/* A utility program for copying files. Specialised for "files" that
 * represent devices that understand the SCSI command set.
 *
 * Copyright (C) 1999 - 2018 D. Gilbert and P. Allworth
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is a specialisation of the Unix "dd" command in which
 * either the input or the output file is a scsi generic device, raw
 * device, a block device or a normal file. The block size ('bs') is
 * assumed to be 512 if not given. This program complains if 'ibs' or
 * 'obs' are given with a value that differs from 'bs' (or the default 512).
 * If 'if' is not given or 'if=-' then stdin is assumed. If 'of' is
 * not given or 'of=-' then stdout assumed.
 *
 * A non-standard argument "bpt" (blocks per transfer) is added to control
 * the maximum number of blocks in each transfer. The default value is 128.
 * For example if "bs=512" and "bpt=32" then a maximum of 32 blocks (16 KiB
 * in this case) is transferred to or from the sg device in a single SCSI
 * command. The actual size of the SCSI READ or WRITE command block can be
 * selected with the "cdbsz" argument.
 *
 * This version is designed for the linux kernel 2.4, 2.6, 3 and 4 series.
 */

#define _XOPEN_SOURCE 600
#ifndef _GNU_SOURCE
#define _GNU_SOURCE 1
#endif

#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <stdbool.h>
#include <string.h>
#include <signal.h>
#include <ctype.h>
#include <errno.h>
#include <limits.h>
#define __STDC_FORMAT_MACROS 1
#include <inttypes.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/file.h>
#include <sys/sysmacros.h>
#ifndef major
#include <sys/types.h>
#endif
#include <linux/major.h>        /* for MEM_MAJOR, SCSI_GENERIC_MAJOR, etc */
#include <linux/fs.h>           /* for BLKSSZGET and friends */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "sg_lib.h"
#include "sg_cmds_basic.h"
#include "sg_cmds_extra.h"
#include "sg_io_linux.h"
#include "sg_unaligned.h"
#include "sg_pr2serr.h"

static const char * version_str = "6.04 20180811";


#define ME "sg_dd: "


#define STR_SZ 1024
#define INOUTF_SZ 512
#define EBUFF_SZ 768

#define DEF_BLOCK_SIZE 512
#define DEF_BLOCKS_PER_TRANSFER 128
#define DEF_BLOCKS_PER_2048TRANSFER 32
#define DEF_SCSI_CDBSZ 10
#define MAX_SCSI_CDBSZ 16

#define DEF_MODE_CDB_SZ 10
#define DEF_MODE_RESP_LEN 252
#define RW_ERR_RECOVERY_MP 1
#define CACHING_MP 8
#define CONTROL_MP 0xa

#define SENSE_BUFF_LEN 64       /* Arbitrary, could be larger */
#define READ_CAP_REPLY_LEN 8
#define RCAP16_REPLY_LEN 32
#define READ_LONG_OPCODE 0x3E
#define READ_LONG_CMD_LEN 10
#define READ_LONG_DEF_BLK_INC 8

#define DEF_TIMEOUT 60000       /* 60,000 millisecs == 60 seconds */

#ifndef RAW_MAJOR
#define RAW_MAJOR 255   /*unlikey value */
#endif

#define SG_LIB_FLOCK_ERR 90

#define FT_OTHER 1              /* filetype is probably normal */
#define FT_SG 2                 /* filetype is sg char device or supports
                                   SG_IO ioctl */
#define FT_RAW 4                /* filetype is raw char device */
#define FT_DEV_NULL 8           /* either "/dev/null" or "." as filename */
#define FT_ST 16                /* filetype is st char device (tape) */
#define FT_BLOCK 32             /* filetype is block device */
#define FT_FIFO 64              /* filetype is a fifo (name pipe) */
#define FT_ERROR 128            /* couldn't "stat" file */

#define DEV_NULL_MINOR_NUM 3

/* If platform does not support O_DIRECT then define it harmlessly */
#ifndef O_DIRECT
#define O_DIRECT 0
#endif

#define MIN_RESERVED_SIZE 8192

#define MAX_UNIT_ATTENTIONS 10
#define MAX_ABORTED_CMDS 256

static int sum_of_resids = 0;

static int64_t dd_count = -1;
static int64_t req_count = 0;
static int64_t in_full = 0;
static int in_partial = 0;
static int64_t out_full = 0;
static int out_partial = 0;
static int64_t out_sparse_num = 0;
static int recovered_errs = 0;
static int unrecovered_errs = 0;
static int read_longs = 0;
static int num_retries = 0;
static int dry_run = 0;

static bool do_time = false;
static bool start_tm_valid = false;
static int verbose = 0;
static int blk_sz = 0;
static int max_uas = MAX_UNIT_ATTENTIONS;
static int max_aborted = MAX_ABORTED_CMDS;
static int coe_limit = 0;
static int coe_count = 0;
static struct timeval start_tm;

static uint8_t * zeros_buff = NULL;
static uint8_t * free_zeros_buff = NULL;
static int read_long_blk_inc = READ_LONG_DEF_BLK_INC;

static const char * proc_allow_dio = "/proc/scsi/sg/allow_dio";

struct flags_t {
    bool append;
    bool dio;
    bool direct;
    bool dpo;
    bool dsync;
    bool excl;
    bool flock;
    bool fua;
    bool sgio;
    bool sparse;
    int cdbsz;
    int coe;
    int nocache;
    int pdt;
    int retries;
};

static struct flags_t iflag;
static struct flags_t oflag;

static void calc_duration_throughput(bool contin);


static void
install_handler(int sig_num, void (*sig_handler) (int sig))
{
    struct sigaction sigact;
    sigaction (sig_num, NULL, &sigact);
    if (sigact.sa_handler != SIG_IGN)
    {
        sigact.sa_handler = sig_handler;
        sigemptyset (&sigact.sa_mask);
        sigact.sa_flags = 0;
        sigaction (sig_num, &sigact, NULL);
    }
}


static void
print_stats(const char * str)
{
    if (0 != dd_count)
        pr2serr("  remaining block count=%" PRId64 "\n", dd_count);
    pr2serr("%s%" PRId64 "+%d records in\n", str, in_full - in_partial,
            in_partial);
    pr2serr("%s%" PRId64 "+%d records out\n", str, out_full - out_partial,
            out_partial);
    if (oflag.sparse)
        pr2serr("%s%" PRId64 " bypassed records out\n", str, out_sparse_num);
    if (recovered_errs > 0)
        pr2serr("%s%d recovered errors\n", str, recovered_errs);
    if (num_retries > 0)
        pr2serr("%s%d retries attempted\n", str, num_retries);
    if (iflag.coe || oflag.coe) {
        pr2serr("%s%d unrecovered errors\n", str, unrecovered_errs);
        pr2serr("%s%d read_longs fetched part of unrecovered read errors\n",
                str, read_longs);
    } else if (unrecovered_errs)
        pr2serr("%s%d unrecovered error(s)\n", str, unrecovered_errs);
}


static void
interrupt_handler(int sig)
{
    struct sigaction sigact;

    sigact.sa_handler = SIG_DFL;
    sigemptyset(&sigact.sa_mask);
    sigact.sa_flags = 0;
    sigaction(sig, &sigact, NULL);
    pr2serr("Interrupted by signal,");
    if (do_time)
        calc_duration_throughput(false);
    print_stats("");
    kill(getpid (), sig);
}


static void
siginfo_handler(int sig)
{
    if (sig) { ; }      /* unused, dummy to suppress warning */
    pr2serr("Progress report, continuing ...\n");
    if (do_time)
        calc_duration_throughput(true);
    print_stats("  ");
}

static bool bsg_major_checked = false;
static int bsg_major = 0;

static void
find_bsg_major(void)
{
    int n;
    char *cp;
    FILE *fp;
    const char *proc_devices = "/proc/devices";
    char a[128];
    char b[128];

    if (NULL == (fp = fopen(proc_devices, "r"))) {
        if (verbose)
            pr2serr("fopen %s failed: %s\n", proc_devices, strerror(errno));
        return;
    }
    while ((cp = fgets(b, sizeof(b), fp))) {
        if ((1 == sscanf(b, "%126s", a)) &&
            (0 == memcmp(a, "Character", 9)))
            break;
    }
    while (cp && (cp = fgets(b, sizeof(b), fp))) {
        if (2 == sscanf(b, "%d %126s", &n, a)) {
            if (0 == strcmp("bsg", a)) {
                bsg_major = n;
                break;
            }
        } else
            break;
    }
    if (verbose > 5) {
        if (cp)
            pr2serr("found bsg_major=%d\n", bsg_major);
        else
            pr2serr("found no bsg char device in %s\n", proc_devices);
    }
    fclose(fp);
}


static int
dd_filetype(const char * filename)
{
    size_t len = strlen(filename);
    struct stat st;

    if ((1 == len) && ('.' == filename[0]))
        return FT_DEV_NULL;
    if (stat(filename, &st) < 0)
        return FT_ERROR;
    if (S_ISCHR(st.st_mode)) {
        /* major() and minor() defined in sys/sysmacros.h */
        if ((MEM_MAJOR == major(st.st_rdev)) &&
            (DEV_NULL_MINOR_NUM == minor(st.st_rdev)))
            return FT_DEV_NULL;
        if (RAW_MAJOR == major(st.st_rdev))
            return FT_RAW;
        if (SCSI_GENERIC_MAJOR == major(st.st_rdev))
            return FT_SG;
        if (SCSI_TAPE_MAJOR == major(st.st_rdev))
            return FT_ST;
        if (! bsg_major_checked) {
            bsg_major_checked = true;
            find_bsg_major();
        }
        if (bsg_major == (int)major(st.st_rdev))
            return FT_SG;
    } else if (S_ISBLK(st.st_mode))
        return FT_BLOCK;
    else if (S_ISFIFO(st.st_mode))
        return FT_FIFO;
    return FT_OTHER;
}


static char *
dd_filetype_str(int ft, char * buff)
{
    int off = 0;

    if (FT_DEV_NULL & ft)
        off += sg_scnpr(buff + off, 32, "null device ");
    if (FT_SG & ft)
        off += sg_scnpr(buff + off, 32, "SCSI generic (sg) device ");
    if (FT_BLOCK & ft)
        off += sg_scnpr(buff + off, 32, "block device ");
    if (FT_FIFO & ft)
        off += sg_scnpr(buff + off, 32, "fifo (named pipe) ");
    if (FT_ST & ft)
        off += sg_scnpr(buff + off, 32, "SCSI tape device ");
    if (FT_RAW & ft)
        off += sg_scnpr(buff + off, 32, "raw device ");
    if (FT_OTHER & ft)
        off += sg_scnpr(buff + off, 32, "other (perhaps ordinary file) ");
    if (FT_ERROR & ft)
        sg_scnpr(buff + off, 32, "unable to 'stat' file ");
    return buff;
}


static void
usage()
{
    pr2serr("Usage: sg_dd  [bs=BS] [count=COUNT] [ibs=BS] [if=IFILE] "
            "[iflag=FLAGS]\n"
            "              [obs=BS] [of=OFILE] [oflag=FLAGS] "
            "[seek=SEEK] [skip=SKIP]\n"
            "              [--dry-run] [--help] [--verbose] [--version]\n\n"
            "              [blk_sgio=0|1] [bpt=BPT] [cdbsz=6|10|12|16] "
            "[coe=0|1|2|3]\n"
            "              [coe_limit=CL] [dio=0|1] [odir=0|1] "
            "[of2=OFILE2] [retries=RETR]\n"
            "              [sync=0|1] [time=0|1] [verbose=VERB]\n"
            "  where:\n"
            "    blk_sgio    0->block device use normal I/O(def), 1->use "
            "SG_IO\n"
            "    bpt         is blocks_per_transfer (default is 128 or 32 "
            "when BS>=2048)\n"
            "    bs          block size (default is 512)\n");
    pr2serr("    cdbsz       size of SCSI READ or WRITE cdb (default is "
            "10)\n"
            "    coe         0->exit on error (def), 1->continue on sg "
            "error (zero\n"
            "                fill), 2->also try read_long on unrecovered "
            "reads,\n"
            "                3->and set the CORRCT bit on the read long\n"
            "    coe_limit   limit consecutive 'bad' blocks on reads to CL "
            "times\n"
            "                when COE>1 (default: 0 which is no limit)\n"
            "    count       number of blocks to copy (def: device size)\n"
            "    dio         for direct IO, 1->attempt, 0->indirect IO (def)\n"
            "    ibs         input block size (if given must be same as "
            "'bs=')\n"
            "    if          file or device to read from (def: stdin)\n"
            "    iflag       comma separated list from: [coe,dio,direct,"
            "dpo,dsync,excl,\n"
            "                flock,fua,nocache,null,sgio]\n"
            "    obs         output block size (if given must be same as "
            "'bs=')\n"
            "    odir        1->use O_DIRECT when opening block dev, "
            "0->don't(def)\n"
            "    of          file or device to write to (def: stdout), "
            "OFILE of '.'\n");
    pr2serr("                treated as /dev/null\n"
            "    of2         additional output file (def: /dev/null), "
            "OFILE2 should be\n"
            "                normal file or pipe\n"
            "    oflag       comma separated list from: [append,coe,dio,"
            "direct,dpo,\n"
            "                dsync,excl,flock,fua,nocache,null,sgio,"
            "sparse]\n"
            "    retries     retry sgio errors RETR times (def: 0)\n"
            "    seek        block position to start writing to OFILE\n"
            "    skip        block position to start reading from IFILE\n"
            "    sync        0->no sync(def), 1->SYNCHRONIZE CACHE on "
            "OFILE after copy\n"
            "    time        0->no timing(def), 1->time plus calculate "
            "throughput\n"
            "    verbose     0->quiet(def), 1->some noise, 2->more noise, "
            "etc\n"
            "    --dry-run    do preparation but bypass copy (or read)\n"
            "    --help      print out this usage message then exit\n"
            "    --verbose   same as 'verbose=1', can be used multiple "
            "times\n"
            "    --version   print version information then exit\n\n"
            "copy from IFILE to OFILE, similar to dd command; "
            "specialized for SCSI devices\n");
}


/* Return of 0 -> success, see sg_ll_read_capacity*() otherwise */
static int
scsi_read_capacity(int sg_fd, int64_t * num_sect, int * sect_sz)
{
    int res, verb;
    unsigned int ui;
    uint8_t rcBuff[RCAP16_REPLY_LEN];

    verb = (verbose ? verbose - 1: 0);
    res = sg_ll_readcap_10(sg_fd, false, 0, rcBuff, READ_CAP_REPLY_LEN, true,
                           verb);
    if (0 != res)
        return res;

    if ((0xff == rcBuff[0]) && (0xff == rcBuff[1]) && (0xff == rcBuff[2]) &&
        (0xff == rcBuff[3])) {
        int64_t ls;

        res = sg_ll_readcap_16(sg_fd, false, 0, rcBuff, RCAP16_REPLY_LEN,
                               true, verb);
        if (0 != res)
            return res;
        ls = (int64_t)sg_get_unaligned_be64(rcBuff);
        *num_sect = ls + 1;
        *sect_sz = (int)sg_get_unaligned_be32(rcBuff + 8);
    } else {
        ui = sg_get_unaligned_be32(rcBuff);
        /* take care not to sign extend values > 0x7fffffff */
        *num_sect = (int64_t)ui + 1;
        *sect_sz = (int)sg_get_unaligned_be32(rcBuff + 4);
    }
    if (verbose)
        pr2serr("      number of blocks=%" PRId64 " [0x%" PRIx64 "], "
                "block size=%d\n", *num_sect, *num_sect, *sect_sz);
    return 0;
}


/* Return of 0 -> success, -1 -> failure. BLKGETSIZE64, BLKGETSIZE and */
/* BLKSSZGET macros problematic (from <linux/fs.h> or <sys/mount.h>). */
static int
read_blkdev_capacity(int sg_fd, int64_t * num_sect, int * sect_sz)
{
#ifdef BLKSSZGET
    if ((ioctl(sg_fd, BLKSSZGET, sect_sz) < 0) && (*sect_sz > 0)) {
        perror("BLKSSZGET ioctl error");
        return -1;
    } else {
 #ifdef BLKGETSIZE64
        uint64_t ull;

        if (ioctl(sg_fd, BLKGETSIZE64, &ull) < 0) {

            perror("BLKGETSIZE64 ioctl error");
            return -1;
        }
        *num_sect = ((int64_t)ull / (int64_t)*sect_sz);
        if (verbose)
            pr2serr("      [bgs64] number of blocks=%" PRId64 " [0x%" PRIx64
                    "], block size=%d\n", *num_sect, *num_sect, *sect_sz);
 #else
        unsigned long ul;

        if (ioctl(sg_fd, BLKGETSIZE, &ul) < 0) {
            perror("BLKGETSIZE ioctl error");
            return -1;
        }
        *num_sect = (int64_t)ul;
        if (verbose)
            pr2serr("      [bgs] number of blocks=%" PRId64 " [0x%" PRIx64
                    "],  block size=%d\n", *num_sect, *num_sect, *sect_sz);
 #endif
    }
    return 0;
#else
    if (verbose)
        pr2serr("      BLKSSZGET+BLKGETSIZE ioctl not available\n");
    *num_sect = 0;
    *sect_sz = 0;
    return -1;
#endif
}


static int
sg_build_scsi_cdb(uint8_t * cdbp, int cdb_sz, unsigned int blocks,
                  int64_t start_block, bool write_true, bool fua, bool dpo)
{
    int sz_ind;
    int rd_opcode[] = {0x8, 0x28, 0xa8, 0x88};
    int wr_opcode[] = {0xa, 0x2a, 0xaa, 0x8a};

    memset(cdbp, 0, cdb_sz);
    if (dpo)
        cdbp[1] |= 0x10;
    if (fua)
        cdbp[1] |= 0x8;
    switch (cdb_sz) {
    case 6:
        sz_ind = 0;
        cdbp[0] = (uint8_t)(write_true ? wr_opcode[sz_ind] :
                                               rd_opcode[sz_ind]);
        sg_put_unaligned_be24(0x1fffff & start_block, cdbp + 1);
        cdbp[4] = (256 == blocks) ? 0 : (uint8_t)blocks;
        if (blocks > 256) {
            pr2serr(ME "for 6 byte commands, maximum number of blocks is "
                    "256\n");
            return 1;
        }
        if ((start_block + blocks - 1) & (~0x1fffff)) {
            pr2serr(ME "for 6 byte commands, can't address blocks beyond "
                    "%d\n", 0x1fffff);
            return 1;
        }
        if (dpo || fua) {
            pr2serr(ME "for 6 byte commands, neither dpo nor fua bits "
                    "supported\n");
            return 1;
        }
        break;
    case 10:
        sz_ind = 1;
        cdbp[0] = (uint8_t)(write_true ? wr_opcode[sz_ind] :
                                               rd_opcode[sz_ind]);
        sg_put_unaligned_be32(start_block, cdbp + 2);
        sg_put_unaligned_be16(blocks, cdbp + 7);
        if (blocks & (~0xffff)) {
            pr2serr(ME "for 10 byte commands, maximum number of blocks is "
                    "%d\n", 0xffff);
            return 1;
        }
        break;
    case 12:
        sz_ind = 2;
        cdbp[0] = (uint8_t)(write_true ? wr_opcode[sz_ind] :
                                               rd_opcode[sz_ind]);
        sg_put_unaligned_be32(start_block, cdbp + 2);
        sg_put_unaligned_be32(blocks, cdbp + 6);
        break;
    case 16:
        sz_ind = 3;
        cdbp[0] = (uint8_t)(write_true ? wr_opcode[sz_ind] :
                                               rd_opcode[sz_ind]);
        sg_put_unaligned_be64(start_block, cdbp + 2);
        sg_put_unaligned_be32(blocks, cdbp + 10);
        break;
    default:
        pr2serr(ME "expected cdb size of 6, 10, 12, or 16 but got %d\n",
                cdb_sz);
        return 1;
    }
    return 0;
}


/* 0 -> successful, SG_LIB_SYNTAX_ERROR -> unable to build cdb,
   SG_LIB_CAT_UNIT_ATTENTION -> try again,
   SG_LIB_CAT_MEDIUM_HARD_WITH_INFO -> 'io_addrp' written to,
   SG_LIB_CAT_MEDIUM_HARD -> no info field,
   SG_LIB_CAT_NOT_READY, SG_LIB_CAT_ABORTED_COMMAND,
   -2 -> ENOMEM
   -1 other errors */
static int
sg_read_low(int sg_fd, uint8_t * buff, int blocks, int64_t from_block,
            int bs, const struct flags_t * ifp, bool * diop,
            uint64_t * io_addrp)
{
    bool info_valid;
    int res, k, slen;
    const uint8_t * sbp;
    uint8_t rdCmd[MAX_SCSI_CDBSZ];
    uint8_t senseBuff[SENSE_BUFF_LEN];
    struct sg_io_hdr io_hdr;

    if (sg_build_scsi_cdb(rdCmd, ifp->cdbsz, blocks, from_block, false,
                          ifp->fua, ifp->dpo)) {
        pr2serr(ME "bad rd cdb build, from_block=%" PRId64 ", blocks=%d\n",
                from_block, blocks);
        return SG_LIB_SYNTAX_ERROR;
    }

    memset(&io_hdr, 0, sizeof(struct sg_io_hdr));
    io_hdr.interface_id = 'S';
    io_hdr.cmd_len = ifp->cdbsz;
    io_hdr.cmdp = rdCmd;
    io_hdr.dxfer_direction = SG_DXFER_FROM_DEV;
    io_hdr.dxfer_len = bs * blocks;
    io_hdr.dxferp = buff;
    io_hdr.mx_sb_len = SENSE_BUFF_LEN;
    io_hdr.sbp = senseBuff;
    io_hdr.timeout = DEF_TIMEOUT;
    io_hdr.pack_id = (int)from_block;
    if (diop && *diop)
        io_hdr.flags |= SG_FLAG_DIRECT_IO;

    if (verbose > 2) {
        pr2serr("    read cdb: ");
        for (k = 0; k < ifp->cdbsz; ++k)
            pr2serr("%02x ", rdCmd[k]);
        pr2serr("\n");
    }
    while (((res = ioctl(sg_fd, SG_IO, &io_hdr)) < 0) &&
           ((EINTR == errno) || (EAGAIN == errno)))
        ;
    if (res < 0) {
        if (ENOMEM == errno)
            return -2;
        perror("reading (SG_IO) on sg device, error");
        return -1;
    }
    if (verbose > 2)
        pr2serr("      duration=%u ms\n", io_hdr.duration);
    res = sg_err_category3(&io_hdr);
    sbp = io_hdr.sbp;
    slen = io_hdr.sb_len_wr;
    switch (res) {
    case SG_LIB_CAT_CLEAN:
        break;
    case SG_LIB_CAT_RECOVERED:
        ++recovered_errs;
        info_valid = sg_get_sense_info_fld(sbp, slen, io_addrp);
        if (info_valid) {
            pr2serr("    lba of last recovered error in this READ=0x%" PRIx64
                    "\n", *io_addrp);
            if (verbose > 1)
                sg_chk_n_print3("reading", &io_hdr, true);
        } else {
            pr2serr("Recovered error: [no info] reading from block=0x%" PRIx64
                    ", num=%d\n", from_block, blocks);
            sg_chk_n_print3("reading", &io_hdr, verbose > 1);
        }
        break;
    case SG_LIB_CAT_ABORTED_COMMAND:
    case SG_LIB_CAT_UNIT_ATTENTION:
        sg_chk_n_print3("reading", &io_hdr, verbose > 1);
        return res;
    case SG_LIB_CAT_MEDIUM_HARD:
        if (verbose > 1)
            sg_chk_n_print3("reading", &io_hdr, verbose > 1);
        ++unrecovered_errs;
        info_valid = sg_get_sense_info_fld(sbp, slen, io_addrp);
        /* MMC devices don't necessarily set VALID bit */
        if (info_valid || ((5 == ifp->pdt) && (*io_addrp > 0)))
            return SG_LIB_CAT_MEDIUM_HARD_WITH_INFO;
        else {
            pr2serr("Medium, hardware or blank check error but no lba of "
                    "failure in sense\n");
            return res;
        }
        break;
    case SG_LIB_CAT_NOT_READY:
        ++unrecovered_errs;
        if (verbose > 0)
            sg_chk_n_print3("reading", &io_hdr, verbose > 1);
        return res;
    case SG_LIB_CAT_ILLEGAL_REQ:
        if (5 == ifp->pdt) {    /* MMC READs can go down this path */
            bool ili;
            struct sg_scsi_sense_hdr ssh;

            if (verbose > 1)
                sg_chk_n_print3("reading", &io_hdr, verbose > 1);
            if (sg_scsi_normalize_sense(sbp, slen, &ssh) &&
                (0x64 == ssh.asc) && (0x0 == ssh.ascq)) {
                if (sg_get_sense_filemark_eom_ili(sbp, slen, NULL, NULL,
                                                  &ili) && ili) {
                    sg_get_sense_info_fld(sbp, slen, io_addrp);
                    if (*io_addrp > 0) {
                        ++unrecovered_errs;
                        return SG_LIB_CAT_MEDIUM_HARD_WITH_INFO;
                    } else
                        pr2serr("MMC READ gave 'illegal mode for this track' "
                                "and ILI but no LBA of failure\n");
                }
                ++unrecovered_errs;
                return SG_LIB_CAT_MEDIUM_HARD;
            }
        }
#if defined(__GNUC__)
#if (__GNUC__ >= 7)
        __attribute__((fallthrough));
        /* FALL THROUGH */
#endif
#endif
    default:
        ++unrecovered_errs;
        if (verbose > 0)
            sg_chk_n_print3("reading", &io_hdr, verbose > 1);
        return res;
    }
    if (diop && *diop &&
        ((io_hdr.info & SG_INFO_DIRECT_IO_MASK) != SG_INFO_DIRECT_IO))
        *diop = false;      /* flag that dio not done (completely) */
    sum_of_resids += io_hdr.resid;
    return 0;
}


/* 0 -> successful, SG_LIB_SYNTAX_ERROR -> unable to build cdb,
   SG_LIB_CAT_UNIT_ATTENTION -> try again, SG_LIB_CAT_NOT_READY,
   SG_LIB_CAT_MEDIUM_HARD, SG_LIB_CAT_ABORTED_COMMAND,
   -2 -> ENOMEM, -1 other errors */
static int
sg_read(int sg_fd, uint8_t * buff, int blocks, int64_t from_block,
        int bs, struct flags_t * ifp, bool * diop, int * blks_readp)
{
    bool may_coe = false;
    bool repeat;
    int res, blks, xferred;
    int ret = 0;
    int retries_tmp;
    uint64_t io_addr;
    int64_t lba;
    uint8_t * bp;

    retries_tmp = ifp->retries;
    for (xferred = 0, blks = blocks, lba = from_block, bp = buff;
         blks > 0; blks = blocks - xferred) {
        io_addr = 0;
        repeat = false;
        may_coe = false;
        res = sg_read_low(sg_fd, bp, blks, lba, bs, ifp, diop, &io_addr);
        switch (res) {
        case 0:
            if (blks_readp)
                *blks_readp = xferred + blks;
            if (coe_limit > 0)
                coe_count = 0;  /* good read clears coe_count */
            return 0;
        case -2:        /* ENOMEM */
            return res;
        case SG_LIB_CAT_NOT_READY:
            pr2serr("Device (r) not ready\n");
            return res;
        case SG_LIB_CAT_ABORTED_COMMAND:
            if (--max_aborted > 0) {
                pr2serr("Aborted command, continuing (r)\n");
                repeat = true;
            } else {
                pr2serr("Aborted command, too many (r)\n");
                return res;
            }
            break;
        case SG_LIB_CAT_UNIT_ATTENTION:
            if (--max_uas > 0) {
                pr2serr("Unit attention, continuing (r)\n");
                repeat = true;
            } else {
                pr2serr("Unit attention, too many (r)\n");
                return res;
            }
            break;
        case SG_LIB_CAT_MEDIUM_HARD_WITH_INFO:
            if (retries_tmp > 0) {
                pr2serr(">>> retrying a sgio read, lba=0x%" PRIx64 "\n",
                        (uint64_t)lba);
                --retries_tmp;
                ++num_retries;
                if (unrecovered_errs > 0)
                    --unrecovered_errs;
                repeat = true;
            }
            ret = SG_LIB_CAT_MEDIUM_HARD;
            break; /* unrecovered read error at lba=io_addr */
        case SG_LIB_SYNTAX_ERROR:
            ifp->coe = 0;
            ret = res;
            goto err_out;
        case -1:
            ret = res;
            goto err_out;
        case SG_LIB_CAT_MEDIUM_HARD:
            may_coe = true;
#if defined(__GNUC__)
#if (__GNUC__ >= 7)
            __attribute__((fallthrough));
            /* FALL THROUGH */
#endif
#endif
        default:
            if (retries_tmp > 0) {
                pr2serr(">>> retrying a sgio read, lba=0x%" PRIx64 "\n",
                        (uint64_t)lba);
                --retries_tmp;
                ++num_retries;
                if (unrecovered_errs > 0)
                    --unrecovered_errs;
                repeat = true;
                break;
            }
            ret = res;
            goto err_out;
        }
        if (repeat)
            continue;
        if ((io_addr < (uint64_t)lba) ||
            (io_addr >= (uint64_t)(lba + blks))) {
                pr2serr("  Unrecovered error lba 0x%" PRIx64 " not in "
                        "correct range:\n\t[0x%" PRIx64 ",0x%" PRIx64 "]\n",
                        io_addr, (uint64_t)lba,
                        (uint64_t)(lba + blks - 1));
            may_coe = true;
            goto err_out;
        }
        blks = (int)(io_addr - (uint64_t)lba);
        if (blks > 0) {
            if (verbose)
                pr2serr("  partial read of %d blocks prior to medium error\n",
                        blks);
            res = sg_read_low(sg_fd, bp, blks, lba, bs, ifp, diop, &io_addr);
            switch (res) {
            case 0:
                break;
            case -1:
                ifp->coe = 0;
                ret = res;
                goto err_out;
            case -2:
                pr2serr("ENOMEM again, unexpected (r)\n");
                return -1;
            case SG_LIB_CAT_NOT_READY:
                pr2serr("device (r) not ready\n");
                return res;
            case SG_LIB_CAT_UNIT_ATTENTION:
                pr2serr("Unit attention, unexpected (r)\n");
                return res;
            case SG_LIB_CAT_ABORTED_COMMAND:
                pr2serr("Aborted command, unexpected (r)\n");
                return res;
            case SG_LIB_CAT_MEDIUM_HARD_WITH_INFO:
            case SG_LIB_CAT_MEDIUM_HARD:
                ret = SG_LIB_CAT_MEDIUM_HARD;
                goto err_out;
            case SG_LIB_SYNTAX_ERROR:
            default:
                pr2serr(">> unexpected result=%d from sg_read_low() 2\n",
                        res);
                ret = res;
                goto err_out;
            }
        }
        xferred += blks;
        if (0 == ifp->coe) {
            /* give up at block before problem unless 'coe' */
            if (blks_readp)
                *blks_readp = xferred;
            return ret;
        }
        if (bs < 32) {
            pr2serr(">> bs=%d too small for read_long\n", bs);
            return -1;  /* nah, block size can't be that small */
        }
        bp += (blks * bs);
        lba += blks;
        if ((0 != ifp->pdt) || (ifp->coe < 2)) {
            pr2serr(">> unrecovered read error at blk=%" PRId64 ", pdt=%d, "
                    "use zeros\n", lba, ifp->pdt);
            memset(bp, 0, bs);
        } else if (io_addr < UINT_MAX) {
            bool corrct, ok;
            int offset, nl, r;
            uint8_t * buffp;
            uint8_t * free_buffp;

            buffp = sg_memalign(bs * 2, 0, &free_buffp, false);
            if (NULL == buffp) {
                pr2serr(">> heap problems\n");
                return -1;
            }
            corrct = (ifp->coe > 2);
            res = sg_ll_read_long10(sg_fd, /* pblock */false, corrct, lba,
                                    buffp, bs + read_long_blk_inc, &offset,
                                    true, verbose);
            ok = false;
            switch (res) {
            case 0:
                ok = true;
                ++read_longs;
                break;
            case SG_LIB_CAT_ILLEGAL_REQ_WITH_INFO:
                nl = bs + read_long_blk_inc - offset;
                if ((nl < 32) || (nl > (bs * 2))) {
                    pr2serr(">> read_long(10) len=%d unexpected\n", nl);
                    break;
                }
                /* remember for next read_long attempt, if required */
                read_long_blk_inc = nl - bs;

                if (verbose)
                    pr2serr("read_long(10): adjusted len=%d\n", nl);
                r = sg_ll_read_long10(sg_fd, false, corrct, lba, buffp, nl,
                                      &offset, true, verbose);
                if (0 == r) {
                    ok = true;
                    ++read_longs;
                    break;
                } else
                    pr2serr(">> unexpected result=%d on second "
                            "read_long(10)\n", r);
                break;
            case SG_LIB_CAT_INVALID_OP:
                pr2serr(">> read_long(10); not supported\n");
                break;
            case SG_LIB_CAT_ILLEGAL_REQ:
                pr2serr(">> read_long(10): bad cdb field\n");
                break;
            case SG_LIB_CAT_NOT_READY:
                pr2serr(">> read_long(10): device not ready\n");
                break;
            case SG_LIB_CAT_UNIT_ATTENTION:
                pr2serr(">> read_long(10): unit attention\n");
                break;
            case SG_LIB_CAT_ABORTED_COMMAND:
                pr2serr(">> read_long(10): aborted command\n");
                break;
            default:
                pr2serr(">> read_long(10): problem (%d)\n", res);
                break;
            }
            if (ok)
                memcpy(bp, buffp, bs);
            else
                memset(bp, 0, bs);
            free(free_buffp);
        } else {
            pr2serr(">> read_long(10) cannot handle blk=%" PRId64 ", use "
                    "zeros\n", lba);
            memset(bp, 0, bs);
        }
        ++xferred;
        bp += bs;
        ++lba;
        if ((coe_limit > 0) && (++coe_count > coe_limit)) {
            if (blks_readp)
                *blks_readp = xferred + blks;
            pr2serr(">> coe_limit on consecutive reads exceeded\n");
            return SG_LIB_CAT_MEDIUM_HARD;
        }
    }
    if (blks_readp)
        *blks_readp = xferred;
    return 0;

err_out:
    if (ifp->coe) {
        memset(bp, 0, bs * blks);
        pr2serr(">> unable to read at blk=%" PRId64 " for %d bytes, use "
                "zeros\n", lba, bs * blks);
        if (blks > 1)
            pr2serr(">>   try reducing bpt to limit number of zeros written "
                    "near bad block(s)\n");
        /* fudge success */
        if (blks_readp)
            *blks_readp = xferred + blks;
        if ((coe_limit > 0) && (++coe_count > coe_limit)) {
            pr2serr(">> coe_limit on consecutive reads exceeded\n");
            return ret;
        }
        return may_coe ? 0 : ret;
    } else
        return ret ? ret : -1;
}


/* 0 -> successful, SG_LIB_SYNTAX_ERROR -> unable to build cdb,
   SG_LIB_CAT_NOT_READY, SG_LIB_CAT_UNIT_ATTENTION, SG_LIB_CAT_MEDIUM_HARD,
   SG_LIB_CAT_ABORTED_COMMAND, -2 -> recoverable (ENOMEM),
   -1 -> unrecoverable error + others */
static int
sg_write(int sg_fd, uint8_t * buff, int blocks, int64_t to_block,
         int bs, const struct flags_t * ofp, bool * diop)
{
    bool info_valid;
    int res, k;
    uint64_t io_addr = 0;
    uint8_t wrCmd[MAX_SCSI_CDBSZ];
    uint8_t senseBuff[SENSE_BUFF_LEN];
    struct sg_io_hdr io_hdr;

    if (sg_build_scsi_cdb(wrCmd, ofp->cdbsz, blocks, to_block, true, ofp->fua,
                          ofp->dpo)) {
        pr2serr(ME "bad wr cdb build, to_block=%" PRId64 ", blocks=%d\n",
                to_block, blocks);
        return SG_LIB_SYNTAX_ERROR;
    }

    memset(&io_hdr, 0, sizeof(struct sg_io_hdr));
    io_hdr.interface_id = 'S';
    io_hdr.cmd_len = ofp->cdbsz;
    io_hdr.cmdp = wrCmd;
    io_hdr.dxfer_direction = SG_DXFER_TO_DEV;
    io_hdr.dxfer_len = bs * blocks;
    io_hdr.dxferp = buff;
    io_hdr.mx_sb_len = SENSE_BUFF_LEN;
    io_hdr.sbp = senseBuff;
    io_hdr.timeout = DEF_TIMEOUT;
    io_hdr.pack_id = (int)to_block;
    if (diop && *diop)
        io_hdr.flags |= SG_FLAG_DIRECT_IO;

    if (verbose > 2) {
        pr2serr("    write cdb: ");
        for (k = 0; k < ofp->cdbsz; ++k)
            pr2serr("%02x ", wrCmd[k]);
        pr2serr("\n");
    }
    while (((res = ioctl(sg_fd, SG_IO, &io_hdr)) < 0) &&
           ((EINTR == errno) || (EAGAIN == errno)))
        ;
    if (res < 0) {
        if (ENOMEM == errno)
            return -2;
        perror("writing (SG_IO) on sg device, error");
        return -1;
    }

    if (verbose > 2)
        pr2serr("      duration=%u ms\n", io_hdr.duration);
    res = sg_err_category3(&io_hdr);
    switch (res) {
    case SG_LIB_CAT_CLEAN:
        break;
    case SG_LIB_CAT_RECOVERED:
        ++recovered_errs;
        info_valid = sg_get_sense_info_fld(io_hdr.sbp, io_hdr.sb_len_wr,
                                           &io_addr);
        if (info_valid) {
            pr2serr("    lba of last recovered error in this WRITE=0x%" PRIx64
                    "\n", io_addr);
            if (verbose > 1)
                sg_chk_n_print3("writing", &io_hdr, true);
        } else {
            pr2serr("Recovered error: [no info] writing to block=0x%" PRIx64
                    ", num=%d\n", to_block, blocks);
            sg_chk_n_print3("writing", &io_hdr, verbose > 1);
        }
        break;
    case SG_LIB_CAT_ABORTED_COMMAND:
    case SG_LIB_CAT_UNIT_ATTENTION:
        sg_chk_n_print3("writing", &io_hdr, verbose > 1);
        return res;
    case SG_LIB_CAT_NOT_READY:
        ++unrecovered_errs;
        pr2serr("device not ready (w)\n");
        return res;
    case SG_LIB_CAT_MEDIUM_HARD:
    default:
        sg_chk_n_print3("writing", &io_hdr, verbose > 1);
        ++unrecovered_errs;
        if (ofp->coe) {
            pr2serr(">> ignored errors for out blk=%" PRId64 " for %d "
                    "bytes\n", to_block, bs * blocks);
            return 0; /* fudge success */
        } else
            return res;
    }
    if (diop && *diop &&
        ((io_hdr.info & SG_INFO_DIRECT_IO_MASK) != SG_INFO_DIRECT_IO))
        *diop = false;      /* flag that dio not done (completely) */
    return 0;
}


static void
calc_duration_throughput(bool contin)
{
    struct timeval end_tm, res_tm;
    double a, b;
    int64_t blks;

    if (start_tm_valid && (start_tm.tv_sec || start_tm.tv_usec)) {
        blks = (in_full > out_full) ? in_full : out_full;
        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 * blks;
        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");
    }
}

/* Process arguments given to 'iflag=" or 'oflag=" options. Returns 0
 * on success, 1 on error. */
static int
process_flags(const char * arg, struct flags_t * fp)
{
    char buff[256];
    char * cp;
    char * np;

    strncpy(buff, arg, sizeof(buff));
    buff[sizeof(buff) - 1] = '\0';
    if ('\0' == buff[0]) {
        pr2serr("no flag found\n");
        return 1;
    }
    cp = buff;
    do {
        np = strchr(cp, ',');
        if (np)
            *np++ = '\0';
        if (0 == strcmp(cp, "append"))
            fp->append = true;
        else if (0 == strcmp(cp, "coe"))
            ++fp->coe;
        else if (0 == strcmp(cp, "dio"))
            fp->dio = true;
        else if (0 == strcmp(cp, "direct"))
            fp->direct = true;
        else if (0 == strcmp(cp, "dpo"))
            fp->dpo = true;
        else if (0 == strcmp(cp, "dsync"))
            fp->dsync = true;
        else if (0 == strcmp(cp, "excl"))
            fp->excl = true;
        else if (0 == strcmp(cp, "flock"))
            fp->flock = true;
        else if (0 == strcmp(cp, "fua"))
            fp->fua = true;
        else if (0 == strcmp(cp, "nocache"))
            ++fp->nocache;
        else if (0 == strcmp(cp, "null"))
            ;
        else if (0 == strcmp(cp, "sgio"))
            fp->sgio = true;
        else if (0 == strcmp(cp, "sparse"))
            fp->sparse = true;
        else {
            pr2serr("unrecognised flag: %s\n", cp);
            return 1;
        }
        cp = np;
    } while (cp);
    return 0;
}

/* Process arguments given to 'conv=" option. Returns 0 on success,
 * 1 on error. */
static int
process_conv(const char * arg, struct flags_t * ifp, struct flags_t * ofp)
{
    char buff[256];
    char * cp;
    char * np;

    strncpy(buff, arg, sizeof(buff));
    buff[sizeof(buff) - 1] = '\0';
    if ('\0' == buff[0]) {
        pr2serr("no conversions found\n");
        return 1;
    }
    cp = buff;
    do {
        np = strchr(cp, ',');
        if (np)
            *np++ = '\0';
#if 0
        if (0 == strcmp(cp, "fdatasync"))
            ++ofp->fdatasync;
        else if (0 == strcmp(cp, "fsync"))
            ++ofp->fsync;
#endif
        if (0 == strcmp(cp, "noerror"))
            ++ifp->coe;         /* will still fail on write error */
        else if (0 == strcmp(cp, "notrunc"))
            ;         /* this is the default action of ddpt so ignore */
        else if (0 == strcmp(cp, "null"))
            ;
#if 0
        else if (0 == strcmp(cp, "sparing"))
            ++ofp->sparing;
#endif
        else if (0 == strcmp(cp, "sparse"))
            ofp->sparse = true;
        else if (0 == strcmp(cp, "sync"))
            ;   /* dd(susv4): pad errored block(s) with zeros but ddpt does
                 * that by default. Typical dd use: 'conv=noerror,sync' */
#if 0
        else if (0 == strcmp(cp, "trunc"))
            ++ofp->trunc;
#endif
        else {
            pr2serr("unrecognised flag: %s\n", cp);
            return 1;
        }
        cp = np;
    } while (cp);
    return 0;
}

/* Returns open input file descriptor (>= 0) or a negative value
 * (-SG_LIB_FILE_ERROR or -SG_LIB_CAT_OTHER) if error.
 */
static int
open_if(const char * inf, int64_t skip, int bpt, struct flags_t * ifp,
        int * in_typep, int vb)
{
    int infd, flags, fl, t, res;
    char ebuff[EBUFF_SZ];
    struct sg_simple_inquiry_resp sir;

    *in_typep = dd_filetype(inf);
    if (vb)
        pr2serr(" >> Input file type: %s\n",
                dd_filetype_str(*in_typep, ebuff));
    if (FT_ERROR & *in_typep) {
        pr2serr(ME "unable access %s\n", inf);
        goto file_err;
    } else if ((FT_BLOCK & *in_typep) && ifp->sgio)
        *in_typep |= FT_SG;

    if (FT_ST & *in_typep) {
        pr2serr(ME "unable to use scsi tape device %s\n", inf);
        goto file_err;
    } else if (FT_SG & *in_typep) {
        flags = O_NONBLOCK;
        if (ifp->direct)
            flags |= O_DIRECT;
        if (ifp->excl)
            flags |= O_EXCL;
        if (ifp->dsync)
            flags |= O_SYNC;
        fl = O_RDWR;
        if ((infd = open(inf, fl | flags)) < 0) {
            fl = O_RDONLY;
            if ((infd = open(inf, fl | flags)) < 0) {
                snprintf(ebuff, EBUFF_SZ,
                         ME "could not open %s for sg reading", inf);
                perror(ebuff);
                goto file_err;
            }
        }
        if (vb)
            pr2serr("        open input(sg_io), flags=0x%x\n", fl | flags);
        if (sg_simple_inquiry(infd, &sir, false, (vb ? (vb - 1) : 0))) {
            pr2serr("INQUIRY failed on %s\n", inf);
            goto other_err;
        }
        ifp->pdt = sir.peripheral_type;
        if (vb)
            pr2serr("    %s: %.8s  %.16s  %.4s  [pdt=%d]\n", inf, sir.vendor,
                    sir.product, sir.revision, ifp->pdt);
        if (! (FT_BLOCK & *in_typep)) {
            t = blk_sz * bpt;
            res = ioctl(infd, SG_SET_RESERVED_SIZE, &t);
            if (res < 0)
                perror(ME "SG_SET_RESERVED_SIZE error");
            res = ioctl(infd, SG_GET_VERSION_NUM, &t);
            if ((res < 0) || (t < 30000)) {
                if (FT_BLOCK & *in_typep)
                    pr2serr(ME "SG_IO unsupported on this block device\n");
                else
                    pr2serr(ME "sg driver prior to 3.x.y\n");
                goto file_err;
            }
        }
    } else {
        flags = O_RDONLY;
        if (ifp->direct)
            flags |= O_DIRECT;
        if (ifp->excl)
            flags |= O_EXCL;
        if (ifp->dsync)
            flags |= O_SYNC;
        infd = open(inf, flags);
        if (infd < 0) {
            snprintf(ebuff, EBUFF_SZ,
                     ME "could not open %s for reading", inf);
            perror(ebuff);
            goto file_err;
        } else {
            if (vb)
                pr2serr("        open input, flags=0x%x\n", flags);
            if (skip > 0) {
                off64_t offset = skip;

                offset *= blk_sz;       /* could exceed 32 bits here! */
                if (lseek64(infd, offset, SEEK_SET) < 0) {
                    snprintf(ebuff, EBUFF_SZ, ME "couldn't skip to "
                             "required position on %s", inf);
                    perror(ebuff);
                    goto file_err;
                }
                if (vb)
                    pr2serr("  >> skip: lseek64 SEEK_SET, byte offset=0x%"
                            PRIx64 "\n", (uint64_t)offset);
            }
#ifdef HAVE_POSIX_FADVISE
            if (ifp->nocache) {
                int rt;

                rt = posix_fadvise(infd, 0, 0, POSIX_FADV_SEQUENTIAL);
                if (rt)
                    pr2serr("open_if: posix_fadvise(SEQUENTIAL), err=%d\n",
                            rt);
            }
#endif
        }
    }
    if (ifp->flock) {
        res = flock(infd, LOCK_EX | LOCK_NB);
        if (res < 0) {
            close(infd);
            snprintf(ebuff, EBUFF_SZ, ME "flock(LOCK_EX | LOCK_NB) on %s "
                     "failed", inf);
            perror(ebuff);
            return -SG_LIB_FLOCK_ERR;
        }
    }
    return infd;

file_err:
    return -SG_LIB_FILE_ERROR;
other_err:
    return -SG_LIB_CAT_OTHER;
}

/* Returns open output file descriptor (>= 0), -1 for don't
 * bother opening (e.g. /dev/null), or a more negative value
 * (-SG_LIB_FILE_ERROR or -SG_LIB_CAT_OTHER) if error.
 */
static int
open_of(const char * outf, int64_t seek, int bpt, struct flags_t * ofp,
        int * out_typep, int vb)
{
    int outfd, flags, t, res;
    char ebuff[EBUFF_SZ];
    struct sg_simple_inquiry_resp sir;

    *out_typep = dd_filetype(outf);
    if (vb)
        pr2serr(" >> Output file type: %s\n",
                dd_filetype_str(*out_typep, ebuff));

    if ((FT_BLOCK & *out_typep) && ofp->sgio)
        *out_typep |= FT_SG;

    if (FT_ST & *out_typep) {
        pr2serr(ME "unable to use scsi tape device %s\n", outf);
        goto file_err;
    } else if (FT_SG & *out_typep) {
        flags = O_RDWR | O_NONBLOCK;
        if (ofp->direct)
            flags |= O_DIRECT;
        if (ofp->excl)
            flags |= O_EXCL;
        if (ofp->dsync)
            flags |= O_SYNC;
        if ((outfd = open(outf, flags)) < 0) {
            snprintf(ebuff, EBUFF_SZ,
                     ME "could not open %s for sg writing", outf);
            perror(ebuff);
            goto file_err;
        }
        if (vb)
            pr2serr("        open output(sg_io), flags=0x%x\n", flags);
        if (sg_simple_inquiry(outfd, &sir, false, (vb ? (vb - 1) : 0))) {
            pr2serr("INQUIRY failed on %s\n", outf);
            goto other_err;
        }
        ofp->pdt = sir.peripheral_type;
        if (vb)
            pr2serr("    %s: %.8s  %.16s  %.4s  [pdt=%d]\n", outf, sir.vendor,
                    sir.product, sir.revision, ofp->pdt);
        if (! (FT_BLOCK & *out_typep)) {
            t = blk_sz * bpt;
            res = ioctl(outfd, SG_SET_RESERVED_SIZE, &t);
            if (res < 0)
                perror(ME "SG_SET_RESERVED_SIZE error");
            res = ioctl(outfd, SG_GET_VERSION_NUM, &t);
            if ((res < 0) || (t < 30000)) {
                pr2serr(ME "sg driver prior to 3.x.y\n");
                goto file_err;
            }
        }
    } else if (FT_DEV_NULL & *out_typep)
        outfd = -1; /* don't bother opening */
    else {
        if (! (FT_RAW & *out_typep)) {
            flags = O_WRONLY | O_CREAT;
            if (ofp->direct)
                flags |= O_DIRECT;
            if (ofp->excl)
                flags |= O_EXCL;
            if (ofp->dsync)
                flags |= O_SYNC;
            if (ofp->append)
                flags |= O_APPEND;
            if ((outfd = open(outf, flags, 0666)) < 0) {
                snprintf(ebuff, EBUFF_SZ,
                        ME "could not open %s for writing", outf);
                perror(ebuff);
                goto file_err;
            }
        } else {
            flags = O_WRONLY;
            if (ofp->direct)
                flags |= O_DIRECT;
            if (ofp->excl)
                flags |= O_EXCL;
            if (ofp->dsync)
                flags |= O_SYNC;
            if ((outfd = open(outf, flags)) < 0) {
                snprintf(ebuff, EBUFF_SZ,
                        ME "could not open %s for raw writing", outf);
                perror(ebuff);
                goto file_err;
            }
        }
        if (vb)
            pr2serr("        %s output, flags=0x%x\n",
                    ((O_CREAT & flags) ? "create" : "open"), flags);
        if (seek > 0) {
            off64_t offset = seek;

            offset *= blk_sz;       /* could exceed 32 bits here! */
            if (lseek64(outfd, offset, SEEK_SET) < 0) {
                snprintf(ebuff, EBUFF_SZ,
                    ME "couldn't seek to required position on %s", outf);
                perror(ebuff);
                goto file_err;
            }
            if (vb)
                pr2serr("   >> seek: lseek64 SEEK_SET, byte offset=0x%" PRIx64
                        "\n", (uint64_t)offset);
        }
    }
    if (ofp->flock) {
        res = flock(outfd, LOCK_EX | LOCK_NB);
        if (res < 0) {
            close(outfd);
            snprintf(ebuff, EBUFF_SZ, ME "flock(LOCK_EX | LOCK_NB) on %s "
                     "failed", outf);
            perror(ebuff);
            return -SG_LIB_FLOCK_ERR;
        }
    }
    return outfd;

file_err:
    return -SG_LIB_FILE_ERROR;
other_err:
    return -SG_LIB_CAT_OTHER;
}

/* Returns the number of times 'ch' is found in string 's' given the
 * string's length. */
static int
num_chs_in_str(const char * s, int slen, int ch)
{
    int res = 0;

    while (--slen >= 0) {
        if (ch == s[slen])
            ++res;
    }
    return res;
}


int
main(int argc, char * argv[])
{
    bool bpt_given = false;
    bool cdbsz_given = false;
    bool dio_tmp, first;
    bool do_sync = false;
    bool penult_sparse_skip = false;
    bool sparse_skip = false;
    bool verbose_given = false;
    bool version_given = false;
    int res, k, n, t, buf_sz, blocks_per, infd, outfd, out2fd, keylen;
    int retries_tmp, blks_read, bytes_read, bytes_of2, bytes_of;
    int in_sect_sz, out_sect_sz;
    int blocks = 0;
    int bpt = DEF_BLOCKS_PER_TRANSFER;
    int dio_incomplete_count = 0;
    int ibs = 0;
    int in_type = FT_OTHER;
    int obs = 0;
    int out_type = FT_OTHER;
    int out2_type = FT_OTHER;
    int penult_blocks = 0;
    int ret = 0;
    int64_t skip = 0;
    int64_t seek = 0;
    int64_t out2_off = 0;
    int64_t in_num_sect = -1;
    int64_t out_num_sect = -1;
    char * key;
    char * buf;
    uint8_t * wrkBuff;
    uint8_t * wrkPos;
    char inf[INOUTF_SZ];
    char outf[INOUTF_SZ];
    char out2f[INOUTF_SZ];
    char str[STR_SZ];
    char ebuff[EBUFF_SZ];

    inf[0] = '\0';
    outf[0] = '\0';
    out2f[0] = '\0';
    iflag.cdbsz = DEF_SCSI_CDBSZ;
    oflag.cdbsz = DEF_SCSI_CDBSZ;

    for (k = 1; k < argc; k++) {
        if (argv[k]) {
            strncpy(str, argv[k], STR_SZ);
            str[STR_SZ - 1] = '\0';
        } else
            continue;
        for (key = str, buf = key; *buf && *buf != '=';)
            buf++;
        if (*buf)
            *buf++ = '\0';
        keylen = strlen(key);
        if (0 == strncmp(key, "app", 3)) {
            iflag.append = !! sg_get_num(buf);
            oflag.append = iflag.append;
        } else if (0 == strcmp(key, "blk_sgio")) {
            iflag.sgio = !! sg_get_num(buf);
            oflag.sgio = iflag.sgio;
        } else if (0 == strcmp(key, "bpt")) {
            bpt = sg_get_num(buf);
            if (-1 == bpt) {
                pr2serr(ME "bad argument to 'bpt='\n");
                return SG_LIB_SYNTAX_ERROR;
            }
            bpt_given = true;
        } else if (0 == strcmp(key, "bs")) {
            blk_sz = sg_get_num(buf);
            bpt_given = true;
        } else if (0 == strcmp(key, "bs")) {
            blk_sz = sg_get_num(buf);
            if (-1 == blk_sz) {
                pr2serr(ME "bad argument to 'bs='\n");
                return SG_LIB_SYNTAX_ERROR;
            }
        } else if (0 == strcmp(key, "cdbsz")) {
            iflag.cdbsz = sg_get_num(buf);
            oflag.cdbsz = iflag.cdbsz;
            cdbsz_given = true;
        } else if (0 == strcmp(key, "coe")) {
            iflag.coe = sg_get_num(buf);
            oflag.coe = iflag.coe;
        } else if (0 == strcmp(key, "coe_limit")) {
            coe_limit = sg_get_num(buf);
            if (-1 == coe_limit) {
                pr2serr(ME "bad argument to 'coe_limit='\n");
                return SG_LIB_SYNTAX_ERROR;
            }
        } else if (0 == strcmp(key, "conv")) {
            if (process_conv(buf, &iflag, &oflag)) {
                pr2serr(ME "bad argument to 'conv='\n");
                return SG_LIB_SYNTAX_ERROR;
            }
        } else if (0 == strcmp(key, "count")) {
            if (0 != strcmp("-1", buf)) {
                dd_count = sg_get_llnum(buf);
                if (-1LL == dd_count) {
                    pr2serr(ME "bad argument to 'count='\n");
                    return SG_LIB_SYNTAX_ERROR;
                }
            }   /* treat 'count=-1' as calculate count (same as not given) */
        } else if (0 == strcmp(key, "dio")) {
            oflag.dio = !! sg_get_num(buf);
            iflag.dio = oflag.dio;
        } else if (0 == strcmp(key, "fua")) {
            t = sg_get_num(buf);
            oflag.fua = !! (t & 1);
            iflag.fua = !! (t & 2);
        } else if (0 == strcmp(key, "ibs"))
            ibs = sg_get_num(buf);
        else if (strcmp(key, "if") == 0) {
            if ('\0' != inf[0]) {
                pr2serr("Second IFILE argument??\n");
                return SG_LIB_SYNTAX_ERROR;
            } else
                strncpy(inf, buf, INOUTF_SZ - 1);
        } else if (0 == strcmp(key, "iflag")) {
            if (process_flags(buf, &iflag)) {
                pr2serr(ME "bad argument to 'iflag='\n");
                return SG_LIB_SYNTAX_ERROR;
            }
        } else if (0 == strcmp(key, "obs"))
            obs = sg_get_num(buf);
        else if (0 == strcmp(key, "odir")) {
            iflag.direct = !! sg_get_num(buf);
            oflag.direct = iflag.direct;
        } else if (strcmp(key, "of") == 0) {
            if ('\0' != outf[0]) {
                pr2serr("Second OFILE argument??\n");
                return SG_LIB_CONTRADICT;
            } else
                strncpy(outf, buf, INOUTF_SZ - 1);
        } else if (strcmp(key, "of2") == 0) {
            if ('\0' != out2f[0]) {
                pr2serr("Second OFILE2 argument??\n");
                return SG_LIB_CONTRADICT;
            } else
                strncpy(out2f, buf, INOUTF_SZ - 1);
        } else if (0 == strcmp(key, "oflag")) {
            if (process_flags(buf, &oflag)) {
                pr2serr(ME "bad argument to 'oflag='\n");
                return SG_LIB_SYNTAX_ERROR;
            }
        } else if (0 == strcmp(key, "retries")) {
            iflag.retries = sg_get_num(buf);
            oflag.retries = iflag.retries;
            if (-1 == iflag.retries) {
                pr2serr(ME "bad argument to 'retries='\n");
                return SG_LIB_SYNTAX_ERROR;
            }
        } else if (0 == strcmp(key, "seek")) {
            seek = sg_get_llnum(buf);
            if (-1LL == seek) {
                pr2serr(ME "bad argument to 'seek='\n");
                return SG_LIB_SYNTAX_ERROR;
            }
        } else if (0 == strcmp(key, "skip")) {
            skip = sg_get_llnum(buf);
            if (-1LL == skip) {
                pr2serr(ME "bad argument to 'skip='\n");
                return SG_LIB_SYNTAX_ERROR;
            }
        } else if (0 == strcmp(key, "sync"))
            do_sync = !! sg_get_num(buf);
        else if (0 == strcmp(key, "time"))
            do_time = !! sg_get_num(buf);
        else if (0 == strncmp(key, "verb", 4))
            verbose = sg_get_num(buf);
        else if ((keylen > 1) && ('-' == key[0]) && ('-' != key[1])) {
            res = 0;
            n = num_chs_in_str(key + 1, keylen - 1, 'd');
            dry_run += n;
            res += n;
            n = num_chs_in_str(key + 1, keylen - 1, 'h');
            if (n > 0) {
                usage();
                return 0;
            }
            n = num_chs_in_str(key + 1, keylen - 1, 'v');
            if (n > 0)
                verbose_given = true;
            verbose += n;
            res += n;
            n = num_chs_in_str(key + 1, keylen - 1, 'V');
            if (n > 0)
                version_given = true;
            res += n;
            if (res < (keylen - 1)) {
                pr2serr("Unrecognised short option in '%s', try '--help'\n",
                        key);
                return SG_LIB_SYNTAX_ERROR;
            }
        } else if ((0 == strncmp(key, "--dry-run", 9)) ||
                 (0 == strncmp(key, "--dry_run", 9)))
            ++dry_run;
        else if ((0 == strncmp(key, "--help", 6)) ||
                 (0 == strcmp(key, "-?"))) {
            usage();
            return 0;
        } else if (0 == strncmp(key, "--verb", 6)) {
            verbose_given = true;
            ++verbose;
        } else if (0 == strncmp(key, "--vers", 6))
            version_given = true;
        else {
            pr2serr("Unrecognized option '%s'\n", key);
            pr2serr("For more information use '--help'\n");
            return SG_LIB_SYNTAX_ERROR;
        }
    }
#ifdef DEBUG
    pr2serr("In DEBUG mode, ");
    if (verbose_given && version_given) {
        pr2serr("but override: '-vV' given, zero verbose and continue\n");
        verbose_given = false;
        version_given = false;
        verbose = 0;
    } else if (! verbose_given) {
        pr2serr("set '-vv'\n");
        verbose = 2;
    } else
        pr2serr("keep verbose=%d\n", verbose);
#else
    if (verbose_given && version_given)
        pr2serr("Not in DEBUG mode, so '-vV' has no special action\n");
#endif
    if (version_given) {
        pr2serr(ME "version: %s\n", version_str);
        return 0;
    }
    if (argc < 2) {
        pr2serr("Won't default both IFILE to stdin _and_ OFILE to stdout\n");
        pr2serr("For more information use '--help'\n");
        return SG_LIB_CONTRADICT;
    }
    if (blk_sz <= 0) {
        blk_sz = DEF_BLOCK_SIZE;
        pr2serr("Assume default 'bs' (block size) of %d bytes\n", blk_sz);
    }
    if ((ibs && (ibs != blk_sz)) || (obs && (obs != blk_sz))) {
        pr2serr("If 'ibs' or 'obs' given must be same as 'bs'\n");
        pr2serr("For more information use '--help'\n");
        return SG_LIB_CONTRADICT;
    }
    if ((skip < 0) || (seek < 0)) {
        pr2serr("skip and seek cannot be negative\n");
        return SG_LIB_CONTRADICT;
    }
    if (oflag.append && (seek > 0)) {
        pr2serr("Can't use both append and seek switches\n");
        return SG_LIB_CONTRADICT;
    }
    if (bpt < 1) {
        pr2serr("bpt must be greater than 0\n");
        return SG_LIB_SYNTAX_ERROR;
    }
    if (iflag.sparse)
        pr2serr("sparse flag ignored for iflag\n");

    /* defaulting transfer size to 128*2048 for CD/DVDs is too large
       for the block layer in lk 2.6 and results in an EIO on the
       SG_IO ioctl. So reduce it in that case. */
    if ((blk_sz >= 2048) && (! bpt_given))
        bpt = DEF_BLOCKS_PER_2048TRANSFER;
#ifdef DEBUG
    pr2serr(ME "if=%s skip=%" PRId64 " of=%s seek=%" PRId64 " count=%" PRId64
            "\n", inf, skip, outf, seek, dd_count);
#endif
    install_handler(SIGINT, interrupt_handler);
    install_handler(SIGQUIT, interrupt_handler);
    install_handler(SIGPIPE, interrupt_handler);
    install_handler(SIGUSR1, siginfo_handler);

    infd = STDIN_FILENO;
    outfd = STDOUT_FILENO;
    iflag.pdt = -1;
    oflag.pdt = -1;
    if (inf[0] && ('-' != inf[0])) {
        infd = open_if(inf, skip, bpt, &iflag, &in_type, verbose);
        if (infd < 0)
            return -infd;
    }

    if (outf[0] && ('-' != outf[0])) {
        outfd = open_of(outf, seek, bpt, &oflag, &out_type, verbose);
        if (outfd < -1)
            return -outfd;
    }

    if (out2f[0]) {
        out2_type = dd_filetype(out2f);
        if ((out2fd = open(out2f, O_WRONLY | O_CREAT, 0666)) < 0) {
            res = errno;
            snprintf(ebuff, EBUFF_SZ,
                     ME "could not open %s for writing", out2f);
            perror(ebuff);
            return res;
        }
    } else
        out2fd = -1;

    if ((STDIN_FILENO == infd) && (STDOUT_FILENO == outfd)) {
        pr2serr("Can't have both 'if' as stdin _and_ 'of' as stdout\n");
        pr2serr("For more information use '--help'\n");
        return SG_LIB_CONTRADICT;
    }
    if (oflag.sparse) {
        if (STDOUT_FILENO == outfd) {
            pr2serr("oflag=sparse needs seekable output file\n");
            return SG_LIB_CONTRADICT;
        }
    }

    if ((dd_count < 0) || ((verbose > 0) && (0 == dd_count))) {
        in_num_sect = -1;
        in_sect_sz = -1;
        if (FT_SG & in_type) {
            res = scsi_read_capacity(infd, &in_num_sect, &in_sect_sz);
            if (SG_LIB_CAT_UNIT_ATTENTION == res) {
                pr2serr("Unit attention (readcap in), continuing\n");
                res = scsi_read_capacity(infd, &in_num_sect, &in_sect_sz);
            } else if (SG_LIB_CAT_ABORTED_COMMAND == res) {
                pr2serr("Aborted command (readcap in), continuing\n");
                res = scsi_read_capacity(infd, &in_num_sect, &in_sect_sz);
            }
            if (0 != res) {
                if (res == SG_LIB_CAT_INVALID_OP)
                    pr2serr("read capacity not supported on %s\n", inf);
                else if (res == SG_LIB_CAT_NOT_READY)
                    pr2serr("read capacity failed on %s - not ready\n", inf);
                else
                    pr2serr("Unable to read capacity on %s\n", inf);
                in_num_sect = -1;
            } else if (in_sect_sz != blk_sz)
                pr2serr(">> warning: block size on %s confusion: bs=%d, "
                        "device claims=%d\n", inf, blk_sz, in_sect_sz);
        } else if (FT_BLOCK & in_type) {
            if (0 != read_blkdev_capacity(infd, &in_num_sect, &in_sect_sz)) {
                pr2serr("Unable to read block capacity on %s\n", inf);
                in_num_sect = -1;
            }
            if (blk_sz != in_sect_sz) {
                pr2serr("block size on %s confusion: bs=%d, device "
                        "claims=%d\n", inf, blk_sz, in_sect_sz);
                in_num_sect = -1;
            }
        }
        if (in_num_sect > skip)
            in_num_sect -= skip;

        out_num_sect = -1;
        out_sect_sz = -1;
        if (FT_SG & out_type) {
            res = scsi_read_capacity(outfd, &out_num_sect, &out_sect_sz);
            if (SG_LIB_CAT_UNIT_ATTENTION == res) {
                pr2serr("Unit attention (readcap out), continuing\n");
                res = scsi_read_capacity(outfd, &out_num_sect, &out_sect_sz);
            } else if (SG_LIB_CAT_ABORTED_COMMAND == res) {
                pr2serr("Aborted command (readcap out), continuing\n");
                res = scsi_read_capacity(outfd, &out_num_sect, &out_sect_sz);
            }
            if (0 != res) {
                if (res == SG_LIB_CAT_INVALID_OP)
                    pr2serr("read capacity not supported on %s\n", outf);
                else
                    pr2serr("Unable to read capacity on %s\n", outf);
                out_num_sect = -1;
            } else if (blk_sz != out_sect_sz)
                pr2serr(">> warning: block size on %s confusion: bs=%d, "
                        "device claims=%d\n", outf, blk_sz, out_sect_sz);
        } else if (FT_BLOCK & out_type) {
            if (0 != read_blkdev_capacity(outfd, &out_num_sect,
                                          &out_sect_sz)) {
                pr2serr("Unable to read block capacity on %s\n", outf);
                out_num_sect = -1;
            } else if (blk_sz != out_sect_sz) {
                pr2serr("block size on %s confusion: bs=%d, device "
                        "claims=%d\n", outf, blk_sz, out_sect_sz);
                out_num_sect = -1;
            }
        }
        if (out_num_sect > seek)
            out_num_sect -= seek;
#ifdef DEBUG
        pr2serr("Start of loop, count=%" PRId64 ", in_num_sect=%" PRId64
                ", out_num_sect=%" PRId64 "\n", dd_count, in_num_sect,
                out_num_sect);
#endif
        if (dd_count < 0) {
            if (in_num_sect > 0) {
                if (out_num_sect > 0)
                    dd_count = (in_num_sect > out_num_sect) ? out_num_sect :
                                                           in_num_sect;
                else
                    dd_count = in_num_sect;
            } else
                dd_count = out_num_sect;
        }
    }

    if (dd_count < 0) {
        pr2serr("Couldn't calculate count, please give one\n");
        return SG_LIB_CAT_OTHER;
    }
    if (! cdbsz_given) {
        if ((FT_SG & in_type) && (MAX_SCSI_CDBSZ != iflag.cdbsz) &&
            (((dd_count + skip) > UINT_MAX) || (bpt > USHRT_MAX))) {
            pr2serr("Note: SCSI command size increased to 16 bytes (for "
                    "'if')\n");
            iflag.cdbsz = MAX_SCSI_CDBSZ;
        }
        if ((FT_SG & out_type) && (MAX_SCSI_CDBSZ != oflag.cdbsz) &&
            (((dd_count + seek) > UINT_MAX) || (bpt > USHRT_MAX))) {
            pr2serr("Note: SCSI command size increased to 16 bytes (for "
                    "'of')\n");
            oflag.cdbsz = MAX_SCSI_CDBSZ;
        }
    }

    if (iflag.dio || iflag.direct || oflag.direct || (FT_RAW & in_type) ||
        (FT_RAW & out_type)) {  /* want heap buffer aligned to page_size */

        wrkPos = sg_memalign(blk_sz * bpt, 0, &wrkBuff, false);
        if (NULL == wrkPos) {
            pr2serr("sg_memalign: error, out of memory?\n");
            return sg_convert_errno(ENOMEM);
        }
    } else {
        wrkPos = sg_memalign(blk_sz * bpt, 0, &wrkBuff, false);
        if (0 == wrkPos) {
            pr2serr("Not enough user memory\n");
            return sg_convert_errno(ENOMEM);
        }
    }

    blocks_per = bpt;
#ifdef DEBUG
    pr2serr("Start of loop, count=%" PRId64 ", blocks_per=%d\n", dd_count,
            blocks_per);
#endif
    if (do_time) {
        start_tm.tv_sec = 0;
        start_tm.tv_usec = 0;
        gettimeofday(&start_tm, NULL);
        start_tm_valid = true;
    }
    req_count = dd_count;

    if (dry_run > 0) {
        pr2serr("Since --dry-run option given, bypassing copy\n");
        goto bypass_copy;
    }

    /* <<< main loop that does the copy >>> */
    while (dd_count > 0) {
        bytes_read = 0;
        bytes_of = 0;
        bytes_of2 = 0;
        penult_sparse_skip = sparse_skip;
        penult_blocks = penult_sparse_skip ? blocks : 0;
        sparse_skip = false;
        blocks = (dd_count > blocks_per) ? blocks_per : dd_count;
        if (FT_SG & in_type) {
            dio_tmp = iflag.dio;
            res = sg_read(infd, wrkPos, blocks, skip, blk_sz, &iflag,
                          &dio_tmp, &blks_read);
            if (-2 == res) {     /* ENOMEM, find what's available+try that */
                if (ioctl(infd, SG_GET_RESERVED_SIZE, &buf_sz) < 0) {
                    perror("RESERVED_SIZE ioctls failed");
                    ret = res;
                    break;
                }
                if (buf_sz < MIN_RESERVED_SIZE)
                    buf_sz = MIN_RESERVED_SIZE;
                blocks_per = (buf_sz + blk_sz - 1) / blk_sz;
                if (blocks_per < blocks) {
                    blocks = blocks_per;
                    pr2serr("Reducing read to %d blocks per loop\n",
                            blocks_per);
                    res = sg_read(infd, wrkPos, blocks, skip, blk_sz,
                                  &iflag, &dio_tmp, &blks_read);
                }
            }
            if (res) {
                pr2serr("sg_read failed,%s at or after lba=%" PRId64 " [0x%"
                        PRIx64 "]\n", ((-2 == res) ?
                                 " try reducing bpt," : ""), skip, skip);
                ret = res;
                break;
            } else {
                if (blks_read < blocks) {
                    dd_count = 0;   /* force exit after write */
                    blocks = blks_read;
                }
                in_full += blocks;
                if (iflag.dio && (! dio_tmp))
                    dio_incomplete_count++;
            }
        } else {
            while (((res = read(infd, wrkPos, blocks * blk_sz)) < 0) &&
                   ((EINTR == errno) || (EAGAIN == errno)))
                ;
            if (verbose > 2)
                pr2serr("read(unix): count=%d, res=%d\n", blocks * blk_sz,
                        res);
            if (res < 0) {
                snprintf(ebuff, EBUFF_SZ, ME "reading, skip=%" PRId64 " ",
                         skip);
                perror(ebuff);
                ret = -1;
                break;
            } else if (res < blocks * blk_sz) {
                dd_count = 0;
                blocks = res / blk_sz;
                if ((res % blk_sz) > 0) {
                    blocks++;
                    in_partial++;
                }
            }
            bytes_read = res;
            in_full += blocks;
        }

        if (0 == blocks)
            break;      /* nothing read so leave loop */

        if (out2f[0]) {
            while (((res = write(out2fd, wrkPos, blocks * blk_sz)) < 0) &&
                   ((EINTR == errno) || (EAGAIN == errno)))
                ;
            if (verbose > 2)
                pr2serr("write to of2: count=%d, res=%d\n", blocks * blk_sz,
                        res);
            if (res < 0) {
                snprintf(ebuff, EBUFF_SZ, ME "writing to of2, seek=%" PRId64
                         " ", seek);
                perror(ebuff);
                ret = -1;
                break;
            }
            bytes_of2 = res;
            out2_off += res;
        }

        if (oflag.sparse && (dd_count > blocks) &&
            (! (FT_DEV_NULL & out_type))) {
            if (NULL == zeros_buff) {
                zeros_buff = sg_memalign(blocks * blk_sz, 0, &free_zeros_buff,
                                         false);
                if (NULL == zeros_buff) {
                    pr2serr("zeros_buff sg_memalign failed\n");
                    ret = -1;
                    break;
                }
            }
            if (0 == memcmp(wrkPos, zeros_buff, blocks * blk_sz))
                sparse_skip = true;
        }
        if (sparse_skip) {
            if (FT_SG & out_type) {
                out_sparse_num += blocks;
                if (verbose > 2)
                    pr2serr("sparse bypassing sg_write: seek blk=%" PRId64
                            ", offset blks=%d\n", seek, blocks);
            } else if (FT_DEV_NULL & out_type)
                ;
            else {
                off64_t offset = blocks * blk_sz;
                off64_t off_res;

                if (verbose > 2)
                    pr2serr("sparse bypassing write: seek=%" PRId64 ", rel "
                            "offset=%" PRId64 "\n", (seek * blk_sz),
                            (int64_t)offset);
                off_res = lseek64(outfd, offset, SEEK_CUR);
                if (off_res < 0) {
                    pr2serr("sparse tried to bypass write: seek=%" PRId64
                            ", rel offset=%" PRId64 " but ...\n",
                            (seek * blk_sz), (int64_t)offset);
                    perror("lseek64 on output");
                    ret = SG_LIB_FILE_ERROR;
                    break;
                } else if (verbose > 4)
                    pr2serr("oflag=sparse lseek64 result=%" PRId64 "\n",
                            (int64_t)off_res);
                out_sparse_num += blocks;
            }
        } else if (FT_SG & out_type) {
            dio_tmp = oflag.dio;
            retries_tmp = oflag.retries;
            first = true;
            while (1) {
                ret = sg_write(outfd, wrkPos, blocks, seek, blk_sz,
                               &oflag, &dio_tmp);
                if (0 == ret)
                    break;
                if ((SG_LIB_CAT_NOT_READY == ret) ||
                    (SG_LIB_SYNTAX_ERROR == ret))
                    break;
                else if ((-2 == ret) && first) {
                    /* ENOMEM: find what's available and try that */
                    if (ioctl(outfd, SG_GET_RESERVED_SIZE, &buf_sz) < 0) {
                        perror("RESERVED_SIZE ioctls failed");
                        break;
                    }
                    if (buf_sz < MIN_RESERVED_SIZE)
                        buf_sz = MIN_RESERVED_SIZE;
                    blocks_per = (buf_sz + blk_sz - 1) / blk_sz;
                    if (blocks_per < blocks) {
                        blocks = blocks_per;
                        pr2serr("Reducing write to %d blocks per loop\n",
                                blocks);
                    } else
                        break;
                } else if ((SG_LIB_CAT_UNIT_ATTENTION == ret) && first) {
                    if (--max_uas > 0)
                        pr2serr("Unit attention, continuing (w)\n");
                    else {
                        pr2serr("Unit attention, too many (w)\n");
                        break;
                    }
                } else if ((SG_LIB_CAT_ABORTED_COMMAND == ret) && first) {
                    if (--max_aborted > 0)
                        pr2serr("Aborted command, continuing (w)\n");
                    else {
                        pr2serr("Aborted command, too many (w)\n");
                        break;
                    }
                } else if (ret < 0)
                    break;
                else if (retries_tmp > 0) {
                    pr2serr(">>> retrying a sgio write, lba=0x%" PRIx64 "\n",
                            (uint64_t)seek);
                    --retries_tmp;
                    ++num_retries;
                    if (unrecovered_errs > 0)
                        --unrecovered_errs;
                } else
                    break;
                first = false;
            }
            if (0 != ret) {
                pr2serr("sg_write failed,%s seek=%" PRId64 "\n",
                        ((-2 == ret) ? " try reducing bpt," : ""), seek);
                break;
            } else {
                out_full += blocks;
                if (oflag.dio && (! dio_tmp))
                    dio_incomplete_count++;
            }
        } else if (FT_DEV_NULL & out_type)
            out_full += blocks; /* act as if written out without error */
        else {
            while (((res = write(outfd, wrkPos, blocks * blk_sz)) < 0) &&
                   ((EINTR == errno) || (EAGAIN == errno)))
                ;
            if (verbose > 2)
                pr2serr("write(unix): count=%d, res=%d\n", blocks * blk_sz,
                        res);
            if (res < 0) {
                snprintf(ebuff, EBUFF_SZ, ME "writing, seek=%" PRId64 " ",
                         seek);
                perror(ebuff);
                ret = -1;
                break;
            } else if (res < blocks * blk_sz) {
                pr2serr("output file probably full, seek=%" PRId64 " ", seek);
                blocks = res / blk_sz;
                out_full += blocks;
                if ((res % blk_sz) > 0)
                    out_partial++;
                ret = -1;
                break;
            } else {
                out_full += blocks;
                bytes_of = res;
            }
        }
#ifdef HAVE_POSIX_FADVISE
        {
            int rt, in_valid, out2_valid, out_valid;

            in_valid = ((FT_OTHER == in_type) || (FT_BLOCK == in_type));
            out2_valid = ((FT_OTHER == out2_type) || (FT_BLOCK == out2_type));
            out_valid = ((FT_OTHER == out_type) || (FT_BLOCK == out_type));
            if (iflag.nocache && (bytes_read > 0) && in_valid) {
                rt = posix_fadvise(infd, 0, (skip * blk_sz) + bytes_read,
                                   POSIX_FADV_DONTNEED);
                // rt = posix_fadvise(infd, (skip * blk_sz), bytes_read,
                                   // POSIX_FADV_DONTNEED);
                // rt = posix_fadvise(infd, 0, 0, POSIX_FADV_DONTNEED);
                if (rt)         /* returns error as result */
                    pr2serr("posix_fadvise on read, skip=%" PRId64
                            " ,err=%d\n", skip, rt);
            }
            if ((oflag.nocache & 2) && (bytes_of2 > 0) && out2_valid) {
                rt = posix_fadvise(out2fd, 0, 0, POSIX_FADV_DONTNEED);
                if (rt)
                    pr2serr("posix_fadvise on of2, seek=%" PRId64
                            " ,err=%d\n", seek, rt);
            }
            if ((oflag.nocache & 1) && (bytes_of > 0) && out_valid) {
                rt = posix_fadvise(outfd, 0, 0, POSIX_FADV_DONTNEED);
                if (rt)
                    pr2serr("posix_fadvise on output, seek=%" PRId64
                            " ,err=%d\n", seek, rt);
            }
        }
#endif
        if (dd_count > 0)
            dd_count -= blocks;
        skip += blocks;
        seek += blocks;
    } /* end of main loop that does the copy ... */

    if (ret && penult_sparse_skip && (penult_blocks > 0)) {
        /* if error and skipped last output due to sparse ... */
        if ((FT_SG & out_type) || (FT_DEV_NULL & out_type))
            ;
        else {
            /* ... try writing to extend ofile to length prior to error */
            while (((res = write(outfd, zeros_buff, penult_blocks * blk_sz))
                    < 0) && ((EINTR == errno) || (EAGAIN == errno)))
                ;
            if (verbose > 2)
                pr2serr("write(unix, sparse after error): count=%d, res=%d\n",
                        penult_blocks * blk_sz, res);
            if (res < 0) {
                snprintf(ebuff, EBUFF_SZ, ME "writing(sparse after error), "
                        "seek=%" PRId64 " ", seek);
                perror(ebuff);
            }
        }
    }

    if (do_sync) {
        if (FT_SG & out_type) {
            pr2serr(">> Synchronizing cache on %s\n", outf);
            res = sg_ll_sync_cache_10(outfd, false, false, 0, 0, 0, true, 0);
            if (SG_LIB_CAT_UNIT_ATTENTION == res) {
                pr2serr("Unit attention (out, sync cache), continuing\n");
                res = sg_ll_sync_cache_10(outfd, false, false, 0, 0, 0,
                                          false, 0);
            }
            if (0 != res)
                pr2serr("Unable to synchronize cache\n");
        }
    }

bypass_copy:
    if (do_time)
        calc_duration_throughput(false);

    free(wrkBuff);
    if (free_zeros_buff)
        free(free_zeros_buff);
    if (STDIN_FILENO != infd)
        close(infd);
    if (! ((STDOUT_FILENO == outfd) || (FT_DEV_NULL & out_type)))
        close(outfd);
    if (dry_run > 0)
        goto bypass2;

    if (0 != dd_count) {
        pr2serr("Some error occurred,");
        if (0 == ret)
            ret = SG_LIB_CAT_OTHER;
    }
    print_stats("");
    if (dio_incomplete_count) {
        int fd;
        char c;

        pr2serr(">> Direct IO requested but incomplete %d times\n",
                dio_incomplete_count);
        if ((fd = open(proc_allow_dio, O_RDONLY)) >= 0) {
            if (1 == read(fd, &c, 1)) {
                if ('0' == c)
                    pr2serr(">>> %s set to '0' but should be set to '1' for "
                            "direct IO\n", proc_allow_dio);
            }
            close(fd);
        }
    }
    if (sum_of_resids)
        pr2serr(">> Non-zero sum of residual counts=%d\n", sum_of_resids);

bypass2:
    return (ret >= 0) ? ret : SG_LIB_CAT_OTHER;
}
