busybox/coreutils/dd.c

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/* vi: set sw=4 ts=4: */
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/*
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* Mini dd implementation for busybox
*
*
* Copyright (C) 2000,2001 Matt Kraai
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*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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*/
#include <signal.h> /* For FEATURE_DD_SIGNAL_HANDLING */
#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[] = {
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{ "c", 1 },
{ "w", 2 },
{ "b", 512 },
{ "kD", 1000 },
{ "k", 1024 },
{ "K", 1024 }, /* compat with coreutils dd */
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{ "MD", 1000000 },
{ "M", 1048576 },
{ "GD", 1000000000 },
{ "G", 1073741824 },
{ }
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};
struct globals {
off_t out_full, out_part, in_full, in_part;
};
#define G (*(struct globals*)&bb_common_bufsiz1)
/* We have to zero it out because of NOEXEC */
#define INIT_G() memset(&G, 0, sizeof(G))
static void dd_output_status(int ATTRIBUTE_UNUSED cur_signal)
{
/* 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);
}
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 (n == obs)
G.out_full++;
else if (n) /* > 0 */
G.out_part++;
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;
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int dd_main(int argc, char **argv)
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{
enum {
FLAG_SYNC = 1 << 0,
FLAG_NOERROR = 1 << 1,
FLAG_NOTRUNC = 1 << 2,
FLAG_TWOBUFS = 1 << 3,
FLAG_COUNT = 1 << 4,
};
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""notrunc\0""sync\0""noerror\0"
#endif
;
enum {
OP_bs = 1,
OP_count,
OP_seek,
OP_skip,
OP_if,
OP_of,
#if ENABLE_FEATURE_DD_IBS_OBS
OP_ibs,
OP_obs,
OP_conv,
OP_conv_notrunc,
OP_conv_sync,
OP_conv_noerror,
#endif
};
int exitcode = EXIT_FAILURE;
size_t ibs = 512, obs = 512;
ssize_t n, w;
char *ibuf, *obuf;
/* And these are all zeroed at once! */
struct {
int flags;
size_t oc;
off_t count;
off_t seek, skip;
const char *infile, *outfile;
#if ENABLE_FEATURE_DD_SIGNAL_HANDLING
struct sigaction sigact;
#endif
} Z;
#define flags (Z.flags )
#define oc (Z.oc )
#define count (Z.count )
#define seek (Z.seek )
#define skip (Z.skip )
#define infile (Z.infile )
#define outfile (Z.outfile)
#define sigact (Z.sigact )
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memset(&Z, 0, sizeof(Z));
INIT_G();
//fflush(NULL); - is this needed because of NOEXEC?
#if ENABLE_FEATURE_DD_SIGNAL_HANDLING
sigact.sa_handler = dd_output_status;
sigact.sa_flags = SA_RESTART;
/*sigemptyset(&sigact.sa_mask); - memset did it */
sigaction(SIGUSR1, &sigact, NULL);
#endif
for (n = 1; n < argc; n++) {
smalluint key_len;
smalluint what;
char *key;
char *arg = argv[n];
//XXX:FIXME: we reject plain "dd --" This would cost ~20 bytes, so..
//if (*arg == '-' && *++arg == '-' && !*++arg) continue;
key = strstr(arg, "=");
if (key == NULL)
bb_show_usage();
key_len = key - arg + 1;
key = xstrndup(arg, key_len);
what = index_in_strings(keywords, key) + 1;
if (ENABLE_FEATURE_CLEAN_UP)
free(key);
if (what == 0)
bb_show_usage();
arg += key_len;
#if ENABLE_FEATURE_DD_IBS_OBS
if (what == OP_ibs) {
/* Must fit into positive ssize_t */
ibs = xatoul_range_sfx(arg, 1, ((size_t)-1L)/2, dd_suffixes);
continue;
}
if (what == OP_obs) {
obs = xatoul_range_sfx(arg, 1, ((size_t)-1L)/2, dd_suffixes);
continue;
}
if (what == OP_conv) {
while (1) {
/* find ',', replace them with NUL so we can use arg for
* index_in_strings() without copying.
* We rely on arg being non-null, else strchr would fault.
*/
key = strchr(arg, ',');
if (key)
*key = '\0';
what = index_in_strings(keywords, arg) + 1;
if (what < OP_conv_notrunc)
bb_error_msg_and_die(bb_msg_invalid_arg, arg, "conv");
if (what == OP_conv_notrunc)
flags |= FLAG_NOTRUNC;
if (what == OP_conv_sync)
flags |= FLAG_SYNC;
if (what == OP_conv_noerror)
flags |= FLAG_NOERROR;
if (!key) /* no ',' left, so this was the last specifier */
break;
arg = key + 1; /* skip this keyword and ',' */
}
continue;
}
#endif
if (what == OP_bs) {
ibs = obs = xatoul_range_sfx(arg, 1, ((size_t)-1L)/2, dd_suffixes);
continue;
}
/* These can be large: */
if (what == OP_count) {
flags |= FLAG_COUNT;
count = XATOU_SFX(arg, dd_suffixes);
continue;
}
if (what == OP_seek) {
seek = XATOU_SFX(arg, dd_suffixes);
continue;
}
if (what == OP_skip) {
skip = XATOU_SFX(arg, dd_suffixes);
continue;
}
if (what == OP_if) {
infile = arg;
continue;
}
if (what == OP_of)
outfile = arg;
}
//XXX:FIXME for huge ibs or obs, malloc'ing them isn't the brightest idea ever
ibuf = obuf = xmalloc(ibs);
if (ibs != obs) {
flags |= FLAG_TWOBUFS;
obuf = xmalloc(obs);
}
if (infile != NULL)
xmove_fd(xopen(infile, O_RDONLY), ifd);
else {
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infile = bb_msg_standard_input;
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}
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if (outfile != NULL) {
int oflag = O_WRONLY | O_CREAT;
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if (!seek && !(flags & FLAG_NOTRUNC))
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oflag |= O_TRUNC;
xmove_fd(xopen(outfile, oflag), ofd);
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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;
}
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}
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} else {
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outfile = bb_msg_standard_output;
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}
if (skip) {
if (lseek(ifd, skip * ibs, SEEK_CUR) < 0) {
while (skip-- > 0) {
n = safe_read(ifd, ibuf, ibs);
if (n < 0)
goto die_infile;
if (n == 0)
break;
}
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}
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}
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if (seek) {
if (lseek(ofd, seek * obs, SEEK_CUR) < 0)
goto die_outfile;
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}
while (!(flags & FLAG_COUNT) || (G.in_full + G.in_part != count)) {
if (flags & FLAG_NOERROR) /* Pre-zero the buffer if conv=noerror */
memset(ibuf, 0, ibs);
n = safe_read(ifd, ibuf, ibs);
if (n == 0)
break;
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if (n < 0) {
if (!(flags & FLAG_NOERROR))
goto die_infile;
n = ibs;
bb_simple_perror_msg(infile);
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}
if ((size_t)n == ibs)
G.in_full++;
else {
G.in_part++;
if (flags & FLAG_SYNC) {
memset(ibuf + n, '\0', ibs - n);
n = ibs;
}
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}
if (flags & FLAG_TWOBUFS) {
char *tmp = ibuf;
while (n) {
size_t d = obs - oc;
if (d > 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;
}
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if (ENABLE_FEATURE_DD_IBS_OBS && oc) {
w = full_write_or_warn(obuf, oc, outfile);
if (w < 0) goto out_status;
if (w > 0)
G.out_part++;
}
if (close(ifd) < 0) {
die_infile:
bb_simple_perror_msg_and_die(infile);
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}
if (close(ofd) < 0) {
die_outfile:
bb_simple_perror_msg_and_die(outfile);
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}
exitcode = EXIT_SUCCESS;
out_status:
dd_output_status(0);
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return exitcode;
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}