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>
No header includes qemu-common.h after this commit, as prescribed by
qemu-common.h's file comment.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20190523143508.25387-5-armbru@redhat.com>
[Rebased with conflicts resolved automatically, except for
include/hw/arm/xlnx-zynqmp.h hw/arm/nrf51_soc.c hw/arm/msf2-soc.c
block/qcow2-refcount.c block/qcow2-cluster.c block/qcow2-cache.c
target/arm/cpu.h target/lm32/cpu.h target/m68k/cpu.h target/mips/cpu.h
target/moxie/cpu.h target/nios2/cpu.h target/openrisc/cpu.h
target/riscv/cpu.h target/tilegx/cpu.h target/tricore/cpu.h
target/unicore32/cpu.h target/xtensa/cpu.h; bsd-user/main.c and
net/tap-bsd.c fixed up]
Before the from qerror_report() to error_setg(), hints looked like
this:
qerror_report(QERR_MACRO, ... arguments ...);
error_printf_unless_qmp(... hint ...);
error_printf_unless_qmp() made perfect sense: it printed exactly when
qerror_report() did.
After the conversion to error_setg():
error_setg(errp, QERR_MACRO, ... arguments ...);
error_printf_unless_qmp(... hint ...);
The "unless QMP part" still made some sense; in QMP context, the
caller generally uses the error as QMP response instead of printing
it.
However, everything else is wrong. If the caller handles the error,
the hint gets printed anyway (unless QMP). If the caller reports the
error, the hint gets printed *before* the report (unless QMP) or not
at all (if QMP).
Commit 50b7b000c9 fixed this by making hints a member of Error. It
kept printing hints with error_printf_unless_qmp():
void error_report_err(Error *err)
{
error_report("%s", error_get_pretty(err));
+ if (err->hint) {
+ error_printf_unless_qmp("%s\n", err->hint->str);
+ }
error_free(err);
}
This is wrong. We should (and now can) print the hint exactly when we
print the error.
The mistake has since been copied to warn_report_err() in commit
e43ead1d0b.
Fix both to use error_printf().
Reported-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Cc: Eric Blake <eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20190416153850.5186-1-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
[Commit message tweaked]
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>
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>
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>
When &error_abort is passed in, the error reporting code
will print the current error message and then abort() the
process. Unfortunately at the time it aborts, we've not
yet appended the errno detail. This makes debugging certain
problems significantly harder as the log is incomplete.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1457544504-8548-22-git-send-email-berrange@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
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>
Since commit 50b7b00, we have error_append_hint() to conveniently
accumulate Error member @hint. error_report_err() prints it with a
newline appended. Consequently, users of error_append_hint() need to
know whether theirs is the final line of the hint to decide whether it
needs a newline. Not a nice interface.
Change error_report_err() to print just the hint, and the (still few)
users of error_append_hint() to add the required newline.
Cc: Eric Blake <eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <1450370121-5768-7-git-send-email-armbru@redhat.com>
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>
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>
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>
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>
Duplicated when commit 680d16d added error_set_errno(), and again when
commit 20840d4 added error_set_win32().
Make the original copy in error_set() reusable by factoring out
error_setv(), then rewrite error_set_errno() and error_set_win32() on
top of it.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
