Am 26.01.2016 um 14:34 hat Daniel P. Berrange geschrieben:
> Allow creation of user creatable object types with qemu-nbd
> via a new --object command line arg. This will be used to supply
> passwords and/or encryption keys to the various block driver
> backends via the recently added 'secret' object type.
>
> # printf letmein > mypasswd.txt
> # qemu-nbd --object secret,id=sec0,file=mypasswd.txt \
> ...other nbd args...
>
> Signed-off-by: Daniel P. Berrange <berra...@redhat.com>
> ---
> qemu-nbd.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
> qemu-nbd.texi | 6 ++++++
> 2 files changed, 60 insertions(+)
>
> diff --git a/qemu-nbd.c b/qemu-nbd.c
> index ede4a54..8e5d36c 100644
> --- a/qemu-nbd.c
> +++ b/qemu-nbd.c
> @@ -23,9 +23,12 @@
> #include "qemu/main-loop.h"
> #include "qemu/sockets.h"
> #include "qemu/error-report.h"
> +#include "qemu/config-file.h"
> #include "block/snapshot.h"
> #include "qapi/util.h"
> #include "qapi/qmp/qstring.h"
> +#include "qapi/opts-visitor.h"
> +#include "qom/object_interfaces.h"
>
> #include <stdarg.h>
> #include <stdio.h>
> @@ -44,6 +47,7 @@
> #define QEMU_NBD_OPT_AIO 2
> #define QEMU_NBD_OPT_DISCARD 3
> #define QEMU_NBD_OPT_DETECT_ZEROES 4
> +#define QEMU_NBD_OPT_OBJECT 5
>
> static NBDExport *exp;
> static int verbose;
> @@ -77,6 +81,9 @@ static void usage(const char *name)
> " -o, --offset=OFFSET offset into the image\n"
> " -P, --partition=NUM only expose partition NUM\n"
> "\n"
> +"General purpose options:\n"
> +" --object type,id=ID,... define an object such as 'secret' for
> providing\n"
> +" passwords and/or encryption keys\n"
> #ifdef __linux__
> "Kernel NBD client support:\n"
> " -c, --connect=DEV connect FILE to the local NBD device DEV\n"
> @@ -374,6 +381,35 @@ static SocketAddress *nbd_build_socket_address(const
> char *sockpath,
> }
>
>
> +static QemuOptsList qemu_object_opts = {
> + .name = "object",
> + .implied_opt_name = "qom-type",
> + .head = QTAILQ_HEAD_INITIALIZER(qemu_object_opts.head),
> + .desc = {
> + { }
> + },
> +};
> +
> +static int object_create(void *opaque, QemuOpts *opts, Error **errp)
> +{
> + Error *err = NULL;
> + OptsVisitor *ov;
> + QDict *pdict;
> +
> + ov = opts_visitor_new(opts);
> + pdict = qemu_opts_to_qdict(opts, NULL);
> +
> + user_creatable_add(pdict, opts_get_visitor(ov), &err);
> + opts_visitor_cleanup(ov);
> + QDECREF(pdict);
> +
> + if (err) {
> + error_propagate(errp, err);
> + return -1;
> + }
> + return 0;
> +}
Hm... This looks very similar to the same function in qemu-img.c. And
actually, vl.c is a bit different, but not too much either. Wouldn't it
make sense to share this code?
Also, now that I compared this to vl.c, there seem to be two differences
compared to the tools: Support for filtering (the tools don't seem to
need this; passing NULL as the callback could skip it) and an additional
obj_unref(obj).
I don't understand much of QOM, so I don't know what the obj_unref() is
for, but I'm wondering whether we need to do the same in the tools. Can
you explain?
> int main(int argc, char **argv)
> {
> BlockBackend *blk;
> @@ -411,6 +447,7 @@ int main(int argc, char **argv)
> { "format", 1, NULL, 'f' },
> { "persistent", 0, NULL, 't' },
> { "verbose", 0, NULL, 'v' },
> + { "object", 1, NULL, QEMU_NBD_OPT_OBJECT },
> { NULL, 0, NULL, 0 }
> };
> int ch;
> @@ -428,6 +465,7 @@ int main(int argc, char **argv)
> Error *local_err = NULL;
> BlockdevDetectZeroesOptions detect_zeroes =
> BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF;
> QDict *options = NULL;
> + QemuOpts *opts;
>
> /* The client thread uses SIGTERM to interrupt the server. A signal
> * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
> @@ -436,6 +474,8 @@ int main(int argc, char **argv)
> memset(&sa_sigterm, 0, sizeof(sa_sigterm));
> sa_sigterm.sa_handler = termsig_handler;
> sigaction(SIGTERM, &sa_sigterm, NULL);
> + module_call_init(MODULE_INIT_QOM);
> + qemu_add_opts(&qemu_object_opts);
Like in qemu-img, I'd prefer directly using the pointer.
Kevin
