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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 #define QGA_CONF_DEFAULT CONFIG_QEMU_CONFDIR G_DIR_SEPARATOR_S "qemu-ga.conf"
60
61 static struct {
62 const char *state_dir;
63 const char *pidfile;
64 } dfl_pathnames;
65
66 typedef struct GAPersistentState {
67 #define QGA_PSTATE_DEFAULT_FD_COUNTER 1000
68 int64_t fd_counter;
69 } GAPersistentState;
70
71 struct GAState {
72 JSONMessageParser parser;
73 GMainLoop *main_loop;
74 GAChannel *channel;
75 bool virtio; /* fastpath to check for virtio to deal with poll() quirks */
76 GACommandState *command_state;
77 GLogLevelFlags log_level;
78 FILE *log_file;
79 bool logging_enabled;
80 #ifdef _WIN32
81 GAService service;
82 #endif
83 bool delimit_response;
84 bool frozen;
85 GList *blacklist;
86 char *state_filepath_isfrozen;
87 struct {
88 const char *log_filepath;
89 const char *pid_filepath;
90 } deferred_options;
91 #ifdef CONFIG_FSFREEZE
92 const char *fsfreeze_hook;
93 #endif
94 gchar *pstate_filepath;
95 GAPersistentState pstate;
96 };
97
98 struct GAState *ga_state;
99
100 /* commands that are safe to issue while filesystems are frozen */
101 static const char *ga_freeze_whitelist[] = {
102 "guest-ping",
103 "guest-info",
104 "guest-sync",
105 "guest-sync-delimited",
106 "guest-fsfreeze-status",
107 "guest-fsfreeze-thaw",
108 NULL
109 };
110
111 #ifdef _WIN32
112 DWORD WINAPI service_ctrl_handler(DWORD ctrl, DWORD type, LPVOID data,
113 LPVOID ctx);
114 VOID WINAPI service_main(DWORD argc, TCHAR *argv[]);
115 #endif
116
117 static void
118 init_dfl_pathnames(void)
119 {
120 g_assert(dfl_pathnames.state_dir == NULL);
121 g_assert(dfl_pathnames.pidfile == NULL);
122 dfl_pathnames.state_dir = qemu_get_local_state_pathname(
123 QGA_STATE_RELATIVE_DIR);
124 dfl_pathnames.pidfile = qemu_get_local_state_pathname(
125 QGA_STATE_RELATIVE_DIR G_DIR_SEPARATOR_S "qemu-ga.pid");
126 }
127
128 static void quit_handler(int sig)
129 {
130 /* if we're frozen, don't exit unless we're absolutely forced to,
131 * because it's basically impossible for graceful exit to complete
132 * unless all log/pid files are on unfreezable filesystems. there's
133 * also a very likely chance killing the agent before unfreezing
134 * the filesystems is a mistake (or will be viewed as one later).
135 */
136 if (ga_is_frozen(ga_state)) {
137 return;
138 }
139 g_debug("received signal num %d, quitting", sig);
140
141 if (g_main_loop_is_running(ga_state->main_loop)) {
142 g_main_loop_quit(ga_state->main_loop);
143 }
144 }
145
146 #ifndef _WIN32
147 static gboolean register_signal_handlers(void)
148 {
149 struct sigaction sigact;
150 int ret;
151
152 memset(&sigact, 0, sizeof(struct sigaction));
153 sigact.sa_handler = quit_handler;
154
155 ret = sigaction(SIGINT, &sigact, NULL);
156 if (ret == -1) {
157 g_error("error configuring signal handler: %s", strerror(errno));
158 }
159 ret = sigaction(SIGTERM, &sigact, NULL);
160 if (ret == -1) {
161 g_error("error configuring signal handler: %s", strerror(errno));
162 }
163
164 return true;
165 }
166
167 /* TODO: use this in place of all post-fork() fclose(std*) callers */
168 void reopen_fd_to_null(int fd)
169 {
170 int nullfd;
171
172 nullfd = open("/dev/null", O_RDWR);
173 if (nullfd < 0) {
174 return;
175 }
176
177 dup2(nullfd, fd);
178
179 if (nullfd != fd) {
180 close(nullfd);
181 }
182 }
183 #endif
184
185 static void usage(const char *cmd)
186 {
187 printf(
188 "Usage: %s [-m <method> -p <path>] [<options>]\n"
189 "QEMU Guest Agent %s\n"
190 "\n"
191 " -m, --method transport method: one of unix-listen, virtio-serial, or\n"
192 " isa-serial (virtio-serial is the default)\n"
193 " -p, --path device/socket path (the default for virtio-serial is:\n"
194 " %s,\n"
195 " the default for isa-serial is:\n"
196 " %s)\n"
197 " -l, --logfile set logfile path, logs to stderr by default\n"
198 " -f, --pidfile specify pidfile (default is %s)\n"
199 #ifdef CONFIG_FSFREEZE
200 " -F, --fsfreeze-hook\n"
201 " enable fsfreeze hook. Accepts an optional argument that\n"
202 " specifies script to run on freeze/thaw. Script will be\n"
203 " called with 'freeze'/'thaw' arguments accordingly.\n"
204 " (default is %s)\n"
205 " If using -F with an argument, do not follow -F with a\n"
206 " space.\n"
207 " (for example: -F/var/run/fsfreezehook.sh)\n"
208 #endif
209 " -t, --statedir specify dir to store state information (absolute paths\n"
210 " only, default is %s)\n"
211 " -v, --verbose log extra debugging information\n"
212 " -V, --version print version information and exit\n"
213 " -d, --daemonize become a daemon\n"
214 #ifdef _WIN32
215 " -s, --service service commands: install, uninstall, vss-install, vss-uninstall\n"
216 #endif
217 " -b, --blacklist comma-separated list of RPCs to disable (no spaces, \"?\"\n"
218 " to list available RPCs)\n"
219 " -D, --dump-conf dump a qemu-ga config file based on current config\n"
220 " options / command-line parameters to stdout\n"
221 " -h, --help display this help and exit\n"
222 "\n"
223 "Report bugs to <mdroth@linux.vnet.ibm.com>\n"
224 , cmd, QEMU_VERSION, QGA_VIRTIO_PATH_DEFAULT, QGA_SERIAL_PATH_DEFAULT,
225 dfl_pathnames.pidfile,
226 #ifdef CONFIG_FSFREEZE
227 QGA_FSFREEZE_HOOK_DEFAULT,
228 #endif
229 dfl_pathnames.state_dir);
230 }
231
232 static const char *ga_log_level_str(GLogLevelFlags level)
233 {
234 switch (level & G_LOG_LEVEL_MASK) {
235 case G_LOG_LEVEL_ERROR:
236 return "error";
237 case G_LOG_LEVEL_CRITICAL:
238 return "critical";
239 case G_LOG_LEVEL_WARNING:
240 return "warning";
241 case G_LOG_LEVEL_MESSAGE:
242 return "message";
243 case G_LOG_LEVEL_INFO:
244 return "info";
245 case G_LOG_LEVEL_DEBUG:
246 return "debug";
247 default:
248 return "user";
249 }
250 }
251
252 bool ga_logging_enabled(GAState *s)
253 {
254 return s->logging_enabled;
255 }
256
257 void ga_disable_logging(GAState *s)
258 {
259 s->logging_enabled = false;
260 }
261
262 void ga_enable_logging(GAState *s)
263 {
264 s->logging_enabled = true;
265 }
266
267 static void ga_log(const gchar *domain, GLogLevelFlags level,
268 const gchar *msg, gpointer opaque)
269 {
270 GAState *s = opaque;
271 GTimeVal time;
272 const char *level_str = ga_log_level_str(level);
273
274 if (!ga_logging_enabled(s)) {
275 return;
276 }
277
278 level &= G_LOG_LEVEL_MASK;
279 #ifndef _WIN32
280 if (g_strcmp0(domain, "syslog") == 0) {
281 syslog(LOG_INFO, "%s: %s", level_str, msg);
282 } else if (level & s->log_level) {
283 #else
284 if (level & s->log_level) {
285 #endif
286 g_get_current_time(&time);
287 fprintf(s->log_file,
288 "%lu.%lu: %s: %s\n", time.tv_sec, time.tv_usec, level_str, msg);
289 fflush(s->log_file);
290 }
291 }
292
293 void ga_set_response_delimited(GAState *s)
294 {
295 s->delimit_response = true;
296 }
297
298 static FILE *ga_open_logfile(const char *logfile)
299 {
300 FILE *f;
301
302 f = fopen(logfile, "a");
303 if (!f) {
304 return NULL;
305 }
306
307 qemu_set_cloexec(fileno(f));
308 return f;
309 }
310
311 #ifndef _WIN32
312 static bool ga_open_pidfile(const char *pidfile)
313 {
314 int pidfd;
315 char pidstr[32];
316
317 pidfd = qemu_open(pidfile, O_CREAT|O_WRONLY, S_IRUSR|S_IWUSR);
318 if (pidfd == -1 || lockf(pidfd, F_TLOCK, 0)) {
319 g_critical("Cannot lock pid file, %s", strerror(errno));
320 if (pidfd != -1) {
321 close(pidfd);
322 }
323 return false;
324 }
325
326 if (ftruncate(pidfd, 0)) {
327 g_critical("Failed to truncate pid file");
328 goto fail;
329 }
330 snprintf(pidstr, sizeof(pidstr), "%d\n", getpid());
331 if (write(pidfd, pidstr, strlen(pidstr)) != strlen(pidstr)) {
332 g_critical("Failed to write pid file");
333 goto fail;
334 }
335
336 /* keep pidfile open & locked forever */
337 return true;
338
339 fail:
340 unlink(pidfile);
341 close(pidfd);
342 return false;
343 }
344 #else /* _WIN32 */
345 static bool ga_open_pidfile(const char *pidfile)
346 {
347 return true;
348 }
349 #endif
350
351 static gint ga_strcmp(gconstpointer str1, gconstpointer str2)
352 {
353 return strcmp(str1, str2);
354 }
355
356 /* disable commands that aren't safe for fsfreeze */
357 static void ga_disable_non_whitelisted(QmpCommand *cmd, void *opaque)
358 {
359 bool whitelisted = false;
360 int i = 0;
361 const char *name = qmp_command_name(cmd);
362
363 while (ga_freeze_whitelist[i] != NULL) {
364 if (strcmp(name, ga_freeze_whitelist[i]) == 0) {
365 whitelisted = true;
366 }
367 i++;
368 }
369 if (!whitelisted) {
370 g_debug("disabling command: %s", name);
371 qmp_disable_command(name);
372 }
373 }
374
375 /* [re-]enable all commands, except those explicitly blacklisted by user */
376 static void ga_enable_non_blacklisted(QmpCommand *cmd, void *opaque)
377 {
378 GList *blacklist = opaque;
379 const char *name = qmp_command_name(cmd);
380
381 if (g_list_find_custom(blacklist, name, ga_strcmp) == NULL &&
382 !qmp_command_is_enabled(cmd)) {
383 g_debug("enabling command: %s", name);
384 qmp_enable_command(name);
385 }
386 }
387
388 static bool ga_create_file(const char *path)
389 {
390 int fd = open(path, O_CREAT | O_WRONLY, S_IWUSR | S_IRUSR);
391 if (fd == -1) {
392 g_warning("unable to open/create file %s: %s", path, strerror(errno));
393 return false;
394 }
395 close(fd);
396 return true;
397 }
398
399 static bool ga_delete_file(const char *path)
400 {
401 int ret = unlink(path);
402 if (ret == -1) {
403 g_warning("unable to delete file: %s: %s", path, strerror(errno));
404 return false;
405 }
406
407 return true;
408 }
409
410 bool ga_is_frozen(GAState *s)
411 {
412 return s->frozen;
413 }
414
415 void ga_set_frozen(GAState *s)
416 {
417 if (ga_is_frozen(s)) {
418 return;
419 }
420 /* disable all non-whitelisted (for frozen state) commands */
421 qmp_for_each_command(ga_disable_non_whitelisted, NULL);
422 g_warning("disabling logging due to filesystem freeze");
423 ga_disable_logging(s);
424 s->frozen = true;
425 if (!ga_create_file(s->state_filepath_isfrozen)) {
426 g_warning("unable to create %s, fsfreeze may not function properly",
427 s->state_filepath_isfrozen);
428 }
429 }
430
431 void ga_unset_frozen(GAState *s)
432 {
433 if (!ga_is_frozen(s)) {
434 return;
435 }
436
437 /* if we delayed creation/opening of pid/log files due to being
438 * in a frozen state at start up, do it now
439 */
440 if (s->deferred_options.log_filepath) {
441 s->log_file = ga_open_logfile(s->deferred_options.log_filepath);
442 if (!s->log_file) {
443 s->log_file = stderr;
444 }
445 s->deferred_options.log_filepath = NULL;
446 }
447 ga_enable_logging(s);
448 g_warning("logging re-enabled due to filesystem unfreeze");
449 if (s->deferred_options.pid_filepath) {
450 if (!ga_open_pidfile(s->deferred_options.pid_filepath)) {
451 g_warning("failed to create/open pid file");
452 }
453 s->deferred_options.pid_filepath = NULL;
454 }
455
456 /* enable all disabled, non-blacklisted commands */
457 qmp_for_each_command(ga_enable_non_blacklisted, s->blacklist);
458 s->frozen = false;
459 if (!ga_delete_file(s->state_filepath_isfrozen)) {
460 g_warning("unable to delete %s, fsfreeze may not function properly",
461 s->state_filepath_isfrozen);
462 }
463 }
464
465 #ifdef CONFIG_FSFREEZE
466 const char *ga_fsfreeze_hook(GAState *s)
467 {
468 return s->fsfreeze_hook;
469 }
470 #endif
471
472 static void become_daemon(const char *pidfile)
473 {
474 #ifndef _WIN32
475 pid_t pid, sid;
476
477 pid = fork();
478 if (pid < 0) {
479 exit(EXIT_FAILURE);
480 }
481 if (pid > 0) {
482 exit(EXIT_SUCCESS);
483 }
484
485 if (pidfile) {
486 if (!ga_open_pidfile(pidfile)) {
487 g_critical("failed to create pidfile");
488 exit(EXIT_FAILURE);
489 }
490 }
491
492 umask(S_IRWXG | S_IRWXO);
493 sid = setsid();
494 if (sid < 0) {
495 goto fail;
496 }
497 if ((chdir("/")) < 0) {
498 goto fail;
499 }
500
501 reopen_fd_to_null(STDIN_FILENO);
502 reopen_fd_to_null(STDOUT_FILENO);
503 reopen_fd_to_null(STDERR_FILENO);
504 return;
505
506 fail:
507 if (pidfile) {
508 unlink(pidfile);
509 }
510 g_critical("failed to daemonize");
511 exit(EXIT_FAILURE);
512 #endif
513 }
514
515 static int send_response(GAState *s, QObject *payload)
516 {
517 const char *buf;
518 QString *payload_qstr, *response_qstr;
519 GIOStatus status;
520
521 g_assert(payload && s->channel);
522
523 payload_qstr = qobject_to_json(payload);
524 if (!payload_qstr) {
525 return -EINVAL;
526 }
527
528 if (s->delimit_response) {
529 s->delimit_response = false;
530 response_qstr = qstring_new();
531 qstring_append_chr(response_qstr, QGA_SENTINEL_BYTE);
532 qstring_append(response_qstr, qstring_get_str(payload_qstr));
533 QDECREF(payload_qstr);
534 } else {
535 response_qstr = payload_qstr;
536 }
537
538 qstring_append_chr(response_qstr, '\n');
539 buf = qstring_get_str(response_qstr);
540 status = ga_channel_write_all(s->channel, buf, strlen(buf));
541 QDECREF(response_qstr);
542 if (status != G_IO_STATUS_NORMAL) {
543 return -EIO;
544 }
545
546 return 0;
547 }
548
549 static void process_command(GAState *s, QDict *req)
550 {
551 QObject *rsp = NULL;
552 int ret;
553
554 g_assert(req);
555 g_debug("processing command");
556 rsp = qmp_dispatch(QOBJECT(req));
557 if (rsp) {
558 ret = send_response(s, rsp);
559 if (ret) {
560 g_warning("error sending response: %s", strerror(ret));
561 }
562 qobject_decref(rsp);
563 }
564 }
565
566 /* handle requests/control events coming in over the channel */
567 static void process_event(JSONMessageParser *parser, QList *tokens)
568 {
569 GAState *s = container_of(parser, GAState, parser);
570 QObject *obj;
571 QDict *qdict;
572 Error *err = NULL;
573 int ret;
574
575 g_assert(s && parser);
576
577 g_debug("process_event: called");
578 obj = json_parser_parse_err(tokens, NULL, &err);
579 if (err || !obj || qobject_type(obj) != QTYPE_QDICT) {
580 qobject_decref(obj);
581 qdict = qdict_new();
582 if (!err) {
583 g_warning("failed to parse event: unknown error");
584 error_setg(&err, QERR_JSON_PARSING);
585 } else {
586 g_warning("failed to parse event: %s", error_get_pretty(err));
587 }
588 qdict_put_obj(qdict, "error", qmp_build_error_object(err));
589 error_free(err);
590 } else {
591 qdict = qobject_to_qdict(obj);
592 }
593
594 g_assert(qdict);
595
596 /* handle host->guest commands */
597 if (qdict_haskey(qdict, "execute")) {
598 process_command(s, qdict);
599 } else {
600 if (!qdict_haskey(qdict, "error")) {
601 QDECREF(qdict);
602 qdict = qdict_new();
603 g_warning("unrecognized payload format");
604 error_setg(&err, QERR_UNSUPPORTED);
605 qdict_put_obj(qdict, "error", qmp_build_error_object(err));
606 error_free(err);
607 }
608 ret = send_response(s, QOBJECT(qdict));
609 if (ret < 0) {
610 g_warning("error sending error response: %s", strerror(-ret));
611 }
612 }
613
614 QDECREF(qdict);
615 }
616
617 /* false return signals GAChannel to close the current client connection */
618 static gboolean channel_event_cb(GIOCondition condition, gpointer data)
619 {
620 GAState *s = data;
621 gchar buf[QGA_READ_COUNT_DEFAULT+1];
622 gsize count;
623 GError *err = NULL;
624 GIOStatus status = ga_channel_read(s->channel, buf, QGA_READ_COUNT_DEFAULT, &count);
625 if (err != NULL) {
626 g_warning("error reading channel: %s", err->message);
627 g_error_free(err);
628 return false;
629 }
630 switch (status) {
631 case G_IO_STATUS_ERROR:
632 g_warning("error reading channel");
633 return false;
634 case G_IO_STATUS_NORMAL:
635 buf[count] = 0;
636 g_debug("read data, count: %d, data: %s", (int)count, buf);
637 json_message_parser_feed(&s->parser, (char *)buf, (int)count);
638 break;
639 case G_IO_STATUS_EOF:
640 g_debug("received EOF");
641 if (!s->virtio) {
642 return false;
643 }
644 /* fall through */
645 case G_IO_STATUS_AGAIN:
646 /* virtio causes us to spin here when no process is attached to
647 * host-side chardev. sleep a bit to mitigate this
648 */
649 if (s->virtio) {
650 usleep(100*1000);
651 }
652 return true;
653 default:
654 g_warning("unknown channel read status, closing");
655 return false;
656 }
657 return true;
658 }
659
660 static gboolean channel_init(GAState *s, const gchar *method, const gchar *path)
661 {
662 GAChannelMethod channel_method;
663
664 if (strcmp(method, "virtio-serial") == 0) {
665 s->virtio = true; /* virtio requires special handling in some cases */
666 channel_method = GA_CHANNEL_VIRTIO_SERIAL;
667 } else if (strcmp(method, "isa-serial") == 0) {
668 channel_method = GA_CHANNEL_ISA_SERIAL;
669 } else if (strcmp(method, "unix-listen") == 0) {
670 channel_method = GA_CHANNEL_UNIX_LISTEN;
671 } else {
672 g_critical("unsupported channel method/type: %s", method);
673 return false;
674 }
675
676 s->channel = ga_channel_new(channel_method, path, channel_event_cb, s);
677 if (!s->channel) {
678 g_critical("failed to create guest agent channel");
679 return false;
680 }
681
682 return true;
683 }
684
685 #ifdef _WIN32
686 DWORD WINAPI service_ctrl_handler(DWORD ctrl, DWORD type, LPVOID data,
687 LPVOID ctx)
688 {
689 DWORD ret = NO_ERROR;
690 GAService *service = &ga_state->service;
691
692 switch (ctrl)
693 {
694 case SERVICE_CONTROL_STOP:
695 case SERVICE_CONTROL_SHUTDOWN:
696 quit_handler(SIGTERM);
697 service->status.dwCurrentState = SERVICE_STOP_PENDING;
698 SetServiceStatus(service->status_handle, &service->status);
699 break;
700
701 default:
702 ret = ERROR_CALL_NOT_IMPLEMENTED;
703 }
704 return ret;
705 }
706
707 VOID WINAPI service_main(DWORD argc, TCHAR *argv[])
708 {
709 GAService *service = &ga_state->service;
710
711 service->status_handle = RegisterServiceCtrlHandlerEx(QGA_SERVICE_NAME,
712 service_ctrl_handler, NULL);
713
714 if (service->status_handle == 0) {
715 g_critical("Failed to register extended requests function!\n");
716 return;
717 }
718
719 service->status.dwServiceType = SERVICE_WIN32;
720 service->status.dwCurrentState = SERVICE_RUNNING;
721 service->status.dwControlsAccepted = SERVICE_ACCEPT_STOP | SERVICE_ACCEPT_SHUTDOWN;
722 service->status.dwWin32ExitCode = NO_ERROR;
723 service->status.dwServiceSpecificExitCode = NO_ERROR;
724 service->status.dwCheckPoint = 0;
725 service->status.dwWaitHint = 0;
726 SetServiceStatus(service->status_handle, &service->status);
727
728 g_main_loop_run(ga_state->main_loop);
729
730 service->status.dwCurrentState = SERVICE_STOPPED;
731 SetServiceStatus(service->status_handle, &service->status);
732 }
733 #endif
734
735 static void set_persistent_state_defaults(GAPersistentState *pstate)
736 {
737 g_assert(pstate);
738 pstate->fd_counter = QGA_PSTATE_DEFAULT_FD_COUNTER;
739 }
740
741 static void persistent_state_from_keyfile(GAPersistentState *pstate,
742 GKeyFile *keyfile)
743 {
744 g_assert(pstate);
745 g_assert(keyfile);
746 /* if any fields are missing, either because the file was tampered with
747 * by agents of chaos, or because the field wasn't present at the time the
748 * file was created, the best we can ever do is start over with the default
749 * values. so load them now, and ignore any errors in accessing key-value
750 * pairs
751 */
752 set_persistent_state_defaults(pstate);
753
754 if (g_key_file_has_key(keyfile, "global", "fd_counter", NULL)) {
755 pstate->fd_counter =
756 g_key_file_get_integer(keyfile, "global", "fd_counter", NULL);
757 }
758 }
759
760 static void persistent_state_to_keyfile(const GAPersistentState *pstate,
761 GKeyFile *keyfile)
762 {
763 g_assert(pstate);
764 g_assert(keyfile);
765
766 g_key_file_set_integer(keyfile, "global", "fd_counter", pstate->fd_counter);
767 }
768
769 static gboolean write_persistent_state(const GAPersistentState *pstate,
770 const gchar *path)
771 {
772 GKeyFile *keyfile = g_key_file_new();
773 GError *gerr = NULL;
774 gboolean ret = true;
775 gchar *data = NULL;
776 gsize data_len;
777
778 g_assert(pstate);
779
780 persistent_state_to_keyfile(pstate, keyfile);
781 data = g_key_file_to_data(keyfile, &data_len, &gerr);
782 if (gerr) {
783 g_critical("failed to convert persistent state to string: %s",
784 gerr->message);
785 ret = false;
786 goto out;
787 }
788
789 g_file_set_contents(path, data, data_len, &gerr);
790 if (gerr) {
791 g_critical("failed to write persistent state to %s: %s",
792 path, gerr->message);
793 ret = false;
794 goto out;
795 }
796
797 out:
798 if (gerr) {
799 g_error_free(gerr);
800 }
801 if (keyfile) {
802 g_key_file_free(keyfile);
803 }
804 g_free(data);
805 return ret;
806 }
807
808 static gboolean read_persistent_state(GAPersistentState *pstate,
809 const gchar *path, gboolean frozen)
810 {
811 GKeyFile *keyfile = NULL;
812 GError *gerr = NULL;
813 struct stat st;
814 gboolean ret = true;
815
816 g_assert(pstate);
817
818 if (stat(path, &st) == -1) {
819 /* it's okay if state file doesn't exist, but any other error
820 * indicates a permissions issue or some other misconfiguration
821 * that we likely won't be able to recover from.
822 */
823 if (errno != ENOENT) {
824 g_critical("unable to access state file at path %s: %s",
825 path, strerror(errno));
826 ret = false;
827 goto out;
828 }
829
830 /* file doesn't exist. initialize state to default values and
831 * attempt to save now. (we could wait till later when we have
832 * modified state we need to commit, but if there's a problem,
833 * such as a missing parent directory, we want to catch it now)
834 *
835 * there is a potential scenario where someone either managed to
836 * update the agent from a version that didn't use a key store
837 * while qemu-ga thought the filesystem was frozen, or
838 * deleted the key store prior to issuing a fsfreeze, prior
839 * to restarting the agent. in this case we go ahead and defer
840 * initial creation till we actually have modified state to
841 * write, otherwise fail to recover from freeze.
842 */
843 set_persistent_state_defaults(pstate);
844 if (!frozen) {
845 ret = write_persistent_state(pstate, path);
846 if (!ret) {
847 g_critical("unable to create state file at path %s", path);
848 ret = false;
849 goto out;
850 }
851 }
852 ret = true;
853 goto out;
854 }
855
856 keyfile = g_key_file_new();
857 g_key_file_load_from_file(keyfile, path, 0, &gerr);
858 if (gerr) {
859 g_critical("error loading persistent state from path: %s, %s",
860 path, gerr->message);
861 ret = false;
862 goto out;
863 }
864
865 persistent_state_from_keyfile(pstate, keyfile);
866
867 out:
868 if (keyfile) {
869 g_key_file_free(keyfile);
870 }
871 if (gerr) {
872 g_error_free(gerr);
873 }
874
875 return ret;
876 }
877
878 int64_t ga_get_fd_handle(GAState *s, Error **errp)
879 {
880 int64_t handle;
881
882 g_assert(s->pstate_filepath);
883 /* we blacklist commands and avoid operations that potentially require
884 * writing to disk when we're in a frozen state. this includes opening
885 * new files, so we should never get here in that situation
886 */
887 g_assert(!ga_is_frozen(s));
888
889 handle = s->pstate.fd_counter++;
890
891 /* This should never happen on a reasonable timeframe, as guest-file-open
892 * would have to be issued 2^63 times */
893 if (s->pstate.fd_counter == INT64_MAX) {
894 abort();
895 }
896
897 if (!write_persistent_state(&s->pstate, s->pstate_filepath)) {
898 error_setg(errp, "failed to commit persistent state to disk");
899 return -1;
900 }
901
902 return handle;
903 }
904
905 static void ga_print_cmd(QmpCommand *cmd, void *opaque)
906 {
907 printf("%s\n", qmp_command_name(cmd));
908 }
909
910 static GList *split_list(const gchar *str, const gchar *delim)
911 {
912 GList *list = NULL;
913 int i;
914 gchar **strv;
915
916 strv = g_strsplit(str, delim, -1);
917 for (i = 0; strv[i]; i++) {
918 list = g_list_prepend(list, strv[i]);
919 }
920 g_free(strv);
921
922 return list;
923 }
924
925 typedef struct GAConfig {
926 char *channel_path;
927 char *method;
928 char *log_filepath;
929 char *pid_filepath;
930 #ifdef CONFIG_FSFREEZE
931 char *fsfreeze_hook;
932 #endif
933 char *state_dir;
934 #ifdef _WIN32
935 const char *service;
936 #endif
937 gchar *bliststr; /* blacklist may point to this string */
938 GList *blacklist;
939 int daemonize;
940 GLogLevelFlags log_level;
941 int dumpconf;
942 } GAConfig;
943
944 static void config_load(GAConfig *config)
945 {
946 GError *gerr = NULL;
947 GKeyFile *keyfile;
948
949 /* read system config */
950 keyfile = g_key_file_new();
951 if (!g_key_file_load_from_file(keyfile, QGA_CONF_DEFAULT, 0, &gerr)) {
952 goto end;
953 }
954 if (g_key_file_has_key(keyfile, "general", "daemon", NULL)) {
955 config->daemonize =
956 g_key_file_get_boolean(keyfile, "general", "daemon", &gerr);
957 }
958 if (g_key_file_has_key(keyfile, "general", "method", NULL)) {
959 config->method =
960 g_key_file_get_string(keyfile, "general", "method", &gerr);
961 }
962 if (g_key_file_has_key(keyfile, "general", "path", NULL)) {
963 config->channel_path =
964 g_key_file_get_string(keyfile, "general", "path", &gerr);
965 }
966 if (g_key_file_has_key(keyfile, "general", "logfile", NULL)) {
967 config->log_filepath =
968 g_key_file_get_string(keyfile, "general", "logfile", &gerr);
969 }
970 if (g_key_file_has_key(keyfile, "general", "pidfile", NULL)) {
971 config->pid_filepath =
972 g_key_file_get_string(keyfile, "general", "pidfile", &gerr);
973 }
974 #ifdef CONFIG_FSFREEZE
975 if (g_key_file_has_key(keyfile, "general", "fsfreeze-hook", NULL)) {
976 config->fsfreeze_hook =
977 g_key_file_get_string(keyfile,
978 "general", "fsfreeze-hook", &gerr);
979 }
980 #endif
981 if (g_key_file_has_key(keyfile, "general", "statedir", NULL)) {
982 config->state_dir =
983 g_key_file_get_string(keyfile, "general", "statedir", &gerr);
984 }
985 if (g_key_file_has_key(keyfile, "general", "verbose", NULL) &&
986 g_key_file_get_boolean(keyfile, "general", "verbose", &gerr)) {
987 /* enable all log levels */
988 config->log_level = G_LOG_LEVEL_MASK;
989 }
990 if (g_key_file_has_key(keyfile, "general", "blacklist", NULL)) {
991 config->bliststr =
992 g_key_file_get_string(keyfile, "general", "blacklist", &gerr);
993 config->blacklist = g_list_concat(config->blacklist,
994 split_list(config->bliststr, ","));
995 }
996
997 end:
998 g_key_file_free(keyfile);
999 if (gerr &&
1000 !(gerr->domain == G_FILE_ERROR && gerr->code == G_FILE_ERROR_NOENT)) {
1001 g_critical("error loading configuration from path: %s, %s",
1002 QGA_CONF_DEFAULT, gerr->message);
1003 exit(EXIT_FAILURE);
1004 }
1005 g_clear_error(&gerr);
1006 }
1007
1008 static gchar *list_join(GList *list, const gchar separator)
1009 {
1010 GString *str = g_string_new("");
1011
1012 while (list) {
1013 str = g_string_append(str, (gchar *)list->data);
1014 list = g_list_next(list);
1015 if (list) {
1016 str = g_string_append_c(str, separator);
1017 }
1018 }
1019
1020 return g_string_free(str, FALSE);
1021 }
1022
1023 static void config_dump(GAConfig *config)
1024 {
1025 GError *error = NULL;
1026 GKeyFile *keyfile;
1027 gchar *tmp;
1028
1029 keyfile = g_key_file_new();
1030 g_assert(keyfile);
1031
1032 g_key_file_set_boolean(keyfile, "general", "daemon", config->daemonize);
1033 g_key_file_set_string(keyfile, "general", "method", config->method);
1034 g_key_file_set_string(keyfile, "general", "path", config->channel_path);
1035 if (config->log_filepath) {
1036 g_key_file_set_string(keyfile, "general", "logfile",
1037 config->log_filepath);
1038 }
1039 g_key_file_set_string(keyfile, "general", "pidfile", config->pid_filepath);
1040 #ifdef CONFIG_FSFREEZE
1041 if (config->fsfreeze_hook) {
1042 g_key_file_set_string(keyfile, "general", "fsfreeze-hook",
1043 config->fsfreeze_hook);
1044 }
1045 #endif
1046 g_key_file_set_string(keyfile, "general", "statedir", config->state_dir);
1047 g_key_file_set_boolean(keyfile, "general", "verbose",
1048 config->log_level == G_LOG_LEVEL_MASK);
1049 tmp = list_join(config->blacklist, ',');
1050 g_key_file_set_string(keyfile, "general", "blacklist", tmp);
1051 g_free(tmp);
1052
1053 tmp = g_key_file_to_data(keyfile, NULL, &error);
1054 printf("%s", tmp);
1055
1056 g_free(tmp);
1057 g_key_file_free(keyfile);
1058 }
1059
1060 static void config_parse(GAConfig *config, int argc, char **argv)
1061 {
1062 const char *sopt = "hVvdm:p:l:f:F::b:s:t:D";
1063 int opt_ind = 0, ch;
1064 const struct option lopt[] = {
1065 { "help", 0, NULL, 'h' },
1066 { "version", 0, NULL, 'V' },
1067 { "dump-conf", 0, NULL, 'D' },
1068 { "logfile", 1, NULL, 'l' },
1069 { "pidfile", 1, NULL, 'f' },
1070 #ifdef CONFIG_FSFREEZE
1071 { "fsfreeze-hook", 2, NULL, 'F' },
1072 #endif
1073 { "verbose", 0, NULL, 'v' },
1074 { "method", 1, NULL, 'm' },
1075 { "path", 1, NULL, 'p' },
1076 { "daemonize", 0, NULL, 'd' },
1077 { "blacklist", 1, NULL, 'b' },
1078 #ifdef _WIN32
1079 { "service", 1, NULL, 's' },
1080 #endif
1081 { "statedir", 1, NULL, 't' },
1082 { NULL, 0, NULL, 0 }
1083 };
1084
1085 config->log_level = G_LOG_LEVEL_ERROR | G_LOG_LEVEL_CRITICAL;
1086
1087 while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
1088 switch (ch) {
1089 case 'm':
1090 g_free(config->method);
1091 config->method = g_strdup(optarg);
1092 break;
1093 case 'p':
1094 g_free(config->channel_path);
1095 config->channel_path = g_strdup(optarg);
1096 break;
1097 case 'l':
1098 g_free(config->log_filepath);
1099 config->log_filepath = g_strdup(optarg);
1100 break;
1101 case 'f':
1102 g_free(config->pid_filepath);
1103 config->pid_filepath = g_strdup(optarg);
1104 break;
1105 #ifdef CONFIG_FSFREEZE
1106 case 'F':
1107 g_free(config->fsfreeze_hook);
1108 config->fsfreeze_hook = g_strdup(optarg ?: QGA_FSFREEZE_HOOK_DEFAULT);
1109 break;
1110 #endif
1111 case 't':
1112 g_free(config->state_dir);
1113 config->state_dir = g_strdup(optarg);
1114 break;
1115 case 'v':
1116 /* enable all log levels */
1117 config->log_level = G_LOG_LEVEL_MASK;
1118 break;
1119 case 'V':
1120 printf("QEMU Guest Agent %s\n", QEMU_VERSION);
1121 exit(EXIT_SUCCESS);
1122 case 'd':
1123 config->daemonize = 1;
1124 break;
1125 case 'D':
1126 config->dumpconf = 1;
1127 break;
1128 case 'b': {
1129 if (is_help_option(optarg)) {
1130 qmp_for_each_command(ga_print_cmd, NULL);
1131 exit(EXIT_SUCCESS);
1132 }
1133 config->blacklist = g_list_concat(config->blacklist,
1134 split_list(optarg, ","));
1135 break;
1136 }
1137 #ifdef _WIN32
1138 case 's':
1139 config->service = optarg;
1140 if (strcmp(config->service, "install") == 0) {
1141 if (ga_install_vss_provider()) {
1142 exit(EXIT_FAILURE);
1143 }
1144 if (ga_install_service(config->channel_path,
1145 config->log_filepath, config->state_dir)) {
1146 exit(EXIT_FAILURE);
1147 }
1148 exit(EXIT_SUCCESS);
1149 } else if (strcmp(config->service, "uninstall") == 0) {
1150 ga_uninstall_vss_provider();
1151 exit(ga_uninstall_service());
1152 } else if (strcmp(config->service, "vss-install") == 0) {
1153 if (ga_install_vss_provider()) {
1154 exit(EXIT_FAILURE);
1155 }
1156 exit(EXIT_SUCCESS);
1157 } else if (strcmp(config->service, "vss-uninstall") == 0) {
1158 ga_uninstall_vss_provider();
1159 exit(EXIT_SUCCESS);
1160 } else {
1161 printf("Unknown service command.\n");
1162 exit(EXIT_FAILURE);
1163 }
1164 break;
1165 #endif
1166 case 'h':
1167 usage(argv[0]);
1168 exit(EXIT_SUCCESS);
1169 case '?':
1170 g_print("Unknown option, try '%s --help' for more information.\n",
1171 argv[0]);
1172 exit(EXIT_FAILURE);
1173 }
1174 }
1175 }
1176
1177 static void config_free(GAConfig *config)
1178 {
1179 g_free(config->method);
1180 g_free(config->log_filepath);
1181 g_free(config->pid_filepath);
1182 g_free(config->state_dir);
1183 g_free(config->channel_path);
1184 g_free(config->bliststr);
1185 #ifdef CONFIG_FSFREEZE
1186 g_free(config->fsfreeze_hook);
1187 #endif
1188 g_free(config);
1189 }
1190
1191 static bool check_is_frozen(GAState *s)
1192 {
1193 #ifndef _WIN32
1194 /* check if a previous instance of qemu-ga exited with filesystems' state
1195 * marked as frozen. this could be a stale value (a non-qemu-ga process
1196 * or reboot may have since unfrozen them), but better to require an
1197 * uneeded unfreeze than to risk hanging on start-up
1198 */
1199 struct stat st;
1200 if (stat(s->state_filepath_isfrozen, &st) == -1) {
1201 /* it's okay if the file doesn't exist, but if we can't access for
1202 * some other reason, such as permissions, there's a configuration
1203 * that needs to be addressed. so just bail now before we get into
1204 * more trouble later
1205 */
1206 if (errno != ENOENT) {
1207 g_critical("unable to access state file at path %s: %s",
1208 s->state_filepath_isfrozen, strerror(errno));
1209 return EXIT_FAILURE;
1210 }
1211 } else {
1212 g_warning("previous instance appears to have exited with frozen"
1213 " filesystems. deferring logging/pidfile creation and"
1214 " disabling non-fsfreeze-safe commands until"
1215 " guest-fsfreeze-thaw is issued, or filesystems are"
1216 " manually unfrozen and the file %s is removed",
1217 s->state_filepath_isfrozen);
1218 return true;
1219 }
1220 #endif
1221 return false;
1222 }
1223
1224 static int run_agent(GAState *s, GAConfig *config)
1225 {
1226 ga_state = s;
1227
1228 g_log_set_default_handler(ga_log, s);
1229 g_log_set_fatal_mask(NULL, G_LOG_LEVEL_ERROR);
1230 ga_enable_logging(s);
1231
1232 #ifdef _WIN32
1233 /* On win32 the state directory is application specific (be it the default
1234 * or a user override). We got past the command line parsing; let's create
1235 * the directory (with any intermediate directories). If we run into an
1236 * error later on, we won't try to clean up the directory, it is considered
1237 * persistent.
1238 */
1239 if (g_mkdir_with_parents(config->state_dir, S_IRWXU) == -1) {
1240 g_critical("unable to create (an ancestor of) the state directory"
1241 " '%s': %s", config->state_dir, strerror(errno));
1242 return EXIT_FAILURE;
1243 }
1244 #endif
1245
1246 if (ga_is_frozen(s)) {
1247 if (config->daemonize) {
1248 /* delay opening/locking of pidfile till filesystems are unfrozen */
1249 s->deferred_options.pid_filepath = config->pid_filepath;
1250 become_daemon(NULL);
1251 }
1252 if (config->log_filepath) {
1253 /* delay opening the log file till filesystems are unfrozen */
1254 s->deferred_options.log_filepath = config->log_filepath;
1255 }
1256 ga_disable_logging(s);
1257 qmp_for_each_command(ga_disable_non_whitelisted, NULL);
1258 } else {
1259 if (config->daemonize) {
1260 become_daemon(config->pid_filepath);
1261 }
1262 if (config->log_filepath) {
1263 FILE *log_file = ga_open_logfile(config->log_filepath);
1264 if (!log_file) {
1265 g_critical("unable to open specified log file: %s",
1266 strerror(errno));
1267 return EXIT_FAILURE;
1268 }
1269 s->log_file = log_file;
1270 }
1271 }
1272
1273 /* load persistent state from disk */
1274 if (!read_persistent_state(&s->pstate,
1275 s->pstate_filepath,
1276 ga_is_frozen(s))) {
1277 g_critical("failed to load persistent state");
1278 return EXIT_FAILURE;
1279 }
1280
1281 config->blacklist = ga_command_blacklist_init(config->blacklist);
1282 if (config->blacklist) {
1283 GList *l = config->blacklist;
1284 s->blacklist = config->blacklist;
1285 do {
1286 g_debug("disabling command: %s", (char *)l->data);
1287 qmp_disable_command(l->data);
1288 l = g_list_next(l);
1289 } while (l);
1290 }
1291 s->command_state = ga_command_state_new();
1292 ga_command_state_init(s, s->command_state);
1293 ga_command_state_init_all(s->command_state);
1294 json_message_parser_init(&s->parser, process_event);
1295 ga_state = s;
1296 #ifndef _WIN32
1297 if (!register_signal_handlers()) {
1298 g_critical("failed to register signal handlers");
1299 return EXIT_FAILURE;
1300 }
1301 #endif
1302
1303 s->main_loop = g_main_loop_new(NULL, false);
1304 if (!channel_init(ga_state, config->method, config->channel_path)) {
1305 g_critical("failed to initialize guest agent channel");
1306 return EXIT_FAILURE;
1307 }
1308 #ifndef _WIN32
1309 g_main_loop_run(ga_state->main_loop);
1310 #else
1311 if (config->daemonize) {
1312 SERVICE_TABLE_ENTRY service_table[] = {
1313 { (char *)QGA_SERVICE_NAME, service_main }, { NULL, NULL } };
1314 StartServiceCtrlDispatcher(service_table);
1315 } else {
1316 g_main_loop_run(ga_state->main_loop);
1317 }
1318 #endif
1319
1320 return EXIT_SUCCESS;
1321 }
1322
1323 static void free_blacklist_entry(gpointer entry, gpointer unused)
1324 {
1325 g_free(entry);
1326 }
1327
1328 int main(int argc, char **argv)
1329 {
1330 int ret = EXIT_SUCCESS;
1331 GAState *s = g_new0(GAState, 1);
1332 GAConfig *config = g_new0(GAConfig, 1);
1333
1334 module_call_init(MODULE_INIT_QAPI);
1335
1336 init_dfl_pathnames();
1337 config_load(config);
1338 config_parse(config, argc, argv);
1339
1340 if (config->pid_filepath == NULL) {
1341 config->pid_filepath = g_strdup(dfl_pathnames.pidfile);
1342 }
1343
1344 if (config->state_dir == NULL) {
1345 config->state_dir = g_strdup(dfl_pathnames.state_dir);
1346 }
1347
1348 if (config->method == NULL) {
1349 config->method = g_strdup("virtio-serial");
1350 }
1351
1352 if (config->channel_path == NULL) {
1353 if (strcmp(config->method, "virtio-serial") == 0) {
1354 /* try the default path for the virtio-serial port */
1355 config->channel_path = g_strdup(QGA_VIRTIO_PATH_DEFAULT);
1356 } else if (strcmp(config->method, "isa-serial") == 0) {
1357 /* try the default path for the serial port - COM1 */
1358 config->channel_path = g_strdup(QGA_SERIAL_PATH_DEFAULT);
1359 } else {
1360 g_critical("must specify a path for this channel");
1361 ret = EXIT_FAILURE;
1362 goto end;
1363 }
1364 }
1365
1366 s->log_level = config->log_level;
1367 s->log_file = stderr;
1368 #ifdef CONFIG_FSFREEZE
1369 s->fsfreeze_hook = config->fsfreeze_hook;
1370 #endif
1371 s->pstate_filepath = g_strdup_printf("%s/qga.state", config->state_dir);
1372 s->state_filepath_isfrozen = g_strdup_printf("%s/qga.state.isfrozen",
1373 config->state_dir);
1374 s->frozen = check_is_frozen(s);
1375
1376 if (config->dumpconf) {
1377 config_dump(config);
1378 goto end;
1379 }
1380
1381 ret = run_agent(s, config);
1382
1383 end:
1384 if (s->command_state) {
1385 ga_command_state_cleanup_all(s->command_state);
1386 }
1387 if (s->channel) {
1388 ga_channel_free(s->channel);
1389 }
1390 g_list_foreach(config->blacklist, free_blacklist_entry, NULL);
1391 g_free(s->pstate_filepath);
1392 g_free(s->state_filepath_isfrozen);
1393
1394 if (config->daemonize) {
1395 unlink(config->pid_filepath);
1396 }
1397
1398 config_free(config);
1399
1400 return ret;
1401 }