busybox/coreutils/dd.c
Denys Vlasenko 0ff0b320a2 dd: code shrink
function                                             old     new   delta
dd_main                                             1475    1469      -6

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2013-08-20 12:49:28 +02:00

481 lines
12 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.
*/
//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;
}