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2017-01-24include: Fix typos found by codespellStefan Weil
Add also a missing parenthesis in a comment. Signed-off-by: Stefan Weil <sw@weilnetz.de> Acked-by: Alistair Francis <alistair.francis@xilinx.com> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2017-01-19error: error_setg_errno(): errno gets preservedSascha Silbe
C11 allows errno to be clobbered by pretty much any library function call, so in general callers need to take care to save errno before calling other functions. However, for error reporting functions this is rather awkward and can make the code on the caller side more complicated than necessary. error_setg_errno() already takes care of preserving errno and some functions rely on that, so just promise that we continue to do so in the future. Signed-off-by: Sascha Silbe <silbe@linux.vnet.ibm.com> Message-Id: <1469611466-31574-1-git-send-email-silbe@linux.vnet.ibm.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-10-25qdict: implement a qdict_crumple method for un-flattening a dictDaniel P. Berrange
The qdict_flatten() method will take a dict whose elements are further nested dicts/lists and flatten them by concatenating keys. The qdict_crumple() method aims to do the reverse, taking a flat qdict, and turning it into a set of nested dicts/lists. It will apply nesting based on the key name, with a '.' indicating a new level in the hierarchy. If the keys in the nested structure are all numeric, it will create a list, otherwise it will create a dict. If the keys are a mixture of numeric and non-numeric, or the numeric keys are not in strictly ascending order, an error will be reported. As an example, a flat dict containing { 'foo.0.bar': 'one', 'foo.0.wizz': '1', 'foo.1.bar': 'two', 'foo.1.wizz': '2' } will get turned into a dict with one element 'foo' whose value is a list. The list elements will each in turn be dicts. { 'foo': [ { 'bar': 'one', 'wizz': '1' }, { 'bar': 'two', 'wizz': '2' } ], } If the key is intended to contain a literal '.', then it must be escaped as '..'. ie a flat dict { 'foo..bar': 'wizz', 'bar.foo..bar': 'eek', 'bar.hello': 'world' } Will end up as { 'foo.bar': 'wizz', 'bar': { 'foo.bar': 'eek', 'hello': 'world' } } The intent of this function is that it allows a set of QemuOpts to be turned into a nested data structure that mirrors the nesting used when the same object is defined over QMP. Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Signed-off-by: Daniel P. Berrange <berrange@redhat.com> Message-Id: <1475246744-29302-3-git-send-email-berrange@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> [Parameter recursive dropped along with its tests; whitespace style touched up] Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-10-25qapi: rename QmpOutputVisitor to QObjectOutputVisitorDaniel P. Berrange
The QmpOutputVisitor has no direct dependency on QMP. It is valid to use it anywhere that one wants a QObject. Rename it to better reflect its functionality as a generic QAPI to QObject converter. The commit before previous renamed the files, this one renames C identifiers. Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Daniel P. Berrange <berrange@redhat.com> Message-Id: <1475246744-29302-6-git-send-email-berrange@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> [Split into file rename and identifier rename] Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-10-25qapi: rename QmpInputVisitor to QObjectInputVisitorDaniel P. Berrange
The QmpInputVisitor has no direct dependency on QMP. It is valid to use it anywhere that one has a QObject. Rename it to better reflect its functionality as a generic QObject to QAPI converter. The previous commit renamed the files, this one renames C identifiers. Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Daniel P. Berrange <berrange@redhat.com> Message-Id: <1475246744-29302-5-git-send-email-berrange@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> [Straightforwardly rebased, split into file and identifier rename] Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-10-25qapi: rename *qmp-*-visitor* to *qobject-*-visitor*Daniel P. Berrange
The QMP visitors have no direct dependency on QMP. It is valid to use them anywhere that one has a QObject. Rename them to better reflect their functionality as a generic QObject to QAPI converter. This is the first of three parts: rename the files. The next two parts will rename C identifiers. The split is necessary to make git rename detection work. Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Daniel P. Berrange <berrange@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> [Split into file and identifier rename, two comments touched up] Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-09-19qapi: Support unregistering QMP commandsMarkus Armbruster
Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <20160912091913.15831-7-marcandre.lureau@redhat.com>
2016-07-13blockjob: Update description of the 'id' fieldAlberto Garcia
The 'id' field of the BlockJob structure will be able to hold any ID, not only a device name. This patch updates the description of that field and the error messages where it is being used. Soon we'll add the ability to set an arbitrary ID when creating a block job. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-07-12Clean up header guards that don't match their file nameMarkus Armbruster
Header guard symbols should match their file name to make guard collisions less likely. Offenders found with scripts/clean-header-guards.pl -vn. Cleaned up with scripts/clean-header-guards.pl, followed by some renaming of new guard symbols picked by the script to better ones. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Richard Henderson <rth@twiddle.net>
2016-07-06sockets: Use new QAPI cloningEric Blake
Rather than rolling our own clone via an expensive conversion in and back out of QObject, use the new clone visitor. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1465490926-28625-15-git-send-email-eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-07-06qapi: Add new clone visitorEric Blake
We have a couple places in the code base that want to deep-clone one QAPI object into another, and they were resorting to serializing the struct out to QObject then reparsing it. A much more efficient version can be done by adding a new clone visitor. Since cloning is still relatively uncommon, expose the use of the new visitor via a QAPI_CLONE() macro that takes care of type-punning the underlying function pointer, rather than generating lots of unused functions for types that won't be cloned. And yes, we're relying on the compiler treating all pointers equally, even though a strict C program cannot portably do so - but we're not the first one in the qemu code base to expect it to work (hello, glib!). The choice of adding a fourth visitor type deserves some explanation. On the surface, the clone visitor is mostly an input visitor (it takes arbitrary input - in this case, another QAPI object - and creates a new QAPI object during the course of the visit). But ever since commit da72ab0 consolidated enum visits based on the visitor type, using VISITOR_INPUT would cause us to run visit_type_str(), even though for cloning there is nothing to do (we just copy the enum value across, without regards to its mapping to strings). Also, since our input happens to be a QAPI object, we can also satisfy the internal checks for VISITOR_OUTPUT. So in the end, I settled with a new VISITOR_CLONE, and chose its value such that many internal checks can use 'v->type & mask', sticking to 'v->type == value' where the difference matters. Note that we can only clone objects (including alternates) and lists, not built-ins or enums. The visitor core hides integer width from the actual visitor (since commit 04e070d), and as long as that's the case, we can't clone top-level integers. Then again, those can always be cloned by direct copy, since they are not objects with deep pointers, so it's no real loss. And restricting cloning to just objects and lists is cleaner than restricting it to non-integers. As such, I documented that the clone visitor is for direct use only by code internal to QAPI, and should not be used on incomplete objects (other than a hack to work around the fact that we allow NULL in place of "" in visit_type_str() in other output visitors). Note that as written, the clone visitor will never fail on a complete object. Scalars (including enums) not at the root of the clone copy just fine with no additional effort while visiting the scalar, by virtue of a g_memdup() each time we push another struct onto the stack. Cloning a string requires deduplication of a pointer, which means it can also provide the guarantee of an input visitor of never producing NULL even when still accepting NULL in place of "" the way the QMP output visitor does. Cloning an 'any' type could be possible by incrementing the QObject refcnt, but it's not obvious whether that is better than implementing a QObject deep clone. So for now, we document it as unsupported, and intentionally omit the .type_any() callback to let a developer know their usage needs implementation. Add testsuite coverage for several different clone situations, to ensure that the code is working. I also tested that valgrind was happy with the test. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1465490926-28625-14-git-send-email-eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-07-06qapi: Add new visit_complete() functionEric Blake
Making each output visitor provide its own output collection function was the only remaining reason for exposing visitor sub-types to the rest of the code base. Add a polymorphic visit_complete() function which is a no-op for input visitors, and which populates an opaque pointer for output visitors. For maximum type-safety, also add a parameter to the output visitor constructors with a type-correct version of the output pointer, and assert that the two uses match. This approach was considered superior to either passing the output parameter only during construction (action at a distance during visit_free() feels awkward) or only during visit_complete() (defeating type safety makes it easier to use incorrectly). Most callers were function-local, and therefore a mechanical conversion; the testsuite was a bit trickier, but the previous cleanup patch minimized the churn here. The visit_complete() function may be called at most once; doing so lets us use transfer semantics rather than duplication or ref-count semantics to get the just-built output back to the caller, even though it means our behavior is not idempotent. Generated code is simplified as follows for events: |@@ -26,7 +26,7 @@ void qapi_event_send_acpi_device_ost(ACP | QDict *qmp; | Error *err = NULL; | QMPEventFuncEmit emit; |- QmpOutputVisitor *qov; |+ QObject *obj; | Visitor *v; | q_obj_ACPI_DEVICE_OST_arg param = { | info |@@ -39,8 +39,7 @@ void qapi_event_send_acpi_device_ost(ACP | | qmp = qmp_event_build_dict("ACPI_DEVICE_OST"); | |- qov = qmp_output_visitor_new(); |- v = qmp_output_get_visitor(qov); |+ v = qmp_output_visitor_new(&obj); | | visit_start_struct(v, "ACPI_DEVICE_OST", NULL, 0, &err); | if (err) { |@@ -55,7 +54,8 @@ void qapi_event_send_acpi_device_ost(ACP | goto out; | } | |- qdict_put_obj(qmp, "data", qmp_output_get_qobject(qov)); |+ visit_complete(v, &obj); |+ qdict_put_obj(qmp, "data", obj); | emit(QAPI_EVENT_ACPI_DEVICE_OST, qmp, &err); and for commands: | { | Error *err = NULL; |- QmpOutputVisitor *qov = qmp_output_visitor_new(); | Visitor *v; | |- v = qmp_output_get_visitor(qov); |+ v = qmp_output_visitor_new(ret_out); | visit_type_AddfdInfo(v, "unused", &ret_in, &err); |- if (err) { |- goto out; |+ if (!err) { |+ visit_complete(v, ret_out); | } |- *ret_out = qmp_output_get_qobject(qov); |- |-out: | error_propagate(errp, err); Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1465490926-28625-13-git-send-email-eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-07-06qmp-output-visitor: Favor new visit_free() functionEric Blake
Now that we have a polymorphic visit_free(), we no longer need qmp_output_visitor_cleanup(); however, we still need to expose the subtype for qmp_output_get_qobject(). Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1465490926-28625-10-git-send-email-eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-07-06string-output-visitor: Favor new visit_free() functionEric Blake
Now that we have a polymorphic visit_free(), we no longer need string_output_visitor_cleanup(); however, we still need to expose the subtype for string_output_get_string(). Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1465490926-28625-9-git-send-email-eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-07-06qmp-input-visitor: Favor new visit_free() functionEric Blake
Now that we have a polymorphic visit_free(), we no longer need qmp_input_visitor_cleanup(); which in turn means we no longer need to return a subtype from qmp_input_visitor_new() nor a public upcast function. Generated code changes to qmp-marshal.c look like: |@@ -52,11 +52,10 @@ void qmp_marshal_add_fd(QDict *args, QOb | { | Error *err = NULL; | AddfdInfo *retval; |- QmpInputVisitor *qiv = qmp_input_visitor_new(QOBJECT(args), true); | Visitor *v; | q_obj_add_fd_arg arg = {0}; | |- v = qmp_input_get_visitor(qiv); |+ v = qmp_input_visitor_new(QOBJECT(args), true); | visit_start_struct(v, NULL, NULL, 0, &err); | if (err) { | goto out; Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1465490926-28625-8-git-send-email-eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-07-06string-input-visitor: Favor new visit_free() functionEric Blake
Now that we have a polymorphic visit_free(), we no longer need string_input_visitor_cleanup(); which in turn means we no longer need to return a subtype from string_input_visitor_new() nor a public upcast function. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1465490926-28625-7-git-send-email-eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-07-06opts-visitor: Favor new visit_free() functionEric Blake
Now that we have a polymorphic visit_free(), we no longer need opts_visitor_cleanup(); which in turn means we no longer need to return a subtype from opts_visitor_new() nor a public upcast function. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1465490926-28625-6-git-send-email-eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-07-06qapi: Add new visit_free() functionEric Blake
Making each visitor provide its own (awkwardly-named) FOO_cleanup() is unusual, when we can instead have a polymorphic visit_free() interface. Over the next few patches, we can use the polymorphic functions to eliminate the need for a FOO_get_visitor() function for accessing specific visitor functionality, once everything can be accessed directly through the Visitor* interfaces. The dealloc visitor is the first one converted to completely use the new entry point, since qapi_dealloc_visitor_cleanup() was the only reason that qapi_dealloc_get_visitor() existed, and only generated and testsuite code was even using it. With the new visit_free() entry point in place, we no longer need to expose the QapiDeallocVisitor subtype through qapi_dealloc_visitor_new(), and can get by with less generated code, with diffs that look like: | void qapi_free_ACPIOSTInfo(ACPIOSTInfo *obj) | { |- QapiDeallocVisitor *qdv; | Visitor *v; | | if (!obj) { | return; | } | |- qdv = qapi_dealloc_visitor_new(); |- v = qapi_dealloc_get_visitor(qdv); |+ v = qapi_dealloc_visitor_new(); | visit_type_ACPIOSTInfo(v, NULL, &obj, NULL); |- qapi_dealloc_visitor_cleanup(qdv); |+ visit_free(v); |} Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1465490926-28625-5-git-send-email-eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-07-06qapi: Add parameter to visit_end_*Eric Blake
Rather than making the dealloc visitor track of stack of pointers remembered during visit_start_* in order to free them during visit_end_*, it's a lot easier to just make all callers pass the same pointer to visit_end_*. The generated code has access to the same pointer, while all other users are doing virtual walks and can pass NULL. The dealloc visitor is then greatly simplified. All three visit_end_*() functions intentionally take a void**, even though the visit_start_*() functions differ between void**, GenericList**, and GenericAlternate**. This is done for several reasons: when doing a virtual walk, passing NULL doesn't care what the type is, but when doing a generated walk, we already have to cast the caller's specific FOO* to call visit_start, while using void** lets us use visit_end without a cast. Also, an upcoming patch will add a clone visitor that wants to use the same implementation for all three visit_end callbacks, which is made easier if all three share the same signature. For visitors with already track per-object state (the QMP visitors via a stack, and the string visitors which do not allow nesting), add an assertion that the caller is indeed passing the same pointer to paired calls. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1465490926-28625-4-git-send-email-eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-07-06qapi: Improve use of qmp/types.hEric Blake
'qjson.h' is not a QObject subtype; include this file directly in .c files that are using it, rather than abusing qmp/types.h for that purpose. Meanwhile, for files that include a list of individual QObject subtypes, it's easier to just use qmp/types.h for that purpose. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1465490926-28625-2-git-send-email-eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-05-26migration: add reporting of errors for outgoing migrationDaniel P. Berrange
Currently if an application initiates an outgoing migration, it may or may not, get an error reported back on failure. If the error occurs synchronously to the 'migrate' command execution, the client app will see the error message. This is the case for DNS lookup failures. If the error occurs asynchronously to the monitor command though, the error will be thrown away and the client left guessing about what went wrong. This is the case for failure to connect to the TCP server (eg due to wrong port, or firewall rules, or other similar errors). In the future we'll be adding more scope for errors to happen asynchronously with the TLS protocol handshake. TLS errors are hard to diagnose even when they are well reported, so discarding errors entirely will make it impossible to debug TLS connection problems. Management apps which do migration are already using 'query-migrate' / 'info migrate' to check up on progress of background migration operations and to see their end status. This is a fine place to also include the error message when things go wrong. This patch thus adds an 'error-desc' field to the MigrationInfo struct, which will be populated when the 'status' is set to 'failed': (qemu) migrate -d tcp:localhost:9001 (qemu) info migrate capabilities: xbzrle: off rdma-pin-all: off auto-converge: off zero-blocks: off compress: off events: off x-postcopy-ram: off Migration status: failed (Error connecting to socket: Connection refused) total time: 0 milliseconds In the HMP, when doing non-detached migration, it is also possible to display this error message directly to the app. (qemu) migrate tcp:localhost:9001 Error connecting to socket: Connection refused Or with QMP { "execute": "query-migrate", "arguments": {} } { "return": { "status": "failed", "error-desc": "address resolution failed for myhost:9000: No address associated with hostname" } } Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Daniel P. Berrange <berrange@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Message-Id: <1461751518-12128-11-git-send-email-berrange@redhat.com> Signed-off-by: Amit Shah <amit.shah@redhat.com>
2016-05-12qapi: Change visit_type_FOO() to no longer return partial objectsEric Blake
Returning a partial object on error is an invitation for a careless caller to leak memory. We already fixed things in an earlier patch to guarantee NULL if visit_start fails ("qapi: Guarantee NULL obj on input visitor callback error"), but that does not help the case where visit_start succeeds but some other failure happens before visit_end, such that we leak a partially constructed object outside visit_type_FOO(). As no one outside the testsuite was actually relying on these semantics, it is cleaner to just document and guarantee that ALL pointer-based visit_type_FOO() functions always leave a safe value in *obj during an input visitor (either the new object on success, or NULL if an error is encountered), so callers can now unconditionally use qapi_free_FOO() to clean up regardless of whether an error occurred. The decision is done by adding visit_is_input(), then updating the generated code to check if additional cleanup is needed based on the type of visitor in use. Note that we still leave *obj unchanged after a scalar-based visit_type_FOO(); I did not feel like auditing all uses of visit_type_Enum() to see if the callers would tolerate a specific sentinel value (not to mention having to decide whether it would be better to use 0 or ENUM__MAX as that sentinel). Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1461879932-9020-25-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-05-12qapi: Simplify semantics of visit_next_list()Eric Blake
The semantics of the list visit are somewhat baroque, with the following pseudocode when FooList is used: start() for (prev = head; cur = next(prev); prev = &cur) { visit(&cur->value) } Note that these semantics (advance before visit) requires that the first call to next() return the list head, while all other calls return the next element of the list; that is, every visitor implementation is required to track extra state to decide whether to return the input as-is, or to advance. It also requires an argument of 'GenericList **' to next(), solely because the first iteration might need to modify the caller's GenericList head, so that all other calls have to do a layer of dereferencing. Thankfully, we only have two uses of list visits in the entire code base: one in spapr_drc (which completely avoids visit_next_list(), feeding in integers from a different source than uint8List), and one in qapi-visit.py. That is, all other list visitors are generated in qapi-visit.c, and share the same paradigm based on a qapi FooList type, so we can refactor how lists are laid out with minimal churn among clients. We can greatly simplify things by hoisting the special case into the start() routine, and flipping the order in the loop to visit before advance: start(head) for (tail = *head; tail; tail = next(tail)) { visit(&tail->value) } With the simpler semantics, visitors have less state to track, the argument to next() is reduced to 'GenericList *', and it also becomes obvious whether an input visitor is allocating a FooList during visit_start_list() (rather than the old way of not knowing if an allocation happened until the first visit_next_list()). As a minor drawback, we now allocate in two functions instead of one, and have to pass the size to both functions (unless we were to tweak the input visitors to cache the size to start_list for reuse during next_list, but that defeats the goal of less visitor state). The signature of visit_start_list() is chosen to match visit_start_struct(), with the new parameters after 'name'. The spapr_drc case is a virtual visit, done by passing NULL for list, similarly to how NULL is passed to visit_start_struct() when a qapi type is not used in those visits. It was easy to provide these semantics for qmp-output and dealloc visitors, and a bit harder for qmp-input (several prerequisite patches refactored things to make this patch straightforward). But it turned out that the string and opts visitors munge enough other state during visit_next_list() to make it easier to just document and require a GenericList visit for now; an assertion will remind us to adjust things if we need the semantics in the future. Several pre-requisite cleanup patches made the reshuffling of the various visitors easier; particularly the qmp input visitor. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1461879932-9020-24-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-05-12qapi: Split visit_end_struct() into piecesEric Blake
As mentioned in previous patches, we want to call visit_end_struct() functions unconditionally, so that visitors can release resources tied up since the matching visit_start_struct() without also having to worry about error priority if more than one error occurs. Even though error_propagate() can be safely used to ignore a second error during cleanup caused by a first error, it is simpler if the cleanup cannot set an error. So, split out the error checking portion (basically, input visitors checking for unvisited keys) into a new function visit_check_struct(), which can be safely skipped if any earlier errors are encountered, and leave the cleanup portion (which never fails, but must be called unconditionally if visit_start_struct() succeeded) in visit_end_struct(). Generated code in qapi-visit.c has diffs resembling: |@@ -59,10 +59,12 @@ void visit_type_ACPIOSTInfo(Visitor *v, | goto out_obj; | } | visit_type_ACPIOSTInfo_members(v, obj, &err); |- error_propagate(errp, err); |- err = NULL; |+ if (err) { |+ goto out_obj; |+ } |+ visit_check_struct(v, &err); | out_obj: |- visit_end_struct(v, &err); |+ visit_end_struct(v); | out: and in qapi-event.c: @@ -47,7 +47,10 @@ void qapi_event_send_acpi_device_ost(ACP | goto out; | } | visit_type_q_obj_ACPI_DEVICE_OST_arg_members(v, &param, &err); |- visit_end_struct(v, err ? NULL : &err); |+ if (!err) { |+ visit_check_struct(v, &err); |+ } |+ visit_end_struct(v); | if (err) { | goto out; Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1461879932-9020-20-git-send-email-eblake@redhat.com> [Conflict with a doc fixup resolved] Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-05-12qapi: Add visit_type_null() visitorEric Blake
Right now, qmp-output-visitor happens to produce a QNull result if nothing is actually visited between the creation of the visitor and the request for the resulting QObject. A stronger protocol would require that a QMP output visit MUST visit something. But to still be able to produce a JSON 'null' output, we need a new visitor function that states our intentions. Yes, we could say that such a visit must go through visit_type_any(), but that feels clunky. So this patch introduces the new visit_type_null() interface and its no-op interface in the dealloc visitor, and stubs in the qmp visitors (the next patch will finish the implementation). For the visitors that will not implement the callback, document the situation. The code in qapi-visit-core unconditionally dereferences the callback pointer, so that a segfault will inform a developer if they need to implement the callback for their choice of visitor. Note that JSON has a primitive null type, with the single value null; likewise with the QNull type for QObject; but for QAPI, we just have the 'null' value without a null type. We may eventually want to add more support in QAPI for null (most likely, we'd use it via an alternate type that permits 'null' or an object); but we'll create that usage when we need it. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1461879932-9020-15-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-05-12qapi: Document visitor interfaces, add assertionsEric Blake
The visitor interface for mapping between QObject/QemuOpts/string and QAPI is scandalously under-documented, making changes to visitor core, individual visitors, and users of visitors difficult to coordinate. Among other questions: when is it safe to pass NULL, vs. when a string must be provided; which visitors implement which callbacks; the difference between concrete and virtual visits. Correct this by retrofitting proper contracts, and document where some of the interface warts remain (for example, we may want to modify visit_end_* to require the same 'obj' as the visit_start counterpart, so the dealloc visitor can be simplified). Later patches in this series will tackle some, but not all, of these warts. Add assertions to (partially) enforce the contract. Some of these were only made possible by recent cleanup commits. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1461879932-9020-13-git-send-email-eblake@redhat.com> [Doc fix from Eric squashed in] Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-05-12qapi: Consolidate QMP input visitor creationEric Blake
Rather than having two separate ways to create a QMP input visitor, where the safer approach has the more verbose name, it is better to consolidate things into a single function where the caller must explicitly choose whether to be strict or to ignore excess input. This patch is the strictly mechanical conversion; the next patch will then audit which uses can be made stricter. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1461879932-9020-6-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-05-12qmp: Drop dead command->typeEric Blake
Ever since QMP was first added back in commit 43c20a43, we have never had any QmpCommandType other than QCT_NORMAL. It's pointless to carry around the cruft. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1461879932-9020-4-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-05-12qapi-visit: Add visitor.type classificationEric Blake
We have three classes of QAPI visitors: input, output, and dealloc. Currently, all implementations of these visitors have one thing in common based on their visitor type: the implementation used for the visit_type_enum() callback. But since we plan to add more such common behavior, in relation to documenting and further refining the semantics, it makes more sense to have the visitor implementations advertise which class they belong to, so the common qapi-visit-core code can use that information in multiple places. A later patch will better document the types of visitors directly in visitor.h. For this patch, knowing the class of a visitor implementation lets us make input_type_enum() and output_type_enum() become static functions, by replacing the callback function Visitor.type_enum() with the simpler enum member Visitor.type. Share a common assertion in qapi-visit-core as part of the refactoring. Move comments in opts-visitor.c to match the refactored layout. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1461879932-9020-2-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-03-22Use scripts/clean-includes to drop redundant qemu/typedefs.hMarkus Armbruster
Re-run scripts/clean-includes to apply the previous commit's corrections and updates. Besides redundant qemu/typedefs.h, this only finds a redundant config-host.h include in ui/egl-helpers.c. No idea how that escaped the previous runs. Some manual whitespace trimming around dropped includes squashed in. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-22include/qemu/osdep.h: Don't include qapi/error.hMarkus Armbruster
Commit 57cb38b included qapi/error.h into qemu/osdep.h to get the Error typedef. Since then, we've moved to include qemu/osdep.h everywhere. Its file comment explains: "To avoid getting into possible circular include dependencies, this file should not include any other QEMU headers, with the exceptions of config-host.h, compiler.h, os-posix.h and os-win32.h, all of which are doing a similar job to this file and are under similar constraints." qapi/error.h doesn't do a similar job, and it doesn't adhere to similar constraints: it includes qapi-types.h. That's in excess of 100KiB of crap most .c files don't actually need. Add the typedef to qemu/typedefs.h, and include that instead of qapi/error.h. Include qapi/error.h in .c files that need it and don't get it now. Include qapi-types.h in qom/object.h for uint16List. Update scripts/clean-includes accordingly. Update it further to match reality: replace config.h by config-target.h, add sysemu/os-posix.h, sysemu/os-win32.h. Update the list of includes in the qemu/osdep.h comment quoted above similarly. This reduces the number of objects depending on qapi/error.h from "all of them" to less than a third. Unfortunately, the number depending on qapi-types.h shrinks only a little. More work is needed for that one. Signed-off-by: Markus Armbruster <armbru@redhat.com> [Fix compilation without the spice devel packages. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-17qapi: Drop QERR_UNKNOWN_BLOCK_FORMAT_FEATUREMax Reitz
Just specifying a custom string is simpler in basically all places that used it, and in addition, specifying the BB or node name is something we generally do not do in other error messages when opening a BDS, so we should not do it here. This changes the output for iotest 036 (to the better, in my opinion), so the reference output needs to be changed accordingly. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-02-23include: Clean up includesPeter Maydell
Clean up includes so that osdep.h is included first and headers which it implies are not included manually. This commit was created with scripts/clean-includes. NB: If this commit breaks compilation for your out-of-tree patchseries or fork, then you need to make sure you add #include "qemu/osdep.h" to any new .c files that you have. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Eric Blake <eblake@redhat.com>
2016-02-19qapi: Change visit_start_implicit_struct to visit_start_alternateEric Blake
After recent changes, the only remaining use of visit_start_implicit_struct() is for allocating the space needed when visiting an alternate. Since the term 'implicit struct' is hard to explain, rename the function to its current usage. While at it, we can merge the functionality of visit_get_next_type() into the same function, making it more like visit_start_struct(). Generated code is now slightly smaller: | { | Error *err = NULL; | |- visit_start_implicit_struct(v, (void**) obj, sizeof(BlockdevRef), &err); |+ visit_start_alternate(v, name, (GenericAlternate **)obj, sizeof(**obj), |+ true, &err); | if (err) { | goto out; | } |- visit_get_next_type(v, name, &(*obj)->type, true, &err); |- if (err) { |- goto out_obj; |- } | switch ((*obj)->type) { | case QTYPE_QDICT: | visit_start_struct(v, name, NULL, 0, &err); ... | } |-out_obj: |- visit_end_implicit_struct(v); |+ visit_end_alternate(v); | out: | error_propagate(errp, err); | } Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1455778109-6278-16-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-02-19qapi: Don't box branches of flat unionsEric Blake
There's no reason to do two malloc's for a flat union; let's just inline the branch struct directly into the C union branch of the flat union. Surprisingly, fewer clients were actually using explicit references to the branch types in comparison to the number of flat unions thus modified. This lets us reduce the hack in qapi-types:gen_variants() added in the previous patch; we no longer need to distinguish between alternates and flat unions. The change to unboxed structs means that u.data (added in commit cee2dedb) is now coincident with random fields of each branch of the flat union, whereas beforehand it was only coincident with pointers (since all branches of a flat union have to be objects). Note that this was already the case for simple unions - but there we got lucky. Remember, visit_start_union() blindly returns true for all visitors except for the dealloc visitor, where it returns the value !!obj->u.data, and that this result then controls whether to proceed with the visit to the variant. Pre-patch, this meant that flat unions were testing whether the boxed pointer was still NULL, and thereby skipping visit_end_implicit_struct() and avoiding a NULL dereference if the pointer had not been allocated. The same was true for simple unions where the current branch had pointer type, except there we bypassed visit_type_FOO(). But for simple unions where the current branch had scalar type, the contents of that scalar meant that the decision to call visit_type_FOO() was data-dependent - the reason we got lucky there is that visit_type_FOO() for all scalar types in the dealloc visitor is a no-op (only the pointer variants had anything to free), so it did not matter whether the dealloc visit was skipped. But with this patch, we would risk leaking memory if we could skip a call to visit_type_FOO_fields() based solely on a data-dependent decision. But notice: in the dealloc visitor, visit_type_FOO() already handles a NULL obj - it was only the visit_type_implicit_FOO() that was failing to check for NULL. And now that we have refactored things to have the branch be part of the parent struct, we no longer have a separate pointer that can be NULL in the first place. So we can just delete the call to visit_start_union() altogether, and blindly visit the branch type; there is no change in behavior except to the dealloc visitor, where we now unconditionally visit the branch, but where that visit is now always safe (for a flat union, we can no longer dereference NULL, and for a simple union, visit_type_FOO() was already safely handling NULL on pointer types). Unfortunately, simple unions are not as easy to switch to unboxed layout; because we are special-casing the hidden implicit type with a single 'data' member, we really DO need to keep calling another layer of visit_start_struct(), with a second malloc; although there are some cleanups planned for simple unions in later patches. visit_start_union() and gen_visit_implicit_struct() are now unused. Drop them. Note that after this patch, the only remaining use of visit_start_implicit_struct() is for alternate types; the next patch will do further cleanup based on that fact. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1455778109-6278-14-git-send-email-eblake@redhat.com> [Dead code deletion squashed in, commit message updated accordingly] Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-02-19qapi: Adjust layout of FooList typesEric Blake
By sticking the next pointer first, we don't need a union with 64-bit padding for smaller types. On 32-bit platforms, this can reduce the size of uint8List from 16 bytes (or 12, depending on whether 64-bit ints can tolerate 4-byte alignment) down to 8. It has no effect on 64-bit platforms (where alignment still dictates a 16-byte struct); but fewer anonymous unions is still a win in my book. It requires visit_next_list() to gain a size parameter, to know what size element to allocate; comparable to the size parameter of visit_start_struct(). I debated about going one step further, to allow for fewer casts, by doing: typedef GenericList GenericList; struct GenericList { GenericList *next; }; struct FooList { GenericList base; Foo *value; }; so that you convert to 'GenericList *' by '&foolist->base', and back by 'container_of(generic, GenericList, base)' (as opposed to the existing '(GenericList *)foolist' and '(FooList *)generic'). But doing that would require hoisting the declaration of GenericList prior to inclusion of qapi-types.h, rather than its current spot in visitor.h; it also makes iteration a bit more verbose through 'foolist->base.next' instead of 'foolist->next'. Note that for lists of objects, the 'value' payload is still hidden behind a boxed pointer. Someday, it would be nice to do: struct FooList { FooList *next; Foo value; }; for one less level of malloc for each list element. This patch is a step in that direction (now that 'next' is no longer at a fixed non-zero offset within the struct, we can store more than just a pointer's-worth of data as the value payload), but the actual conversion would be a task for another series, as it will touch a lot of code. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1455778109-6278-10-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-02-09Merge remote-tracking branch 'remotes/armbru/tags/pull-error-2016-02-09' ↵Peter Maydell
into staging Error reporting patches for 2016-02-09 # gpg: Signature made Tue 09 Feb 2016 12:38:33 GMT using RSA key ID EB918653 # gpg: Good signature from "Markus Armbruster <armbru@redhat.com>" # gpg: aka "Markus Armbruster <armbru@pond.sub.org>" * remotes/armbru/tags/pull-error-2016-02-09: HACKING: Add a section on error handling and reporting error: Improve documentation some more Use error_fatal to simplify obvious fatal errors (again) Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2016-02-09error: Improve documentation some moreMarkus Armbruster
Don't claim error_report_err() always reports to stderr. It actually reports to the current monitor when we have one. Clarify intended use of error_abort and error_fatal. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <1454522628-28294-2-git-send-email-armbru@redhat.com> Reviewed-by: Lluís Vilanova <vilanova@ac.upc.edu>
2016-02-08qapi: Drop unused error argument for list and implicit structEric Blake
No backend was setting an error when ending the visit of a list or implicit struct, or when moving to the next list node. Make the callers a bit easier to follow by making this a part of the contract, and removing the errp argument - callers can then unconditionally end an object as part of cleanup without having to think about whether a second error is dominated by a first, because there is no second error. A later patch will then tackle the larger task of splitting visit_end_struct(), which can indeed set an error. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1454075341-13658-24-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-02-08qapi: Drop unused 'kind' for struct/enum visitEric Blake
visit_start_struct() and visit_type_enum() had a 'kind' argument that was usually set to either the stringized version of the corresponding qapi type name, or to NULL (although some clients didn't even get that right). But nothing ever used the argument. It's even hard to argue that it would be useful in a debugger, as a stack backtrace also tells which type is being visited. Therefore, drop the 'kind' argument as dead. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <1454075341-13658-22-git-send-email-eblake@redhat.com> [Harmless rebase mistake cleaned up] Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-02-08qapi: Swap 'name' in visit_* callbacks to match public APIEric Blake
As explained in the previous patches, matching argument order of 'name, &value' to JSON's "name":value makes sense. However, while the last two patches were easy with Coccinelle, I ended up doing this one all by hand. Now all the visitor callbacks match the main interface. The compiler is able to enforce that all clients match the changed interface in visitor-impl.h, even where two pointers are being swapped, because only one of the two pointers is const (if that were not the case, then C's looseness on treating 'char *' like 'void *' would have made review a bit harder). Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <1454075341-13658-21-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-02-08qapi: Swap visit_* arguments for consistent 'name' placementEric Blake
JSON uses "name":value, but many of our visitor interfaces were called with visit_type_FOO(v, &value, name, errp). This can be a bit confusing to have to mentally swap the parameter order to match JSON order. It's particularly bad for visit_start_struct(), where the 'name' parameter is smack in the middle of the otherwise-related group of 'obj, kind, size' parameters! It's time to do a global swap of the parameter ordering, so that the 'name' parameter is always immediately after the Visitor argument. Additional reason in favor of the swap: the existing include/qjson.h prefers listing 'name' first in json_prop_*(), and I have plans to unify that file with the qapi visitors; listing 'name' first in qapi will minimize churn to the (admittedly few) qjson.h clients. Later patches will then fix docs, object.h, visitor-impl.h, and those clients to match. Done by first patching scripts/qapi*.py by hand to make generated files do what I want, then by running the following Coccinelle script to affect the rest of the code base: $ spatch --sp-file script `git grep -l '\bvisit_' -- '**/*.[ch]'` I then had to apply some touchups (Coccinelle insisted on TAB indentation in visitor.h, and botched the signature of visit_type_enum() by rewriting 'const char *const strings[]' to the syntactically invalid 'const char*const[] strings'). The movement of parameters is sufficient to provoke compiler errors if any callers were missed. // Part 1: Swap declaration order @@ type TV, TErr, TObj, T1, T2; identifier OBJ, ARG1, ARG2; @@ void visit_start_struct -(TV v, TObj OBJ, T1 ARG1, const char *name, T2 ARG2, TErr errp) +(TV v, const char *name, TObj OBJ, T1 ARG1, T2 ARG2, TErr errp) { ... } @@ type bool, TV, T1; identifier ARG1; @@ bool visit_optional -(TV v, T1 ARG1, const char *name) +(TV v, const char *name, T1 ARG1) { ... } @@ type TV, TErr, TObj, T1; identifier OBJ, ARG1; @@ void visit_get_next_type -(TV v, TObj OBJ, T1 ARG1, const char *name, TErr errp) +(TV v, const char *name, TObj OBJ, T1 ARG1, TErr errp) { ... } @@ type TV, TErr, TObj, T1, T2; identifier OBJ, ARG1, ARG2; @@ void visit_type_enum -(TV v, TObj OBJ, T1 ARG1, T2 ARG2, const char *name, TErr errp) +(TV v, const char *name, TObj OBJ, T1 ARG1, T2 ARG2, TErr errp) { ... } @@ type TV, TErr, TObj; identifier OBJ; identifier VISIT_TYPE =~ "^visit_type_"; @@ void VISIT_TYPE -(TV v, TObj OBJ, const char *name, TErr errp) +(TV v, const char *name, TObj OBJ, TErr errp) { ... } // Part 2: swap caller order @@ expression V, NAME, OBJ, ARG1, ARG2, ERR; identifier VISIT_TYPE =~ "^visit_type_"; @@ ( -visit_start_struct(V, OBJ, ARG1, NAME, ARG2, ERR) +visit_start_struct(V, NAME, OBJ, ARG1, ARG2, ERR) | -visit_optional(V, ARG1, NAME) +visit_optional(V, NAME, ARG1) | -visit_get_next_type(V, OBJ, ARG1, NAME, ERR) +visit_get_next_type(V, NAME, OBJ, ARG1, ERR) | -visit_type_enum(V, OBJ, ARG1, ARG2, NAME, ERR) +visit_type_enum(V, NAME, OBJ, ARG1, ARG2, ERR) | -VISIT_TYPE(V, OBJ, NAME, ERR) +VISIT_TYPE(V, NAME, OBJ, ERR) ) Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <1454075341-13658-19-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-02-08qapi: Consolidate visitor small integer callbacksEric Blake
Commit 4e27e819 introduced optional visitor callbacks for all sorts of int types, but no visitor has supplied any of the callbacks for sizes less than 64 bits. In other words, the generic implementation based on using type_[u]int64() followed by bounds-checking works just fine. In the interest of simplicity, it's easier to make the visitor callback interface not have to worry about the other sizes. Adding some helper functions minimizes the boilerplate required to correct FIXMEs added earlier with regards to questionable reuse of errp, particularly now that we can guarantee from a single file audit that value is unchanged if an error is set. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <1454075341-13658-16-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-02-08qapi: Make all visitors supply uint64 callbacksEric Blake
Our qapi visitor contract supports multiple integer visitors, but left the type_uint64 visitor as optional (falling back on type_int64); which in turn can lead to awkward behavior with numbers larger than INT64_MAX (the user has to be aware of twos complement, and deal with negatives). This patch does not address the disparity in handling large values as negatives. It merely moves the fallback from uint64 to int64 from the visitor core to the visitors, where the issue can actually be fixed, by implementing the missing type_uint64() callbacks on top of the respective type_int64() callbacks, and with a FIXME comment explaining why that's wrong. With that done, we now have a type_uint64() callback in every driver, so we can make it mandatory from the core. And although the type_int64() callback can cover the entire valid range of type_uint{8,16,32} on valid user input, using type_uint64() to avoid mixed signedness makes more sense. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1454075341-13658-15-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-02-08qapi: Prefer type_int64 over type_int in visitorsEric Blake
The qapi builtin type 'int' is basically shorthand for the type 'int64'. In fact, since no visitor was providing the optional type_int64() callback, visit_type_int64() was just always falling back to type_int(), cementing the equivalence between the types. However, some visitors are providing a type_uint64() callback. For purposes of code consistency, it is nicer if all visitors use the paired type_int64/type_uint64 names rather than the mismatched type_int/type_uint64. So this patch just renames the signed int callbacks in place, dropping the type_int() callback as redundant, and a later patch will focus on the unsigned int callbacks. Add some FIXMEs to questionable reuse of errp in code touched by the rename, while at it (the reuse works as long as the callbacks don't modify value when setting an error, but it's not a good example to set) - a later patch will then fix those. No change in functionality here, although further cleanups are in the pipeline. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1454075341-13658-14-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-02-08qapi-visit: Kill unused visit_end_union()Eric Blake
The generated code can call visit_end_union() without having called visit_start_union(). Example: if (!*obj) { goto out_obj; } visit_type_CpuInfoBase_fields(v, (CpuInfoBase **)obj, &err); if (err) { goto out_obj; // if we go from here... } if (!visit_start_union(v, !!(*obj)->u.data, &err) || err) { goto out_obj; } switch ((*obj)->arch) { [...] } out_obj: // ... then *obj is true, and ... error_propagate(errp, err); err = NULL; if (*obj) { // we end up here visit_end_union(v, !!(*obj)->u.data, &err); } error_propagate(errp, err); Harmless only because no visitor implements end_union(). Clean it up anyway, by deleting the function as useless. Messed up since we have visit_end_union (commit cee2ded). Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <1453902888-20457-3-git-send-email-armbru@redhat.com> [expand scope of patch to delete rather than repair] Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1454075341-13658-13-git-send-email-eblake@redhat.com>
2016-01-13error: New error_prepend(), error_reportf_err()Markus Armbruster
Instead of simply propagating an error verbatim, we sometimes want to add to its message, like this: frobnicate(arg, &err); error_setg(errp, "Can't frobnicate %s: %s", arg, error_get_pretty(err)); error_free(err); This is suboptimal, because it loses err's hint (if any). Moreover, when errp is &error_abort or is subsequently propagated to &error_abort, the abort message points to the place where we last added to the error, not to the place where it originated. To avoid these issues, provide means to add to an error's message in place: frobnicate(arg, errp); error_prepend(errp, "Can't frobnicate %s: ", arg); Likewise, reporting an error like frobnicate(arg, &err); error_report("Can't frobnicate %s: %s", arg, error_get_pretty(err)); can lose err's hint. To avoid: error_reportf_err(err, "Can't frobnicate %s: ", arg); The next commits will put these functions to use. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <1450452927-8346-10-git-send-email-armbru@redhat.com>
2016-01-13error: Improve documentationMarkus Armbruster
While there, tighten error_append_hint()'s assertion. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <1450452927-8346-6-git-send-email-armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2016-01-13error: Document how to accumulate multiple errorsMarkus Armbruster
Suggested-by: Eric Blake <eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <1447776349-2344-1-git-send-email-armbru@redhat.com>
2015-12-17qapi: Shorter visits of optional fieldsEric Blake
For less code, reflect the determined boolean value of an optional visit back to the caller instead of making the caller read the boolean after the fact. The resulting generated code has the following diff: |- visit_optional(v, &has_fdset_id, "fdset-id"); |- if (has_fdset_id) { |+ if (visit_optional(v, &has_fdset_id, "fdset-id")) { | visit_type_int(v, &fdset_id, "fdset-id", &err); | if (err) { | goto out; | } | } Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1449033659-25497-10-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>