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* error: Document Error API usage rulesMarkus Armbruster2020-07-101-6/+46
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This merely codifies existing practice, with one exception: the rule advising against returning void, where existing practice is mixed. When the Error API was created, we adopted the (unwritten) rule to return void when the function returns no useful value on success, unlike GError, which recommends to return true on success and false on error then. When a function returns a distinct error value, say false, a checked call that passes the error up looks like if (!frobnicate(..., errp)) { handle the error... } When it returns void, we need Error *err = NULL; frobnicate(..., &err); if (err) { handle the error... error_propagate(errp, err); } Not only is this more verbose, it also creates an Error object even when @errp is null, &error_abort or &error_fatal. People got tired of the additional boilerplate, and started to ignore the unwritten rule. The result is confusion among developers about the preferred usage. Make the rule advising against returning void official by putting it in writing. This will hopefully reduce confusion. Update the examples accordingly. The remainder of this series will update a substantial amount of code to honor the rule. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Greg Kurz <groug@kaod.org> Message-Id: <20200707160613.848843-4-armbru@redhat.com> [Tweak prose as per advice from Eric]
* error: Improve error.h's big commentMarkus Armbruster2020-07-101-15/+36
| | | | | | | | | | | | | | Add headlines to the big comment. Explain examples for NULL, &error_abort and &error_fatal argument better. Tweak rationale for error_propagate_prepend(). Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20200707160613.848843-3-armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Greg Kurz <groug@kaod.org>
* error: Fix examples in error.h's big commentMarkus Armbruster2020-07-101-2/+14
| | | | | | | | | | | Mark a bad example more clearly. Fix the error_propagate_prepend() example. Add a missing declaration and a second error pileup example. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Greg Kurz <groug@kaod.org> Message-Id: <20200707160613.848843-2-armbru@redhat.com>
* qapi: Only input visitors can actually failMarkus Armbruster2020-04-302-16/+28
| | | | | | | | | | The previous few commits have made this more obvious, and removed the one exception. Time to clarify the documentation, and drop dead error checking. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200424084338.26803-13-armbru@redhat.com>
* qapi: Fix Visitor contract for start_alternate()Markus Armbruster2020-04-301-3/+2Star
| | | | | | | | | | | The contract demands v->start_alternate() for input and dealloc visitors, but visit_start_alternate() actually requires it for input and clone visitors. Fix the contract, and delete superfluous qapi_dealloc_start_alternate(). Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200424084338.26803-8-armbru@redhat.com>
* qapi: Assert incomplete object occurs only in dealloc visitorMarkus Armbruster2020-04-301-0/+5
| | | | | | Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200424084338.26803-7-armbru@redhat.com>
* qapi: Polish prose in visitor.hMarkus Armbruster2020-04-301-50/+54
| | | | | | Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200424084338.26803-6-armbru@redhat.com>
* qapi: Document @errp usage more thoroughly in visitor.hMarkus Armbruster2020-04-301-14/+23
| | | | | | Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200424084338.26803-5-armbru@redhat.com>
* qapi: Fix typo in visit_start_list()'s contractMarkus Armbruster2020-04-301-2/+2
| | | | | | Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200424084338.26803-4-armbru@redhat.com>
* qapi: Fix the virtual walk example in visitor.h's big commentMarkus Armbruster2020-04-301-1/+3
| | | | | | | | | | | Call visit_check_list(). Missed in commit a4a1c70dc7 "qapi: Make input visitors detect unvisited list tails". Drop an irrelevant error_propagate() while there. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200424084338.26803-3-armbru@redhat.com>
* qapi: Belatedly update visitor.h's big comment for QAPI modulesMarkus Armbruster2020-04-301-5/+5
| | | | | | Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200424084338.26803-2-armbru@redhat.com>
* qobject: Eliminate qdict_iter(), use qdict_first(), qdict_next()Markus Armbruster2020-04-301-3/+0Star
| | | | | | | | | | qdict_iter() has just three uses and no test coverage. Replace by qdict_first(), qdict_next() for more concise code and less type punning. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20200415083048.14339-5-armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
* qobject: Eliminate qlist_iter(), use QLIST_FOREACH_ENTRY() insteadMarkus Armbruster2020-04-301-2/+0Star
| | | | | | | | | qlist_iter() has just three uses outside tests/. Replace by QLIST_FOREACH_ENTRY() for more concise code and less type punning. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20200415083048.14339-4-armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
* qobject: Clean up QLIST_FOREACH_ENTRY()Markus Armbruster2020-04-301-4/+4
| | | | | | | | | QLIST_FOREACH_ENTRY() traverses a tail queue manually. Use QTAILQ_FIRST() and QTAILQ_NEXT() instead. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20200415083048.14339-2-armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
* qmp: constify QmpCommand and listMarc-André Lureau2020-03-171-4/+5
| | | | | | | | | | | Since 0b69f6f72ce47a37a749b056b6d5ec64c61f11e8 "qapi: remove qmp_unregister_command()", the command list can be declared const. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Damien Hedde <damien.hedde@greensocs.com> Message-Id: <20200316171824.2319695-1-marcandre.lureau@redhat.com> [Rebased] Signed-off-by: Markus Armbruster <armbru@redhat.com>
* qstring: add qstring_free()Marc-André Lureau2020-01-241-0/+1
| | | | | | | | Similar to g_string_free(), optionally return the underlying char*. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <20200110153039.1379601-10-marcandre.lureau@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* error: make Error **errp const where it is appropriateVladimir Sementsov-Ogievskiy2019-12-181-3/+3
| | | | | | | | | | | | | | | | | Mostly, Error ** is for returning error from the function, so the callee sets it. However these three functions get already filled errp parameter. They don't change the pointer itself, only change the internal state of referenced Error object. So we can make it Error *const * errp, to stress the behavior. It will also help coccinelle script (in future) to distinguish such cases from common errp usage. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20191205174635.18758-4-vsementsov@virtuozzo.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> [Commit message typo fixed] Signed-off-by: Markus Armbruster <armbru@redhat.com>
* qapi: Make visit_next_list()'s comment less confusingMarkus Armbruster2019-09-241-4/+4
| | | | | | | | | | visit_next_list() returns non-null on success, null on failure. The comment's phrasing "until NULL return or error occurs" is needlessly confusing. Scratch the "or error occurs" part. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20190802122325.16520-1-armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
* qapi: Split error.json off common.jsonMarkus Armbruster2019-08-161-1/+1
| | | | | | | | | | | | | | | | | | | In my "build everything" tree, changing a type in qapi/common.json triggers a recompile of some 3600 out of 6600 objects (not counting tests and objects that don't depend on qemu/osdep.h). One common dependency is QapiErrorClass: it's used only in in qapi/error.h, which uses nothing else, and is widely included. Move QapiErrorClass from common.json to new error.json. Touching common.json now recompiles only some 2900 objects. Cc: Eric Blake <eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com> Message-Id: <20190812052359.30071-4-armbru@redhat.com>
* qapi: remove qmp_unregister_command()Marc-André Lureau2019-02-181-1/+0Star
| | | | | | | | | | This command is no longer needed, the schema has compile-time configuration conditions. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20190214152251.2073-16-armbru@redhat.com>
* qapi: Eliminate indirection through qmp_event_get_func_emit()Markus Armbruster2019-01-241-6/+0Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The qapi_event_send_FOO() functions emit events like this: QMPEventFuncEmit emit; emit = qmp_event_get_func_emit(); if (!emit) { return; } qmp = qmp_event_build_dict("FOO"); [put event arguments into @qmp...] emit(QAPI_EVENT_FOO, qmp); The value of qmp_event_get_func_emit() depends only on the program: * In qemu-system-FOO, it's always monitor_qapi_event_queue. * In tests/test-qmp-event, it's always event_test_emit. * In all other programs, it's always null. This is exactly the kind of dependence the linker is supposed to resolve; we don't actually need an indirection. Note that things would fall apart if we linked more than one QAPI schema into a single program: each set of qapi_event_send_FOO() uses its own event enumeration, yet they share a single emit function. Which takes the event enumeration as an argument. Which one if there's more than one? More seriously: how does this work even now? qemu-system-FOO wants QAPIEvent, and passes a function taking that to qmp_event_set_func_emit(). test-qmp-event wants test_QAPIEvent, and passes a function taking that to qmp_event_set_func_emit(). It works by type trickery, of course: typedef void (*QMPEventFuncEmit)(unsigned event, QDict *dict); void qmp_event_set_func_emit(QMPEventFuncEmit emit); QMPEventFuncEmit qmp_event_get_func_emit(void); We use unsigned instead of the enumeration type. Relies on both enumerations boiling down to unsigned, which happens to be true for the compilers we use. Clean this up as follows: * Generate qapi_event_send_FOO() that call PREFIX_qapi_event_emit() instead of the value of qmp_event_set_func_emit(). * Generate a prototype for PREFIX_qapi_event_emit() into qapi-events.h. * PREFIX_ is empty for qapi/qapi-schema.json, and test_ for tests/qapi-schema/qapi-schema-test.json. It's qga_ for qga/qapi-schema.json, and doc-good- for tests/qapi-schema/doc-good.json, but those don't define any events. * Rename monitor_qapi_event_queue() to qapi_event_emit() instead of passing it to qmp_event_set_func_emit(). This takes care of qemu-system-FOO. * Rename event_test_emit() to test_qapi_event_emit() instead of passing it to qmp_event_set_func_emit(). This takes care of tests/test-qmp-event. * Add a qapi_event_emit() that does nothing to stubs/monitor.c. This takes care of all other programs that link code emitting QMP events. * Drop qmp_event_set_func_emit(), qmp_event_get_func_emit(). Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20181218182234.28876-3-armbru@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> [Commit message typos fixed]
* qapi: Rewrite string-input-visitor's integer and list parsingDavid Hildenbrand2018-12-131-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The input visitor has some problems right now, especially - unsigned type "Range" is used to process signed ranges, resulting in inconsistent behavior and ugly/magical code - uint64_t are parsed like int64_t, so big uint64_t values are not supported and error messages are misleading - lists/ranges of int64_t are accepted although no list is parsed and we should rather report an error - lists/ranges are preparsed using int64_t, making it hard to implement uint64_t values or uint64_t lists - types that don't support lists don't bail out - visiting beyond the end of a list is not handled properly - we don't actually parse lists, we parse *sets*: members are sorted, and duplicates eliminated So let's rewrite it by getting rid of usage of the type "Range" and properly supporting lists of int64_t and uint64_t (including ranges of both types), fixing the above mentioned issues. Lists of other types are not supported and will properly report an error. Virtual walks are now supported. Tests have to be fixed up: - Two BUGs were hardcoded that are fixed now - The string-input-visitor now actually returns a parsed list and not an ordered set. Please note that no users/callers have to be fixed up. Candidates using visit_type_uint16List() and friends are: - backends/hostmem.c:host_memory_backend_set_host_nodes() -- Code can deal with duplicates/unsorted lists - numa.c::query_memdev() -- via object_property_get_uint16List(), the list will still be sorted and without duplicates (via host_memory_backend_get_host_nodes()) - qapi-visit.c::visit_type_Memdev_members() - qapi-visit.c::visit_type_NumaNodeOptions_members() - qapi-visit.c::visit_type_RockerOfDpaGroup_members - qapi-visit.c::visit_type_RxFilterInfo_members() -- Not used with string-input-visitor. Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: David Hildenbrand <david@redhat.com> Message-Id: <20181121164421.20780-7-david@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
* error: Fix use of error_prepend() with &error_fatal, &error_abortMarkus Armbruster2018-10-191-0/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | From include/qapi/error.h: * Pass an existing error to the caller with the message modified: * error_propagate(errp, err); * error_prepend(errp, "Could not frobnicate '%s': ", name); Fei Li pointed out that doing error_propagate() first doesn't work well when @errp is &error_fatal or &error_abort: the error_prepend() is never reached. Since I doubt fixing the documentation will stop people from getting it wrong, introduce error_propagate_prepend(), in the hope that it lures people away from using its constituents in the wrong order. Update the instructions in error.h accordingly. Convert existing error_prepend() next to error_propagate to error_propagate_prepend(). If any of these get reached with &error_fatal or &error_abort, the error messages improve. I didn't check whether that's the case anywhere. Cc: Fei Li <fli@suse.com> Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20181017082702.5581-2-armbru@redhat.com>
* scripts: Remove check-qerror.shAlberto Garcia2018-10-191-3/+3
| | | | | | | | | | | | | | | | | | | | qerror.h contains leftovers from the now-defunct QError API. There's only a handful of string macros left, and no one is supposed to add anything else. The check-qerror.sh script was used to make sure that all definitions on the qerror.c and qerror.h files were sorted alphabetically. The former was removed three years ago, and the latter is now in a different location, so the script doesn't even work (as a matter of fact the alphabetical order was broken last time someone added a macro -also in 2015- and no one seemed to notice). There's no point in fixing this script so let's just remove it. The rogue macro is also moved to its correct location. Signed-off-by: Alberto Garcia <berto@igalia.com> Message-Id: <20181017151738.20299-1-berto@igalia.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
* Merge remote-tracking branch 'remotes/armbru/tags/pull-monitor-2018-09-01' ↵Peter Maydell2018-09-241-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | into staging Monitor patches for 2018-09-01 # gpg: Signature made Sat 01 Sep 2018 12:06:52 BST # gpg: using RSA key 3870B400EB918653 # gpg: Good signature from "Markus Armbruster <armbru@redhat.com>" # gpg: aka "Markus Armbruster <armbru@pond.sub.org>" # Primary key fingerprint: 354B C8B3 D7EB 2A6B 6867 4E5F 3870 B400 EB91 8653 * remotes/armbru/tags/pull-monitor-2018-09-01: monitor: no need to save need_resume Revert "qmp: isolate responses into io thread" qmp: constify qmp_is_oob() monitor: consitify qmp_send_response() QDict argument monitor: accept input on resume monitor: simplify monitor_qmp_setup_handlers_bh Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
| * qmp: constify qmp_is_oob()Marc-André Lureau2018-08-301-1/+1
| | | | | | | | | | | | | | Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20180829134043.31706-3-marcandre.lureau@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
* | qapi: Drop qapi_event_send_FOO()'s Error ** argumentPeter Xu2018-08-281-2/+1Star
|/ | | | | | | | | | | | | | | | | | | The generated qapi_event_send_FOO() take an Error ** argument. They can't actually fail, because all they do with the argument is passing it to functions that can't fail: the QObject output visitor, and the @qmp_emit callback, which is either monitor_qapi_event_queue() or event_test_emit(). Drop the argument, and pass &error_abort to the QObject output visitor and @qmp_emit instead. Suggested-by: Eric Blake <eblake@redhat.com> Suggested-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20180815133747.25032-4-peterx@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> [Commit message rewritten, update to qapi-code-gen.txt corrected] Signed-off-by: Markus Armbruster <armbru@redhat.com>
* json: Update references to RFC 7159 to RFC 8259Markus Armbruster2018-08-241-1/+1
| | | | | | | | RFC 8259 (December 2017) obsoletes RFC 7159 (March 2014). Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20180823164025.12553-59-armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
* json: Clean up headersMarkus Armbruster2018-08-243-103/+29Star
| | | | | | | | | | | | | The JSON parser has three public headers, json-lexer.h, json-parser.h, json-streamer.h. They all contain stuff that is of no interest outside qobject/json-*.c. Collect the public interface in include/qapi/qmp/json-parser.h, and everything else in qobject/json-parser-int.h. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180823164025.12553-54-armbru@redhat.com>
* qobject: Drop superfluous includes of qemu-common.hMarkus Armbruster2018-08-241-1/+0Star
| | | | | | Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180823164025.12553-53-armbru@redhat.com>
* json: Make JSONToken opaque outside json-parser.cMarkus Armbruster2018-08-242-7/+4Star
| | | | | | Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180823164025.12553-52-armbru@redhat.com>
* json: Unbox tokens queue in JSONMessageParserMarkus Armbruster2018-08-241-1/+1
| | | | | | Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180823164025.12553-51-armbru@redhat.com>
* json: Fix streamer not to ignore trailing unterminated structuresMarkus Armbruster2018-08-241-0/+1
| | | | | | | | | | | | | | | | | | json_message_process_token() accumulates tokens until it got the sequence of tokens that comprise a single JSON value (it counts curly braces and square brackets to decide). It feeds those token sequences to json_parser_parse(). If a non-empty sequence of tokens remains at the end of the parse, it's silently ignored. check-qjson.c cases unterminated_array(), unterminated_array_comma(), unterminated_dict(), unterminated_dict_comma() demonstrate this bug. Fix as follows. Introduce a JSON_END_OF_INPUT token. When the streamer receives it, it feeds the accumulated tokens to json_parser_parse(). Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180823164025.12553-46-armbru@redhat.com>
* json: Pass lexical errors and limit violations to callbackMarkus Armbruster2018-08-241-3/+0Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The callback to consume JSON values takes QObject *json, Error *err. If both are null, the callback is supposed to make up an error by itself. This sucks. qjson.c's consume_json() neglects to do so, which makes qobject_from_json() null instead of failing. I consider that a bug. The culprit is json_message_process_token(): it passes two null pointers when it runs into a lexical error or a limit violation. Fix it to pass a proper Error object then. Update the callbacks: * monitor.c's handle_qmp_command(): the code to make up an error is now dead, drop it. * qga/main.c's process_event(): lumps the "both null" case together with the "not a JSON object" case. The former is now gone. The error message "Invalid JSON syntax" is misleading for the latter. Improve it to "Input must be a JSON object". * qobject/qjson.c's consume_json(): no update; check-qjson demonstrates qobject_from_json() now sets an error on lexical errors, but still doesn't on some other errors. * tests/libqtest.c's qmp_response(): the Error object is now reliable, so use it to improve the error message. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180823164025.12553-40-armbru@redhat.com>
* json: Treat unwanted interpolation as lexical errorMarkus Armbruster2018-08-241-2/+2
| | | | | | | | | | | | | | | | | | | The JSON parser optionally supports interpolation. The lexer recognizes interpolation tokens unconditionally. The parser rejects them when interpolation is disabled, in parse_interpolation(). However, it neglects to set an error then, which can make json_parser_parse() fail without setting an error. Move the check for unwanted interpolation from the parser's parse_interpolation() into the lexer's finite state machine. When interpolation is disabled, '%' is now handled like any other unexpected character. The next commit will improve how such lexical errors are handled. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180823164025.12553-39-armbru@redhat.com>
* json: Rename token JSON_ESCAPE & friends to JSON_INTERPMarkus Armbruster2018-08-241-1/+1
| | | | | | | | | | | | The JSON parser optionally supports interpolation. The code calls it "escape". Awkward, because it uses the same term for escape sequences within strings. The latter usage is consistent with RFC 8259 "The JavaScript Object Notation (JSON) Data Interchange Format" and ISO C. Call the former "interpolation" instead. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180823164025.12553-38-armbru@redhat.com>
* json: Redesign the callback to consume JSON valuesMarkus Armbruster2018-08-242-4/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The classical way to structure parser and lexer is to have the client call the parser to get an abstract syntax tree, the parser call the lexer to get the next token, and the lexer call some function to get input characters. Another way to structure them would be to have the client feed characters to the lexer, the lexer feed tokens to the parser, and the parser feed abstract syntax trees to some callback provided by the client. This way is more easily integrated into an event loop that dispatches input characters as they arrive. Our JSON parser is kind of between the two. The lexer feeds tokens to a "streamer" instead of a real parser. The streamer accumulates tokens until it got the sequence of tokens that comprise a single JSON value (it counts curly braces and square brackets to decide). It feeds those token sequences to a callback provided by the client. The callback passes each token sequence to the parser, and gets back an abstract syntax tree. I figure it was done that way to make a straightforward recursive descent parser possible. "Get next token" becomes "pop the first token off the token sequence". Drawback: we need to store a complete token sequence. Each token eats 13 + input characters + malloc overhead bytes. Observations: 1. This is not the only way to use recursive descent. If we replaced "get next token" by a coroutine yield, we could do without a streamer. 2. The lexer reports errors by passing a JSON_ERROR token to the streamer. This communicates the offending input characters and their location, but no more. 3. The streamer reports errors by passing a null token sequence to the callback. The (already poor) lexical error information is thrown away. 4. Having the callback receive a token sequence duplicates the code to convert token sequence to abstract syntax tree in every callback. 5. Known bug: the streamer silently drops incomplete token sequences. This commit rectifies 4. by lifting the call of the parser from the callbacks into the streamer. Later commits will address 3. and 5. The lifting removes a bug from qjson.c's parse_json(): it passed a pointer to a non-null Error * in certain cases, as demonstrated by check-qjson.c. json_parser_parse() is now unused. It's a stupid wrapper around json_parser_parse_err(). Drop it, and rename json_parser_parse_err() to json_parser_parse(). Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180823164025.12553-35-armbru@redhat.com>
* json: Have lexer call streamer directlyMarkus Armbruster2018-08-242-10/+6Star
| | | | | | | | | | json_lexer_init() takes the function to process a token as an argument. It's always json_message_process_token(). Makes the code harder to understand for no actual gain. Drop the indirection. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180823164025.12553-34-armbru@redhat.com>
* json: remove useless return value from lexer/parserMarc-André Lureau2018-08-242-4/+4
| | | | | | | | | | | | The lexer always returns 0 when char feeding. Furthermore, none of the caller care about the return value. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <20180326150916.9602-10-marcandre.lureau@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Thomas Huth <thuth@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20180823164025.12553-32-armbru@redhat.com>
* qobject: qobject_from_jsonv() is dangerous, hide it awayMarkus Armbruster2018-08-161-2/+0Star
| | | | | | | | | | | | | qobject_from_jsonv() takes ownership of %p arguments. On failure, we can't generally know whether we failed before or after %p, so ownership becomes indeterminate. To avoid leaks, callers passing %p must terminate on error, e.g. by passing &error_abort. Trap for the unwary; document and give the function internal linkage. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180806065344.7103-11-armbru@redhat.com>
* qobject: New qobject_from_vjsonf_nofail(), qdict_from_vjsonf_nofail()Markus Armbruster2018-08-161-0/+4
| | | | | | | | | | | | Every printf()-like function sooner or later needs its vprintf()-like buddy. The next commit will need qobject_from_jsonf_nofail()'s buddy, and qdict_from_jsonf_nofail()'s buddy will be used later in this series. Add both. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180806065344.7103-8-armbru@redhat.com>
* qobject: Replace qobject_from_jsonf() by qobject_from_jsonf_nofail()Markus Armbruster2018-08-161-2/+4
| | | | | | | | | | | | | | | | | | | | Commit ab45015a968 "qobject: Let qobject_from_jsonf() fail instead of abort" fails to accomplish its stated aim: the function can still abort due to its use of &error_abort. Its rationale for letting it fail is that all remaining users cope fine with failure. Well, they're just fine with aborting, too; it's what they do on failure. Simply reverting the broken commit would bring back the unfortunate asymmetry between qobject_from_jsonf() and qobject_from_jsonv(): one aborts, the other returns null. So also rename it to qobject_from_jsonf_nofail(). Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Thomas Huth <thuth@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180806065344.7103-7-armbru@redhat.com>
* qstring: Fix qstring_from_substr() not to provoke int overflowliujunjie2018-07-281-1/+1
| | | | | | | | | | | | | | | | | | | qstring_from_substr() parameters @start and @end are of type int. blkdebug_parse_filename(), blkverify_parse_filename(), nbd_parse_uri(), and qstring_from_str() pass @end values of type size_t or ptrdiff_t. Values exceeding INT_MAX get truncated, with possibly disastrous results. Such huge substrings seem unlikely, but we found one in a core dump, where "info tlb" executed via QMP's human-monitor-command apparently produced 35 GiB of output. Fix by changing the parameters size_t. Signed-off-by: liujunjie <liujunjie23@huawei.com> Message-Id: <20180724134339.17832-1-liujunjie23@huawei.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
* qmp: Use QDict * instead of QObject * for response objectsMarkus Armbruster2018-07-031-2/+2
| | | | | | | | | By using the more specific type, we get fewer downcasts. The downcasts are safe, but not obviously so, at least not locally. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180703085358.13941-24-armbru@redhat.com>
* qmp: De-duplicate error response buildingMarkus Armbruster2018-07-031-1/+1
| | | | | | | | | | All callers of qmp_build_error_object() duplicate the code to wrap it in a response object. Replace it by qmp_error_response() that captures the duplicated code, including error_free(). Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180703085358.13941-23-armbru@redhat.com>
* qobject: New qdict_from_jsonf_nofail()Markus Armbruster2018-07-031-0/+2
| | | | | | | | | | Many uses of qobject_from_jsonf() convert JSON objects. Create new convenience function qdict_from_jsonf_nofail() that includes the conversion to QDict. The next few commits will put it to use. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180703085358.13941-22-armbru@redhat.com>
* qmp: Don't let malformed in-band commands jump the queueMarkus Armbruster2018-07-031-2/+0Star
| | | | | | | | | | | | | | | | | | handle_qmp_command() reports certain errors right away. This is wrong when OOB is enabled, because the errors can "jump the queue" then, as the previous commit demonstrates. To fix, we need to delay errors until dispatch. Do that for semantic errors, mostly by reverting ill-advised parts of commit cf869d53172 "qmp: support out-of-band (oob) execution". Bonus: doesn't run qmp_dispatch_check_obj() twice, once in handle_qmp_command(), and again in do_qmp_dispatch(). That's also due to commit cf869d53172. The next commit will fix queue jumping for syntax errors. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180703085358.13941-18-armbru@redhat.com>
* qmp qemu-ga: Fix qemu-ga not to accept "control"Markus Armbruster2018-07-031-2/+4
| | | | | | | | | | | | | | | | | | | | | | | Commit cf869d53172 "qmp: support out-of-band (oob) execution" accidentally made qemu-ga accept and ignore "control". Fix that. Out-of-band execution in a monitor that doesn't support it now fails with {"error": {"class": "GenericError", "desc": "QMP input member 'control' is unexpected"}} instead of {"error": {"class": "GenericError", "desc": "Please enable out-of-band first for the session during capabilities negotiation"}} The old description is suboptimal when out-of-band cannot not be enabled, or the command doesn't support out-of-band execution. The new description is a bit unspecific, but it'll do. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180703085358.13941-12-armbru@redhat.com>
* block: Add block-specific QDict headerMax Reitz2018-06-151-17/+0Star
| | | | | | | | | | | | | | | | | | | | | There are numerous QDict functions that have been introduced for and are used only by the block layer. Move their declarations into an own header file to reflect that. While qdict_extract_subqdict() is in fact used outside of the block layer (in util/qemu-config.c), it is still a function related very closely to how the block layer works with nested QDicts, namely by sometimes flattening them. Therefore, its declaration is put into this header as well and util/qemu-config.c includes it with a comment stating exactly which function it needs. Suggested-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <20180509165530.29561-7-mreitz@redhat.com> [Copyright note tweaked, superfluous includes dropped] Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* qapi: introduce new cmd option "allow-preconfig"Igor Mammedov2018-05-301-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | New option will be used to allow commands, which are prepared/need to run, during preconfig state. Other commands that should be able to run in preconfig state, should be amended to not expect machine in initialized state or deal with it. For compatibility reasons, commands that don't use new flag 'allow-preconfig' explicitly are not permitted to run in preconfig state but allowed in all other states like they used to be. Within this patch allow following commands in preconfig state: qmp_capabilities query-qmp-schema query-commands query-command-line-options query-status exit-preconfig to allow qmp connection, basic introspection and moving to the next state. PS: set-numa-node and query-hotpluggable-cpus will be enabled later in a separate patches. Signed-off-by: Igor Mammedov <imammedo@redhat.com> Message-Id: <1526057503-39287-1-git-send-email-imammedo@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> [ehabkost: Changed "since 2.13" to "since 3.0"] Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>