#include <sys/types.h>
#define _KERNEL_STRUCTURES
#include <sys/file.h>
#include <sys/kinfo.h>

#include <err.h>
#include <fcntl.h>
#include <kvm.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

static void
usage(const char *cmd)
{
        fprintf(stderr, "%s [-N kern] [-M core]\n", cmd);
        exit(1);
}

static const char *
typestr(short type)
{
        static char buf[32];

        switch (type) {
        case DTYPE_VNODE:
                return "file";
        case DTYPE_SOCKET:
                return "socket";
        case DTYPE_PIPE:
                return "pipe";
        case DTYPE_FIFO:
                return "fifo";
        case DTYPE_KQUEUE:
                return "kqueue";
        case DTYPE_CRYPTO:
                return "crypto";
        case DTYPE_MQUEUE:
                return "mqueue";
        default:
                snprintf(buf, sizeof(buf), "?%d", type);
                return buf;
        }
}

int
main(int argc, char *argv[])
{
        const char *file, *core;
        char *errbuf;
        kvm_t *kd;
        int opt, kfile_cnt, i;
        struct kinfo_file *kfile;

        file = NULL;
        core = NULL;

        while ((opt = getopt(argc, argv, "M:N:")) != -1) {
                switch (opt) {
                case 'M':
                        core = optarg;
                        break;

                case 'N':
                        file = optarg;
                        break;

                default:
                        usage(argv[0]);
                }
        }

        errbuf = malloc(_POSIX2_LINE_MAX);
        if (errbuf == NULL)
                err(2, "malloc %d failed", _POSIX2_LINE_MAX);

        kd = kvm_openfiles(file, core, NULL, O_RDONLY, errbuf);
        if (kd == NULL)
                errx(2, "%s", errbuf);

        kfile = kvm_getfiles(kd, 0, 0, &kfile_cnt);
        if (kfile == NULL)
                errx(2, "kvm_getfiles failed %s", kvm_geterr(kd));

        for (i = 0; i < kfile_cnt; ++i) {
                printf("pid %d, fd %d, type %s\n",
                    kfile[i].f_pid, kfile[i].f_fd, typestr(kfile[i].f_type));
        }

        kvm_close(kd);

        return 0;
}