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

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specifying conv=notrunc in the command line

This conforms to GNU dd behaviour
This commit is contained in:
Glenn L McGrath 2000-09-11 00:32:13 +00:00
parent de34e43755
commit f0b073f55a
2 changed files with 20 additions and 6 deletions
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13
coreutils/dd.c
View File

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

13
dd.c
View File

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