// SPDX-License-Identifier: GPL-2.0
#define _GNU_SOURCE

#include <pthread.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/sysinfo.h>

#include "common.h"

struct osnoise_tool *trace_tool;
volatile int stop_tracing;
int nr_cpus;

static void stop_trace(int sig)
{
        if (stop_tracing) {
                /*
                 * Stop requested twice in a row; abort event processing and
                 * exit immediately
                 */
                if (trace_tool)
                        tracefs_iterate_stop(trace_tool->trace.inst);
                return;
        }
        stop_tracing = 1;
        if (trace_tool) {
                trace_instance_stop(&trace_tool->trace);
                if (trace_tool->record)
                        trace_instance_stop(&trace_tool->record->trace);
        }
}

/*
 * set_signals - handles the signal to stop the tool
 */
static void set_signals(struct common_params *params)
{
        signal(SIGINT, stop_trace);
        if (params->duration) {
                signal(SIGALRM, stop_trace);
                alarm(params->duration);
        }
}

/*
 * unset_signals - unsets the signals to stop the tool
 */
static void unset_signals(struct common_params *params)
{
        signal(SIGINT, SIG_DFL);
        if (params->duration) {
                alarm(0);
                signal(SIGALRM, SIG_DFL);
        }
}

/*
 * common_apply_config - apply common configs to the initialized tool
 */
int
common_apply_config(struct osnoise_tool *tool, struct common_params *params)
{
        int retval, i;

        if (!params->sleep_time)
                params->sleep_time = 1;

        retval = osnoise_set_cpus(tool->context, params->cpus ? params->cpus : "all");
        if (retval) {
                err_msg("Failed to apply CPUs config\n");
                goto out_err;
        }

        if (!params->cpus) {
                for (i = 0; i < nr_cpus; i++)
                        CPU_SET(i, &params->monitored_cpus);
        }

        if (params->hk_cpus) {
                retval = sched_setaffinity(getpid(), sizeof(params->hk_cpu_set),
                                           &params->hk_cpu_set);
                if (retval == -1) {
                        err_msg("Failed to set rtla to the house keeping CPUs\n");
                        goto out_err;
                }
        } else if (params->cpus) {
                /*
                 * Even if the user do not set a house-keeping CPU, try to
                 * move rtla to a CPU set different to the one where the user
                 * set the workload to run.
                 *
                 * No need to check results as this is an automatic attempt.
                 */
                auto_house_keeping(&params->monitored_cpus);
        }

        /*
         * Set workload according to type of thread if the kernel supports it.
         * On kernels without support, user threads will have already failed
         * on missing fd, and kernel threads do not need it.
         */
        retval = osnoise_set_workload(tool->context, params->kernel_workload);
        if (retval < -1) {
                err_msg("Failed to set OSNOISE_WORKLOAD option\n");
                goto out_err;
        }

        return 0;

out_err:
        return -1;
}


/**
 * common_threshold_handler - handle latency threshold overflow
 * @tool: pointer to the osnoise_tool instance containing trace contexts
 *
 * Executes the configured threshold actions (e.g., saving trace, printing,
 * sending signals). If the continue flag is set (--on-threshold continue),
 * restarts the auxiliary trace instances to continue monitoring.
 *
 * Return: 0 for success, -1 for error.
 */
int
common_threshold_handler(const struct osnoise_tool *tool)
{
        actions_perform(&tool->params->threshold_actions);

        if (!should_continue_tracing(tool->params))
                /* continue flag not set, break */
                return 0;

        /* continue action reached, re-enable tracing */
        if (tool->record && trace_instance_start(&tool->record->trace))
                goto err;
        if (tool->aa && trace_instance_start(&tool->aa->trace))
                goto err;

        return 0;

err:
        err_msg("Error restarting trace\n");
        return -1;
}

int run_tool(struct tool_ops *ops, int argc, char *argv[])
{
        struct common_params *params;
        enum result return_value = ERROR;
        struct osnoise_tool *tool;
        bool stopped;
        int retval;

        nr_cpus = get_nprocs_conf();
        params = ops->parse_args(argc, argv);
        if (!params)
                exit(1);

        tool = ops->init_tool(params);
        if (!tool) {
                err_msg("Could not init osnoise tool\n");
                goto out_exit;
        }
        tool->ops = ops;
        tool->params = params;

        /*
         * Expose the tool to signal handlers so they can stop the trace.
         * Otherwise, rtla could loop indefinitely when overloaded.
         */
        trace_tool = tool;

        retval = ops->apply_config(tool);
        if (retval) {
                err_msg("Could not apply config\n");
                goto out_free;
        }

        retval = enable_tracer_by_name(tool->trace.inst, ops->tracer);
        if (retval) {
                err_msg("Failed to enable %s tracer\n", ops->tracer);
                goto out_free;
        }

        if (params->set_sched) {
                retval = set_comm_sched_attr(ops->comm_prefix, &params->sched_param);
                if (retval) {
                        err_msg("Failed to set sched parameters\n");
                        goto out_free;
                }
        }

        if (params->cgroup && !params->user_data) {
                retval = set_comm_cgroup(ops->comm_prefix, params->cgroup_name);
                if (!retval) {
                        err_msg("Failed to move threads to cgroup\n");
                        goto out_free;
                }
        }


        if (params->threshold_actions.present[ACTION_TRACE_OUTPUT] ||
            params->end_actions.present[ACTION_TRACE_OUTPUT]) {
                tool->record = osnoise_init_trace_tool(ops->tracer);
                if (!tool->record) {
                        err_msg("Failed to enable the trace instance\n");
                        goto out_free;
                }
                params->threshold_actions.trace_output_inst = tool->record->trace.inst;
                params->end_actions.trace_output_inst = tool->record->trace.inst;

                if (params->events) {
                        retval = trace_events_enable(&tool->record->trace, params->events);
                        if (retval)
                                goto out_trace;
                }

                if (params->buffer_size > 0) {
                        retval = trace_set_buffer_size(&tool->record->trace, params->buffer_size);
                        if (retval)
                                goto out_trace;
                }
        }

        if (params->user_workload) {
                pthread_t user_thread;

                /* rtla asked to stop */
                params->user.should_run = 1;
                /* all threads left */
                params->user.stopped_running = 0;

                params->user.set = &params->monitored_cpus;
                if (params->set_sched)
                        params->user.sched_param = &params->sched_param;
                else
                        params->user.sched_param = NULL;

                params->user.cgroup_name = params->cgroup_name;

                retval = pthread_create(&user_thread, NULL, timerlat_u_dispatcher, &params->user);
                if (retval) {
                        err_msg("Error creating timerlat user-space threads\n");
                        goto out_trace;
                }
        }

        retval = ops->enable(tool);
        if (retval)
                goto out_trace;

        tool->start_time = time(NULL);
        set_signals(params);

        retval = ops->main(tool);
        if (retval)
                goto out_signals;

        if (params->user_workload && !params->user.stopped_running) {
                params->user.should_run = 0;
                sleep(1);
        }

        ops->print_stats(tool);

        actions_perform(&params->end_actions);

        return_value = PASSED;

        stopped = osnoise_trace_is_off(tool, tool->record) && !stop_tracing;
        if (stopped) {
                printf("%s hit stop tracing\n", ops->tracer);
                return_value = FAILED;
        }

        if (ops->analyze)
                ops->analyze(tool, stopped);

out_signals:
        unset_signals(params);
out_trace:
        trace_events_destroy(&tool->record->trace, params->events);
        params->events = NULL;
out_free:
        ops->free(tool);
        osnoise_destroy_tool(tool->record);
        osnoise_destroy_tool(tool);
        actions_destroy(&params->threshold_actions);
        actions_destroy(&params->end_actions);
        free(params);
out_exit:
        exit(return_value);
}

int top_main_loop(struct osnoise_tool *tool)
{
        struct common_params *params = tool->params;
        struct trace_instance *trace = &tool->trace;
        struct osnoise_tool *record = tool->record;
        int retval;

        while (!stop_tracing) {
                sleep(params->sleep_time);

                if (params->aa_only && !osnoise_trace_is_off(tool, record))
                        continue;

                retval = tracefs_iterate_raw_events(trace->tep,
                                                    trace->inst,
                                                    NULL,
                                                    0,
                                                    collect_registered_events,
                                                    trace);
                if (retval < 0) {
                        err_msg("Error iterating on events\n");
                        return retval;
                }

                if (!params->quiet)
                        tool->ops->print_stats(tool);

                if (osnoise_trace_is_off(tool, record)) {
                        if (stop_tracing)
                                /* stop tracing requested, do not perform actions */
                                return 0;

                        retval = common_threshold_handler(tool);
                        if (retval)
                                return retval;


                        if (!should_continue_tracing(params))
                                return 0;

                        trace_instance_start(trace);
                }

                /* is there still any user-threads ? */
                if (params->user_workload) {
                        if (params->user.stopped_running) {
                                debug_msg("timerlat user space threads stopped!\n");
                                break;
                        }
                }
        }

        return 0;
}

int hist_main_loop(struct osnoise_tool *tool)
{
        struct common_params *params = tool->params;
        struct trace_instance *trace = &tool->trace;
        int retval = 0;

        while (!stop_tracing) {
                sleep(params->sleep_time);

                retval = tracefs_iterate_raw_events(trace->tep,
                                                    trace->inst,
                                                    NULL,
                                                    0,
                                                    collect_registered_events,
                                                    trace);
                if (retval < 0) {
                        err_msg("Error iterating on events\n");
                        break;
                }

                if (osnoise_trace_is_off(tool, tool->record)) {
                        if (stop_tracing)
                                /* stop tracing requested, do not perform actions */
                                break;

                        retval = common_threshold_handler(tool);
                        if (retval)
                                return retval;

                        if (!should_continue_tracing(params))
                                return 0;

                        trace_instance_start(trace);
                }

                /* is there still any user-threads ? */
                if (params->user_workload) {
                        if (params->user.stopped_running) {
                                debug_msg("user-space threads stopped!\n");
                                break;
                        }
                }
        }

        return retval;
}

int osn_set_stop(struct osnoise_tool *tool)
{
        struct common_params *params = tool->params;
        int retval;

        retval = osnoise_set_stop_us(tool->context, params->stop_us);
        if (retval) {
                err_msg("Failed to set stop us\n");
                return retval;
        }

        retval = osnoise_set_stop_total_us(tool->context, params->stop_total_us);
        if (retval) {
                err_msg("Failed to set stop total us\n");
                return retval;
        }

        return 0;
}

static void print_msg_array(const char * const *msgs)
{
        if (!msgs)
                return;

        for (int i = 0; msgs[i]; i++)
                fprintf(stderr, "%s\n", msgs[i]);
}

/*
 * common_usage - print complete usage information
 */
void common_usage(const char *tool, const char *mode,
                  const char *desc, const char * const *start_msgs, const char * const *opt_msgs)
{
        static const char * const common_options[] = {
                "         -h/--help: print this menu",
                NULL
        };
        fprintf(stderr, "rtla %s", tool);
        if (strcmp(mode, ""))
                fprintf(stderr, " %s", mode);
        fprintf(stderr, ": %s (version %s)\n\n", desc, VERSION);
        fprintf(stderr, "  usage: [rtla] %s ", tool);

        if (strcmp(mode, "top") == 0)
                fprintf(stderr, "[top] [-h] ");
        else
                fprintf(stderr, "%s [-h] ", mode);

        print_msg_array(start_msgs);
        fprintf(stderr, "\n");
        print_msg_array(common_options);
        print_msg_array(opt_msgs);

        exit(EXIT_SUCCESS);
}