tftp: optional tftp-hpa compat
[oweals/busybox.git] / coreutils / dd.c
index 0150aff965c8d6bb95a24b8b8f5da862a2e4dc8d..b5f3cbec5d4aa4297a97f18d9dc5fd99dabf073c 100644 (file)
@@ -7,57 +7,60 @@
  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
 //config:config DD
-//config:      bool "dd (7.1 kb)"
+//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:      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:      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:      $ 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:      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 and conv options"
+//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:      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.
+//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] [iflag=skip_bytes]")
+//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"
@@ -79,6 +82,9 @@
 //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"
@@ -130,11 +136,17 @@ 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,
        /* end of input flags */
-       FLAG_TWOBUFS = (1 << 6) * ENABLE_FEATURE_DD_IBS_OBS,
-       FLAG_COUNT   = 1 << 7,
-       FLAG_STATUS_NONE = 1 << 8,
-       FLAG_STATUS_NOXFER = 1 << 9,
+       /* 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)
@@ -180,29 +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
@@ -244,14 +260,16 @@ 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""iflag\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";
+               "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 =
@@ -270,6 +288,7 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
                OP_obs,
                OP_conv,
                OP_iflag,
+               OP_oflag,
                /* Must be in the same order as FLAG_XXX! */
                OP_conv_notrunc = 0,
                OP_conv_sync,
@@ -290,6 +309,8 @@ 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_fullblock,
+               OP_oflag_seek_bytes,
 #endif
        };
        smallint exitcode = EXIT_FAILURE;
@@ -305,13 +326,13 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
 #endif
        /* These are all zeroed at once! */
        struct {
-               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 oc      (Z.oc     )
+#define ocount  (Z.ocount )
 #define prev_read_size (Z.prev_read_size)
 #define count   (Z.count  )
 #define seek    (Z.seek   )
@@ -361,6 +382,10 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
                        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 = xatoul_range_sfx(val, 1, ((size_t)-1L)/2, cwbkMG_suffixes);
@@ -428,11 +453,14 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
 
                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 && !(G.flags & FLAG_NOTRUNC)) {
-                       if (ftruncate(ofd, seek * obs) < 0) {
+                       size_t blocksz = (G.flags & FLAG_SEEK_BYTES) ? 1 : obs;
+                       if (ftruncate(ofd, seek * blocksz) < 0) {
                                struct stat st;
 
                                if (fstat(ofd, &st) < 0
@@ -450,7 +478,13 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
                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, blocksz);
+                               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)
@@ -459,14 +493,19 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
                }
        }
        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 (!(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) {
@@ -510,24 +549,26 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
                                n = ibs;
                        }
                }
+#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 {
+               } else
+#endif
+               {
                        if (write_and_stats(ibuf, n, obs, outfile))
                                goto out_status;
                }
@@ -538,10 +579,12 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
                        goto die_outfile;
        }
 
-       if (ENABLE_FEATURE_DD_IBS_OBS && oc) {
-               if (write_and_stats(obuf, oc, obs, 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);