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2024-03-12error: Add error_vprepend() in comment of ERRP_GUARD() rulesZhao Liu1-1/+1
The error_vprepend() should use ERRP_GUARD() just as the documentation of ERRP_GUARD() says: > It must be used when the function dereferences @errp or passes > @errp to error_prepend(), error_vprepend(), or error_append_hint(). Considering that error_vprepend() is also an API provided in error.h, it is necessary to add it to the description of the rules for using ERRP_GUARD(). Cc: Markus Armbruster <armbru@redhat.com> Cc: Michael Roth <michael.roth@amd.com> Signed-off-by: Zhao Liu <zhao1.liu@intel.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Message-ID: <20240311033822.3142585-2-zhao1.liu@linux.intel.com> Signed-off-by: Thomas Huth <thuth@redhat.com>
2023-03-13error: add global &error_warn destinationMarc-André Lureau1-0/+6
This can help debugging issues or develop, when error handling is introduced. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Message-Id: <20230221124802.4103554-6-marcandre.lureau@redhat.com>
2022-03-22Replace GCC_FMT_ATTR with G_GNUC_PRINTFMarc-André Lureau1-10/+10
One less qemu-specific macro. It also helps to make some headers/units only depend on glib, and thus moved in standalone projects eventually. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Richard W.M. Jones <rjones@redhat.com>
2021-03-05error: Fix "Converting to ERRP_GUARD()" doc on "valid at return"Markus Armbruster1-1/+1
Setting errp = NULL is wrong: the automatic error propagation still propagates the dangling pointer _auto_errp_prop.local_err. We need to set *errp = NULL to clear the dangling pointer. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20210125132635.1253219-1-armbru@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
2020-07-24qapi/error: Check format string argument in error_*prepend()Philippe Mathieu-Daudé1-2/+4
error_propagate_prepend() "behaves like error_prepend()", and error_prepend() uses "formatting @fmt, ... like printf()". error_prepend() checks its format string argument, but error_propagate_prepend() does not. Fix by addint the format attribute to error_propagate_prepend() and error_vprepend(). This would have caught the bug fixed in the previous commit. Missed in commit 4b5766488f "error: Fix use of error_prepend() with &error_fatal, &error_abort". Inspired-by: Stefan Weil <sw@weilnetz.de> Suggested-by: Eric Blake <eblake@redhat.com> Reviewed-by: Stefan Weil <sw@weilnetz.de> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> Message-Id: <20200723171205.14949-1-philmd@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> [Commit message tweaked] Signed-off-by: Markus Armbruster <armbru@redhat.com>
2020-07-10scripts: Coccinelle script to use ERRP_GUARD()Vladimir Sementsov-Ogievskiy1-0/+2
Script adds ERRP_GUARD() macro invocations where appropriate and does corresponding changes in code (look for details in include/qapi/error.h) Usage example: spatch --sp-file scripts/coccinelle/errp-guard.cocci \ --macro-file scripts/cocci-macro-file.h --in-place --no-show-diff \ --max-width 80 FILES... Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20200707165037.1026246-3-armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> [ERRP_AUTO_PROPAGATE() renamed to ERRP_GUARD(), and auto-propagated-errp.cocci to errp-guard.cocci]
2020-07-10error: New macro ERRP_GUARD()Vladimir Sementsov-Ogievskiy1-19/+139
Introduce a new ERRP_GUARD() macro, to be used at start of functions with an errp OUT parameter. It has three goals: 1. Fix issue with error_fatal and error_prepend/error_append_hint: the user can't see this additional information, because exit() happens in error_setg earlier than information is added. [Reported by Greg Kurz] 2. Fix issue with error_abort and error_propagate: when we wrap error_abort by local_err+error_propagate, the resulting coredump will refer to error_propagate and not to the place where error happened. (the macro itself doesn't fix the issue, but it allows us to [3.] drop the local_err+error_propagate pattern, which will definitely fix the issue) [Reported by Kevin Wolf] 3. Drop local_err+error_propagate pattern, which is used to workaround void functions with errp parameter, when caller wants to know resulting status. (Note: actually these functions could be merely updated to return int error code). To achieve these goals, later patches will add invocations of this macro at the start of functions with either use error_prepend/error_append_hint (solving 1) or which use local_err+error_propagate to check errors, switching those functions to use *errp instead (solving 2 and 3). Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Paul Durrant <paul@xen.org> Reviewed-by: Greg Kurz <groug@kaod.org> Reviewed-by: Eric Blake <eblake@redhat.com> [Merge comments properly with recent commit "error: Document Error API usage rules", and edit for clarity. Put ERRP_AUTO_PROPAGATE() before its helpers, and touch up style. Tweak commit message.] Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20200707165037.1026246-2-armbru@redhat.com> [Rename ERRP_AUTO_PROPAGATE() to ERRP_GUARD(), tweak commit message again]
2020-07-10error: Document Error API usage rulesMarkus Armbruster1-6/+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]
2020-07-10error: Improve error.h's big commentMarkus Armbruster1-15/+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>
2020-07-10error: Fix examples in error.h's big commentMarkus Armbruster1-2/+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>
2019-12-18error: make Error **errp const where it is appropriateVladimir Sementsov-Ogievskiy1-3/+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>
2019-08-16qapi: Split error.json off common.jsonMarkus Armbruster1-1/+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>
2018-10-19error: Fix use of error_prepend() with &error_fatal, &error_abortMarkus Armbruster1-0/+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>
2018-03-02Include less of the generated modular QAPI headersMarkus Armbruster1-1/+1
In my "build everything" tree, a change to the types in qapi-schema.json triggers a recompile of about 4800 out of 5100 objects. The previous commit split up qmp-commands.h, qmp-event.h, qmp-visit.h, qapi-types.h. Each of these headers still includes all its shards. Reduce compile time by including just the shards we actually need. To illustrate the benefits: adding a type to qapi/migration.json now recompiles some 2300 instead of 4800 objects. The next commit will improve it further. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20180211093607.27351-24-armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> [eblake: rebase to master] Signed-off-by: Eric Blake <eblake@redhat.com>
2018-02-06error: Improve documentation of error_append_hint()Markus Armbruster1-0/+8
Suggested-by: Halil Pasic <pasic@linux.vnet.ibm.com> Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <1502359588-29451-1-git-send-email-armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Halil Pasic <pasic@linux.vnet.ibm.com>
2017-07-14Merge remote-tracking branch 'remotes/armbru/tags/pull-error-2017-07-13' ↵Peter Maydell1-0/+11
into staging Error reporting patches for 2017-07-13 # gpg: Signature made Thu 13 Jul 2017 12:55:45 BST # gpg: using RSA key 0x3870B400EB918653 # 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-error-2017-07-13: Convert error_report*_err() to warn_report*_err() error: Implement the warn and free Error functions char-socket: Report TCP socket waiting as information Convert error_report() to warn_report() error: Functions to report warnings and informational messages util/qemu-error: Rename error_print_loc() to be more generic websock: Don't try to set *errp directly block: Don't try to set *errp directly xilinx: Fix latent error handling bug Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2017-07-13error: Implement the warn and free Error functionsAlistair Francis1-0/+11
Implement warn_report_err() and warn_reportf_err() functions which are the same as the error_report_err() and error_reportf_err() functions except report a warning instead of an error. Signed-off-by: Alistair Francis <alistair.francis@xilinx.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Message-Id: <276ff93eadc0b01b8243cc61ffc331f77922c0d0.1499866456.git.alistair.francis@xilinx.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2017-07-11block: remove all encryption handling APIsDaniel P. Berrange1-1/+0
Now that all encryption keys must be provided upfront via the QCryptoSecret API and associated block driver properties there is no need for any explicit encryption handling APIs in the block layer. Encryption can be handled transparently within the block driver. We only retain an API for querying whether an image is encrypted or not, since that is a potentially useful piece of metadata to report to the user. Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Daniel P. Berrange <berrange@redhat.com> Message-id: 20170623162419.26068-18-berrange@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-01-19error: error_setg_errno(): errno gets preservedSascha Silbe1-0/+3
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>
2016-05-26migration: add reporting of errors for outgoing migrationDaniel P. Berrange1-1/+1
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>
2016-03-22include/qemu/osdep.h: Don't include qapi/error.hMarkus Armbruster1-5/+0
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>
2016-02-23include: Clean up includesPeter Maydell1-3/+0
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>
2016-02-09error: Improve documentation some moreMarkus Armbruster1-4/+11
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>
2016-01-13error: New error_prepend(), error_reportf_err()Markus Armbruster1-2/+29
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 Armbruster1-2/+18
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 Armbruster1-0/+17
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: Change munging of CamelCase enum valuesEric Blake1-6/+6
When munging enum values, the fact that we were passing the entire prefix + value through camel_to_upper() meant that enum values spelled with CamelCase could be turned into CAMEL_CASE. However, this provides a potential collision (both OneTwo and One-Two would munge into ONE_TWO) for enum types, when the same two names are valid side-by-side as QAPI member names. By changing the generation of enum constants to always be prefix + '_' + c_name(value, False).upper(), and ensuring that there are no case collisions (in the next patches), we no longer have to worry about names that would be distinct as QAPI members but collide as variant tag names, without having to think about what munging the heuristics in camel_to_upper() will actually perform on an enum value. Making the change will affect enums that did not follow coding conventions, using 'CamelCase' rather than desired 'lower-case'. Thankfully, there are only two culprits: InputButton and ErrorClass. We already tweaked ErrorClass to make it an alias of QapiErrorClass, where only the alias needs changing rather than the whole tree. So the bulk of this change is modifying INPUT_BUTTON_WHEEL_UP to the new INPUT_BUTTON_WHEELUP (and likewise for WHEELDOWN). That part of this commit may later need reverting if we rename the enum constants from 'WheelUp' to 'wheel-up' as part of moving x-input-send-event to a stable interface; but at least we have documentation bread crumbs in place to remind us (commit 513e7cd), and it matches the fact that SDL constants are also spelled SDL_BUTTON_WHEELUP. Suggested by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1447836791-369-27-git-send-email-eblake@redhat.com> [Commit message tweaked] Signed-off-by: Markus Armbruster <armbru@redhat.com>
2015-12-17qapi: Add alias for ErrorClassEric Blake1-0/+14
The qapi enum ErrorClass is unusual that it uses 'CamelCase' names, contrary to our documented convention of preferring 'lower-case'. However, this enum is entrenched in the API; we cannot change what strings QMP outputs. Meanwhile, we want to simplify how c_enum_const() is used to generate enum constants, by moving away from the heuristics of camel_to_upper() to a more straightforward c_name(N).upper() - but doing so will rename all of the ErrorClass constants and cause churn to all client files, where the new names are aesthetically less pleasing (ERROR_CLASS_DEVICENOTFOUND looks like we can't make up our minds on whether to break between words). So as always in computer science, solve the problem by some more indirection: rename the qapi type to QapiErrorClass, and add a new enum ErrorClass in error.h whose members are aliases of the qapi type, but with the spelling expected elsewhere in the tree. Then, when c_enum_const() changes the munging, we only have to adjust the one alias spot. Suggested by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1447836791-369-26-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2015-11-10qapi: Simplify error cleanup in test-qmp-*Eric Blake1-0/+9
We have several tests that perform multiple sub-actions that are expected to fail. Asserting that an error occurred, then clearing it up to prepare for the next action, turned into enough boilerplate that it was sometimes forgotten (for example, a number of tests added to test-qmp-input-visitor.c in d88f5fd leaked err). Worse, if an error is not reset to NULL, we risk invalidating later use of that error (passing a non-NULL err into a function is generally a bad idea). Encapsulate the boilerplate into a single helper function error_free_or_abort(), and consistently use it. The new function is added into error.c for use everywhere, although it is anticipated that testsuites will be the main client. Signed-off-by: Eric Blake <eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2015-09-18error: New error_fatalMarkus Armbruster1-0/+11
Similar to error_abort, but doesn't report where the error was created, and terminates the process with exit(1) rather than abort(). Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <1441983105-26376-2-git-send-email-armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Peter Crosthwaite <crosthwaite.peter@gmail.com>
2015-09-18hmp: Allow for error message hints on HMPEric Blake1-0/+7
Commits 7216ae3d and d2828429 disabled some error message hints, all because a change to use modern error reporting meant that the hint would be output prior to the actual error. Fix this by making hints a first-class member of Error. For example, we are now back to the pleasant: $ qemu-system-x86_64 --nodefaults -S --vnc :0 --chardev null,id=, qemu-system-x86_64: --chardev null,id=,: Parameter 'id' expects an identifier Identifiers consist of letters, digits, '-', '.', '_', starting with a letter. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <1441901956-21991-1-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2015-09-10error: On abort, report where the error was createdMarkus Armbruster1-9/+34
This is particularly useful when we abort in error_propagate(), because there the stack backtrace doesn't lead to where the error was created. Looks like this: Unexpected error in parse_block_error_action() at .../qemu/blockdev.c:322: qemu-system-x86_64: -drive if=none,werror=foo: 'foo' invalid write error action Aborted (core dumped) Note: to get this example output, I monkey-patched drive_new() to pass &error_abort to blockdev_init(). To keep the error handling boiler plate from growing even more, all error_setFOO() become macros expanding into error_setFOO_internal() with additional __FILE__, __LINE__, __func__ arguments. Not exactly pretty, but it works. The macro trickery breaks down when you take the address of an error_setFOO(). Fortunately, we do that in just one place: qemu-ga's Windows VSS provider and requester DLL wants to call error_setg_win32() through a function pointer "to avoid linking glib to the DLL". Use error_setg_win32_internal() there. The use of the function pointer is already wrapped in a macro, so the churn isn't bad. Code size increases by some 35KiB for me (0.7%). Tolerable. Could be less if we passed relative rather than absolute source file names to the compiler, or forwent reporting __func__. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Acked-by: Laszlo Ersek <lersek@redhat.com>
2015-09-10error: Revamp interface documentationMarkus Armbruster1-47/+124
Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2015-09-10error: error_set_errno() is unused, dropMarkus Armbruster1-5/+2
Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2015-09-10qga: Clean up unnecessarily dirty castsMarkus Armbruster1-7/+2
qga_vss_fsfreeze() casts error_set_win32() from void (*)(Error **, int, ErrorClass, const char *, ...) to void (*)(void **, int, int, const char *, ...) The result is later called. Since the two types are not compatible, the call is undefined behavior. It works in practice anyway. However, there's no real need for trickery here. Clean it up as follows: * Declare struct Error, and fix the first parameter. * Switch to error_setg_win32(). This gets rid of the troublesome ErrorClass parameter. Requires converting error_setg_win32() from macro to function, but that's trivially easy, because this is the only user of error_set_win32(). Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2015-09-10error: Make error_setg() a functionMarkus Armbruster1-2/+2
Saves a tiny amount of code at every call site. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2015-02-18error: New convenience function error_report_err()Markus Armbruster1-0/+5
I've typed error_report("%s", error_get_pretty(ERR)) too many times already, and I've fixed too many instances of qerror_report_err(ERR) to error_report("%s", error_get_pretty(ERR)) as well. Capture the pattern in a convenience function. Since it's almost invariably followed by error_free(), stuff that into the convenience function as well. The next patch will put it to use. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2014-05-21error: error_is_set() is finally unused; removeMarkus Armbruster1-6/+0
Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2014-05-09error: Consistently name Error ** objects errp, and not errMarkus Armbruster1-11/+16
Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-01-06error: Add error_abortPeter Crosthwaite1-0/+6
Add a special Error * that can be passed to error handling APIs to signal that any errors are fatal and should abort QEMU. There are two advantages to this: - allows for brevity when wishing to assert success of Error ** accepting APIs. No need for this pattern: Error * local_err = NULL; api_call(foo, bar, &local_err); assert_no_error(local_err); This also removes the need for _nofail variants of APIs with asserting call sites now reduced to 1LOC. - SIGABRT happens from within the offending API. When a fatal error occurs in an API call (when the caller is asserting sucess) failure often means the API itself is broken. With the abort happening in the API call now, the stack frames into the call are available at debug time. In the assert_no_error scheme the abort happens after the fact. The exact semantic is that when an error is raised, if the argument Error ** matches &error_abort, then the abort occurs immediately. The error messaged is reported. For error_propagate, if the destination error is &error_abort, then the abort happens at propagation time. Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2013-09-09error: Add error_set_win32 and error_setg_win32Tomoki Sekiyama1-0/+13
These functions help maintaining homogeneous formatting of error messages with Windows error code and description (generated by g_win32_error_message()). Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama@hds.com> Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com> Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2013-06-17error: add error_setg_file_open() helperLuiz Capitulino1-0/+5
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com> Acked-by: Kevin Wolf <kwolf@redhat.com>
2012-12-19misc: move include files to include/qemu/Paolo Bonzini1-1/+1
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-12-19qapi: move include files to include/qobject/Paolo Bonzini1-0/+80
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>