/*
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 2002 Adrian Chadd <adrian@FreeBSD.org>.
 * All rights reserved.
 *
 * This software was developed for the FreeBSD Project by Marshall
 * Kirk McKusick and Network Associates Laboratories, the Security
 * Research Division of Network Associates, Inc. under DARPA/SPAWAR
 * contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS
 * research program.
 *
 * Copyright (c) 1980, 1989, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * 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.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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/types.h>
#include <sys/disk.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <aio.h>
#include <assert.h>
#include <ctype.h>
#include <err.h>
#include <fcntl.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

/*
 * This is a bit of a quick hack to do parallel IO testing through POSIX AIO.
 * Its specifically designed to work under FreeBSD and its derivatives;
 * note how I cheat by using aio_waitcomplete().
 *
 * TODO:
 *
 * + Add write support; so we can make sure we're not hitting throughput issues
 *   with read/modify/write of entire tracks of the disk
 * + Add in per-op stats - time and offset - so one could start mapping out
 *   the speed hotspots of the disk
 * + Add in different distributions - random, normal, left/right skewed normal,
 *   zipf, etc - and perhaps add the ability to run concurrent distributions
 *   (so a normal and a zipf; and also a random read; zipf write, etc.)
 *
 * Adrian Chadd <adrian@creative.net.au>
 */

typedef enum {
        IOT_NONE = 0x00,
        IOT_READ = 0x01,
        IOT_WRITE = 0x02
} iot_t;

static size_t
disk_getsize(int fd)
{
        off_t mediasize;        

        if (ioctl(fd, DIOCGMEDIASIZE, &mediasize) < 0)
                err(1, "ioctl(DIOCGMEDIASIZE)");
        return (mediasize);
}

static iot_t
choose_aio(iot_t iomask)
{
        /* choose a random read or write event, limited by the mask */
        if (iomask == IOT_READ)
                return IOT_READ;
        else if (iomask == IOT_WRITE)
                return IOT_WRITE;
        return (random() & 0x01 ? IOT_READ : IOT_WRITE);
}

static void
set_aio(struct aiocb *a, iot_t iot, int fd, off_t offset, int size, char *buf)
{
        int r;
        bzero(a, sizeof(*a));
        a->aio_fildes = fd;
        a->aio_nbytes = size;
        a->aio_offset = offset;
        a->aio_buf = buf;
        if (iot == IOT_READ)
                r = aio_read(a);
        else
                r = aio_write(a);
        if (r != 0)
                err(1, "set_aio call failed");
}

int
main(int argc, char *argv[])
{
        int fd;
        struct stat sb;
        struct aiocb *aio;
        char **abuf;
        const char *fn;
        int aio_len;
        int io_size, nrun;
        off_t file_size, offset;
        struct aiocb *a;
        int i, n;
        struct timeval st, et, rt;
        float f_rt;
        iot_t iowhat;


        if (argc < 6) {
                printf("Usage: %s <file> <io size> <number of runs> <concurrency> <ro|wo|rw>\n",
                    argv[0]);
                exit(1);
        }

        fn = argv[1];
        io_size = atoi(argv[2]);
        if (io_size <= 0)
                errx(1, "the I/O size must be >0");
        nrun = atoi(argv[3]);
        if (nrun <= 0)
                errx(1, "the number of runs must be >0");
        aio_len = atoi(argv[4]);
        if (aio_len <= 0)
                errx(1, "AIO concurrency must be >0");
        if (strcmp(argv[5], "ro") == 0)
                iowhat = IOT_READ;
        else if (strcmp(argv[5], "rw") == 0)
                iowhat = IOT_READ | IOT_WRITE;
        else if (strcmp(argv[5], "wo") == 0)
                iowhat = IOT_WRITE;
        else
                errx(1, "the I/O type needs to be \"ro\", \"rw\", or \"wo\"!\n");

        /*
         * Random returns values between 0 and (2^32)-1; only good for 4 gig.
         * Lets instead treat random() as returning a block offset w/ block size
         * being "io_size", so we can handle > 4 gig files.
         */
        if (iowhat == IOT_READ)
                fd = open(fn, O_RDONLY | O_DIRECT);
        else if (iowhat == IOT_WRITE)
                fd = open(fn, O_WRONLY | O_DIRECT);
        else
                fd = open(fn, O_RDWR | O_DIRECT);

        if (fd < 0)
                err(1, "open failed");
        if (fstat(fd, &sb) < 0)
                err(1, "fstat failed");
        if (S_ISREG(sb.st_mode)) {
                file_size = sb.st_size;
        } else if (S_ISBLK(sb.st_mode) || S_ISCHR(sb.st_mode)) {
                file_size = disk_getsize(fd);
        } else
                errx(1, "unknown file type");
        if (file_size <= 0)
                errx(1, "path provided too small");

        printf("File: %s; File size %jd bytes\n", fn, (intmax_t)file_size);

        aio = calloc(aio_len, sizeof(struct aiocb));
        abuf = calloc(aio_len, sizeof(char *));
        for (i = 0; i < aio_len; i++)
                abuf[i] = calloc(1, io_size * sizeof(char));

        /* Fill with the initial contents */
        gettimeofday(&st, NULL);
        for (i = 0; i < aio_len; i++) {
                offset = random() % (file_size / io_size);
                offset *= io_size;
                set_aio(aio + i, choose_aio(iowhat), fd, offset, io_size, abuf[i]);
        }

        for (i = 0; i < nrun; i++) {
                aio_waitcomplete(&a, NULL);
                n = a - aio;
                assert(n < aio_len);
                assert(n >= 0);
                offset = random() % (file_size / io_size);
                offset *= io_size;
                set_aio(aio + n, choose_aio(iowhat), fd, offset, io_size, abuf[n]);
        }

        gettimeofday(&et, NULL);
        timersub(&et, &st, &rt);
        f_rt = ((float) (rt.tv_usec)) / 1000000.0;
        f_rt += (float) (rt.tv_sec);
        printf("Runtime: %.2f seconds, ", f_rt);
        printf("Op rate: %.2f ops/sec, ", ((float) (nrun))  / f_rt);
        printf("Avg transfer rate: %.2f bytes/sec\n", ((float) (nrun)) * ((float)io_size) / f_rt);



        exit(0);
}