| Message ID | 20191017130204.16131-3-kwolf@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add qemu-storage-daemon | expand |
Kevin Wolf <kwolf@redhat.com> writes: > Add a command line option to create user-creatable QOM objects. > > Signed-off-by: Kevin Wolf <kwolf@redhat.com> > --- > qemu-storage-daemon.c | 35 +++++++++++++++++++++++++++++++++++ > 1 file changed, 35 insertions(+) > > diff --git a/qemu-storage-daemon.c b/qemu-storage-daemon.c > index a251dc255c..48d6af43a6 100644 > --- a/qemu-storage-daemon.c > +++ b/qemu-storage-daemon.c > @@ -35,6 +35,8 @@ > #include "qemu/log.h" > #include "qemu/main-loop.h" > #include "qemu/module.h" > +#include "qemu/option.h" > +#include "qom/object_interfaces.h" > > #include "trace/control.h" > > @@ -51,10 +53,26 @@ static void help(void) > " specify tracing options\n" > " -V, --version output version information and exit\n" > "\n" > +" --object <properties> define a QOM object such as 'secret' for\n" > +" passwords and/or encryption keys\n" This is less helpful than qemu-system-FOO's help: -object TYPENAME[,PROP1=VALUE1,...] create a new object of type TYPENAME setting properties in the order they are specified. Note that the 'id' property must be set. These objects are placed in the '/objects' path. > +"\n" > QEMU_HELP_BOTTOM "\n", > error_get_progname()); > } > > +enum { > + OPTION_OBJECT = 256, > +}; > + > +static QemuOptsList qemu_object_opts = { > + .name = "object", > + .implied_opt_name = "qom-type", > + .head = QTAILQ_HEAD_INITIALIZER(qemu_object_opts.head), > + .desc = { > + { } > + }, > +}; > + Note for later: copied from vl.c. > static int process_options(int argc, char *argv[], Error **errp) > { > int c; > @@ -63,6 +81,7 @@ static int process_options(int argc, char *argv[], Error **errp) > > static const struct option long_options[] = { > {"help", no_argument, 0, 'h'}, > + {"object", required_argument, 0, OPTION_OBJECT}, > {"version", no_argument, 0, 'V'}, > {"trace", required_argument, NULL, 'T'}, > {0, 0, 0, 0} > @@ -88,6 +107,22 @@ static int process_options(int argc, char *argv[], Error **errp) > g_free(trace_file); > trace_file = trace_opt_parse(optarg); > break; > + case OPTION_OBJECT: > + { > + QemuOpts *opts; > + const char *type; > + > + opts = qemu_opts_parse(&qemu_object_opts, > + optarg, true, &error_fatal); > + type = qemu_opt_get(opts, "qom-type"); > + > + if (user_creatable_print_help(type, opts)) { > + exit(EXIT_SUCCESS); > + } > + user_creatable_add_opts(opts, &error_fatal); > + qemu_opts_del(opts); > + break; > + } > } > } > if (optind != argc) { PATCH 01 duplicates case QEMU_OPTION_trace pretty much verbatim. Makes sense, as qemu-storage-daemon is basically qemu-system-FOO with "FOO" and most "system" cut away. This patch adds vl.c's case QEMU_OPTION_object in a much simpler form. This is one of my least favourite options, and I'll tell you why below. Let's compare the two versions. vl.c: case QEMU_OPTION_object: opts = qemu_opts_parse_noisily(qemu_find_opts("object"), optarg, true); if (!opts) { exit(1); } break; Further down: qemu_opts_foreach(qemu_find_opts("object"), user_creatable_add_opts_foreach, object_create_initial, &error_fatal); Still further down: qemu_opts_foreach(qemu_find_opts("object"), user_creatable_add_opts_foreach, object_create_delayed, &error_fatal); These are basically for opts in qemu_object_opts { type = qemu_opt_get(opts, "qom-type"); if (type) { if (user_creatable_print_help(type, opts)) { exit(0); } if (!predicate(type)) { continue; } } obj = user_creatable_add_opts(opts, &error_fatal); object_unref(obj); } where predicate(type) is true in exactly one of the two places for each QOM type. The reason for these gymnastics is to create objects at the right time during startup, except there is no right time, but two. Differences: * Options are processed left to right without gymnastics. Getting their order right is the user's problem. I consider this an improvement. * You use &qemu_object_opts instead of qemu_find_opts("object"). Also an improvement. * You use qemu_opts_parse() instead of qemu_opts_parse_noisily(). The latter can print help. I failed to find a case where we lose help compared to qemu-system-FOO. I didn't try very hard. * You neglect to guard user_creatable_print_help(): $ qemu-storage-daemon --object wrong=1,help Segmentation fault (core dumped) * You neglect to object_unref(). I just double-checked the final reference count: it's 2. These bugs shouldn't be hard to fix. At this point you might wonder why I dislike this option so much. vl.c's gymnastics are ugly, but not unusually ugly, and they're gone here. To explain my distaste, I have to go back a little bit. Like quite a few options, --object is paired with QMP command, namely object-add. Both have the same parameters: QOM type, object ID, and additional type-specific object properties. There's a difference, though: object-add wraps the latter in a 'props' object, while --object does not. QAPI schema: { 'command': 'object-add', 'data': {'qom-type': 'str', 'id': 'str', '*props': 'any'} } QAPIfying this part of the CLI isn't easy. The obvious QAPIfied CLI buddy of object-add is incompatible to current --object. That's not a concern for the storage daemon. But it's also ugly, because object-add's nesting of the type-specific properties within @props is. In QMP, it's merely yet another pair of curlies. In the CLI, we get to prefix props. to each type-specific property. If we want to give the storage daemon a QAPIfied command line from the start (and I think we do), we'll have to decide how to address this issue, and possibly more (I'm only at PATCH 02/18). We have a long history of rather careless interface design, and now some of these chickens come home to roost.
Am 07.11.2019 um 21:36 hat Markus Armbruster geschrieben: > Kevin Wolf <kwolf@redhat.com> writes: > > > Add a command line option to create user-creatable QOM objects. > > > > Signed-off-by: Kevin Wolf <kwolf@redhat.com> > > --- > > qemu-storage-daemon.c | 35 +++++++++++++++++++++++++++++++++++ > > 1 file changed, 35 insertions(+) > > > > diff --git a/qemu-storage-daemon.c b/qemu-storage-daemon.c > > index a251dc255c..48d6af43a6 100644 > > --- a/qemu-storage-daemon.c > > +++ b/qemu-storage-daemon.c > > @@ -35,6 +35,8 @@ > > #include "qemu/log.h" > > #include "qemu/main-loop.h" > > #include "qemu/module.h" > > +#include "qemu/option.h" > > +#include "qom/object_interfaces.h" > > > > #include "trace/control.h" > > > > @@ -51,10 +53,26 @@ static void help(void) > > " specify tracing options\n" > > " -V, --version output version information and exit\n" > > "\n" > > +" --object <properties> define a QOM object such as 'secret' for\n" > > +" passwords and/or encryption keys\n" > > This is less helpful than qemu-system-FOO's help: > > -object TYPENAME[,PROP1=VALUE1,...] > create a new object of type TYPENAME setting properties > in the order they are specified. Note that the 'id' > property must be set. These objects are placed in the > '/objects' path. Hm, yes. I took the description from the tools. I can switch to the vl.c one (should the tools, too?). But honestly, neither of the two is enough to tell anyone how to actually use this... Considering how many different objects there are, maybe the best we can do is referring to the man page for details. > > +"\n" > > QEMU_HELP_BOTTOM "\n", > > error_get_progname()); > > } > > > > +enum { > > + OPTION_OBJECT = 256, > > +}; > > + > > +static QemuOptsList qemu_object_opts = { > > + .name = "object", > > + .implied_opt_name = "qom-type", > > + .head = QTAILQ_HEAD_INITIALIZER(qemu_object_opts.head), > > + .desc = { > > + { } > > + }, > > +}; > > + > > Note for later: copied from vl.c. > > > static int process_options(int argc, char *argv[], Error **errp) > > { > > int c; > > @@ -63,6 +81,7 @@ static int process_options(int argc, char *argv[], Error **errp) > > > > static const struct option long_options[] = { > > {"help", no_argument, 0, 'h'}, > > + {"object", required_argument, 0, OPTION_OBJECT}, > > {"version", no_argument, 0, 'V'}, > > {"trace", required_argument, NULL, 'T'}, > > {0, 0, 0, 0} > > @@ -88,6 +107,22 @@ static int process_options(int argc, char *argv[], Error **errp) > > g_free(trace_file); > > trace_file = trace_opt_parse(optarg); > > break; > > + case OPTION_OBJECT: > > + { > > + QemuOpts *opts; > > + const char *type; > > + > > + opts = qemu_opts_parse(&qemu_object_opts, > > + optarg, true, &error_fatal); > > + type = qemu_opt_get(opts, "qom-type"); > > + > > + if (user_creatable_print_help(type, opts)) { > > + exit(EXIT_SUCCESS); > > + } > > + user_creatable_add_opts(opts, &error_fatal); > > + qemu_opts_del(opts); > > + break; > > + } > > } > > } > > if (optind != argc) { > > PATCH 01 duplicates case QEMU_OPTION_trace pretty much verbatim. Makes > sense, as qemu-storage-daemon is basically qemu-system-FOO with "FOO" > and most "system" cut away. > > This patch adds vl.c's case QEMU_OPTION_object in a much simpler form. > This is one of my least favourite options, and I'll tell you why below. > Let's compare the two versions. > > vl.c: > > case QEMU_OPTION_object: > opts = qemu_opts_parse_noisily(qemu_find_opts("object"), > optarg, true); > if (!opts) { > exit(1); > } > break; > > Further down: > > qemu_opts_foreach(qemu_find_opts("object"), > user_creatable_add_opts_foreach, > object_create_initial, &error_fatal); > > Still further down: > > qemu_opts_foreach(qemu_find_opts("object"), > user_creatable_add_opts_foreach, > object_create_delayed, &error_fatal); > > These are basically > > for opts in qemu_object_opts { > type = qemu_opt_get(opts, "qom-type"); > if (type) { > if (user_creatable_print_help(type, opts)) { > exit(0); > } > if (!predicate(type)) { > continue; > } > } > obj = user_creatable_add_opts(opts, &error_fatal); > object_unref(obj); > } > > where predicate(type) is true in exactly one of the two places for each > QOM type. > > The reason for these gymnastics is to create objects at the right time > during startup, except there is no right time, but two. > > Differences: > > * Options are processed left to right without gymnastics. Getting their > order right is the user's problem. I consider this an improvement. > > * You use &qemu_object_opts instead of qemu_find_opts("object"). Also > an improvement. > > * You use qemu_opts_parse() instead of qemu_opts_parse_noisily(). > The latter can print help. I failed to find a case where we lose help > compared to qemu-system-FOO. I didn't try very hard. I tried to reuse that code from qemu_opts_parse_noisily(), until I realised that it wasn't even used for -object. I don't remember the details why qemu_opts_print_help() wasn't even called, but it's obvious that we can't lose anything from it: qemu_object_opts has an empty list of properties, it accepts anything. QemuOpts can't print any useful help when this is all the information it has. > * You neglect to guard user_creatable_print_help(): > > $ qemu-storage-daemon --object wrong=1,help > Segmentation fault (core dumped) Thanks for catching this. (You don't even need the ",help" part, just --object wrong=1 is enough.) > * You neglect to object_unref(). I just double-checked the final > reference count: it's 2. Hm, yes. Weird interface, no caller actually needs this reference. > These bugs shouldn't be hard to fix. > > > At this point you might wonder why I dislike this option so much. > vl.c's gymnastics are ugly, but not unusually ugly, and they're gone > here. To explain my distaste, I have to go back a little bit. > > Like quite a few options, --object is paired with QMP command, namely > object-add. Both have the same parameters: QOM type, object ID, and > additional type-specific object properties. There's a difference, > though: object-add wraps the latter in a 'props' object, while --object > does not. > > QAPI schema: > > { 'command': 'object-add', > 'data': {'qom-type': 'str', 'id': 'str', '*props': 'any'} } > > QAPIfying this part of the CLI isn't easy. > > The obvious QAPIfied CLI buddy of object-add is incompatible to current > --object. That's not a concern for the storage daemon. But it's also > ugly, because object-add's nesting of the type-specific properties > within @props is. In QMP, it's merely yet another pair of curlies. In > the CLI, we get to prefix props. to each type-specific property. > > If we want to give the storage daemon a QAPIfied command line from the > start (and I think we do), we'll have to decide how to address this > issue, and possibly more (I'm only at PATCH 02/18). > > We have a long history of rather careless interface design, and now some > of these chickens come home to roost. On IRC, we discussed last week that we could turn object-add into a 'gen': false command and accept things both as options in props and as flat options on the top level. However, looking at this again, I'm afraid we forgot the context while discussing specifics: How would this be used in a command line parser? We don't start with a QDict here, but with a string. Getting a QDict that could serve as an input to a modified qmp_object_add() would still involve going through QemuOpts for parsing the option string, and then converting it to a QDict. Using a visitor isn't possible with '*props': 'any' and even less so with 'gen': false. So would this really improve things? Or do we have to wait until we have an actual schema for object-add before calling qmp_object_add() actually makes sense? Kevin
Kevin Wolf <kwolf@redhat.com> writes: > Am 07.11.2019 um 21:36 hat Markus Armbruster geschrieben: >> Kevin Wolf <kwolf@redhat.com> writes: >> >> > Add a command line option to create user-creatable QOM objects. >> > >> > Signed-off-by: Kevin Wolf <kwolf@redhat.com> >> > --- >> > qemu-storage-daemon.c | 35 +++++++++++++++++++++++++++++++++++ >> > 1 file changed, 35 insertions(+) >> > >> > diff --git a/qemu-storage-daemon.c b/qemu-storage-daemon.c >> > index a251dc255c..48d6af43a6 100644 >> > --- a/qemu-storage-daemon.c >> > +++ b/qemu-storage-daemon.c >> > @@ -35,6 +35,8 @@ >> > #include "qemu/log.h" >> > #include "qemu/main-loop.h" >> > #include "qemu/module.h" >> > +#include "qemu/option.h" >> > +#include "qom/object_interfaces.h" >> > >> > #include "trace/control.h" >> > >> > @@ -51,10 +53,26 @@ static void help(void) >> > " specify tracing options\n" >> > " -V, --version output version information and exit\n" >> > "\n" >> > +" --object <properties> define a QOM object such as 'secret' for\n" >> > +" passwords and/or encryption keys\n" >> >> This is less helpful than qemu-system-FOO's help: >> >> -object TYPENAME[,PROP1=VALUE1,...] >> create a new object of type TYPENAME setting properties >> in the order they are specified. Note that the 'id' >> property must be set. These objects are placed in the >> '/objects' path. > > Hm, yes. I took the description from the tools. I can switch to the vl.c > one (should the tools, too?). > > But honestly, neither of the two is enough to tell anyone how to > actually use this... Considering how many different objects there are, > maybe the best we can do is referring to the man page for details. For a simple program, --help can provide pretty much the same usage information as the manual page. For a beast like QEMU, that's hopeless. But --help can still serve as a quick reminder of syntax and such. Another argument is consistency: as long as --help shows syntax for the other options, it should probably show syntax for --object, too. We can certainly discuss level of detail. For instance, --blockdev [driver=]<driver>[,node-name=<N>][,discard=ignore|unmap] [,cache.direct=on|off][,cache.no-flush=on|off] [,read-only=on|off][,auto-read-only=on|off] [,force-share=on|off][,detect-zeroes=on|off|unmap] [,driver specific parameters...] configure a block backend is arguably hardly more useful than --blockdev [driver=]<driver>[,node-name=<node-name>][,<prop>=<value>,...] configure a block backend The screen space would arguably be better spend on explaining <driver> and <node-name>. By the way, we should pick *one* way to mark up variable parts, and stick to it. As it is, we have -machine [type=]name[,prop[=value][,...]] -object TYPENAME[,PROP1=VALUE1,...] -blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap] Frankly, this sucks. Let's not mindlessly duplicate the suckage into the storage daemon's help. >> > +"\n" >> > QEMU_HELP_BOTTOM "\n", >> > error_get_progname()); >> > } >> > >> > +enum { >> > + OPTION_OBJECT = 256, >> > +}; >> > + >> > +static QemuOptsList qemu_object_opts = { >> > + .name = "object", >> > + .implied_opt_name = "qom-type", >> > + .head = QTAILQ_HEAD_INITIALIZER(qemu_object_opts.head), >> > + .desc = { >> > + { } >> > + }, >> > +}; >> > + >> >> Note for later: copied from vl.c. >> >> > static int process_options(int argc, char *argv[], Error **errp) >> > { >> > int c; >> > @@ -63,6 +81,7 @@ static int process_options(int argc, char *argv[], Error **errp) >> > >> > static const struct option long_options[] = { >> > {"help", no_argument, 0, 'h'}, >> > + {"object", required_argument, 0, OPTION_OBJECT}, >> > {"version", no_argument, 0, 'V'}, >> > {"trace", required_argument, NULL, 'T'}, >> > {0, 0, 0, 0} >> > @@ -88,6 +107,22 @@ static int process_options(int argc, char *argv[], Error **errp) >> > g_free(trace_file); >> > trace_file = trace_opt_parse(optarg); >> > break; >> > + case OPTION_OBJECT: >> > + { >> > + QemuOpts *opts; >> > + const char *type; >> > + >> > + opts = qemu_opts_parse(&qemu_object_opts, >> > + optarg, true, &error_fatal); >> > + type = qemu_opt_get(opts, "qom-type"); >> > + >> > + if (user_creatable_print_help(type, opts)) { >> > + exit(EXIT_SUCCESS); >> > + } >> > + user_creatable_add_opts(opts, &error_fatal); >> > + qemu_opts_del(opts); >> > + break; >> > + } >> > } >> > } >> > if (optind != argc) { >> >> PATCH 01 duplicates case QEMU_OPTION_trace pretty much verbatim. Makes >> sense, as qemu-storage-daemon is basically qemu-system-FOO with "FOO" >> and most "system" cut away. >> >> This patch adds vl.c's case QEMU_OPTION_object in a much simpler form. >> This is one of my least favourite options, and I'll tell you why below. >> Let's compare the two versions. >> >> vl.c: >> >> case QEMU_OPTION_object: >> opts = qemu_opts_parse_noisily(qemu_find_opts("object"), >> optarg, true); >> if (!opts) { >> exit(1); >> } >> break; >> >> Further down: >> >> qemu_opts_foreach(qemu_find_opts("object"), >> user_creatable_add_opts_foreach, >> object_create_initial, &error_fatal); >> >> Still further down: >> >> qemu_opts_foreach(qemu_find_opts("object"), >> user_creatable_add_opts_foreach, >> object_create_delayed, &error_fatal); >> >> These are basically >> >> for opts in qemu_object_opts { >> type = qemu_opt_get(opts, "qom-type"); >> if (type) { >> if (user_creatable_print_help(type, opts)) { >> exit(0); >> } >> if (!predicate(type)) { >> continue; >> } >> } >> obj = user_creatable_add_opts(opts, &error_fatal); >> object_unref(obj); >> } >> >> where predicate(type) is true in exactly one of the two places for each >> QOM type. >> >> The reason for these gymnastics is to create objects at the right time >> during startup, except there is no right time, but two. >> >> Differences: >> >> * Options are processed left to right without gymnastics. Getting their >> order right is the user's problem. I consider this an improvement. >> >> * You use &qemu_object_opts instead of qemu_find_opts("object"). Also >> an improvement. >> >> * You use qemu_opts_parse() instead of qemu_opts_parse_noisily(). >> The latter can print help. I failed to find a case where we lose help >> compared to qemu-system-FOO. I didn't try very hard. > > I tried to reuse that code from qemu_opts_parse_noisily(), until I > realised that it wasn't even used for -object. What do you mean by "not used"? vl.c: case QEMU_OPTION_object: opts = qemu_opts_parse_noisily(qemu_find_opts("object"), optarg, true); if (!opts) { exit(1); } break; > I don't remember the details why qemu_opts_print_help() wasn't even > called, but it's obvious that we can't lose anything from it: > qemu_object_opts has an empty list of properties, it accepts anything. > QemuOpts can't print any useful help when this is all the information it > has. I see. Do we want to bake that knowledge into main()? I guess your answer would be "we already do, we call user_creatable_print_help()". Shouldn't we do the same in both main()s then? >> * You neglect to guard user_creatable_print_help(): >> >> $ qemu-storage-daemon --object wrong=1,help >> Segmentation fault (core dumped) > > Thanks for catching this. (You don't even need the ",help" part, just > --object wrong=1 is enough.) > >> * You neglect to object_unref(). I just double-checked the final >> reference count: it's 2. > > Hm, yes. Weird interface, no caller actually needs this reference. Feel free to simplify. >> These bugs shouldn't be hard to fix. >> >> >> At this point you might wonder why I dislike this option so much. >> vl.c's gymnastics are ugly, but not unusually ugly, and they're gone >> here. To explain my distaste, I have to go back a little bit. >> >> Like quite a few options, --object is paired with QMP command, namely >> object-add. Both have the same parameters: QOM type, object ID, and >> additional type-specific object properties. There's a difference, >> though: object-add wraps the latter in a 'props' object, while --object >> does not. >> >> QAPI schema: >> >> { 'command': 'object-add', >> 'data': {'qom-type': 'str', 'id': 'str', '*props': 'any'} } >> >> QAPIfying this part of the CLI isn't easy. >> >> The obvious QAPIfied CLI buddy of object-add is incompatible to current >> --object. That's not a concern for the storage daemon. But it's also >> ugly, because object-add's nesting of the type-specific properties >> within @props is. In QMP, it's merely yet another pair of curlies. In >> the CLI, we get to prefix props. to each type-specific property. >> >> If we want to give the storage daemon a QAPIfied command line from the >> start (and I think we do), we'll have to decide how to address this >> issue, and possibly more (I'm only at PATCH 02/18). >> >> We have a long history of rather careless interface design, and now some >> of these chickens come home to roost. > > On IRC, we discussed last week that we could turn object-add into a > 'gen': false command and accept things both as options in props and as > flat options on the top level. ... to get rid of the nesting both for qemu-system-FOO (where we need backward compatibility) and qemu-storage-daemon (where we don't). We can also discuss getting rid of it only for qemu-storage-daemon. > However, looking at this again, I'm afraid we forgot the context while > discussing specifics: How would this be used in a command line parser? > > We don't start with a QDict here, but with a string. Getting a QDict > that could serve as an input to a modified qmp_object_add() would still > involve going through QemuOpts for parsing the option string, and then > converting it to a QDict. Using a visitor isn't possible with '*props': > 'any' and even less so with 'gen': false. > > So would this really improve things? Or do we have to wait until we have > an actual schema for object-add before calling qmp_object_add() actually > makes sense? Good points. qmp_object_add(), hmp_object_add() and vl.c's main() each use their own interface to a common core. QMP command handlers accept arguments specified in the schema as separate C arguments. For qmp_object_add(), that's @qom-type, @id (both strings) and @props (a QDict). It uses user_creatable_add_type() to create an instance of QOM class @qom-type, set QOM properties for @props with a QObject input visitor, insert into the QOM composition tree as directed by @id. This is simply how QMP commands work. They parse JSON text into a QDict, then feed it to the QObject input visitor to convert to native C types. The only slightly unusual thing is that when we feed the QDict to the visitor in the generated qmp_marshal_object_add(), the visitor passes through @props verbatim, because it's of type 'any', leaving the conversion to native C types to the command handler. With 'gen': false, we bypass qmp_marshal_object_add(). qmp_object_add() gets the QDict, and does all the conversion to C types work. Same as now, plus two more visit_type_str() for @qom-type and @id. main() parses the option argument as QemuOpts "monitor". It uses user_creatable_add_opts(), which splits it into @qom-type, @id and @props for user_creatable_add_type(), then calls it with the options visitor. This is how the options visitor wants to be used. We parse a key=value,... string into a QemuOpts, then feed it to the options visitor. When I QAPIfied -blockdev (crudely!), I didn't use the options visitor, because it is by design too limited for the job. I created a new flow instead: parse a key=value,... string into a QDict with keyval_parse(), then feed it to the QObject input visitor. This leads me to the flow I'd like us to try in the storage daemon: parse into a QDict with keyval_parse(), feed to the 'gen': false qmp_object_add(). Does that make some sense? I've glossed over hmp_object_add() so far, because it's tangential to the problem at hand. Just for completeness (and laughs, possibly bitter): HMP command handlers accept arguments specified in .hx as a single QDict. For hmp_object_add(), that's a string parsed as QemuOpts "monitor" converted to QDict. hmp_object_add() converts it right back to QemuOpts "monitor", then uses user_creatable_add_opts(). Ugh! Need I say more?
diff --git a/qemu-storage-daemon.c b/qemu-storage-daemon.c index a251dc255c..48d6af43a6 100644 --- a/qemu-storage-daemon.c +++ b/qemu-storage-daemon.c @@ -35,6 +35,8 @@ #include "qemu/log.h" #include "qemu/main-loop.h" #include "qemu/module.h" +#include "qemu/option.h" +#include "qom/object_interfaces.h" #include "trace/control.h" @@ -51,10 +53,26 @@ static void help(void) " specify tracing options\n" " -V, --version output version information and exit\n" "\n" +" --object <properties> define a QOM object such as 'secret' for\n" +" passwords and/or encryption keys\n" +"\n" QEMU_HELP_BOTTOM "\n", error_get_progname()); } +enum { + OPTION_OBJECT = 256, +}; + +static QemuOptsList qemu_object_opts = { + .name = "object", + .implied_opt_name = "qom-type", + .head = QTAILQ_HEAD_INITIALIZER(qemu_object_opts.head), + .desc = { + { } + }, +}; + static int process_options(int argc, char *argv[], Error **errp) { int c; @@ -63,6 +81,7 @@ static int process_options(int argc, char *argv[], Error **errp) static const struct option long_options[] = { {"help", no_argument, 0, 'h'}, + {"object", required_argument, 0, OPTION_OBJECT}, {"version", no_argument, 0, 'V'}, {"trace", required_argument, NULL, 'T'}, {0, 0, 0, 0} @@ -88,6 +107,22 @@ static int process_options(int argc, char *argv[], Error **errp) g_free(trace_file); trace_file = trace_opt_parse(optarg); break; + case OPTION_OBJECT: + { + QemuOpts *opts; + const char *type; + + opts = qemu_opts_parse(&qemu_object_opts, + optarg, true, &error_fatal); + type = qemu_opt_get(opts, "qom-type"); + + if (user_creatable_print_help(type, opts)) { + exit(EXIT_SUCCESS); + } + user_creatable_add_opts(opts, &error_fatal); + qemu_opts_del(opts); + break; + } } } if (optind != argc) {
Add a command line option to create user-creatable QOM objects. Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- qemu-storage-daemon.c | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+)