_fd_to_null(STDIN_FILENO);
505 reopen_fd_to_null(STDOUT_FILENO);
506 reopen_fd_to_null(STDERR_FILENO);
507 return;
508
509 fail:
510 if (pidfile) {
511 unlink(pidfile);
512 }
513 g_critical("failed to daemonize");
514 exit(EXIT_FAILURE);
515 #endif
516 }
517
518 static int send_response(GAState *s, QObject *payload)
519 {
520 const char *buf;
521 QString *payload_qstr, *response_qstr;
522 GIOStatus status;
523
524 g_assert(payload && s->channel);
525
526 payload_qstr = qobject_to_json(payload);
527 if (!payload_qstr) {
528 return -EINVAL;
529 }
530
531 if (s->delimit_response) {
532 s->delimit_response = false;
533 response_qstr = qstring_new();
534 qstring_append_chr(response_qstr, QGA_SENTINEL_BYTE);
535 qstring_append(response_qstr, qstring_get_str(payload_qstr));
536 QDECREF(payload_qstr);
537 } else {
538 response_qstr = payload_qstr;
539 }
540
541 qstring_append_chr(response_qstr, '\n');
542 buf = qstring_get_str(response_qstr);
543 status = ga_channel_write_all(s->channel, buf, strlen(buf));
544 QDECREF(response_qstr);
545 if (status != G_IO_STATUS_NORMAL) {
546 return -EIO;
547 }
548
549 return 0;
550 }
551
552 static void process_command(GAState *s, QDict *req)
553 {
554 QObject *rsp = NULL;
555 int ret;
556
557 g_assert(req);
558 g_debug("processing command");
559 rsp = qmp_dispatch(QOBJECT(req));
560 if (rsp) {
561 ret = send_response(s, rsp);
562 if (ret) {
563 g_warning("error sending response: %s", strerror(ret));
564 }
565 qobject_decref(rsp);
566 }
567 }
568
569 /* handle requests/control events coming in over the channel */
570 static void process_event(JSONMessageParser *parser, GQueue *tokens)
571 {
572 GAState *s = container_of(parser, GAState, parser);
573 QDict *qdict;
574 Error *err = NULL;
575 int ret;
576
577 g_assert(s && parser);
578
579 g_debug("process_event: called");
580 qdict = qobject_to_qdict(json_parser_parse_err(tokens, NULL, &err));
581 if (err || !qdict) {
582 QDECREF(qdict);
583 qdict = qdict_new();
584 if (!err) {
585 g_warning("failed to parse event: unknown error");
586 error_setg(&err, QERR_JSON_PARSING);
587 } else {
588 g_warning("failed to parse event: %s", error_get_pretty(err));
589 }
590 qdict_put_obj(qdict, "error", qmp_build_error_object(err));
591 error_free(err);
592 }
593
594 /* handle host->guest commands */
595 if (qdict_haskey(qdict, "execute")) {
596 process_command(s, qdict);
597 } else {
598 if (!qdict_haskey(qdict, "error")) {
599 QDECREF(qdict);
600 qdict = qdict_new();
601 g_warning("unrecognized payload format");
602 error_setg(&err, QERR_UNSUPPORTED);
603 qdict_put_obj(qdict, "error", qmp_build_error_object(err));
604 error_free(err);
605 }
606 ret = send_response(s, QOBJECT(qdict));
607 if (ret < 0) {
608 g_warning("error sending error response: %s", strerror(-ret));
609 }
610 }
611
612 QDECREF(qdict);
613 }
614
615 /* false return signals GAChannel to close the current client connection */
616 static gboolean channel_event_cb(GIOCondition condition, gpointer data)
617 {
618 GAState *s = data;
619 gchar buf[QGA_READ_COUNT_DEFAULT+1];
620 gsize count;
621 GIOStatus status = ga_channel_read(s->channel, buf, QGA_READ_COUNT_DEFAULT, &count);
622 switch (status) {
623 case G_IO_STATUS_ERROR:
624 g_warning("error reading channel");
625 return false;
626 case G_IO_STATUS_NORMAL:
627 buf[count] = 0;
628 g_debug("read data, count: %d, data: %s", (int)count, buf);
629 json_message_parser_feed(&s->parser, (char *)buf, (int)count);
630 break;
631 case G_IO_STATUS_EOF:
632 g_debug("received EOF");
633 if (!s->virtio) {
634 return false;
635 }
636 /* fall through */
637 case G_IO_STATUS_AGAIN:
638 /* virtio causes us to spin here when no process is attached to
639 * host-side chardev. sleep a bit to mitigate this
640 */
641 if (s->virtio) {
642 usleep(100*1000);
643 }
644 return true;
645 default:
646 g_warning("unknown channel read status, closing");
647 return false;
648 }
649 return true;
650 }
651
652 static gboolean channel_init(GAState *s, const gchar *method, const gchar *path)
653 {
654 GAChannelMethod channel_method;
655
656 if (strcmp(method, "virtio-serial") == 0) {
657 s->virtio = true; /* virtio requires special handling in some cases */
658 channel_method = GA_CHANNEL_VIRTIO_SERIAL;
659 } else if (strcmp(method, "isa-serial") == 0) {
660 channel_method = GA_CHANNEL_ISA_SERIAL;
661 } else if (strcmp(method, "unix-listen") == 0) {
662 channel_method = GA_CHANNEL_UNIX_LISTEN;
663 } else {
664 g_critical("unsupported channel method/type: %s", method);
665 return false;
666 }
667
668 s->channel = ga_channel_new(channel_method, path, channel_event_cb, s);
669 if (!s->channel) {
670 g_critical("failed to create guest agent channel");
671 return false;
672 }
673
674 return true;
675 }
676
677 #ifdef _WIN32
678 DWORD WINAPI service_ctrl_handler(DWORD ctrl, DWORD type, LPVOID data,
679 LPVOID ctx)
680 {
681 DWORD ret = NO_ERROR;
682 GAService *service = &ga_state->service;
683
684 switch (ctrl)
685 {
686 case SERVICE_CONTROL_STOP:
687 case SERVICE_CONTROL_SHUTDOWN:
688 quit_handler(SIGTERM);
689 service->status.dwCurrentState = SERVICE_STOP_PENDING;
690 SetServiceStatus(service->status_handle, &service->status);
691 break;
692
693 default:
694 ret = ERROR_CALL_NOT_IMPLEMENTED;
695 }
696 return ret;
697 }
698
699 VOID WINAPI service_main(DWORD argc, TCHAR *argv[])
700 {
701 GAService *service = &ga_state->service;
702
703 service->status_handle = RegisterServiceCtrlHandlerEx(QGA_SERVICE_NAME,
704 service_ctrl_handler, NULL);
705
706 if (service->status_handle == 0) {
707 g_critical("Failed to register extended requests function!\n");
708 return;
709 }
710
711 service->status.dwServiceType = SERVICE_WIN32;
712 service->status.dwCurrentState = SERVICE_RUNNING;
713 service->status.dwControlsAccepted = SERVICE_ACCEPT_STOP | SERVICE_ACCEPT_SHUTDOWN;
714 service->status.dwWin32ExitCode = NO_ERROR;
715 service->status.dwServiceSpecificExitCode = NO_ERROR;
716 service->status.dwCheckPoint = 0;
717 service->status.dwWaitHint = 0;
718 SetServiceStatus(service->status_handle, &service->status);
719
720 g_main_loop_run(ga_state->main_loop);
721
722 service->status.dwCurrentState = SERVICE_STOPPED;
723 SetServiceStatus(service->status_handle, &service->status);
724 }
725 #endif
726
727 static void set_persistent_state_defaults(GAPersistentState *pstate)
728 {
729 g_assert(pstate);
730 pstate->fd_counter = QGA_PSTATE_DEFAULT_FD_COUNTER;
731 }
732
733 static void persistent_state_from_keyfile(GAPersistentState *pstate,
734 GKeyFile *keyfile)
735 {
736 g_assert(pstate);
737 g_assert(keyfile);
738 /* if any fields are missing, either because the file was tampered with
739 * by agents of chaos, or because the field wasn't present at the time the
740 * file was created, the best we can ever do is start over with the default
741 * values. so load them now, and ignore any errors in accessing key-value
742 * pairs
743 */
744 set_persistent_state_defaults(pstate);
745
746 if (g_key_file_has_key(keyfile, "global", "fd_counter", NULL)) {
747 pstate->fd_counter =
748 g_key_file_get_integer(keyfile, "global", "fd_counter", NULL);
749 }
750 }
751
752 static void persistent_state_to_keyfile(const GAPersistentState *pstate,
753 GKeyFile *keyfile)
754 {
755 g_assert(pstate);
756 g_assert(keyfile);
757
758 g_key_file_set_integer(keyfile, "global", "fd_counter", pstate->fd_counter);
759 }
760
761 static gboolean write_persistent_state(const GAPersistentState *pstate,
762 const gchar *path)
763 {
764 GKeyFile *keyfile = g_key_file_new();
765 GError *gerr = NULL;
766 gboolean ret = true;
767 gchar *data = NULL;
768 gsize data_len;
769
770 g_assert(pstate);
771
772 persistent_state_to_keyfile(pstate, keyfile);
773 data = g_key_file_to_data(keyfile, &data_len, &gerr);
774 if (gerr) {
775 g_critical("failed to convert persistent state to string: %s",
776 gerr->message);
777 ret = false;
778 goto out;
779 }
780
781 g_file_set_contents(path, data, data_len, &gerr);
782 if (gerr) {
783 g_critical("failed to write persistent state to %s: %s",
784 path, gerr->message);
785 ret = false;
786 goto out;
787 }
788
789 out:
790 if (gerr) {
791 g_error_free(gerr);
792 }
793 if (keyfile) {
794 g_key_file_free(keyfile);
795 }
796 g_free(data);
797 return ret;
798 }
799
800 static gboolean read_persistent_state(GAPersistentState *pstate,
801 const gchar *path, gboolean frozen)
802 {
803 GKeyFile *keyfile = NULL;
804 GError *gerr = NULL;
805 struct stat st;
806 gboolean ret = true;
807
808 g_assert(pstate);
809
810 if (stat(path, &st) == -1) {
811 /* it's okay if state file doesn't exist, but any other error
812 * indicates a permissions issue or some other misconfiguration
813 * that we likely won't be able to recover from.
814 */
815 if (errno != ENOENT) {
816 g_critical("unable to access state file at path %s: %s",
817 path, strerror(errno));
818 ret = false;
819 goto out;
820 }
821
822 /* file doesn't exist. initialize state to default values and
823 * attempt to save now. (we could wait till later when we have
824 * modified state we need to commit, but if there's a problem,
825 * such as a missing parent directory, we want to catch it now)
826 *
827 * there is a potential scenario where someone either managed to
828 * update the agent from a version that didn't use a key store
829 * while qemu-ga thought the filesystem was frozen, or
830 * deleted the key store prior to issuing a fsfreeze, prior
831 * to restarting the agent. in this case we go ahead and defer
832 * initial creation till we actually have modified state to
833 * write, otherwise fail to recover from freeze.
834 */
835 set_persistent_state_defaults(pstate);
836 if (!frozen) {
837 ret = write_persistent_state(pstate, path);
838 if (!ret) {
839 g_critical("unable to create state file at path %s", path);
840 ret = false;
841 goto out;
842 }
843 }
844 ret = true;
845 goto out;
846 }
847
848 keyfile = g_key_file_new();
849 g_key_file_load_from_file(keyfile, path, 0, &gerr);
850 if (gerr) {
851 g_critical("error loading persistent state from path: %s, %s",
852 path, gerr->message);
853 ret = false;
854 goto out;
855 }
856
857 persistent_state_from_keyfile(pstate, keyfile);
858
859 out:
860 if (keyfile) {
861 g_key_file_free(keyfile);
862 }
863 if (gerr) {
864 g_error_free(gerr);
865 }
866
867 return ret;
868 }
869
870 int64_t ga_get_fd_handle(GAState *s, Error **errp)
871 {
872 int64_t handle;
873
874 g_assert(s->pstate_filepath);
875 /* we blacklist commands and avoid operations that potentially require
876 * writing to disk when we're in a frozen state. this includes opening
877 * new files, so we should never get here in that situation
878 */
879 g_assert(!ga_is_frozen(s));
880
881 handle = s->pstate.fd_counter++;
882
883 /* This should never happen on a reasonable timeframe, as guest-file-open
884 * would have to be issued 2^63 times */
885 if (s->pstate.fd_counter == INT64_MAX) {
886 abort();
887 }
888
889 if (!write_persistent_state(&s->pstate, s->pstate_filepath)) {
890 error_setg(errp, "failed to commit persistent state to disk");
891 return -1;
892 }
893
894 return handle;
895 }
896
897 static void ga_print_cmd(QmpCommand *cmd, void *opaque)
898 {
899 printf("%s\n", qmp_command_name(cmd));
900 }
901
902 static GList *split_list(const gchar *str, const gchar *delim)
903 {
904 GList *list = NULL;
905 int i;
906 gchar **strv;
907
908 strv = g_strsplit(str, delim, -1);
909 for (i = 0; strv[i]; i++) {
910 list = g_list_prepend(list, strv[i]);
911 }
912 g_free(strv);
913
914 return list;
915 }
916
917 typedef struct GAConfig {
918 char *channel_path;
919 char *method;
920 char *log_filepath;
921 char *pid_filepath;
922 #ifdef CONFIG_FSFREEZE
923 char *fsfreeze_hook;
924 #endif
925 char *state_dir;
926 #ifdef _WIN32
927 const char *service;
928 #endif
929 gchar *bliststr; /* blacklist may point to this string */
930 GList *blacklist;
931 int daemonize;
932 GLogLevelFlags log_level;
933 int dumpconf;
934 } GAConfig;
935
936 static void config_load(GAConfig *config)
937 {
938 GError *gerr = NULL;
939 GKeyFile *keyfile;
940 const char *conf = g_getenv("QGA_CONF") ?: QGA_CONF_DEFAULT;
941
942 /* read system config */
943 keyfile = g_key_file_new();
944 if (!g_key_file_load_from_file(keyfile, conf, 0, &gerr)) {
945 goto end;
946 }
947 if (g_key_file_has_key(keyfile, "general", "daemon", NULL)) {
948 config->daemonize =
949 g_key_file_get_boolean(keyfile, "general", "daemon", &gerr);
950 }
951 if (g_key_file_has_key(keyfile, "general", "method", NULL)) {
952 config->method =
953 g_key_file_get_string(keyfile, "general", "method", &gerr);
954 }
955 if (g_key_file_has_key(keyfile, "general", "path", NULL)) {
956 config->channel_path =
957 g_key_file_get_string(keyfile, "general", "path", &gerr);
958 }
959 if (g_key_file_has_key(keyfile, "general", "logfile", NULL)) {
960 config->log_filepath =
961 g_key_file_get_string(keyfile, "general", "logfile", &gerr);
962 }
963 if (g_key_file_has_key(keyfile, "general", "pidfile", NULL)) {
964 config->pid_filepath =
965 g_key_file_get_string(keyfile, "general", "pidfile", &gerr);
966 }
967 #ifdef CONFIG_FSFREEZE
968 if (g_key_file_has_key(keyfile, "general", "fsfreeze-hook", NULL)) {
969 config->fsfreeze_hook =
970 g_key_file_get_string(keyfile,
971 "general", "fsfreeze-hook", &gerr);
972 }
973 #endif
974 if (g_key_file_has_key(keyfile, "general", "statedir", NULL)) {
975 config->state_dir =
976 g_key_file_get_string(keyfile, "general", "statedir", &gerr);
977 }
978 if (g_key_file_has_key(keyfile, "general", "verbose", NULL) &&
979 g_key_file_get_boolean(keyfile, "general", "verbose", &gerr)) {
980 /* enable all log levels */
981 config->log_level = G_LOG_LEVEL_MASK;
982 }
983 if (g_key_file_has_key(keyfile, "general", "blacklist", NULL)) {
984 config->bliststr =
985 g_key_file_get_string(keyfile, "general", "blacklist", &gerr);
986 config->blacklist = g_list_concat(config->blacklist,
987 split_list(config->bliststr, ","));
988 }
989
990 end:
991 g_key_file_free(keyfile);
992 if (gerr &&
993 !(gerr->domain == G_FILE_ERROR && gerr->code == G_FILE_ERROR_NOENT)) {
994 g_critical("error loading configuration from path: %s, %s",
995 QGA_CONF_DEFAULT, gerr->message);
996 exit(EXIT_FAILURE);
997 }
998 g_clear_error(&gerr);
999 }
1000
1001 static gchar *list_join(GList *list, const gchar separator)
1002 {
1003 GString *str = g_string_new("");
1004
1005 while (list) {
1006 str = g_string_append(str, (gchar *)list->data);
1007 list = g_list_next(list);
1008 if (list) {
1009 str = g_string_append_c(str, separator);
1010 }
1011 }
1012
1013 return g_string_free(str, FALSE);
1014 }
1015
1016 static void config_dump(GAConfig *config)
1017 {
1018 GError *error = NULL;
1019 GKeyFile *keyfile;
1020 gchar *tmp;
1021
1022 keyfile = g_key_file_new();
1023 g_assert(keyfile);
1024
1025 g_key_file_set_boolean(keyfile, "general", "daemon", config->daemonize);
1026 g_key_file_set_string(keyfile, "general", "method", config->method);
1027 g_key_file_set_string(keyfile, "general", "path", config->channel_path);
1028 if (config->log_filepath) {
1029 g_key_file_set_string(keyfile, "general", "logfile",
1030 config->log_filepath);
1031 }
1032 g_key_file_set_string(keyfile, "general", "pidfile", config->pid_filepath);
1033 #ifdef CONFIG_FSFREEZE
1034 if (config->fsfreeze_hook) {
1035 g_key_file_set_string(keyfile, "general", "fsfreeze-hook",
1036 config->fsfreeze_hook);
1037 }
1038 #endif
1039 g_key_file_set_string(keyfile, "general", "statedir", config->state_dir);
1040 g_key_file_set_boolean(keyfile, "general", "verbose",
1041 config->log_level == G_LOG_LEVEL_MASK);
1042 tmp = list_join(config->blacklist, ',');
1043 g_key_file_set_string(keyfile, "general", "blacklist", tmp);
1044 g_free(tmp);
1045
1046 tmp = g_key_file_to_data(keyfile, NULL, &error);
1047 printf("%s", tmp);
1048
1049 g_free(tmp);
1050 g_key_file_free(keyfile);
1051 }
1052
1053 static void config_parse(GAConfig *config, int argc, char **argv)
1054 {
1055 const char *sopt = "hVvdm:p:l:f:F::b:s:t:D";
1056 int opt_ind = 0, ch;
1057 const struct option lopt[] = {
1058 { "help", 0, NULL, 'h' },
1059 { "version", 0, NULL, 'V' },
1060 { "dump-conf", 0, NULL, 'D' },
1061 { "logfile", 1, NULL, 'l' },
1062 { "pidfile", 1, NULL, 'f' },
1063 #ifdef CONFIG_FSFREEZE
1064 { "fsfreeze-hook", 2, NULL, 'F' },
1065 #endif
1066 { "verbose", 0, NULL, 'v' },
1067 { "method", 1, NULL, 'm' },
1068 { "path", 1, NULL, 'p' },
1069 { "daemonize", 0, NULL, 'd' },
1070 { "blacklist", 1, NULL, 'b' },
1071 #ifdef _WIN32
1072 { "service", 1, NULL, 's' },
1073 #endif
1074 { "statedir", 1, NULL, 't' },
1075 { NULL, 0, NULL, 0 }
1076 };
1077
1078 while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
1079 switch (ch) {
1080 case 'm':
1081 g_free(config->method);
1082 config->method = g_strdup(optarg);
1083 break;
1084 case 'p':
1085 g_free(config->channel_path);
1086 config->channel_path = g_strdup(optarg);
1087 break;
1088 case 'l':
1089 g_free(config->log_filepath);
1090 config->log_filepath = g_strdup(optarg);
1091 break;
1092 case 'f':
1093 g_free(config->pid_filepath);
1094 config->pid_filepath = g_strdup(optarg);
1095 break;
1096 #ifdef CONFIG_FSFREEZE
1097 case 'F':
1098 g_free(config->fsfreeze_hook);
1099 config->fsfreeze_hook = g_strdup(optarg ?: QGA_FSFREEZE_HOOK_DEFAULT);
1100 break;
1101 #endif
1102 case 't':
1103 g_free(config->state_dir);
1104 config->state_dir = g_strdup(optarg);
1105 break;
1106 case 'v':
1107 /* enable all log levels */
1108 config->log_level = G_LOG_LEVEL_MASK;
1109 break;
1110 case 'V':
1111 printf("QEMU Guest Agent %s\n", QEMU_VERSION);
1112 exit(EXIT_SUCCESS);
1113 case 'd':
1114 config->daemonize = 1;
1115 break;
1116 case 'D':
1117 config->dumpconf = 1;
1118 break;
1119 case 'b': {
1120 if (is_help_option(optarg)) {
1121 qmp_for_each_command(ga_print_cmd, NULL);
1122 exit(EXIT_SUCCESS);
1123 }
1124 config->blacklist = g_list_concat(config->blacklist,
1125 split_list(optarg, ","));
1126 break;
1127 }
1128 #ifdef _WIN32
1129 case 's':
1130 config->service = optarg;
1131 if (strcmp(config->service, "install") == 0) {
1132 if (ga_install_vss_provider()) {
1133 exit(EXIT_FAILURE);
1134 }
1135 if (ga_install_service(config->channel_path,
1136 config->log_filepath, config->state_dir)) {
1137 exit(EXIT_FAILURE);
1138 }
1139 exit(EXIT_SUCCESS);
1140 } else if (strcmp(config->service, "uninstall") == 0) {
1141 ga_uninstall_vss_provider();
1142 exit(ga_uninstall_service());
1143 } else if (strcmp(config->service, "vss-install") == 0) {
1144 if (ga_install_vss_provider()) {
1145 exit(EXIT_FAILURE);
1146 }
1147 exit(EXIT_SUCCESS);
1148 } else if (strcmp(config->service, "vss-uninstall") == 0) {
1149 ga_uninstall_vss_provider();
1150 exit(EXIT_SUCCESS);
1151 } else {
1152 printf("Unknown service command.\n");
1153 exit(EXIT_FAILURE);
1154 }
1155 break;
1156 #endif
1157 case 'h':
1158 usage(argv[0]);
1159 exit(EXIT_SUCCESS);
1160 case '?':
1161 g_print("Unknown option, try '%s --help' for more information.\n",
1162 argv[0]);
1163 exit(EXIT_FAILURE);
1164 }
1165 }
1166 }
1167
1168 static void config_free(GAConfig *config)
1169 {
1170 g_free(config->method);
1171 g_free(config->log_filepath);
1172 g_free(config->pid_filepath);
1173 g_free(config->state_dir);
1174 g_free(config->channel_path);
1175 g_free(config->bliststr);
1176 #ifdef CONFIG_FSFREEZE
1177 g_free(config->fsfreeze_hook);
1178 #endif
1179 g_free(config);
1180 }
1181
1182 static bool check_is_frozen(GAState *s)
1183 {
1184 #ifndef _WIN32
1185 /* check if a previous instance of qemu-ga exited with filesystems' state
1186 * marked as frozen. this could be a stale value (a non-qemu-ga process
1187 * or reboot may have since unfrozen them), but better to require an
1188 * uneeded unfreeze than to risk hanging on start-up
1189 */
1190 struct stat st;
1191 if (stat(s->state_filepath_isfrozen, &st) == -1) {
1192 /* it's okay if the file doesn't exist, but if we can't access for
1193 * some other reason, such as permissions, there's a configuration
1194 * that needs to be addressed. so just bail now before we get into
1195 * more trouble later
1196 */
1197 if (errno != ENOENT) {
1198 g_critical("unable to access state file at path %s: %s",
1199 s->state_filepath_isfrozen, strerror(errno));
1200 return EXIT_FAILURE;
1201 }
1202 } else {
1203 g_warning("previous instance appears to have exited with frozen"
1204 " filesystems. deferring logging/pidfile creation and"
1205 " disabling non-fsfreeze-safe commands until"
1206 " guest-fsfreeze-thaw is issued, or filesystems are"
1207 " manually unfrozen and the file %s is removed",
1208 s->state_filepath_isfrozen);
1209 return true;
1210 }
1211 #endif
1212 return false;
1213 }
1214
1215 static int run_agent(GAState *s, GAConfig *config)
1216 {
1217 ga_state = s;
1218
1219 g_log_set_default_handler(ga_log, s);
1220 g_log_set_fatal_mask(NULL, G_LOG_LEVEL_ERROR);
1221 ga_enable_logging(s);
1222
1223 #ifdef _WIN32
1224 /* On win32 the state directory is application specific (be it the default
1225 * or a user override). We got past the command line parsing; let's create
1226 * the directory (with any intermediate directories). If we run into an
1227 * error later on, we won't try to clean up the directory, it is considered
1228 * persistent.
1229 */
1230 if (g_mkdir_with_parents(config->state_dir, S_IRWXU) == -1) {
1231 g_critical("unable to create (an ancestor of) the state directory"
1232 " '%s': %s", config->state_dir, strerror(errno));
1233 return EXIT_FAILURE;
1234 }
1235 #endif
1236
1237 if (ga_is_frozen(s)) {
1238 if (config->daemonize) {
1239 /* delay opening/locking of pidfile till filesystems are unfrozen */
1240 s->deferred_options.pid_filepath = config->pid_filepath;
1241 become_daemon(NULL);
1242 }
1243 if (config->log_filepath) {
1244 /* delay opening the log file till filesystems are unfrozen */
1245 s->deferred_options.log_filepath = config->log_filepath;
1246 }
1247 ga_disable_logging(s);
1248 qmp_for_each_command(ga_disable_non_whitelisted, NULL);
1249 } else {
1250 if (config->daemonize) {
1251 become_daemon(config->pid_filepath);
1252 }
1253 if (config->log_filepath) {
1254 FILE *log_file = ga_open_logfile(config->log_filepath);
1255 if (!log_file) {
1256 g_critical("unable to open specified log file: %s",
1257 strerror(errno));
1258 return EXIT_FAILURE;
1259 }
1260 s->log_file = log_file;
1261 }
1262 }
1263
1264 /* load persistent state from disk */
1265 if (!read_persistent_state(&s->pstate,
1266 s->pstate_filepath,
1267 ga_is_frozen(s))) {
1268 g_critical("failed to load persistent state");
1269 return EXIT_FAILURE;
1270 }
1271
1272 config->blacklist = ga_command_blacklist_init(config->blacklist);
1273 if (config->blacklist) {
1274 GList *l = config->blacklist;
1275 s->blacklist = config->blacklist;
1276 do {
1277 g_debug("disabling command: %s", (char *)l->data);
1278 qmp_disable_command(l->data);
1279 l = g_list_next(l);
1280 } while (l);
1281 }
1282 s->command_state = ga_command_state_new();
1283 ga_command_state_init(s, s->command_state);
1284 ga_command_state_init_all(s->command_state);
1285 json_message_parser_init(&s->parser, process_event);
1286 ga_state = s;
1287 #ifndef _WIN32
1288 if (!register_signal_handlers()) {
1289 g_critical("failed to register signal handlers");
1290 return EXIT_FAILURE;
1291 }
1292 #endif
1293
1294 s->main_loop = g_main_loop_new(NULL, false);
1295 if (!channel_init(ga_state, config->method, config->channel_path)) {
1296 g_critical("failed to initialize guest agent channel");
1297 return EXIT_FAILURE;
1298 }
1299 #ifndef _WIN32
1300 g_main_loop_run(ga_state->main_loop);
1301 #else
1302 if (config->daemonize) {
1303 SERVICE_TABLE_ENTRY service_table[] = {
1304 { (char *)QGA_SERVICE_NAME, service_main }, { NULL, NULL } };
1305 StartServiceCtrlDispatcher(service_table);
1306 } else {
1307 g_main_loop_run(ga_state->main_loop);
1308 }
1309 #endif
1310
1311 return EXIT_SUCCESS;
1312 }
1313
1314 static void free_blacklist_entry(gpointer entry, gpointer unused)
1315 {
1316 g_free(entry);
1317 }
1318
1319 int main(int argc, char **argv)
1320 {
1321 int ret = EXIT_SUCCESS;
1322 GAState *s = g_new0(GAState, 1);
1323 GAConfig *config = g_new0(GAConfig, 1);
1324
1325 config->log_level = G_LOG_LEVEL_ERROR | G_LOG_LEVEL_CRITICAL;
1326
1327 module_call_init(MODULE_INIT_QAPI);
1328
1329 init_dfl_pathnames();
1330 config_load(config);
1331 config_parse(config, argc, argv);
1332
1333 if (config->pid_filepath == NULL) {
1334 config->pid_filepath = g_strdup(dfl_pathnames.pidfile);
1335 }
1336
1337 if (config->state_dir == NULL) {
1338 config->state_dir = g_strdup(dfl_pathnames.state_dir);
1339 }
1340
1341 if (config->method == NULL) {
1342 config->method = g_strdup("virtio-serial");
1343 }
1344
1345 if (config->channel_path == NULL) {
1346 if (strcmp(config->method, "virtio-serial") == 0) {
1347 /* try the default path for the virtio-serial port */
1348 config->channel_path = g_strdup(QGA_VIRTIO_PATH_DEFAULT);
1349 } else if (strcmp(config->method, "isa-serial") == 0) {
1350 /* try the default path for the serial port - COM1 */
1351 config->channel_path = g_strdup(QGA_SERIAL_PATH_DEFAULT);
1352 } else {
1353 g_critical("must specify a path for this channel");
1354 ret = EXIT_FAILURE;
1355 goto end;
1356 }
1357 }
1358
1359 s->log_level = config->log_level;
1360 s->log_file = stderr;
1361 #ifdef CONFIG_FSFREEZE
1362 s->fsfreeze_hook = config->fsfreeze_hook;
1363 #endif
1364 s->pstate_filepath = g_strdup_printf("%s/qga.state", config->state_dir);
1365 s->state_filepath_isfrozen = g_strdup_printf("%s/qga.state.isfrozen",
1366 config->state_dir);
1367 s->frozen = check_is_frozen(s);
1368
1369 if (config->dumpconf) {
1370 config_dump(config);
1371 goto end;
1372 }
1373
1374 ret = run_agent(s, config);
1375
1376 end:
1377 if (s->command_state) {
1378 ga_command_state_cleanup_all(s->command_state);
1379 }
1380 if (s->channel) {
1381 ga_channel_free(s->channel);
1382 }
1383 g_list_foreach(config->blacklist, free_blacklist_entry, NULL);
1384 g_free(s->pstate_filepath);
1385 g_free(s->state_filepath_isfrozen);
1386
1387 if (config->daemonize) {
1388 unlink(config->pid_filepath);
1389 }
1390
1391 config_free(config);
1392
1393 return ret;
1394 }