mirror of
https://github.com/sheumann/hush.git
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338 lines
7.2 KiB
C
338 lines
7.2 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* Mini dd implementation for busybox
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*
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*
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* Copyright (C) 2000,2001 Matt Kraai
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*
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* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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*/
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#include <signal.h> /* For FEATURE_DD_SIGNAL_HANDLING */
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#include "libbb.h"
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/* This is a NOEXEC applet. Be very careful! */
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enum {
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ifd = STDIN_FILENO,
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ofd = STDOUT_FILENO,
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};
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static const struct suffix_mult dd_suffixes[] = {
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{ "c", 1 },
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{ "w", 2 },
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{ "b", 512 },
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{ "kD", 1000 },
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{ "k", 1024 },
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{ "K", 1024 }, /* compat with coreutils dd */
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{ "MD", 1000000 },
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{ "M", 1048576 },
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{ "GD", 1000000000 },
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{ "G", 1073741824 },
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{ }
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};
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struct globals {
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off_t out_full, out_part, in_full, in_part;
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};
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#define G (*(struct globals*)&bb_common_bufsiz1)
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/* We have to zero it out because of NOEXEC */
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#define INIT_G() memset(&G, 0, sizeof(G))
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static void dd_output_status(int ATTRIBUTE_UNUSED cur_signal)
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{
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/* Deliberately using %u, not %d */
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fprintf(stderr, "%"OFF_FMT"u+%"OFF_FMT"u records in\n"
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"%"OFF_FMT"u+%"OFF_FMT"u records out\n",
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G.in_full, G.in_part,
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G.out_full, G.out_part);
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}
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static ssize_t full_write_or_warn(const void *buf, size_t len,
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const char *const filename)
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{
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ssize_t n = full_write(ofd, buf, len);
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if (n < 0)
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bb_perror_msg("writing '%s'", filename);
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return n;
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}
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static bool write_and_stats(const void *buf, size_t len, size_t obs,
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const char *filename)
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{
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ssize_t n = full_write_or_warn(buf, len, filename);
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if (n < 0)
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return 1;
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if (n == obs)
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G.out_full++;
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else if (n) /* > 0 */
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G.out_part++;
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return 0;
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}
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#if ENABLE_LFS
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#define XATOU_SFX xatoull_sfx
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#else
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#define XATOU_SFX xatoul_sfx
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#endif
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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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{
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enum {
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FLAG_SYNC = 1 << 0,
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FLAG_NOERROR = 1 << 1,
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FLAG_NOTRUNC = 1 << 2,
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FLAG_TWOBUFS = 1 << 3,
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FLAG_COUNT = 1 << 4,
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};
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static const char keywords[] ALIGN1 =
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"bs=\0""count=\0""seek=\0""skip=\0""if=\0""of=\0"
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#if ENABLE_FEATURE_DD_IBS_OBS
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"ibs=\0""obs=\0""conv=\0""notrunc\0""sync\0""noerror\0"
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#endif
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;
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enum {
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OP_bs = 1,
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OP_count,
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OP_seek,
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OP_skip,
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OP_if,
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OP_of,
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#if ENABLE_FEATURE_DD_IBS_OBS
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OP_ibs,
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OP_obs,
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OP_conv,
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OP_conv_notrunc,
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OP_conv_sync,
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OP_conv_noerror,
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#endif
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};
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int exitcode = EXIT_FAILURE;
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size_t ibs = 512, obs = 512;
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ssize_t n, w;
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char *ibuf, *obuf;
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/* And these are all zeroed at once! */
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struct {
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int flags;
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size_t oc;
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off_t count;
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off_t seek, skip;
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const char *infile, *outfile;
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#if ENABLE_FEATURE_DD_SIGNAL_HANDLING
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struct sigaction sigact;
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#endif
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} Z;
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#define flags (Z.flags )
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#define oc (Z.oc )
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#define count (Z.count )
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#define seek (Z.seek )
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#define skip (Z.skip )
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#define infile (Z.infile )
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#define outfile (Z.outfile)
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#define sigact (Z.sigact )
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memset(&Z, 0, sizeof(Z));
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INIT_G();
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//fflush(NULL); - is this needed because of NOEXEC?
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#if ENABLE_FEATURE_DD_SIGNAL_HANDLING
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sigact.sa_handler = dd_output_status;
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sigact.sa_flags = SA_RESTART;
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/*sigemptyset(&sigact.sa_mask); - memset did it */
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sigaction(SIGUSR1, &sigact, NULL);
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#endif
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for (n = 1; n < argc; n++) {
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smalluint key_len;
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smalluint what;
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char *key;
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char *arg = argv[n];
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//XXX:FIXME: we reject plain "dd --" This would cost ~20 bytes, so..
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//if (*arg == '-' && *++arg == '-' && !*++arg) continue;
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key = strstr(arg, "=");
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if (key == NULL)
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bb_show_usage();
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key_len = key - arg + 1;
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key = xstrndup(arg, key_len);
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what = index_in_strings(keywords, key) + 1;
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if (ENABLE_FEATURE_CLEAN_UP)
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free(key);
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if (what == 0)
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bb_show_usage();
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arg += key_len;
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#if ENABLE_FEATURE_DD_IBS_OBS
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if (what == OP_ibs) {
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/* Must fit into positive ssize_t */
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ibs = xatoul_range_sfx(arg, 1, ((size_t)-1L)/2, dd_suffixes);
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continue;
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}
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if (what == OP_obs) {
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obs = xatoul_range_sfx(arg, 1, ((size_t)-1L)/2, dd_suffixes);
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continue;
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}
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if (what == OP_conv) {
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while (1) {
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/* find ',', replace them with NUL so we can use arg for
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* index_in_strings() without copying.
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* We rely on arg being non-null, else strchr would fault.
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*/
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key = strchr(arg, ',');
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if (key)
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*key = '\0';
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what = index_in_strings(keywords, arg) + 1;
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if (what < OP_conv_notrunc)
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bb_error_msg_and_die(bb_msg_invalid_arg, arg, "conv");
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if (what == OP_conv_notrunc)
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flags |= FLAG_NOTRUNC;
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if (what == OP_conv_sync)
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flags |= FLAG_SYNC;
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if (what == OP_conv_noerror)
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flags |= FLAG_NOERROR;
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if (!key) /* no ',' left, so this was the last specifier */
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break;
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arg = key + 1; /* skip this keyword and ',' */
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}
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continue;
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}
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#endif
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if (what == OP_bs) {
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ibs = obs = xatoul_range_sfx(arg, 1, ((size_t)-1L)/2, dd_suffixes);
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continue;
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}
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/* These can be large: */
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if (what == OP_count) {
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flags |= FLAG_COUNT;
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count = XATOU_SFX(arg, dd_suffixes);
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continue;
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}
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if (what == OP_seek) {
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seek = XATOU_SFX(arg, dd_suffixes);
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continue;
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}
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if (what == OP_skip) {
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skip = XATOU_SFX(arg, dd_suffixes);
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continue;
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}
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if (what == OP_if) {
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infile = arg;
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continue;
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}
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if (what == OP_of)
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outfile = arg;
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}
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//XXX:FIXME for huge ibs or obs, malloc'ing them isn't the brightest idea ever
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ibuf = obuf = xmalloc(ibs);
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if (ibs != obs) {
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flags |= FLAG_TWOBUFS;
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obuf = xmalloc(obs);
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}
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if (infile != NULL)
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xmove_fd(xopen(infile, O_RDONLY), ifd);
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else {
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infile = bb_msg_standard_input;
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}
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if (outfile != NULL) {
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int oflag = O_WRONLY | O_CREAT;
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if (!seek && !(flags & FLAG_NOTRUNC))
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oflag |= O_TRUNC;
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xmove_fd(xopen(outfile, oflag), ofd);
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if (seek && !(flags & FLAG_NOTRUNC)) {
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if (ftruncate(ofd, seek * obs) < 0) {
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struct stat st;
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if (fstat(ofd, &st) < 0 || S_ISREG(st.st_mode) ||
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S_ISDIR(st.st_mode))
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goto die_outfile;
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}
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}
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} else {
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outfile = bb_msg_standard_output;
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}
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if (skip) {
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if (lseek(ifd, skip * ibs, SEEK_CUR) < 0) {
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while (skip-- > 0) {
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n = safe_read(ifd, ibuf, ibs);
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if (n < 0)
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goto die_infile;
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if (n == 0)
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break;
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}
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}
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}
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if (seek) {
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if (lseek(ofd, seek * obs, SEEK_CUR) < 0)
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goto die_outfile;
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}
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while (!(flags & FLAG_COUNT) || (G.in_full + G.in_part != count)) {
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if (flags & FLAG_NOERROR) /* Pre-zero the buffer if conv=noerror */
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memset(ibuf, 0, ibs);
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n = safe_read(ifd, ibuf, ibs);
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if (n == 0)
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break;
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if (n < 0) {
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if (!(flags & FLAG_NOERROR))
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goto die_infile;
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n = ibs;
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bb_simple_perror_msg(infile);
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}
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if ((size_t)n == ibs)
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G.in_full++;
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else {
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G.in_part++;
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if (flags & FLAG_SYNC) {
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memset(ibuf + n, '\0', ibs - n);
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n = ibs;
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}
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}
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if (flags & FLAG_TWOBUFS) {
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char *tmp = ibuf;
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while (n) {
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size_t d = obs - oc;
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if (d > n)
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d = n;
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memcpy(obuf + oc, tmp, d);
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n -= d;
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tmp += d;
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oc += d;
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if (oc == obs) {
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if (write_and_stats(obuf, obs, obs, outfile))
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goto out_status;
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oc = 0;
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}
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}
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} else if (write_and_stats(ibuf, n, obs, outfile))
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goto out_status;
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}
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if (ENABLE_FEATURE_DD_IBS_OBS && oc) {
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w = full_write_or_warn(obuf, oc, outfile);
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if (w < 0) goto out_status;
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if (w > 0)
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G.out_part++;
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}
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if (close(ifd) < 0) {
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die_infile:
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bb_simple_perror_msg_and_die(infile);
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}
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if (close(ofd) < 0) {
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die_outfile:
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bb_simple_perror_msg_and_die(outfile);
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}
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exitcode = EXIT_SUCCESS;
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out_status:
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dd_output_status(0);
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return exitcode;
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}
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