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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>
2016-03-22include/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>
2016-02-23include: 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>
2016-02-09error: 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: LluĂ­s Vilanova <vilanova@ac.upc.edu>
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: Change munging of CamelCase enum valuesEric Blake
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 Blake
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 Blake
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 Armbruster
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 Blake
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 Armbruster
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 Armbruster
Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2015-09-10error: error_set_errno() is unused, dropMarkus Armbruster
Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2015-09-10qga: Clean up unnecessarily dirty castsMarkus Armbruster
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 Armbruster
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 Armbruster
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 Armbruster
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 Armbruster
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 Crosthwaite
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 Sekiyama
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 Capitulino
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 Bonzini
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-12-19qapi: move include files to include/qobject/Paolo Bonzini
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>