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>
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>
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>
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>
