#define _GNU_SOURCE

#include <assert.h>
#include <fcntl.h>
#include <linux/perf_event.h>
#include <linux/bpf.h>
#include <sched.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <sys/resource.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>

#include "bpf_load.h"
#include "libbpf.h"
#include "perf-sys.h"

#define SAMPLE_PERIOD  0x7fffffffffffffffULL

static void check_on_cpu(int cpu, struct perf_event_attr *attr)
{
        int pmu_fd, error = 0;
        cpu_set_t set;
        __u64 value;

        /* Move to target CPU */
        CPU_ZERO(&set);
        CPU_SET(cpu, &set);
        assert(sched_setaffinity(0, sizeof(set), &set) == 0);
        /* Open perf event and attach to the perf_event_array */
        pmu_fd = sys_perf_event_open(attr, -1/*pid*/, cpu/*cpu*/, -1/*group_fd*/, 0);
        if (pmu_fd < 0) {
                fprintf(stderr, "sys_perf_event_open failed on CPU %d\n", cpu);
                error = 1;
                goto on_exit;
        }
        assert(bpf_map_update_elem(map_fd[0], &cpu, &pmu_fd, BPF_ANY) == 0);
        assert(ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0) == 0);
        /* Trigger the kprobe */
        bpf_map_get_next_key(map_fd[1], &cpu, NULL);
        /* Check the value */
        if (bpf_map_lookup_elem(map_fd[1], &cpu, &value)) {
                fprintf(stderr, "Value missing for CPU %d\n", cpu);
                error = 1;
                goto on_exit;
        }
        fprintf(stderr, "CPU %d: %llu\n", cpu, value);

on_exit:
        assert(bpf_map_delete_elem(map_fd[0], &cpu) == 0 || error);
        assert(ioctl(pmu_fd, PERF_EVENT_IOC_DISABLE, 0) == 0 || error);
        assert(close(pmu_fd) == 0 || error);
        assert(bpf_map_delete_elem(map_fd[1], &cpu) == 0 || error);
        exit(error);
}

static void test_perf_event_array(struct perf_event_attr *attr,
                                  const char *name)
{
        int i, status, nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
        pid_t pid[nr_cpus];
        int err = 0;

        printf("Test reading %s counters\n", name);

        for (i = 0; i < nr_cpus; i++) {
                pid[i] = fork();
                assert(pid[i] >= 0);
                if (pid[i] == 0) {
                        check_on_cpu(i, attr);
                        exit(1);
                }
        }

        for (i = 0; i < nr_cpus; i++) {
                assert(waitpid(pid[i], &status, 0) == pid[i]);
                err |= status;
        }

        if (err)
                printf("Test: %s FAILED\n", name);
}

static void test_bpf_perf_event(void)
{
        struct perf_event_attr attr_cycles = {
                .freq = 0,
                .sample_period = SAMPLE_PERIOD,
                .inherit = 0,
                .type = PERF_TYPE_HARDWARE,
                .read_format = 0,
                .sample_type = 0,
                .config = PERF_COUNT_HW_CPU_CYCLES,
        };
        struct perf_event_attr attr_clock = {
                .freq = 0,
                .sample_period = SAMPLE_PERIOD,
                .inherit = 0,
                .type = PERF_TYPE_SOFTWARE,
                .read_format = 0,
                .sample_type = 0,
                .config = PERF_COUNT_SW_CPU_CLOCK,
        };
        struct perf_event_attr attr_raw = {
                .freq = 0,
                .sample_period = SAMPLE_PERIOD,
                .inherit = 0,
                .type = PERF_TYPE_RAW,
                .read_format = 0,
                .sample_type = 0,
                /* Intel Instruction Retired */
                .config = 0xc0,
        };
        struct perf_event_attr attr_l1d_load = {
                .freq = 0,
                .sample_period = SAMPLE_PERIOD,
                .inherit = 0,
                .type = PERF_TYPE_HW_CACHE,
                .read_format = 0,
                .sample_type = 0,
                .config =
                        PERF_COUNT_HW_CACHE_L1D |
                        (PERF_COUNT_HW_CACHE_OP_READ << 8) |
                        (PERF_COUNT_HW_CACHE_RESULT_ACCESS << 16),
        };
        struct perf_event_attr attr_llc_miss = {
                .freq = 0,
                .sample_period = SAMPLE_PERIOD,
                .inherit = 0,
                .type = PERF_TYPE_HW_CACHE,
                .read_format = 0,
                .sample_type = 0,
                .config =
                        PERF_COUNT_HW_CACHE_LL |
                        (PERF_COUNT_HW_CACHE_OP_READ << 8) |
                        (PERF_COUNT_HW_CACHE_RESULT_MISS << 16),
        };
        struct perf_event_attr attr_msr_tsc = {
                .freq = 0,
                .sample_period = 0,
                .inherit = 0,
                /* From /sys/bus/event_source/devices/msr/ */
                .type = 7,
                .read_format = 0,
                .sample_type = 0,
                .config = 0,
        };

        test_perf_event_array(&attr_cycles, "HARDWARE-cycles");
        test_perf_event_array(&attr_clock, "SOFTWARE-clock");
        test_perf_event_array(&attr_raw, "RAW-instruction-retired");
        test_perf_event_array(&attr_l1d_load, "HW_CACHE-L1D-load");

        /* below tests may fail in qemu */
        test_perf_event_array(&attr_llc_miss, "HW_CACHE-LLC-miss");
        test_perf_event_array(&attr_msr_tsc, "Dynamic-msr-tsc");
}

int main(int argc, char **argv)
{
        struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
        char filename[256];

        snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);

        setrlimit(RLIMIT_MEMLOCK, &r);
        if (load_bpf_file(filename)) {
                printf("%s", bpf_log_buf);
                return 1;
        }

        test_bpf_perf_event();
        return 0;
}