dcfldd/dcfldd.c

/* $Id: dcfldd.c,v 1.7 2005/06/15 14:33:04 harbourn Exp $
 * dcfldd - The Enhanced Forensic DD
 * By Nicholas Harbour
 */
/* Copyright (C) 85, 90, 91, 1995-2001, 2005 Free Software Foundation, Inc.
   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 distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software Foundation,
   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

/* GNU dd originally written by Paul Rubin, David MacKenzie, and Stuart Kemp. */

#include "dcfldd.h"

/*
 *
 * How bored are you? sitting around reading source code, its sad.
 *
 */

#include "config.h"
#include <string.h>
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>

#if HAVE_INTTYPES_H
# include <inttypes.h>
#endif
#include <sys/types.h>
#include <sys/stat.h>
#include <dirent.h>
#include <ctype.h>
#include <signal.h>
#include <getopt.h>
#include <time.h>
#include <fcntl.h>
#include "system.h"
#include "human.h"
#include "long-options.h"
#include "safe-read.h"
#include "xstrtol.h"
#include "full-write.h"
#include "copy.h"
#include "hash.h"
#include "verify.h"
#include "translate.h"
#include "sizeprobe.h"
#include "pattern.h"
#include "output.h"
#include "split.h"
#include "hashformat.h"
#include "util.h"
#include "log.h"

/* The name this program was run with. */
char *program_name;

/* The name of the input file, or NULL for the standard input. */
char *input_file = NULL;

/* The name of the output file, or NULL for the standard output. */
char *output_file = NULL;

/* The number of bytes in which atomic reads are done. */
size_t input_blocksize = 0;

/* The number of bytes in which atomic writes are done. */
size_t output_blocksize = 0;

/* Conversion buffer size, in bytes.  0 prevents conversions. */
size_t conversion_blocksize = 0;

/* Skip this many records of `input_blocksize' bytes before input. */
uintmax_t skip_records = 0;

/* Skip this many records of `output_blocksize' bytes before output. */
uintmax_t seek_records = 0;

/* Copy only this many records.  The default is effectively infinity.  */
uintmax_t max_records = (uintmax_t) -1;

/* Bit vector of conversions to apply. */
int conversions_mask = 0;

/* Number of partial blocks written. */
uintmax_t w_partial = 0;

/* Number of full blocks written. */
uintmax_t w_full = 0;

/* Number of partial blocks read. */
uintmax_t r_partial = 0;

/* Number of full blocks read. */
uintmax_t r_full = 0;

/* If nonzero, filter characters through the translation table.  */
int translation_needed = 0;

/* Records truncated by conv=block. */
uintmax_t r_truncate = 0;

/* If nonnzero, the last char from the previous call to `swab_buffer'
   is saved in `saved_char'.  */
int char_is_saved = 0;

/* Odd char from previous call.  */
unsigned char saved_char;

int do_status = 1;
int do_hash = 0;
int do_verify = 0;
int do_split = 0;

hashconv_t hashconv = DEFAULT_HASHCONV;

static char *splitformat = DEFAULT_SPLIT_FORMAT;
static off_t splitsize;

/* How many blocks in between screen writes for status output. */
ssize_t update_thresh = 256;

time_t start_time;

static struct conversion conversions[] =
{
    {"ascii", C_ASCII | C_TWOBUFS},	/* EBCDIC to ASCII. */
    {"ebcdic", C_EBCDIC | C_TWOBUFS},	/* ASCII to EBCDIC. */
    {"ibm", C_IBM | C_TWOBUFS},	/* Slightly different ASCII to EBCDIC. */
    {"block", C_BLOCK | C_TWOBUFS},	/* Variable to fixed length records. */
    {"unblock", C_UNBLOCK | C_TWOBUFS},	/* Fixed to variable length records. */
    {"lcase", C_LCASE | C_TWOBUFS},	/* Translate upper to lower case. */
    {"ucase", C_UCASE | C_TWOBUFS},	/* Translate lower to upper case. */
    {"swab", C_SWAB | C_TWOBUFS},	/* Swap bytes of input. */
    {"noerror", C_NOERROR},	/* Ignore i/o errors. */
    {"notrunc", C_NOTRUNC},	/* Do not truncate output file. */
    {"sync", C_SYNC},		/* Pad input records to ibs with NULs. */
    {NULL, 0}
};

void usage(int status)
{
    if (status != 0)
        log_info("Try `%s --help' for more information.\n", program_name);
    else {
        printf("Usage: %s [OPTION]...\n", program_name);
        printf("\
Copy a file, converting and formatting according to the options.\n\
\n\
  bs=BYTES                 force ibs=BYTES and obs=BYTES\n\
  cbs=BYTES                convert BYTES bytes at a time\n\
  conv=KEYWORDS            convert the file as per the comma separated keyword list\n\
  count=BLOCKS             copy only BLOCKS input blocks\n\
  ibs=BYTES                read BYTES bytes at a time\n\
  if=FILE                  read from FILE instead of stdin\n\
  obs=BYTES                write BYTES bytes at a time\n\
  of=FILE                  write to FILE instead of stdout\n\
                            NOTE: of=FILE may be used several times to write\n\
                                  output to multiple files simultaneously\n\
  of:=COMMAND              exec and write output to process COMMAND\n\
  seek=BLOCKS              skip BLOCKS obs-sized blocks at start of output\n\
  skip=BLOCKS              skip BLOCKS ibs-sized blocks at start of input\n\
  pattern=HEX              use the specified binary pattern as input\n\
  textpattern=TEXT         use repeating TEXT as input\n\
  errlog=FILE              send error messages to FILE as well as stderr\n\
  hashwindow=BYTES         perform a hash on every BYTES amount of data\n\
  hash=NAME                either md5, sha1, sha256, sha384 or sha512\n\
                             default algorithm is md5. To select multiple\n\
                             algorithms to run simultaneously enter the names\n\
                             in a comma separated list\n\
  hashlog=FILE             send MD5 hash output to FILE instead of stderr\n\
                             if you are using multiple hash algorithms you\n\
                             can send each to a separate file using the\n\
                             convention ALGORITHMlog=FILE, for example\n\
                             md5log=FILE1, sha1log=FILE2, etc.\n\
  hashlog:=COMMAND         exec and write hashlog to process COMMAND\n\
                             ALGORITHMlog:=COMMAND also works in the same fashion\n\
  hashconv=[before|after]  perform the hashing before or after the conversions\n\
  hashformat=FORMAT        display each hashwindow according to FORMAT\n\
                             the hash format mini-language is described below\n\
  totalhashformat=FORMAT   display the total hash value according to FORMAT\n\
  status=[on|off]          display a continual status message on stderr\n\
                             default state is \"on\"\n\
  statusinterval=N         update the status message every N blocks\n\
                             default value is 256\n\
  sizeprobe=[if|of]        determine the size of the input or output file\n\
                             for use with status messages. (this option\n\
                             gives you a percentage indicator)\n\
                             WARNING: do not use this option against a\n\
                                      tape device.\n\
  split=BYTES              write every BYTES amount of data to a new file\n\
                             This operation applies to any of=FILE that follows\n\
  splitformat=TEXT         the file extension format for split operation.\n\
                             you may use any number of 'a' or 'n' in any combo\n\
                             the default format is \"nnn\"\n\
                             NOTE: The split and splitformat options take effect\n\
                                  only for output files specified AFTER these\n\
                                  options appear in the command line.  Likewise,\n\
                                  you may specify these several times for\n\
                                  for different output files within the same\n\
                                  command line. you may use as many digits in\n\
                                  any combination you would like.\n\
                                  (e.g. \"anaannnaana\" would be valid, but\n\
                                  quite insane)\n\
  vf=FILE                  verify that FILE matches the specified input\n\
  verifylog=FILE           send verify results to FILE instead of stderr\n\
  verifylog:=COMMAND       exec and write verify results to process COMMAND\n\
\n\
    --help           display this help and exit\n\
    --version        output version information and exit\n\
\n\
The structure of of FORMAT may contain any valid text and special variables.\n\
The built-in variables are used the following format: #variable_name#\n\
To pass FORMAT strings to the program from a command line, it may be\n\
necessary to surround your FORMAT strings with \"quotes.\"\n\
The built-in variables are listed below:\n\
\n\
  window_start    The beginning byte offset of the hashwindow\n\
  window_end      The ending byte offset of the hashwindow\n\
  block_start     The beginning block (by input blocksize) of the window\n\
  block_end       The ending block (by input blocksize) of the hash window\n\
  hash            The hash value\n\
  algorithm       The name of the hash algorithm\n\
\n\
For example, the default FORMAT for hashformat and totalhashformat are:\n\
   hashformat=\"#window_start# - #window_end#: #hash#\"\n\
   totalhashformat=\"Total (#algorithm#): #hash#\"\n\
\n\
The FORMAT structure accepts the following escape codes:\n\
  \\n   Newline\n\
  \\t   Tab\n\
  \\r   Carriage return\n\
  \\\\   Insert the '\\' character\n\
  ##   Insert the '#' character as text, not a variable\n\
\n\
BLOCKS and BYTES may be followed by the following multiplicative suffixes:\n\
xM M, c 1, w 2, b 512, kD 1000, k 1024, MD 1,000,000, M 1,048,576,\n\
GD 1,000,000,000, G 1,073,741,824, and so on for T, P, E, Z, Y.\n\
Each KEYWORD may be:\n\
\n\
  ascii     from EBCDIC to ASCII\n\
  ebcdic    from ASCII to EBCDIC\n\
  ibm       from ASCII to alternated EBCDIC\n\
  block     pad newline-terminated records with spaces to cbs-size\n\
  unblock   replace trailing spaces in cbs-size records with newline\n\
  lcase     change upper case to lower case\n\
  notrunc   do not truncate the output file\n\
  ucase     change lower case to upper case\n\
  swab      swap every pair of input bytes\n\
  noerror   continue after read errors\n\
  sync      pad every input block with NULs to ibs-size; when used\n\
            with block or unblock, pad with spaces rather than NULs\n\
");
        puts("\nReport bugs to <nicholasharbour@yahoo.com>.");
    }
    exit(status);
}

void print_stats(void)
{
    char buf[2][LONGEST_HUMAN_READABLE + 1];
    log_info("%s+%s records in\n",
            human_readable (r_full, buf[0], 1, 1),
            human_readable (r_partial, buf[1], 1, 1));
    log_info("%s+%s records out\n",
            human_readable (w_full, buf[0], 1, 1),
            human_readable (w_partial, buf[1], 1, 1));
    if (r_truncate > 0) {
        log_info("%s %s\n",
                human_readable (r_truncate, buf[0], 1, 1),
                (r_truncate == 1
                 ? "truncated record"
                 : "truncated records"));
    }
}

void cleanup(void)
{
    if (do_status)
        fprintf(stderr, "\n");
    if (!do_verify)
        print_stats();
    if (close(STDIN_FILENO) < 0)
        ;
    if (close(STDOUT_FILENO) < 0)
        ;
}

inline void quit(int code)
{
    cleanup();
    exit(code);
}

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

    sigact.sa_handler = SIG_DFL;
    sigemptyset(&sigact.sa_mask);
    sigact.sa_flags = 0;
    sigaction(sig, &sigact, NULL);
#else
    signal(sig, SIG_DFL);
#endif
    cleanup();
    kill(getpid(), sig);
}

static void siginfo_handler(int sig)
{
    print_stats();
}

/* Encapsulate portability mess of establishing signal handlers.  */

static void install_handler(int sig_num, void (*sig_handler) (int sig))
{
#ifdef SA_NOCLDSTOP
    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);
    }
#else
    if (signal(sig_num, SIG_IGN) != SIG_IGN)
        signal(sig_num, sig_handler);
#endif
}

/* Open a file to a particular file descriptor.  This is like standard
   `open', except it always returns DESIRED_FD if successful.  */
static int open_fd(int desired_fd, char const *filename,
                   int options, mode_t mode)
{
    int fd;
    close(desired_fd);
    fd = open(filename, options, mode);
    if (fd < 0)
        return -1;
    
    if (fd != desired_fd) {
        if (dup2(fd, desired_fd) != desired_fd)
            desired_fd = -1;
        if (close(fd) != 0)
            return -1;
    }
    
    return desired_fd;
}

/* Interpret one "conv=..." option.
 * As a by product, this function replaces each `,' in STR with a NUL byte.
 */
void parse_conversion(char *str)
{
    char *new;
    unsigned int i;
    
    do {
        new = strchr(str, ',');
        if (new != NULL)
            *new++ = '\0';
        for (i = 0; conversions[i].convname != NULL; i++)
            if (STREQ(conversions[i].convname, str)) {
                conversions_mask |= conversions[i].conversion;
                break;
            }
        if (conversions[i].convname == NULL) {
            log_info("invalid conversion: %s\n", str);
            usage(1);
        }
        str = new;
    } while (new != NULL);
}

void parse_hash(char *str)
{
    char *new;
    unsigned int i;

    do {
        new = strchr(str, ',');
        if (new != NULL)
            *new++ = '\0';
        for (i = 0; hashops[i].name != NULL; i++)
            if (STREQ(hashops[i].name, str)) {
                hashflags |= hashops[i].flag;
                break;
            }
        if (hashops[i].name == NULL) {
            log_info("invalid hash: %s\n", str);
            usage(1);
        }
        str = new;
    } while (new != NULL);
}

/* Return the value of STR, interpreted as a non-negative decimal integer,
 * optionally multiplied by various values.
 * Assign nonzero to *INVALID if STR does not represent a number in
 * this format.
 */

#if HAVE_DECL_STRTOUMAX
#  define __strtol_t uintmax_t
#  define __strtol xstrtoumax
#elif HAVE_DECL_STRTOUL
#  define __strtol_t unsigned long int
#  define __strtol xstrtoul
#else
#  define __strtol_t long int
#  define __strtol xstrtol
#endif

__strtol_t parse_integer(const char *str, int *invalid)
{
    __strtol_t n;
    char *suffix;
    enum strtol_error e = __strtol(str, &suffix, 10, &n, "bcEGkMPTwYZ0");
    
    if (e == LONGINT_INVALID_SUFFIX_CHAR && *suffix == 'x') {
        __strtol_t multiplier = parse_integer(suffix + 1, invalid);
        
        if (multiplier != 0 && n * multiplier / multiplier != n) {
            *invalid = 1;
            return 0;
        }
        
        n *= multiplier;
    }
    else if (e != LONGINT_OK) {
        *invalid = 1;
        return 0;
    }
    
    return n;
}

int hex2char(char *hstr)
{
    int retval;
    
    if (strlen(hstr) != 2)
        return -1;
    if (EOF == sscanf(hstr, "%x", &retval))
        return -1;
    return retval;
}

static void scanargs(int argc, char **argv)
{
    int i;
    
    --argc;
    ++argv;
    
    for (i = optind; i < argc; i++) {
        char *name, *val;

        name = argv[i];
        val = strchr(name, '=');
        if (val == NULL) {
            log_info("%s: unrecognized option %s\n", program_name, name);
            usage(1);
        }
        *val++ = '\0';
        
        if (STREQ(name, "if")) 
            if (STREQ(val, "/dev/zero")) { /* replace if=/dev/zero with pattern=00 */
                pattern = make_pattern("00");
                pattern_len = 1;
                input_from_pattern = 1;
            } else
                input_file = val;
        else if (STREQ(name, "of"))
            if (do_split)
                outputlist_add(SPLIT_FILE, val, splitformat, splitsize);
            else
                open_output(val);
        else if (STREQ(name, "of:"))
            open_output_pipe(val);
        else if (STREQ(name, "vf")) {
            verify_file = val;
            do_verify++;
        } else if (STREQ(name, "conv"))
            parse_conversion(val);
        else if (STREQ(name, "pattern")) {
            pattern = make_pattern(val);
            if (pattern == NULL) {
                log_info("%s: invalid hex pattern: %s", program_name, val);
                quit(1);
            }
            input_from_pattern = 1;
        } else if (STREQ(name, "textpattern")) {
            pattern = val;
            pattern_len = strlen(pattern);
            input_from_pattern = 1;
        } else if (STREQ(name, "hashlog")) {
            hash_log = fopen(val, "w");
            if (hash_log == NULL)
                syscall_error(val);
            do_hash++;
        } else if (STREQ(name, "hashlog:")) {
            hash_log = popen2(val, "w");
            if (hash_log == NULL)
                syscall_error(val);
            do_hash++;
        } else if (STREQ(name, "hashformat"))
            hashformat = parse_hashformat(val);
        else if (STREQ(name, "totalhashformat"))
            totalhashformat = parse_hashformat(val);
        else if (STREQ(name, "md5log")) {
            hashops[MD5].log = fopen(val, "w");
            if (hashops[MD5].log == NULL)
                syscall_error(val);
            do_hash++;
        } else if (STREQ(name, "md5log:")) {
            hashops[MD5].log = popen2(val, "w");
            if (hashops[MD5].log == NULL)
                syscall_error(val);
            do_hash++;
        } else if (STREQ(name, "sha1log")) {
            hashops[SHA1].log = fopen(val, "w");
            if (hashops[SHA1].log == NULL)
                syscall_error(val);
            do_hash++;
        } else if (STREQ(name, "sha1log:")) {
            hashops[SHA1].log = popen2(val, "w");
            if (hashops[SHA1].log == NULL)
                syscall_error(val);
            do_hash++;
        } else if (STREQ(name, "sha256log")) {
            hashops[SHA256].log = fopen(val, "w");
            if (hashops[SHA256].log == NULL)
                syscall_error(val);
            do_hash++;
        } else if (STREQ(name, "sha256log:")) {
            hashops[SHA256].log = popen2(val, "w");
            if (hashops[SHA256].log == NULL)
                syscall_error(val);
            do_hash++;
        } else if (STREQ(name, "sha384log")) {
            hashops[SHA384].log = fopen(val, "w");
            if (hashops[SHA384].log == NULL)
                syscall_error(val);
            do_hash++;
        } else if (STREQ(name, "sha384log:")) {
            hashops[SHA384].log = popen2(val, "w");
            if (hashops[SHA384].log == NULL)
                syscall_error(val);
            do_hash++;
        } else if (STREQ(name, "sha512log")) {
            hashops[SHA512].log = fopen(val, "w");
            if (hashops[SHA512].log == NULL)
                syscall_error(val);
            do_hash++;
        } else if (STREQ(name, "sha512log:")) {
            hashops[SHA512].log = popen2(val, "w");
            if (hashops[SHA512].log == NULL)
                syscall_error(val);
            do_hash++;
        } else if (STREQ(name, "verifylog")) {
            verify_log = fopen(val, "w");
            if (verify_log == NULL)
                syscall_error(val);
        } else if (STREQ(name, "verifylog:")) {
            verify_log = popen2(val, "w");
            if (verify_log == NULL)
                syscall_error(val);
        } else if (STREQ(name, "errlog")) {
            errlog = fopen(val, "w");
            if (errlog == NULL)
                syscall_error(val);
        } else if (STREQ(name, "errlog:")) {
            errlog = popen2(val, "w");
            if (errlog == NULL)
                syscall_error(val);
        } else if (STREQ(name, "splitformat"))
            splitformat = val;
        else if (STREQ(name, "status")) {
            if (STREQ(val, "off"))
                do_status = 0;
            else if (STREQ(val, "on")) 
                do_status = 1;
        } else if (STREQ(name, "hashalgorithm") || STREQ(name, "hash")) {
            parse_hash(val);
            do_hash++;
        } else if (STREQ(name, "hashconv"))
            if (STREQ(val, "before"))
                hashconv = HASHCONV_BEFORE;
            else if (STREQ(val, "after"))
                hashconv = HASHCONV_AFTER;
            else
                user_error("invalid hashconv value \"%s\"", val);
        else if (STREQ(name, "sizeprobe")) {
            if (STREQ(val, "if"))
                probe = PROBE_INPUT;
            else if (STREQ(val, "of"))
                probe = PROBE_OUTPUT;
            else 
                probe = PROBE_NONE;
        } else {
            int invalid = 0;
            uintmax_t n = parse_integer(val, &invalid);
            
            if (STREQ(name, "ibs")) {
                input_blocksize = n;
                invalid |= input_blocksize != n || input_blocksize == 0;
                conversions_mask |= C_TWOBUFS;
            }
            else if (STREQ(name, "obs")) {
                output_blocksize = n;
                invalid |= output_blocksize != n || output_blocksize == 0;
                conversions_mask |= C_TWOBUFS;
            } else if (STREQ(name, "bs")) {
                output_blocksize = input_blocksize = n;
                invalid |= output_blocksize != n || output_blocksize == 0;
            } else if (STREQ(name, "cbs")) {
                conversion_blocksize = n;
                invalid |= (conversion_blocksize != n
                            || conversion_blocksize == 0);
            } else if (STREQ(name, "skip"))
                skip_records = n;
            else if (STREQ(name, "vskip"))
                vskip_records = n;
            else if (STREQ(name, "seek"))
                seek_records = n;
            else if (STREQ(name, "count"))
                max_records = n;
            else if (STREQ(name, "split")) {
                splitsize = n;
                do_split++;
            } else if (STREQ(name, "hashwindow")) {
                hash_windowlen = n;
                do_hash++;
            } else if (STREQ(name, "statusinterval")) {
                update_thresh = n;
            } else {
                log_info("%s: unrecognized option %s=%s",
                        program_name, name, val);
                usage(1);
            }
            
            if (invalid)
                log_info("%s: invalid number %s", program_name, val);
        }
    }
    
/* If bs= was given, both `input_blocksize' and `output_blocksize' will
   have been set to positive values.  If either has not been set,
   bs= was not given, so make sure two buffers are used. */
    if (input_blocksize == 0 || output_blocksize == 0)
        conversions_mask |= C_TWOBUFS;
    if (input_blocksize == 0)
        input_blocksize = DEFAULT_BLOCKSIZE;
    if (output_blocksize == 0)
        output_blocksize = DEFAULT_BLOCKSIZE;
    if (conversion_blocksize == 0)
        conversions_mask &= ~(C_BLOCK | C_UNBLOCK);

    /* set all unset hashlogs to go to the overall hashlog */
    for (i = 0; hashops[i].name != NULL; i++)
        if (hashops[i].log == NULL)
            hashops[i].log = hash_log;

    if (do_hash && hashflags == 0)
        hashflags = hashops[DEFAULT_HASH].flag;
    
    if (do_verify) {
        do_hash = 0;
        init_hashlist(&ihashlist, hashops[VERIFY_HASH].flag);
    } else if (do_hash) 
        init_hashlist(&ihashlist, hashflags);

    /* make sure selected options make sense */
    if (output_file != NULL && verify_file != NULL)
        user_error("Please select either an output file or a verify file, not both.");
}


int main(int argc, char **argv)
{
    int i;
    int exit_status;
    char *def_hashwin_fmt;
    char *def_totalhash_fmt;

    def_hashwin_fmt = strndup(DEFAULT_HASHWINDOW_FORMAT,
                              strlen(DEFAULT_HASHWINDOW_FORMAT));
    def_totalhash_fmt = strndup(DEFAULT_TOTALHASH_FORMAT,
                                strlen(DEFAULT_TOTALHASH_FORMAT));
    
    /* disable buffering on stderr */
    setbuf(stderr, NULL);
    
    hash_log = stderr;
    verify_log = stderr;
    
    program_name = argv[0];

    hashformat = parse_hashformat(def_hashwin_fmt);
    totalhashformat = parse_hashformat(def_totalhash_fmt);
    
    /* Arrange to close stdout if parse_long_options exits.  */
    //atexit (close_stdout_wrapper);
    
    parse_long_options(argc, argv, PROGRAM_NAME, PACKAGE, VERSION,
                        AUTHORS, usage);
    
    /* Don't close stdout on exit from here on.  */
    //closeout_func = NULL;
    
    /* Initialize translation table to identity translation. */
    for (i = 0; i < 256; i++)
        trans_table[i] = i;
    
    /* Decode arguments. */
    scanargs(argc, argv);
    
    apply_translations();
    
    if (input_file != NULL) {
        if (open_fd(STDIN_FILENO, input_file, O_RDONLY, 0) < 0)
            syscall_error(input_file);
    } else if (pattern == NULL)
        input_file = "standard input";

    if (verify_file != NULL)
        if ((verify_fd = open(verify_file, O_RDONLY)) < 0)
            syscall_error(verify_file);
    
    if (outputlist == NULL)
        outputlist_add(SINGLE_FILE, STDOUT_FILENO);
    
    install_handler(SIGINT, interrupt_handler);
    install_handler(SIGQUIT, interrupt_handler);
    install_handler(SIGPIPE, interrupt_handler);
    install_handler(SIGINFO, siginfo_handler);
    
    if (probe == PROBE_INPUT)
        if (input_from_pattern)
            probe = PROBE_NONE;
        else
            sizeprobe(STDIN_FILENO);
    else if (probe == PROBE_OUTPUT)
        sizeprobe(STDOUT_FILENO);
    start_time = time(NULL);
    
    if (do_verify)
        exit_status = dd_verify();
    else
        exit_status = dd_copy();

    close(1);
    quit(exit_status);
}