1 // SPDX-License-Identifier: GPL-2.0
3  * in kernel monitor support: allows rv to control in-kernel monitors.
13 #include <trace.h>
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
29  * Returns the current status, or -1 if the monitor does not exist,
32 static int __ikm_read_enable(char *monitor_name)  in __ikm_read_enable()
42 		return -1;  in __ikm_read_enable()
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)  in ikm_read_enable()
59 		return -1;  in ikm_read_enable()
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)  in ikm_write_enable()
83 		return -1;  in ikm_write_enable()
90  * ikm_enable - enable a monitor
92  * Returns -1 on failure. Success otherwise.
94 static int ikm_enable(char *monitor_name)  in ikm_enable()
100  * ikm_disable - disable a monitor
102  * Returns -1 on failure. Success otherwise.
104 static int ikm_disable(char *monitor_name)  in ikm_disable()
110  * ikm_read_desc - read monitors' description
115 static char *ikm_read_desc(char *monitor_name)  in ikm_read_desc()
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)  in ikm_fill_monitor_definition()
145 		return -1;  in ikm_fill_monitor_definition()
151 		return -1;  in ikm_fill_monitor_definition()
154 	strncpy(ikm->name, name, MAX_DA_NAME_LEN);  in ikm_fill_monitor_definition()
155 	ikm->enabled = enabled;  in ikm_fill_monitor_definition()
156 	strncpy(ikm->desc, desc, MAX_DESCRIPTION);  in ikm_fill_monitor_definition()
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)  in ikm_write_reactor()
181  * ikm_read_reactor - read the reactors file
186 static char *ikm_read_reactor(char *monitor_name)  in ikm_read_reactor()
202  * ikm_get_current_reactor - get the current enabled reactor
210 static char *ikm_get_current_reactor(char *monitor_name)  in ikm_get_current_reactor()
245 static int ikm_has_id(char *monitor_name)  in ikm_has_id()
255 		return -1;  in ikm_has_id()
258 	/* print fmt: "%d: %s x %s -> %s %s", REC->id, ... */  in ikm_has_id()
259 	has_id = !!strstr(format, "REC->id");  in ikm_has_id()
261 	debug_msg("ikm: monitor %s has id: %s\n", monitor_name, has_id ? "yes" : "no");  in ikm_has_id()
269  * ikm_list_monitors - list all available monitors
271  * Returns 0 on success, -1 otherwise.
284 		return -1;  in ikm_list_monitors()
296 		printf("%-24s %s %s\n", ikm.name, ikm.desc, ikm.enabled ? "[ON]" : "[OFF]");  in ikm_list_monitors()
306 static void ikm_print_header(struct trace_seq *s)  in ikm_print_header()
308 	trace_seq_printf(s, "%16s-%-8s %5s %5s ", "<TASK>", "PID", "[CPU]", "TYPE");  in ikm_print_header()
310 		trace_seq_printf(s, "%8s ", "ID");  in ikm_print_header()
312 	trace_seq_printf(s, "%24s x %-24s -> %-24s %s\n",  in ikm_print_header()
318 	trace_seq_printf(s, "%16s %-8s %5s %5s ", " | ", " | ", " | ", " | ");  in ikm_print_header()
323 	trace_seq_printf(s, "%24s   %-24s    %-24s %s\n",  in ikm_print_header()
332  * ikm_event_handler - callback to handle event events
337 static int
345 	unsigned long long id;  in ikm_event_handler()  local
346 	int cpu = record->cpu;  in ikm_event_handler()
350 		tep_get_field_val(s, trace_event, "id", record, &id, 1);  in ikm_event_handler()
354 	if (config_has_id && (config_my_pid == id))  in ikm_event_handler()
359 	tep_print_event(trace_event->tep, s, record, "%16s-%-8d ", TEP_PRINT_COMM, TEP_PRINT_PID);  in ikm_event_handler()
364 		trace_seq_printf(s, "%8llu ", id);  in ikm_event_handler()
371 	trace_seq_printf(s, "%24s x %-24s -> %-24s %s\n",  in ikm_event_handler()
384  * ikm_error_handler - callback to handle error events
389 static int
393 	unsigned long long pid, id;  in ikm_error_handler()  local
394 	int cpu = record->cpu;  in ikm_error_handler()
399 		tep_get_field_val(s, trace_event, "id", record, &id, 1);  in ikm_error_handler()
403 	if (config_has_id && config_my_pid == id)  in ikm_error_handler()
411 		trace_seq_printf(s, "%8llu ", id);  in ikm_error_handler()
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.
431 static struct trace_instance *ikm_setup_trace_instance(char *monitor_name)  in ikm_setup_trace_instance()
449 		err_msg("ikm: failed to allocate trace instance");  in ikm_setup_trace_instance()
459 	retval = tracefs_event_enable(inst->inst, "rv",  event);  in ikm_setup_trace_instance()
463 	tep_register_event_handler(inst->tep, -1, "rv", event,  in ikm_setup_trace_instance()
467 	retval = tracefs_event_enable(inst->inst, "rv", event);  in ikm_setup_trace_instance()
471 	tep_register_event_handler(inst->tep, -1, "rv", event,  in ikm_setup_trace_instance()
475 	tracefs_trace_on(inst->inst);  in ikm_setup_trace_instance()
488  * ikm_destroy_trace_instance - destroy a previously created instance
490 static void ikm_destroy_trace_instance(struct trace_instance *inst)  in ikm_destroy_trace_instance()
500  * ikm_usage_print_reactors - print all available reactors, one per line.
502 static void ikm_usage_print_reactors(void)  in ikm_usage_print_reactors()
527  * ikm_usage - print usage
529 static void ikm_usage(int exit_val, char *monitor_name, const char *fmt, ...)  in ikm_usage()
536 	static const char *const usage[] = {  in ikm_usage()
538 		"	-h/--help: print this menu and the reactor list",  in ikm_usage()
539 		"	-r/--reactor 'reactor': enables the 'reactor'",  in ikm_usage()
540 		"	-s/--self: when tracing (-t), also trace rv command",  in ikm_usage()
541 		"	-t/--trace: trace monitor's event",  in ikm_usage()
542 		"	-v/--verbose: print debug messages",  in ikm_usage()
553 	fprintf(stderr, "\n  usage: rv mon %s [-h] [-q] [-r reactor] [-s] [-v]", monitor_name);  in ikm_usage()
563  * parse_arguments - parse arguments and set config
565 static int parse_arguments(char *monitor_name, int argc, char **argv)  in parse_arguments()
572 		static struct option long_options[] = {  in parse_arguments()
576 			{"trace",		no_argument,		0, 't'},  in parse_arguments()
587 		if (c == -1)  in parse_arguments()
628  * ikm_run_monitor - apply configs and run the monitor
631  * monitors were found, or -1 on error.
646 		err_msg("ikm: monitor %s (in-kernel) is already enabled\n", monitor_name);  in ikm_run_monitor()
647 		return -1;  in ikm_run_monitor()
658 			return -1;  in ikm_run_monitor()
666 		ikm_print_header(inst->seq);  in ikm_run_monitor()
670 			retval = tracefs_iterate_raw_events(inst->tep,  in ikm_run_monitor()
671 							    inst->inst,  in ikm_run_monitor()
677 				err_msg("ikm: error reading trace buffer\n");  in ikm_run_monitor()
697 	return -1;  in ikm_run_monitor()