busybox: backport dd support for iflag=count_bytes
It's very useful flag for handling various formats in sysupgrade. This commit comes from the 1.34.0 release. Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
This commit is contained in:
Rafał Miłecki
parent
7e4485fd5b
commit
b6ed2641df
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@ -0,0 +1,140 @@
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From 4eb46e1be6d88eaf077252ce93127ebf00aa8ef2 Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
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Date: Wed, 24 Mar 2021 16:01:42 +0100
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Subject: [PATCH] dd: support iflag=count_bytes
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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It allows passing amount of bytes in the count=
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function old new delta
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packed_usage 33599 33617 +18
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static.iflag_words 29 41 +12
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dd_main 1601 1607 +6
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------------------------------------------------------------------------------
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(add/remove: 0/0 grow/shrink: 3/0 up/down: 36/0) Total: 36 bytes
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Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
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Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
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---
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coreutils/dd.c | 50 ++++++++++++++++++++++++-------------
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testsuite/dd/dd-count-bytes | 1 +
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2 files changed, 33 insertions(+), 18 deletions(-)
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create mode 100644 testsuite/dd/dd-count-bytes
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--- a/coreutils/dd.c
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+++ b/coreutils/dd.c
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@@ -59,7 +59,7 @@
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//usage: "[if=FILE] [of=FILE] [" IF_FEATURE_DD_IBS_OBS("ibs=N obs=N/") "bs=N] [count=N] [skip=N] [seek=N]\n"
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//usage: IF_FEATURE_DD_IBS_OBS(
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//usage: " [conv=notrunc|noerror|sync|fsync]\n"
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-//usage: " [iflag=skip_bytes|fullblock|direct] [oflag=seek_bytes|append|direct]"
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+//usage: " [iflag=skip_bytes|count_bytes|fullblock|direct] [oflag=seek_bytes|append|direct]"
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//usage: )
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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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@@ -82,6 +82,7 @@
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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: "\n iflag=count_bytes count=N is in bytes"
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//usage: "\n oflag=seek_bytes seek=N is in bytes"
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//usage: "\n iflag=direct O_DIRECT input"
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//usage: "\n oflag=direct O_DIRECT output"
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@@ -136,21 +137,22 @@ enum {
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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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- FLAG_FULLBLOCK = (1 << 6) * ENABLE_FEATURE_DD_IBS_OBS,
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- FLAG_IDIRECT = (1 << 7) * ENABLE_FEATURE_DD_IBS_OBS,
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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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+ FLAG_COUNT_BYTES = (1 << 6) * ENABLE_FEATURE_DD_IBS_OBS,
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+ FLAG_FULLBLOCK = (1 << 7) * ENABLE_FEATURE_DD_IBS_OBS,
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+ FLAG_IDIRECT = (1 << 8) * ENABLE_FEATURE_DD_IBS_OBS,
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/* end of input flags */
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/* start of output flags */
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- FLAG_OFLAG_SHIFT = 8,
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- FLAG_SEEK_BYTES = (1 << 8) * ENABLE_FEATURE_DD_IBS_OBS,
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- FLAG_APPEND = (1 << 9) * ENABLE_FEATURE_DD_IBS_OBS,
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- FLAG_ODIRECT = (1 << 10) * ENABLE_FEATURE_DD_IBS_OBS,
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+ FLAG_OFLAG_SHIFT = 9,
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+ FLAG_SEEK_BYTES = (1 << 9) * ENABLE_FEATURE_DD_IBS_OBS,
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+ FLAG_APPEND = (1 << 10) * ENABLE_FEATURE_DD_IBS_OBS,
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+ FLAG_ODIRECT = (1 << 11) * ENABLE_FEATURE_DD_IBS_OBS,
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/* end of output flags */
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- FLAG_TWOBUFS = (1 << 11) * ENABLE_FEATURE_DD_IBS_OBS,
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- FLAG_COUNT = 1 << 12,
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- FLAG_STATUS_NONE = 1 << 13,
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- FLAG_STATUS_NOXFER = 1 << 14,
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+ FLAG_TWOBUFS = (1 << 12) * ENABLE_FEATURE_DD_IBS_OBS,
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+ FLAG_COUNT = 1 << 13,
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+ FLAG_STATUS_NONE = 1 << 14,
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+ FLAG_STATUS_NOXFER = 1 << 15,
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};
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static void dd_output_status(int UNUSED_PARAM cur_signal)
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@@ -175,8 +177,9 @@ static void dd_output_status(int UNUSED_
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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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+ fprintf(stderr, /*G.total_bytes < 1024
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+ ? "%llu bytes copied, " : */ "%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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@@ -317,7 +320,7 @@ int dd_main(int argc UNUSED_PARAM, char
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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""fullblock\0""direct\0";
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+ "skip_bytes\0""count_bytes\0""fullblock\0""direct\0";
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static const char oflag_words[] ALIGN1 =
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"seek_bytes\0append\0""direct\0";
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#endif
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@@ -359,6 +362,7 @@ int dd_main(int argc UNUSED_PARAM, char
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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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+ OP_iflag_count_bytes,
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OP_iflag_fullblock,
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OP_iflag_direct,
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OP_oflag_seek_bytes,
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@@ -551,8 +555,17 @@ int dd_main(int argc UNUSED_PARAM, char
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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 = dd_read(ibuf, ibs);
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+ while (1) {
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+ ssize_t n = ibs;
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+
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+ if (G.flags & FLAG_COUNT) {
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+ if (count == 0)
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+ break;
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+ if ((G.flags & FLAG_COUNT_BYTES) && count < ibs)
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+ n = count;
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+ }
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+
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+ n = dd_read(ibuf, n);
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if (n == 0)
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break;
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if (n < 0) {
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@@ -587,6 +600,7 @@ int dd_main(int argc UNUSED_PARAM, char
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p16++;
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}
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}
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+ count -= (G.flags & FLAG_COUNT_BYTES) ? n : 1;
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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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--- /dev/null
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+++ b/testsuite/dd/dd-count-bytes
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@@ -0,0 +1 @@
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+test "$(echo I WANT | busybox dd count=3 iflag=count_bytes 2>/dev/null)" = "I W"
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