busybox/coreutils/dd.c
Denys Vlasenko f560422fa0 Big cleanup in config help and description
Redundant help texts (one which only repeats the description)
are deleted.

Descriptions and help texts are trimmed.

Some config options are moved, even across menus.

No config option _names_ are changed.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2017-01-10 14:58:54 +01:00

569 lines
15 KiB
C

/* 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.
*/
//config:config DD
//config: bool "dd"
//config: default y
//config: help
//config: dd copies a file (from standard input to standard output,
//config: by default) using specific input and output blocksizes,
//config: while optionally performing conversions on it.
//config:
//config:config FEATURE_DD_SIGNAL_HANDLING
//config: bool "Enable signal handling for status reporting"
//config: default y
//config: depends on DD
//config: help
//config: Sending a SIGUSR1 signal to a running `dd' process makes it
//config: print to standard error the number of records read and written
//config: so far, then to resume copying.
//config:
//config: $ dd if=/dev/zero of=/dev/null &
//config: $ pid=$!; kill -USR1 $pid; sleep 1; kill $pid
//config: 10899206+0 records in
//config: 10899206+0 records out
//config:
//config:config FEATURE_DD_THIRD_STATUS_LINE
//config: bool "Enable the third status line upon signal"
//config: default y
//config: depends on DD && FEATURE_DD_SIGNAL_HANDLING
//config: help
//config: Displays a coreutils-like third status line with transferred bytes,
//config: elapsed time and speed.
//config:
//config:config FEATURE_DD_IBS_OBS
//config: bool "Enable ibs, obs and conv options"
//config: default y
//config: depends on DD
//config: help
//config: Enable support for writing a certain number of bytes in and out,
//config: at a time, and performing conversions on the data stream.
//config:
//config:config FEATURE_DD_STATUS
//config: bool "Enable status display options"
//config: default y
//config: depends on DD
//config: help
//config: Enable support for status=noxfer/none option.
//applet:IF_DD(APPLET_NOEXEC(dd, dd, BB_DIR_BIN, BB_SUID_DROP, dd))
//kbuild:lib-$(CONFIG_DD) += dd.o
//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] [iflag=skip_bytes]")
//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: "\n iflag=skip_bytes skip=N is in bytes"
//usage: )
//usage: IF_FEATURE_DD_STATUS(
//usage: "\n status=noxfer Suppress rate output"
//usage: "\n status=none Suppress all output"
//usage: )
//usage: "\n"
//usage: "\nN may be suffixed by c (1), w (2), b (512), kB (1000), k (1024), MB, M, GB, 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"
#include "common_bufsiz.h"
/* This is a NOEXEC applet. Be very careful! */
enum {
ifd = STDIN_FILENO,
ofd = STDOUT_FILENO,
};
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
int flags;
} FIX_ALIASING;
#define G (*(struct globals*)bb_common_bufsiz1)
#define INIT_G() do { \
setup_common_bufsiz(); \
/* we have to zero it out because of NOEXEC */ \
memset(&G, 0, sizeof(G)); \
} while (0)
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 */
/* start of input flags */
FLAG_IFLAG_SHIFT = 5,
FLAG_SKIP_BYTES = (1 << 5) * ENABLE_FEATURE_DD_IBS_OBS,
/* end of input flags */
FLAG_TWOBUFS = (1 << 6) * ENABLE_FEATURE_DD_IBS_OBS,
FLAG_COUNT = 1 << 7,
FLAG_STATUS = 1 << 8,
FLAG_STATUS_NONE = 1 << 9,
FLAG_STATUS_NOXFER = 1 << 10,
};
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
# if ENABLE_FEATURE_DD_STATUS
if (G.flags & FLAG_STATUS_NOXFER) /* status=noxfer active? */
return;
//TODO: should status=none make dd stop reacting to USR1 entirely?
//So far we react to it (we print the stats),
//status=none only suppresses final, non-USR1 generated status message.
# endif
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
#if ENABLE_FEATURE_DD_IBS_OBS
static int parse_comma_flags(char *val, const char *words, const char *error_in)
{
int flags = 0;
while (1) {
int n;
char *arg;
/* 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(words, val);
if (n < 0)
bb_error_msg_and_die(bb_msg_invalid_arg_to, val, error_in);
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 ',' */
}
return flags;
}
#endif
int dd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int dd_main(int argc UNUSED_PARAM, char **argv)
{
static const char keywords[] ALIGN1 =
"bs\0""count\0""seek\0""skip\0""if\0""of\0"IF_FEATURE_DD_STATUS("status\0")
#if ENABLE_FEATURE_DD_IBS_OBS
"ibs\0""obs\0""conv\0""iflag\0"
#endif
;
#if ENABLE_FEATURE_DD_IBS_OBS
static const char conv_words[] ALIGN1 =
"notrunc\0""sync\0""noerror\0""fsync\0""swab\0";
static const char iflag_words[] ALIGN1 =
"skip_bytes\0";
#endif
#if ENABLE_FEATURE_DD_STATUS
static const char status_words[] ALIGN1 =
"none\0""noxfer\0";
#endif
enum {
OP_bs = 0,
OP_count,
OP_seek,
OP_skip,
OP_if,
OP_of,
IF_FEATURE_DD_STATUS(OP_status,)
#if ENABLE_FEATURE_DD_IBS_OBS
OP_ibs,
OP_obs,
OP_conv,
OP_iflag,
/* 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
OP_iflag_skip_bytes,
#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 {
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 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, cwbkMG_suffixes);
/*continue;*/
}
if (what == OP_obs) {
obs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, cwbkMG_suffixes);
/*continue;*/
}
if (what == OP_conv) {
G.flags |= parse_comma_flags(val, conv_words, "conv");
/*continue;*/
}
if (what == OP_iflag) {
G.flags |= parse_comma_flags(val, iflag_words, "iflag") << FLAG_IFLAG_SHIFT;
/*continue;*/
}
#endif
if (what == OP_bs) {
ibs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, cwbkMG_suffixes);
obs = ibs;
/*continue;*/
}
/* These can be large: */
if (what == OP_count) {
G.flags |= FLAG_COUNT;
count = XATOU_SFX(val, cwbkMG_suffixes);
/*continue;*/
}
if (what == OP_seek) {
seek = XATOU_SFX(val, cwbkMG_suffixes);
/*continue;*/
}
if (what == OP_skip) {
skip = XATOU_SFX(val, cwbkMG_suffixes);
/*continue;*/
}
if (what == OP_if) {
infile = val;
/*continue;*/
}
if (what == OP_of) {
outfile = val;
/*continue;*/
}
#if ENABLE_FEATURE_DD_STATUS
if (what == OP_status) {
int n;
n = index_in_strings(status_words, val);
if (n < 0)
bb_error_msg_and_die(bb_msg_invalid_arg_to, val, "status");
G.flags |= FLAG_STATUS << n;
/*continue;*/
}
#endif
} /* 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) {
G.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 && !(G.flags & FLAG_NOTRUNC))
oflag |= O_TRUNC;
xmove_fd(xopen(outfile, oflag), ofd);
if (seek && !(G.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) {
size_t blocksz = (G.flags & FLAG_SKIP_BYTES) ? 1 : ibs;
if (lseek(ifd, skip * blocksz, SEEK_CUR) < 0) {
do {
ssize_t n = safe_read(ifd, ibuf, blocksz);
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 (!(G.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 (!(G.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 (G.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 (G.flags & FLAG_SYNC) {
memset(ibuf + n, 0, ibs - n);
n = ibs;
}
}
if (G.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 (G.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:
if (!ENABLE_FEATURE_DD_STATUS || !(G.flags & FLAG_STATUS_NONE))
dd_output_status(0);
if (ENABLE_FEATURE_CLEAN_UP) {
free(obuf);
if (G.flags & FLAG_TWOBUFS)
free(ibuf);
}
return exitcode;
}