On 07/23/2015 08:01 AM, Markus Armbruster wrote: > 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 > /work/armbru/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 <arm...@redhat.com> > --- > include/qapi/error.h | 43 +++++++++++++++++++++++++++-------- > qga/vss-win32.c | 2 +- > qga/vss-win32/requester.cpp | 5 +++-- > qga/vss-win32/requester.h | 6 +++-- > util/error.c | 55 > ++++++++++++++++++++++++++++++++------------- > 5 files changed, 81 insertions(+), 30 deletions(-) >
> +++ b/qga/vss-win32/requester.cpp > @@ -23,8 +23,9 @@ > /* Call QueryStatus every 10 ms while waiting for frozen event */ > #define VSS_TIMEOUT_EVENT_MSEC 10 > > -#define err_set(e, err, fmt, ...) \ > - ((e)->error_setg_win32((e)->errp, err, fmt, ## __VA_ARGS__)) > +#define err_set(e, err, fmt, ...) \ > + ((e)->error_setg_win32((e)->errp, __FILE__, __LINE__, __func__, \ > + err, fmt, ## __VA_ARGS__)) Indentation looks odd here, but not fatal. > -void error_setg_errno(Error **errp, int os_errno, const char *fmt, ...) > +void error_setg_errno_internal(Error **errp, > + const char *src, int line, const char *func, > + int os_errno, const char *fmt, ...) Indentation off again. Those are minor, and could be fixed by maintainer. Reviewed-by: Eric Blake <ebl...@redhat.com> -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
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