1 // SPDX-License-Identifier: GPL-2.0
3 * in kernel monitor support: allows rv to control in-kernel monitors.
5 * Copyright (C) 2022 Red Hat Inc, Daniel Bristot de Oliveira <bristot@kernel.org>
17 static int config_has_id;
18 static int config_my_pid;
19 static int config_trace;
21 static char *config_initial_reactor;
22 static char *config_reactor;
25 * __ikm_read_enable - reads monitor's enable status
27 * __does not log errors.
29 * Returns the current status, or -1 if the monitor does not exist,
30 * __hence not logging errors.
32 static int __ikm_read_enable(char *monitor_name)
38 snprintf(path, MAX_PATH, "rv/monitors/%s/enable", monitor_name);
40 retval = tracefs_instance_file_read_number(NULL, path, &enabled);
48 * ikm_read_enable - reads monitor's enable status
50 * Returns the current status, or -1 on error.
52 static int ikm_read_enable(char *monitor_name)
56 enabled = __ikm_read_enable(monitor_name);
58 err_msg("ikm: fail read enabled: %d\n", enabled);
62 debug_msg("ikm: read enabled: %d\n", enabled);
68 * ikm_write_enable - write to the monitor's enable file
70 * Return the number of bytes written, -1 on error.
72 static int ikm_write_enable(char *monitor_name, char *enable_disable)
77 debug_msg("ikm: writing enabled: %s\n", enable_disable);
79 snprintf(path, MAX_PATH, "rv/monitors/%s/enable", monitor_name);
80 retval = tracefs_instance_file_write(NULL, path, enable_disable);
81 if (retval < strlen(enable_disable)) {
82 err_msg("ikm: writing enabled: %s\n", enable_disable);
90 * ikm_enable - enable a monitor
92 * Returns -1 on failure. Success otherwise.
94 static int ikm_enable(char *monitor_name)
96 return ikm_write_enable(monitor_name, "1");
100 * ikm_disable - disable a monitor
102 * Returns -1 on failure. Success otherwise.
104 static int ikm_disable(char *monitor_name)
106 return ikm_write_enable(monitor_name, "0");
110 * ikm_read_desc - read monitors' description
112 * Return a dynamically allocated string with the monitor's
113 * description, NULL otherwise.
115 static char *ikm_read_desc(char *monitor_name)
120 snprintf(path, MAX_PATH, "rv/monitors/%s/desc", monitor_name);
121 desc = tracefs_instance_file_read(NULL, path, NULL);
123 err_msg("ikm: error reading monitor %s desc\n", monitor_name);
127 *strstr(desc, "\n") = '\0';
133 * ikm_fill_monitor_definition - fill monitor's definition
135 * Returns -1 on error, 0 otherwise.
137 static int ikm_fill_monitor_definition(char *name, struct monitor *ikm)
142 enabled = ikm_read_enable(name);
144 err_msg("ikm: monitor %s fail to read enable file, bug?\n", name);
148 desc = ikm_read_desc(name);
150 err_msg("ikm: monitor %s does not have desc file, bug?\n", name);
154 strncpy(ikm->name, name, MAX_DA_NAME_LEN);
155 ikm->enabled = enabled;
156 strncpy(ikm->desc, desc, MAX_DESCRIPTION);
164 * ikm_write_reactor - switch the reactor to *reactor
166 * Return the number or characters written, -1 on error.
168 static int ikm_write_reactor(char *monitor_name, char *reactor)
173 snprintf(path, MAX_PATH, "rv/monitors/%s/reactors", monitor_name);
174 retval = tracefs_instance_file_write(NULL, path, reactor);
175 debug_msg("ikm: write \"%s\" reactors: %d\n", reactor, retval);
181 * ikm_read_reactor - read the reactors file
183 * Returns a dynamically allocated string with monitor's
184 * available reactors, or NULL on error.
186 static char *ikm_read_reactor(char *monitor_name)
191 snprintf(path, MAX_PATH, "rv/monitors/%s/reactors", monitor_name);
192 reactors = tracefs_instance_file_read(NULL, path, NULL);
194 err_msg("ikm: fail reading monitor's %s reactors file\n", monitor_name);
202 * ikm_get_current_reactor - get the current enabled reactor
204 * Reads the reactors file and find the currently enabled
207 * Returns a dynamically allocated memory with the current
208 * reactor. NULL otherwise.
210 static char *ikm_get_current_reactor(char *monitor_name)
212 char *reactors = ikm_read_reactor(monitor_name);
213 char *curr_reactor = NULL;
220 start = strstr(reactors, "[");
226 end = strstr(start, "]");
232 curr_reactor = calloc(strlen(start) + 1, sizeof(char));
236 strncpy(curr_reactor, start, strlen(start));
237 debug_msg("ikm: read current reactor %s\n", curr_reactor);
245 static int ikm_has_id(char *monitor_name)
251 snprintf(path, MAX_PATH, "events/rv/event_%s/format", monitor_name);
252 format = tracefs_instance_file_read(NULL, path, NULL);
254 err_msg("ikm: fail reading monitor's %s format event file\n", monitor_name);
258 /* print fmt: "%d: %s x %s -> %s %s", REC->id, ... */
259 has_id = !!strstr(format, "REC->id");
261 debug_msg("ikm: monitor %s has id: %s\n", monitor_name, has_id ? "yes" : "no");
269 * ikm_list_monitors - list all available monitors
271 * Returns 0 on success, -1 otherwise.
273 int ikm_list_monitors(void)
275 char *available_monitors;
280 available_monitors = tracefs_instance_file_read(NULL, "rv/available_monitors", NULL);
282 if (!available_monitors) {
283 err_msg("ikm: available monitors is not available, is CONFIG_RV enabled?\n");
287 curr = available_monitors;
289 next = strstr(curr, "\n");
292 retval = ikm_fill_monitor_definition(curr, &ikm);
294 err_msg("ikm: error reading %d in kernel monitor, skipping\n", curr);
296 printf("%-24s %s %s\n", ikm.name, ikm.desc, ikm.enabled ? "[ON]" : "[OFF]");
299 } while (strlen(curr));
301 free(available_monitors);
306 static void ikm_print_header(struct trace_seq *s)
308 trace_seq_printf(s, "%16s-%-8s %5s %5s ", "<TASK>", "PID", "[CPU]", "TYPE");
310 trace_seq_printf(s, "%8s ", "ID");
312 trace_seq_printf(s, "%24s x %-24s -> %-24s %s\n",
318 trace_seq_printf(s, "%16s %-8s %5s %5s ", " | ", " | ", " | ", " | ");
321 trace_seq_printf(s, "%8s ", " | ");
323 trace_seq_printf(s, "%24s %-24s %-24s %s\n",
332 * ikm_event_handler - callback to handle event events
334 * Called any time a rv:"monitor"_event events is generated.
335 * It parses and print event.
338 ikm_event_handler(struct trace_seq *s, struct tep_record *record,
339 struct tep_event *trace_event, void *context)
341 /* if needed: struct trace_instance *inst = context; */
342 char *state, *event, *next_state;
343 unsigned long long final_state;
344 unsigned long long pid;
345 unsigned long long id;
346 int cpu = record->cpu;
350 tep_get_field_val(s, trace_event, "id", record, &id, 1);
352 tep_get_common_field_val(s, trace_event, "common_pid", record, &pid, 1);
354 if (config_has_id && (config_my_pid == id))
356 else if (config_my_pid && (config_my_pid == pid))
359 tep_print_event(trace_event->tep, s, record, "%16s-%-8d ", TEP_PRINT_COMM, TEP_PRINT_PID);
361 trace_seq_printf(s, "[%.3d] event ", cpu);
364 trace_seq_printf(s, "%8llu ", id);
366 state = tep_get_field_raw(s, trace_event, "state", record, &val, 0);
367 event = tep_get_field_raw(s, trace_event, "event", record, &val, 0);
368 next_state = tep_get_field_raw(s, trace_event, "next_state", record, &val, 0);
369 tep_get_field_val(s, trace_event, "final_state", record, &final_state, 1);
371 trace_seq_printf(s, "%24s x %-24s -> %-24s %s\n",
375 final_state ? "Y" : "N");
377 trace_seq_do_printf(s);
384 * ikm_error_handler - callback to handle error events
386 * Called any time a rv:"monitor"_errors events is generated.
387 * It parses and print event.
390 ikm_error_handler(struct trace_seq *s, struct tep_record *record,
391 struct tep_event *trace_event, void *context)
393 unsigned long long pid, id;
394 int cpu = record->cpu;
399 tep_get_field_val(s, trace_event, "id", record, &id, 1);
401 tep_get_common_field_val(s, trace_event, "common_pid", record, &pid, 1);
403 if (config_has_id && config_my_pid == id)
405 else if (config_my_pid == pid)
408 trace_seq_printf(s, "%8lld [%03d] error ", pid, cpu);
411 trace_seq_printf(s, "%8llu ", id);
413 state = tep_get_field_raw(s, trace_event, "state", record, &val, 0);
414 event = tep_get_field_raw(s, trace_event, "event", record, &val, 0);
416 trace_seq_printf(s, "%24s x %s\n", state, event);
418 trace_seq_do_printf(s);
425 * ikm_setup_trace_instance - set up a tracing instance to collect data
427 * Create a trace instance, enable rv: events and enable the trace.
429 * Returns the trace_instance * with all set, NULL otherwise.
431 static struct trace_instance *ikm_setup_trace_instance(char *monitor_name)
433 char event[MAX_DA_NAME_LEN + 7]; /* max(error_,event_) + '0' = 7 */
434 struct trace_instance *inst;
440 config_has_id = ikm_has_id(monitor_name);
441 if (config_has_id < 0) {
442 err_msg("ikm: failed to read monitor %s event format\n", monitor_name);
447 inst = calloc(1, sizeof(*inst));
449 err_msg("ikm: failed to allocate trace instance");
453 retval = trace_instance_init(inst, monitor_name);
458 snprintf(event, sizeof(event), "event_%s", monitor_name);
459 retval = tracefs_event_enable(inst->inst, "rv", event);
463 tep_register_event_handler(inst->tep, -1, "rv", event,
464 ikm_event_handler, NULL);
466 snprintf(event, sizeof(event), "error_%s", monitor_name);
467 retval = tracefs_event_enable(inst->inst, "rv", event);
471 tep_register_event_handler(inst->tep, -1, "rv", event,
472 ikm_error_handler, NULL);
474 /* ready to enable */
475 tracefs_trace_on(inst->inst);
480 trace_instance_destroy(inst);
488 * ikm_destroy_trace_instance - destroy a previously created instance
490 static void ikm_destroy_trace_instance(struct trace_instance *inst)
495 trace_instance_destroy(inst);
500 * ikm_usage_print_reactors - print all available reactors, one per line.
502 static void ikm_usage_print_reactors(void)
504 char *reactors = tracefs_instance_file_read(NULL, "rv/available_reactors", NULL);
510 fprintf(stderr, " available reactors:");
513 end = strstr(start, "\n");
518 fprintf(stderr, " %s", start);
521 end = strstr(start, "\n");
524 fprintf(stderr, "\n");
527 * ikm_usage - print usage
529 static void ikm_usage(int exit_val, char *monitor_name, const char *fmt, ...)
536 static const char *const usage[] = {
538 " -h/--help: print this menu and the reactor list",
539 " -r/--reactor 'reactor': enables the 'reactor'",
540 " -s/--self: when tracing (-t), also trace rv command",
541 " -t/--trace: trace monitor's event",
542 " -v/--verbose: print debug messages",
548 vsnprintf(message, sizeof(message), fmt, ap);
551 fprintf(stderr, " %s\n", message);
553 fprintf(stderr, "\n usage: rv mon %s [-h] [-q] [-r reactor] [-s] [-v]", monitor_name);
555 for (i = 0; usage[i]; i++)
556 fprintf(stderr, "%s\n", usage[i]);
558 ikm_usage_print_reactors();
563 * parse_arguments - parse arguments and set config
565 static int parse_arguments(char *monitor_name, int argc, char **argv)
569 config_my_pid = getpid();
572 static struct option long_options[] = {
573 {"help", no_argument, 0, 'h'},
574 {"reactor", required_argument, 0, 'r'},
575 {"self", no_argument, 0, 's'},
576 {"trace", no_argument, 0, 't'},
577 {"verbose", no_argument, 0, 'v'},
581 /* getopt_long stores the option index here. */
582 int option_index = 0;
584 c = getopt_long(argc, argv, "hr:stv", long_options, &option_index);
586 /* detect the end of the options. */
592 ikm_usage(0, monitor_name, "help:");
595 config_reactor = optarg;
609 if (config_reactor) {
610 config_initial_reactor = ikm_get_current_reactor(monitor_name);
611 if (!config_initial_reactor)
612 ikm_usage(1, monitor_name,
613 "ikm: failed to read current reactor, are reactors enabled?");
615 retval = ikm_write_reactor(monitor_name, config_reactor);
617 ikm_usage(1, monitor_name,
618 "ikm: failed to set %s reactor, is it available?",
622 debug_msg("ikm: my pid is %d\n", config_my_pid);
628 * ikm_run_monitor - apply configs and run the monitor
630 * Returns 1 if a monitor was found an executed, 0 if no
631 * monitors were found, or -1 on error.
633 int ikm_run_monitor(char *monitor_name, int argc, char **argv)
635 struct trace_instance *inst = NULL;
639 * Check if monitor exists by seeing it is enabled.
641 retval = __ikm_read_enable(monitor_name);
646 err_msg("ikm: monitor %s (in-kernel) is already enabled\n", monitor_name);
650 /* we should be good to go */
651 retval = parse_arguments(monitor_name, argc, argv);
653 ikm_usage(1, monitor_name, "ikm: failed parsing arguments");
656 inst = ikm_setup_trace_instance(monitor_name);
661 retval = ikm_enable(monitor_name);
663 goto out_free_instance;
666 ikm_print_header(inst->seq);
668 while (!should_stop()) {
670 retval = tracefs_iterate_raw_events(inst->tep,
674 collect_registered_events,
677 err_msg("ikm: error reading trace buffer\n");
685 ikm_disable(monitor_name);
686 ikm_destroy_trace_instance(inst);
688 if (config_reactor && config_initial_reactor)
689 ikm_write_reactor(monitor_name, config_initial_reactor);
694 ikm_destroy_trace_instance(inst);
695 if (config_reactor && config_initial_reactor)
696 ikm_write_reactor(monitor_name, config_initial_reactor);