// SPDX-License-Identifier: GPL-2.0
#include <stdlib.h>
#include <stddef.h>
#include <ftw.h>
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>
#include <pthread.h>
#include <sys/mman.h>
#include <sys/wait.h>
#include <linux/kernel.h>
#include <linux/time64.h>
#include <linux/list.h>
#include <linux/err.h>
#include <linux/zalloc.h>
#include <internal/lib.h>
#include <subcmd/parse-options.h>

#include "bench.h"
#include "util/data.h"
#include "util/stat.h"
#include "util/debug.h"
#include "util/symbol.h"
#include "util/session.h"
#include "util/build-id.h"
#include "util/sample.h"
#include "util/synthetic-events.h"

#define MMAP_DEV_MAJOR  8
#define DSO_MMAP_RATIO  4

static unsigned int iterations = 100;
static unsigned int nr_mmaps   = 100;
static unsigned int nr_samples = 100;  /* samples per mmap */

static u64 bench_sample_type;
static u16 bench_id_hdr_size;

struct bench_data {
        int                     pid;
        int                     input_pipe[2];
        int                     output_pipe[2];
        pthread_t               th;
};

struct bench_dso {
        struct list_head        list;
        char                    *name;
        int                     ino;
};

static int nr_dsos;
static struct bench_dso *dsos;

extern int main(int argc, const char **argv);

static const struct option options[] = {
        OPT_UINTEGER('i', "iterations", &iterations,
                     "Number of iterations used to compute average (default: 100)"),
        OPT_UINTEGER('m', "nr-mmaps", &nr_mmaps,
                     "Number of mmap events for each iteration (default: 100)"),
        OPT_UINTEGER('n', "nr-samples", &nr_samples,
                     "Number of sample events per mmap event (default: 100)"),
        OPT_INCR('v', "verbose", &verbose,
                 "be more verbose (show iteration count, DSO name, etc)"),
        OPT_END()
};

static const char *const bench_usage[] = {
        "perf bench internals inject-build-id <options>",
        NULL
};

/*
 * Helper for collect_dso that adds the given file as a dso to dso_list
 * if it contains a build-id.  Stops after collecting 4 times more than
 * we need (for MMAP2 events).
 */
static int add_dso(const char *fpath, const struct stat *sb __maybe_unused,
                   int typeflag, struct FTW *ftwbuf __maybe_unused)
{
        struct bench_dso *dso = &dsos[nr_dsos];
        struct build_id bid = { .size = 0, };

        if (typeflag == FTW_D || typeflag == FTW_SL)
                return 0;

        if (filename__read_build_id(fpath, &bid) < 0)
                return 0;

        dso->name = realpath(fpath, NULL);
        if (dso->name == NULL)
                return -1;

        dso->ino = nr_dsos++;
        pr_debug2("  Adding DSO: %s\n", fpath);

        /* stop if we collected enough DSOs */
        if ((unsigned int)nr_dsos == DSO_MMAP_RATIO * nr_mmaps)
                return 1;

        return 0;
}

static void collect_dso(void)
{
        dsos = calloc(nr_mmaps * DSO_MMAP_RATIO, sizeof(*dsos));
        if (dsos == NULL) {
                printf("  Memory allocation failed\n");
                exit(1);
        }

        if (nftw("/usr/lib/", add_dso, 10, FTW_PHYS) < 0)
                return;

        pr_debug("  Collected %d DSOs\n", nr_dsos);
}

static void release_dso(void)
{
        int i;

        for (i = 0; i < nr_dsos; i++) {
                struct bench_dso *dso = &dsos[i];

                zfree(&dso->name);
        }
        free(dsos);
}

/* Fake address used by mmap and sample events */
static u64 dso_map_addr(struct bench_dso *dso)
{
        return 0x400000ULL + dso->ino * 8192ULL;
}

static ssize_t synthesize_attr(struct bench_data *data)
{
        union perf_event event;

        memset(&event, 0, sizeof(event.attr) + sizeof(u64));

        event.header.type = PERF_RECORD_HEADER_ATTR;
        event.header.size = sizeof(event.attr) + sizeof(u64);

        event.attr.attr.type = PERF_TYPE_SOFTWARE;
        event.attr.attr.config = PERF_COUNT_SW_TASK_CLOCK;
        event.attr.attr.exclude_kernel = 1;
        event.attr.attr.sample_id_all = 1;
        event.attr.attr.sample_type = bench_sample_type;

        return writen(data->input_pipe[1], &event, event.header.size);
}

static ssize_t synthesize_fork(struct bench_data *data)
{
        union perf_event event;

        memset(&event, 0, sizeof(event.fork) + bench_id_hdr_size);

        event.header.type = PERF_RECORD_FORK;
        event.header.misc = PERF_RECORD_MISC_FORK_EXEC;
        event.header.size = sizeof(event.fork) + bench_id_hdr_size;

        event.fork.ppid = 1;
        event.fork.ptid = 1;
        event.fork.pid = data->pid;
        event.fork.tid = data->pid;

        return writen(data->input_pipe[1], &event, event.header.size);
}

static ssize_t synthesize_mmap(struct bench_data *data, struct bench_dso *dso, u64 timestamp)
{
        union perf_event event;
        size_t len = offsetof(struct perf_record_mmap2, filename);
        u64 *id_hdr_ptr = (void *)&event;
        int ts_idx;

        len += roundup(strlen(dso->name) + 1, 8) + bench_id_hdr_size;

        memset(&event, 0, min(len, sizeof(event.mmap2)));

        event.header.type = PERF_RECORD_MMAP2;
        event.header.misc = PERF_RECORD_MISC_USER;
        event.header.size = len;

        event.mmap2.pid = data->pid;
        event.mmap2.tid = data->pid;
        event.mmap2.maj = MMAP_DEV_MAJOR;
        event.mmap2.ino = dso->ino;

        strcpy(event.mmap2.filename, dso->name);

        event.mmap2.start = dso_map_addr(dso);
        event.mmap2.len = 4096;
        event.mmap2.prot = PROT_EXEC;

        if (len > sizeof(event.mmap2)) {
                /* write mmap2 event first */
                if (writen(data->input_pipe[1], &event, len - bench_id_hdr_size) < 0)
                        return -1;
                /* zero-fill sample id header */
                memset(id_hdr_ptr, 0, bench_id_hdr_size);
                /* put timestamp in the right position */
                ts_idx = (bench_id_hdr_size / sizeof(u64)) - 2;
                id_hdr_ptr[ts_idx] = timestamp;
                if (writen(data->input_pipe[1], id_hdr_ptr, bench_id_hdr_size) < 0)
                        return -1;

                return len;
        }

        ts_idx = (len / sizeof(u64)) - 2;
        id_hdr_ptr[ts_idx] = timestamp;
        return writen(data->input_pipe[1], &event, len);
}

static ssize_t synthesize_sample(struct bench_data *data, struct bench_dso *dso, u64 timestamp)
{
        union perf_event event;
        struct perf_sample sample = {
                .tid = data->pid,
                .pid = data->pid,
                .ip = dso_map_addr(dso),
                .time = timestamp,
        };

        event.header.type = PERF_RECORD_SAMPLE;
        event.header.misc = PERF_RECORD_MISC_USER;
        event.header.size = perf_event__sample_event_size(&sample, bench_sample_type, 0);

        perf_event__synthesize_sample(&event, bench_sample_type, 0, &sample);

        return writen(data->input_pipe[1], &event, event.header.size);
}

static ssize_t synthesize_flush(struct bench_data *data)
{
        struct perf_event_header header = {
                .size = sizeof(header),
                .type = PERF_RECORD_FINISHED_ROUND,
        };

        return writen(data->input_pipe[1], &header, header.size);
}

static void *data_reader(void *arg)
{
        struct bench_data *data = arg;
        char buf[8192];
        int flag;
        int n;

        flag = fcntl(data->output_pipe[0], F_GETFL);
        fcntl(data->output_pipe[0], F_SETFL, flag | O_NONBLOCK);

        /* read out data from child */
        while (true) {
                n = read(data->output_pipe[0], buf, sizeof(buf));
                if (n > 0)
                        continue;
                if (n == 0)
                        break;

                if (errno != EINTR && errno != EAGAIN)
                        break;

                usleep(100);
        }

        close(data->output_pipe[0]);
        return NULL;
}

static int setup_injection(struct bench_data *data, bool build_id_all)
{
        int ready_pipe[2];
        int dev_null_fd;
        char buf;

        if (pipe(ready_pipe) < 0)
                return -1;

        if (pipe(data->input_pipe) < 0)
                return -1;

        if (pipe(data->output_pipe) < 0)
                return -1;

        data->pid = fork();
        if (data->pid < 0)
                return -1;

        if (data->pid == 0) {
                const char **inject_argv;
                int inject_argc = 3;

                close(data->input_pipe[1]);
                close(data->output_pipe[0]);
                close(ready_pipe[0]);

                dup2(data->input_pipe[0], STDIN_FILENO);
                close(data->input_pipe[0]);
                dup2(data->output_pipe[1], STDOUT_FILENO);
                close(data->output_pipe[1]);

                dev_null_fd = open("/dev/null", O_WRONLY);
                if (dev_null_fd < 0)
                        exit(1);

                dup2(dev_null_fd, STDERR_FILENO);

                if (build_id_all)
                        inject_argc++;

                inject_argv = calloc(inject_argc + 1, sizeof(*inject_argv));
                if (inject_argv == NULL)
                        exit(1);

                inject_argv[0] = strdup("perf");
                inject_argv[1] = strdup("inject");
                inject_argv[2] = strdup("-b");
                if (build_id_all)
                        inject_argv[3] = strdup("--buildid-all");

                /* signal that we're ready to go */
                close(ready_pipe[1]);

                main(inject_argc, inject_argv);

                exit(0);
        }

        pthread_create(&data->th, NULL, data_reader, data);

        close(ready_pipe[1]);
        close(data->input_pipe[0]);
        close(data->output_pipe[1]);

        /* wait for child ready */
        if (read(ready_pipe[0], &buf, 1) < 0)
                return -1;
        close(ready_pipe[0]);

        return 0;
}

static int inject_build_id(struct bench_data *data, u64 *max_rss)
{
        int status;
        unsigned int i, k;
        struct rusage rusage;

        /* this makes the child to run */
        if (perf_header__write_pipe(data->input_pipe[1]) < 0)
                return -1;

        if (synthesize_attr(data) < 0)
                return -1;

        if (synthesize_fork(data) < 0)
                return -1;

        for (i = 0; i < nr_mmaps; i++) {
                int idx = rand() % nr_dsos;
                struct bench_dso *dso = &dsos[idx];
                u64 timestamp = rand() % 1000000;

                pr_debug2("   [%d] injecting: %s\n", i+1, dso->name);
                if (synthesize_mmap(data, dso, timestamp) < 0)
                        return -1;

                for (k = 0; k < nr_samples; k++) {
                        if (synthesize_sample(data, dso, timestamp + k * 1000) < 0)
                                return -1;
                }

                if ((i + 1) % 10 == 0) {
                        if (synthesize_flush(data) < 0)
                                return -1;
                }
        }

        /* this makes the child to finish */
        close(data->input_pipe[1]);

        wait4(data->pid, &status, 0, &rusage);
        *max_rss = rusage.ru_maxrss;

        pr_debug("   Child %d exited with %d\n", data->pid, status);

        return 0;
}

static void do_inject_loop(struct bench_data *data, bool build_id_all)
{
        unsigned int i;
        struct stats time_stats, mem_stats;
        double time_average, time_stddev;
        double mem_average, mem_stddev;

        init_stats(&time_stats);
        init_stats(&mem_stats);

        pr_debug("  Build-id%s injection benchmark\n", build_id_all ? "-all" : "");

        for (i = 0; i < iterations; i++) {
                struct timeval start, end, diff;
                u64 runtime_us, max_rss;

                pr_debug("  Iteration #%d\n", i+1);

                if (setup_injection(data, build_id_all) < 0) {
                        printf("  Build-id injection setup failed\n");
                        break;
                }

                gettimeofday(&start, NULL);
                if (inject_build_id(data, &max_rss) < 0) {
                        printf("  Build-id injection failed\n");
                        break;
                }

                gettimeofday(&end, NULL);
                timersub(&end, &start, &diff);
                runtime_us = diff.tv_sec * USEC_PER_SEC + diff.tv_usec;
                update_stats(&time_stats, runtime_us);
                update_stats(&mem_stats, max_rss);

                pthread_join(data->th, NULL);
        }

        time_average = avg_stats(&time_stats) / USEC_PER_MSEC;
        time_stddev = stddev_stats(&time_stats) / USEC_PER_MSEC;
        printf("  Average build-id%s injection took: %.3f msec (+- %.3f msec)\n",
               build_id_all ? "-all" : "", time_average, time_stddev);

        /* each iteration, it processes MMAP2 + BUILD_ID + nr_samples * SAMPLE */
        time_average = avg_stats(&time_stats) / (nr_mmaps * (nr_samples + 2));
        time_stddev = stddev_stats(&time_stats) / (nr_mmaps * (nr_samples + 2));
        printf("  Average time per event: %.3f usec (+- %.3f usec)\n",
                time_average, time_stddev);

        mem_average = avg_stats(&mem_stats);
        mem_stddev = stddev_stats(&mem_stats);
        printf("  Average memory usage: %.0f KB (+- %.0f KB)\n",
                mem_average, mem_stddev);
}

static int do_inject_loops(struct bench_data *data)
{

        srand(time(NULL));
        symbol__init(NULL);

        bench_sample_type  = PERF_SAMPLE_IDENTIFIER | PERF_SAMPLE_IP;
        bench_sample_type |= PERF_SAMPLE_TID | PERF_SAMPLE_TIME;
        bench_id_hdr_size  = 32;

        collect_dso();
        if (nr_dsos == 0) {
                printf("  Cannot collect DSOs for injection\n");
                return -1;
        }

        do_inject_loop(data, false);
        do_inject_loop(data, true);

        release_dso();
        return 0;
}

int bench_inject_build_id(int argc, const char **argv)
{
        struct bench_data data;

        argc = parse_options(argc, argv, options, bench_usage, 0);
        if (argc) {
                usage_with_options(bench_usage, options);
                exit(EXIT_FAILURE);
        }

        return do_inject_loops(&data);
}