dd: support for O_DIRECT i/o
Based on patch by Akash Hadke <hadkeakash4@gmail.com> function old new delta dd_read - 66 +66 clear_O_DIRECT - 55 +55 write_and_stats 102 135 +33 dd_main 1578 1601 +23 static.oflag_words 19 26 +7 static.iflag_words 22 29 +7 packed_usage 33665 33668 +3 ------------------------------------------------------------------------------ (add/remove: 2/0 grow/shrink: 5/0 up/down: 194/0) Total: 194 bytes Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
parent
c7b858ff8d
commit
2aaacc1453
111
coreutils/dd.c
111
coreutils/dd.c
@ -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] [oflag=seek_bytes|append]"
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//usage: " [iflag=skip_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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@ -82,9 +82,11 @@
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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=fullblock Read full blocks"
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//usage: "\n oflag=seek_bytes seek=N is in bytes"
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//usage: "\n oflag=append Open output file in append mode"
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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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//usage: "\n iflag=fullblock Read full blocks"
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//usage: "\n oflag=append Open output in append mode"
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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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@ -137,16 +139,18 @@ enum {
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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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/* end of input flags */
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/* start of output flags */
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FLAG_OFLAG_SHIFT = 7,
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FLAG_SEEK_BYTES = (1 << 7) * ENABLE_FEATURE_DD_IBS_OBS,
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FLAG_APPEND = (1 << 8) * ENABLE_FEATURE_DD_IBS_OBS,
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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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/* end of output flags */
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FLAG_TWOBUFS = (1 << 9) * ENABLE_FEATURE_DD_IBS_OBS,
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FLAG_COUNT = 1 << 10,
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FLAG_STATUS_NONE = 1 << 11,
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FLAG_STATUS_NOXFER = 1 << 12,
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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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};
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static void dd_output_status(int UNUSED_PARAM cur_signal)
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@ -192,12 +196,50 @@ static void dd_output_status(int UNUSED_PARAM cur_signal)
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#endif
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}
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#if ENABLE_FEATURE_DD_IBS_OBS
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static int clear_O_DIRECT(int fd)
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{
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if (errno == EINVAL) {
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int fl = fcntl(fd, F_GETFL);
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if (fl & O_DIRECT) {
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fcntl(fd, F_SETFL, fl & ~O_DIRECT);
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return 1;
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}
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}
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return 0;
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}
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#endif
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static ssize_t dd_read(void *ibuf, size_t ibs)
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{
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ssize_t n;
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#if ENABLE_FEATURE_DD_IBS_OBS
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read_again:
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if (G.flags & FLAG_FULLBLOCK)
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n = full_read(ifd, ibuf, ibs);
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else
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#endif
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n = safe_read(ifd, ibuf, ibs);
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#if ENABLE_FEATURE_DD_IBS_OBS
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if (n < 0 && (G.flags & FLAG_IDIRECT) && clear_O_DIRECT(ifd))
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goto read_again;
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#endif
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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;
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IF_FEATURE_DD_IBS_OBS(write_again:)
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n = full_write(ofd, buf, len);
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#if ENABLE_FEATURE_DD_IBS_OBS
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if (n < 0 && (G.flags & FLAG_ODIRECT) && clear_O_DIRECT(ofd))
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goto write_again;
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#endif
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#if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
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if (n > 0)
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G.total_bytes += n;
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@ -254,6 +296,14 @@ static int parse_comma_flags(char *val, const char *words, const char *error_in)
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}
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#endif
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static void *alloc_buf(size_t size)
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{
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/* Important for "{i,o}flag=direct" - buffers must be page aligned */
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if (size >= bb_getpagesize())
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return xmmap_anon(size);
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return xmalloc(size);
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}
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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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@ -267,9 +317,9 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
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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";
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"skip_bytes\0""fullblock\0""direct\0";
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static const char oflag_words[] ALIGN1 =
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"seek_bytes\0append\0";
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"seek_bytes\0append\0""direct\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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@ -310,7 +360,9 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
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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_fullblock,
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OP_iflag_direct,
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OP_oflag_seek_bytes,
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OP_oflag_direct,
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#endif
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};
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smallint exitcode = EXIT_FAILURE;
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@ -426,13 +478,12 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
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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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ibuf = alloc_buf(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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obuf = alloc_buf(obs);
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}
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#endif
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@ -444,7 +495,12 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
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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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int iflag = O_RDONLY;
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#if ENABLE_FEATURE_DD_IBS_OBS
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if (G.flags & FLAG_IDIRECT)
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iflag |= O_DIRECT;
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#endif
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xmove_fd(xopen(infile, iflag), ifd);
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} else {
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infile = bb_msg_standard_input;
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}
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@ -455,7 +511,10 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
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oflag |= O_TRUNC;
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if (G.flags & FLAG_APPEND)
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oflag |= O_APPEND;
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#if ENABLE_FEATURE_DD_IBS_OBS
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if (G.flags & FLAG_ODIRECT)
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oflag |= O_DIRECT;
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#endif
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xmove_fd(xopen(outfile, oflag), ofd);
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if (seek && !(G.flags & FLAG_NOTRUNC)) {
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@ -478,13 +537,7 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
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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;
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#if ENABLE_FEATURE_DD_IBS_OBS
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if (G.flags & FLAG_FULLBLOCK)
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n = full_read(ifd, ibuf, blocksz);
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else
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#endif
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n = safe_read(ifd, ibuf, blocksz);
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ssize_t n = dd_read(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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@ -499,13 +552,7 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
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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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#if ENABLE_FEATURE_DD_IBS_OBS
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if (G.flags & FLAG_FULLBLOCK)
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n = full_read(ifd, ibuf, ibs);
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else
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#endif
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n = safe_read(ifd, ibuf, ibs);
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ssize_t n = dd_read(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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@ -600,11 +647,13 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
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if (!ENABLE_FEATURE_DD_STATUS || !(G.flags & FLAG_STATUS_NONE))
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dd_output_status(0);
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#if 0 /* can't just free(), they can be mmap()ed */
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if (ENABLE_FEATURE_CLEAN_UP) {
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free(obuf);
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if (G.flags & FLAG_TWOBUFS)
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free(ibuf);
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}
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#endif
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return exitcode;
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}
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