[PATCH] dd: support iflag=count_bytes
Denys Vlasenko
vda.linux at googlemail.com
Tue Apr 13 19:40:16 UTC 2021
Applied, thanks
On Wed, Mar 24, 2021 at 4:02 PM Rafał Miłecki <zajec5 at gmail.com> wrote:
>
> From: Rafał Miłecki <rafal at milecki.pl>
>
> It allows passing amount of bytes in the count=
>
> Signed-off-by: Rafał Miłecki <rafal at milecki.pl>
> ---
> coreutils/dd.c | 54 +++++++++++++++++++++++++++----------
> testsuite/dd/dd-count-bytes | 1 +
> 2 files changed, 41 insertions(+), 14 deletions(-)
> create mode 100644 testsuite/dd/dd-count-bytes
>
> diff --git a/coreutils/dd.c b/coreutils/dd.c
> index 24d7f0b84..22600f510 100644
> --- 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"
> @@ -138,19 +139,20 @@ enum {
> /* 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_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)
> @@ -317,7 +319,7 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
> 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 +361,7 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
> /* 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,
> @@ -366,6 +369,7 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
> #endif
> };
> smallint exitcode = EXIT_FAILURE;
> + ssize_t max_in_full = -1;
> int i;
> size_t ibs = 512;
> char *ibuf;
> @@ -551,8 +555,20 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
> goto die_outfile;
> }
>
> - while (!(G.flags & FLAG_COUNT) || (G.in_full + G.in_part != count)) {
> - ssize_t n = dd_read(ibuf, ibs);
> + if (G.flags & FLAG_COUNT)
> + max_in_full = (G.flags & FLAG_COUNT_BYTES) ? count / ibs : count;
> +
> + while (1) {
> + size_t to_read;
> + ssize_t n;
> +
> + to_read = ibs;
> + if (G.flags & FLAG_COUNT &&
> + G.flags & FLAG_COUNT_BYTES &&
> + G.in_full == max_in_full)
> + to_read = count % ibs;
> +
> + n = dd_read(ibuf, to_read);
> if (n == 0)
> break;
> if (n < 0) {
> @@ -619,6 +635,16 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
> if (write_and_stats(ibuf, n, obs, outfile))
> goto out_status;
> }
> +
> + if (G.flags & FLAG_COUNT) {
> + if (G.flags & FLAG_COUNT_BYTES) {
> + if ((G.in_full + G.in_part) * ibs >= count)
> + break;
> + } else {
> + if (G.in_full + G.in_part == count)
> + break;
> + }
> + }
> }
>
> if (G.flags & FLAG_FSYNC) {
> diff --git a/testsuite/dd/dd-count-bytes b/testsuite/dd/dd-count-bytes
> new file mode 100644
> index 000000000..0730cba5e
> --- /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"
> --
> 2.26.2
>
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