coreutils/dd.c - busybox - Git at Google

 /* vi: set sw=4 ts=4: */
 /*
  * Mini dd implementation for busybox
  *
  *
  * Copyright (C) 2000,2001  Matt Kraai
  *
  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */

 //usage:#define dd_trivial_usage
 //usage:       "[if=FILE] [of=FILE] " IF_FEATURE_DD_IBS_OBS("[ibs=N] [obs=N] ") "[bs=N] [count=N] [skip=N]\n"
 //usage:       "	[seek=N]" IF_FEATURE_DD_IBS_OBS(" [conv=notrunc|noerror|sync|fsync]")
 //usage:#define dd_full_usage "\n\n"
 //usage:       "Copy a file with converting and formatting\n"
 //usage:     "\n	if=FILE		Read from FILE instead of stdin"
 //usage:     "\n	of=FILE		Write to FILE instead of stdout"
 //usage:     "\n	bs=N		Read and write N bytes at a time"
 //usage:	IF_FEATURE_DD_IBS_OBS(
 //usage:     "\n	ibs=N		Read N bytes at a time"
 //usage:	)
 //usage:	IF_FEATURE_DD_IBS_OBS(
 //usage:     "\n	obs=N		Write N bytes at a time"
 //usage:	)
 //usage:     "\n	count=N		Copy only N input blocks"
 //usage:     "\n	skip=N		Skip N input blocks"
 //usage:     "\n	seek=N		Skip N output blocks"
 //usage:	IF_FEATURE_DD_IBS_OBS(
 //usage:     "\n	conv=notrunc	Don't truncate output file"
 //usage:     "\n	conv=noerror	Continue after read errors"
 //usage:     "\n	conv=sync	Pad blocks with zeros"
 //usage:     "\n	conv=fsync	Physically write data out before finishing"
 //usage:     "\n	conv=swab	Swap every pair of bytes"
 //usage:	)
 //usage:     "\n"
 //usage:     "\nN may be suffixed by c (1), w (2), b (512), kD (1000), k (1024), MD, M, GD, G"
 //usage:
 //usage:#define dd_example_usage
 //usage:       "$ dd if=/dev/zero of=/dev/ram1 bs=1M count=4\n"
 //usage:       "4+0 records in\n"
 //usage:       "4+0 records out\n"

 #include "libbb.h"

 /* This is a NOEXEC applet. Be very careful! */


 enum {
 	ifd = STDIN_FILENO,
 	ofd = STDOUT_FILENO,
 };

 static const struct suffix_mult dd_suffixes[] = {
 	{ "c", 1 },
 	{ "w", 2 },
 	{ "b", 512 },
 	{ "kD", 1000 },
 	{ "k", 1024 },
 	{ "K", 1024 },  /* compat with coreutils dd */
 	{ "MD", 1000000 },
 	{ "M", 1048576 },
 	{ "GD", 1000000000 },
 	{ "G", 1073741824 },
 	{ "", 0 }
 };

 struct globals {
 	off_t out_full, out_part, in_full, in_part;
 #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
 	unsigned long long total_bytes;
 	unsigned long long begin_time_us;
 #endif
 } FIX_ALIASING;
 #define G (*(struct globals*)&bb_common_bufsiz1)
 #define INIT_G() do { \
 	/* we have to zero it out because of NOEXEC */ \
 	memset(&G, 0, sizeof(G)); \
 } while (0)


 static void dd_output_status(int UNUSED_PARAM cur_signal)
 {
 #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
 	double seconds;
 	unsigned long long bytes_sec;
 	unsigned long long now_us = monotonic_us(); /* before fprintf */
 #endif

 	/* Deliberately using %u, not %d */
 	fprintf(stderr, "%"OFF_FMT"u+%"OFF_FMT"u records in\n"
 			"%"OFF_FMT"u+%"OFF_FMT"u records out\n",
 			G.in_full, G.in_part,
 			G.out_full, G.out_part);

 #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
 	fprintf(stderr, "%llu bytes (%sB) copied, ",
 			G.total_bytes,
 			/* show fractional digit, use suffixes */
 			make_human_readable_str(G.total_bytes, 1, 0)
 	);
 	/* Corner cases:
 	 * ./busybox dd </dev/null >/dev/null
 	 * ./busybox dd bs=1M count=2000 </dev/zero >/dev/null
 	 * (echo DONE) | ./busybox dd >/dev/null
 	 * (sleep 1; echo DONE) | ./busybox dd >/dev/null
 	 */
 	seconds = (now_us - G.begin_time_us) / 1000000.0;
 	bytes_sec = G.total_bytes / seconds;
 	fprintf(stderr, "%f seconds, %sB/s\n",
 			seconds,
 			/* show fractional digit, use suffixes */
 			make_human_readable_str(bytes_sec, 1, 0)
 	);
 #endif
 }

 static ssize_t full_write_or_warn(const void *buf, size_t len,
 	const char *const filename)
 {
 	ssize_t n = full_write(ofd, buf, len);
 	if (n < 0)
 		bb_perror_msg("writing '%s'", filename);
 	return n;
 }

 static bool write_and_stats(const void *buf, size_t len, size_t obs,
 	const char *filename)
 {
 	ssize_t n = full_write_or_warn(buf, len, filename);
 	if (n < 0)
 		return 1;
 	if ((size_t)n == obs)
 		G.out_full++;
 	else if (n) /* > 0 */
 		G.out_part++;
 #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
 	G.total_bytes += n;
 #endif
 	return 0;
 }

 #if ENABLE_LFS
 # define XATOU_SFX xatoull_sfx
 #else
 # define XATOU_SFX xatoul_sfx
 #endif

 int dd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int dd_main(int argc UNUSED_PARAM, char **argv)
 {
 	enum {
 		/* Must be in the same order as OP_conv_XXX! */
 		/* (see "flags |= (1 << what)" below) */
 		FLAG_NOTRUNC = (1 << 0) * ENABLE_FEATURE_DD_IBS_OBS,
 		FLAG_SYNC    = (1 << 1) * ENABLE_FEATURE_DD_IBS_OBS,
 		FLAG_NOERROR = (1 << 2) * ENABLE_FEATURE_DD_IBS_OBS,
 		FLAG_FSYNC   = (1 << 3) * ENABLE_FEATURE_DD_IBS_OBS,
 		FLAG_SWAB    = (1 << 4) * ENABLE_FEATURE_DD_IBS_OBS,
 		/* end of conv flags */
 		FLAG_TWOBUFS = (1 << 5) * ENABLE_FEATURE_DD_IBS_OBS,
 		FLAG_COUNT   = 1 << 6,
 	};
 	static const char keywords[] ALIGN1 =
 		"bs\0""count\0""seek\0""skip\0""if\0""of\0"
 #if ENABLE_FEATURE_DD_IBS_OBS
 		"ibs\0""obs\0""conv\0"
 #endif
 		;
 #if ENABLE_FEATURE_DD_IBS_OBS
 	static const char conv_words[] ALIGN1 =
 		"notrunc\0""sync\0""noerror\0""fsync\0""swab\0";
 #endif
 	enum {
 		OP_bs = 0,
 		OP_count,
 		OP_seek,
 		OP_skip,
 		OP_if,
 		OP_of,
 #if ENABLE_FEATURE_DD_IBS_OBS
 		OP_ibs,
 		OP_obs,
 		OP_conv,
 		/* Must be in the same order as FLAG_XXX! */
 		OP_conv_notrunc = 0,
 		OP_conv_sync,
 		OP_conv_noerror,
 		OP_conv_fsync,
 		OP_conv_swab,
 	/* Unimplemented conv=XXX: */
 	//nocreat       do not create the output file
 	//excl          fail if the output file already exists
 	//fdatasync     physically write output file data before finishing
 	//lcase         change upper case to lower case
 	//ucase         change lower case to upper case
 	//block         pad newline-terminated records with spaces to cbs-size
 	//unblock       replace trailing spaces in cbs-size records with newline
 	//ascii         from EBCDIC to ASCII
 	//ebcdic        from ASCII to EBCDIC
 	//ibm           from ASCII to alternate EBCDIC
 	/* Partially implemented: */
 	//swab          swap every pair of input bytes: will abort on non-even reads
 #endif
 	};
 	smallint exitcode = EXIT_FAILURE;
 	int i;
 	size_t ibs = 512;
 	char *ibuf;
 #if ENABLE_FEATURE_DD_IBS_OBS
 	size_t obs = 512;
 	char *obuf;
 #else
 # define obs  ibs
 # define obuf ibuf
 #endif
 	/* These are all zeroed at once! */
 	struct {
 		int flags;
 		size_t oc;
 		ssize_t prev_read_size; /* for detecting swab failure */
 		off_t count;
 		off_t seek, skip;
 		const char *infile, *outfile;
 	} Z;
 #define flags   (Z.flags  )
 #define oc      (Z.oc     )
 #define prev_read_size (Z.prev_read_size)
 #define count   (Z.count  )
 #define seek    (Z.seek   )
 #define skip    (Z.skip   )
 #define infile  (Z.infile )
 #define outfile (Z.outfile)

 	memset(&Z, 0, sizeof(Z));
 	INIT_G();
 	//fflush_all(); - is this needed because of NOEXEC?

 	for (i = 1; argv[i]; i++) {
 		int what;
 		char *val;
 		char *arg = argv[i];

 #if ENABLE_DESKTOP
 		/* "dd --". NB: coreutils 6.9 will complain if they see
 		 * more than one of them. We wouldn't. */
 		if (arg[0] == '-' && arg[1] == '-' && arg[2] == '\0')
 			continue;
 #endif
 		val = strchr(arg, '=');
 		if (val == NULL)
 			bb_show_usage();
 		*val = '\0';
 		what = index_in_strings(keywords, arg);
 		if (what < 0)
 			bb_show_usage();
 		/* *val = '='; - to preserve ps listing? */
 		val++;
 #if ENABLE_FEATURE_DD_IBS_OBS
 		if (what == OP_ibs) {
 			/* Must fit into positive ssize_t */
 			ibs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, dd_suffixes);
 			/*continue;*/
 		}
 		if (what == OP_obs) {
 			obs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, dd_suffixes);
 			/*continue;*/
 		}
 		if (what == OP_conv) {
 			while (1) {
 				int n;
 				/* find ',', replace them with NUL so we can use val for
 				 * index_in_strings() without copying.
 				 * We rely on val being non-null, else strchr would fault.
 				 */
 				arg = strchr(val, ',');
 				if (arg)
 					*arg = '\0';
 				n = index_in_strings(conv_words, val);
 				if (n < 0)
 					bb_error_msg_and_die(bb_msg_invalid_arg, val, "conv");
 				flags |= (1 << n);
 				if (!arg) /* no ',' left, so this was the last specifier */
 					break;
 				/* *arg = ','; - to preserve ps listing? */
 				val = arg + 1; /* skip this keyword and ',' */
 			}
 			/*continue;*/
 		}
 #endif
 		if (what == OP_bs) {
 			ibs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, dd_suffixes);
 			obs = ibs;
 			/*continue;*/
 		}
 		/* These can be large: */
 		if (what == OP_count) {
 			flags |= FLAG_COUNT;
 			count = XATOU_SFX(val, dd_suffixes);
 			/*continue;*/
 		}
 		if (what == OP_seek) {
 			seek = XATOU_SFX(val, dd_suffixes);
 			/*continue;*/
 		}
 		if (what == OP_skip) {
 			skip = XATOU_SFX(val, dd_suffixes);
 			/*continue;*/
 		}
 		if (what == OP_if) {
 			infile = val;
 			/*continue;*/
 		}
 		if (what == OP_of) {
 			outfile = val;
 			/*continue;*/
 		}
 	} /* end of "for (argv[i])" */

 //XXX:FIXME for huge ibs or obs, malloc'ing them isn't the brightest idea ever
 	ibuf = xmalloc(ibs);
 	obuf = ibuf;
 #if ENABLE_FEATURE_DD_IBS_OBS
 	if (ibs != obs) {
 		flags |= FLAG_TWOBUFS;
 		obuf = xmalloc(obs);
 	}
 #endif

 #if ENABLE_FEATURE_DD_SIGNAL_HANDLING
 	signal_SA_RESTART_empty_mask(SIGUSR1, dd_output_status);
 #endif
 #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
 	G.begin_time_us = monotonic_us();
 #endif

 	if (infile) {
 		xmove_fd(xopen(infile, O_RDONLY), ifd);
 	} else {
 		infile = bb_msg_standard_input;
 	}
 	if (outfile) {
 		int oflag = O_WRONLY | O_CREAT;

 		if (!seek && !(flags & FLAG_NOTRUNC))
 			oflag |= O_TRUNC;

 		xmove_fd(xopen(outfile, oflag), ofd);

 		if (seek && !(flags & FLAG_NOTRUNC)) {
 			if (ftruncate(ofd, seek * obs) < 0) {
 				struct stat st;

 				if (fstat(ofd, &st) < 0
 				 || S_ISREG(st.st_mode)
 				 || S_ISDIR(st.st_mode)
 				) {
 					goto die_outfile;
 				}
 			}
 		}
 	} else {
 		outfile = bb_msg_standard_output;
 	}
 	if (skip) {
 		if (lseek(ifd, skip * ibs, SEEK_CUR) < 0) {
 			do {
 				ssize_t n = safe_read(ifd, ibuf, ibs);
 				if (n < 0)
 					goto die_infile;
 				if (n == 0)
 					break;
 			} while (--skip != 0);
 		}
 	}
 	if (seek) {
 		if (lseek(ofd, seek * obs, SEEK_CUR) < 0)
 			goto die_outfile;
 	}

 	while (!(flags & FLAG_COUNT) || (G.in_full + G.in_part != count)) {
 		ssize_t n;

 		n = safe_read(ifd, ibuf, ibs);
 		if (n == 0)
 			break;
 		if (n < 0) {
 			/* "Bad block" */
 			if (!(flags & FLAG_NOERROR))
 				goto die_infile;
 			bb_simple_perror_msg(infile);
 			/* GNU dd with conv=noerror skips over bad blocks */
 			xlseek(ifd, ibs, SEEK_CUR);
 			/* conv=noerror,sync writes NULs,
 			 * conv=noerror just ignores input bad blocks */
 			n = 0;
 		}
 		if (flags & FLAG_SWAB) {
 			uint16_t *p16;
 			ssize_t n2;

 			/* Our code allows only last read to be odd-sized */
 			if (prev_read_size & 1)
 				bb_error_msg_and_die("can't swab %lu byte buffer",
 						(unsigned long)prev_read_size);
 			prev_read_size = n;

 			/* If n is odd, last byte is not swapped:
 			 *  echo -n "qwe" | dd conv=swab
 			 * prints "wqe".
 			 */
 			p16 = (void*) ibuf;
 			n2 = (n >> 1);
 			while (--n2 >= 0) {
 				*p16 = bswap_16(*p16);
 				p16++;
 			}
 		}
 		if ((size_t)n == ibs)
 			G.in_full++;
 		else {
 			G.in_part++;
 			if (flags & FLAG_SYNC) {
 				memset(ibuf + n, 0, ibs - n);
 				n = ibs;
 			}
 		}
 		if (flags & FLAG_TWOBUFS) {
 			char *tmp = ibuf;
 			while (n) {
 				size_t d = obs - oc;

 				if (d > (size_t)n)
 					d = n;
 				memcpy(obuf + oc, tmp, d);
 				n -= d;
 				tmp += d;
 				oc += d;
 				if (oc == obs) {
 					if (write_and_stats(obuf, obs, obs, outfile))
 						goto out_status;
 					oc = 0;
 				}
 			}
 		} else {
 			if (write_and_stats(ibuf, n, obs, outfile))
 				goto out_status;
 		}

 		if (flags & FLAG_FSYNC) {
 			if (fsync(ofd) < 0)
 				goto die_outfile;
 		}
 	}

 	if (ENABLE_FEATURE_DD_IBS_OBS && oc) {
 		if (write_and_stats(obuf, oc, obs, outfile))
 			goto out_status;
 	}
 	if (close(ifd) < 0) {
  die_infile:
 		bb_simple_perror_msg_and_die(infile);
 	}

 	if (close(ofd) < 0) {
  die_outfile:
 		bb_simple_perror_msg_and_die(outfile);
 	}

 	exitcode = EXIT_SUCCESS;
  out_status:
 	dd_output_status(0);

 	if (ENABLE_FEATURE_CLEAN_UP) {
 		free(obuf);
 		if (flags & FLAG_TWOBUFS)
 			free(ibuf);
 	}

 	return exitcode;
 }
	/* vi: set sw=4 ts=4: */
	/*
	* Mini dd implementation for busybox
	*
	*
	* Copyright (C) 2000,2001 Matt Kraai
	*
	* Licensed under GPLv2 or later, see file LICENSE in this source tree.
	*/

	//usage:#define dd_trivial_usage
	//usage: "[if=FILE] [of=FILE] " IF_FEATURE_DD_IBS_OBS("[ibs=N] [obs=N] ") "[bs=N] [count=N] [skip=N]\n"
	//usage: " [seek=N]" IF_FEATURE_DD_IBS_OBS(" [conv=notrunc\|noerror\|sync\|fsync]")
	//usage:#define dd_full_usage "\n\n"
	//usage: "Copy a file with converting and formatting\n"
	//usage: "\n if=FILE Read from FILE instead of stdin"
	//usage: "\n of=FILE Write to FILE instead of stdout"
	//usage: "\n bs=N Read and write N bytes at a time"
	//usage: IF_FEATURE_DD_IBS_OBS(
	//usage: "\n ibs=N Read N bytes at a time"
	//usage: )
	//usage: IF_FEATURE_DD_IBS_OBS(
	//usage: "\n obs=N Write N bytes at a time"
	//usage: )
	//usage: "\n count=N Copy only N input blocks"
	//usage: "\n skip=N Skip N input blocks"
	//usage: "\n seek=N Skip N output blocks"
	//usage: IF_FEATURE_DD_IBS_OBS(
	//usage: "\n conv=notrunc Don't truncate output file"
	//usage: "\n conv=noerror Continue after read errors"
	//usage: "\n conv=sync Pad blocks with zeros"
	//usage: "\n conv=fsync Physically write data out before finishing"
	//usage: "\n conv=swab Swap every pair of bytes"
	//usage: )
	//usage: "\n"
	//usage: "\nN may be suffixed by c (1), w (2), b (512), kD (1000), k (1024), MD, M, GD, G"
	//usage:
	//usage:#define dd_example_usage
	//usage: "$ dd if=/dev/zero of=/dev/ram1 bs=1M count=4\n"
	//usage: "4+0 records in\n"
	//usage: "4+0 records out\n"

	#include "libbb.h"

	/* This is a NOEXEC applet. Be very careful! */


	enum {
	ifd = STDIN_FILENO,
	ofd = STDOUT_FILENO,
	};

	static const struct suffix_mult dd_suffixes[] = {
	{ "c", 1 },
	{ "w", 2 },
	{ "b", 512 },
	{ "kD", 1000 },
	{ "k", 1024 },
	{ "K", 1024 }, /* compat with coreutils dd */
	{ "MD", 1000000 },
	{ "M", 1048576 },
	{ "GD", 1000000000 },
	{ "G", 1073741824 },
	{ "", 0 }
	};

	struct globals {
	off_t out_full, out_part, in_full, in_part;
	#if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
	unsigned long long total_bytes;
	unsigned long long begin_time_us;
	#endif
	} FIX_ALIASING;
	#define G ((struct globals)&bb_common_bufsiz1)
	#define INIT_G() do { \
	/* we have to zero it out because of NOEXEC */ \
	memset(&G, 0, sizeof(G)); \
	} while (0)


	static void dd_output_status(int UNUSED_PARAM cur_signal)
	{
	#if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
	double seconds;
	unsigned long long bytes_sec;
	unsigned long long now_us = monotonic_us(); /* before fprintf */
	#endif

	/* Deliberately using %u, not %d */
	fprintf(stderr, "%"OFF_FMT"u+%"OFF_FMT"u records in\n"
	"%"OFF_FMT"u+%"OFF_FMT"u records out\n",
	G.in_full, G.in_part,
	G.out_full, G.out_part);

	#if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
	fprintf(stderr, "%llu bytes (%sB) copied, ",
	G.total_bytes,
	/* show fractional digit, use suffixes */
	make_human_readable_str(G.total_bytes, 1, 0)
	);
	/* Corner cases:
	* ./busybox dd </dev/null >/dev/null
	* ./busybox dd bs=1M count=2000 </dev/zero >/dev/null
	* (echo DONE) \| ./busybox dd >/dev/null
	* (sleep 1; echo DONE) \| ./busybox dd >/dev/null
	*/
	seconds = (now_us - G.begin_time_us) / 1000000.0;
	bytes_sec = G.total_bytes / seconds;
	fprintf(stderr, "%f seconds, %sB/s\n",
	seconds,
	/* show fractional digit, use suffixes */
	make_human_readable_str(bytes_sec, 1, 0)
	);
	#endif
	}

	static ssize_t full_write_or_warn(const void *buf, size_t len,
	const char *const filename)
	{
	ssize_t n = full_write(ofd, buf, len);
	if (n < 0)
	bb_perror_msg("writing '%s'", filename);
	return n;
	}

	static bool write_and_stats(const void *buf, size_t len, size_t obs,
	const char *filename)
	{
	ssize_t n = full_write_or_warn(buf, len, filename);
	if (n < 0)
	return 1;
	if ((size_t)n == obs)
	G.out_full++;
	else if (n) /* > 0 */
	G.out_part++;
	#if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
	G.total_bytes += n;
	#endif
	return 0;
	}

	#if ENABLE_LFS
	# define XATOU_SFX xatoull_sfx
	#else
	# define XATOU_SFX xatoul_sfx
	#endif

	int dd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
	int dd_main(int argc UNUSED_PARAM, char **argv)
	{
	enum {
	/* Must be in the same order as OP_conv_XXX! */
	/* (see "flags \|= (1 << what)" below) */
	FLAG_NOTRUNC = (1 << 0) * ENABLE_FEATURE_DD_IBS_OBS,
	FLAG_SYNC = (1 << 1) * ENABLE_FEATURE_DD_IBS_OBS,
	FLAG_NOERROR = (1 << 2) * ENABLE_FEATURE_DD_IBS_OBS,
	FLAG_FSYNC = (1 << 3) * ENABLE_FEATURE_DD_IBS_OBS,
	FLAG_SWAB = (1 << 4) * ENABLE_FEATURE_DD_IBS_OBS,
	/* end of conv flags */
	FLAG_TWOBUFS = (1 << 5) * ENABLE_FEATURE_DD_IBS_OBS,
	FLAG_COUNT = 1 << 6,
	};
	static const char keywords[] ALIGN1 =
	"bs\0""count\0""seek\0""skip\0""if\0""of\0"
	#if ENABLE_FEATURE_DD_IBS_OBS
	"ibs\0""obs\0""conv\0"
	#endif
	;
	#if ENABLE_FEATURE_DD_IBS_OBS
	static const char conv_words[] ALIGN1 =
	"notrunc\0""sync\0""noerror\0""fsync\0""swab\0";
	#endif
	enum {
	OP_bs = 0,
	OP_count,
	OP_seek,
	OP_skip,
	OP_if,
	OP_of,
	#if ENABLE_FEATURE_DD_IBS_OBS
	OP_ibs,
	OP_obs,
	OP_conv,
	/* Must be in the same order as FLAG_XXX! */
	OP_conv_notrunc = 0,
	OP_conv_sync,
	OP_conv_noerror,
	OP_conv_fsync,
	OP_conv_swab,
	/* Unimplemented conv=XXX: */
	//nocreat do not create the output file
	//excl fail if the output file already exists
	//fdatasync physically write output file data before finishing
	//lcase change upper case to lower case
	//ucase change lower case to upper case
	//block pad newline-terminated records with spaces to cbs-size
	//unblock replace trailing spaces in cbs-size records with newline
	//ascii from EBCDIC to ASCII
	//ebcdic from ASCII to EBCDIC
	//ibm from ASCII to alternate EBCDIC
	/* Partially implemented: */
	//swab swap every pair of input bytes: will abort on non-even reads
	#endif
	};
	smallint exitcode = EXIT_FAILURE;
	int i;
	size_t ibs = 512;
	char *ibuf;
	#if ENABLE_FEATURE_DD_IBS_OBS
	size_t obs = 512;
	char *obuf;
	#else
	# define obs ibs
	# define obuf ibuf
	#endif
	/* These are all zeroed at once! */
	struct {
	int flags;
	size_t oc;
	ssize_t prev_read_size; /* for detecting swab failure */
	off_t count;
	off_t seek, skip;
	const char infile, outfile;
	} Z;
	#define flags (Z.flags )
	#define oc (Z.oc )
	#define prev_read_size (Z.prev_read_size)
	#define count (Z.count )
	#define seek (Z.seek )
	#define skip (Z.skip )
	#define infile (Z.infile )
	#define outfile (Z.outfile)

	memset(&Z, 0, sizeof(Z));
	INIT_G();
	//fflush_all(); - is this needed because of NOEXEC?

	for (i = 1; argv[i]; i++) {
	int what;
	char *val;
	char *arg = argv[i];

	#if ENABLE_DESKTOP
	/* "dd --". NB: coreutils 6.9 will complain if they see
	* more than one of them. We wouldn't. */
	if (arg[0] == '-' && arg[1] == '-' && arg[2] == '\0')
	continue;
	#endif
	val = strchr(arg, '=');
	if (val == NULL)
	bb_show_usage();
	*val = '\0';
	what = index_in_strings(keywords, arg);
	if (what < 0)
	bb_show_usage();
	/* val = '='; - to preserve ps listing? /
	val++;
	#if ENABLE_FEATURE_DD_IBS_OBS
	if (what == OP_ibs) {
	/* Must fit into positive ssize_t */
	ibs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, dd_suffixes);
	/continue;/
	}
	if (what == OP_obs) {
	obs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, dd_suffixes);
	/continue;/
	}
	if (what == OP_conv) {
	while (1) {
	int n;
	/* find ',', replace them with NUL so we can use val for
	* index_in_strings() without copying.
	* We rely on val being non-null, else strchr would fault.
	*/
	arg = strchr(val, ',');
	if (arg)
	*arg = '\0';
	n = index_in_strings(conv_words, val);
	if (n < 0)
	bb_error_msg_and_die(bb_msg_invalid_arg, val, "conv");
	flags \|= (1 << n);
	if (!arg) /* no ',' left, so this was the last specifier */
	break;
	/* arg = ','; - to preserve ps listing? /
	val = arg + 1; /* skip this keyword and ',' */
	}
	/continue;/
	}
	#endif
	if (what == OP_bs) {
	ibs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, dd_suffixes);
	obs = ibs;
	/continue;/
	}
	/* These can be large: */
	if (what == OP_count) {
	flags \|= FLAG_COUNT;
	count = XATOU_SFX(val, dd_suffixes);
	/continue;/
	}
	if (what == OP_seek) {
	seek = XATOU_SFX(val, dd_suffixes);
	/continue;/
	}
	if (what == OP_skip) {
	skip = XATOU_SFX(val, dd_suffixes);
	/continue;/
	}
	if (what == OP_if) {
	infile = val;
	/continue;/
	}
	if (what == OP_of) {
	outfile = val;
	/continue;/
	}
	} /* end of "for (argv[i])" */

	//XXX:FIXME for huge ibs or obs, malloc'ing them isn't the brightest idea ever
	ibuf = xmalloc(ibs);
	obuf = ibuf;
	#if ENABLE_FEATURE_DD_IBS_OBS
	if (ibs != obs) {
	flags \|= FLAG_TWOBUFS;
	obuf = xmalloc(obs);
	}
	#endif

	#if ENABLE_FEATURE_DD_SIGNAL_HANDLING
	signal_SA_RESTART_empty_mask(SIGUSR1, dd_output_status);
	#endif
	#if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
	G.begin_time_us = monotonic_us();
	#endif

	if (infile) {
	xmove_fd(xopen(infile, O_RDONLY), ifd);
	} else {
	infile = bb_msg_standard_input;
	}
	if (outfile) {
	int oflag = O_WRONLY \| O_CREAT;

	if (!seek && !(flags & FLAG_NOTRUNC))
	oflag \|= O_TRUNC;

	xmove_fd(xopen(outfile, oflag), ofd);

	if (seek && !(flags & FLAG_NOTRUNC)) {
	if (ftruncate(ofd, seek * obs) < 0) {
	struct stat st;

	if (fstat(ofd, &st) < 0
	\|\| S_ISREG(st.st_mode)
	\|\| S_ISDIR(st.st_mode)
	) {
	goto die_outfile;
	}
	}
	}
	} else {
	outfile = bb_msg_standard_output;
	}
	if (skip) {
	if (lseek(ifd, skip * ibs, SEEK_CUR) < 0) {
	do {
	ssize_t n = safe_read(ifd, ibuf, ibs);
	if (n < 0)
	goto die_infile;
	if (n == 0)
	break;
	} while (--skip != 0);
	}
	}
	if (seek) {
	if (lseek(ofd, seek * obs, SEEK_CUR) < 0)
	goto die_outfile;
	}

	while (!(flags & FLAG_COUNT) \|\| (G.in_full + G.in_part != count)) {
	ssize_t n;

	n = safe_read(ifd, ibuf, ibs);
	if (n == 0)
	break;
	if (n < 0) {
	/* "Bad block" */
	if (!(flags & FLAG_NOERROR))
	goto die_infile;
	bb_simple_perror_msg(infile);
	/* GNU dd with conv=noerror skips over bad blocks */
	xlseek(ifd, ibs, SEEK_CUR);
	/* conv=noerror,sync writes NULs,
	* conv=noerror just ignores input bad blocks */
	n = 0;
	}
	if (flags & FLAG_SWAB) {
	uint16_t *p16;
	ssize_t n2;

	/* Our code allows only last read to be odd-sized */
	if (prev_read_size & 1)
	bb_error_msg_and_die("can't swab %lu byte buffer",
	(unsigned long)prev_read_size);
	prev_read_size = n;

	/* If n is odd, last byte is not swapped:
	* echo -n "qwe" \| dd conv=swab
	* prints "wqe".
	*/
	p16 = (void*) ibuf;
	n2 = (n >> 1);
	while (--n2 >= 0) {
	p16 = bswap_16(p16);
	p16++;
	}
	}
	if ((size_t)n == ibs)
	G.in_full++;
	else {
	G.in_part++;
	if (flags & FLAG_SYNC) {
	memset(ibuf + n, 0, ibs - n);
	n = ibs;
	}
	}
	if (flags & FLAG_TWOBUFS) {
	char *tmp = ibuf;
	while (n) {
	size_t d = obs - oc;

	if (d > (size_t)n)
	d = n;
	memcpy(obuf + oc, tmp, d);
	n -= d;
	tmp += d;
	oc += d;
	if (oc == obs) {
	if (write_and_stats(obuf, obs, obs, outfile))
	goto out_status;
	oc = 0;
	}
	}
	} else {
	if (write_and_stats(ibuf, n, obs, outfile))
	goto out_status;
	}

	if (flags & FLAG_FSYNC) {
	if (fsync(ofd) < 0)
	goto die_outfile;
	}
	}

	if (ENABLE_FEATURE_DD_IBS_OBS && oc) {
	if (write_and_stats(obuf, oc, obs, outfile))
	goto out_status;
	}
	if (close(ifd) < 0) {
	die_infile:
	bb_simple_perror_msg_and_die(infile);
	}

	if (close(ofd) < 0) {
	die_outfile:
	bb_simple_perror_msg_and_die(outfile);
	}

	exitcode = EXIT_SUCCESS;
	out_status:
	dd_output_status(0);

	if (ENABLE_FEATURE_CLEAN_UP) {
	free(obuf);
	if (flags & FLAG_TWOBUFS)
	free(ibuf);
	}

	return exitcode;
	}