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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * in kernel monitor support: allows rv to control in-kernel monitors.
4 *
5 * Copyright (C) 2022 Red Hat Inc, Daniel Bristot de Oliveira <[email protected]>
6 */
7#include <getopt.h>
8#include <stdlib.h>
9#include <stdio.h>
10#include <string.h>
11#include <errno.h>
12#include <unistd.h>
13#include <dirent.h>
14
15#include <trace.h>
16#include <utils.h>
17#include <rv.h>
18
19static int config_has_id;
20static int config_is_container;
21static int config_my_pid;
22static int config_trace;
23
24static char *config_initial_reactor;
25static char *config_reactor;
26
27/*
28 * __ikm_read_enable - reads monitor's enable status
29 *
30 * __does not log errors.
31 *
32 * Returns the current status, or -1 if the monitor does not exist,
33 * __hence not logging errors.
34 */
35static int __ikm_read_enable(char *monitor_name)
36{
37 char path[MAX_PATH];
38 long long enabled;
39 int retval;
40
41 snprintf(path, MAX_PATH, "rv/monitors/%s/enable", monitor_name);
42
43 retval = tracefs_instance_file_read_number(NULL, path, &enabled);
44 if (retval < 0)
45 return -1;
46
47 return enabled;
48}
49
50/*
51 * __ikm_find_monitor - find the full name of a possibly nested module
52 *
53 * __does not log errors.
54 *
55 * Returns 1 if we found the monitor, -1 on error and 0 if it does not exist.
56 * The string out_name is populated with the full name, which can be
57 * equal to monitor_name or container/monitor_name if nested
58 */
59static int __ikm_find_monitor_name(char *monitor_name, char *out_name)
60{
61 char *available_monitors, *cursor, *line;
62 int len = strlen(monitor_name);
63 int found = 0;
64
65 available_monitors = tracefs_instance_file_read(NULL, "rv/available_monitors", NULL);
66 if (!available_monitors)
67 return -1;
68
69 config_is_container = 0;
70 cursor = available_monitors;
71 while ((line = strsep(&cursor, "\n"))) {
72 char *colon = strchr(line, ':');
73
74 if (strcmp(line, monitor_name) && (!colon || strcmp(colon + 1, monitor_name)))
75 continue;
76
77 strncpy(out_name, line, 2 * MAX_DA_NAME_LEN);
78 out_name[2 * MAX_DA_NAME_LEN - 1] = '\0';
79
80 if (colon) {
81 out_name[colon - line] = '/';
82 } else {
83 /* If there are children, they are on the next line. */
84 line = strsep(&cursor, "\n");
85 if (line && !strncmp(line, monitor_name, len) && line[len] == ':')
86 config_is_container = 1;
87 }
88
89 found = 1;
90 break;
91 }
92
93 free(available_monitors);
94 return found;
95}
96
97/*
98 * ikm_read_enable - reads monitor's enable status
99 *
100 * Returns the current status, or -1 on error.
101 */
102static int ikm_read_enable(char *monitor_name)
103{
104 int enabled;
105
106 enabled = __ikm_read_enable(monitor_name);
107 if (enabled < 0) {
108 err_msg("ikm: fail read enabled: %d\n", enabled);
109 return -1;
110 }
111
112 debug_msg("ikm: read enabled: %d\n", enabled);
113
114 return enabled;
115}
116
117/*
118 * ikm_write_enable - write to the monitor's enable file
119 *
120 * Return the number of bytes written, -1 on error.
121 */
122static int ikm_write_enable(char *monitor_name, char *enable_disable)
123{
124 char path[MAX_PATH];
125 int retval;
126
127 debug_msg("ikm: writing enabled: %s\n", enable_disable);
128
129 snprintf(path, MAX_PATH, "rv/monitors/%s/enable", monitor_name);
130 retval = tracefs_instance_file_write(NULL, path, enable_disable);
131 if (retval < strlen(enable_disable)) {
132 err_msg("ikm: writing enabled: %s\n", enable_disable);
133 return -1;
134 }
135
136 return retval;
137}
138
139/*
140 * ikm_enable - enable a monitor
141 *
142 * Returns -1 on failure. Success otherwise.
143 */
144static int ikm_enable(char *monitor_name)
145{
146 return ikm_write_enable(monitor_name, "1");
147}
148
149/*
150 * ikm_disable - disable a monitor
151 *
152 * Returns -1 on failure. Success otherwise.
153 */
154static int ikm_disable(char *monitor_name)
155{
156 return ikm_write_enable(monitor_name, "0");
157}
158
159/*
160 * ikm_read_desc - read monitors' description
161 *
162 * Return a dynamically allocated string with the monitor's
163 * description, NULL otherwise.
164 */
165static char *ikm_read_desc(char *monitor_name)
166{
167 char path[MAX_PATH];
168 char *desc;
169
170 snprintf(path, MAX_PATH, "rv/monitors/%s/desc", monitor_name);
171 desc = tracefs_instance_file_read(NULL, path, NULL);
172 if (!desc) {
173 err_msg("ikm: error reading monitor %s desc\n", monitor_name);
174 return NULL;
175 }
176
177 *strstr(desc, "\n") = '\0';
178
179 return desc;
180}
181
182/*
183 * ikm_fill_monitor_definition - fill monitor's definition
184 *
185 * Returns -1 on error, 1 if the monitor does not belong in the container, 0 otherwise.
186 * container can be NULL
187 */
188static int ikm_fill_monitor_definition(char *name, struct monitor *ikm, char *container)
189{
190 int enabled;
191 char *desc, *nested_name;
192
193 nested_name = strstr(name, ":");
194 if (nested_name) {
195 /* it belongs in container if it starts with "container:" */
196 if (container) {
197 int len = strlen(container);
198
199 if (strncmp(name, container, len) || name[len] != ':')
200 return 1;
201 }
202 *nested_name = '/';
203 ++nested_name;
204 ikm->nested = 1;
205 } else {
206 if (container)
207 return 1;
208 nested_name = name;
209 ikm->nested = 0;
210 }
211
212 enabled = ikm_read_enable(name);
213 if (enabled < 0) {
214 err_msg("ikm: monitor %s fail to read enable file, bug?\n", name);
215 return -1;
216 }
217
218 desc = ikm_read_desc(name);
219 if (!desc) {
220 err_msg("ikm: monitor %s does not have desc file, bug?\n", name);
221 return -1;
222 }
223
224 strncpy(ikm->name, nested_name, sizeof(ikm->name) - 1);
225 ikm->name[sizeof(ikm->name) - 1] = '\0';
226 ikm->enabled = enabled;
227 strncpy(ikm->desc, desc, sizeof(ikm->desc) - 1);
228 ikm->desc[sizeof(ikm->desc) - 1] = '\0';
229 free(desc);
230
231 return 0;
232}
233
234/*
235 * ikm_write_reactor - switch the reactor to *reactor
236 *
237 * Return the number or characters written, -1 on error.
238 */
239static int ikm_write_reactor(char *monitor_name, char *reactor)
240{
241 char path[MAX_PATH];
242 int retval;
243
244 snprintf(path, MAX_PATH, "rv/monitors/%s/reactors", monitor_name);
245 retval = tracefs_instance_file_write(NULL, path, reactor);
246 debug_msg("ikm: write \"%s\" reactors: %d\n", reactor, retval);
247
248 return retval;
249}
250
251/*
252 * ikm_read_reactor - read the reactors file
253 *
254 * Returns a dynamically allocated string with monitor's
255 * available reactors, or NULL on error.
256 */
257static char *ikm_read_reactor(char *monitor_name)
258{
259 char path[MAX_PATH];
260 char *reactors;
261
262 snprintf(path, MAX_PATH, "rv/monitors/%s/reactors", monitor_name);
263 reactors = tracefs_instance_file_read(NULL, path, NULL);
264 if (!reactors) {
265 err_msg("ikm: fail reading monitor's %s reactors file\n", monitor_name);
266 return NULL;
267 }
268
269 return reactors;
270}
271
272/*
273 * ikm_get_current_reactor - get the current enabled reactor
274 *
275 * Reads the reactors file and find the currently enabled
276 * [reactor].
277 *
278 * Returns a dynamically allocated memory with the current
279 * reactor. NULL otherwise.
280 */
281static char *ikm_get_current_reactor(char *monitor_name)
282{
283 char *reactors = ikm_read_reactor(monitor_name);
284 char *curr_reactor = NULL;
285 char *start;
286 char *end;
287
288 if (!reactors)
289 return NULL;
290
291 start = strstr(reactors, "[");
292 if (!start)
293 goto out_free;
294
295 start++;
296
297 end = strstr(start, "]");
298 if (!end)
299 goto out_free;
300
301 *end = '\0';
302
303 curr_reactor = calloc(strlen(start) + 1, sizeof(char));
304 if (!curr_reactor)
305 goto out_free;
306
307 strncpy(curr_reactor, start, strlen(start));
308 debug_msg("ikm: read current reactor %s\n", curr_reactor);
309
310out_free:
311 free(reactors);
312
313 return curr_reactor;
314}
315
316static int ikm_has_id(char *monitor_name)
317{
318 char path[MAX_PATH];
319 char *format;
320 int has_id;
321
322 snprintf(path, MAX_PATH, "events/rv/event_%s/format", monitor_name);
323 format = tracefs_instance_file_read(NULL, path, NULL);
324 if (!format) {
325 err_msg("ikm: fail reading monitor's %s format event file\n", monitor_name);
326 return -1;
327 }
328
329 /* print fmt: "%d: %s x %s -> %s %s", REC->id, ... */
330 has_id = !!strstr(format, "REC->id");
331
332 debug_msg("ikm: monitor %s has id: %s\n", monitor_name, has_id ? "yes" : "no");
333
334 free(format);
335
336 return has_id;
337}
338
339/**
340 * ikm_list_monitors - list all available monitors
341 *
342 * Returns 0 on success, -1 otherwise.
343 */
344int ikm_list_monitors(char *container)
345{
346 char *available_monitors;
347 struct monitor ikm = {0};
348 char *curr, *next;
349 int retval, list_monitor = 0;
350
351 available_monitors = tracefs_instance_file_read(NULL, "rv/available_monitors", NULL);
352
353 if (!available_monitors) {
354 err_msg("ikm: available monitors is not available, is CONFIG_RV enabled?\n");
355 return -1;
356 }
357
358 curr = available_monitors;
359 do {
360 next = strstr(curr, "\n");
361 *next = '\0';
362
363 retval = ikm_fill_monitor_definition(curr, &ikm, container);
364 if (retval < 0)
365 err_msg("ikm: error reading %d in kernel monitor, skipping\n", curr);
366
367 if (!retval) {
368 int indent = ikm.nested && !container;
369
370 list_monitor = 1;
371 printf("%s%-*s %s %s\n", indent ? " - " : "",
372 indent ? MAX_DA_NAME_LEN - 3 : MAX_DA_NAME_LEN,
373 ikm.name, ikm.desc, ikm.enabled ? "[ON]" : "[OFF]");
374 }
375 curr = ++next;
376
377 } while (strlen(curr));
378
379 if (!list_monitor) {
380 if (container)
381 printf("-- No monitor found in container %s --\n", container);
382 else
383 printf("-- No monitor found --\n");
384 }
385
386 free(available_monitors);
387
388 return 0;
389}
390
391static void ikm_print_header(struct trace_seq *s)
392{
393 trace_seq_printf(s, "%16s-%-8s %5s %5s ", "<TASK>", "PID", "[CPU]", "TYPE");
394 if (config_has_id)
395 trace_seq_printf(s, "%8s ", "ID");
396
397 trace_seq_printf(s, "%24s x %-24s -> %-24s %s\n",
398 "STATE",
399 "EVENT",
400 "NEXT_STATE",
401 "FINAL");
402
403 trace_seq_printf(s, "%16s %-8s %5s %5s ", " | ", " | ", " | ", " | ");
404
405 if (config_has_id)
406 trace_seq_printf(s, "%8s ", " | ");
407
408 trace_seq_printf(s, "%24s %-24s %-24s %s\n",
409 " | ",
410 " | ",
411 " | ",
412 "|");
413
414}
415
416/*
417 * ikm_event_handler - callback to handle event events
418 *
419 * Called any time a rv:"monitor"_event events is generated.
420 * It parses and prints event.
421 */
422static int
423ikm_event_handler(struct trace_seq *s, struct tep_record *record,
424 struct tep_event *trace_event, void *context)
425{
426 /* if needed: struct trace_instance *inst = context; */
427 char *state, *event, *next_state;
428 unsigned long long final_state;
429 unsigned long long pid;
430 unsigned long long id;
431 int val;
432 bool missing_id;
433
434 if (config_has_id)
435 missing_id = tep_get_field_val(s, trace_event, "id", record, &id, 1);
436
437 tep_get_common_field_val(s, trace_event, "common_pid", record, &pid, 1);
438
439 if (config_has_id && (config_my_pid == id))
440 return 0;
441 else if (config_my_pid == pid)
442 return 0;
443
444 tep_print_event(trace_event->tep, s, record, "%16s-%-8d [%.3d] ",
445 TEP_PRINT_COMM, TEP_PRINT_PID, TEP_PRINT_CPU);
446
447 if (config_is_container)
448 tep_print_event(trace_event->tep, s, record, "%s ", TEP_PRINT_NAME);
449 else
450 trace_seq_printf(s, "event ");
451
452 if (config_has_id) {
453 if (missing_id)
454 /* placeholder if we are dealing with a mixed-type container*/
455 trace_seq_printf(s, " ");
456 else
457 trace_seq_printf(s, "%8llu ", id);
458 }
459
460 state = tep_get_field_raw(s, trace_event, "state", record, &val, 0);
461 event = tep_get_field_raw(s, trace_event, "event", record, &val, 0);
462 next_state = tep_get_field_raw(s, trace_event, "next_state", record, &val, 0);
463 tep_get_field_val(s, trace_event, "final_state", record, &final_state, 1);
464
465 trace_seq_printf(s, "%24s x %-24s -> %-24s %s\n",
466 state,
467 event,
468 next_state,
469 final_state ? "Y" : "N");
470
471 trace_seq_do_printf(s);
472 trace_seq_reset(s);
473
474 return 0;
475}
476
477/*
478 * ikm_error_handler - callback to handle error events
479 *
480 * Called any time a rv:"monitor"_errors events is generated.
481 * It parses and prints event.
482 */
483static int
484ikm_error_handler(struct trace_seq *s, struct tep_record *record,
485 struct tep_event *trace_event, void *context)
486{
487 unsigned long long pid, id;
488 int cpu = record->cpu;
489 char *state, *event;
490 int val;
491 bool missing_id;
492
493 if (config_has_id)
494 missing_id = tep_get_field_val(s, trace_event, "id", record, &id, 1);
495
496 tep_get_common_field_val(s, trace_event, "common_pid", record, &pid, 1);
497
498 if (config_has_id && config_my_pid == id)
499 return 0;
500 else if (config_my_pid == pid)
501 return 0;
502
503 trace_seq_printf(s, "%8lld [%03d] ", pid, cpu);
504
505 if (config_is_container)
506 tep_print_event(trace_event->tep, s, record, "%s ", TEP_PRINT_NAME);
507 else
508 trace_seq_printf(s, "error ");
509
510 if (config_has_id) {
511 if (missing_id)
512 /* placeholder if we are dealing with a mixed-type container*/
513 trace_seq_printf(s, " ");
514 else
515 trace_seq_printf(s, "%8llu ", id);
516 }
517
518 state = tep_get_field_raw(s, trace_event, "state", record, &val, 0);
519 event = tep_get_field_raw(s, trace_event, "event", record, &val, 0);
520
521 trace_seq_printf(s, "%24s x %s\n", state, event);
522
523 trace_seq_do_printf(s);
524 trace_seq_reset(s);
525
526 return 0;
527}
528
529static int ikm_enable_trace_events(char *monitor_name, struct trace_instance *inst)
530{
531 char event[MAX_DA_NAME_LEN + 7]; /* max(error_,event_) + '0' = 7 */
532 int retval;
533
534 snprintf(event, sizeof(event), "event_%s", monitor_name);
535 retval = tracefs_event_enable(inst->inst, "rv", event);
536 if (retval)
537 return -1;
538
539 tep_register_event_handler(inst->tep, -1, "rv", event,
540 ikm_event_handler, NULL);
541
542 snprintf(event, sizeof(event), "error_%s", monitor_name);
543 retval = tracefs_event_enable(inst->inst, "rv", event);
544 if (retval)
545 return -1;
546
547 tep_register_event_handler(inst->tep, -1, "rv", event,
548 ikm_error_handler, NULL);
549
550 /* set if at least 1 monitor has id in case of a container */
551 config_has_id = ikm_has_id(monitor_name);
552 if (config_has_id < 0)
553 return -1;
554
555
556 return 0;
557}
558
559static int ikm_enable_trace_container(char *monitor_name,
560 struct trace_instance *inst)
561{
562 DIR *dp;
563 char *abs_path, rv_path[MAX_PATH];
564 struct dirent *ep;
565 int retval = 0;
566
567 snprintf(rv_path, MAX_PATH, "rv/monitors/%s", monitor_name);
568 abs_path = tracefs_instance_get_file(NULL, rv_path);
569 if (!abs_path)
570 return -1;
571 dp = opendir(abs_path);
572 if (!dp)
573 goto out_free;
574
575 while (!retval && (ep = readdir(dp))) {
576 if (ep->d_type != DT_DIR || ep->d_name[0] == '.')
577 continue;
578 retval = ikm_enable_trace_events(ep->d_name, inst);
579 }
580
581 closedir(dp);
582out_free:
583 free(abs_path);
584 return retval;
585}
586
587/*
588 * ikm_setup_trace_instance - set up a tracing instance to collect data
589 *
590 * Create a trace instance, enable rv: events and enable the trace.
591 *
592 * Returns the trace_instance * with all set, NULL otherwise.
593 */
594static struct trace_instance *ikm_setup_trace_instance(char *monitor_name)
595{
596 struct trace_instance *inst;
597 int retval;
598
599 if (!config_trace)
600 return NULL;
601
602 /* alloc data */
603 inst = calloc(1, sizeof(*inst));
604 if (!inst) {
605 err_msg("ikm: failed to allocate trace instance");
606 goto out_err;
607 }
608
609 retval = trace_instance_init(inst, monitor_name);
610 if (retval)
611 goto out_free;
612
613 if (config_is_container)
614 retval = ikm_enable_trace_container(monitor_name, inst);
615 else
616 retval = ikm_enable_trace_events(monitor_name, inst);
617 if (retval)
618 goto out_inst;
619
620 /* ready to enable */
621 tracefs_trace_on(inst->inst);
622
623 return inst;
624
625out_inst:
626 trace_instance_destroy(inst);
627out_free:
628 free(inst);
629out_err:
630 return NULL;
631}
632
633/**
634 * ikm_destroy_trace_instance - destroy a previously created instance
635 */
636static void ikm_destroy_trace_instance(struct trace_instance *inst)
637{
638 if (!inst)
639 return;
640
641 trace_instance_destroy(inst);
642 free(inst);
643}
644
645/*
646 * ikm_usage_print_reactors - print all available reactors, one per line.
647 */
648static void ikm_usage_print_reactors(void)
649{
650 char *reactors = tracefs_instance_file_read(NULL, "rv/available_reactors", NULL);
651 char *start, *end;
652
653 if (!reactors)
654 return;
655
656 fprintf(stderr, " available reactors:");
657
658 start = reactors;
659 end = strstr(start, "\n");
660
661 while (end) {
662 *end = '\0';
663
664 fprintf(stderr, " %s", start);
665
666 start = ++end;
667 end = strstr(start, "\n");
668 }
669
670 fprintf(stderr, "\n");
671}
672/*
673 * ikm_usage - print usage
674 */
675static void ikm_usage(int exit_val, char *monitor_name, const char *fmt, ...)
676{
677
678 char message[1024];
679 va_list ap;
680 int i;
681
682 static const char *const usage[] = {
683 "",
684 " -h/--help: print this menu and the reactor list",
685 " -r/--reactor 'reactor': enables the 'reactor'",
686 " -s/--self: when tracing (-t), also trace rv command",
687 " -t/--trace: trace monitor's event",
688 " -v/--verbose: print debug messages",
689 "",
690 NULL,
691 };
692
693 va_start(ap, fmt);
694 vsnprintf(message, sizeof(message), fmt, ap);
695 va_end(ap);
696
697 fprintf(stderr, " %s\n", message);
698
699 fprintf(stderr, "\n usage: rv mon %s [-h] [-q] [-r reactor] [-s] [-v]", monitor_name);
700
701 for (i = 0; usage[i]; i++)
702 fprintf(stderr, "%s\n", usage[i]);
703
704 ikm_usage_print_reactors();
705 exit(exit_val);
706}
707
708/*
709 * parse_arguments - parse arguments and set config
710 */
711static int parse_arguments(char *monitor_name, int argc, char **argv)
712{
713 int c, retval;
714
715 config_my_pid = getpid();
716
717 while (1) {
718 static struct option long_options[] = {
719 {"help", no_argument, 0, 'h'},
720 {"reactor", required_argument, 0, 'r'},
721 {"self", no_argument, 0, 's'},
722 {"trace", no_argument, 0, 't'},
723 {"verbose", no_argument, 0, 'v'},
724 {0, 0, 0, 0}
725 };
726
727 /* getopt_long stores the option index here. */
728 int option_index = 0;
729
730 c = getopt_long(argc, argv, "hr:stv", long_options, &option_index);
731
732 /* detect the end of the options. */
733 if (c == -1)
734 break;
735
736 switch (c) {
737 case 'h':
738 ikm_usage(0, monitor_name, "help:");
739 break;
740 case 'r':
741 config_reactor = optarg;
742 break;
743 case 's':
744 config_my_pid = -1;
745 break;
746 case 't':
747 config_trace = 1;
748 break;
749 case 'v':
750 config_debug = 1;
751 break;
752 }
753 }
754
755 if (config_reactor) {
756 config_initial_reactor = ikm_get_current_reactor(monitor_name);
757 if (!config_initial_reactor)
758 ikm_usage(1, monitor_name,
759 "ikm: failed to read current reactor, are reactors enabled?");
760
761 retval = ikm_write_reactor(monitor_name, config_reactor);
762 if (retval <= 0)
763 ikm_usage(1, monitor_name,
764 "ikm: failed to set %s reactor, is it available?",
765 config_reactor);
766 }
767
768 debug_msg("ikm: my pid is %d\n", config_my_pid);
769
770 return 0;
771}
772
773/**
774 * ikm_run_monitor - apply configs and run the monitor
775 *
776 * Returns 1 if a monitor was found an executed, 0 if no
777 * monitors were found, or -1 on error.
778 */
779int ikm_run_monitor(char *monitor_name, int argc, char **argv)
780{
781 struct trace_instance *inst = NULL;
782 char *nested_name, full_name[2*MAX_DA_NAME_LEN];
783 int retval;
784
785 nested_name = strstr(monitor_name, ":");
786 if (nested_name)
787 ++nested_name;
788 else
789 nested_name = monitor_name;
790
791 retval = __ikm_find_monitor_name(monitor_name, full_name);
792 if (!retval)
793 return 0;
794 if (retval < 0) {
795 err_msg("ikm: error finding monitor %s\n", nested_name);
796 return -1;
797 }
798
799 retval = __ikm_read_enable(full_name);
800 if (retval) {
801 err_msg("ikm: monitor %s (in-kernel) is already enabled\n", nested_name);
802 return -1;
803 }
804
805 /* we should be good to go */
806 retval = parse_arguments(full_name, argc, argv);
807 if (retval)
808 ikm_usage(1, nested_name, "ikm: failed parsing arguments");
809
810 if (config_trace) {
811 inst = ikm_setup_trace_instance(nested_name);
812 if (!inst)
813 goto out_free_instance;
814 }
815
816 retval = ikm_enable(full_name);
817 if (retval < 0)
818 goto out_free_instance;
819
820 if (config_trace)
821 ikm_print_header(inst->seq);
822
823 while (!should_stop()) {
824 if (config_trace) {
825 retval = tracefs_iterate_raw_events(inst->tep,
826 inst->inst,
827 NULL,
828 0,
829 collect_registered_events,
830 inst);
831 if (retval) {
832 err_msg("ikm: error reading trace buffer\n");
833 break;
834 }
835 }
836
837 sleep(1);
838 }
839
840 ikm_disable(full_name);
841 ikm_destroy_trace_instance(inst);
842
843 if (config_reactor && config_initial_reactor)
844 ikm_write_reactor(full_name, config_initial_reactor);
845
846 return 1;
847
848out_free_instance:
849 ikm_destroy_trace_instance(inst);
850 if (config_reactor && config_initial_reactor)
851 ikm_write_reactor(full_name, config_initial_reactor);
852 return -1;
853}