tftp: optional tftp-hpa compat
[oweals/busybox.git] / coreutils / dd.c
index e22938859dcf67e037b9137bcd32f49165c5fb78..b5f3cbec5d4aa4297a97f18d9dc5fd99dabf073c 100644 (file)
@@ -2,15 +2,65 @@
 /*
  * Mini dd implementation for busybox
  *
- *
  * Copyright (C) 2000,2001  Matt Kraai
  *
  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
+//config:config DD
+//config:      bool "dd (7.5 kb)"
+//config:      default y
+//config:      help
+//config:      dd copies a file (from standard input to standard output,
+//config:      by default) using specific input and output blocksizes,
+//config:      while optionally performing conversions on it.
+//config:
+//config:config FEATURE_DD_SIGNAL_HANDLING
+//config:      bool "Enable signal handling for status reporting"
+//config:      default y
+//config:      depends on DD
+//config:      help
+//config:      Sending a SIGUSR1 signal to a running 'dd' process makes it
+//config:      print to standard error the number of records read and written
+//config:      so far, then to resume copying.
+//config:
+//config:      $ dd if=/dev/zero of=/dev/null &
+//config:      $ pid=$!; kill -USR1 $pid; sleep 1; kill $pid
+//config:      10899206+0 records in
+//config:      10899206+0 records out
+//config:
+//config:config FEATURE_DD_THIRD_STATUS_LINE
+//config:      bool "Enable the third status line upon signal"
+//config:      default y
+//config:      depends on DD && FEATURE_DD_SIGNAL_HANDLING
+//config:      help
+//config:      Displays a coreutils-like third status line with transferred bytes,
+//config:      elapsed time and speed.
+//config:
+//config:config FEATURE_DD_IBS_OBS
+//config:      bool "Enable ibs, obs, iflag, oflag and conv options"
+//config:      default y
+//config:      depends on DD
+//config:      help
+//config:      Enable support for writing a certain number of bytes in and out,
+//config:      at a time, and performing conversions on the data stream.
+//config:
+//config:config FEATURE_DD_STATUS
+//config:      bool "Enable status display options"
+//config:      default y
+//config:      depends on DD
+//config:      help
+//config:      Enable support for status=noxfer/none option.
+
+//applet:IF_DD(APPLET_NOEXEC(dd, dd, BB_DIR_BIN, BB_SUID_DROP, dd))
+
+//kbuild:lib-$(CONFIG_DD) += dd.o
 
 //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:       "[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] [oflag=seek_bytes|append]"
+//usage:       )
 //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"
 //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:     "\n       iflag=fullblock Read full blocks"
+//usage:     "\n       oflag=seek_bytes        seek=N is in bytes"
+//usage:     "\n       oflag=append    Open output file in append mode"
+//usage:       )
+//usage:       IF_FEATURE_DD_STATUS(
+//usage:     "\n       status=noxfer   Suppress rate output"
+//usage:     "\n       status=none     Suppress all output"
 //usage:       )
 //usage:     "\n"
-//usage:     "\nN may be suffixed by c (1), w (2), b (512), kD (1000), k (1024), MD, M, GD, G"
+//usage:     "\nN may be suffixed by c (1), w (2), b (512), kB (1000), k (1024), MB, M, GB, G"
 //usage:
 //usage:#define dd_example_usage
 //usage:       "$ dd if=/dev/zero of=/dev/ram1 bs=1M count=4\n"
@@ -41,6 +99,7 @@
 //usage:       "4+0 records out\n"
 
 #include "libbb.h"
+#include "common_bufsiz.h"
 
 /* This is a NOEXEC applet. Be very careful! */
 
@@ -50,33 +109,45 @@ enum {
        ofd = STDOUT_FILENO,
 };
 
-static const struct suffix_mult dd_suffixes[] = {
-       { "c", 1 },
-       { "w", 2 },
-       { "b", 512 },
-       { "kD", 1000 },
-       { "k", 1024 },
-       { "K", 1024 },  /* compat with coreutils dd */
-       { "MD", 1000000 },
-       { "M", 1048576 },
-       { "GD", 1000000000 },
-       { "G", 1073741824 },
-       { "", 0 }
-};
-
 struct globals {
        off_t out_full, out_part, in_full, in_part;
 #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
        unsigned long long total_bytes;
        unsigned long long begin_time_us;
 #endif
+       int flags;
 } FIX_ALIASING;
-#define G (*(struct globals*)&bb_common_bufsiz1)
+#define G (*(struct globals*)bb_common_bufsiz1)
 #define INIT_G() do { \
+       setup_common_bufsiz(); \
        /* we have to zero it out because of NOEXEC */ \
        memset(&G, 0, sizeof(G)); \
 } while (0)
 
+enum {
+       /* Must be in the same order as OP_conv_XXX! */
+       /* (see "flags |= (1 << what)" below) */
+       FLAG_NOTRUNC = (1 << 0) * ENABLE_FEATURE_DD_IBS_OBS,
+       FLAG_SYNC    = (1 << 1) * ENABLE_FEATURE_DD_IBS_OBS,
+       FLAG_NOERROR = (1 << 2) * ENABLE_FEATURE_DD_IBS_OBS,
+       FLAG_FSYNC   = (1 << 3) * ENABLE_FEATURE_DD_IBS_OBS,
+       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,
+       /* end of input flags */
+       /* start of output flags */
+       FLAG_OFLAG_SHIFT = 7,
+       FLAG_SEEK_BYTES = (1 << 7) * ENABLE_FEATURE_DD_IBS_OBS,
+       FLAG_APPEND = (1 << 8) * ENABLE_FEATURE_DD_IBS_OBS,
+       /* end of output flags */
+       FLAG_TWOBUFS = (1 << 9) * ENABLE_FEATURE_DD_IBS_OBS,
+       FLAG_COUNT   = 1 << 10,
+       FLAG_STATUS_NONE = 1 << 11,
+       FLAG_STATUS_NOXFER = 1 << 12,
+};
 
 static void dd_output_status(int UNUSED_PARAM cur_signal)
 {
@@ -93,6 +164,13 @@ static void dd_output_status(int UNUSED_PARAM cur_signal)
                        G.out_full, G.out_part);
 
 #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
+# if ENABLE_FEATURE_DD_STATUS
+       if (G.flags & FLAG_STATUS_NOXFER) /* status=noxfer active? */
+               return;
+       //TODO: should status=none make dd stop reacting to USR1 entirely?
+       //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,
                        /* show fractional digit, use suffixes */
@@ -114,29 +192,33 @@ static void dd_output_status(int UNUSED_PARAM cur_signal)
 #endif
 }
 
-static ssize_t full_write_or_warn(const void *buf, size_t len,
-       const char *const filename)
-{
-       ssize_t n = full_write(ofd, buf, len);
-       if (n < 0)
-               bb_perror_msg("writing '%s'", filename);
-       return n;
-}
-
 static bool write_and_stats(const void *buf, size_t len, size_t obs,
        const char *filename)
 {
-       ssize_t n = full_write_or_warn(buf, len, filename);
-       if (n < 0)
-               return 1;
-       if ((size_t)n == obs)
-               G.out_full++;
-       else if (n) /* > 0 */
-               G.out_part++;
+       ssize_t n;
+
+       n = full_write(ofd, buf, len);
 #if ENABLE_FEATURE_DD_THIRD_STATUS_LINE
-       G.total_bytes += n;
+       if (n > 0)
+               G.total_bytes += n;
 #endif
-       return 0;
+       if ((size_t)n == obs) {
+               G.out_full++;
+               return 0;
+       }
+       if ((size_t)n == len) {
+               G.out_part++;
+               return 0;
+       }
+       /* n is < len (and possibly is -1).
+        * Even if n >= 0, errno is usually set correctly.
+        * For example, if writing to block device and getting ENOSPC,
+        * full_write() first sees a short write, then tries to write
+        * the remainder and gets errno set to ENOSPC.
+        * It returns n > 0 (the amount which it did write).
+        */
+       bb_perror_msg("error writing '%s'", filename);
+       return 1;
 }
 
 #if ENABLE_LFS
@@ -145,30 +227,53 @@ static bool write_and_stats(const void *buf, size_t len, size_t obs,
 # 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)
 {
-       enum {
-               /* Must be in the same order as OP_conv_XXX! */
-               /* (see "flags |= (1 << what)" below) */
-               FLAG_NOTRUNC = (1 << 0) * ENABLE_FEATURE_DD_IBS_OBS,
-               FLAG_SYNC    = (1 << 1) * ENABLE_FEATURE_DD_IBS_OBS,
-               FLAG_NOERROR = (1 << 2) * ENABLE_FEATURE_DD_IBS_OBS,
-               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,
-       };
        static const char keywords[] ALIGN1 =
-               "bs\0""count\0""seek\0""skip\0""if\0""of\0"
+               "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""oflag\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""fullblock\0";
+       static const char oflag_words[] ALIGN1 =
+               "seek_bytes\0append\0";
+#endif
+#if ENABLE_FEATURE_DD_STATUS
+       static const char status_words[] ALIGN1 =
+               "none\0""noxfer\0";
 #endif
        enum {
                OP_bs = 0,
@@ -177,10 +282,13 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
                OP_skip,
                OP_if,
                OP_of,
+               IF_FEATURE_DD_STATUS(OP_status,)
 #if ENABLE_FEATURE_DD_IBS_OBS
                OP_ibs,
                OP_obs,
                OP_conv,
+               OP_iflag,
+               OP_oflag,
                /* Must be in the same order as FLAG_XXX! */
                OP_conv_notrunc = 0,
                OP_conv_sync,
@@ -200,23 +308,31 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
        //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,
+               OP_iflag_fullblock,
+               OP_oflag_seek_bytes,
 #endif
        };
        smallint exitcode = EXIT_FAILURE;
-       size_t ibs = 512, obs = 512;
        int i;
-       char *ibuf, *obuf;
-       /* And these are all zeroed at once! */
+       size_t ibs = 512;
+       char *ibuf;
+#if ENABLE_FEATURE_DD_IBS_OBS
+       size_t obs = 512;
+       char *obuf;
+#else
+# define obs  ibs
+# define obuf ibuf
+#endif
+       /* These are all zeroed at once! */
        struct {
-               int flags;
-               size_t oc;
+               IF_FEATURE_DD_IBS_OBS(size_t ocount;)
                ssize_t prev_read_size; /* for detecting swab failure */
                off_t count;
                off_t seek, skip;
                const char *infile, *outfile;
        } Z;
-#define flags   (Z.flags  )
-#define oc      (Z.oc     )
+#define ocount  (Z.ocount )
 #define prev_read_size (Z.prev_read_size)
 #define count   (Z.count  )
 #define seek    (Z.seek   )
@@ -251,50 +367,43 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
 #if ENABLE_FEATURE_DD_IBS_OBS
                if (what == OP_ibs) {
                        /* Must fit into positive ssize_t */
-                       ibs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, dd_suffixes);
+                       ibs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, cwbkMG_suffixes);
                        /*continue;*/
                }
                if (what == OP_obs) {
-                       obs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, dd_suffixes);
+                       obs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, cwbkMG_suffixes);
                        /*continue;*/
                }
                if (what == OP_conv) {
-                       while (1) {
-                               /* 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';
-                               what = index_in_strings(conv_words, val);
-                               if (what < 0)
-                                       bb_error_msg_and_die(bb_msg_invalid_arg, val, "conv");
-                               flags |= (1 << what);
-                               if (!arg) /* no ',' left, so this was the last specifier */
-                                       break;
-                               /* *arg = ','; - to preserve ps listing? */
-                               val = arg + 1; /* skip this keyword and ',' */
-                       }
-                       continue; /* we trashed 'what', can't fall through */
+                       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;*/
+               }
+               if (what == OP_oflag) {
+                       G.flags |= parse_comma_flags(val, oflag_words, "oflag") << FLAG_OFLAG_SHIFT;
+                       /*continue;*/
                }
 #endif
                if (what == OP_bs) {
-                       ibs = obs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, dd_suffixes);
+                       ibs = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, cwbkMG_suffixes);
+                       obs = ibs;
                        /*continue;*/
                }
                /* These can be large: */
                if (what == OP_count) {
-                       flags |= FLAG_COUNT;
-                       count = XATOU_SFX(val, dd_suffixes);
+                       G.flags |= FLAG_COUNT;
+                       count = XATOU_SFX(val, cwbkMG_suffixes);
                        /*continue;*/
                }
                if (what == OP_seek) {
-                       seek = XATOU_SFX(val, dd_suffixes);
+                       seek = XATOU_SFX(val, cwbkMG_suffixes);
                        /*continue;*/
                }
                if (what == OP_skip) {
-                       skip = XATOU_SFX(val, dd_suffixes);
+                       skip = XATOU_SFX(val, cwbkMG_suffixes);
                        /*continue;*/
                }
                if (what == OP_if) {
@@ -305,14 +414,27 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
                        outfile = val;
                        /*continue;*/
                }
+#if ENABLE_FEATURE_DD_STATUS
+               if (what == OP_status) {
+                       int n;
+                       n = index_in_strings(status_words, val);
+                       if (n < 0)
+                               bb_error_msg_and_die(bb_msg_invalid_arg_to, val, "status");
+                       G.flags |= FLAG_STATUS_NONE << n;
+                       /*continue;*/
+               }
+#endif
        } /* end of "for (argv[i])" */
 
 //XXX:FIXME for huge ibs or obs, malloc'ing them isn't the brightest idea ever
-       ibuf = obuf = xmalloc(ibs);
+       ibuf = xmalloc(ibs);
+       obuf = ibuf;
+#if ENABLE_FEATURE_DD_IBS_OBS
        if (ibs != obs) {
-               flags |= FLAG_TWOBUFS;
+               G.flags |= FLAG_TWOBUFS;
                obuf = xmalloc(obs);
        }
+#endif
 
 #if ENABLE_FEATURE_DD_SIGNAL_HANDLING
        signal_SA_RESTART_empty_mask(SIGUSR1, dd_output_status);
@@ -321,21 +443,24 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
        G.begin_time_us = monotonic_us();
 #endif
 
-       if (infile != NULL)
+       if (infile) {
                xmove_fd(xopen(infile, O_RDONLY), ifd);
-       else {
+       else {
                infile = bb_msg_standard_input;
        }
-       if (outfile != NULL) {
+       if (outfile) {
                int oflag = O_WRONLY | O_CREAT;
 
-               if (!seek && !(flags & FLAG_NOTRUNC))
+               if (!seek && !(G.flags & FLAG_NOTRUNC))
                        oflag |= O_TRUNC;
+               if (G.flags & FLAG_APPEND)
+                       oflag |= O_APPEND;
 
                xmove_fd(xopen(outfile, oflag), ofd);
 
-               if (seek && !(flags & FLAG_NOTRUNC)) {
-                       if (ftruncate(ofd, seek * obs) < 0) {
+               if (seek && !(G.flags & FLAG_NOTRUNC)) {
+                       size_t blocksz = (G.flags & FLAG_SEEK_BYTES) ? 1 : obs;
+                       if (ftruncate(ofd, seek * blocksz) < 0) {
                                struct stat st;
 
                                if (fstat(ofd, &st) < 0
@@ -350,30 +475,42 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
                outfile = bb_msg_standard_output;
        }
        if (skip) {
-               if (lseek(ifd, skip * ibs, SEEK_CUR) < 0) {
-                       while (skip-- > 0) {
-                               ssize_t n = safe_read(ifd, ibuf, ibs);
+               size_t blocksz = (G.flags & FLAG_SKIP_BYTES) ? 1 : ibs;
+               if (lseek(ifd, skip * blocksz, SEEK_CUR) < 0) {
+                       do {
+                               ssize_t n;
+#if ENABLE_FEATURE_DD_IBS_OBS
+                               if (G.flags & FLAG_FULLBLOCK)
+                                       n = full_read(ifd, ibuf, blocksz);
+                               else
+#endif
+                                       n = safe_read(ifd, ibuf, blocksz);
                                if (n < 0)
                                        goto die_infile;
                                if (n == 0)
                                        break;
-                       }
+                       } while (--skip != 0);
                }
        }
        if (seek) {
-               if (lseek(ofd, seek * obs, SEEK_CUR) < 0)
+               size_t blocksz = (G.flags & FLAG_SEEK_BYTES) ? 1 : obs;
+               if (lseek(ofd, seek * blocksz, SEEK_CUR) < 0)
                        goto die_outfile;
        }
 
-       while (!(flags & FLAG_COUNT) || (G.in_full + G.in_part != count)) {
+       while (!(G.flags & FLAG_COUNT) || (G.in_full + G.in_part != count)) {
                ssize_t n;
-
-               n = safe_read(ifd, ibuf, ibs);
+#if ENABLE_FEATURE_DD_IBS_OBS
+               if (G.flags & FLAG_FULLBLOCK)
+                       n = full_read(ifd, ibuf, ibs);
+               else
+#endif
+                       n = safe_read(ifd, ibuf, ibs);
                if (n == 0)
                        break;
                if (n < 0) {
                        /* "Bad block" */
-                       if (!(flags & FLAG_NOERROR))
+                       if (!(G.flags & FLAG_NOERROR))
                                goto die_infile;
                        bb_simple_perror_msg(infile);
                        /* GNU dd with conv=noerror skips over bad blocks */
@@ -382,8 +519,9 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
                         * conv=noerror just ignores input bad blocks */
                        n = 0;
                }
-               if (flags & FLAG_SWAB) {
-                       uint16_t *p16, *end;
+               if (G.flags & FLAG_SWAB) {
+                       uint16_t *p16;
+                       ssize_t n2;
 
                        /* Our code allows only last read to be odd-sized */
                        if (prev_read_size & 1)
@@ -391,16 +529,13 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
                                                (unsigned long)prev_read_size);
                        prev_read_size = n;
 
-                       /*
-                        * If n is odd, last byte is not swapped:
+                       /* If n is odd, last byte is not swapped:
                         *  echo -n "qwe" | dd conv=swab
                         * prints "wqe".
-                        * The code does not handle correctly odd-sized reads
-                        * in the *middle* of the input. FIXME.
                         */
                        p16 = (void*) ibuf;
-                       end = (void*) (ibuf + (n & ~(ssize_t)1));
-                       while (p16 < end) {
+                       n2 = (n >> 1);
+                       while (--n2 >= 0) {
                                *p16 = bswap_16(*p16);
                                p16++;
                        }
@@ -409,42 +544,47 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
                        G.in_full++;
                else {
                        G.in_part++;
-                       if (flags & FLAG_SYNC) {
+                       if (G.flags & FLAG_SYNC) {
                                memset(ibuf + n, 0, ibs - n);
                                n = ibs;
                        }
                }
-               if (flags & FLAG_TWOBUFS) {
+#if ENABLE_FEATURE_DD_IBS_OBS
+               if (G.flags & FLAG_TWOBUFS) {
                        char *tmp = ibuf;
                        while (n) {
-                               size_t d = obs - oc;
-
+                               size_t d = obs - ocount;
                                if (d > (size_t)n)
                                        d = n;
-                               memcpy(obuf + oc, tmp, d);
+                               memcpy(obuf + ocount, tmp, d);
                                n -= d;
                                tmp += d;
-                               oc += d;
-                               if (oc == obs) {
+                               ocount += d;
+                               if (ocount == obs) {
                                        if (write_and_stats(obuf, obs, obs, outfile))
                                                goto out_status;
-                                       oc = 0;
+                                       ocount = 0;
                                }
                        }
-               } else if (write_and_stats(ibuf, n, obs, outfile))
-                       goto out_status;
-
-               if (flags & FLAG_FSYNC) {
-                       if (fsync(ofd) < 0)
-                               goto die_outfile;
+               } else
+#endif
+               {
+                       if (write_and_stats(ibuf, n, obs, outfile))
+                               goto out_status;
                }
        }
 
-       if (ENABLE_FEATURE_DD_IBS_OBS && oc) {
-               ssize_t w = full_write_or_warn(obuf, oc, outfile);
-               if (w < 0) goto out_status;
-               if (w > 0) G.out_part++;
+       if (G.flags & FLAG_FSYNC) {
+               if (fsync(ofd) < 0)
+                       goto die_outfile;
        }
+
+#if ENABLE_FEATURE_DD_IBS_OBS
+       if (ocount != 0) {
+               if (write_and_stats(obuf, ocount, obs, outfile))
+                       goto out_status;
+       }
+#endif
        if (close(ifd) < 0) {
  die_infile:
                bb_simple_perror_msg_and_die(infile);
@@ -457,11 +597,12 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
 
        exitcode = EXIT_SUCCESS;
  out_status:
-       dd_output_status(0);
+       if (!ENABLE_FEATURE_DD_STATUS || !(G.flags & FLAG_STATUS_NONE))
+               dd_output_status(0);
 
        if (ENABLE_FEATURE_CLEAN_UP) {
                free(obuf);
-               if (flags & FLAG_TWOBUFS)
+               if (G.flags & FLAG_TWOBUFS)
                        free(ibuf);
        }