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// SPDX-License-Identifier: GPL-2.0/* * in kernel monitor support: allows rv to control in-kernel monitors. * * Copyright (C) 2022 Red Hat Inc, Daniel Bristot de Oliveira <bristot@kernel.org> */#include <getopt.h>#include <stdlib.h>#include <string.h>#include <errno.h>#include <unistd.h> #include <trace.h>#include <utils.h>#include <rv.h> static int config_has_id;static int config_my_pid;static int config_trace; static char *config_initial_reactor;static char *config_reactor; /* * __ikm_read_enable - reads monitor's enable status * * __does not log errors. * * Returns the current status, or -1 if the monitor does not exist, * __hence not logging errors. */static int __ikm_read_enable(char *monitor_name){	char path[MAX_PATH];	long long enabled;	int retval; 	snprintf(path, MAX_PATH, "rv/monitors/%s/enable", monitor_name); 	retval = tracefs_instance_file_read_number(NULL, path, &enabled);	if (retval < 0)		return -1; 	return enabled;} /* * ikm_read_enable - reads monitor's enable status * * Returns the current status, or -1 on error. */static int ikm_read_enable(char *monitor_name){	int enabled; 	enabled = __ikm_read_enable(monitor_name);	if (enabled < 0) {		err_msg("ikm: fail read enabled: %d\n", enabled);		return -1;	} 	debug_msg("ikm: read enabled: %d\n", enabled); 	return enabled;} /* * ikm_write_enable - write to the monitor's enable file * * Return the number of bytes written, -1 on error. */static int ikm_write_enable(char *monitor_name, char *enable_disable){	char path[MAX_PATH];	int retval; 	debug_msg("ikm: writing enabled: %s\n", enable_disable); 	snprintf(path, MAX_PATH, "rv/monitors/%s/enable", monitor_name);	retval = tracefs_instance_file_write(NULL, path, enable_disable);	if (retval < strlen(enable_disable)) {		err_msg("ikm: writing enabled: %s\n", enable_disable);		return -1;	} 	return retval;} /* * ikm_enable - enable a monitor * * Returns -1 on failure. Success otherwise. */static int ikm_enable(char *monitor_name){	return ikm_write_enable(monitor_name, "1");} /* * ikm_disable - disable a monitor * * Returns -1 on failure. Success otherwise. */static int ikm_disable(char *monitor_name){	return ikm_write_enable(monitor_name, "0");} /* * ikm_read_desc - read monitors' description * * Return a dynamically allocated string with the monitor's * description, NULL otherwise. */static char *ikm_read_desc(char *monitor_name){	char path[MAX_PATH];	char *desc; 	snprintf(path, MAX_PATH, "rv/monitors/%s/desc", monitor_name);	desc = tracefs_instance_file_read(NULL, path, NULL);	if (!desc) {		err_msg("ikm: error reading monitor %s desc\n", monitor_name);		return NULL;	} 	*strstr(desc, "\n") = '\0'; 	return desc;} /* * ikm_fill_monitor_definition - fill monitor's definition * * Returns -1 on error, 0 otherwise. */static int ikm_fill_monitor_definition(char *name, struct monitor *ikm){	int enabled;	char *desc; 	enabled = ikm_read_enable(name);	if (enabled < 0) {		err_msg("ikm: monitor %s fail to read enable file, bug?\n", name);		return -1;	} 	desc = ikm_read_desc(name);	if (!desc) {		err_msg("ikm: monitor %s does not have desc file, bug?\n", name);		return -1;	} 	strncpy(ikm->name, name, MAX_DA_NAME_LEN);	ikm->enabled = enabled;	strncpy(ikm->desc, desc, MAX_DESCRIPTION); 	free(desc); 	return 0;} /* * ikm_write_reactor - switch the reactor to *reactor * * Return the number or characters written, -1 on error. */static int ikm_write_reactor(char *monitor_name, char *reactor){	char path[MAX_PATH];	int retval; 	snprintf(path, MAX_PATH, "rv/monitors/%s/reactors", monitor_name);	retval = tracefs_instance_file_write(NULL, path, reactor);	debug_msg("ikm: write \"%s\" reactors: %d\n", reactor, retval); 	return retval;} /* * ikm_read_reactor - read the reactors file * * Returns a dynamically allocated string with monitor's * available reactors, or NULL on error. */static char *ikm_read_reactor(char *monitor_name){	char path[MAX_PATH];	char *reactors; 	snprintf(path, MAX_PATH, "rv/monitors/%s/reactors", monitor_name);	reactors = tracefs_instance_file_read(NULL, path, NULL);	if (!reactors) {		err_msg("ikm: fail reading monitor's %s reactors file\n", monitor_name);		return NULL;	} 	return reactors;} /* * ikm_get_current_reactor - get the current enabled reactor * * Reads the reactors file and find the currently enabled * [reactor]. * * Returns a dynamically allocated memory with the current * reactor. NULL otherwise. */static char *ikm_get_current_reactor(char *monitor_name){	char *reactors = ikm_read_reactor(monitor_name);	char *curr_reactor = NULL;	char *start;	char *end; 	if (!reactors)		return NULL; 	start = strstr(reactors, "[");	if (!start)		goto out_free; 	start++; 	end = strstr(start, "]");	if (!end)		goto out_free; 	*end = '\0'; 	curr_reactor = calloc(strlen(start) + 1, sizeof(char));	if (!curr_reactor)		goto out_free; 	strncpy(curr_reactor, start, strlen(start));	debug_msg("ikm: read current reactor %s\n", curr_reactor); out_free:	free(reactors); 	return curr_reactor;} static int ikm_has_id(char *monitor_name){	char path[MAX_PATH];	char *format;	int has_id; 	snprintf(path, MAX_PATH, "events/rv/event_%s/format", monitor_name);	format = tracefs_instance_file_read(NULL, path, NULL);	if (!format) {		err_msg("ikm: fail reading monitor's %s format event file\n", monitor_name);		return -1;	} 	/* print fmt: "%d: %s x %s -> %s %s", REC->id, ... */	has_id = !!strstr(format, "REC->id"); 	debug_msg("ikm: monitor %s has id: %s\n", monitor_name, has_id ? "yes" : "no"); 	free(format); 	return has_id;} /** * ikm_list_monitors - list all available monitors * * Returns 0 on success, -1 otherwise. */int ikm_list_monitors(void){	char *available_monitors;	struct monitor ikm;	char *curr, *next;	int retval; 	available_monitors = tracefs_instance_file_read(NULL, "rv/available_monitors", NULL); 	if (!available_monitors) {		err_msg("ikm: available monitors is not available, is CONFIG_RV enabled?\n");		return -1;	} 	curr = available_monitors;	do {		next = strstr(curr, "\n");		*next = '\0'; 		retval = ikm_fill_monitor_definition(curr, &ikm);		if (retval)			err_msg("ikm: error reading %d in kernel monitor, skipping\n", curr); 		printf("%-24s %s %s\n", ikm.name, ikm.desc, ikm.enabled ? "[ON]" : "[OFF]");		curr = ++next; 	} while (strlen(curr)); 	free(available_monitors); 	return 0;} static void ikm_print_header(struct trace_seq *s){	trace_seq_printf(s, "%16s-%-8s %5s %5s ", "<TASK>", "PID", "[CPU]", "TYPE");	if (config_has_id)		trace_seq_printf(s, "%8s ", "ID"); 	trace_seq_printf(s, "%24s x %-24s -> %-24s %s\n",			 "STATE",			 "EVENT",			 "NEXT_STATE",			 "FINAL"); 	trace_seq_printf(s, "%16s %-8s %5s %5s ", " | ", " | ", " | ", " | "); 	if (config_has_id)		trace_seq_printf(s, "%8s ", " | "); 	trace_seq_printf(s, "%24s   %-24s    %-24s %s\n",			 " | ",			 " | ",			 " | ",			 "|"); } /* * ikm_event_handler - callback to handle event events * * Called any time a rv:"monitor"_event events is generated. * It parses and prints event. */static intikm_event_handler(struct trace_seq *s, struct tep_record *record,		  struct tep_event *trace_event, void *context){	/* if needed: struct trace_instance *inst = context; */	char *state, *event, *next_state;	unsigned long long final_state;	unsigned long long pid;	unsigned long long id;	int cpu = record->cpu;	int val; 	if (config_has_id)		tep_get_field_val(s, trace_event, "id", record, &id, 1); 	tep_get_common_field_val(s, trace_event, "common_pid", record, &pid, 1); 	if (config_has_id && (config_my_pid == id))		return 0;	else if (config_my_pid && (config_my_pid == pid))		return 0; 	tep_print_event(trace_event->tep, s, record, "%16s-%-8d ", TEP_PRINT_COMM, TEP_PRINT_PID); 	trace_seq_printf(s, "[%.3d] event ", cpu); 	if (config_has_id)		trace_seq_printf(s, "%8llu ", id); 	state = tep_get_field_raw(s, trace_event, "state", record, &val, 0);	event = tep_get_field_raw(s, trace_event, "event", record, &val, 0);	next_state = tep_get_field_raw(s, trace_event, "next_state", record, &val, 0);	tep_get_field_val(s, trace_event, "final_state", record, &final_state, 1); 	trace_seq_printf(s, "%24s x %-24s -> %-24s %s\n",			 state,			 event,			 next_state,			 final_state ? "Y" : "N"); 	trace_seq_do_printf(s);	trace_seq_reset(s); 	return 0;} /* * ikm_error_handler - callback to handle error events * * Called any time a rv:"monitor"_errors events is generated. * It parses and prints event. */static intikm_error_handler(struct trace_seq *s, struct tep_record *record,		  struct tep_event *trace_event, void *context){	unsigned long long pid, id;	int cpu = record->cpu;	char *state, *event;	int val; 	if (config_has_id)		tep_get_field_val(s, trace_event, "id", record, &id, 1); 	tep_get_common_field_val(s, trace_event, "common_pid", record, &pid, 1); 	if (config_has_id && config_my_pid == id)		return 0;	else if (config_my_pid == pid)		return 0; 	trace_seq_printf(s, "%8lld [%03d] error ", pid, cpu); 	if (config_has_id)		trace_seq_printf(s, "%8llu ", id); 	state = tep_get_field_raw(s, trace_event, "state", record, &val, 0);	event = tep_get_field_raw(s, trace_event, "event", record, &val, 0); 	trace_seq_printf(s, "%24s x %s\n", state, event); 	trace_seq_do_printf(s);	trace_seq_reset(s); 	return 0;} /* * ikm_setup_trace_instance - set up a tracing instance to collect data * * Create a trace instance, enable rv: events and enable the trace. * * Returns the trace_instance * with all set, NULL otherwise. */static struct trace_instance *ikm_setup_trace_instance(char *monitor_name){	char event[MAX_DA_NAME_LEN + 7]; /* max(error_,event_) + '0' = 7 */	struct trace_instance *inst;	int retval; 	if (!config_trace)		return NULL; 	config_has_id = ikm_has_id(monitor_name);	if (config_has_id < 0) {		err_msg("ikm: failed to read monitor %s event format\n", monitor_name);		goto out_err;	} 	/* alloc data */	inst = calloc(1, sizeof(*inst));	if (!inst) {		err_msg("ikm: failed to allocate trace instance");		goto out_err;	} 	retval = trace_instance_init(inst, monitor_name);	if (retval)		goto out_free; 	/* enable events */	snprintf(event, sizeof(event), "event_%s", monitor_name);	retval = tracefs_event_enable(inst->inst, "rv",  event);	if (retval)		goto out_inst; 	tep_register_event_handler(inst->tep, -1, "rv", event,				   ikm_event_handler, NULL); 	snprintf(event, sizeof(event), "error_%s", monitor_name);	retval = tracefs_event_enable(inst->inst, "rv", event);	if (retval)		goto out_inst; 	tep_register_event_handler(inst->tep, -1, "rv", event,				   ikm_error_handler, NULL); 	/* ready to enable */	tracefs_trace_on(inst->inst); 	return inst; out_inst:	trace_instance_destroy(inst);out_free:	free(inst);out_err:	return NULL;} /** * ikm_destroy_trace_instance - destroy a previously created instance */static void ikm_destroy_trace_instance(struct trace_instance *inst){	if (!inst)		return; 	trace_instance_destroy(inst);	free(inst);} /* * ikm_usage_print_reactors - print all available reactors, one per line.

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