567 lines
15 KiB
C
567 lines
15 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 source tree.
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*/
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//config:config DD
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//config: bool "dd"
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//config: default y
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//config: help
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//config: dd copies a file (from standard input to standard output,
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//config: by default) using specific input and output blocksizes,
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//config: while optionally performing conversions on it.
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//config:
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//config:config FEATURE_DD_SIGNAL_HANDLING
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//config: bool "Enable signal handling for status reporting"
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//config: default y
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//config: depends on DD
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//config: help
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//config: Sending a SIGUSR1 signal to a running `dd' process makes it
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//config: print to standard error the number of records read and written
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//config: so far, then to resume copying.
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//config:
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//config: $ dd if=/dev/zero of=/dev/null &
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//config: $ pid=$!; kill -USR1 $pid; sleep 1; kill $pid
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//config: 10899206+0 records in
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//config: 10899206+0 records out
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//config:
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//config:config FEATURE_DD_THIRD_STATUS_LINE
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//config: bool "Enable the third status line upon signal"
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//config: default y
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//config: depends on DD && FEATURE_DD_SIGNAL_HANDLING
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//config: help
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//config: Displays a coreutils-like third status line with transferred bytes,
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//config: elapsed time and speed.
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//config:
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//config:config FEATURE_DD_IBS_OBS
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//config: bool "Enable ibs, obs and conv options"
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//config: default y
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//config: depends on DD
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//config: help
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//config: Enables support for writing a certain number of bytes in and out,
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//config: at a time, and performing conversions on the data stream.
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//config:
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//config:config FEATURE_DD_STATUS
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//config: bool "Enable status display options"
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//config: default y
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//config: depends on DD
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//config: help
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//config: Enables support for status=noxfer/none option.
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//usage:#define dd_trivial_usage
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//usage: "[if=FILE] [of=FILE] " IF_FEATURE_DD_IBS_OBS("[ibs=N] [obs=N] ") "[bs=N] [count=N] [skip=N]\n"
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//usage: " [seek=N]" IF_FEATURE_DD_IBS_OBS(" [conv=notrunc|noerror|sync|fsync] [iflag=skip_bytes]")
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//usage:#define dd_full_usage "\n\n"
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//usage: "Copy a file with converting and formatting\n"
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//usage: "\n if=FILE Read from FILE instead of stdin"
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//usage: "\n of=FILE Write to FILE instead of stdout"
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//usage: "\n bs=N Read and write N bytes at a time"
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//usage: IF_FEATURE_DD_IBS_OBS(
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//usage: "\n ibs=N Read N bytes at a time"
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//usage: )
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//usage: IF_FEATURE_DD_IBS_OBS(
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//usage: "\n obs=N Write N bytes at a time"
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//usage: )
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//usage: "\n count=N Copy only N input blocks"
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//usage: "\n skip=N Skip N input blocks"
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//usage: "\n seek=N Skip N output blocks"
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//usage: IF_FEATURE_DD_IBS_OBS(
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//usage: "\n conv=notrunc Don't truncate output file"
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//usage: "\n conv=noerror Continue after read errors"
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//usage: "\n conv=sync Pad blocks with zeros"
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//usage: "\n conv=fsync Physically write data out before finishing"
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//usage: "\n conv=swab Swap every pair of bytes"
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//usage: "\n iflag=skip_bytes skip=N is in bytes"
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//usage: )
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//usage: IF_FEATURE_DD_STATUS(
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//usage: "\n status=noxfer Suppress rate output"
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//usage: "\n status=none Suppress all output"
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//usage: )
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//usage: "\n"
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//usage: "\nN may be suffixed by c (1), w (2), b (512), kB (1000), k (1024), MB, M, GB, G"
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//usage:
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//usage:#define dd_example_usage
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//usage: "$ dd if=/dev/zero of=/dev/ram1 bs=1M count=4\n"
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//usage: "4+0 records in\n"
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//usage: "4+0 records out\n"
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#include "libbb.h"
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#include "common_bufsiz.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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struct globals {
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off_t out_full, out_part, in_full, in_part;
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#if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
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unsigned long long total_bytes;
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unsigned long long begin_time_us;
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#endif
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int flags;
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} FIX_ALIASING;
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#define G (*(struct globals*)bb_common_bufsiz1)
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#define INIT_G() do { \
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setup_common_bufsiz(); \
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/* we have to zero it out because of NOEXEC */ \
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memset(&G, 0, sizeof(G)); \
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} while (0)
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enum {
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/* Must be in the same order as OP_conv_XXX! */
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/* (see "flags |= (1 << what)" below) */
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FLAG_NOTRUNC = (1 << 0) * ENABLE_FEATURE_DD_IBS_OBS,
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FLAG_SYNC = (1 << 1) * ENABLE_FEATURE_DD_IBS_OBS,
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FLAG_NOERROR = (1 << 2) * ENABLE_FEATURE_DD_IBS_OBS,
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FLAG_FSYNC = (1 << 3) * ENABLE_FEATURE_DD_IBS_OBS,
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FLAG_SWAB = (1 << 4) * ENABLE_FEATURE_DD_IBS_OBS,
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/* end of conv flags */
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/* start of input flags */
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FLAG_IFLAG_SHIFT = 5,
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FLAG_SKIP_BYTES = (1 << 5) * ENABLE_FEATURE_DD_IBS_OBS,
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/* end of input flags */
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FLAG_TWOBUFS = (1 << 6) * ENABLE_FEATURE_DD_IBS_OBS,
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FLAG_COUNT = 1 << 7,
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FLAG_STATUS = 1 << 8,
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FLAG_STATUS_NONE = 1 << 9,
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FLAG_STATUS_NOXFER = 1 << 10,
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};
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static void dd_output_status(int UNUSED_PARAM cur_signal)
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{
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#if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
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double seconds;
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unsigned long long bytes_sec;
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unsigned long long now_us = monotonic_us(); /* before fprintf */
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#endif
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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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#if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
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# if ENABLE_FEATURE_DD_STATUS
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if (G.flags & FLAG_STATUS_NOXFER) /* status=noxfer active? */
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return;
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//TODO: should status=none make dd stop reacting to USR1 entirely?
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//So far we react to it (we print the stats),
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//status=none only suppresses final, non-USR1 generated status message.
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# endif
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fprintf(stderr, "%llu bytes (%sB) copied, ",
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G.total_bytes,
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/* show fractional digit, use suffixes */
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make_human_readable_str(G.total_bytes, 1, 0)
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);
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/* Corner cases:
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* ./busybox dd </dev/null >/dev/null
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* ./busybox dd bs=1M count=2000 </dev/zero >/dev/null
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* (echo DONE) | ./busybox dd >/dev/null
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* (sleep 1; echo DONE) | ./busybox dd >/dev/null
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*/
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seconds = (now_us - G.begin_time_us) / 1000000.0;
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bytes_sec = G.total_bytes / seconds;
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fprintf(stderr, "%f seconds, %sB/s\n",
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seconds,
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/* show fractional digit, use suffixes */
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make_human_readable_str(bytes_sec, 1, 0)
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);
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#endif
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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 ((size_t)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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#if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
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G.total_bytes += n;
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#endif
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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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#if ENABLE_FEATURE_DD_IBS_OBS
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static int parse_comma_flags(char *val, const char *words, const char *error_in)
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{
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int flags = 0;
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while (1) {
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int n;
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char *arg;
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/* find ',', replace them with NUL so we can use val for
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* index_in_strings() without copying.
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* We rely on val being non-null, else strchr would fault.
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*/
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arg = strchr(val, ',');
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if (arg)
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*arg = '\0';
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n = index_in_strings(words, val);
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if (n < 0)
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bb_error_msg_and_die(bb_msg_invalid_arg_to, val, error_in);
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flags |= (1 << n);
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if (!arg) /* no ',' left, so this was the last specifier */
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break;
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*arg = ','; /* to preserve ps listing */
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val = arg + 1; /* skip this keyword and ',' */
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}
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return flags;
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}
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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 UNUSED_PARAM, char **argv)
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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"IF_FEATURE_DD_STATUS("status\0")
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#if ENABLE_FEATURE_DD_IBS_OBS
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"ibs\0""obs\0""conv\0""iflag\0"
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#endif
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;
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#if ENABLE_FEATURE_DD_IBS_OBS
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static const char conv_words[] ALIGN1 =
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"notrunc\0""sync\0""noerror\0""fsync\0""swab\0";
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static const char iflag_words[] ALIGN1 =
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"skip_bytes\0";
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#endif
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#if ENABLE_FEATURE_DD_STATUS
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static const char status_words[] ALIGN1 =
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"none\0""noxfer\0";
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#endif
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enum {
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OP_bs = 0,
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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_FEATURE_DD_STATUS(OP_status,)
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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_iflag,
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/* Must be in the same order as FLAG_XXX! */
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OP_conv_notrunc = 0,
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OP_conv_sync,
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OP_conv_noerror,
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OP_conv_fsync,
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OP_conv_swab,
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/* Unimplemented conv=XXX: */
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//nocreat do not create the output file
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//excl fail if the output file already exists
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//fdatasync physically write output file data before finishing
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//lcase change upper case to lower case
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//ucase change lower case to upper case
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//block pad newline-terminated records with spaces to cbs-size
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//unblock replace trailing spaces in cbs-size records with newline
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//ascii from EBCDIC to ASCII
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//ebcdic from ASCII to EBCDIC
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//ibm from ASCII to alternate EBCDIC
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/* Partially implemented: */
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//swab swap every pair of input bytes: will abort on non-even reads
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OP_iflag_skip_bytes,
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#endif
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};
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smallint exitcode = EXIT_FAILURE;
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int i;
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size_t ibs = 512;
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char *ibuf;
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#if ENABLE_FEATURE_DD_IBS_OBS
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size_t obs = 512;
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char *obuf;
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#else
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# define obs ibs
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# define obuf ibuf
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#endif
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/* These are all zeroed at once! */
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struct {
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size_t oc;
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ssize_t prev_read_size; /* for detecting swab failure */
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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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} Z;
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#define oc (Z.oc )
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#define prev_read_size (Z.prev_read_size)
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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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memset(&Z, 0, sizeof(Z));
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INIT_G();
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//fflush_all(); - is this needed because of NOEXEC?
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for (i = 1; argv[i]; i++) {
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int what;
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char *val;
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char *arg = argv[i];
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#if ENABLE_DESKTOP
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/* "dd --". NB: coreutils 6.9 will complain if they see
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* more than one of them. We wouldn't. */
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if (arg[0] == '-' && arg[1] == '-' && arg[2] == '\0')
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continue;
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#endif
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val = strchr(arg, '=');
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if (val == NULL)
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bb_show_usage();
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*val = '\0';
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what = index_in_strings(keywords, arg);
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if (what < 0)
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bb_show_usage();
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/* *val = '='; - to preserve ps listing? */
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val++;
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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(val, 1, ((size_t)-1L)/2, cwbkMG_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(val, 1, ((size_t)-1L)/2, cwbkMG_suffixes);
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/*continue;*/
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}
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if (what == OP_conv) {
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G.flags |= parse_comma_flags(val, conv_words, "conv");
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/*continue;*/
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}
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if (what == OP_iflag) {
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G.flags |= parse_comma_flags(val, iflag_words, "iflag") << FLAG_IFLAG_SHIFT;
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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 = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, cwbkMG_suffixes);
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obs = ibs;
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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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G.flags |= FLAG_COUNT;
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count = XATOU_SFX(val, cwbkMG_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(val, cwbkMG_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(val, cwbkMG_suffixes);
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/*continue;*/
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}
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if (what == OP_if) {
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infile = val;
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/*continue;*/
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}
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if (what == OP_of) {
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outfile = val;
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/*continue;*/
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}
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#if ENABLE_FEATURE_DD_STATUS
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if (what == OP_status) {
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int n;
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n = index_in_strings(status_words, val);
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if (n < 0)
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bb_error_msg_and_die(bb_msg_invalid_arg_to, val, "status");
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G.flags |= FLAG_STATUS << n;
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/*continue;*/
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}
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#endif
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} /* end of "for (argv[i])" */
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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 = xmalloc(ibs);
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obuf = ibuf;
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#if ENABLE_FEATURE_DD_IBS_OBS
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if (ibs != obs) {
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G.flags |= FLAG_TWOBUFS;
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obuf = xmalloc(obs);
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}
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#endif
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#if ENABLE_FEATURE_DD_SIGNAL_HANDLING
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signal_SA_RESTART_empty_mask(SIGUSR1, dd_output_status);
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#endif
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#if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
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G.begin_time_us = monotonic_us();
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#endif
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if (infile) {
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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) {
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int oflag = O_WRONLY | O_CREAT;
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if (!seek && !(G.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 && !(G.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
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|| S_ISREG(st.st_mode)
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|| S_ISDIR(st.st_mode)
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) {
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goto die_outfile;
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}
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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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size_t blocksz = (G.flags & FLAG_SKIP_BYTES) ? 1 : ibs;
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if (lseek(ifd, skip * blocksz, SEEK_CUR) < 0) {
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do {
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ssize_t n = safe_read(ifd, ibuf, blocksz);
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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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} while (--skip != 0);
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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 (!(G.flags & FLAG_COUNT) || (G.in_full + G.in_part != count)) {
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ssize_t n;
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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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/* "Bad block" */
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if (!(G.flags & FLAG_NOERROR))
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goto die_infile;
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|
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;
|
|
}
|