1 /* vi: set sw=4 ts=4: */
3 * Mini dd implementation for busybox
5 * Copyright (C) 2000,2001 Matt Kraai
7 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
10 //config: bool "dd (7.1 kb)"
13 //config: dd copies a file (from standard input to standard output,
14 //config: by default) using specific input and output blocksizes,
15 //config: while optionally performing conversions on it.
17 //config:config FEATURE_DD_SIGNAL_HANDLING
18 //config: bool "Enable signal handling for status reporting"
20 //config: depends on DD
22 //config: Sending a SIGUSR1 signal to a running 'dd' process makes it
23 //config: print to standard error the number of records read and written
24 //config: so far, then to resume copying.
26 //config: $ dd if=/dev/zero of=/dev/null &
27 //config: $ pid=$!; kill -USR1 $pid; sleep 1; kill $pid
28 //config: 10899206+0 records in
29 //config: 10899206+0 records out
31 //config:config FEATURE_DD_THIRD_STATUS_LINE
32 //config: bool "Enable the third status line upon signal"
34 //config: depends on DD && FEATURE_DD_SIGNAL_HANDLING
36 //config: Displays a coreutils-like third status line with transferred bytes,
37 //config: elapsed time and speed.
39 //config:config FEATURE_DD_IBS_OBS
40 //config: bool "Enable ibs, obs, iflag and conv options"
42 //config: depends on DD
44 //config: Enable support for writing a certain number of bytes in and out,
45 //config: at a time, and performing conversions on the data stream.
47 //config:config FEATURE_DD_STATUS
48 //config: bool "Enable status display options"
50 //config: depends on DD
52 //config: Enable support for status=noxfer/none option.
54 //applet:IF_DD(APPLET_NOEXEC(dd, dd, BB_DIR_BIN, BB_SUID_DROP, dd))
56 //kbuild:lib-$(CONFIG_DD) += dd.o
58 //usage:#define dd_trivial_usage
59 //usage: "[if=FILE] [of=FILE] " IF_FEATURE_DD_IBS_OBS("[ibs=N] [obs=N] ") "[bs=N] [count=N] [skip=N]\n"
60 //usage: " [seek=N]" IF_FEATURE_DD_IBS_OBS(" [conv=notrunc|noerror|sync|fsync] [iflag=skip_bytes|fullblock]")
61 //usage:#define dd_full_usage "\n\n"
62 //usage: "Copy a file with converting and formatting\n"
63 //usage: "\n if=FILE Read from FILE instead of stdin"
64 //usage: "\n of=FILE Write to FILE instead of stdout"
65 //usage: "\n bs=N Read and write N bytes at a time"
66 //usage: IF_FEATURE_DD_IBS_OBS(
67 //usage: "\n ibs=N Read N bytes at a time"
69 //usage: IF_FEATURE_DD_IBS_OBS(
70 //usage: "\n obs=N Write N bytes at a time"
72 //usage: "\n count=N Copy only N input blocks"
73 //usage: "\n skip=N Skip N input blocks"
74 //usage: "\n seek=N Skip N output blocks"
75 //usage: IF_FEATURE_DD_IBS_OBS(
76 //usage: "\n conv=notrunc Don't truncate output file"
77 //usage: "\n conv=noerror Continue after read errors"
78 //usage: "\n conv=sync Pad blocks with zeros"
79 //usage: "\n conv=fsync Physically write data out before finishing"
80 //usage: "\n conv=swab Swap every pair of bytes"
81 //usage: "\n iflag=skip_bytes skip=N is in bytes"
82 //usage: "\n iflag=fullblock Read full blocks"
84 //usage: IF_FEATURE_DD_STATUS(
85 //usage: "\n status=noxfer Suppress rate output"
86 //usage: "\n status=none Suppress all output"
89 //usage: "\nN may be suffixed by c (1), w (2), b (512), kB (1000), k (1024), MB, M, GB, G"
91 //usage:#define dd_example_usage
92 //usage: "$ dd if=/dev/zero of=/dev/ram1 bs=1M count=4\n"
93 //usage: "4+0 records in\n"
94 //usage: "4+0 records out\n"
97 #include "common_bufsiz.h"
99 /* This is a NOEXEC applet. Be very careful! */
108 off_t out_full, out_part, in_full, in_part;
109 #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
110 unsigned long long total_bytes;
111 unsigned long long begin_time_us;
115 #define G (*(struct globals*)bb_common_bufsiz1)
116 #define INIT_G() do { \
117 setup_common_bufsiz(); \
118 /* we have to zero it out because of NOEXEC */ \
119 memset(&G, 0, sizeof(G)); \
123 /* Must be in the same order as OP_conv_XXX! */
124 /* (see "flags |= (1 << what)" below) */
125 FLAG_NOTRUNC = (1 << 0) * ENABLE_FEATURE_DD_IBS_OBS,
126 FLAG_SYNC = (1 << 1) * ENABLE_FEATURE_DD_IBS_OBS,
127 FLAG_NOERROR = (1 << 2) * ENABLE_FEATURE_DD_IBS_OBS,
128 FLAG_FSYNC = (1 << 3) * ENABLE_FEATURE_DD_IBS_OBS,
129 FLAG_SWAB = (1 << 4) * ENABLE_FEATURE_DD_IBS_OBS,
130 /* end of conv flags */
131 /* start of input flags */
132 FLAG_IFLAG_SHIFT = 5,
133 FLAG_SKIP_BYTES = (1 << 5) * ENABLE_FEATURE_DD_IBS_OBS,
134 FLAG_FULLBLOCK = (1 << 6) * ENABLE_FEATURE_DD_IBS_OBS,
135 /* end of input flags */
136 FLAG_TWOBUFS = (1 << 7) * ENABLE_FEATURE_DD_IBS_OBS,
138 FLAG_STATUS_NONE = 1 << 9,
139 FLAG_STATUS_NOXFER = 1 << 10,
142 static void dd_output_status(int UNUSED_PARAM cur_signal)
144 #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
146 unsigned long long bytes_sec;
147 unsigned long long now_us = monotonic_us(); /* before fprintf */
150 /* Deliberately using %u, not %d */
151 fprintf(stderr, "%"OFF_FMT"u+%"OFF_FMT"u records in\n"
152 "%"OFF_FMT"u+%"OFF_FMT"u records out\n",
153 G.in_full, G.in_part,
154 G.out_full, G.out_part);
156 #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
157 # if ENABLE_FEATURE_DD_STATUS
158 if (G.flags & FLAG_STATUS_NOXFER) /* status=noxfer active? */
160 //TODO: should status=none make dd stop reacting to USR1 entirely?
161 //So far we react to it (we print the stats),
162 //status=none only suppresses final, non-USR1 generated status message.
164 fprintf(stderr, "%llu bytes (%sB) copied, ",
166 /* show fractional digit, use suffixes */
167 make_human_readable_str(G.total_bytes, 1, 0)
170 * ./busybox dd </dev/null >/dev/null
171 * ./busybox dd bs=1M count=2000 </dev/zero >/dev/null
172 * (echo DONE) | ./busybox dd >/dev/null
173 * (sleep 1; echo DONE) | ./busybox dd >/dev/null
175 seconds = (now_us - G.begin_time_us) / 1000000.0;
176 bytes_sec = G.total_bytes / seconds;
177 fprintf(stderr, "%f seconds, %sB/s\n",
179 /* show fractional digit, use suffixes */
180 make_human_readable_str(bytes_sec, 1, 0)
185 static ssize_t full_write_or_warn(const void *buf, size_t len,
186 const char *const filename)
188 ssize_t n = full_write(ofd, buf, len);
190 bb_perror_msg("writing '%s'", filename);
194 static bool write_and_stats(const void *buf, size_t len, size_t obs,
195 const char *filename)
197 ssize_t n = full_write_or_warn(buf, len, filename);
200 #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
203 if ((size_t)n == obs) {
207 if ((size_t)n == len) {
215 # define XATOU_SFX xatoull_sfx
217 # define XATOU_SFX xatoul_sfx
220 #if ENABLE_FEATURE_DD_IBS_OBS
221 static int parse_comma_flags(char *val, const char *words, const char *error_in)
227 /* find ',', replace them with NUL so we can use val for
228 * index_in_strings() without copying.
229 * We rely on val being non-null, else strchr would fault.
231 arg = strchr(val, ',');
234 n = index_in_strings(words, val);
236 bb_error_msg_and_die(bb_msg_invalid_arg_to, val, error_in);
238 if (!arg) /* no ',' left, so this was the last specifier */
240 *arg = ','; /* to preserve ps listing */
241 val = arg + 1; /* skip this keyword and ',' */
247 int dd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
248 int dd_main(int argc UNUSED_PARAM, char **argv)
250 static const char keywords[] ALIGN1 =
251 "bs\0""count\0""seek\0""skip\0""if\0""of\0"IF_FEATURE_DD_STATUS("status\0")
252 #if ENABLE_FEATURE_DD_IBS_OBS
253 "ibs\0""obs\0""conv\0""iflag\0"
256 #if ENABLE_FEATURE_DD_IBS_OBS
257 static const char conv_words[] ALIGN1 =
258 "notrunc\0""sync\0""noerror\0""fsync\0""swab\0";
259 static const char iflag_words[] ALIGN1 =
260 "skip_bytes\0""fullblock\0";
262 #if ENABLE_FEATURE_DD_STATUS
263 static const char status_words[] ALIGN1 =
273 IF_FEATURE_DD_STATUS(OP_status,)
274 #if ENABLE_FEATURE_DD_IBS_OBS
279 /* Must be in the same order as FLAG_XXX! */
285 /* Unimplemented conv=XXX: */
286 //nocreat do not create the output file
287 //excl fail if the output file already exists
288 //fdatasync physically write output file data before finishing
289 //lcase change upper case to lower case
290 //ucase change lower case to upper case
291 //block pad newline-terminated records with spaces to cbs-size
292 //unblock replace trailing spaces in cbs-size records with newline
293 //ascii from EBCDIC to ASCII
294 //ebcdic from ASCII to EBCDIC
295 //ibm from ASCII to alternate EBCDIC
296 /* Partially implemented: */
297 //swab swap every pair of input bytes: will abort on non-even reads
302 smallint exitcode = EXIT_FAILURE;
306 #if ENABLE_FEATURE_DD_IBS_OBS
313 /* These are all zeroed at once! */
316 ssize_t prev_read_size; /* for detecting swab failure */
319 const char *infile, *outfile;
322 #define prev_read_size (Z.prev_read_size)
323 #define count (Z.count )
324 #define seek (Z.seek )
325 #define skip (Z.skip )
326 #define infile (Z.infile )
327 #define outfile (Z.outfile)
329 memset(&Z, 0, sizeof(Z));
331 //fflush_all(); - is this needed because of NOEXEC?
333 for (i = 1; argv[i]; i++) {
339 /* "dd --". NB: coreutils 6.9 will complain if they see
340 * more than one of them. We wouldn't. */
341 if (arg[0] == '-' && arg[1] == '-' && arg[2] == '\0')
344 val = strchr(arg, '=');
348 what = index_in_strings(keywords, arg);
351 /* *val = '='; - to preserve ps listing? */
353 #if ENABLE_FEATURE_DD_IBS_OBS
354 if (what == OP_ibs) {
355 /* Must fit into positive ssize_t */
356 ibs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, cwbkMG_suffixes);
359 if (what == OP_obs) {
360 obs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, cwbkMG_suffixes);
363 if (what == OP_conv) {
364 G.flags |= parse_comma_flags(val, conv_words, "conv");
367 if (what == OP_iflag) {
368 G.flags |= parse_comma_flags(val, iflag_words, "iflag") << FLAG_IFLAG_SHIFT;
373 ibs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, cwbkMG_suffixes);
377 /* These can be large: */
378 if (what == OP_count) {
379 G.flags |= FLAG_COUNT;
380 count = XATOU_SFX(val, cwbkMG_suffixes);
383 if (what == OP_seek) {
384 seek = XATOU_SFX(val, cwbkMG_suffixes);
387 if (what == OP_skip) {
388 skip = XATOU_SFX(val, cwbkMG_suffixes);
399 #if ENABLE_FEATURE_DD_STATUS
400 if (what == OP_status) {
402 n = index_in_strings(status_words, val);
404 bb_error_msg_and_die(bb_msg_invalid_arg_to, val, "status");
405 G.flags |= FLAG_STATUS_NONE << n;
409 } /* end of "for (argv[i])" */
411 //XXX:FIXME for huge ibs or obs, malloc'ing them isn't the brightest idea ever
414 #if ENABLE_FEATURE_DD_IBS_OBS
416 G.flags |= FLAG_TWOBUFS;
421 #if ENABLE_FEATURE_DD_SIGNAL_HANDLING
422 signal_SA_RESTART_empty_mask(SIGUSR1, dd_output_status);
424 #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
425 G.begin_time_us = monotonic_us();
429 xmove_fd(xopen(infile, O_RDONLY), ifd);
431 infile = bb_msg_standard_input;
434 int oflag = O_WRONLY | O_CREAT;
436 if (!seek && !(G.flags & FLAG_NOTRUNC))
439 xmove_fd(xopen(outfile, oflag), ofd);
441 if (seek && !(G.flags & FLAG_NOTRUNC)) {
442 if (ftruncate(ofd, seek * obs) < 0) {
445 if (fstat(ofd, &st) < 0
446 || S_ISREG(st.st_mode)
447 || S_ISDIR(st.st_mode)
454 outfile = bb_msg_standard_output;
457 size_t blocksz = (G.flags & FLAG_SKIP_BYTES) ? 1 : ibs;
458 if (lseek(ifd, skip * blocksz, SEEK_CUR) < 0) {
461 #if ENABLE_FEATURE_DD_IBS_OBS
462 if (G.flags & FLAG_FULLBLOCK)
463 n = full_read(ifd, ibuf, blocksz);
466 n = safe_read(ifd, ibuf, blocksz);
471 } while (--skip != 0);
475 if (lseek(ofd, seek * obs, SEEK_CUR) < 0)
479 while (!(G.flags & FLAG_COUNT) || (G.in_full + G.in_part != count)) {
481 #if ENABLE_FEATURE_DD_IBS_OBS
482 if (G.flags & FLAG_FULLBLOCK)
483 n = full_read(ifd, ibuf, ibs);
486 n = safe_read(ifd, ibuf, ibs);
491 if (!(G.flags & FLAG_NOERROR))
493 bb_simple_perror_msg(infile);
494 /* GNU dd with conv=noerror skips over bad blocks */
495 xlseek(ifd, ibs, SEEK_CUR);
496 /* conv=noerror,sync writes NULs,
497 * conv=noerror just ignores input bad blocks */
500 if (G.flags & FLAG_SWAB) {
504 /* Our code allows only last read to be odd-sized */
505 if (prev_read_size & 1)
506 bb_error_msg_and_die("can't swab %lu byte buffer",
507 (unsigned long)prev_read_size);
510 /* If n is odd, last byte is not swapped:
511 * echo -n "qwe" | dd conv=swab
517 *p16 = bswap_16(*p16);
521 if ((size_t)n == ibs)
525 if (G.flags & FLAG_SYNC) {
526 memset(ibuf + n, 0, ibs - n);
530 if (G.flags & FLAG_TWOBUFS) {
537 memcpy(obuf + oc, tmp, d);
542 if (write_and_stats(obuf, obs, obs, outfile))
548 if (write_and_stats(ibuf, n, obs, outfile))
553 if (G.flags & FLAG_FSYNC) {
558 if (ENABLE_FEATURE_DD_IBS_OBS && oc) {
559 if (write_and_stats(obuf, oc, obs, outfile))
562 if (close(ifd) < 0) {
564 bb_simple_perror_msg_and_die(infile);
567 if (close(ofd) < 0) {
569 bb_simple_perror_msg_and_die(outfile);
572 exitcode = EXIT_SUCCESS;
574 if (!ENABLE_FEATURE_DD_STATUS || !(G.flags & FLAG_STATUS_NONE))
577 if (ENABLE_FEATURE_CLEAN_UP) {
579 if (G.flags & FLAG_TWOBUFS)