qga: set umask 0077 when daemonizing (CVE-2013-2007)
[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 <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(S_IRWXG | S_IRWXO);
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
893 /* This should never happen on a reasonable timeframe, as guest-file-open
894 * would have to be issued 2^63 times */
895 if (s->pstate.fd_counter == INT64_MAX) {
896 abort();
897 }
898
899 if (!write_persistent_state(&s->pstate, s->pstate_filepath)) {
900 error_setg(errp, "failed to commit persistent state to disk");
901 }
902
903 return handle;
904 }
905
906 int main(int argc, char **argv)
907 {
908 const char *sopt = "hVvdm:p:l:f:F::b:s:t:";
909 const char *method = NULL, *path = NULL;
910 const char *log_filepath = NULL;
911 const char *pid_filepath = QGA_PIDFILE_DEFAULT;
912 #ifdef CONFIG_FSFREEZE
913 const char *fsfreeze_hook = NULL;
914 #endif
915 const char *state_dir = QGA_STATEDIR_DEFAULT;
916 #ifdef _WIN32
917 const char *service = NULL;
918 #endif
919 const struct option lopt[] = {
920 { "help", 0, NULL, 'h' },
921 { "version", 0, NULL, 'V' },
922 { "logfile", 1, NULL, 'l' },
923 { "pidfile", 1, NULL, 'f' },
924 #ifdef CONFIG_FSFREEZE
925 { "fsfreeze-hook", 2, NULL, 'F' },
926 #endif
927 { "verbose", 0, NULL, 'v' },
928 { "method", 1, NULL, 'm' },
929 { "path", 1, NULL, 'p' },
930 { "daemonize", 0, NULL, 'd' },
931 { "blacklist", 1, NULL, 'b' },
932 #ifdef _WIN32
933 { "service", 1, NULL, 's' },
934 #endif
935 { "statedir", 1, NULL, 't' },
936 { NULL, 0, NULL, 0 }
937 };
938 int opt_ind = 0, ch, daemonize = 0, i, j, len;
939 GLogLevelFlags log_level = G_LOG_LEVEL_ERROR | G_LOG_LEVEL_CRITICAL;
940 GList *blacklist = NULL;
941 GAState *s;
942
943 module_call_init(MODULE_INIT_QAPI);
944
945 while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
946 switch (ch) {
947 case 'm':
948 method = optarg;
949 break;
950 case 'p':
951 path = optarg;
952 break;
953 case 'l':
954 log_filepath = optarg;
955 break;
956 case 'f':
957 pid_filepath = optarg;
958 break;
959 #ifdef CONFIG_FSFREEZE
960 case 'F':
961 fsfreeze_hook = optarg ? optarg : QGA_FSFREEZE_HOOK_DEFAULT;
962 break;
963 #endif
964 case 't':
965 state_dir = optarg;
966 break;
967 case 'v':
968 /* enable all log levels */
969 log_level = G_LOG_LEVEL_MASK;
970 break;
971 case 'V':
972 printf("QEMU Guest Agent %s\n", QEMU_VERSION);
973 return 0;
974 case 'd':
975 daemonize = 1;
976 break;
977 case 'b': {
978 char **list_head, **list;
979 if (is_help_option(optarg)) {
980 list_head = list = qmp_get_command_list();
981 while (*list != NULL) {
982 printf("%s\n", *list);
983 g_free(*list);
984 list++;
985 }
986 g_free(list_head);
987 return 0;
988 }
989 for (j = 0, i = 0, len = strlen(optarg); i < len; i++) {
990 if (optarg[i] == ',') {
991 optarg[i] = 0;
992 blacklist = g_list_append(blacklist, &optarg[j]);
993 j = i + 1;
994 }
995 }
996 if (j < i) {
997 blacklist = g_list_append(blacklist, &optarg[j]);
998 }
999 break;
1000 }
1001 #ifdef _WIN32
1002 case 's':
1003 service = optarg;
1004 if (strcmp(service, "install") == 0) {
1005 return ga_install_service(path, log_filepath);
1006 } else if (strcmp(service, "uninstall") == 0) {
1007 return ga_uninstall_service();
1008 } else {
1009 printf("Unknown service command.\n");
1010 return EXIT_FAILURE;
1011 }
1012 break;
1013 #endif
1014 case 'h':
1015 usage(argv[0]);
1016 return 0;
1017 case '?':
1018 g_print("Unknown option, try '%s --help' for more information.\n",
1019 argv[0]);
1020 return EXIT_FAILURE;
1021 }
1022 }
1023
1024 s = g_malloc0(sizeof(GAState));
1025 s->log_level = log_level;
1026 s->log_file = stderr;
1027 #ifdef CONFIG_FSFREEZE
1028 s->fsfreeze_hook = fsfreeze_hook;
1029 #endif
1030 g_log_set_default_handler(ga_log, s);
1031 g_log_set_fatal_mask(NULL, G_LOG_LEVEL_ERROR);
1032 ga_enable_logging(s);
1033 s->state_filepath_isfrozen = g_strdup_printf("%s/qga.state.isfrozen",
1034 state_dir);
1035 s->pstate_filepath = g_strdup_printf("%s/qga.state", state_dir);
1036 s->frozen = false;
1037
1038 #ifndef _WIN32
1039 /* check if a previous instance of qemu-ga exited with filesystems' state
1040 * marked as frozen. this could be a stale value (a non-qemu-ga process
1041 * or reboot may have since unfrozen them), but better to require an
1042 * uneeded unfreeze than to risk hanging on start-up
1043 */
1044 struct stat st;
1045 if (stat(s->state_filepath_isfrozen, &st) == -1) {
1046 /* it's okay if the file doesn't exist, but if we can't access for
1047 * some other reason, such as permissions, there's a configuration
1048 * that needs to be addressed. so just bail now before we get into
1049 * more trouble later
1050 */
1051 if (errno != ENOENT) {
1052 g_critical("unable to access state file at path %s: %s",
1053 s->state_filepath_isfrozen, strerror(errno));
1054 return EXIT_FAILURE;
1055 }
1056 } else {
1057 g_warning("previous instance appears to have exited with frozen"
1058 " filesystems. deferring logging/pidfile creation and"
1059 " disabling non-fsfreeze-safe commands until"
1060 " guest-fsfreeze-thaw is issued, or filesystems are"
1061 " manually unfrozen and the file %s is removed",
1062 s->state_filepath_isfrozen);
1063 s->frozen = true;
1064 }
1065 #endif
1066
1067 if (ga_is_frozen(s)) {
1068 if (daemonize) {
1069 /* delay opening/locking of pidfile till filesystem are unfrozen */
1070 s->deferred_options.pid_filepath = pid_filepath;
1071 become_daemon(NULL);
1072 }
1073 if (log_filepath) {
1074 /* delay opening the log file till filesystems are unfrozen */
1075 s->deferred_options.log_filepath = log_filepath;
1076 }
1077 ga_disable_logging(s);
1078 ga_disable_non_whitelisted();
1079 } else {
1080 if (daemonize) {
1081 become_daemon(pid_filepath);
1082 }
1083 if (log_filepath) {
1084 FILE *log_file = ga_open_logfile(log_filepath);
1085 if (!log_file) {
1086 g_critical("unable to open specified log file: %s",
1087 strerror(errno));
1088 goto out_bad;
1089 }
1090 s->log_file = log_file;
1091 }
1092 }
1093
1094 /* load persistent state from disk */
1095 if (!read_persistent_state(&s->pstate,
1096 s->pstate_filepath,
1097 ga_is_frozen(s))) {
1098 g_critical("failed to load persistent state");
1099 goto out_bad;
1100 }
1101
1102 if (blacklist) {
1103 s->blacklist = blacklist;
1104 do {
1105 g_debug("disabling command: %s", (char *)blacklist->data);
1106 qmp_disable_command(blacklist->data);
1107 blacklist = g_list_next(blacklist);
1108 } while (blacklist);
1109 }
1110 s->command_state = ga_command_state_new();
1111 ga_command_state_init(s, s->command_state);
1112 ga_command_state_init_all(s->command_state);
1113 json_message_parser_init(&s->parser, process_event);
1114 ga_state = s;
1115 #ifndef _WIN32
1116 if (!register_signal_handlers()) {
1117 g_critical("failed to register signal handlers");
1118 goto out_bad;
1119 }
1120 #endif
1121
1122 s->main_loop = g_main_loop_new(NULL, false);
1123 if (!channel_init(ga_state, method, path)) {
1124 g_critical("failed to initialize guest agent channel");
1125 goto out_bad;
1126 }
1127 #ifndef _WIN32
1128 g_main_loop_run(ga_state->main_loop);
1129 #else
1130 if (daemonize) {
1131 SERVICE_TABLE_ENTRY service_table[] = {
1132 { (char *)QGA_SERVICE_NAME, service_main }, { NULL, NULL } };
1133 StartServiceCtrlDispatcher(service_table);
1134 } else {
1135 g_main_loop_run(ga_state->main_loop);
1136 }
1137 #endif
1138
1139 ga_command_state_cleanup_all(ga_state->command_state);
1140 ga_channel_free(ga_state->channel);
1141
1142 if (daemonize) {
1143 unlink(pid_filepath);
1144 }
1145 return 0;
1146
1147 out_bad:
1148 if (daemonize) {
1149 unlink(pid_filepath);
1150 }
1151 return EXIT_FAILURE;
1152 }