dd now truncates files at the end its write, this can be turned of by

specifying conv=notrunc in the command line

This conforms to GNU dd behaviour

diff --git a/coreutils/dd.c b/coreutils/dd.c
index 84f3211..5ab0a90 100644 (file)
--- a/coreutils/dd.c
+++ b/coreutils/dd.c
@@ -48,6 +48,7 @@ extern int dd_main(int argc, char **argv)
        int outFd;
        int inCc = 0;
        int outCc;
+       int trunc=TRUE;
        long blockSize = 512;
        uintmax_t skipBlocks = 0;
        uintmax_t seekBlocks = 0;
@@ -57,6 +58,7 @@ extern int dd_main(int argc, char **argv)
        uintmax_t totalSize;
        uintmax_t readSize;
        unsigned char buf[BUFSIZ];
+       char *keyword = NULL;
 
        argc--;
        argv++;
@@ -69,7 +71,7 @@ extern int dd_main(int argc, char **argv)
                        outFile = ((strchr(*argv, '=')) + 1);
                else if (strncmp("count", *argv, 5) == 0) {
                        count = getNum((strchr(*argv, '=')) + 1);
-                       if (count <= 0) {
+                       if (count < 0) {
                                errorMsg("Bad count value %s\n", *argv);
                                goto usage;
                        }
@@ -92,7 +94,10 @@ extern int dd_main(int argc, char **argv)
                                errorMsg("Bad seek value %s\n", *argv);
                                goto usage;
                        }
-
+               } else if (strncmp(*argv, "conv", 4) == 0) {
+                       keyword = (strchr(*argv, '=') + 1);
+                       if (strcmp(keyword, "notrunc") == 0) 
+                               trunc=FALSE;
                } else {
                        goto usage;
                }
@@ -141,7 +146,9 @@ extern int dd_main(int argc, char **argv)
                        break;
                outTotal += outCc;
         }
-
+       if (trunc == TRUE) {
+               ftruncate(outFd, lseek(outFd, 0, SEEK_CUR));
+       }
        /* Note that we are not freeing memory or closing
         * files here, to save a few bytes. */
 #ifdef BB_FEATURE_CLEAN_UP

diff --git a/dd.c b/dd.c
index 84f3211..5ab0a90 100644 (file)
--- a/dd.c
+++ b/dd.c
@@ -48,6 +48,7 @@ extern int dd_main(int argc, char **argv)
        int outFd;
        int inCc = 0;
        int outCc;
+       int trunc=TRUE;
        long blockSize = 512;
        uintmax_t skipBlocks = 0;
        uintmax_t seekBlocks = 0;
@@ -57,6 +58,7 @@ extern int dd_main(int argc, char **argv)
        uintmax_t totalSize;
        uintmax_t readSize;
        unsigned char buf[BUFSIZ];
+       char *keyword = NULL;
 
        argc--;
        argv++;
@@ -69,7 +71,7 @@ extern int dd_main(int argc, char **argv)
                        outFile = ((strchr(*argv, '=')) + 1);
                else if (strncmp("count", *argv, 5) == 0) {
                        count = getNum((strchr(*argv, '=')) + 1);
-                       if (count <= 0) {
+                       if (count < 0) {
                                errorMsg("Bad count value %s\n", *argv);
                                goto usage;
                        }
@@ -92,7 +94,10 @@ extern int dd_main(int argc, char **argv)
                                errorMsg("Bad seek value %s\n", *argv);
                                goto usage;
                        }
-
+               } else if (strncmp(*argv, "conv", 4) == 0) {
+                       keyword = (strchr(*argv, '=') + 1);
+                       if (strcmp(keyword, "notrunc") == 0) 
+                               trunc=FALSE;
                } else {
                        goto usage;
                }
@@ -141,7 +146,9 @@ extern int dd_main(int argc, char **argv)
                        break;
                outTotal += outCc;
         }
-
+       if (trunc == TRUE) {
+               ftruncate(outFd, lseek(outFd, 0, SEEK_CUR));
+       }
        /* Note that we are not freeing memory or closing
         * files here, to save a few bytes. */
 #ifdef BB_FEATURE_CLEAN_UP