/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2018, Matthew Macy
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 */

#include <sys/param.h>
#include <sys/cpuset.h>
#include <sys/event.h>
#include <sys/queue.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/sysctl.h>
#include <sys/time.h>
#include <sys/ttycom.h>
#include <sys/user.h>
#include <sys/wait.h>

#include <assert.h>
#include <curses.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <getopt.h>
#include <kvm.h>
#include <libgen.h>
#include <limits.h>
#include <locale.h>
#include <math.h>
#include <pmc.h>
#include <pmclog.h>
#include <regex.h>
#include <signal.h>
#include <stdarg.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <unistd.h>

#include <libpmcstat.h>
#include "cmd_pmc.h"

/*
 * Return the frequency of the kernel's statistics clock.
 */
static int
getstathz(void)
{
        int mib[2];
        size_t size;
        struct clockinfo clockrate;

        mib[0] = CTL_KERN;
        mib[1] = KERN_CLOCKRATE;
        size = sizeof clockrate;
        if (sysctl(mib, 2, &clockrate, &size, NULL, 0) == -1)
                err(1, "sysctl kern.clockrate");
        return clockrate.stathz;
}

#define STAT_MODE_NPMCS 6
#define FIXED_MODE_NPMCS 2
static struct timespec before_ts;
#define CYCLES          0
#define INST            1
#define BR              2
#define IAP_START       BR
#define BR_MISS 3
#define CACHE   4
#define CACHE_MISS      5
static const char *pmc_stat_mode_names[] = {
        "cycles",
        "instructions",
        "branches",
        "branch-misses",
        "cache-references",
        "cache-misses",
};

/* Common aliases for the desired stat counter */
static const char *pmc_stat_mode_aliases[] = {
        "unhalted-cycles",
        "instructions",
        "branches",
        "branch-mispredicts",
        "LLC-REFERENCE",
        "LLC-MISSES",
};

static int pmcstat_sockpair[NSOCKPAIRFD];

static void __dead2
usage(void)
{
        errx(EX_USAGE,
            "\t get basic stats from command line program\n"
            "\t -j <eventlist>, --events <eventlist> comma-delimited list of event specifiers\n"
            );
}

static void
showtime(FILE *out, struct timespec *before, struct timespec *after,
    struct rusage *ru)
{
        char decimal_point;
        uint64_t real, user, sys;

        (void)setlocale(LC_NUMERIC, "");
        decimal_point = localeconv()->decimal_point[0];

        after->tv_sec -= before->tv_sec;
        after->tv_nsec -= before->tv_nsec;
        if (after->tv_nsec < 0) {
                after->tv_sec--;
                after->tv_nsec += 1000000000;
        }

        real = (after->tv_sec * 1000000000 + after->tv_nsec) / 1000;
        user = ru->ru_utime.tv_sec * 1000000 + ru->ru_utime.tv_usec;
        sys = ru->ru_stime.tv_sec * 1000000 + ru->ru_stime.tv_usec;
        fprintf(out, "%13jd%c%02ld  real\t\t\t#\t%2.02f%% cpu\n",
            (intmax_t)after->tv_sec, decimal_point,
            after->tv_nsec / 10000000, 100 * (double)(sys + user + 1) / (double)(real + 1));
        fprintf(out, "%13jd%c%02ld  user\t\t\t#\t%2.2f%% cpu\n",
            (intmax_t)ru->ru_utime.tv_sec, decimal_point,
            ru->ru_utime.tv_usec / 10000, 100 * (double)(user + 1) / (double)(real + 1));
        fprintf(out, "%13jd%c%02ld  sys\t\t\t#\t%2.02f%% cpu\n",
            (intmax_t)ru->ru_stime.tv_sec, decimal_point,
            ru->ru_stime.tv_usec / 10000, 100 * (double)(sys + 1) / (double)(real + 1));
}

static const char *stat_mode_cntrs[STAT_MODE_NPMCS];
static const char *stat_mode_names[STAT_MODE_NPMCS];

static void
pmc_stat_setup_stat(int system_mode, const char *arg)
{
        const char *new_cntrs[STAT_MODE_NPMCS];
        struct pmcstat_ev *ev;
        char *counters, *counter;
        int i, c, start, newcnt;
        cpuset_t cpumask, rootmask;

        if (cpuset_getaffinity(CPU_LEVEL_ROOT, CPU_WHICH_PID, -1,
            sizeof(rootmask), &rootmask) == -1)
                err(EX_OSERR, "ERROR: Cannot determine the root set of CPUs");
        CPU_COPY(&rootmask, &cpumask);

        if (system_mode && geteuid() != 0)
                errx(EX_USAGE, "ERROR: system mode counters can only be used as root");
        counters = NULL;
        for (i = 0; i < STAT_MODE_NPMCS; i++) {
                stat_mode_cntrs[i] = pmc_stat_mode_aliases[i];
                stat_mode_names[i] = pmc_stat_mode_names[i];
        }
        if (arg) {
                counters = strdup(arg);
                newcnt = 0;
                while ((counter = strsep(&counters, ",")) != NULL &&
                    newcnt < STAT_MODE_NPMCS - IAP_START) {
                        new_cntrs[newcnt++] = counter;
                        if (pmc_pmu_sample_rate_get(counter) == DEFAULT_SAMPLE_COUNT)
                                errx(EX_USAGE, "ERROR: %s not recognized on host", counter);
                }
                start = IAP_START + STAT_MODE_NPMCS - FIXED_MODE_NPMCS - newcnt;
                for (i = 0; i < newcnt; i++) {
                        stat_mode_cntrs[start + i] = new_cntrs[i];
                        stat_mode_names[start + i] = new_cntrs[i];
                }
        }
        if (system_mode)
                pmc_args.pa_flags |= FLAG_HAS_SYSTEM_PMCS;
        else
                pmc_args.pa_flags |= FLAG_HAS_PROCESS_PMCS;
        pmc_args.pa_flags |= FLAG_HAS_COUNTING_PMCS;
        pmc_args.pa_flags |= FLAG_HAS_COMMANDLINE | FLAG_HAS_TARGET;
        pmc_args.pa_flags |= FLAG_HAS_PIPE;
        pmc_args.pa_required |= FLAG_HAS_COMMANDLINE | FLAG_HAS_TARGET | FLAG_HAS_OUTPUT_LOGFILE;
        pmc_args.pa_outputpath = strdup("/dev/null");
        pmc_args.pa_logfd = pmcstat_open_log(pmc_args.pa_outputpath,
            PMCSTAT_OPEN_FOR_WRITE);
        for (i = 0; i < STAT_MODE_NPMCS; i++) {
                if ((ev = malloc(sizeof(*ev))) == NULL)
                        errx(EX_SOFTWARE, "ERROR: Out of memory.");
                if (system_mode)
                        ev->ev_mode = PMC_MODE_SC;
                else
                        ev->ev_mode = PMC_MODE_TC;
                ev->ev_spec = strdup(stat_mode_cntrs[i]);
                if (ev->ev_spec == NULL)
                        errx(EX_SOFTWARE, "ERROR: Out of memory.");
                c = strcspn(strdup(stat_mode_cntrs[i]), ", \t");
                ev->ev_name = malloc(c + 1);
                if (ev->ev_name == NULL)
                        errx(EX_SOFTWARE, "ERROR: Out of memory.");
                (void)strncpy(ev->ev_name, stat_mode_cntrs[i], c);
                *(ev->ev_name + c) = '\0';

                ev->ev_count = -1;
                ev->ev_flags = 0;
                ev->ev_flags |= PMC_F_DESCENDANTS;
                ev->ev_cumulative = 1;

                ev->ev_saved = 0LL;
                ev->ev_pmcid = PMC_ID_INVALID;
                STAILQ_INSERT_TAIL(&pmc_args.pa_events, ev, ev_next);
                if (system_mode) {
                        ev->ev_cpu = CPU_FFS(&cpumask) - 1;
                        CPU_CLR(ev->ev_cpu, &cpumask);
                        pmcstat_clone_event_descriptor(ev, &cpumask, &pmc_args);
                        CPU_SET(ev->ev_cpu, &cpumask);
                } else
                        ev->ev_cpu = PMC_CPU_ANY;

        }
        if (clock_gettime(CLOCK_MONOTONIC, &before_ts))
                err(1, "clock_gettime");
}

static void
pmc_stat_print_stat(struct rusage *ru)
{
        struct pmcstat_ev *ev;
        struct timespec after;
        uint64_t cvals[STAT_MODE_NPMCS];
        uint64_t ticks, value;
        int hz, i;

        if (ru) {
                hz = getstathz();
                ticks = hz * (ru->ru_utime.tv_sec + ru->ru_stime.tv_sec) +
                        hz * (ru->ru_utime.tv_usec + ru->ru_stime.tv_usec) / 1000000;
                if (clock_gettime(CLOCK_MONOTONIC, &after))
                        err(1, "clock_gettime");
                /*
                 * If our round-off on the tick calculation still puts us at 0,
                 * then always assume at least one tick.
                 */
                if (ticks == 0)
                        ticks = 1;
                fprintf(pmc_args.pa_printfile, "%16ld  %s\t\t#\t%02.03f M/sec\n",
                        ru->ru_minflt, "page faults", ((double)ru->ru_minflt / (double)ticks) / hz);
                fprintf(pmc_args.pa_printfile, "%16ld  %s\t\t#\t%02.03f M/sec\n",
                        ru->ru_nvcsw, "voluntary csw", ((double)ru->ru_nvcsw / (double)ticks) / hz);
                fprintf(pmc_args.pa_printfile, "%16ld  %s\t#\t%02.03f M/sec\n",
                        ru->ru_nivcsw, "involuntary csw", ((double)ru->ru_nivcsw / (double)ticks) / hz);
        }

        bzero(&cvals, sizeof(cvals));
        STAILQ_FOREACH(ev, &pmc_args.pa_events, ev_next) {
                if (pmc_read(ev->ev_pmcid, &value) < 0)
                        err(EX_OSERR, "ERROR: Cannot read pmc \"%s\"",
                            ev->ev_name);
                for (i = 0; i < STAT_MODE_NPMCS; i++)
                        if (strcmp(ev->ev_name, stat_mode_cntrs[i]) == 0)
                                cvals[i] += value;
        }

        fprintf(pmc_args.pa_printfile, "%16jd  %s\n", (uintmax_t)cvals[CYCLES], stat_mode_names[CYCLES]);
        fprintf(pmc_args.pa_printfile, "%16jd  %s\t\t#\t%01.03f inst/cycle\n", (uintmax_t)cvals[INST], stat_mode_names[INST],
            (double)cvals[INST] / cvals[CYCLES]);
        fprintf(pmc_args.pa_printfile, "%16jd  %s\n", (uintmax_t)cvals[BR], stat_mode_names[BR]);
        if (stat_mode_names[BR_MISS] == pmc_stat_mode_names[BR_MISS])
                fprintf(pmc_args.pa_printfile, "%16jd  %s\t\t#\t%.03f%%\n",
                    (uintmax_t)cvals[BR_MISS], stat_mode_names[BR_MISS],
                    100 * ((double)cvals[BR_MISS] / cvals[BR]));
        else
                fprintf(pmc_args.pa_printfile, "%16jd  %s\n",
                    (uintmax_t)cvals[BR_MISS], stat_mode_names[BR_MISS]);
        fprintf(pmc_args.pa_printfile, "%16jd  %s%s", (uintmax_t)cvals[CACHE], stat_mode_names[CACHE],
            stat_mode_names[CACHE] != pmc_stat_mode_names[CACHE] ? "\n" : "");
        if (stat_mode_names[CACHE] == pmc_stat_mode_names[CACHE])
                fprintf(pmc_args.pa_printfile, "\t#\t%.03f refs/inst\n",
                    ((double)cvals[CACHE] / cvals[INST]));
        fprintf(pmc_args.pa_printfile, "%16jd  %s%s", (uintmax_t)cvals[CACHE_MISS], stat_mode_names[CACHE_MISS],
            stat_mode_names[CACHE_MISS] != pmc_stat_mode_names[CACHE_MISS] ? "\n" : "");
        if (stat_mode_names[CACHE_MISS] == pmc_stat_mode_names[CACHE_MISS])
                fprintf(pmc_args.pa_printfile, "\t\t#\t%.03f%%\n",
                    100 * ((double)cvals[CACHE_MISS] / cvals[CACHE]));

        if (ru)
                showtime(pmc_args.pa_printfile, &before_ts, &after, ru);
}

static struct option longopts[] = {
        {"events", required_argument, NULL, 'j'},
        {NULL, 0, NULL, 0}
};

static int
pmc_stat_internal(int argc, char **argv, int system_mode)
{
        char *event, *r;
        struct sigaction sa;
        struct kevent kev;
        struct rusage ru;
        struct winsize ws;
        struct pmcstat_ev *ev;
        int c, option, runstate;
        int waitstatus, ru_valid, do_debug;

        do_debug = ru_valid = 0;
        r = event = NULL;
        while ((option = getopt_long(argc, argv, "dj:", longopts, NULL)) != -1) {
                switch (option) {
                case 'j':
                        r = event = strdup(optarg);
                        break;
                case 'd':
                        do_debug = 1;
                        break;
                case '?':
                default:
                        usage();
                }
        }
        pmc_args.pa_argc = (argc -= optind);
        pmc_args.pa_argv = (argv += optind);
        if (argc == 0)
                usage();
        pmc_args.pa_flags |= FLAG_HAS_COMMANDLINE;
        pmc_stat_setup_stat(system_mode, event);
        free(r);
        bzero(&ru, sizeof(ru));
        EV_SET(&kev, SIGINT, EVFILT_SIGNAL, EV_ADD, 0, 0, NULL);
        if (kevent(pmc_kq, &kev, 1, NULL, 0, NULL) < 0)
                err(EX_OSERR, "ERROR: Cannot register kevent for SIGINT");

        EV_SET(&kev, SIGIO, EVFILT_SIGNAL, EV_ADD, 0, 0, NULL);
        if (kevent(pmc_kq, &kev, 1, NULL, 0, NULL) < 0)
                err(EX_OSERR, "ERROR: Cannot register kevent for SIGIO");
        EV_SET(&kev, 0, EVFILT_TIMER, EV_ADD, 0, 1000, NULL);
        if (kevent(pmc_kq, &kev, 1, NULL, 0, NULL) < 0)
                err(EX_OSERR,
                        "ERROR: Cannot register kevent for timer");

        STAILQ_FOREACH(ev, &pmc_args.pa_events, ev_next) {
                if (pmc_allocate(ev->ev_spec, ev->ev_mode,
                    ev->ev_flags, ev->ev_cpu, &ev->ev_pmcid, ev->ev_count) < 0)
                        err(EX_OSERR,
                            "ERROR: Cannot allocate %s-mode pmc with specification \"%s\"",
                            PMC_IS_SYSTEM_MODE(ev->ev_mode) ?
                            "system" : "process", ev->ev_spec);

                if (PMC_IS_SAMPLING_MODE(ev->ev_mode) &&
                    pmc_set(ev->ev_pmcid, ev->ev_count) < 0)
                        err(EX_OSERR,
                            "ERROR: Cannot set sampling count for PMC \"%s\"",
                            ev->ev_name);
        }

        /*
         * An exec() failure of a forked child is signalled by the
         * child sending the parent a SIGCHLD.  We don't register an
         * actual signal handler for SIGCHLD, but instead use our
         * kqueue to pick up the signal.
         */
        EV_SET(&kev, SIGCHLD, EVFILT_SIGNAL, EV_ADD, 0, 0, NULL);
        if (kevent(pmc_kq, &kev, 1, NULL, 0, NULL) < 0)
                err(EX_OSERR, "ERROR: Cannot register kevent for SIGCHLD");

        pmcstat_create_process(pmcstat_sockpair, &pmc_args, pmc_kq);

        if (SLIST_EMPTY(&pmc_args.pa_targets))
                errx(EX_DATAERR,
                    "ERROR: No matching target processes.");
        if (pmc_args.pa_flags & FLAG_HAS_PROCESS_PMCS)
                pmcstat_attach_pmcs(&pmc_args);

        /* start the pmcs */
        pmc_util_start_pmcs(&pmc_args);

        /* start the (commandline) process if needed */
        pmcstat_start_process(pmcstat_sockpair);

        /* Handle SIGINT using the kqueue loop */
        sa.sa_handler = SIG_IGN;
        sa.sa_flags = 0;
        (void)sigemptyset(&sa.sa_mask);

        if (sigaction(SIGINT, &sa, NULL) < 0)
                err(EX_OSERR, "ERROR: Cannot install signal handler");

        /*
 * loop till either the target process (if any) exits, or we
 * are killed by a SIGINT or we reached the time duration.
 */
        runstate = PMCSTAT_RUNNING;
        do {
                if ((c = kevent(pmc_kq, NULL, 0, &kev, 1, NULL)) <= 0) {
                        if (errno != EINTR)
                                err(EX_OSERR, "ERROR: kevent failed");
                        else
                                continue;
                }
                if (kev.flags & EV_ERROR)
                        errc(EX_OSERR, kev.data, "ERROR: kevent failed");

                switch (kev.filter) {
                case EVFILT_PROC:       /* target has exited */
                        if (wait4(pmc_util_get_pid(&pmc_args), &waitstatus, 0, &ru) > 0) {
                                getrusage(RUSAGE_CHILDREN, &ru);
                                ru_valid = 1;
                        }
                        break;

                case EVFILT_READ:       /* log file data is present */
                        break;
                case EVFILT_TIMER:
                        if (do_debug)
                                pmc_stat_print_stat(NULL);
                        break;
                case EVFILT_SIGNAL:
                        if (kev.ident == SIGCHLD) {
                                /*
                                 * The child process sends us a
                                 * SIGCHLD if its exec() failed.  We
                                 * wait for it to exit and then exit
                                 * ourselves.
                                 */
                                (void)wait(&c);
                                runstate = PMCSTAT_FINISHED;
                        } else if (kev.ident == SIGIO) {
                                /*
                                 * We get a SIGIO if a PMC loses all
                                 * of its targets, or if logfile
                                 * writes encounter an error.
                                 */
                                if (wait4(pmc_util_get_pid(&pmc_args), &waitstatus, 0, &ru) > 0) {
                                        getrusage(RUSAGE_CHILDREN, &ru);
                                        ru_valid = 1;
                                }
                                runstate = pmcstat_close_log(&pmc_args);
                        } else if (kev.ident == SIGINT) {
                                /* Kill the child process if we started it */
                                if (pmc_args.pa_flags & FLAG_HAS_COMMANDLINE)
                                        pmc_util_kill_process(&pmc_args);
                                runstate = pmcstat_close_log(&pmc_args);
                        } else if (kev.ident == SIGWINCH) {
                                if (ioctl(fileno(pmc_args.pa_printfile),
                                    TIOCGWINSZ, &ws) < 0)
                                        err(EX_OSERR,
                                            "ERROR: Cannot determine window size");
                                pmc_displayheight = ws.ws_row - 1;
                                pmc_displaywidth = ws.ws_col - 1;
                        } else
                                assert(0);

                        break;
                }
        } while (runstate != PMCSTAT_FINISHED);
        if (!ru_valid)
                warnx("couldn't get rusage");
        pmc_stat_print_stat(&ru);
        pmc_util_cleanup(&pmc_args);
        return (0);
}

int
cmd_pmc_stat(int argc, char **argv)
{
        return (pmc_stat_internal(argc, argv, 0));
}

int
cmd_pmc_stat_system(int argc, char **argv)
{
        return (pmc_stat_internal(argc, argv, 1));
}