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 "busybox.h"
#include <signal.h> /* For FEATURE_DD_SIGNAL_HANDLING */
static const struct suffix_mult dd_suffixes[] = {
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{ "c", 1 },
{ "w", 2 },
{ "b", 512 },
{ "kD", 1000 },
{ "k", 1024 },
{ "MD", 1000000 },
{ "M", 1048576 },
{ "GD", 1000000000 },
{ "G", 1073741824 },
{ NULL, 0 }
};
static size_t out_full, out_part, in_full, in_part;
static void dd_output_status(int ATTRIBUTE_UNUSED cur_signal)
{
bb_fprintf(stderr, "%ld+%ld records in\n%ld+%ld records out\n",
(long)in_full, (long)in_part,
(long)out_full, (long)out_part);
}
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int dd_main(int argc, char **argv)
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{
#define sync_flag (1<<0)
#define noerror (1<<1)
#define trunc_flag (1<<2)
#define twobufs_flag (1<<3)
int flags = trunc_flag;
size_t count = -1, oc = 0, ibs = 512, obs = 512;
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ssize_t n;
off_t seek = 0, skip = 0;
int oflag, ifd, ofd;
const char *infile = NULL, *outfile = NULL;
char *ibuf, *obuf;
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if (ENABLE_FEATURE_DD_SIGNAL_HANDLING) {
struct sigaction sa;
memset(&sa, 0, sizeof(sa));
sa.sa_handler = dd_output_status;
sa.sa_flags = SA_RESTART;
sigemptyset(&sa.sa_mask);
sigaction(SIGUSR1, &sa, 0);
}
for (n = 1; n < argc; n++) {
if (ENABLE_FEATURE_DD_IBS_OBS && !strncmp("ibs=", argv[n], 4)) {
ibs = bb_xparse_number(argv[n]+4, dd_suffixes);
flags |= twobufs_flag;
} else if (ENABLE_FEATURE_DD_IBS_OBS && !strncmp("obs=", argv[n], 4)) {
obs = bb_xparse_number(argv[n]+4, dd_suffixes);
flags |= twobufs_flag;
} else if (!strncmp("bs=", argv[n], 3))
ibs = obs = bb_xparse_number(argv[n]+3, dd_suffixes);
else if (!strncmp("count=", argv[n], 6))
count = bb_xparse_number(argv[n]+6, dd_suffixes);
else if (!strncmp("seek=", argv[n], 5))
seek = bb_xparse_number(argv[n]+5, dd_suffixes);
else if (!strncmp("skip=", argv[n], 5))
skip = bb_xparse_number(argv[n]+5, dd_suffixes);
else if (!strncmp("if=", argv[n], 3))
infile = argv[n]+3;
else if (!strncmp("of=", argv[n], 3))
outfile = argv[n]+3;
else if (ENABLE_FEATURE_DD_IBS_OBS && !strncmp("conv=", argv[n], 5)) {
ibuf = argv[n]+5;
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while (1) {
if (!strncmp("notrunc", ibuf, 7)) {
flags ^= trunc_flag;
ibuf += 7;
} else if (!strncmp("sync", ibuf, 4)) {
flags |= sync_flag;
ibuf += 4;
} else if (!strncmp("noerror", ibuf, 7)) {
flags |= noerror;
ibuf += 7;
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} else {
bb_error_msg_and_die(bb_msg_invalid_arg, argv[n]+5, "conv");
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}
if (ibuf[0] == '\0') break;
if (ibuf[0] == ',') ibuf++;
}
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} else
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bb_show_usage();
}
ibuf = xmalloc(ibs);
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if (flags & twobufs_flag)
obuf = xmalloc(obs);
else
obuf = ibuf;
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if (infile != NULL)
ifd = xopen(infile, O_RDONLY);
else {
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ifd = STDIN_FILENO;
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infile = bb_msg_standard_input;
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}
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if (outfile != NULL) {
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oflag = O_WRONLY | O_CREAT;
if (!seek && (flags & trunc_flag))
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oflag |= O_TRUNC;
ofd = xopen3(outfile, oflag, 0666);
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if (seek && (flags & trunc_flag)) {
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 {
ofd = STDOUT_FILENO;
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outfile = bb_msg_standard_output;
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}
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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)
bb_perror_msg_and_die("%s", 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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}
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while (in_full + in_part != count) {
if (flags & noerror) {
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/* Pre-zero the buffer when doing the noerror thing */
memset(ibuf, '\0', ibs);
}
n = safe_read(ifd, ibuf, ibs);
if (n == 0)
break;
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if (n < 0) {
if (flags & noerror) {
n = ibs;
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bb_perror_msg("%s", infile);
} else
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bb_perror_msg_and_die("%s", infile);
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}
if ((size_t)n == ibs)
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in_full++;
else {
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in_part++;
if (sync_flag) {
memset(ibuf + n, '\0', ibs - n);
n = ibs;
}
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}
if (flags & twobufs_flag) {
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) {
xwrite(ofd, obuf, obs);
out_full++;
oc = 0;
}
}
} else {
xwrite(ofd, ibuf, n);
if (n == ibs)
out_full++;
else
out_part++;
}
}
if (ENABLE_FEATURE_DD_IBS_OBS && oc) {
xwrite(ofd, obuf, oc);
out_part++;
}
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if (close (ifd) < 0) {
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bb_perror_msg_and_die("%s", infile);
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}
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if (close (ofd) < 0) {
die_outfile:
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bb_perror_msg_and_die("%s", outfile);
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}
dd_output_status(0);
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return EXIT_SUCCESS;
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}