/*
 * Copyright (c) 2019, Nutanix Inc. All rights reserved.
 *     Author: Thanos Makatos <thanos@nutanix.com>
 *             Swapnil Ingle <swapnil.ingle@nutanix.com>
 *             Felipe Franciosi <felipe@nutanix.com>
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions are met:
 *      * Redistributions of source code must retain the above copyright
 *        notice, this list of conditions and the following disclaimer.
 *      * 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.
 *      * Neither the name of Nutanix 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 COPYRIGHT HOLDERS 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 <COPYRIGHT HOLDER> 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.
 *
 */

/*
 * gpio-pci-idio-16: a simple example server identifying as a GPIO PCI device.
 */

#include <stdio.h>
#include <err.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <signal.h>
#include <errno.h>

#include "common.h"
#include "libvfio-user.h"
#include "tran_sock.h"

static void
_log(UNUSED void *pvt, UNUSED vfu_log_lvl_t lvl, char const *msg)
{
    fprintf(stderr, "gpio: %s\n", msg);
}

ssize_t
bar2_access(UNUSED void *pvt, char * const buf, size_t count, loff_t offset,
            const bool is_write)
{
    static char n;

    if (offset == 0 && !is_write)
        buf[0] = n++ / 3;

    return count;
}

static void _sa_handler(UNUSED int signum)
{
}

int
main(int argc, char *argv[])
{
    int ret;
    bool verbose = false;
    char opt;
    struct sigaction act = { .sa_handler = _sa_handler };
    vfu_ctx_t *vfu_ctx;
    vfu_pci_hdr_id_t id = { .vid = 0x494F, .did = 0x0DC8 };
    vfu_pci_hdr_ss_t ss = { .vid = 0x0, .sid = 0x0 };
    vfu_pci_hdr_cc_t cc = { { 0 } };

    while ((opt = getopt(argc, argv, "v")) != -1) {
        switch (opt) {
            case 'v':
                verbose = true;
                break;
            default: /* '?' */
                fprintf(stderr, "Usage: %s [-v] <socketpath>\n", argv[0]);
                exit(EXIT_FAILURE);
        }
    }

    if (optind >= argc) {
        errx(EXIT_FAILURE, "missing vfio-user socket path");
    }

    sigemptyset(&act.sa_mask);
    if (sigaction(SIGINT, &act, NULL) == -1) {
        err(EXIT_FAILURE, "failed to register signal handler");
    }

    vfu_ctx = vfu_create_ctx(VFU_TRANS_SOCK, argv[optind], 0, NULL,
                             VFU_DEV_TYPE_PCI);
    if (vfu_ctx == NULL) {
        if (errno == EINTR) {
            printf("interrupted\n");
            exit(EXIT_SUCCESS);
        }
        err(EXIT_FAILURE, "failed to initialize device emulation");
    }

    ret = vfu_setup_log(vfu_ctx, _log, verbose ? VFU_DBG : VFU_ERR);
    if (ret < 0) {
        err(EXIT_FAILURE, "failed to setup log");
    }

    ret = vfu_pci_setup_config_hdr(vfu_ctx, id, ss, cc, false);
    if (ret < 0) {
        fprintf(stderr, "failed to setup pci header\n");
        goto out;
    }

    ret = vfu_setup_region(vfu_ctx, VFU_PCI_DEV_BAR2_REGION_IDX, 0x100,
                           &bar2_access, VFU_REG_FLAG_RW, NULL, 0, NULL);
    if (ret < 0) {
        fprintf(stderr, "failed to setup region\n");
        goto out;
    }

    ret = vfu_ctx_drive(vfu_ctx);
    if (ret != 0) {
        if (ret != -ENOTCONN && ret != -EINTR) {
            fprintf(stderr, "failed to realize device emulation\n");
            goto out;
        }
        ret = 0;
    }

out:
    vfu_destroy_ctx(vfu_ctx);
    return ret;
}

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