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.
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 $pid
28 //config: 10899206+0 records in
29 //config: 10899206+0 records out
31 //config:config FEATURE_DD_THIRD_STATUS_LINE
32 //config: bool "Enable the third status line upon signal"
34 //config: depends on DD && FEATURE_DD_SIGNAL_HANDLING
36 //config: Displays a coreutils-like third status line with transferred bytes,
37 //config: elapsed time and speed.
39 //config:config FEATURE_DD_IBS_OBS
40 //config: bool "Enable ibs, obs and conv options"
42 //config: depends on DD
44 //config: Enable support for writing a certain number of bytes in and out,
45 //config: at a time, and performing conversions on the data stream.
47 //config:config FEATURE_DD_STATUS
48 //config: bool "Enable status display options"
50 //config: depends on DD
52 //config: Enable support for status=noxfer/none option.
54 //applet:IF_DD(APPLET_NOEXEC(dd, dd, BB_DIR_BIN, BB_SUID_DROP, dd))
56 //kbuild:lib-$(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]")
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"
83 //usage: IF_FEATURE_DD_STATUS(
84 //usage: "\n status=noxfer Suppress rate output"
85 //usage: "\n status=none Suppress all output"
88 //usage: "\nN may be suffixed by c (1), w (2), b (512), kB (1000), k (1024), MB, M, GB, G"
90 //usage:#define dd_example_usage
91 //usage: "$ dd if=/dev/zero of=/dev/ram1 bs=1M count=4\n"
92 //usage: "4+0 records in\n"
93 //usage: "4+0 records out\n"
96 #include "common_bufsiz.h"
98 /* This is a NOEXEC applet. Be very careful! */
107 off_t out_full, out_part, in_full, in_part;
108 #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
109 unsigned long long total_bytes;
110 unsigned long long begin_time_us;
114 #define G (*(struct globals*)bb_common_bufsiz1)
115 #define INIT_G() do { \
116 setup_common_bufsiz(); \
117 /* we have to zero it out because of NOEXEC */ \
118 memset(&G, 0, sizeof(G)); \
122 /* Must be in the same order as OP_conv_XXX! */
123 /* (see "flags |= (1 << what)" below) */
124 FLAG_NOTRUNC = (1 << 0) * ENABLE_FEATURE_DD_IBS_OBS,
125 FLAG_SYNC = (1 << 1) * ENABLE_FEATURE_DD_IBS_OBS,
126 FLAG_NOERROR = (1 << 2) * ENABLE_FEATURE_DD_IBS_OBS,
127 FLAG_FSYNC = (1 << 3) * ENABLE_FEATURE_DD_IBS_OBS,
128 FLAG_SWAB = (1 << 4) * ENABLE_FEATURE_DD_IBS_OBS,
129 /* end of conv flags */
130 /* start of input flags */
131 FLAG_IFLAG_SHIFT = 5,
132 FLAG_SKIP_BYTES = (1 << 5) * ENABLE_FEATURE_DD_IBS_OBS,
133 /* end of input flags */
134 FLAG_TWOBUFS = (1 << 6) * ENABLE_FEATURE_DD_IBS_OBS,
136 FLAG_STATUS = 1 << 8,
137 FLAG_STATUS_NONE = 1 << 9,
138 FLAG_STATUS_NOXFER = 1 << 10,
141 static void dd_output_status(int UNUSED_PARAM cur_signal)
143 #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
145 unsigned long long bytes_sec;
146 unsigned long long now_us = monotonic_us(); /* before fprintf */
149 /* Deliberately using %u, not %d */
150 fprintf(stderr, "%"OFF_FMT"u+%"OFF_FMT"u records in\n"
151 "%"OFF_FMT"u+%"OFF_FMT"u records out\n",
152 G.in_full, G.in_part,
153 G.out_full, G.out_part);
155 #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
156 # if ENABLE_FEATURE_DD_STATUS
157 if (G.flags & FLAG_STATUS_NOXFER) /* status=noxfer active? */
159 //TODO: should status=none make dd stop reacting to USR1 entirely?
160 //So far we react to it (we print the stats),
161 //status=none only suppresses final, non-USR1 generated status message.
163 fprintf(stderr, "%llu bytes (%sB) copied, ",
165 /* show fractional digit, use suffixes */
166 make_human_readable_str(G.total_bytes, 1, 0)
169 * ./busybox dd </dev/null >/dev/null
170 * ./busybox dd bs=1M count=2000 </dev/zero >/dev/null
171 * (echo DONE) | ./busybox dd >/dev/null
172 * (sleep 1; echo DONE) | ./busybox dd >/dev/null
174 seconds = (now_us - G.begin_time_us) / 1000000.0;
175 bytes_sec = G.total_bytes / seconds;
176 fprintf(stderr, "%f seconds, %sB/s\n",
178 /* show fractional digit, use suffixes */
179 make_human_readable_str(bytes_sec, 1, 0)
184 static ssize_t full_write_or_warn(const void *buf, size_t len,
185 const char *const filename)
187 ssize_t n = full_write(ofd, buf, len);
189 bb_perror_msg("writing '%s'", filename);
193 static bool write_and_stats(const void *buf, size_t len, size_t obs,
194 const char *filename)
196 ssize_t n = full_write_or_warn(buf, len, filename);
199 if ((size_t)n == obs)
201 else if (n) /* > 0 */
203 #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
210 # define XATOU_SFX xatoull_sfx
212 # define XATOU_SFX xatoul_sfx
215 #if ENABLE_FEATURE_DD_IBS_OBS
216 static int parse_comma_flags(char *val, const char *words, const char *error_in)
222 /* find ',', replace them with NUL so we can use val for
223 * index_in_strings() without copying.
224 * We rely on val being non-null, else strchr would fault.
226 arg = strchr(val, ',');
229 n = index_in_strings(words, val);
231 bb_error_msg_and_die(bb_msg_invalid_arg_to, val, error_in);
233 if (!arg) /* no ',' left, so this was the last specifier */
235 *arg = ','; /* to preserve ps listing */
236 val = arg + 1; /* skip this keyword and ',' */
242 int dd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
243 int dd_main(int argc UNUSED_PARAM, char **argv)
245 static const char keywords[] ALIGN1 =
246 "bs\0""count\0""seek\0""skip\0""if\0""of\0"IF_FEATURE_DD_STATUS("status\0")
247 #if ENABLE_FEATURE_DD_IBS_OBS
248 "ibs\0""obs\0""conv\0""iflag\0"
251 #if ENABLE_FEATURE_DD_IBS_OBS
252 static const char conv_words[] ALIGN1 =
253 "notrunc\0""sync\0""noerror\0""fsync\0""swab\0";
254 static const char iflag_words[] ALIGN1 =
257 #if ENABLE_FEATURE_DD_STATUS
258 static const char status_words[] ALIGN1 =
268 IF_FEATURE_DD_STATUS(OP_status,)
269 #if ENABLE_FEATURE_DD_IBS_OBS
274 /* Must be in the same order as FLAG_XXX! */
280 /* Unimplemented conv=XXX: */
281 //nocreat do not create the output file
282 //excl fail if the output file already exists
283 //fdatasync physically write output file data before finishing
284 //lcase change upper case to lower case
285 //ucase change lower case to upper case
286 //block pad newline-terminated records with spaces to cbs-size
287 //unblock replace trailing spaces in cbs-size records with newline
288 //ascii from EBCDIC to ASCII
289 //ebcdic from ASCII to EBCDIC
290 //ibm from ASCII to alternate EBCDIC
291 /* Partially implemented: */
292 //swab swap every pair of input bytes: will abort on non-even reads
296 smallint exitcode = EXIT_FAILURE;
300 #if ENABLE_FEATURE_DD_IBS_OBS
307 /* These are all zeroed at once! */
310 ssize_t prev_read_size; /* for detecting swab failure */
313 const char *infile, *outfile;
316 #define prev_read_size (Z.prev_read_size)
317 #define count (Z.count )
318 #define seek (Z.seek )
319 #define skip (Z.skip )
320 #define infile (Z.infile )
321 #define outfile (Z.outfile)
323 memset(&Z, 0, sizeof(Z));
325 //fflush_all(); - is this needed because of NOEXEC?
327 for (i = 1; argv[i]; i++) {
333 /* "dd --". NB: coreutils 6.9 will complain if they see
334 * more than one of them. We wouldn't. */
335 if (arg[0] == '-' && arg[1] == '-' && arg[2] == '\0')
338 val = strchr(arg, '=');
342 what = index_in_strings(keywords, arg);
345 /* *val = '='; - to preserve ps listing? */
347 #if ENABLE_FEATURE_DD_IBS_OBS
348 if (what == OP_ibs) {
349 /* Must fit into positive ssize_t */
350 ibs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, cwbkMG_suffixes);
353 if (what == OP_obs) {
354 obs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, cwbkMG_suffixes);
357 if (what == OP_conv) {
358 G.flags |= parse_comma_flags(val, conv_words, "conv");
361 if (what == OP_iflag) {
362 G.flags |= parse_comma_flags(val, iflag_words, "iflag") << FLAG_IFLAG_SHIFT;
367 ibs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, cwbkMG_suffixes);
371 /* These can be large: */
372 if (what == OP_count) {
373 G.flags |= FLAG_COUNT;
374 count = XATOU_SFX(val, cwbkMG_suffixes);
377 if (what == OP_seek) {
378 seek = XATOU_SFX(val, cwbkMG_suffixes);
381 if (what == OP_skip) {
382 skip = XATOU_SFX(val, cwbkMG_suffixes);
393 #if ENABLE_FEATURE_DD_STATUS
394 if (what == OP_status) {
396 n = index_in_strings(status_words, val);
398 bb_error_msg_and_die(bb_msg_invalid_arg_to, val, "status");
399 G.flags |= FLAG_STATUS << n;
403 } /* end of "for (argv[i])" */
405 //XXX:FIXME for huge ibs or obs, malloc'ing them isn't the brightest idea ever
408 #if ENABLE_FEATURE_DD_IBS_OBS
410 G.flags |= FLAG_TWOBUFS;
415 #if ENABLE_FEATURE_DD_SIGNAL_HANDLING
416 signal_SA_RESTART_empty_mask(SIGUSR1, dd_output_status);
418 #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
419 G.begin_time_us = monotonic_us();
423 xmove_fd(xopen(infile, O_RDONLY), ifd);
425 infile = bb_msg_standard_input;
428 int oflag = O_WRONLY | O_CREAT;
430 if (!seek && !(G.flags & FLAG_NOTRUNC))
433 xmove_fd(xopen(outfile, oflag), ofd);
435 if (seek && !(G.flags & FLAG_NOTRUNC)) {
436 if (ftruncate(ofd, seek * obs) < 0) {
439 if (fstat(ofd, &st) < 0
440 || S_ISREG(st.st_mode)
441 || S_ISDIR(st.st_mode)
448 outfile = bb_msg_standard_output;
451 size_t blocksz = (G.flags & FLAG_SKIP_BYTES) ? 1 : ibs;
452 if (lseek(ifd, skip * blocksz, SEEK_CUR) < 0) {
454 ssize_t n = safe_read(ifd, ibuf, blocksz);
459 } while (--skip != 0);
463 if (lseek(ofd, seek * obs, SEEK_CUR) < 0)
467 while (!(G.flags & FLAG_COUNT) || (G.in_full + G.in_part != count)) {
470 n = safe_read(ifd, ibuf, ibs);
475 if (!(G.flags & FLAG_NOERROR))
477 bb_simple_perror_msg(infile);
478 /* GNU dd with conv=noerror skips over bad blocks */
479 xlseek(ifd, ibs, SEEK_CUR);
480 /* conv=noerror,sync writes NULs,
481 * conv=noerror just ignores input bad blocks */
484 if (G.flags & FLAG_SWAB) {
488 /* Our code allows only last read to be odd-sized */
489 if (prev_read_size & 1)
490 bb_error_msg_and_die("can't swab %lu byte buffer",
491 (unsigned long)prev_read_size);
494 /* If n is odd, last byte is not swapped:
495 * echo -n "qwe" | dd conv=swab
501 *p16 = bswap_16(*p16);
505 if ((size_t)n == ibs)
509 if (G.flags & FLAG_SYNC) {
510 memset(ibuf + n, 0, ibs - n);
514 if (G.flags & FLAG_TWOBUFS) {
521 memcpy(obuf + oc, tmp, d);
526 if (write_and_stats(obuf, obs, obs, outfile))
532 if (write_and_stats(ibuf, n, obs, outfile))
537 if (G.flags & FLAG_FSYNC) {
542 if (ENABLE_FEATURE_DD_IBS_OBS && oc) {
543 if (write_and_stats(obuf, oc, obs, outfile))
546 if (close(ifd) < 0) {
548 bb_simple_perror_msg_and_die(infile);
551 if (close(ofd) < 0) {
553 bb_simple_perror_msg_and_die(outfile);
556 exitcode = EXIT_SUCCESS;
558 if (!ENABLE_FEATURE_DD_STATUS || !(G.flags & FLAG_STATUS_NONE))
561 if (ENABLE_FEATURE_CLEAN_UP) {
563 if (G.flags & FLAG_TWOBUFS)