Eric Blake <ebl...@redhat.com> writes: > 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.
That would be me. I can fix them up for my pull request. > Reviewed-by: Eric Blake <ebl...@redhat.com> Thanks!
