@@ -46,9 +46,9 @@ STEXI
ETEXI
DEF("dd", img_dd,
- "dd [--image-opts] [-f fmt] [-O output_fmt] [bs=block_size] [count=blocks] [skip=blocks] if=input of=output")
+ "dd [--image-opts] [-f fmt] [-O output_fmt] [bs=block_size] [count=blocks] [skip=blocks] [conv=notrunc] if=input of=output")
STEXI
-@item dd [--image-opts] [-f @var{fmt}] [-O @var{output_fmt}] [bs=@var{block_size}] [count=@var{blocks}] [skip=@var{blocks}] if=@var{input} of=@var{output}
+@item dd [--image-opts] [-f @var{fmt}] [-O @var{output_fmt}] [bs=@var{block_size}] [count=@var{blocks}] [skip=@var{blocks}] [conv=notrunc] if=@var{input} of=@var{output}
ETEXI
DEF("info", img_info,
@@ -174,7 +174,8 @@ static void QEMU_NORETURN help(void)
" 'count=N' copy only N input blocks\n"
" 'if=FILE' read from FILE\n"
" 'of=FILE' write to FILE\n"
- " 'skip=N' skip N bs-sized blocks at the start of input\n";
+ " 'skip=N' skip N bs-sized blocks at the start of input\n"
+ " 'conv=notrunc' do not truncate the output file\n";
printf("%s\nSupported formats:", help_msg);
bdrv_iterate_format(format_print, NULL);
@@ -3807,10 +3808,12 @@ out:
#define C_IF 04
#define C_OF 010
#define C_SKIP 020
+#define C_CONV 040
struct DdInfo {
unsigned int flags;
int64_t count;
+ unsigned int conv;
};
struct DdIo {
@@ -3894,6 +3897,21 @@ static int img_dd_skip(const char *arg,
return 0;
}
+#define C_NOTRUNC 01
+
+static int img_dd_conv(const char *arg,
+ struct DdIo *in, struct DdIo *out,
+ struct DdInfo *dd)
+{
+ if (!strcmp(arg, "notrunc")) {
+ dd->conv |= C_NOTRUNC;
+ return 0;
+ } else {
+ error_report("invalid conversion: '%s'", arg);
+ return 1;
+ }
+}
+
static int img_dd(int argc, char **argv)
{
int ret = 0;
@@ -3913,6 +3931,7 @@ static int img_dd(int argc, char **argv)
struct DdInfo dd = {
.flags = 0,
.count = 0,
+ .conv = 0
};
struct DdIo in = {
.bsz = 512, /* Block size is by default 512 bytes */
@@ -3933,6 +3952,7 @@ static int img_dd(int argc, char **argv)
{ "if", img_dd_if, C_IF },
{ "of", img_dd_of, C_OF },
{ "skip", img_dd_skip, C_SKIP },
+ { "conv", img_dd_conv, C_CONV },
{ NULL, NULL, 0 }
};
const struct option long_options[] = {
@@ -3997,6 +4017,14 @@ static int img_dd(int argc, char **argv)
g_free(arg);
arg = NULL;
}
+ if (!(dd.conv & C_NOTRUNC)) {
+ /* We make conv=notrunc mandatory for the moment to avoid accidental
+ destruction of the output image. Needs to be changed when a better
+ solution is found */
+ error_report("conv=notrunc not specified");
+ ret = -1;
+ goto out;
+ }
if (!(dd.flags & C_IF && dd.flags & C_OF)) {
error_report("Must specify both input and output files");
@@ -150,9 +150,12 @@ sets the number of input blocks to copy
@item if=@var{input}
sets the input file
@item of=@var{output}
-sets the output file
+sets the output file. dd truncates the output file to zero if 'conv=notrunc'
+is not specified.
@item skip=@var{blocks}
sets the number of input blocks to skip
+@item conv=notrunc
+makes dd not truncate output file to zero
@end table
Command description:
@@ -326,7 +329,7 @@ skipped. This is useful for formats such as @code{rbd} if the target
volume has already been created with site specific options that cannot
be supplied through qemu-img.
-@item dd [-f @var{fmt}] [-O @var{output_fmt}] [bs=@var{block_size}] [count=@var{blocks}] [skip=@var{blocks}] if=@var{input} of=@var{output}
+@item dd [-f @var{fmt}] [-O @var{output_fmt}] [bs=@var{block_size}] [count=@var{blocks}] [skip=@var{blocks}] [conv=notrunc] if=@var{input} of=@var{output}
Dd copies from @var{input} file to @var{output} file converting it from
@var{fmt} format to @var{output_fmt} format.
@@ -53,7 +53,7 @@ $QEMU_IO -c "write -P 0xa 0 $size" "$TEST_IMG" | _filter_qemu_io
echo
echo "== Converting the image with dd =="
-$QEMU_IMG dd if="$TEST_IMG" of="$TEST_IMG.out" -O "$IMGFMT"
+$QEMU_IMG dd if="$TEST_IMG" of="$TEST_IMG.out" conv=notrunc -O "$IMGFMT"
TEST_IMG="$TEST_IMG.out" _check_test_img
echo
@@ -55,7 +55,8 @@ for bs in $TEST_SIZES; do
echo
echo "== Converting the image with dd with a block size of $bs =="
- $QEMU_IMG dd if="$TEST_IMG" of="$TEST_IMG.out" bs=$bs -O "$IMGFMT"
+ $QEMU_IMG dd if="$TEST_IMG" of="$TEST_IMG.out" bs=$bs conv=notrunc \
+ -O "$IMGFMT"
TEST_IMG="$TEST_IMG.out" _check_test_img
echo
@@ -55,10 +55,11 @@ for skip in $TEST_SKIP_BLOCKS; do
echo
echo "== Converting the image with dd with skip=$skip =="
- $QEMU_IMG dd if="$TEST_IMG" of="$TEST_IMG.out" skip="$skip" -O "$IMGFMT" \
- 2> /dev/null
+ $QEMU_IMG dd if="$TEST_IMG" of="$TEST_IMG.out" skip="$skip" conv=notrunc \
+ -O "$IMGFMT" 2> /dev/null
TEST_IMG="$TEST_IMG.out" _check_test_img
- dd if="$TEST_IMG" of="$TEST_IMG.out.dd" skip="$skip" status=none
+ dd if="$TEST_IMG" of="$TEST_IMG.out.dd" skip="$skip" conv=notrunc \
+ status=none
echo
echo "== Compare the images with qemu-img compare =="
This adds the conv=notrunc option to dd which tells dd to not truncate the output. For the time being we make it mandatory to specify conv=notrunc. Signed-off-by: Reda Sallahi <fullmanet@gmail.com> --- Depends on: [PATCH v5] qemu-img: add skip option to dd Changes from v1: * Added comment qemu-img-cmds.hx | 4 ++-- qemu-img.c | 30 +++++++++++++++++++++++++++++- qemu-img.texi | 7 +++++-- tests/qemu-iotests/158 | 2 +- tests/qemu-iotests/159 | 3 ++- tests/qemu-iotests/160 | 7 ++++--- 6 files changed, 43 insertions(+), 10 deletions(-)