// 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 <[email protected]>
*/
#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 print event.
*/
static int
ikm_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 print event.
*/
static int
ikm_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.
*/
static void ikm_usage_print_reactors(void)
{
char *reactors = tracefs_instance_file_read(NULL, "rv/available_reactors", NULL);
char *start, *end;
if (!reactors)
return;
fprintf(stderr, " available reactors:");
start = reactors;
end = strstr(start, "\n");
while (end) {
*end = '\0';
fprintf(stderr, " %s", start);
start = ++end;
end = strstr(start, "\n");
}
fprintf(stderr, "\n");
}
/*
* ikm_usage - print usage
*/
static void ikm_usage(int exit_val, char *monitor_name, const char *fmt, ...)
{
char message[1024];
va_list ap;
int i;
static const char *const usage[] = {
"",
" -h/--help: print this menu and the reactor list",
" -r/--reactor 'reactor': enables the 'reactor'",
" -s/--self: when tracing (-t), also trace rv command",
" -t/--trace: trace monitor's event",
" -v/--verbose: print debug messages",
"",
NULL,
};
va_start(ap, fmt);
vsnprintf(message, sizeof(message), fmt, ap);
va_end(ap);
fprintf(stderr, " %s\n", message);
fprintf(stderr, "\n usage: rv mon %s [-h] [-q] [-r reactor] [-s] [-v]", monitor_name);
for (i = 0; usage[i]; i++)
fprintf(stderr, "%s\n", usage[i]);
ikm_usage_print_reactors();
exit(exit_val);
}
/*
* parse_arguments - parse arguments and set config
*/
static int parse_arguments(char *monitor_name, int argc, char **argv)
{
int c, retval;
config_my_pid = getpid();
while (1) {
static struct option long_options[] = {
{"help", no_argument, 0, 'h'},
{"reactor", required_argument, 0, 'r'},
{"self", no_argument, 0, 's'},
{"trace", no_argument, 0, 't'},
{"verbose", no_argument, 0, 'v'},
{0, 0, 0, 0}
};
/* getopt_long stores the option index here. */
int option_index = 0;
c = getopt_long(argc, argv, "hr:stv", long_options, &option_index);
/* detect the end of the options. */
if (c == -1)
break;
switch (c) {
case 'h':
ikm_usage(0, monitor_name, "help:");
break;
case 'r':
config_reactor = optarg;
break;
case 's':
config_my_pid = 0;
break;
case 't':
config_trace = 1;
break;
case 'v':
config_debug = 1;
break;
}
}
if (config_reactor) {
config_initial_reactor = ikm_get_current_reactor(monitor_name);
if (!config_initial_reactor)
ikm_usage(1, monitor_name,
"ikm: failed to read current reactor, are reactors enabled?");
retval = ikm_write_reactor(monitor_name, config_reactor);
if (retval <= 0)
ikm_usage(1, monitor_name,
"ikm: failed to set %s reactor, is it available?",
config_reactor);
}
debug_msg("ikm: my pid is %d\n", config_my_pid);
return 0;
}
/**
* ikm_run_monitor - apply configs and run the monitor
*
* Returns 1 if a monitor was found an executed, 0 if no
* monitors were found, or -1 on error.
*/
int ikm_run_monitor(char *monitor_name, int argc, char **argv)
{
struct trace_instance *inst = NULL;
int retval;
/*
* Check if monitor exists by seeing it is enabled.
*/
retval = __ikm_read_enable(monitor_name);
if (retval < 0)
return 0;
if (retval) {
err_msg("ikm: monitor %s (in-kernel) is already enabled\n", monitor_name);
return -1;
}
/* we should be good to go */
retval = parse_arguments(monitor_name, argc, argv);
if (retval)
ikm_usage(1, monitor_name, "ikm: failed parsing arguments");
if (config_trace) {
inst = ikm_setup_trace_instance(monitor_name);
if (!inst)
return -1;
}
retval = ikm_enable(monitor_name);
if (retval < 0)
goto out_free_instance;
if (config_trace)
ikm_print_header(inst->seq);
while (!should_stop()) {
if (config_trace) {
retval = tracefs_iterate_raw_events(inst->tep,
inst->inst,
NULL,
0,
collect_registered_events,
inst);
if (retval) {
err_msg("ikm: error reading trace buffer\n");
break;
}
}
sleep(1);
}
ikm_disable(monitor_name);
ikm_destroy_trace_instance(inst);
if (config_reactor && config_initial_reactor)
ikm_write_reactor(monitor_name, config_initial_reactor);
return 1;
out_free_instance:
ikm_destroy_trace_instance(inst);
if (config_reactor && config_initial_reactor)
ikm_write_reactor(monitor_name, config_initial_reactor);
return -1;
}
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