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busybox: backport dd support for iflag=count_bytes

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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
2021-12-16 12:36:16 +01:00
parent 7e4485fd5b
commit b6ed2641df
1 changed files with 140 additions and 0 deletions
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140
package/utils/busybox/patches/001-dd-support-iflag-count_bytes.patch Normal file
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@@ -0,0 +1,140 @@
From 4eb46e1be6d88eaf077252ce93127ebf00aa8ef2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
Date: Wed, 24 Mar 2021 16:01:42 +0100
Subject: [PATCH] dd: support iflag=count_bytes
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
It allows passing amount of bytes in the count=
function old new delta
packed_usage 33599 33617 +18
static.iflag_words 29 41 +12
dd_main 1601 1607 +6
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 3/0 up/down: 36/0) Total: 36 bytes
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
---
coreutils/dd.c | 50 ++++++++++++++++++++++++-------------
testsuite/dd/dd-count-bytes | 1 +
2 files changed, 33 insertions(+), 18 deletions(-)
create mode 100644 testsuite/dd/dd-count-bytes
--- a/coreutils/dd.c
+++ b/coreutils/dd.c
@@ -59,7 +59,7 @@
//usage: "[if=FILE] [of=FILE] [" IF_FEATURE_DD_IBS_OBS("ibs=N obs=N/") "bs=N] [count=N] [skip=N] [seek=N]\n"
//usage: IF_FEATURE_DD_IBS_OBS(
//usage: " [conv=notrunc|noerror|sync|fsync]\n"
-//usage: " [iflag=skip_bytes|fullblock|direct] [oflag=seek_bytes|append|direct]"
+//usage: " [iflag=skip_bytes|count_bytes|fullblock|direct] [oflag=seek_bytes|append|direct]"
//usage: )
//usage:#define dd_full_usage "\n\n"
//usage: "Copy a file with converting and formatting\n"
@@ -82,6 +82,7 @@
//usage: "\n conv=fsync Physically write data out before finishing"
//usage: "\n conv=swab Swap every pair of bytes"
//usage: "\n iflag=skip_bytes skip=N is in bytes"
+//usage: "\n iflag=count_bytes count=N is in bytes"
//usage: "\n oflag=seek_bytes seek=N is in bytes"
//usage: "\n iflag=direct O_DIRECT input"
//usage: "\n oflag=direct O_DIRECT output"
@@ -136,21 +137,22 @@ enum {
FLAG_SWAB = (1 << 4) * ENABLE_FEATURE_DD_IBS_OBS,
/* end of conv flags */
/* start of input flags */
- FLAG_IFLAG_SHIFT = 5,
- FLAG_SKIP_BYTES = (1 << 5) * ENABLE_FEATURE_DD_IBS_OBS,
- FLAG_FULLBLOCK = (1 << 6) * ENABLE_FEATURE_DD_IBS_OBS,
- FLAG_IDIRECT = (1 << 7) * ENABLE_FEATURE_DD_IBS_OBS,
+ FLAG_IFLAG_SHIFT = 5,
+ FLAG_SKIP_BYTES = (1 << 5) * ENABLE_FEATURE_DD_IBS_OBS,
+ FLAG_COUNT_BYTES = (1 << 6) * ENABLE_FEATURE_DD_IBS_OBS,
+ FLAG_FULLBLOCK = (1 << 7) * ENABLE_FEATURE_DD_IBS_OBS,
+ FLAG_IDIRECT = (1 << 8) * ENABLE_FEATURE_DD_IBS_OBS,
/* end of input flags */
/* start of output flags */
- FLAG_OFLAG_SHIFT = 8,
- FLAG_SEEK_BYTES = (1 << 8) * ENABLE_FEATURE_DD_IBS_OBS,
- FLAG_APPEND = (1 << 9) * ENABLE_FEATURE_DD_IBS_OBS,
- FLAG_ODIRECT = (1 << 10) * ENABLE_FEATURE_DD_IBS_OBS,
+ FLAG_OFLAG_SHIFT = 9,
+ FLAG_SEEK_BYTES = (1 << 9) * ENABLE_FEATURE_DD_IBS_OBS,
+ FLAG_APPEND = (1 << 10) * ENABLE_FEATURE_DD_IBS_OBS,
+ FLAG_ODIRECT = (1 << 11) * ENABLE_FEATURE_DD_IBS_OBS,
/* end of output flags */
- FLAG_TWOBUFS = (1 << 11) * ENABLE_FEATURE_DD_IBS_OBS,
- FLAG_COUNT = 1 << 12,
- FLAG_STATUS_NONE = 1 << 13,
- FLAG_STATUS_NOXFER = 1 << 14,
+ FLAG_TWOBUFS = (1 << 12) * ENABLE_FEATURE_DD_IBS_OBS,
+ FLAG_COUNT = 1 << 13,
+ FLAG_STATUS_NONE = 1 << 14,
+ FLAG_STATUS_NOXFER = 1 << 15,
};
static void dd_output_status(int UNUSED_PARAM cur_signal)
@@ -175,8 +177,9 @@ static void dd_output_status(int UNUSED_
//So far we react to it (we print the stats),
//status=none only suppresses final, non-USR1 generated status message.
# endif
- fprintf(stderr, "%llu bytes (%sB) copied, ",
- G.total_bytes,
+ fprintf(stderr, /*G.total_bytes < 1024
+ ? "%llu bytes copied, " : */ "%llu bytes (%sB) copied, "
+ , G.total_bytes,
/* show fractional digit, use suffixes */
make_human_readable_str(G.total_bytes, 1, 0)
);
@@ -317,7 +320,7 @@ int dd_main(int argc UNUSED_PARAM, char
static const char conv_words[] ALIGN1 =
"notrunc\0""sync\0""noerror\0""fsync\0""swab\0";
static const char iflag_words[] ALIGN1 =
- "skip_bytes\0""fullblock\0""direct\0";
+ "skip_bytes\0""count_bytes\0""fullblock\0""direct\0";
static const char oflag_words[] ALIGN1 =
"seek_bytes\0append\0""direct\0";
#endif
@@ -359,6 +362,7 @@ int dd_main(int argc UNUSED_PARAM, char
/* Partially implemented: */
//swab swap every pair of input bytes: will abort on non-even reads
OP_iflag_skip_bytes,
+ OP_iflag_count_bytes,
OP_iflag_fullblock,
OP_iflag_direct,
OP_oflag_seek_bytes,
@@ -551,8 +555,17 @@ int dd_main(int argc UNUSED_PARAM, char
goto die_outfile;
}
- while (!(G.flags & FLAG_COUNT) || (G.in_full + G.in_part != count)) {
- ssize_t n = dd_read(ibuf, ibs);
+ while (1) {
+ ssize_t n = ibs;
+
+ if (G.flags & FLAG_COUNT) {
+ if (count == 0)
+ break;
+ if ((G.flags & FLAG_COUNT_BYTES) && count < ibs)
+ n = count;
+ }
+
+ n = dd_read(ibuf, n);
if (n == 0)
break;
if (n < 0) {
@@ -587,6 +600,7 @@ int dd_main(int argc UNUSED_PARAM, char
p16++;
}
}
+ count -= (G.flags & FLAG_COUNT_BYTES) ? n : 1;
if ((size_t)n == ibs)
G.in_full++;
else {
--- /dev/null
+++ b/testsuite/dd/dd-count-bytes
@@ -0,0 +1 @@
+test "$(echo I WANT | busybox dd count=3 iflag=count_bytes 2>/dev/null)" = "I W"