dd: support iflag=skip_bytes
It allows specifying amount of bytes directly (not only amount of
blocks) is also supported by GNU's Coreutils.
function old new delta
parse_comma_flags - 93 +93
static.iflag_words - 12 +12
dd_main 1569 1580 +11
packed_usage 30591 30600 +9
------------------------------------------------------------------------------
(add/remove: 2/0 grow/shrink: 2/0 up/down: 125/0) Total: 125 bytes
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/coreutils/dd.c b/coreutils/dd.c
index 6a5288d..0c0ea07 100644
--- a/coreutils/dd.c
+++ b/coreutils/dd.c
@@ -55,7 +55,7 @@
//usage:#define dd_trivial_usage
//usage: "[if=FILE] [of=FILE] " IF_FEATURE_DD_IBS_OBS("[ibs=N] [obs=N] ") "[bs=N] [count=N] [skip=N]\n"
-//usage: " [seek=N]" IF_FEATURE_DD_IBS_OBS(" [conv=notrunc|noerror|sync|fsync]")
+//usage: " [seek=N]" IF_FEATURE_DD_IBS_OBS(" [conv=notrunc|noerror|sync|fsync] [iflag=skip_bytes]")
//usage:#define dd_full_usage "\n\n"
//usage: "Copy a file with converting and formatting\n"
//usage: "\n if=FILE Read from FILE instead of stdin"
@@ -76,6 +76,7 @@
//usage: "\n conv=sync Pad blocks with zeros"
//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: )
//usage: IF_FEATURE_DD_STATUS(
//usage: "\n status=noxfer Suppress rate output"
@@ -122,11 +123,15 @@
FLAG_FSYNC = (1 << 3) * ENABLE_FEATURE_DD_IBS_OBS,
FLAG_SWAB = (1 << 4) * ENABLE_FEATURE_DD_IBS_OBS,
/* end of conv flags */
- FLAG_TWOBUFS = (1 << 5) * ENABLE_FEATURE_DD_IBS_OBS,
- FLAG_COUNT = 1 << 6,
- FLAG_STATUS = 1 << 7,
- FLAG_STATUS_NONE = 1 << 7,
- FLAG_STATUS_NOXFER = 1 << 8,
+ /* start of input flags */
+ FLAG_IFLAG_SHIFT = 5,
+ FLAG_SKIP_BYTES = (1 << 5) * ENABLE_FEATURE_DD_IBS_OBS,
+ /* end of input flags */
+ FLAG_TWOBUFS = (1 << 6) * ENABLE_FEATURE_DD_IBS_OBS,
+ FLAG_COUNT = 1 << 7,
+ FLAG_STATUS = 1 << 8,
+ FLAG_STATUS_NONE = 1 << 9,
+ FLAG_STATUS_NOXFER = 1 << 10,
};
static void dd_output_status(int UNUSED_PARAM cur_signal)
@@ -203,18 +208,47 @@
# define XATOU_SFX xatoul_sfx
#endif
+#if ENABLE_FEATURE_DD_IBS_OBS
+static int parse_comma_flags(char *val, const char *words, const char *error_in)
+{
+ int flags = 0;
+ while (1) {
+ int n;
+ char *arg;
+ /* find ',', replace them with NUL so we can use val for
+ * index_in_strings() without copying.
+ * We rely on val being non-null, else strchr would fault.
+ */
+ arg = strchr(val, ',');
+ if (arg)
+ *arg = '\0';
+ n = index_in_strings(words, val);
+ if (n < 0)
+ bb_error_msg_and_die(bb_msg_invalid_arg_to, val, error_in);
+ flags |= (1 << n);
+ if (!arg) /* no ',' left, so this was the last specifier */
+ break;
+ *arg = ','; /* to preserve ps listing */
+ val = arg + 1; /* skip this keyword and ',' */
+ }
+ return flags;
+}
+#endif
+
int dd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int dd_main(int argc UNUSED_PARAM, char **argv)
{
static const char keywords[] ALIGN1 =
"bs\0""count\0""seek\0""skip\0""if\0""of\0"IF_FEATURE_DD_STATUS("status\0")
#if ENABLE_FEATURE_DD_IBS_OBS
- "ibs\0""obs\0""conv\0"
+ "ibs\0""obs\0""conv\0""iflag\0"
#endif
;
#if ENABLE_FEATURE_DD_IBS_OBS
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";
#endif
#if ENABLE_FEATURE_DD_STATUS
static const char status_words[] ALIGN1 =
@@ -232,6 +266,7 @@
OP_ibs,
OP_obs,
OP_conv,
+ OP_iflag,
/* Must be in the same order as FLAG_XXX! */
OP_conv_notrunc = 0,
OP_conv_sync,
@@ -251,6 +286,7 @@
//ibm from ASCII to alternate EBCDIC
/* Partially implemented: */
//swab swap every pair of input bytes: will abort on non-even reads
+ OP_iflag_skip_bytes,
#endif
};
smallint exitcode = EXIT_FAILURE;
@@ -315,24 +351,11 @@
/*continue;*/
}
if (what == OP_conv) {
- while (1) {
- int n;
- /* find ',', replace them with NUL so we can use val for
- * index_in_strings() without copying.
- * We rely on val being non-null, else strchr would fault.
- */
- arg = strchr(val, ',');
- if (arg)
- *arg = '\0';
- n = index_in_strings(conv_words, val);
- if (n < 0)
- bb_error_msg_and_die(bb_msg_invalid_arg_to, val, "conv");
- G.flags |= (1 << n);
- if (!arg) /* no ',' left, so this was the last specifier */
- break;
- /* *arg = ','; - to preserve ps listing? */
- val = arg + 1; /* skip this keyword and ',' */
- }
+ G.flags |= parse_comma_flags(val, conv_words, "conv");
+ /*continue;*/
+ }
+ if (what == OP_iflag) {
+ G.flags |= parse_comma_flags(val, iflag_words, "iflag") << FLAG_IFLAG_SHIFT;
/*continue;*/
}
#endif
@@ -421,9 +444,10 @@
outfile = bb_msg_standard_output;
}
if (skip) {
- if (lseek(ifd, skip * ibs, SEEK_CUR) < 0) {
+ size_t blocksz = (G.flags & FLAG_SKIP_BYTES) ? 1 : ibs;
+ if (lseek(ifd, skip * blocksz, SEEK_CUR) < 0) {
do {
- ssize_t n = safe_read(ifd, ibuf, ibs);
+ ssize_t n = safe_read(ifd, ibuf, blocksz);
if (n < 0)
goto die_infile;
if (n == 0)