static void
usage()
{
    pr2serr("Usage: sg_referrals  [--help] [--hex] [--lba=LBA] "
            "[--maxlen=LEN]\n"
            "                     [--one-segment] [--raw] [--readonly] "
            "[--verbose]\n"
            "                     [--version] DEVICE\n"
            "  where:\n"
            "    --help|-h         print out usage message\n"
            "    --hex|-H          output in hexadecimal\n"
            "    --lba=LBA|-l LBA    starting LBA (logical block address) "
            "(def: 0)\n"
            "    --maxlen=LEN|-m LEN    max response length (allocation "
            "length in cdb)\n"
            "                           (def: 0 -> %d bytes)\n",
            DEF_REFER_BUFF_LEN );
    pr2serr("    --one-segment|-s    return information about the specified "
            "segment only\n"
            "    --raw|-r          output in binary\n"
            "    --verbose|-v      increase verbosity\n"
            "    --version|-V      print version string and exit\n\n"
            "Performs a SCSI REPORT REFERRALS command (SBC-3)\n"
            );
}

static void
write2wfn(FILE * fp, struct opts_t * op)
{
    int k, n;
    size_t s;
    char b[128];

    if (op->do_hex) {
        for (k = 0, n = 0; k < op->sense_len; ++k) {
            n += sprintf(b + n, "0x%02x,", op->sense[k]);
            if (15 == (k % 16)) {
                b[n] = '\n';
                s = fwrite(b, 1, n + 1, fp);
                if ((int)s != (n + 1))
                    pr2serr("only able to write %d of %d bytes to %s\n",
                            (int)s, n + 1, op->wfname);
                n = 0;
            }
        }
        if (n > 0) {
            b[n] = '\n';
            s = fwrite(b, 1, n + 1, fp);
            if ((int)s != (n + 1))
                pr2serr("only able to write %d of %d bytes to %s\n", (int)s,
                        n + 1, op->wfname);
        }
    } else {
        s = fwrite(op->sense, 1, op->sense_len, fp);
        if ((int)s != op->sense_len)
            pr2serr("only able to write %d of %d bytes to %s\n", (int)s,
                    op->sense_len, op->wfname);
    }
}

static void
calc_duration_throughput(int contin)
{
    struct timeval end_tm, res_tm;
    double a, b;

    if (start_tm_valid && (start_tm.tv_sec || start_tm.tv_usec)) {
        gettimeofday(&end_tm, NULL);
        res_tm.tv_sec = end_tm.tv_sec - start_tm.tv_sec;
        res_tm.tv_usec = end_tm.tv_usec - start_tm.tv_usec;
        if (res_tm.tv_usec < 0) {
            --res_tm.tv_sec;
            res_tm.tv_usec += 1000000;
        }
        a = res_tm.tv_sec;
        a += (0.000001 * res_tm.tv_usec);
        b = (double)blk_sz * (req_count - dd_count);
        pr2serr("time to transfer data%s: %d.%06d secs",
                (contin ? " so far" : ""), (int)res_tm.tv_sec,
                (int)res_tm.tv_usec);
        if ((a > 0.00001) && (b > 511))
            pr2serr(" at %.2f MB/sec\n", b / (a * 1000000.0));
        else
            pr2serr("\n");
    }
}

/* Invokes a SCSI READ BUFFER(10) command (spc5r02).  Return of 0 -> success,
 * various SG_LIB_CAT_* positive values or -1 -> other errors */
static int
sg_ll_read_buffer_10(int sg_fd, int rb_mode, int rb_mode_sp, int rb_id,
                     uint32_t rb_offset, void * resp, int mx_resp_len,
                     int * residp, bool noisy, int verbose)
{
    int k, ret, res, sense_cat;
    uint8_t rb10_cb[SG_READ_BUFFER_10_CMDLEN] =
          {SG_READ_BUFFER_10_CMD, 0, 0, 0,  0, 0, 0, 0, 0, 0};
    uint8_t sense_b[SENSE_BUFF_LEN];
    struct sg_pt_base * ptvp;

    rb10_cb[1] = (uint8_t)(rb_mode & 0x1f);
    if (rb_mode_sp)
        rb10_cb[1] |= (uint8_t)((rb_mode_sp & 0x7) << 5);
    rb10_cb[2] = (uint8_t)rb_id;
    sg_put_unaligned_be24(rb_offset, rb10_cb + 3);
    sg_put_unaligned_be24(mx_resp_len, rb10_cb + 6);
    if (verbose) {
        pr2serr("    Read buffer(10) cdb: ");
        for (k = 0; k < SG_READ_BUFFER_10_CMDLEN; ++k)
            pr2serr("%02x ", rb10_cb[k]);
        pr2serr("\n");
    }

    ptvp = construct_scsi_pt_obj();
    if (NULL == ptvp) {
        pr2serr("Read buffer(10): out of memory\n");
        return -1;
    }
    set_scsi_pt_cdb(ptvp, rb10_cb, sizeof(rb10_cb));
    set_scsi_pt_sense(ptvp, sense_b, sizeof(sense_b));
    set_scsi_pt_data_in(ptvp, (uint8_t *)resp, mx_resp_len);
    res = do_scsi_pt(ptvp, sg_fd, DEF_PT_TIMEOUT, verbose);
    ret = sg_cmds_process_resp(ptvp, "Read buffer(10)", res, mx_resp_len,
                               sense_b, noisy, verbose, &sense_cat);
    if (-1 == ret)
        ret = sg_convert_errno(get_scsi_pt_os_err(ptvp));
    else if (-2 == ret) {
        switch (sense_cat) {
        case SG_LIB_CAT_RECOVERED:
        case SG_LIB_CAT_NO_SENSE:
            ret = 0;
            break;
        default:
            ret = sense_cat;
            break;
        }
    } else {
        if ((verbose > 2) && (ret > 0)) {
            pr2serr("    Read buffer(10): response%s\n",
                    (ret > 256 ? ", first 256 bytes" : ""));
            hex2stderr((const uint8_t *)resp, (ret > 256 ? 256 : ret), -1);
        }
        ret = 0;
    }
    if (residp)
        *residp = get_scsi_pt_resid(ptvp);
    destruct_scsi_pt_obj(ptvp);
    return ret;
}

static void
usage()
{
    pr2serr("Usage: "
            "sg_bg_ctl  [--ctl=CTL] [--help] [--time=TN] [--verbose] "
            "[--version]\n"
            "                  DEVICE\n");
    pr2serr("  where:\n"
            "    --ctl=CTL|-c CTL    CTL is background operation control "
            "value\n"
            "                        default: 0 -> don't change background "
            "operations\n"
            "                        1 -> start; 2 -> stop\n"
            "    --help|-h          print out usage message\n"
            "    --time=TN|-t TN    TN (units 100 ms) is max time to perform "
            "background\n"
            "                       operations (def: 0 -> no limit)\n"
            "    --verbose|-v       increase verbosity\n"
            "    --version|-V       print version string and exit\n\n"
            "Performs a SCSI BACKGROUND CONTROL command. It can start or "
            "stop\n'advanced background operations'. Operations started by "
            "this command\n(i.e. when ctl=1) are termed as 'host initiated' "
            "and allow a resource or\nthin provisioned device (disk) to "
            "perform garbage collection type operations.\nThese may "
            "degrade performance while they occur. Hence it is best to\n"
            "perform this action while the computer is not too busy.\n");
}

/* Returns 0 if successful */
static int
process_read_long(int sg_fd, bool do_16, bool pblock, bool correct,
                  uint64_t llba, void * data_out, int xfer_len, int verbose)
{
    int offset, res;
    const char * ten_or;
    char b[80];

    if (do_16)
        res = sg_ll_read_long16(sg_fd, pblock, correct, llba, data_out,
                                xfer_len, &offset, true, verbose);
    else
        res = sg_ll_read_long10(sg_fd, pblock, correct, (unsigned int)llba,
                                data_out, xfer_len, &offset, true, verbose);
    ten_or = do_16 ? "16" : "10";
    switch (res) {
    case 0:
        break;
    case SG_LIB_CAT_ILLEGAL_REQ_WITH_INFO:
        pr2serr("<<< device indicates 'xfer_len' should be %d >>>\n",
                xfer_len - offset);
        break;
    default:
        sg_get_category_sense_str(res, sizeof(b), b, verbose);
        pr2serr("  SCSI READ LONG (%s): %s\n", ten_or, b);
        break;
    }
    return res;
}

static void
print_stats()
{
    if (0 != dd_count)
        pr2serr("  remaining block count=%" PRId64 "\n", dd_count);
    pr2serr("%" PRId64 "+%d records in\n", in_full - in_partial, in_partial);
    pr2serr("%" PRId64 "+%d records out\n", out_full - out_partial,
            out_partial);
}

static void
list_op_abbrevs()
{
    struct smp_val_name * vnp;

    pr2serr("  Valid operation abbreviations are:\n");
    for (vnp = op_abbrev; vnp->name; ++vnp)
        pr2serr("    %s\n", vnp->name);
}

static int fail_all_paths(int fd, int use_6_byte)
{
    unsigned char fail_paths_pg[308];
    struct rdac_legacy_page *rdac_page;
    struct rdac_expanded_page *rdac_page_exp;
    struct rdac_page_common *rdac_common = NULL;

    int res;
    char b[80];

    memset(fail_paths_pg, 0, 308);
    if (use_6_byte) {
        memcpy(fail_paths_pg, mode6_hdr, 4);
        memcpy(fail_paths_pg + 4, block_descriptor, 8);
        rdac_page = (struct rdac_legacy_page *)(fail_paths_pg + 4 + 8);
        rdac_page->page_code = RDAC_CONTROLLER_PAGE;
        rdac_page->page_length = RDAC_CONTROLLER_PAGE_LEN;
        rdac_common = &rdac_page->attr;
    } else {
        memcpy(fail_paths_pg, mode10_hdr, 8);
        rdac_page_exp = (struct rdac_expanded_page *)
                        (fail_paths_pg + 8);
        rdac_page_exp->page_code = RDAC_CONTROLLER_PAGE | 0x40;
        rdac_page_exp->subpage_code = 0x1;
        sg_put_unaligned_be16(EXPANDED_LUN_SPACE_PAGE_LEN,
                              rdac_page_exp->page_length + 0);
        rdac_common = &rdac_page_exp->attr;
    }

    rdac_common->current_mode_lsb =  RDAC_FAIL_ALL_PATHS;
    rdac_common->quiescence = RDAC_QUIESCENCE_TIME;
    rdac_common->options = RDAC_FORCE_QUIESCENCE;

    if (use_6_byte) {
        res = sg_ll_mode_select6(fd, 1 /* pf */, 0 /* sp */,
                                 fail_paths_pg, 118,
                                 1, (do_verbose ? 2 : 0));
    } else {
        res = sg_ll_mode_select10(fd, 1 /* pf */, 0 /* sp */,
                                  fail_paths_pg, 308,
                                  1, (do_verbose ? 2: 0));
    }

    switch (res) {
    case 0:
        if (do_verbose)
            pr2serr("fail paths successful\n");
        break;
    default:
        sg_get_category_sense_str(res, sizeof(b), b, do_verbose);
        pr2serr("fail paths failed: %s\n", b);
        break;
    }

    return res;
}

/* Allocate aligned memory (heap) starting on page boundary */
static unsigned char *
my_memalign(int length, unsigned char ** wrkBuffp, const struct opts_t * op)
{
    size_t psz;
    unsigned char * res;

#if defined(HAVE_SYSCONF) && defined(_SC_PAGESIZE)
    psz = sysconf(_SC_PAGESIZE); /* POSIX.1 (was getpagesize()) */
#elif defined(SG_LIB_WIN32)
    psz = win_pagesize();
#else
    psz = 4096;     /* give up, pick likely figure */
#endif

#ifdef HAVE_POSIX_MEMALIGN
    {
        int err;
        void * wp = NULL;

        err = posix_memalign(&wp, psz, length);
        if (err || (NULL == wp)) {
            pr2serr("posix_memalign: error [%d], out of memory?\n", err);
            return NULL;
        }
        memset(wp, 0, length);
        if (wrkBuffp)
            *wrkBuffp = (unsigned char *)wp;
        res = (unsigned char *)wp;
        if (op->verbose > 3)
            pr2serr("%s: posix, len=%d, wrkBuffp=%p, psz=%d, rp=%p\n",
                    __func__, length, (void *)*wrkBuffp, (int)psz,
                    (void *)res);
        return res;
    }
#else
    {
        unsigned char * wrkBuff;

        wrkBuff = (unsigned char*)calloc(length + psz, 1);
        if (NULL == wrkBuff) {
            if (wrkBuffp)
                *wrkBuffp = NULL;
            return NULL;
        } else if (wrkBuffp)
            *wrkBuffp = wrkBuff;
        res = (unsigned char *)(((uintptr_t)wrkBuff + psz - 1) &
                                (~(psz - 1)));
        if (op->verbose > 3)
            pr2serr("%s: hack, len=%d, wrkBuffp=%p, psz=%d, rp=%p\n",
                    __func__, length, (void *)*wrkBuffp, (int)psz,
                    (void *)res);
        return res;
    }
#endif
}

static int
ll_sync_cache_16(int sg_fd, int sync_nv, int immed, int group,
                 uint64_t lba, unsigned int num_lb, int to_secs,
                 int noisy, int verbose)
{
    int res, ret, k, sense_cat;
    unsigned char sc_cdb[SYNCHRONIZE_CACHE16_CMDLEN] =
    {   SYNCHRONIZE_CACHE16_CMD, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0
    };
    unsigned char sense_b[SENSE_BUFF_LEN];
    struct sg_pt_base * ptvp;

    if (sync_nv)
        sc_cdb[1] |= 4;       /* obsolete in sbc3r35d */
    if (immed)
        sc_cdb[1] |= 2;
    sg_put_unaligned_be64(lba, sc_cdb + 2);
    sc_cdb[14] = group & 0x1f;
    sg_put_unaligned_be32((uint32_t)num_lb, sc_cdb + 10);

    if (verbose) {
        pr2serr("    synchronize cache(16) cdb: ");
        for (k = 0; k < SYNCHRONIZE_CACHE16_CMDLEN; ++k)
            pr2serr("%02x ", sc_cdb[k]);
        pr2serr("\n");
    }
    ptvp = construct_scsi_pt_obj();
    if (NULL == ptvp) {
        pr2serr("synchronize cache(16): out of memory\n");
        return -1;
    }
    set_scsi_pt_cdb(ptvp, sc_cdb, sizeof(sc_cdb));
    set_scsi_pt_sense(ptvp, sense_b, sizeof(sense_b));
    res = do_scsi_pt(ptvp, sg_fd, to_secs, verbose);
    ret = sg_cmds_process_resp(ptvp, "synchronize cache(16)", res, 0,
                               sense_b, noisy, verbose, &sense_cat);
    if (-1 == ret)
        ;
    else if (-2 == ret) {
        switch (sense_cat) {
        case SG_LIB_CAT_RECOVERED:
        case SG_LIB_CAT_NO_SENSE:
            ret = 0;
            break;
        default:
            ret = sense_cat;
            break;
        }
    } else
        ret = 0;

    destruct_scsi_pt_obj(ptvp);
    return ret;
}

/* Invokes a SCSI REPORT TIMESTAMP command.  Return of 0 -> success,
 * various SG_LIB_CAT_* positive values or -1 -> other errors */
static int
sg_ll_rep_timestamp(int sg_fd, void * resp, int mx_resp_len, int * residp,
                    int noisy, int verbose)
{
    int k, ret, res, sense_cat;
    unsigned char rtCmdBlk[REP_TIMESTAMP_CMDLEN] =
          {SG_MAINTENANCE_IN, REP_TIMESTAMP_SA, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0};
    unsigned char sense_b[SENSE_BUFF_LEN];
    struct sg_pt_base * ptvp;

    sg_put_unaligned_be32((uint32_t)mx_resp_len, rtCmdBlk + 6);
    if (verbose) {
        pr2serr("    Report timestamp cdb: ");
        for (k = 0; k < REP_TIMESTAMP_CMDLEN; ++k)
            pr2serr("%02x ", rtCmdBlk[k]);
        pr2serr("\n");
    }

    ptvp = construct_scsi_pt_obj();
    if (NULL == ptvp) {
        pr2serr("%s: out of memory\n", __func__);
        return -1;
    }
    set_scsi_pt_cdb(ptvp, rtCmdBlk, sizeof(rtCmdBlk));
    set_scsi_pt_sense(ptvp, sense_b, sizeof(sense_b));
    set_scsi_pt_data_in(ptvp, (unsigned char *)resp, mx_resp_len);
    res = do_scsi_pt(ptvp, sg_fd, DEF_PT_TIMEOUT, verbose);
    ret = sg_cmds_process_resp(ptvp, "report timestamp", res, mx_resp_len,
                               sense_b, noisy, verbose, &sense_cat);
    if (-1 == ret)
        ;
    else if (-2 == ret) {
        switch (sense_cat) {
        case SG_LIB_CAT_RECOVERED:
        case SG_LIB_CAT_NO_SENSE:
            ret = 0;
            break;
        default:
            ret = sense_cat;
            break;
        }
    } else
        ret = 0;
    k = get_scsi_pt_resid(ptvp);
    if (residp)
        *residp = k;
    if ((verbose > 2) && ((mx_resp_len - k) > 0)) {
        pr2serr("Parameter data returned:\n");
        dStrHexErr((const char *)resp, mx_resp_len - k,
                   ((verbose > 3) ? -1 : 1));
    }
    destruct_scsi_pt_obj(ptvp);
    return ret;
}

static void
print_modes(void)
{
    const struct mode_s *mp;

    pr2serr("The modes parameter argument can be numeric (hex or decimal)\n"
            "or symbolic:\n");
    for (mp = modes; mp->mode_string; ++mp) {
        pr2serr(" %2d (0x%02x)  %-16s%s\n", mp->mode, mp->mode,
                mp->mode_string, mp->comment);
    }
}

/* Invokes the SET TIMESTAMP command.  Return of 0 -> success, various
 * SG_LIB_CAT_* positive values or -1 -> other errors */
static int
sg_ll_set_timestamp(int sg_fd, void * paramp, int param_len, int noisy,
                    int verbose)
{
    int k, ret, res, sense_cat;
    unsigned char stCmdBlk[SET_TIMESTAMP_CMDLEN] =
          {SG_MAINTENANCE_OUT, SET_TIMESTAMP_SA, 0, 0,  0, 0, 0, 0,
           0, 0, 0, 0};
    unsigned char sense_b[SENSE_BUFF_LEN];
    struct sg_pt_base * ptvp;

    sg_put_unaligned_be32(param_len, stCmdBlk + 6);
    if (verbose) {
        pr2serr("    Set timestamp cdb: ");
        for (k = 0; k < SET_TIMESTAMP_CMDLEN; ++k)
            pr2serr("%02x ", stCmdBlk[k]);
        pr2serr("\n");
        if ((verbose > 1) && paramp && param_len) {
            pr2serr("    set timestamp parameter list:\n");
            dStrHexErr((const char *)paramp, param_len, -1);
        }
    }

    ptvp = construct_scsi_pt_obj();
    if (NULL == ptvp) {
        pr2serr("%s: out of memory\n", __func__);
        return -1;
    }
    set_scsi_pt_cdb(ptvp, stCmdBlk, sizeof(stCmdBlk));
    set_scsi_pt_sense(ptvp, sense_b, sizeof(sense_b));
    set_scsi_pt_data_out(ptvp, (unsigned char *)paramp, param_len);
    res = do_scsi_pt(ptvp, sg_fd, DEF_PT_TIMEOUT, verbose);
    ret = sg_cmds_process_resp(ptvp, "set timestamp", res, 0, sense_b, noisy,
                               verbose, &sense_cat);
    if (-1 == ret)
        ;
    else if (-2 == ret) {
        switch (sense_cat) {
        case SG_LIB_CAT_RECOVERED:
        case SG_LIB_CAT_NO_SENSE:
            ret = 0;
            break;
        default:
            ret = sense_cat;
            break;
        }
    } else
        ret = 0;
    destruct_scsi_pt_obj(ptvp);
    return ret;
}

static void
decode_all_sa_s(const unsigned char * rabp, int len, const struct opts_t * op)
{
    if (op->do_hex && (2 != op->do_hex)) {
        dStrHex((const char *)rabp, len, ((1 == op->do_hex) ? 1 : -1));
        return;
    }
    switch (op->sa) {
    case RA_ATTR_VAL_SA:
        decode_attr_vals(rabp + 4, len - 4, op);
        break;
    case RA_ATTR_LIST_SA:
        decode_attr_list(rabp + 4, len - 4, false, op);
        break;
    case RA_LV_LIST_SA:
        if ((0 == op->quiet) || op->verbose)
            printf("Logical volume list:\n");
        if (len < 4) {
            pr2serr(">>> response length unexpectedly short: %d bytes\n",
                    len);
            break;
        }
        printf("  First logical volume number: %u\n", rabp[2]);
        printf("  Number of logical volumes available: %u\n", rabp[3]);
        break;
    case RA_PART_LIST_SA:
        if ((0 == op->quiet) || op->verbose)
            printf("Partition number list:\n");
        if (len < 4) {
            pr2serr(">>> response length unexpectedly short: %d bytes\n",
                    len);
            break;
        }
        printf("  First partition number: %u\n", rabp[2]);
        printf("  Number of partitions available: %u\n", rabp[3]);
        break;
    case RA_SMC2_SA:
        printf("Used by SMC-2, not information, output in hex:\n");
        dStrHex((const char *)rabp, len, 0);
        break;
    case RA_SUP_ATTR_SA:
        decode_attr_list(rabp + 4, len - 4, true, op);
        break;
    default:
        printf("Unrecognized service action [0x%x], response in hex:\n",
               op->sa);
        dStrHex((const char *)rabp, len, 0);
        break;
    }
}

/* Invokes a SCSI BACKGROUND CONTROL command (SBC-4).  Return of 0 -> success,
 * various SG_LIB_CAT_* positive values or -1 -> other errors */
static int
sg_ll_background_control(int sg_fd, unsigned int bo_ctl, unsigned int bo_time,
                         bool noisy, int verbose)
{
    int k, ret, res, sense_cat;
    uint8_t bcCDB[16] = {SG_SERVICE_ACTION_IN_16,
           BACKGROUND_CONTROL_SA, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,
           0, 0, 0, 0};
    uint8_t sense_b[SENSE_BUFF_LEN];
    struct sg_pt_base * ptvp;

    if (bo_ctl)
        bcCDB[2] |= (bo_ctl & 0x3) << 6;
    if (bo_time)
        bcCDB[3] = bo_time;
    if (verbose) {
        pr2serr("    %s cdb: ", cmd_name);
        for (k = 0; k < (int)sizeof(bcCDB); ++k)
            pr2serr("%02x ", bcCDB[k]);
        pr2serr("\n");
    }

    ptvp = construct_scsi_pt_obj();
    if (NULL == ptvp) {
        pr2serr("%s: out of memory\n", cmd_name);
        return -1;
    }
    set_scsi_pt_cdb(ptvp, bcCDB, sizeof(bcCDB));
    set_scsi_pt_sense(ptvp, sense_b, sizeof(sense_b));
    res = do_scsi_pt(ptvp, sg_fd, DEF_PT_TIMEOUT, verbose);
    ret = sg_cmds_process_resp(ptvp, cmd_name, res, SG_NO_DATA_IN, sense_b,
                               noisy, verbose, &sense_cat);
    if (-1 == ret)
        ret = sg_convert_errno(get_scsi_pt_os_err(ptvp));
    else if (-2 == ret) {
        switch (sense_cat) {
        case SG_LIB_CAT_RECOVERED:
        case SG_LIB_CAT_NO_SENSE:
            ret = 0;
            break;
        default:
            ret = sense_cat;
            break;
        }
    } else
        ret = 0;
    destruct_scsi_pt_obj(ptvp);
    return ret;
}

static void
print_modes(void)
{
    const struct mode_s * mp;

    pr2serr("The modes parameter argument can be numeric (hex or decimal)\n"
            "or symbolic:\n");
    for (mp = mode_arr; mp->mode_string; ++mp) {
        pr2serr(" %3d [0x%02x]  %-18s%s\n", mp->mode, mp->mode,
                mp->mode_string, mp->comment);
    }
    pr2serr("\nAdditionally '--bpw=<val>,act' does a activate deferred "
            "microcode after a\nsuccessful multipart dmc_offs_defer mode "
            "download.\n");
}

static void
usage(void)
{
    pr2serr("Usage: smp_rep_phy_sata [--affiliation=AC] [--help] [--hex]\n"
            "                        [--interface=PARAMS] [--phy=ID] "
            "[--raw]\n"
            "                        [--sa=SAS_ADDR] [--verbose] [--version] "
            "[--zero]\n"
            "                        SMP_DEVICE[,N]\n"
            "  where:\n"
            "    --affiliation=AC|-a AC    relative identifier of affiliation "
            "context\n"
            "                              (def: 0)\n"
            "    --help|-h            print out usage message\n"
            "    --hex|-H             print response in hexadecimal\n"
            "    --interface=PARAMS|-I PARAMS    specify or override "
            "interface\n"
            "    --phy=ID|-p ID       phy identifier (def: 0)\n"
            "    --raw|-r             output response in binary\n"
            "    --sa=SAS_ADDR|-s SAS_ADDR    SAS address of SMP "
            "target (use leading\n"
            "                                 '0x' or trailing 'h'). "
            "Depending on\n"
            "                                 the interface, may not be "
            "needed\n"
            "    --verbose|-v         increase verbosity\n"
            "    --version|-V         print version string and exit\n"
            "    --zero|-z            zero Allocated Response Length "
            "field,\n"
            "                         may be required prior to SAS-2\n\n"
            "Performs a SMP REPORT PHY SATA function\n"
           );
}

static int
skip(int fd, off_t offset)
{
    off_t remain;
    char buffer[512];

    if (lseek(fd, offset, SEEK_SET) >= 0) {
        return 0;
    }

    // lseek failed; fall back to reading and discarding data
    remain = offset;
    while (remain > 0) {
        ssize_t amount, done;
        amount = (remain < (off_t)sizeof(buffer)) ? remain
                                         : (off_t)sizeof(buffer);
        done = read(fd, buffer, amount);
        if (done < 0) {
            perror("Error reading input data");
            return SG_LIB_FILE_ERROR;
        } else if (done == 0) {
            pr2serr("EOF on input file/stream\n");
            return SG_LIB_FILE_ERROR;
        } else {
            remain -= done;
        }
    }

    return 0;
}

static void
usage()
{
    pr2serr("Usage: sg_read_buffer [--16] [--help] [--hex] [--id=ID] "
            "[--length=LEN]\n"
            "                      [--long] [--mode=MO] [--offset=OFF] "
            "[--raw]\n"
            "                      [--readonly] [--specific=MS] [--verbose] "
            "[--version]\n"
            "                      DEVICE\n"
            "  where:\n"
            "    --16|-L             issue READ BUFFER(16) (def: 10)\n"
            "    --help|-h           print out usage message\n"
            "    --hex|-H            print output in hex\n"
            "    --id=ID|-i ID       buffer identifier (0 (default) to 255)\n"
            "    --length=LEN|-l LEN    length in bytes to read (def: 4)\n"
            "    --long|-L           issue READ BUFFER(16) (def: 10)\n"
            "    --mode=MO|-m MO     read buffer mode, MO is number or "
            "acronym (def: 0)\n"
            "    --offset=OFF|-o OFF    buffer offset (unit: bytes, def: 0)\n"
            "    --raw|-r            output response to stdout\n"
            "    --readonly|-R       open DEVICE read-only (def: read-write)\n"
            "    --specific=MS|-S MS    mode specific value; 3 bit field (0 "
            "to 7)\n"
            "    --verbose|-v        increase verbosity\n"
            "    --version|-V        print version string and exit\n\n"
            "Performs a SCSI READ BUFFER (10 or 16) command. Use '-m xxx' to "
            "list\navailable modes. Numbers given in options are decimal "
            "unless they have\na hex indicator (e.g. a leading '0x').\n"
           );
}