dd was creating an output image regardless of whether there was one already created. With this patch we try to open first the output image and resize it if necessary.
Signed-off-by: Reda Sallahi <fullma...@gmail.com> --- Depends on: [PATCH v2] qemu-img: add conv=notrunc option to dd qemu-img.c | 91 +++++++++++++++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 76 insertions(+), 15 deletions(-) diff --git a/qemu-img.c b/qemu-img.c index 7c546c1..dfa0e63 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -3919,6 +3919,8 @@ static int img_dd(int argc, char **argv) char *tmp; BlockDriver *drv = NULL, *proto_drv = NULL; BlockBackend *blk1 = NULL, *blk2 = NULL; + BlockDriverState *bs = NULL; + QDict *qoptions = NULL; QemuOpts *opts = NULL; QemuOptsList *create_opts = NULL; Error *local_err = NULL; @@ -4080,22 +4082,60 @@ static int img_dd(int argc, char **argv) size = dd.count * in.bsz; } - /* Overflow means the specified offset is beyond input image's size */ - if (dd.flags & C_SKIP && (in.offset > INT64_MAX / in.bsz || - size < in.bsz * in.offset)) { - qemu_opt_set_number(opts, BLOCK_OPT_SIZE, 0, &error_abort); - } else { - qemu_opt_set_number(opts, BLOCK_OPT_SIZE, - size - in.bsz * in.offset, &error_abort); - } + qoptions = qdict_new(); + qdict_put(qoptions, "driver", qstring_from_str(out_fmt)); - ret = bdrv_create(drv, out.filename, opts, &local_err); - if (ret < 0) { - error_reportf_err(local_err, - "%s: error while creating output image: ", - out.filename); - ret = -1; - goto out; + bs = bdrv_open(out.filename, NULL, qoptions, BDRV_O_RDWR, &local_err); + + if (!bs) { + drv = bdrv_find_format(out_fmt); + if (!drv) { + error_report("Unknown file format"); + ret = -1; + goto out; + } + proto_drv = bdrv_find_protocol(out.filename, true, &local_err); + + if (!proto_drv) { + error_report_err(local_err); + ret = -1; + goto out; + } + if (!drv->create_opts) { + error_report("Format driver '%s' does not support image creation", + drv->format_name); + ret = -1; + goto out; + } + if (!proto_drv->create_opts) { + error_report("Protocol driver '%s' does not support image creation", + proto_drv->format_name); + ret = -1; + goto out; + } + create_opts = qemu_opts_append(create_opts, drv->create_opts); + create_opts = qemu_opts_append(create_opts, proto_drv->create_opts); + + opts = qemu_opts_create(create_opts, NULL, 0, &error_abort); + + /* Overflow means the specified offset is beyond input image's size */ + if (dd.flags & C_SKIP && (in.offset > INT64_MAX / in.bsz || + size < in.offset * in.bsz)) { + qemu_opt_set_number(opts, BLOCK_OPT_SIZE, + 0, &error_abort); + } else { + qemu_opt_set_number(opts, BLOCK_OPT_SIZE, + size - in.offset * in.bsz, &error_abort); + } + + ret = bdrv_create(drv, out.filename, opts, &local_err); + if (ret < 0) { + error_reportf_err(local_err, + "%s: error while creating output image: ", + out.filename); + ret = -1; + goto out; + } } blk2 = img_open(image_opts, out.filename, out_fmt, BDRV_O_RDWR, @@ -4117,6 +4157,26 @@ static int img_dd(int argc, char **argv) in_pos = in.offset * in.bsz; } + if (bs) { + int64_t blk2sz = blk_getlength(blk2); + if (blk2sz < 0) { + error_report("Failed to get size for '%s'", in.filename); + ret = -1; + goto out; + } + + if (!(dd.conv & C_NOTRUNC)) { + blk_truncate(blk2, 0); + } + if (!(dd.flags & C_SKIP) || (in.offset <= INT64_MAX / in.bsz && + size >= in.offset * in.bsz)) { + if (!(dd.conv & C_NOTRUNC) || + blk2sz < size - in.offset * in.bsz) { + blk_truncate(blk2, size - in.offset * in.bsz); + } + } + } + in.buf = g_new(uint8_t, in.bsz); for (out_pos = 0; in_pos < size; block_count++) { @@ -4152,6 +4212,7 @@ out: qemu_opts_free(create_opts); blk_unref(blk1); blk_unref(blk2); + bdrv_unref(bs); g_free(in.filename); g_free(out.filename); g_free(in.buf); -- 2.9.2